The ground-water flow system in the Lower Susquehanna River Basin in Pennsylvania and Maryland can be considered as one complex unconfined aquifer in which secondary porosity and permeability are the dominant influences on the occurrence and flow of ground water. The degree of development of secondary porosity and permeability in the various lithologies of the lower basin determines the aquifer characteristics of each lithology. Based on qualitative evidence, the use of a porous-media model was assumed to be appropriate on a regional scale and a finite-difference ground-water flow model was constructed for the lower basin.
The conceptual model of ground-water flow in the lower basin incorporates the major features of the flow system. Through the use of two layers, 21 hydrogeologic units, and five topographic settings, the conceptual model was systematically reduced to arrive at a simplified conceptual model. Further reduction produced a numerical model representation of the conceptual model, in which the essential features of the lower-basin flow system were quantified for input into the numerical model.
The model was calibrated under both steady-state and transient conditions, and was used to evaluate the water-supply potential of the 21 hydrogeologic units. The carbonate units have the greatest potential for ground-water development and the Triassic sedimentary and crystalline units have the least potential. A total ground-water yield potential of about 900 million gallons per day could be obtained from the lower basin with a consequent 50-percent reduction of base flow in streams.
The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs.
","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Contributions to Mineralogy and Petrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF01150293","issn":"00107999","usgsCitation":"Bacon, C., Kurasawa, H., Delevaux, M., Kistler, R.W., and Doe, B.R., 1984, Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California: Contributions to Mineralogy and Petrology, v. 85, no. 4, p. 366-375, https://doi.org/10.1007/BF01150293.","productDescription":"10 p.","startPage":"366","endPage":"375","numberOfPages":"10","costCenters":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":221912,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205163,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF01150293"}],"volume":"85","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a45aee4b0c8380cd67478","contributors":{"authors":[{"text":"Bacon, C. R. 0000-0002-2165-5618","orcid":"https://orcid.org/0000-0002-2165-5618","contributorId":21522,"corporation":false,"usgs":true,"family":"Bacon","given":"C. R.","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":false,"id":364484,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kurasawa, H.","contributorId":41565,"corporation":false,"usgs":true,"family":"Kurasawa","given":"H.","email":"","affiliations":[],"preferred":false,"id":364487,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Delevaux, M.H.","contributorId":27853,"corporation":false,"usgs":true,"family":"Delevaux","given":"M.H.","email":"","affiliations":[],"preferred":false,"id":364485,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kistler, R. W.","contributorId":36112,"corporation":false,"usgs":true,"family":"Kistler","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":364486,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Doe, B. R.","contributorId":52173,"corporation":false,"usgs":true,"family":"Doe","given":"B.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":364488,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70013604,"text":"70013604 - 1984 - Modification of wave-cut and faulting-controlled landforms","interactions":[],"lastModifiedDate":"2024-06-27T16:24:22.78454","indexId":"70013604","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Modification of wave-cut and faulting-controlled landforms","docAbstract":"From a casual observation that the form of degraded fault scarps resembles the error function, this investigation proceeds through an elementary diffusion equation representation of landform evolution to the application of the resulting equations to the modern topography of scarplike landforms. The morphologic observations can be analyzed either in the form of one or more cross-strike elevation profiles or in the form of the slope-offset plot, a point plot of maximum scarp slope versus scarp offset. Working with either or both of these data representations for nine geologic structures, which range in age from 3 to 400 ka B.P. and in offset from 1 to 50 m, we apply analytical solutions for the vertical initial value scarp, the vertical continuous offset scarp, and the finite slope, initial value scarp. The model calculations are intrinsically ambiguous, yielding as the final answer only the product κt (in the case of the initial value problem) or the product κA−1 (in the case of the repeated faulting problem); here t is the age of a single scarp-forming event, 2A is the vertical slip rate, and κ is the “mass diffusivity.” A single profile across three sea cliffs along the Santa Cruz, California, coast is analyzed as three separate initial value problems. A reasonably constrained age for the sea cliff standing above the Highway 1 platform returns κ = 11 GKG (1 GKG = 1 m2/ka). With this κ, we can date the two older sea cliffs. In fact, we do the converse: age estimates for these two older sea cliffs based on a uniform rate of uplift both yield the same κ as for the lower sea cliff. We treat a single profile of the Raymond fault in Pasadena/San Marino in terms of the repeated faulting problem; for it the uplift rate of R. Crook and others yields κ = 16 GKG. The very substantial