The Midcontinent rift system is a 1.1-b.y.-old structure extending from Kansas, through the Lake Superior region, and into southern Michigan. The rift is filled with thick sequences of basaltic volcanic rocks and clastic sediments. For most of its extent it is buried beneath Paleozoic rocks but can be traced by its strong gravity and magnetic anomalies. The rocks of the rift system are exposed only in the Lake Superior region and comprise the Keweenawan Supergroup. Much of the geology of the Keweenawan is beneath Lake Superior and has only been inferred from potential field studies and seismic refraction studies and extrapolation from on-shore geology. Seismic reflection surveys by the Great Lakes International Multidisciplinary Program on Crustal Evolution in 1986 imaged much of the deep structure of the rift beneath the lake in detail. The reflection profiles across the rift reveal a deep, asymmetrical central graben whose existence and magnitude was not previously documented. They show that, in addition to crustal sagging documented by previous investigations, normal faulting played a major role in subsidence of the axial region of the rift. A sequence of volcanic and sedimentary rocks, in places greater than 30 km thick, fills the graben. Thinner volcanic and sedimentary units lie on broad flanks of the rift outside of the graben. Near the axis, the prerift crust is thinned to about one fourth of its original thickness, apparently by a combination of low-angle extensional faulting and ductile stretching or distributed shear. The sense of asymmetry of the central graben changes along the trend of the rift, documenting the segmented nature of the structure and suggesting the existence of accommodation zones between the segments. The location of the accommodation zones is inferred from abrupt disruptions in the Bouguer gravity signature of the rift. Uplift of the central graben occurred when the original graben-bounding normal faults were reactivated as high-angle reverse faults with throws of 5 km or more in places. The Midcontinent rift has some striking similarities to some younger passive continental margins. We propose that it preserves a record of nearly complete continental separation which, had it not been arrested, would have created a Middle Proterozoic ocean basin.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/TC008i002p00305","issn":"02787407","usgsCitation":"Cannon, W., Green, A., Hutchinson, D.R., Lee, M.W., Milkereit, B., Behrendt, J.C., Halls, H.C., Green, J., Dickas, A.B., Morey, G.B., Sutcliffe, R., and Spencer, C., 1989, The North American Midcontinent rift beneath Lake Superior from GLIMPCE seismic reflection profiling: Tectonics, v. 8, no. 2, p. 305-332, https://doi.org/10.1029/TC008i002p00305.","productDescription":"28 p.","startPage":"305","endPage":"332","costCenters":[],"links":[{"id":224004,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Canada, United States","otherGeospatial":"Lake Superior","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -93.6107180333476,\n 49.98394718840376\n ],\n [\n -93.6107180333476,\n 46.23771536321638\n ],\n [\n -84.18295176471604,\n 46.23771536321638\n ],\n [\n -84.18295176471604,\n 49.98394718840376\n ],\n [\n -93.6107180333476,\n 49.98394718840376\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"8","issue":"2","noUsgsAuthors":false,"publicationDate":"2010-07-26","publicationStatus":"PW","scienceBaseUri":"505ba858e4b08c986b321b76","contributors":{"authors":[{"text":"Cannon, W.F. 0000-0002-2699-8118","orcid":"https://orcid.org/0000-0002-2699-8118","contributorId":70382,"corporation":false,"usgs":true,"family":"Cannon","given":"W.F.","affiliations":[],"preferred":false,"id":371668,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Green, Alan G.","contributorId":80680,"corporation":false,"usgs":true,"family":"Green","given":"Alan G.","affiliations":[],"preferred":false,"id":948174,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hutchinson, D. R.","contributorId":31770,"corporation":false,"usgs":true,"family":"Hutchinson","given":"D.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":948175,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Lee, Myung W. mlee@usgs.gov","contributorId":779,"corporation":false,"usgs":true,"family":"Lee","given":"Myung","email":"mlee@usgs.gov","middleInitial":"W.","affiliations":[{"id":164,"text":"Central Energy Resources Science Center","active":true,"usgs":true}],"preferred":true,"id":948176,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Milkereit, Bernd","contributorId":62752,"corporation":false,"usgs":false,"family":"Milkereit","given":"Bernd","affiliations":[],"preferred":false,"id":948177,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Behrendt, John C. jbehrendt@usgs.gov","contributorId":25945,"corporation":false,"usgs":true,"family":"Behrendt","given":"John","email":"jbehrendt@usgs.gov","middleInitial":"C.","affiliations":[{"id":213,"text":"Crustal Imaging and Characterization Team","active":false,"usgs":true},{"id":218,"text":"Denver Federal Center","active":false,"usgs":true}],"preferred":false,"id":948178,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Halls, Henry C.","contributorId":361047,"corporation":false,"usgs":false,"family":"Halls","given":"Henry","middleInitial":"C.","affiliations":[],"preferred":false,"id":948179,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Green, J.C.","contributorId":90052,"corporation":false,"usgs":true,"family":"Green","given":"J.C.","email":"","affiliations":[],"preferred":false,"id":948180,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Dickas, Albert B.","contributorId":361048,"corporation":false,"usgs":false,"family":"Dickas","given":"Albert","middleInitial":"B.","affiliations":[],"preferred":false,"id":948181,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Morey, G. B.","contributorId":14406,"corporation":false,"usgs":true,"family":"Morey","given":"G.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":948182,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Sutcliffe, Richard","contributorId":361051,"corporation":false,"usgs":false,"family":"Sutcliffe","given":"Richard","affiliations":[],"preferred":false,"id":948183,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Spencer, C.","contributorId":361055,"corporation":false,"usgs":false,"family":"Spencer","given":"C.","affiliations":[],"preferred":false,"id":948184,"contributorType":{"id":1,"text":"Authors"},"rank":12}]}} ,{"id":70015407,"text":"70015407 - 1989 - Taconic plate kinematics as revealed by foredeep stratigraphy, Appalachian orogen","interactions":[],"lastModifiedDate":"2025-09-09T16:53:48.049201","indexId":"70015407","displayToPublicDate":"2010-07-26T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3524,"text":"Tectonics","active":true,"publicationSubtype":{"id":10}},"title":"Taconic plate kinematics as revealed by foredeep stratigraphy, Appalachian orogen","docAbstract":"Destruction of the Ordovician passive margin of eastern North America is recorded by an upward deepening succession of carbonates, shales, and flysch. A compilation of the age of shelf drowning (carbonate-to-shale transition) reveals the degree to which orogeny was diachronous both across and along strike. Shelf drowning occurred first at the northern end of the orogen in Newfoundland, then at the southern end of the orogen in Georgia, and finally in Quebec. Diachronism is attributed to oblique collision between an irregular passive margin, that had a deep embayment in Quebec, and at least one east dipping subduction complex. The rate of plate convergence during collision is estimated at 1 to 2 cm/yr, and the minimum width of the ocean that closed is estimated at 500 to 900 km. Far-traveled deepwater sequences in the thrust belt contain anomalously old Taconic flysch, related to early arrival of the continental slope/rise at a west advancing trench then located far to the east. The drowning isochron map provides a new basis for estimating tectonic transport distances of four of these allochthons (about 165 to 450 km), results not readily obtained by conventional structural analysis.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/TC008i005p01037","issn":"02787407","usgsCitation":"Bradley, D.C., 1989, Taconic plate kinematics as revealed by foredeep stratigraphy, Appalachian orogen: Tectonics, v. 8, no. 5, p. 1037-1049, https://doi.org/10.1029/TC008i005p01037.","productDescription":"13 p.","startPage":"1037","endPage":"1049","costCenters":[],"links":[{"id":224307,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Canada, United States","otherGeospatial":"Appalachian Mountains","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -59.94794184613204,\n 53.783005810210994\n ],\n [\n -66.52193972184966,\n 49.42391661877889\n ],\n [\n -84.05589482730278,\n 32.29826164743447\n ],\n [\n -82.25406401000738,\n 31.27460409801749\n ],\n [\n -72.41174206402178,\n 42.00001551829209\n ],\n [\n -60.01457676108012,\n 51.99456174559443\n ],\n [\n -59.94794184613204,\n 53.783005810210994\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"8","issue":"5","noUsgsAuthors":false,"publicationDate":"2010-07-26","publicationStatus":"PW","scienceBaseUri":"505ba3ace4b08c986b31fdee","contributors":{"authors":[{"text":"Bradley, D. C.","contributorId":17634,"corporation":false,"usgs":true,"family":"Bradley","given":"D.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":370869,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":5223242,"text":"5223242 - 1989 - Longevity records of North American birds. Supplement 1","interactions":[],"lastModifiedDate":"2012-02-02T00:15:35","indexId":"5223242","displayToPublicDate":"2010-06-16T12:19:11","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2284,"text":"Journal of Field Ornithology","active":true,"publicationSubtype":{"id":10}},"title":"Longevity records of North American birds. Supplement 1","docAbstract":"This is the first supplement to the previous published four-part series on avian longevities (Clapp et al. 1982, 1983; Klimkiewicz et al. 1983; Klimkiewicz and Futcher 1987). R ecords processed in the Bird Banding Laboratory through August 1988 are included, as well as several corrections to the original series. One hundred-seven of the 147 entries in this supplement are new longevity records for species or forms listed previously. Another 37 entries represent taxa not listed before, and the remaining three records correct previous listings that were in error.