preexisting offset across the Raymond fault must have been buried/leveled some 230 ka B.P., when the modern topography began to form. Our analysis of the Lake Bonneville shoreline scarps reveals a dependence of κt on 2a, suggestive of nonlinear modification processes. This appearance is treated with the finite slope initial value scarp model to determine κ=1.1 GKG for the Lake Bonneville shoreline scarps. The suggestion of M. N. Machette that approximately 100,000-year-old, meter-high scarps are “unobservable” in weakly consolidated alluvial terranes of the Basin and Range and Rio Grande Rift Valley provinces can be formulated as κ ≳ 1 GKG. The coincidence between this inequality and the Lake Bonneville shoreline κ is striking, and it suggests that the value of κ = 1 GKG may be generally applicable, as a good first approximation, to the modification of alluvial terranes within the semiarid regions of the western United States. The Lake Bonneville shoreline κ is the basis for dating four sets of fault scarps in west-central Utah. The Drum Mountains fault scarps can be modeled in several different circumstances, but the most likely interpretation is that these fault scarps formed as the result of a single episode of normal faulting 3.6 to 5.7 ka B.P. The younger age is associated with quite low initial slope angles (25°). The other three sets of fault scarps show no evidence for finite initial value slopes. Fault scarps along the eastern base of the Fish Springs Range are very young, 3 ka B.P. We estimate the age of fault scarps along the western flank of the Oquirrh Mountains to be 32 ka B.P., which meets the weak geologic constraint that they be older than the Lake Bonneville shoreline. Fault scarps along the northeastern margin of the Sheeprock Mountains are even older, 53 ka B.P. An intriguing consequence of our single-event analysis of these scarps is that an 11.5-m offset occurred in a single earthquake.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB089iB07p05771","issn":"01480227","usgsCitation":"Hanks, T.C., Bucknam, R., Lajoie, K.R., and Wallace, R.E., 1984, Modification of wave-cut and faulting-controlled landforms: Journal of Geophysical Research Solid Earth, v. 89, no. B7, p. 5771-5790, https://doi.org/10.1029/JB089iB07p05771.","productDescription":"20 p.","startPage":"5771","endPage":"5790","numberOfPages":"20","costCenters":[],"links":[{"id":219865,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"89","issue":"B7","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a5cb4e4b0c8380cd6feb9","contributors":{"authors":[{"text":"Hanks, Thomas C.","contributorId":35763,"corporation":false,"usgs":true,"family":"Hanks","given":"Thomas","middleInitial":"C.","affiliations":[],"preferred":false,"id":366464,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bucknam, R.C.","contributorId":35744,"corporation":false,"usgs":true,"family":"Bucknam","given":"R.C.","affiliations":[],"preferred":false,"id":366463,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lajoie, K. R.","contributorId":6828,"corporation":false,"usgs":true,"family":"Lajoie","given":"K.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":366462,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Wallace, R. E.","contributorId":6823,"corporation":false,"usgs":true,"family":"Wallace","given":"R.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":366461,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70197498,"text":"70197498 - 1984 - Paleomagnetic constraints on the interpretation of early Cenozoic Pacific Northwest paleogeography","interactions":[],"lastModifiedDate":"2018-06-07T15:41:27","indexId":"70197498","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":5693,"text":"Pacific Section S.E.P.M.","active":true,"publicationSubtype":{"id":10}},"title":"Paleomagnetic constraints on the interpretation of early Cenozoic Pacific Northwest paleogeography","docAbstract":"Widespread Cenozoic clockwise tectonic rotation in the Pacific Northwest is an established fact; however, the geologic reconstructions based on these rotations are the subject of continuing debate. Three basic mechanisms have been proposed to explain the rotations: (1) simple shear rotation of marginal terranes caught in the dextral shear couple between oceanic plates and North America; (2) rotation during oblique microplate collision and accretion to the continental margin; and (3) rotation of continental margin areas during episodes of intracontinental extension. In areas where detailed structure and stratigraphy are available, distributed shear rotations are amplv demonstrated paleomagnetically. However, rotation due to asymmetric interarc extension must be significant, especially for the Oregon Coast Range, in light of recent estimates of large Tertiary extension across the northern Basin and Range. The relative importance of shear versus extension is difficult to determine, but shear could account for nearly onehalf of the observed rotations. Oblique microplate collision has not contributed significantly to the observed Cenozoic rotations because most of the rotation post-dates collision-related deformation in the Oregon and Washington. Coast Range. The resultant continental reconstructions suggest that about 300 km of extension has occurred at 42°N. latitude (southern Oregon border) since early Eocene time. This reconstruction suggests that Cretaceous sedimentary basins east of the Klamath Mountains have undergone significant Tertiary extension (about f<0%) , but little rotation. Upper Cretaceous sedimentary rocks in the Blue Mountains of Oregon near Mitchell are probably rotated at least 15° and perhaps as much as 60°, which allows considerable latitude in the restoration of that part of the basin.
","largerWorkTitle":"Geology of Upper Cretaceous Hornbrook Formation, Oregon and California","language":"English","publisher":"Society for the Sedimentary Geology","usgsCitation":"Wells, R., 1984, Paleomagnetic constraints on the interpretation of early Cenozoic Pacific Northwest paleogeography: Pacific Section S.E.P.M., v. 42, p. 231-237.","productDescription":"7 p.","startPage":"231","endPage":"237","costCenters":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"links":[{"id":354831,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":354830,"rank":1,"type":{"id":15,"text":"Index Page"},"url":"https://archives.datapages.com/data/pac_sepm/058/058001/pdfs/231.htm"}],"volume":"42","noUsgsAuthors":false,"publicationStatus":"PW","contributors":{"authors":[{"text":"Wells, Ray E. 0000-0002-7796-0160 rwells@usgs.gov","orcid":"https://orcid.org/0000-0002-7796-0160","contributorId":2692,"corporation":false,"usgs":true,"family":"Wells","given":"Ray E.","email":"rwells@usgs.gov","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":false,"id":737462,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70012833,"text":"70012833 - 1984 - Modeling crater topography and albedo from monoscopic Viking orbiter images: 1. Methodology","interactions":[],"lastModifiedDate":"2024-06-28T16:06:58.472398","indexId":"70012833","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Modeling crater topography and albedo from monoscopic Viking orbiter images: 1. Methodology","docAbstract":"A new photoclinometric technique for extraction of topographic data from single planetary images is presented that overcomes many previous limitations of photoclinometry. The procedure fully compensates for oblique viewing geometry prevalent in spacecraft images. Albedo variations have been one of the most serious obstacles in the application of photoclinometry to planetary surfaces. This problem is overcome in the topographic solution by simultaneously utilizing brightness data from a pair of profiles; both segments are assumed to have the same topographic and albedo variations along their lengths. Profile directions are chosen where the orientation of downslope or upslope is obvious, thus resolving a major ambiguity in photoclinometry. This requirement is particularly easy to satisfy for craters and not very difficult for many irregular features. An additional procedure is presented that eliminates even the requirement of topographic symmetry along the pair of profiles. If two profiles have the same relief but their shapes are very different, another method can be used in an iterative process to derive topographic profiles; however, this procedure does, require that the albedo not vary along the profiles. Test results indicate that both procedures have an accuracy and precision of approximately 2° for slopes of typical bowl-shaped craters, which translates to approximately 5% for depths.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB089iB11p09449","issn":"01480227","usgsCitation":"Davis, P.A., and Soderblom, L., 1984, Modeling crater topography and albedo from monoscopic Viking orbiter images: 1. Methodology: Journal of Geophysical Research Solid Earth, v. 89, no. B11, p. 9449-9457, https://doi.org/10.1029/JB089iB11p09449.","productDescription":"9 p.","startPage":"9449","endPage":"9457","numberOfPages":"9","costCenters":[],"links":[{"id":480212,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/jb089ib11p09449","text":"Publisher Index Page"},{"id":222041,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"89","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a5bebe4b0c8380cd6f8ce","contributors":{"authors":[{"text":"Davis, P. A.","contributorId":74021,"corporation":false,"usgs":true,"family":"Davis","given":"P.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":364636,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Soderblom, L.A. 0000-0002-0917-853X","orcid":"https://orcid.org/0000-0002-0917-853X","contributorId":6139,"corporation":false,"usgs":true,"family":"Soderblom","given":"L.A.","affiliations":[],"preferred":false,"id":364635,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013956,"text":"70013956 - 1984 - U-Th-Pb, Rb-Sr, and Ar-Ar mineral and whole-rock isotopic systematics in a metamorphosed granitic terrane, southeastern California","interactions":[],"lastModifiedDate":"2024-01-03T01:05:54.387059","indexId":"70013956","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"U-Th-Pb, Rb-Sr, and Ar-Ar mineral and whole-rock isotopic systematics in a metamorphosed granitic terrane, southeastern California","docAbstract":"Mesozoic structural domes are developed in an older Proterozoic crystalline basement of granitic to granodioritic foliate metaplutonic rocks in the Halloran Hills, southeastern California. Isotopic analyses of whole rocks and mineral separates from these rocks by U-Th-Pb, Rb-Sr, and Ar-Ar techniques yield a complex pattern of discordance that is the result of a fairly simple geologic history. Individual mineral isotopic systems have variably equilibrated with each other in response to Mesozoic regional metamorphism and locally to later heating during Mesozoic batholith emplacement.