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Field Ornithology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","usgsCitation":"Klimkiewicz, M.K., and Futcher, A., 1989, Longevity records of North American birds. Supplement 1: Journal of Field Ornithology, v. 60, no. 4, p. 469-494.","productDescription":"469-494","startPage":"469","endPage":"494","numberOfPages":"26","costCenters":[{"id":531,"text":"Patuxent Wildlife Research Center","active":true,"usgs":true}],"links":[{"id":18039,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://elibrary.unm.edu/sora/JFO/v060n04/p0469-p0494.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":201958,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"60","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a6de4b07f02db63f08f","contributors":{"authors":[{"text":"Klimkiewicz, M. K.","contributorId":53490,"corporation":false,"usgs":true,"family":"Klimkiewicz","given":"M.","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":338194,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Futcher, A.G.","contributorId":102170,"corporation":false,"usgs":true,"family":"Futcher","given":"A.G.","email":"","affiliations":[],"preferred":false,"id":338195,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":5222294,"text":"5222294 - 1989 - Selenium accumulation by raccoons exposed to irrigation drainwater at Kesterson National Wildlife Refuge, California, 1986","interactions":[],"lastModifiedDate":"2023-12-12T15:27:13.135743","indexId":"5222294","displayToPublicDate":"2010-06-16T12:19:07","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":887,"text":"Archives of Environmental Contamination and Toxicology","active":true,"publicationSubtype":{"id":10}},"title":"Selenium accumulation by raccoons exposed to irrigation drainwater at Kesterson National Wildlife Refuge, California, 1986","docAbstract":"In February–March 1986, eight raccoons (Procyon lotor) were collected at Kesterson Reservoir (Merced Co., California), which had received selenium-contaminated irrigation drainwater, and four raccoons were collected at the nearby Volta Wildlife Area, which had not. Selenium concentrations in Kesterson raccoons averaged 19.9 ppm (μg/g dry wt) in liver, 28.3 ppm (dry wt) in hair, 21.6 ppm (dry wt) in feces, and 2.61 ppm (wet wt) in blood and exceeded Volta concentrations by 12, 30, 21, and 10 times, respectively. Selenium concentrations in livers of Kesterson raccoons were less than those in five of nine other mammal species sampled in 1984. Selenium concentrations in hair provided the strongest statistical separation between study areas. Hemoglobin levels in two Kesterson raccoons equalled levels reported in rats with selenium-induced anemia, but the raccoons showed no illness. Amyloidosis in one Kesterson raccoon may have been selenium-induced. Our data indicate that raccoon births peaked about 2 months later than was previously reported. Based on our sample of 12 raccoons, we found no evidence that contamination by irrigation drainwater had negative effects on raccoons inhabiting Kesterson.
","language":"English","publisher":"Springer","doi":"10.1007/BF01160292","usgsCitation":"Clark, D.R., Ogasawara, P.A., Smith, G.J., and Ohlendorf, H.M., 1989, Selenium accumulation by raccoons exposed to irrigation drainwater at Kesterson National Wildlife Refuge, California, 1986: Archives of Environmental Contamination and Toxicology, v. 18, no. 6, p. 787-794, https://doi.org/10.1007/BF01160292.","productDescription":"8 p.","startPage":"787","endPage":"794","numberOfPages":"8","costCenters":[{"id":531,"text":"Patuxent Wildlife Research Center","active":true,"usgs":true}],"links":[{"id":193417,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","otherGeospatial":"Kesterson National Wildlife Refuge","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -120.95302876323598,\n 37.305788447104575\n ],\n [\n -120.95302876323598,\n 37.232121386550006\n ],\n [\n -120.85131934497143,\n 37.232121386550006\n ],\n [\n -120.85131934497143,\n 37.305788447104575\n ],\n [\n -120.95302876323598,\n 37.305788447104575\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"18","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a00e4b07f02db5f7ce1","contributors":{"authors":[{"text":"Clark, Donald R. Jr.","contributorId":118204,"corporation":false,"usgs":false,"family":"Clark","given":"Donald","suffix":"Jr.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":336007,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ogasawara, P. A.","contributorId":95160,"corporation":false,"usgs":true,"family":"Ogasawara","given":"P.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":336009,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Smith, Gregory J. gsmith@usgs.gov","contributorId":263871,"corporation":false,"usgs":true,"family":"Smith","given":"Gregory","email":"gsmith@usgs.gov","middleInitial":"J.","affiliations":[],"preferred":true,"id":336008,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ohlendorf, Harry M.","contributorId":60291,"corporation":false,"usgs":true,"family":"Ohlendorf","given":"Harry","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":336006,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":5222274,"text":"5222274 - 1989 - Annual survival rates of breeding adult roseate terns","interactions":[],"lastModifiedDate":"2017-05-13T15:24:41","indexId":"5222274","displayToPublicDate":"2010-06-16T12:19:07","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3544,"text":"The Auk","onlineIssn":"1938-4254","printIssn":"0004-8038","active":true,"publicationSubtype":{"id":10}},"title":"Annual survival rates of breeding adult roseate terns","docAbstract":"During 1983-1985, we studied the reproductive success of several species of aquatic birds (coots, ducks, shorebirds, and grebes) nesting at two sites in Merced County, California: a selenium-contaminated site (Kesterson Reservoir) and a nearby reference site (Volta Wildlife Area). We used a computer program (MICROMORT) developed for the analysis of radiotelemetry data (Heisey and Fuller 1985) to estimate nest success and cause-specific failure rates, and then compared these parameters and hatchability between sites and among years. Nest success and causes of failure varied by species, site, and year. The most important causes of nest failure were usually predation, desertion, and water-level changes. However, embryotoxicosis (mortality, deformity, and lack of embryonic development) was the most important cause of nest failure in Eared Grebes (Podiceps nigricollis) at Kesterson Reservoir. Embryotoxicosis also reduced the hatchability of eggs of all other species at Kesterson in one or more years; embryonic mortality occurred rarely at Volta, and abnormalities were not observed.
","language":"English","publisher":"Cooper Ornithological Society","doi":"10.2307/1368061","usgsCitation":"Ohlendorf, H.M., Hothem, R.L., and Welsh, D., 1989, Nest success, cause-specific nest failure, and hatchability of aquatic birds at selenium-contaminated Kesterson Reservoir and a reference site: The Condor, v. 91, no. 4, p. 787-796, https://doi.org/10.2307/1368061.","productDescription":"10 p.","startPage":"787","endPage":"796","costCenters":[{"id":531,"text":"Patuxent Wildlife Research Center","active":true,"usgs":true},{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":196610,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","county":"Merced County","otherGeospatial":"Kesterson Reservoir, Volta Wildlife Area","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -121.20597839355467,\n 36.86698689106877\n ],\n [\n -120.53375244140625,\n 36.86698689106877\n ],\n [\n -120.53375244140625,\n 37.35269280367274\n ],\n [\n -121.20597839355467,\n 37.35269280367274\n ],\n [\n -121.20597839355467,\n 36.86698689106877\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"91","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b24e4b07f02db6ae7c1","contributors":{"authors":[{"text":"Ohlendorf, Harry M.","contributorId":60291,"corporation":false,"usgs":true,"family":"Ohlendorf","given":"Harry","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":336034,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hothem, Roger L. roger_hothem@usgs.gov","contributorId":1721,"corporation":false,"usgs":true,"family":"Hothem","given":"Roger","email":"roger_hothem@usgs.gov","middleInitial":"L.","affiliations":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"preferred":true,"id":336036,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Welsh, Daniel","contributorId":181869,"corporation":false,"usgs":false,"family":"Welsh","given":"Daniel","email":"","affiliations":[{"id":6711,"text":"University of Idaho, Moscow ID","active":true,"usgs":false}],"preferred":false,"id":336035,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70015356,"text":"70015356 - 1989 - Geology of the Zambales ophiolite, Luzon, Philippines","interactions":[],"lastModifiedDate":"2025-08-20T16:48:39.59571","indexId":"70015356","displayToPublicDate":"2003-04-14T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3525,"text":"Tectonophysics","active":true,"publicationSubtype":{"id":10}},"title":"Geology of the Zambales ophiolite, Luzon, Philippines","docAbstract":"The Zambales ophiolite of western Luzon, Philippines, exposes a typical succession of basalt flows, diabasic dikes, gabbro and tectonized harzburgite. The age established by limiting strata is late Eocene. Lack of evidence of thrust faulting and the general domal disposition of the lithologie units indicate that the ophiolitic rocks are exposed by uplift. Highly complex internal layered structures within the complex are related to processes developed during formation of the ophiolite and the Zambales ophiolite may be one of the least disturbed (by emplacement) ophiolitic masses known.
The exposed mass trends north and the upper surface plunges at low angles (a few degrees) to the north and south. The chemistry and composition of the rocks in the northwest part of the Zambales area (Acoje block) is distinct from that in the southeastern segment (Coto block). The Acoje block, according to Evans (1983) and Hawkins and Evans (1983), resembles (on a chemical basis) arc-tholeiite series rocks from intra-island arcs and the rocks in the Coto block are typical back-arc basin rock series. The present writer believes that the ophiolite composes a single genetic unit and that the changes in composition are the result of changes that took place during the initial formation. The gabbro probably formed below a spreading center in an elongate, in cross section, V-shaped, magma chamber. The gabbro is estimated by the writer to be less than 2 km thick and may be less than 1 km in places. Numerous erosional windows through the gabbro in the northern and eastern side of the Zambales area show that the gabbro remaining in those areas is likely to be only a few hundred meters thick. Harzburgite is exposed to a depth of about 800 m in the Bagsit River area and this may be the deepest part of the ophiolite accessible for study on which there is any control on depth. A transitional zone, about 200 m thick lying between the gabbro and harzburgite, is composed of serpentinized dunite. Commonly the dunite contains disseminated sulfide minerals and at the Acoje Mines, platinum-group elements.
A compositional layering within the gabbro is in places cumulate in the lower part of the unit but may have formed by nucleation higher up on the relatively steep sides of the magma chamber. A widespread gneissic banding in the gabbro forms large mappable structures which are many times more complex than is the disposition of the major rock units. These structures are believed to be the result of extensive slumping in the magma chamber. The structure produced by the cumulate layering merges with the gneissic banding, commonly without discernible change in attitude. This tectonic layered structure crosses the gabbro-peridotite boundary at any angle without seeming to disturb the original rock distribution. At greater depths below the boundary (ca. 800 m), the harzburgite contains low dipping banding, which probably reflects the result of differential movement within the mantle.
Chromite occurs almost exclusively in a zone that generally lies no more than 200–300 m below the gabbro-peridotite boundary. Refractory-grade chromite is found in this zone below the olivine gabbro in the Goto block and as low-grade metallurgical grade chromite below norite in the Acoje block. At Acoje Mines the chromite is present in layers in dunite, which the writer interprets as being distributed in a zone along the gently dipping (ca. 25°) gabbro-peridotite boundary. The steeply dipping (ca. 60–80 ° ) individual layers lie en echelon along the boundary at an angle (ca. 50 ° ) to the contact. At Coto the chromite forms large discontinuous masses in the lowest dunite and in the uppermost harzburgite. Except for the chromite present as layers at Acoje, the regional tectonic layering crosses the chromite deposits without structural deviation. The chromite deposits and associated peridotite may be cumulate in origin, but have been modified to such an extent that cumulate textures are generally obliterated. The angle of repose of cumulate layers in the Acoje area and in the Coto block dip towards each other raising the possibility that the Zambales area may contain the relics of a spreading center.
Initial emplacement of the Zambales ophiolite took place by uplift and the ultramafic portion was exposed to erosion in the earliest Miocene or late Oligocene. Submergence of some of the ophiolite followed the previous uplift and on the west side of the Zambales Range submergence of several kilometers is indicated. Final emergence appears to have taken place in Pliocene or Pleistocene time by block uplift and areas of greatest uplift closely conform to the present topographic surface.
","language":"English","publisher":"Elsevier","doi":"10.1016/0040-1951(89)90366-1","issn":"00401951","usgsCitation":"Rossman, D.L., Castanada, G., and Bacuta, G., 1989, Geology of the Zambales ophiolite, Luzon, Philippines: Tectonophysics, v. 168, no. 1-3, p. 1-22, https://doi.org/10.1016/0040-1951(89)90366-1.","productDescription":"19 p.","startPage":"1","endPage":"22","costCenters":[],"links":[{"id":224306,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Philippines","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n 120.01436353828899,\n 16.379018641910505\n ],\n [\n 120.01436353828899,\n 14.71257942771895\n ],\n [\n 120.64963935647586,\n 14.71257942771895\n ],\n [\n 120.64963935647586,\n 16.379018641910505\n ],\n [\n 120.01436353828899,\n 16.379018641910505\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"168","issue":"1-3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a26d5e4b0c8380cd593bc","contributors":{"authors":[{"text":"Rossman, Darwin L.","contributorId":94663,"corporation":false,"usgs":true,"family":"Rossman","given":"Darwin","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":370729,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Castanada, G.C.","contributorId":49115,"corporation":false,"usgs":true,"family":"Castanada","given":"G.C.","email":"","affiliations":[],"preferred":false,"id":370728,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bacuta, G.C.","contributorId":26817,"corporation":false,"usgs":true,"family":"Bacuta","given":"G.C.","affiliations":[],"preferred":false,"id":370727,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014985,"text":"70014985 - 1989 - Stetson Pit, Dare County, North Carolina: An integrated chronologic, faunal, and floral record of subsurface coastal quaternary sediments","interactions":[],"lastModifiedDate":"2025-06-11T15:39:41.597172","indexId":"70014985","displayToPublicDate":"2003-04-02T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2996,"text":"Palaeogeography, Palaeoclimatology, Palaeoecology","printIssn":"0031-0182","active":true,"publicationSubtype":{"id":10}},"title":"Stetson Pit, Dare County, North Carolina: An integrated chronologic, faunal, and floral record of subsurface coastal quaternary sediments","docAbstract":"Continuous split spoon samples from a drill hole penetrating 34 m of coastal plain sediments at Stetson Pit in Dare County, North Carolina were taken for lithologic, aminostratigraphic, faunal (ostracodes) and floral (pollen) analyses. Three distinct aminozones are recognized in the subsurface section based upon D-alloisoleucine/L-isoleucine (A/I) values in each of the molluscan species Mulinia lateralis and Mercenaria sp. Ostracode zonations in the subsurface section are based on percentages of 80 thermophilic and cryophilic species (those living today south and north of Cape Hatteras) and the percentages of brackish water species. Five assemblage zones are delineated. Six pollen assemblage zones are also delineated within the subsurface section based upon study of 48 sediment samples. The subsurface record at Stetson Pit is interpreted to represent portions of four interglacials based upon the combined faunal, floral and aminostratigraphic data. The two younger aminozones, with amino acid age estimates of 100,000±20,000 yr (−7.2 to −11.2 m MSL) and 300,000–500,000 yr (−13 to −14.2 m MSL), represent portions of middle/late Pleistocene interglacials. The lower aminozone (−17.4 to −33 m MSL) spans an interval that probably includes at least two interglacials (based upon faunal and floral records) and has an age estimated to be between 800,000 and 1,300,000 yr. Boundaries delineated by faunal, floral, and amino acid methods do not always coincide, due to sampling constraints and phase lags between the different records. One major unconformity (at −17.4 m MSL) in the Stetson Pit section is easily recognized from lithologic characteristics and may represent a hiatus of as much as 800,000 yr. Lithologic changes associated with all other zone boundaries are subtle and would probably not be considered significant in the absence of faunal, floral, or amino acid data.
","language":"English","publisher":"Elsevier","doi":"10.1016/0031-0182(89)90136-3","issn":"00310182","usgsCitation":"York, L., Wehmiller, J., Cronin, T.M., and Ager, T.A., 1989, Stetson Pit, Dare County, North Carolina: An integrated chronologic, faunal, and floral record of subsurface coastal quaternary sediments: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 72, p. 115-132, https://doi.org/10.1016/0031-0182(89)90136-3.","productDescription":"18 p.","startPage":"115","endPage":"132","costCenters":[],"links":[{"id":224012,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"North Carolina","county":"Dare County","otherGeospatial":"Stetson Pit","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -75.84863392437401,\n 35.90063411778975\n ],\n [\n -75.84863392437401,\n 35.836059573229306\n ],\n [\n -75.78453889222824,\n 35.836059573229306\n ],\n [\n -75.78453889222824,\n 35.90063411778975\n ],\n [\n -75.84863392437401,\n 35.90063411778975\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"72","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b983be4b08c986b31beff","contributors":{"authors":[{"text":"York, L.L.","contributorId":58401,"corporation":false,"usgs":true,"family":"York","given":"L.L.","email":"","affiliations":[],"preferred":false,"id":369773,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wehmiller, J.F.","contributorId":37891,"corporation":false,"usgs":false,"family":"Wehmiller","given":"J.F.","email":"","affiliations":[],"preferred":false,"id":369771,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Cronin, T. M. 0000-0002-2643-0979","orcid":"https://orcid.org/0000-0002-2643-0979","contributorId":42613,"corporation":false,"usgs":true,"family":"Cronin","given":"T.","email":"","middleInitial":"M.","affiliations":[{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"preferred":false,"id":369772,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ager, T. A.","contributorId":88386,"corporation":false,"usgs":true,"family":"Ager","given":"T.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":369774,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70015594,"text":"70015594 - 1989 - Subduction of the Daiichi Kashima Seamount in the Japan trench","interactions":[],"lastModifiedDate":"2025-08-20T16:04:38.161889","indexId":"70015594","displayToPublicDate":"2003-03-27T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3525,"text":"Tectonophysics","active":true,"publicationSubtype":{"id":10}},"title":"Subduction of the Daiichi Kashima Seamount in the Japan trench","docAbstract":"In 1984-1985, the Kaiko consortium collected Seabeam, single-channel seismic and submersible sampling data in the vicinity of the Daiichi-Kashima seamount and the southern Japan trench. We performed a prestack migration of a Shell multichannel seismic profile, that crosses this area, and examined it in the light of this unusually diverse Kaiko dataset. Unlike the frontal structure of the northern Japan trench, where mass-wasting appears to be the dominant tectonic process, the margin in front of the Daiichi-Kashima shows indentation, imbrication, uplift and erosion. Emplacement of the front one-third of the seamount beneath the margin front occurs without accretion. We conclude that the Daiichi-Kashima seamount exemplifies an intermediate stage between the initial collision and subduction of a seamount at a continental margin.