Discordant U-Th-Pb zircon data indicate that the granitic core rocks are 1,710 Ma and that one dioritic phase may be slightly older. Rb-Sr whole-rock model dates scatter about 1,700 Ma Rb-Sr amphibole–whole-rock and U-Th-Pb amphibole dates are also Proterozoic. Potassium feldspars retain a 207Pb/206Pb signature of their Proterozoic age. Ar-Ar amphibole spectra from the flank of the main dome reveal disturbed dates of 1,450 Ma to 1,100 Ma, and the dates become younger toward the structurally deeper core of the dome.
All remaining isotopic determinations yield Mesozoic or younger dates for mineral–whole-rock systems. Rb-Sr whole-rock–apatite–feldspar–biotite analyses show nonequilibration of strontium isotopes, with resultant mineral pair dates from 4 foliate plutonic rocks ranging from 200 to 50 Ma. No single metamorphic age is indicated by the Rb-Sr data. Rb-Sr whole-rock–biotite dates are consistently younger than any other determinations and may be reduced by weathering or gain of nonradiogenic strontium from ground water.
U-Pb sphene and apatite analyses from rocks that yield 1,710-Ma zircon dates are nearly concordant at 140 Ma. An amphibole from the structurally deepest rocks of the main dome that yield 140- to 150-Ma U-Pb sphene dates has an Ar-Ar plateau date of 144 Ma. The U-Pb sphene and Ar-Ar amphibole analyses are believed to be the best age estimate for the end of the highest-temperature phase of regional metamorphism. Th-Pb sphene and apatite dates and Ar-Ar biotite dates cluster at 90 ± 5 Ma as a consequence of regional cooling during Late Cretaceous time following extensive Mesozoic plutonism in the region at 97 to 90 Ma.
We interpret the discordant mineral date patterns to have resulted from metamorphism of ∼1,700-Ma plutonic rocks during the Jurassic (≥ 140–50 Ma) and subsequent uplift and cooling to ∼200 °C at about 90 Ma. On the basis of this study, the isotope dating systems ranked in decreasing order of resistance to resetting are: U-Th-Pb zircon (concordia intercept) ≥ Rb-Sr whole rock ∼Rb-Sr amphibole ∼U-Th-Pb amphibole ∼Pb-Pb whole rock > Ar-Ar amphibole ≥ Rb-Sr sphene ≥ U-Pb sphene and apatite > Rb-Sr plagioclase-potassium feldspar-apatite > Th-Pb sphene and apatite ∼Ar-Ar biotite ∼U-Pb feldspars > Rb-Sr biotite.
The U.S. Geological Survey has been preparing and maintaining a library of standard reference water samples for inorganic constituents for 19 years. Recently, a pilot study was conducted to see if the reference-sample program could be expanded to include pesticides and other organic materials. Two samples containing organochlorine and organophosphorus insecticides, and chlorophenoxy acid herbicides were distributed to a number of laboratories in the United States. One of the samples also contained polychlorinated biphenyls. Interlaboratory data obtained from these round robin studies are presented with intralaboratory information on long-term stability.
","language":"English","publisher":"ASME","doi":"10.1520/JTE10706J","issn":"00903973","usgsCitation":"Friedman, L., Fishman, M.J., and Boyle, D., 1984, Pilot study for U.S. Geological Survey Standard Reference Water Samples for pesticides: Journal of Testing and Evaluation, v. 12, no. 2, p. 114-118, https://doi.org/10.1520/JTE10706J.","productDescription":"5 p.","startPage":"114","endPage":"118","numberOfPages":"5","costCenters":[],"links":[{"id":225986,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"12","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7b63e4b0c8380cd79406","contributors":{"authors":[{"text":"Friedman, L.C.","contributorId":57080,"corporation":false,"usgs":true,"family":"Friedman","given":"L.C.","email":"","affiliations":[],"preferred":false,"id":367119,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fishman, M. J.","contributorId":65069,"corporation":false,"usgs":true,"family":"Fishman","given":"M.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":367120,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Boyle, D.K.","contributorId":68892,"corporation":false,"usgs":true,"family":"Boyle","given":"D.K.","email":"","affiliations":[],"preferred":false,"id":367121,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70013893,"text":"70013893 - 1984 - Gas chromatographic analysis of volatiles in fluid and gas inclusions","interactions":[],"lastModifiedDate":"2017-05-03T16:02:39","indexId":"70013893","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2214,"text":"Journal of Chromatography A","active":true,"publicationSubtype":{"id":10}},"title":"Gas chromatographic analysis of volatiles in fluid and gas inclusions","docAbstract":"Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping.
These inclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels.
We present here some analyses of inclusions in a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography—mass spectrometry (GC—MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crusing surfaces, and is operated in a pure helium atmosphere at a controlled temperature.
Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC—MS. This combination of procedures has been shown to provide geochemically useful information on the process involved in the history of the samples analyzed.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0021-9673(01)89010-5","issn":"00219673","usgsCitation":"Andrawes, F., Holzer, G., Roedder, E., Gibson, E., and Oro, J., 1984, Gas chromatographic analysis of volatiles in fluid and gas inclusions: Journal of Chromatography A, v. 302, no. C, p. 181-193, https://doi.org/10.1016/S0021-9673(01)89010-5.","startPage":"181","endPage":"193","numberOfPages":"13","costCenters":[],"links":[{"id":225860,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"302","issue":"C","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a14c3e4b0c8380cd54b59","contributors":{"authors":[{"text":"Andrawes, F.","contributorId":102643,"corporation":false,"usgs":true,"family":"Andrawes","given":"F.","email":"","affiliations":[],"preferred":false,"id":367110,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Holzer, G.","contributorId":93206,"corporation":false,"usgs":true,"family":"Holzer","given":"G.","email":"","affiliations":[],"preferred":false,"id":367108,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Roedder, E.","contributorId":100986,"corporation":false,"usgs":true,"family":"Roedder","given":"E.","affiliations":[],"preferred":false,"id":367109,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Gibson, E.K. Jr.","contributorId":108256,"corporation":false,"usgs":true,"family":"Gibson","given":"E.K.","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":367111,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Oro, John","contributorId":21683,"corporation":false,"usgs":false,"family":"Oro","given":"John","email":"","affiliations":[{"id":33349,"text":"Department of Biophysical Science, University of Houston","active":true,"usgs":false}],"preferred":false,"id":367107,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70013346,"text":"70013346 - 1984 - Sm-Nd, K-Ar and petrologic study of some kimberlites from eastern United States and their implication for mantle evolution","interactions":[],"lastModifiedDate":"2012-03-12T17:18:40","indexId":"70013346","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1336,"text":"Contributions to Mineralogy and Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Sm-Nd, K-Ar and petrologic study of some kimberlites from eastern United States and their implication for mantle evolution","docAbstract":"We provide new data on Sm-Nd systematics, K-Ar dating and the major element chemistry of kimberlites from the eastern United States (mostly from central New York State) and their constituent mineral phases of olivine, clinopyroxene, garnet, phlogopite and perovskite. In addition, we report Nd-isotopes in a few kimberlites from South Africa, Lesotho and from the eastern part of China. The major element compositions of the New York dike rocks and of their constituent minerals including a xenolith of eclogite are comparable with those from the Kimberley area in South Africa. The K-Ar age of emplacement of the New York dikes is further established to be 143 Ma. We have analyzed the Nd-isotopic composition of the following kimberlites and related rocks: Nine kimberlite pipes from South Africa and Lesotho, two from southern India; one from the U.S.S.R., fifteen kimberlite pipes and related dike rocks from eastern and central U.S. and two pipes from the Shandong Province of eastern China. The age of emplacement of these kimberlites ranges from 1300 million years to 90 million years. The initial Nd-isotopic compositions of these kimberlitic rocks expressed as e{open}NdIwith respect to a chondritic bulk-earth growth-curve show a range between 0 and +4, with the majority of the kimberlites being in the range 0 to +2. This range is not matched by any other suite of mantle-derived igneous rocks. This result strengthens our earlier conclusion that kimberlitic liquids are derived from a relatively primeval and unique mantle reservoir with a nearly chondritic Sm/Nd ratio. ?? 1984 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Contributions to Mineralogy and Petrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF00373709","issn":"00107999","usgsCitation":"Basu, A.R., Rubury, E., Mehnert, H., and Tatsumoto, M., 1984, Sm-Nd, K-Ar and petrologic study of some kimberlites from eastern United States and their implication for mantle evolution: Contributions to Mineralogy and Petrology, v. 86, no. 1, p. 35-44, https://doi.org/10.1007/BF00373709.","startPage":"35","endPage":"44","numberOfPages":"10","costCenters":[],"links":[{"id":220031,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205000,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00373709"}],"volume":"86","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b917de4b08c986b31992b","contributors":{"authors":[{"text":"Basu, A. R.","contributorId":99697,"corporation":false,"usgs":true,"family":"Basu","given":"A.