","language":"English","publisher":"Elsevier","doi":"10.1016/0040-1951(89)90393-4","issn":"00401951","usgsCitation":"Lallemand, S., Culotta, R., and von Huene, R.E., 1989, Subduction of the Daiichi Kashima Seamount in the Japan trench: Tectonophysics, v. 160, no. 1-4, p. 237-247, https://doi.org/10.1016/0040-1951(89)90393-4.","productDescription":"11 p.","startPage":"237","endPage":"247","costCenters":[],"links":[{"id":224105,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Japan","otherGeospatial":"Daiichi Kashima","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n 138.85496532918535,\n 36.519758676508644\n ],\n [\n 138.85496532918535,\n 35.26197948632307\n ],\n [\n 141.09421405790607,\n 35.26197948632307\n ],\n [\n 141.09421405790607,\n 36.519758676508644\n ],\n [\n 138.85496532918535,\n 36.519758676508644\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"160","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9d0fe4b08c986b31d60b","contributors":{"authors":[{"text":"Lallemand, S.","contributorId":99703,"corporation":false,"usgs":true,"family":"Lallemand","given":"S.","email":"","affiliations":[],"preferred":false,"id":371323,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Culotta, Ray","contributorId":97254,"corporation":false,"usgs":true,"family":"Culotta","given":"Ray","affiliations":[],"preferred":false,"id":371322,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"von Huene, Roland E. 0000-0003-1301-3866 rvonhuene@usgs.gov","orcid":"https://orcid.org/0000-0003-1301-3866","contributorId":191070,"corporation":false,"usgs":true,"family":"von Huene","given":"Roland","email":"rvonhuene@usgs.gov","middleInitial":"E.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true},{"id":7065,"text":"USGS emeritus","active":true,"usgs":false}],"preferred":false,"id":371321,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":29572,"text":"wri884141 - 1989 - Assessment of processes affecting low-flow water quality of Cedar Creek, west-central Illinois","interactions":[],"lastModifiedDate":"2012-02-02T00:09:03","indexId":"wri884141","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":342,"text":"Water-Resources Investigations Report","code":"WRI","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"88-4141","title":"Assessment of processes affecting low-flow water quality of Cedar Creek, west-central Illinois","docAbstract":"Water quality and the processes that affect dissolved oxygen, nutrient (nitrogen and phosphorus species), and algal concentrations were evaluated for a 23.8-mile reach of Cedar Creek near Galesburg, west-central Illinois, during periods of warm-weather, low-flow conditions. Water quality samples were collected and stream conditions were measured over a diel (24 hour) period on three occasions during July and August 1985. Analysis of data from the diel-sampling periods indicates that concentrations of iron, copper, manganese, phenols, and total dissolved-solids exceeded Illinois ' general-use water quality standards in some locations. Dissolved-oxygen concentrations were less than the State minimum standard throughout much of the study reach. These data were used to calibrate and verify a one-dimensional, steady-state, water quality model. The computer model was used to assess the relative effects on low-flow water quality of processes such as algal photosynthesis and respiration, ammonia oxidation, biochemical oxygen demand, sediment oxygen demand, and stream reaeration. Results from model simulations and sensitivity analysis indicate that sediment oxygen demand is the principal cause of low dissolved-oxygen concentrations in the creek. (USGS)","language":"ENGLISH","publisher":"U.S. Geological Survey,","doi":"10.3133/wri884141","usgsCitation":"Schmidt, A.R., Freeman, W., and McFarlane, R., 1989, Assessment of processes affecting low-flow water quality of Cedar Creek, west-central Illinois: U.S. Geological Survey Water-Resources Investigations Report 88-4141, ix, 70 p. :ill., maps ;28 cm., https://doi.org/10.3133/wri884141.","productDescription":"ix, 70 p. :ill., maps ;28 cm.","costCenters":[],"links":[{"id":2390,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://il.water.usgs.gov/pubsearch/reports.cgi/view?series=WRIR&number=88-4141","linkFileType":{"id":5,"text":"html"}},{"id":126716,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/wri/1988/4141/report-thumb.jpg"},{"id":58400,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/wri/1988/4141/report.pdf","linkFileType":{"id":1,"text":"pdf"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4abae4b07f02db671ed3","contributors":{"authors":[{"text":"Schmidt, Arthur R.","contributorId":105709,"corporation":false,"usgs":true,"family":"Schmidt","given":"Arthur","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":201740,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Freeman, W.O.","contributorId":30238,"corporation":false,"usgs":true,"family":"Freeman","given":"W.O.","email":"","affiliations":[],"preferred":false,"id":201739,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"McFarlane, R.D.","contributorId":105728,"corporation":false,"usgs":true,"family":"McFarlane","given":"R.D.","email":"","affiliations":[],"preferred":false,"id":201741,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":3540,"text":"cir1050 - 1989 - The United States Geological Survey: 1879-1989","interactions":[],"lastModifiedDate":"2024-06-20T12:00:12.241407","indexId":"cir1050","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":307,"text":"Circular","code":"CIR","onlineIssn":"2330-5703","printIssn":"1067-084X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"1050","title":"The United States Geological Survey: 1879-1989","docAbstract":"The United States Geological Survey was established on March 3, 1879, just a few hours before the mandatory close of the final session of the 45th Congress, when President Rutherford B. Hayes signed the bill appropriating money for sundry civil expenses of the Federal Government for the fiscal year beginning July 1, 1879. The sundry civil expenses bill included a brief section establishing a new agency, the United States Geological Survey, placing it in the Department of the Interior, and charging it with a unique combination of responsibilities: 'classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain.' The legislation stemmed from a report of the National Academy of Sciences, which in June 1878 had been asked by Congress to provide a plan for surveying the Territories of the United States that would secure the best possible results at the least possible cost. Its roots, however, went far back into the Nation's history. The first duty enjoined upon the Geological Survey by the Congress, the classification of the public lands, originated in the Land Ordinance of 1785. The original public lands were the lands west of the Allegheny Mountains claimed by some of the colonies, which became a source of contention in writing the Articles of Confederation until 1781 when the States agreed to cede their western lands to Congress. The extent of the public lands was enormously increased by the Louisiana Purchase in 1803 and later territorial acquisitions. At the beginning of Confederation, the decision was made not to hold the public lands as a capital asset, but to dispose of them for revenue and to encourage settlement. The Land Ordinance of 1785 provided the method of surveying and a plan for disposal of the lands, but also reserved 'one-third part of all gold, silver, lead, and copper mines to be sold or otherwise disposed of, as Congress shall thereafter direct,' thus implicitly requiring classification of the lands into mineral and nonmineral. Mapping of the public lands was begun under the direction of the Surveyor-General, but no special provision was made for classification of the public lands, and it thus became the responsibility of the surveyor. There was,of course, no thought in 1785 or for many years thereafter of employing geologists to make the classification of the mineral lands, for geology was then only in its infancy.