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":365861,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rubury, E.","contributorId":71692,"corporation":false,"usgs":true,"family":"Rubury","given":"E.","email":"","affiliations":[],"preferred":false,"id":365859,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mehnert, H.","contributorId":52326,"corporation":false,"usgs":true,"family":"Mehnert","given":"H.","affiliations":[],"preferred":false,"id":365858,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Tatsumoto, M.","contributorId":76798,"corporation":false,"usgs":true,"family":"Tatsumoto","given":"M.","email":"","affiliations":[],"preferred":false,"id":365860,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70013341,"text":"70013341 - 1984 - Deformation, geochemistry, and origin of massive sulfide deposits, Gossan lead district, Virginia","interactions":[],"lastModifiedDate":"2024-01-08T23:55:15.12474","indexId":"70013341","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1472,"text":"Economic Geology","active":true,"publicationSubtype":{"id":10}},"title":"Deformation, geochemistry, and origin of massive sulfide deposits, Gossan lead district, Virginia","docAbstract":"The Gossan Lead district is a 28-km-long, northeast-trending belt of discontinuous massive sulfide deposits in the Blue Ridge province of southwestern Virginia. The deposits, hosted by the Ashe Formation of late Proterozoic age, consist of strata-bound lenses and layers of massive pyrrhotite, minor chalcopyrite, sphalerite, and pyrite, and rare arsenopyrite and galena. Deposits were mined principally in the Iron Ridge and Betty Baker segments, respectively, at the southwestern and northeastern ends of the belt. Detailed mapping of the Gossan Howard, Huey, and Bumbarger pits in the Iron Ridge segment indicates that the deposits occur at one horizon and have been variously folded and brecciated after sulfide deposition. The Gossan Howard consists of a single, gently dipping lens of sulfide. The Huey deposit is complexly folded and locally contains tectonically thickened ore. The Bumbarger deposit is a lens as much as 40 m thick--the thickest known in the district. This deposit contains abundant coarse breccia fragments of wall rock around which the massive sulfide has flowed (during deformation and metamorphism), probably thickening the original deposit significantly. In the northeastern part of the district, drill holes intersect several sulfide layers that possibly are structurally repeated.The Ashe Formation in the district is a sequence of metasedimentary rocks and local conformable lenses of amphibolite and actinolite-chlorite schist. The metasedimentary rocks include metapelite, quartz-feldspar granofels (metagraywacke), and minor quartzite and carbonaceous schist, and are interpreted as marine turbidites. The amphibolites and other mafic rocks have chemical compositions similar to low Ti tholeiitic basalt, with a high Y/Nb (>10) and high average contents of Co (40 ppm), Cr (403 ppm), Ni (211 ppm), and V (247 ppm). Immobile trace element signatures (Ti-Y-Zr; Th-Hf-Ta; Ti-Cr) suggest a magmatic affinity with midocean ridge basalt (MORB); rare earth elements (REE) have low abundance levels (10X-15X chondrite), broadly flat patterns [(La/Yb) N = 0.7-1.1], and a slight depletion in the light elements similar to midocean ridge basalts. An amphibolite from a much higher stratigraphic level, south of the district, differs significantly from the mafic rocks closer to the sulfide zone in having the chemical signature of a transitional, slightly alkalic tholeiite with high TiO 2 (3.87 wt %), Fe 2 O 3 (16.4 wt %), and P 2 O 5 (0.56 wt %), low Y/Nb (3.3), and a highly fractionated rare earth element distribution [(La/Yb) N = 3.9] similar to continental basalt.Some silicate wall rocks of the deposits are mineralogically and chemically unusual, and differ substantially from the clastic metasediments of the Ashe Formation. Such rocks are composed mainly or wholly of plagioclase feldspar, biotite, chlorite, muscovite, or spessartine-rich garnet. The unusual lithologies form local strata-bound lenses in the footwall and/or hanging wall of the deposits, typically within 10 m of massive sulfide. The plagioclase rocks (3.4-7.6 wt % Na 2 O) consist largely of granoblastic albite-oligoclase (Ab (sub 78-90) ) with minor quartz and biotite; rare earth elements are highly fractionated [(La/Yb) N = 6.8-7.1] and their patterns resemble those of the quartz-feldspar granofels (metagraywacke) from the district.The biotite schists, locally monomineralic, have FeO/(FeO + MgO) = 0.5 and contain high phosphorus (1 wt % P 2 O 5 ) and fluorine (0.5 wt % F), present in fluorapatite. The chlorite schist is essentially all ripidolite; rare earth elements are highly fractionated, and have a large negative Eu anomaly. The spessartine-rich rocks (6.3-8.9 wt % MnO) are in places interlayered with the other unusual wall rocks and consist of abundant Mn-rich garnet (Sp 50 Al 23 Gr 19 Py 8 ) and minor quartz, plagioclase, pyrrhotite, and biotite. The distinctive mineralogy and chemistry of these rocks suggest that they represent metamorphosed alteration zones and/or intermixed chemical and clastic sediments.The sulfide deposits are interpreted as syngenetic in origin but modified in form by deformation which accompanied metamorphism. The great length of the mineralized district parallel to the regional strike and the flyschoid (turbidite) nature of the host rocks suggest that sedimentation and initial sulfide deposition took place in a deep, elongate marine basin or graben overlying a crustal rift zone. A rift underlying the sedimentary pile is consistent with the occurrence of mafic metavolcanic rocks of midocean ridge basalt affinity and could also have served as the feeder system for a line of hydrothermal vents on the sea floor that generated the sulfide deposits.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.79.7.1483","issn":"03610128","usgsCitation":"Gair, J., and Slack, J.F., 1984, Deformation, geochemistry, and origin of massive sulfide deposits, Gossan lead district, Virginia: Economic Geology, v. 79, no. 7, p. 1483-1520, https://doi.org/10.2113/gsecongeo.79.7.1483.","productDescription":"38 p.","startPage":"1483","endPage":"1520","numberOfPages":"38","costCenters":[],"links":[{"id":219973,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"79","issue":"7","noUsgsAuthors":false,"publicationDate":"1984-11-01","publicationStatus":"PW","scienceBaseUri":"5059fe4de4b0c8380cd4ec63","contributors":{"authors":[{"text":"Gair, J. E.","contributorId":50891,"corporation":false,"usgs":true,"family":"Gair","given":"J. E.","affiliations":[],"preferred":false,"id":365846,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Slack, J. F.","contributorId":75917,"corporation":false,"usgs":true,"family":"Slack","given":"J.