","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/cir1050","usgsCitation":"Rabbitt, M.C., 1989, The United States Geological Survey: 1879-1989: U.S. Geological Survey Circular 1050, v, 52 p., https://doi.org/10.3133/cir1050.","productDescription":"v, 52 p.","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":366,"text":"Library","active":true,"usgs":true},{"id":37226,"text":"Core Science Analytics, Synthesis, and Libraries","active":true,"usgs":true}],"links":[{"id":430386,"rank":4,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/circ/c1050/index.htm","text":"Report","linkFileType":{"id":5,"text":"html"},"description":"CIR 1050 HTML"},{"id":117473,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/cir_1050.jpg"},{"id":312328,"rank":3,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/circ/1050/pdf/CIRC1050.pdf","text":"Report","size":"12.1 MB","linkFileType":{"id":1,"text":"pdf"},"description":"CIR 1050 PDF"},{"id":13662,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/circ/1050/","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4abce4b07f02db67348b","contributors":{"authors":[{"text":"Rabbitt, Mary C.","contributorId":94242,"corporation":false,"usgs":true,"family":"Rabbitt","given":"Mary","email":"","middleInitial":"C.","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":147125,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":27390,"text":"wri894097 - 1989 - Methodology, results, and significance of an unsaturated-zone tracer test at an artificial-recharge facility, Tucson, Arizona","interactions":[],"lastModifiedDate":"2012-02-02T00:08:39","indexId":"wri894097","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":342,"text":"Water-Resources Investigations Report","code":"WRI","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"89-4097","title":"Methodology, results, and significance of an unsaturated-zone tracer test at an artificial-recharge facility, Tucson, Arizona","docAbstract":"A tracer test conducted in 1987 at an artificial-recharge facility in Tucson, Arizona, indicates that solute movement through the poorly sorted stratified alluvial sediments in the unsaturated zone beneath a recharge basin takes place along preferential-flow paths. Movement of a tracer-laced pulse of reclaimed wastewater was monitored using pressure-vacuum lysimeters installed at depths that range from 11 to 45 ft below the bottom of the recharge basin. Tracer-breakthrough curves do not indicate a consistent relation between maximum tracer concentration and depth or between time of tracer breakthrough and depth. Apparent dispersion, as indicated by the slope of the rising leg of the tracer-breakthrough curve, shows no apparent relation with depth. In some cases, the tracer arrived earlier at deep sampling locations than at shallow ones. Velocity of solute flow ranged from 1.9 to 9.0 ft/day. Less interaction between recharge water and solid-phase materials in the unsaturated zone occurs under preferential-flow conditions than if flow occurred as a uniform wetting front. Flow of water through the unsaturated zone is concentrated into fingers or channels under preferential-flow conditions, and the renovating capability of soil is reduced because of the reduced surface area and reduced contact time in the biologically active part of the unsaturated profile. Chemical substances that normally would be decomposed by microbial activity or sorbed by sediment particles can move through the unsaturated zone and cause groundwater contamination under preferential-flow conditions. (USGS)","language":"ENGLISH","publisher":"U.S. Geological Survey ;\r\nBooks and Open-File Reports [distributor],","doi":"10.3133/wri894097","usgsCitation":"Graham, D., 1989, Methodology, results, and significance of an unsaturated-zone tracer test at an artificial-recharge facility, Tucson, Arizona: U.S. Geological Survey Water-Resources Investigations Report 89-4097, iv, 28 p. :ill. ;28 cm., https://doi.org/10.3133/wri894097.","productDescription":"iv, 28 p. :ill. ;28 cm.","costCenters":[],"links":[{"id":119965,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/wri/1989/4097/report-thumb.jpg"},{"id":56253,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/wri/1989/4097/report.pdf","linkFileType":{"id":1,"text":"pdf"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a51e4b07f02db62a02b","contributors":{"authors":[{"text":"Graham, D. D.","contributorId":68314,"corporation":false,"usgs":true,"family":"Graham","given":"D. D.","affiliations":[],"preferred":false,"id":198033,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70015273,"text":"70015273 - 1989 - Boron isotope evidence for the involvement of non-marine evaporites in the origin of the Broken Hill ore deposits","interactions":[],"lastModifiedDate":"2025-05-30T17:02:49.976245","indexId":"70015273","displayToPublicDate":"1989-12-28T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2840,"text":"Nature","active":true,"publicationSubtype":{"id":10}},"title":"Boron isotope evidence for the involvement of non-marine evaporites in the origin of the Broken Hill ore deposits","docAbstract":"Identifying the palaeogeographic setting and mode of origin of stratabound ore deposits can be difficult in high-grade metamorphic terranes, where the effects of metamorphism may obscure the nature of the protoliths. Here we report boron isotope data for tourmalines from the early Proterozoic Broken Hill block, in Australia, which hosts giant lead-zinc-silver sulphide deposits. With one exception the 11B/10B ratios are lower than those for all other tourmalines from massive sulphide deposits and tour-malinites elsewhere in the world. We propose that these low ratios reflect leaching of boron from non-marine evaporitic borates by convecting hydrothermal fluids associated with early Proterozoic continental rifting. A possible modern analogue is the Salton Sea geothermal field in California.
","language":"English","publisher":"Springer Nature","doi":"10.1038/342913a0","issn":"00280836","usgsCitation":"Slack, J.F., Palmer, M.R., and Stevens, B., 1989, Boron isotope evidence for the involvement of non-marine evaporites in the origin of the Broken Hill ore deposits: Nature, v. 342, no. 6252, p. 913-916, https://doi.org/10.1038/342913a0.","productDescription":"4 p.","startPage":"913","endPage":"916","costCenters":[],"links":[{"id":223924,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"342","issue":"6252","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f220e4b0c8380cd4b00b","contributors":{"authors":[{"text":"Slack, J. F.","contributorId":75917,"corporation":false,"usgs":true,"family":"Slack","given":"J.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":370516,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Palmer, M. R.","contributorId":81256,"corporation":false,"usgs":true,"family":"Palmer","given":"M.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":370517,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Stevens, B.P.J.","contributorId":61173,"corporation":false,"usgs":true,"family":"Stevens","given":"B.P.J.","email":"","affiliations":[],"preferred":false,"id":370515,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70210210,"text":"70210210 - 1989 - Crustal structure of the Chugach Mountains, southern Alaska: A study of peg‐leg multiples from a low‐velocity zone","interactions":[],"lastModifiedDate":"2020-05-20T15:33:32.777701","indexId":"70210210","displayToPublicDate":"1989-11-10T10:24:29","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2314,"text":"Journal of Geophysical Research B: Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Crustal structure of the Chugach Mountains, southern Alaska: A study of peg‐leg multiples from a low‐velocity zone","docAbstract":"A seismic refraction profile recorded along the geologic strike of the Chugach Mountains in southern Alaska shows three upper crustal high‐velocity layers (6.9, 7.2, and 7.6 km/s) and a unique pattern of strongly focussed echelon arrivals to a distance of 225 km. The group velocity of the ensemble of echelon arrivals is 6.4 km/s. Modeling of this profile with the reflectivity method reveals that the echelon pattern is due to peg‐leg multiples generated from within a low‐velocity zone between the second and third upper crustal high‐velocity layers. The third high‐velocity layer (7.6 km/s) is underlain at 18 km depth by a pronounced low‐velocity zone that produces a seismic shadow zone wherein peg‐leg multiples are seen as echelon arrivals. The interpretation of these echelon arrivals as multiples supersedes an earlier interpretation which attributed them to successive primary reflections arising from alternating high‐ and low‐velocity layers. Synthetic seismogram modeling indicates that a low‐velocity zone with transitional upper and lower boundaries generates peg‐leg multiples as effectively as one with sharp boundaries. No PmP or Pn arrivals from the subducting oceanic Moho at 30 km depth beneath the western part of the line are observed on the long‐offset (90–225 km) data. This may be due to a lower crustal waveguide whose top is the high‐velocity (7.6 km/s) layer and whose base is the Moho. A deep (∼54 km) reflector is not affected by the waveguide and has been identified in the data. Although peg‐leg multiples have been interpreted on some long‐range refraction profiles that sound to upper mantle depths, the Chugach Mountains profile is one of the few crustal refraction profiles where peg‐leg multiples are clearly observed. This study indicates that multiple and converted phases may be more important in seismic refraction/wide‐angle reflection profiles than previously recognized.
Peak accelerations of the Loma Prieta main shock have been tabulated from instruments maintained by a number of organizations. We have analyzed a subset of 86 records from nominally free-field sites, which have been subdivided into rock, alluvium, and bay-mud categories according to data available in various reports. After correction for attenuation, the peak accelerations on rock, alluvium, and bay-mud sites are factors of 1.6, 1.8, and 4.5 larger, on the average, than Joyner and Boore’s (1988) predicted values for a M= 6.9 earthquake. The mean motions for the rock and alluvium sites are somewhat greater than one standard deviation away from the predicted value, but the mean acceleration from the bay-mud sites is well outside the range expected from analyses of data from previous earthquakes from rock and alluvium sites. Large amplitudes of motions on bay-mud sites relative to rock sites (a factor of 2.8 for the average of the recordings of the Loma Prieta main shock) has been found previously from recordings of distant earthquakes and explosions, but the Loma Prieta earthquake provided the first opportunity to study the relative amplitudes from strong-motion recordings.