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":365847,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013322,"text":"70013322 - 1984 - The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region","interactions":[],"lastModifiedDate":"2024-02-16T12:11:02.820689","indexId":"70013322","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region","docAbstract":"Radium has been measured in deep saline formation waters produced from a variety of U.S. Gulf Coast subsurface environments, including oil reservoirs, gas reservoirs and water-producing geopressured aquifers. A strong positive correlation has been found between formation-water salinity and Ra activity, resulting from the interaction of formation water with aquifer matrix. Ra isotopes enter the fluid phase after being produced by the decay of parent elements U and Th, which are located at sites on and within the solid matrix.
Processes that are belived to be primarily responsible for transferring Ra from matrix to formation water are chemical leaching and alpha-particle recoil. Factors controlling the observed salinity—Ra relationship may be one or a combination of the following factors: (a) ion exchange; (b) increased solubility of matrix silica surrounding Ra atoms, coupled with a salinity-controlled rate of reequilibration of silica between solution and quartz grains; and (c) the equilibration of Ra in solution with detrial barite within the aquifer.
No difference was found in the brine-Ra relation in water produced from oil or gas wells and water produced from wells penetrating only water-bearing aquifers, although the relation was more highly correlated for water-bearing aquifers than hydrocarbon-containing reservoirs.
Processes that are belived to be primarily responsible for transferring Ra from matrix to formation water are chemical leaching and alpha-particle recoil. Factors controlling the observed salinity—Ra relationship may be one or a combination of the following factors: (a) ion exchange; (b) increased solubility of matrix silica surrounding Ra atoms, coupled with a salinity-controlled rate of reequilibration of silica between solution and quartz grains; and (c) the equilibration of Ra in solution with detrial barite within the aquifer.
No difference was found in the brine-Ra relation in water produced from oil or gas wells and water produced from wells penetrating only water-bearing aquifers, although the relation was more highly correlated for water-bearing aquifers than hydrocarbon-containing reservoirs.
","language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(84)90186-4","issn":"01676695","usgsCitation":"Kraemer, T.F., and Reid, D., 1984, The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region: Chemical Geology, v. 46, no. 2, p. 153-174, https://doi.org/10.1016/0009-2541(84)90186-4.","productDescription":"22 p.","startPage":"153","endPage":"174","numberOfPages":"22","costCenters":[],"links":[{"id":220579,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"46","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bae31e4b08c986b323f4b","contributors":{"authors":[{"text":"Kraemer, T. F.","contributorId":63400,"corporation":false,"usgs":true,"family":"Kraemer","given":"T.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":365815,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reid, D.F.","contributorId":27188,"corporation":false,"usgs":true,"family":"Reid","given":"D.F.","email":"","affiliations":[],"preferred":false,"id":365814,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":1007755,"text":"1007755 - 1984 - Seed predation due to the yucca moth symbiosis","interactions":[],"lastModifiedDate":"2023-02-15T15:20:41.606075","indexId":"1007755","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":737,"text":"American Midland Naturalist","active":true,"publicationSubtype":{"id":10}},"title":"Seed predation due to the yucca moth symbiosis","docAbstract":"All species of Yucca (Agavaceae) require the pollinator services of a species of moth in the genus Tegeticula (Lepidoptera: Incurvariidae). These moths oviposit in the ovary of the plants and the larvae are entirely dependent upon Yucca seeds for food. The extent and distribution of larval seed predation was examined in nine Yucca species in the southwestern United States. The proportion of seeds destroyed by the yucca moth ranged from 3 % in Y. schidigera from coastal southern California to 45 % in one population of Y. angustissima from southern Utah. This sampling was done in 1979 at which time the Y. schidigera population averaged 0.6 larvae per fruit and the population of Y. angustissima averaged 9.3 larvae per fruit. A second sampling of these populations in 1982 averaged 0.5 for Y. schidigera and 5.6 for Y. angustissima. Several species showed significant differences between populations in the number of larvae per fruit. Contrary to expectation, based on the dogma that fruit production is dependent upon Tegeticula pollination (which is always followed by oviposition), a large number of fruits were found without larvae. The proportion varied greatly between populations but was as high as two thirds of all fruits in some populations. Observations suggested that these flowers had been pollinated by Tegeticula and the moths had oviposited in them but that the eggs failed to hatch.