","language":"English","publisher":"GeoScienceWorld","doi":"10.1785/gssrl.60.4.151","issn":"08950695","usgsCitation":"Boore, D., Seekins, L., and Joyner, W.B., 1989, Peak accelerations from the 17 October 1989 Loma Prieta earthquake: Seismological Research Letters, v. 60, no. 4, p. 151-166, https://doi.org/10.1785/gssrl.60.4.151.","productDescription":"16 p.","startPage":"151","endPage":"166","costCenters":[],"links":[{"id":223705,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -123.17540901474337,\n 38.544096283987756\n ],\n [\n -123.17540901474337,\n 36.52712218016232\n ],\n [\n -119.98531055812316,\n 36.52712218016232\n ],\n [\n -119.98531055812316,\n 38.544096283987756\n ],\n [\n -123.17540901474337,\n 38.544096283987756\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"60","issue":"4","noUsgsAuthors":false,"publicationDate":"1989-10-01","publicationStatus":"PW","scienceBaseUri":"505a7605e4b0c8380cd77e9c","contributors":{"authors":[{"text":"Boore, D.M. 0000-0002-8605-9673","orcid":"https://orcid.org/0000-0002-8605-9673","contributorId":64226,"corporation":false,"usgs":true,"family":"Boore","given":"D.M.","affiliations":[],"preferred":false,"id":370480,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Seekins, Linda","contributorId":84751,"corporation":false,"usgs":true,"family":"Seekins","given":"Linda","affiliations":[],"preferred":false,"id":370479,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Joyner, W. B.","contributorId":70746,"corporation":false,"usgs":true,"family":"Joyner","given":"W.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":370481,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70123390,"text":"70123390 - 1989 - Logging in western Oregon: responses of headwater habitats and stream amphibians","interactions":[],"lastModifiedDate":"2017-11-21T16:48:17","indexId":"70123390","displayToPublicDate":"1989-09-01T10:44:49","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1687,"text":"Forest Ecology and Management","active":true,"publicationSubtype":{"id":10}},"title":"Logging in western Oregon: responses of headwater habitats and stream amphibians","docAbstract":"We compared occurrence and abundance of four species of aquatic amphibians in 23 streams flowing through uncut forests to 20 streams flowing through forests logged between 14 and 40 years prior to the study. Species richness was highest in streams in uncut forests. Eleven streams in uncut forests contained all four species, and only two of these streams had fewer than three species present. Eleven streams in logged stands had one or no species present, and only one contained all four species. Density and biomass of all four species were significantly greater (2–7 X) in streams in uncut forests. Physical comparisons between types of streams were similar, except that streams in logged stands had generally smaller substrata, resulting from increased sedimentation. Densities of Pacific giant salamanders (Dicamptodon ensatus) and Olympic salamanders (Rhyacotriton olymoicus) were positively correlated with stream gradient in logged stands, but not in uncut forests, suggesting that the disruptive effects of increased sedimentation are greatest in low-gradient streams. Tailed frogs (Ascaphus truei) and Dunn's salamanders (Plethodon dunni) occurred more often in streams in logged stands when uncut timber was present upstream, but neither density nor biomass of any species were related to either presence of uncut timber upstream or years since logging. Logging upstream from uncut forests also had no effect on the presence, density or biomass of any species. Tailed frogs and Olympic salamanders may be extirpated from headwaters traversing clearcuts; these streams should be afforded some protection in plans for managed forests.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Forest Ecology and Management","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier Science","publisherLocation":"Amsterdam","doi":"10.1016/0378-1127(89)90055-8","usgsCitation":"Corn, P., and Bury, R.B., 1989, Logging in western Oregon: responses of headwater habitats and stream amphibians: Forest Ecology and Management, v. 29, no. 1-2, p. 39-57, https://doi.org/10.1016/0378-1127(89)90055-8.","productDescription":"19 p.","startPage":"39","endPage":"57","numberOfPages":"19","costCenters":[],"links":[{"id":293369,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":293368,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0378-1127(89)90055-8"}],"country":"United States","state":"Oregon","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -124.6129,41.9918 ], [ -124.6129,46.292 ], [ -116.4633,46.292 ], [ -116.4633,41.9918 ], [ -124.6129,41.9918 ] ] ] } } ] }","volume":"29","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"542a74f9e4b01535cb4278cb","contributors":{"authors":[{"text":"Corn, Paul Stephen 0000-0002-4106-6335","orcid":"https://orcid.org/0000-0002-4106-6335","contributorId":107379,"corporation":false,"usgs":true,"family":"Corn","given":"Paul Stephen","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":500069,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bury, R. Bruce buryb@usgs.gov","contributorId":3660,"corporation":false,"usgs":true,"family":"Bury","given":"R.","email":"buryb@usgs.gov","middleInitial":"Bruce","affiliations":[{"id":290,"text":"Forest and Rangeland Ecosystem Science Center","active":false,"usgs":true}],"preferred":false,"id":500068,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":5222246,"text":"5222246 - 1989 - Comparative toxicity of lead shot in black ducks (Anas rubripes) and mallards (Anas platyrhynchos)","interactions":[],"lastModifiedDate":"2020-05-12T16:15:14.180526","indexId":"5222246","displayToPublicDate":"1989-06-16T12:19:06","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2507,"text":"Journal of Wildlife Diseases","active":true,"publicationSubtype":{"id":10}},"displayTitle":"Comparative toxicity of lead shot in black ducks (Anas rubripes) and mallards (Anas platyrhynchos)","title":"Comparative toxicity of lead shot in black ducks (Anas rubripes) and mallards (Anas platyrhynchos)","docAbstract":"In winter, pen-reared and wild black ducks (Anas rubripes), and game farm and wild mallards (Anas platyrhynchos), maintained on pelleted feed, were sham-dosed or given one number 4 lead shot. After 14 days, dosed birds were redosed with two or four additional lead shot. This dosing regimen also was repeated in summer using pen-reared black ducks and game farm mallards. Based upon mortality, overt intoxication, weight change, delta-aminolevulinic acid dehydratase activity and protoporphyrin concentration, black ducks and mallards were found to be equally tolerant to lead shot. However, captive wild ducks were more sensitive than their domesticated counterparts, as evidenced by greater mortality and weight loss following lead shot administration. This difference may be related to stress associated with captivity and unnatural diet.
","largerWorkTitle":"","language":"English","publisher":"Wildlife Disease Association","doi":"10.7589/0090-3558-25.2.175","usgsCitation":"Rattner, B., Fleming, W.J., and Bunck, C., 1989, Comparative toxicity of lead shot in black ducks (Anas rubripes) and mallards (Anas platyrhynchos): Journal of Wildlife Diseases, v. 25, no. 2, p. 175-183, https://doi.org/10.7589/0090-3558-25.2.175.","productDescription":"9 p.","startPage":"175","endPage":"183","numberOfPages":"9","costCenters":[{"id":531,"text":"Patuxent Wildlife Research Center","active":true,"usgs":true}],"links":[{"id":194114,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"25","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b24e4b07f02db6ae4bd","contributors":{"authors":[{"text":"Rattner, Barnett A. 0000-0003-3676-2843","orcid":"https://orcid.org/0000-0003-3676-2843","contributorId":95843,"corporation":false,"usgs":true,"family":"Rattner","given":"Barnett A.","affiliations":[{"id":50464,"text":"Eastern Ecological Science Center","active":true,"usgs":true}],"preferred":true,"id":335900,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fleming, W. James","contributorId":85279,"corporation":false,"usgs":true,"family":"Fleming","given":"W.","email":"","middleInitial":"James","affiliations":[],"preferred":false,"id":335899,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bunck, C.M.","contributorId":72337,"corporation":false,"usgs":true,"family":"Bunck","given":"C.M.","email":"","affiliations":[],"preferred":false,"id":335898,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70210577,"text":"70210577 - 1989 - The crustal structure of the Wrangellia Terrane along the East Glenn Highway, eastern‐southern Alaska","interactions":[],"lastModifiedDate":"2020-06-10T16:51:12.301168","indexId":"70210577","displayToPublicDate":"1989-06-10T11:42:19","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2314,"text":"Journal of Geophysical Research B: Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"The crustal structure of the Wrangellia Terrane along the East Glenn Highway, eastern‐southern Alaska","docAbstract":"Recently acquired seismic refraction data from eastern‐southern Alaska provide new information on the structure and composition of the Wrangellia and adjacent terranes. The data comprise a 160‐km‐long refraction profile along the East Glenn (Tok‐Cutoff) Highway that was collected as part of the U.S. Geological Survey's multidisciplinary Trans‐Alaska Crustal Transect program. The upper 3 km of the Wrangellia terrane and associated rocks is characterized by low compressional wave velocities (Vp = 1.9, 3.3, 4.6, 5.6 km s−1) and high‐velocity gradients common to most onshore seismic refraction profiles. There is also clear seismic expression of the West Fork fault system as a steep, down‐to‐the‐southwest fault that separates the Peninsular terrane to the southwest and the metamorphic complex of Gulkana River to the northeast. In contrast, no seismic expression occurs for the Paxson Lake fault, which separates the Wrangellia terrane from the metamorphic complex of Gulkana River. Adjacent to the Denali fault, within the Wrangellia terrane, two high‐velocity bodies (Vp = 6.6 km s−1) occur in the upper crust. One of these extends to ∼10‐km depth and correlates with a late Paleozoic dioritic complex, suggesting that the Wrangellia terrane is at least 10 km thick in this part of Alaska. From 5 to 23 km depth, the crust appears seismically homogeneous, with velocity increasing from Vp = 6.2 to Vp = 6.6 km s−1. Beneath this level, the crust is less well resolved, although evidence exists for a low‐velocity zone between 23 and 26 km and a possible southwest dipping interface at 35 km. No identifiable mantle refraction or reflection is observed, possibly indicating a crust as thick as 55 km. The relatively low seismic velocities in the upper 23 km of the crust compare favorably with laboratory‐measured velocities on pelitic schists and intermediate‐composition plutonic rocks (granites and granodiorites), both of which are recognized in Wrangellia. We interpret the seismic velocities to indicate that silicic‐to‐intermediate‐composition rocks are important constituents of the basement of this part of Wrangellia. Geologic evidence indicates that the Alaskan part of the Wrangellia terrane is a Paleozoic and Mesozoic island arc: our seismic evidence indicates it may have been built mostly on continental crust as opposed to the fragment of Wrangellia from Vancouver Island which was probably built on oceanic crust.
","language":"English","publisher":"Wiley","doi":"10.1029/JB094iB11p16037","usgsCitation":"Goodwin, E., Fuis, G.S., Nokleberg, W.J., and Ambos, E.L., 1989, The crustal structure of the Wrangellia Terrane along the East Glenn Highway, eastern‐southern Alaska: Journal of Geophysical Research B: Solid Earth, v. 94, no. B11, p. 16037-16057, https://doi.org/10.1029/JB094iB11p16037.","productDescription":"21 p.","startPage":"16037","endPage":"16057","costCenters":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"links":[{"id":375494,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Alaska","otherGeospatial":"Eastern- Southern Alaska","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -153.28125,\n 57.51582286553883\n ],\n [\n -132.1875,\n 57.51582286553883\n ],\n [\n -132.1875,\n 64.51064316846676\n ],\n [\n -153.28125,\n 64.51064316846676\n ],\n [\n -153.28125,\n 57.51582286553883\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"94","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","contributors":{"authors":[{"text":"Goodwin, E.B.","contributorId":225177,"corporation":false,"usgs":false,"family":"Goodwin","given":"E.B.","email":"","affiliations":[],"preferred":false,"id":790653,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fuis, Gary S. 0000-0002-3078-1544 fuis@usgs.gov","orcid":"https://orcid.org/0000-0002-3078-1544","contributorId":2639,"corporation":false,"usgs":true,"family":"Fuis","given":"Gary","email":"fuis@usgs.gov","middleInitial":"S.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":790654,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Nokleberg, Warren J. 0000-0002-1574-8869 wnokleberg@usgs.gov","orcid":"https://orcid.org/0000-0002-1574-8869","contributorId":2077,"corporation":false,"usgs":true,"family":"Nokleberg","given":"Warren","email":"wnokleberg@usgs.gov","middleInitial":"J.","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":true,"id":790655,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ambos, E. L.","contributorId":23957,"corporation":false,"usgs":true,"family":"Ambos","given":"E.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":790656,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70233980,"text":"70233980 - 1989 - An exact anelastic model for the free-surface reflection of P and S-I waves","interactions":[],"lastModifiedDate":"2022-07-28T14:35:02.878483","indexId":"70233980","displayToPublicDate":"1989-06-01T09:28:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1135,"text":"Bulletin of the Seismological Society of America","onlineIssn":"1943-3573","printIssn":"0037-1106","active":true,"publicationSubtype":{"id":10}},"displayTitle":"An exact anelastic model for the free-surface reflection of P and S-I waves","title":"An exact anelastic model for the free-surface reflection of P and S-I waves","docAbstract":"Exact anelastic solutions incorporating inhomogeneous waves are used to model numerically S-I and P waves incident on the free surface of a low-loss anelastic half-space. Anelastic free-surface reflection coefficients are computed for the volumetric strain and displacement components of inhomogeneous wave fields. For the problem of an incident homogeneous S-I wave in Pierre shale, the largest strain and displacement amplitudes for the reflected P wave occur at angles of incidence for which the particle motion for the reflected inhomogeneous P wave is elliptical (minor/major axis = 0.6), the specific absorption (QP−1) is greater (300 per cent) and the velocity is less (25 per cent) than those for a corresponding homogeneous P wave, the direction of phase propagation is not parallel to the free surface, and the amplitude of the wave shows a significant increase with depth (6 per cent in one wavelength). Energy reflection coefficients computed for this low-loss anelastic model show that energy flow due to interaction of the incident and reflected waves reach maxima (30 per cent of the incident energy) near large but nongrazing angles of incidence. For the problem of an incident homogeneous P wave in Pierre shale, the inhomogeneity of the reflected S wave is shown not to contribute to significant variations in wave field characteristics over those that would be expected for a homogeneous wave.
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0790030842","usgsCitation":"Borcherdt, R.D., and Glassmoyer, G., 1989, An exact anelastic model for the free-surface reflection of P and S-I waves: Bulletin of the Seismological Society of America, v. 79, no. 3, p. 842-859, https://doi.org/10.1785/BSSA0790030842.","productDescription":"18 p.","startPage":"842","endPage":"859","costCenters":[{"id":234,"text":"Earthquake Hazards Program","active":true,"usgs":true}],"links":[{"id":404543,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"79","issue":"3","noUsgsAuthors":false,"publicationDate":"1989-06-01","publicationStatus":"PW","contributors":{"authors":[{"text":"Borcherdt, Roger D. 0000-0002-8668-0849 borcherdt@usgs.gov","orcid":"https://orcid.org/0000-0002-8668-0849","contributorId":2373,"corporation":false,"usgs":true,"family":"Borcherdt","given":"Roger","email":"borcherdt@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":847766,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Glassmoyer, G.","contributorId":62751,"corporation":false,"usgs":true,"family":"Glassmoyer","given":"G.","email":"","affiliations":[],"preferred":false,"id":847767,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70015421,"text":"70015421 - 1989 - Application of the Graphic Correlation method to Pliocene marine sequences","interactions":[],"lastModifiedDate":"2024-10-02T16:44:51.289376","indexId":"70015421","displayToPublicDate":"1989-05-01T00:00:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2673,"text":"Marine Micropaleontology","active":true,"publicationSubtype":{"id":10}},"title":"Application of the Graphic Correlation method to Pliocene marine sequences","docAbstract":"A new isostatic residual gravity map of the conterminous United States presents continent-wide gravity data in a form that can be readily used, with geologic information and other geophysical data, in studies of the composition and structure of the continental crust. This map was produced from the gridded gravity data on which the recently released Gravity Anomaly Map of the United States is based. About 1 million onland and 0.8 million offshore gravity observations interpolated to a 4- by 4-km grid serve as the basis for both maps. The Airy-Heiskanen model of isostatic compensation of topography applied to topographic and bathymetric data averaged over 5- by 5-min compartments was used to remove, to first order, the large, long-wavelength Bouguer gravity anomalies caused by deep density distributions that support topographic loads. The parameters used in the Airy-Heiskanen model were topographic density, 2.67 g/cm3; sea-level crustal thickness, 30 km; and density contrast across the base of the model crust, 0.35 g/cm3.
Many of the conspicuous short-wavelength anomalies (widths less than several hundred kilometers) on the isostatic residual gravity map correlate with mapped or near-surface geologic features, and primarily reflect shallow-density distributions rather than any departures from isostatic equilibrium. In general, gravity highs occur over (1) mafic igneous bodies emplaced in rift or magmatic arc settings or as isolated intrusions controlled by structures; (2) accreted slices of mafic oceanic, island-arc, or transitional crust; and (3) uplifted crystalline basement. Gravity lows are found over (1) thick bodies of felsic intrusive or extrusive rocks; (2) sedimentary deposits in extensional, convergent, or transform settings; and (3) depressed crystalline basement. Anomalies with widths as much as 1,000 km or more also appear to reflect crustal properties in many cases—several broad gravity highs are associated with crust having a high average seismic wave velocity, and comparable broad gravity lows occur over areas of low average seismic velocity.
Alternative ways of viewing the isostatic residual gravity data provide additional information about density distributions in the crust. The first-vertical derivative map accentuates gravity anomalies over shallow, abrupt density changes at the expense of those resulting from deeper or more gradual density transitions. The maximum horizontal gradient map contains information about the locations of pronounced density boundaries. Two-dimensional spectral analysis of the gravity data provides a quantitative means for identifying dominant fabrics in the gravity field and for distinguishing various terranes from each other.
Neither Bouguer nor isostatic residual gravity anomalies are particularly well suited for practical modeling of deep structure in conjunction with deep seismic information. However, a scheme in which the entire Earth outside the area of interest is approximated by laterally homogeneous layers and isostatically compensated topography, and in which the area of interest is modeled using the seismic constraints applied in a two-and-one-half-dimensional geometry, holds promise for exploiting useful features of both the Bouguer and isostatic residual gravity anomalies.
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simpson@usgs.gov","contributorId":1053,"corporation":false,"usgs":true,"family":"Simpson","given":"Robert","email":"simpson@usgs.gov","middleInitial":"W.","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":true,"id":788085,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blakely, Richard J. 0000-0003-1701-5236 blakely@usgs.gov","orcid":"https://orcid.org/0000-0003-1701-5236","contributorId":1540,"corporation":false,"usgs":true,"family":"Blakely","given":"Richard","email":"blakely@usgs.gov","middleInitial":"J.","affiliations":[{"id":662,"text":"Western Mineral and Environmental Resources Science Center","active":true,"usgs":true},{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":true,"id":788086,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Saltus, Richard W. saltus@usgs.gov","contributorId":777,"corporation":false,"usgs":true,"family":"Saltus","given":"Richard","email":"saltus@usgs.gov","middleInitial":"W.","affiliations":[{"id":211,"text":"Crustal Geophysics and Geochemistry Science Center","active":true,"usgs":true}],"preferred":true,"id":788087,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70123399,"text":"70123399 - 1989 - Leopard frog and wood frog reproduction in Colorado and Wyoming","interactions":[],"lastModifiedDate":"2014-09-04T11:25:00","indexId":"70123399","displayToPublicDate":"1989-04-01T11:21:00","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2901,"text":"Northwestern Naturalist","active":true,"publicationSubtype":{"id":10}},"title":"Leopard frog and wood frog reproduction in Colorado and Wyoming","docAbstract":"Between 1978 and 1988, we recorded reproductive information from populations of ranid frogs in Colorado and Wyoming. Egg masses from five plains and montane populations of northern leopard frogs (Rana pipiens) contained 645-6272 eggs (x̄ = 3045, N = 68 egg masses). In two montane populations of wood frogs (Rana sylvatica) numbers of eggs per egg mass varied from 711-1248 (x̄ = 876, N = 15) and probably were equal to total clutch size. Mean hatching success was 90% in egg masses from one R. sylvatica population and ranged from 70% to 99% in R. pipiens egg masses. Rana pipiens egg masses from one location were assigned to three overlapping size distributions, which we believe reflects the underlying age structure of female frogs.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Northwestern Naturalist","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Society for Northwestern Vertebrate Biology","publisherLocation":"Olympia, WA","doi":"10.2307/3536918","usgsCitation":"Corn, P., and Livo, L.J., 1989, Leopard frog and wood frog reproduction in Colorado and Wyoming: Northwestern Naturalist, v. 70, no. 1, p. 1-9, https://doi.org/10.2307/3536918.","productDescription":"9 p.","startPage":"1","endPage":"9","numberOfPages":"9","costCenters":[],"links":[{"id":293382,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":293381,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.2307/3536918"}],"country":"United States","state":"Colorado;Wyoming","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -110.99,36.99 ], [ -110.99,44.96 ], [ -102.04,44.96 ], [ -102.04,36.99 ], [ -110.99,36.99 ] ] ] } } ] }","volume":"70","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"542a74f4e4b01535cb427880","contributors":{"authors":[{"text":"Corn, Paul Stephen 0000-0002-4106-6335","orcid":"https://orcid.org/0000-0002-4106-6335","contributorId":107379,"corporation":false,"usgs":true,"family":"Corn","given":"Paul Stephen","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":500083,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Livo, Lauren J.","contributorId":64578,"corporation":false,"usgs":true,"family":"Livo","given":"Lauren","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":500082,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70207745,"text":"70207745 - 1989 - Changes in redox conditions in deep‐sea sediments of the subarctic North Pacific Ocean: Possible evidence for the presence of North Pacific Deep Water","interactions":[],"lastModifiedDate":"2020-06-18T15:35:22.685121","indexId":"70207745","displayToPublicDate":"1989-01-09T10:34:57","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3002,"text":"Paleoceanography","active":true,"publicationSubtype":{"id":10}},"title":"Changes in redox conditions in deep‐sea sediments of the subarctic North Pacific Ocean: Possible evidence for the presence of North Pacific Deep Water","docAbstract":"Cores of upper Quaternary and Holocene sediment from the subarctic North Pacific north of about 48°N contain one or more layers of oxidized brown sediment interbedded within predominantly reduced green sediment. The brown layers are enriched in several trace elements, especially Mn, Mo, Ni, and Co, relative to the green layers. Where multiple oxidized layers are present, the intensity of the brown coloration and the magnitude of trace element enrichment often decrease with depth, suggesting that the oxidized layers are unstable and are being chemically reduced at depth. The oxidized layers represent a change in redox conditions between the North Pacific red clay province and the subarctic biosiliceous green clay province. The redox change may have been caused by an increase in supply of dissolved oxygen to bottom waters during glacial‐interglacial transitions as the result of the periodic formation of a seasonal bottom water mass in the northeastern Pacific Ocean.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/PA004i006p00639","usgsCitation":"Dean, W.E., Gardner, J.V., and Eileen Hemphill-Haley, 1989, Changes in redox conditions in deep‐sea sediments of the subarctic North Pacific Ocean: Possible evidence for the presence of North Pacific Deep Water: Paleoceanography, v. 4, no. 6, p. 639-653, https://doi.org/10.1029/PA004i006p00639.","productDescription":"15 p.","startPage":"639","endPage":"653","costCenters":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"links":[{"id":371104,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Alaska","otherGeospatial":"North Pacific Deep Water","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -163.65234374999997,\n 59.17592824927136\n ],\n [\n -183.515625,\n 54.77534585936447\n ],\n [\n -180.52734375,\n 47.635783590864854\n ],\n [\n -165.58593749999997,\n 47.989921667414194\n ],\n [\n -145.37109375,\n 49.95121990866204\n ],\n [\n -129.375,\n 48.922499263758255\n ],\n [\n -129.375,\n 53.12040528310657\n ],\n [\n -134.296875,\n 58.81374171570782\n ],\n [\n -146.07421875,\n 62.2679226294176\n ],\n [\n -163.65234374999997,\n 59.17592824927136\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"4","issue":"6","noUsgsAuthors":false,"publicationDate":"2010-05-04","publicationStatus":"PW","contributors":{"authors":[{"text":"Dean, Walter E. dean@usgs.gov","contributorId":1801,"corporation":false,"usgs":true,"family":"Dean","given":"Walter","email":"dean@usgs.gov","middleInitial":"E.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":779165,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gardner, J. V.","contributorId":114111,"corporation":false,"usgs":true,"family":"Gardner","given":"J.","email":"","middleInitial":"V.","affiliations":[],"preferred":false,"id":779166,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Eileen Hemphill-Haley","contributorId":206892,"corporation":false,"usgs":false,"family":"Eileen Hemphill-Haley","affiliations":[{"id":7067,"text":"Humboldt State University","active":true,"usgs":false}],"preferred":false,"id":779167,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70210207,"text":"70210207 - 1989 - Seismic methods for determining earthquake source parameters and lithospheric structure","interactions":[],"lastModifiedDate":"2020-05-20T14:46:31.850193","indexId":"70210207","displayToPublicDate":"1989-01-01T09:43:40","publicationYear":"1989","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1726,"text":"GSA Memoirs","active":true,"publicationSubtype":{"id":10}},"title":"Seismic methods for determining earthquake source parameters and lithospheric structure","docAbstract":"The seismologic methods most commonly used in studies of earthquakes and the structure of the continental lithosphere are reviewed in three main sections: earthquake source parameter determinations, the determination of earth structure using natural sources, and controlled-source seismology. The emphasis in each section is on a description of data, the principles behind the analysis techniques, and the assumptions and uncertainties in interpretation. Rather than focusing on future directions in seismology, the goal here is to summarize past and current practice as a companion to the review papers in this volume.
Reliable earthquake hypocenters and focal mechanisms require seismograph locations with a broad distribution in azimuth and distance from the earthquakes; a recording within one focal depth of the epicenter provides excellent hypocentral depth control. For earthquakes of magnitude greater than 4.5, waveform modeling methods may be used to determine source parameters. The seismic moment tensor provides the most complete and accurate measure of earthquake source parameters, and offers a dynamic picture of the faulting process.
Methods for determining the Earth’s structure from natural sources exist for local, regional, and teleseismic sources. One-dimensional models of structure are obtained from body and surface waves using both forward and inverse modeling. Forward-modeling methods include consideration of seismic amplitudes and waveforms, but lack the formal resolution estimates obtained with inverse methods. Two- and three-dimensional lithospheric models are derived using various inverse methods, but at present most of these methods consider only traveltimes of body waves.
Controlled-source studies of the Earth’s structure are generally divided by method into seismic refraction/wide-angle reflection and seismic reflection studies. Seismic refraction profiles are usually interpreted in terms of two-dimensional structure by forward modeling of traveltimes and amplitudes. The refraction method gives excellent estimates of seismic velocities, but relatively low resolution of structure. Formal resolution estimates are not possible for models derived from forward modeling, but informal estimates can be obtained by perturbing the best-fitting model. Inversion methods for seismic refraction data for one-dimensional models are well established, and two- and three-dimensional methods, including tomography, have recently been developed.
Seismic reflection data provide the highest resolution of crustal structure, and have provided many important geological insights in the past decade. The acquisition and processing of these data have been greatly advanced by the hydrocarbon exploration industry. However, reliable crustal velocity control is generally lacking, and the origin of deep crustal reflections remains unclear, resulting in nonunique interpretations. A new form of lithospheric seismology has recently emerged that combines the advantages of seismic refraction and seismic reflection profiles, and the distinction between the two methods is steadily diminishing.
Major challenges for future work will be the collection of data that are more densely sampled in space, and the development of interpretation methods that provide quantitative estimates of the uncertainties in the calculated models.
","language":"English","publisher":"Geological Society of America","doi":"10.1130/MEM172-p11","usgsCitation":"Mooney, W.D., 1989, Seismic methods for determining earthquake source parameters and lithospheric structure: GSA Memoirs, v. 172, p. 11-34, https://doi.org/10.1130/MEM172-p11.","productDescription":"24 p.","startPage":"11","endPage":"34","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":374962,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"172","noUsgsAuthors":false,"publicationDate":"1989-01-01","publicationStatus":"PW","contributors":{"authors":[{"text":"Mooney, Walter D. 0000-0002-5310-3631 mooney@usgs.gov","orcid":"https://orcid.org/0000-0002-5310-3631","contributorId":3194,"corporation":false,"usgs":true,"family":"Mooney","given":"Walter","email":"mooney@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":true,"id":789534,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}