","language":"English","publisher":"University of Notre Dame","doi":"10.2307/2425472","usgsCitation":"Keeley, J.E., Keeley, S.C., Swift, C.C., and Lee, J., 1984, Seed predation due to the yucca moth symbiosis: American Midland Naturalist, v. 112, p. 187-191, https://doi.org/10.2307/2425472.","productDescription":"5 p.","startPage":"187","endPage":"191","numberOfPages":"5","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":129829,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"112","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a0ae4b07f02db5fba24","contributors":{"authors":[{"text":"Keeley, Jon E. 0000-0002-4564-6521 jon_keeley@usgs.gov","orcid":"https://orcid.org/0000-0002-4564-6521","contributorId":1268,"corporation":false,"usgs":true,"family":"Keeley","given":"Jon","email":"jon_keeley@usgs.gov","middleInitial":"E.","affiliations":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"preferred":true,"id":315974,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Keeley, Sterling C.","contributorId":112968,"corporation":false,"usgs":true,"family":"Keeley","given":"Sterling","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":315972,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Swift, C. C.","contributorId":107639,"corporation":false,"usgs":true,"family":"Swift","given":"C.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":315975,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Lee, J.","contributorId":58596,"corporation":false,"usgs":true,"family":"Lee","given":"J.","affiliations":[],"preferred":false,"id":315973,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70012652,"text":"70012652 - 1984 - Evaporation from flowing channels","interactions":[],"lastModifiedDate":"2024-04-19T20:12:00.928766","indexId":"70012652","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2248,"text":"Journal of Energy Engineering - ASCE","active":true,"publicationSubtype":{"id":10}},"title":"Evaporation from flowing channels","docAbstract":"Stability‐dependent and Dalton‐type mass transfer formulas are determined from experimental evaporation data in ambient and heated channels and are shown to have similar performance in prediction of evaporation. The formulas developed are compared with those proposed by other investigators for lakes and flowing channels. The evaporation data were obtained from a heat‐budget analysis of two large outdoor channels, one of which received ambient‐temperature water from an adjacent reservoir while the other received an artificially‐heated discharge. Daily evaporation was calculated from bihourly values of water temperature and hourly values of meteorological variables for a 63‐day study period in the summer. The evaporation data were then used to derive mass transfer evaporation formulas for heated and ambient flowing channels.
","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)0733-9402(1984)110:1(1)","usgsCitation":"Fulford, J., and Sturm, T., 1984, Evaporation from flowing channels: Journal of Energy Engineering - ASCE, v. 110, no. 1, p. 1-9, https://doi.org/10.1061/(ASCE)0733-9402(1984)110:1(1).","productDescription":"9 p.","startPage":"1","endPage":"9","numberOfPages":"9","costCenters":[],"links":[{"id":222028,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"110","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0d10e4b0c8380cd52de0","contributors":{"authors":[{"text":"Fulford, J.M.","contributorId":27473,"corporation":false,"usgs":true,"family":"Fulford","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":364142,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sturm, T.W.","contributorId":79623,"corporation":false,"usgs":true,"family":"Sturm","given":"T.W.","email":"","affiliations":[],"preferred":false,"id":364143,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013910,"text":"70013910 - 1984 - Seismicity at Old Faithful Geyser: an isolated source of geothermal noise and possible analogue of volcanic seismicity","interactions":[],"lastModifiedDate":"2012-03-12T17:19:33","indexId":"70013910","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2499,"text":"Journal of Volcanology and Geothermal Research","active":true,"publicationSubtype":{"id":10}},"title":"Seismicity at Old Faithful Geyser: an isolated source of geothermal noise and possible analogue of volcanic seismicity","docAbstract":"Old Faithful Geyser in Yellowstone National Park, U.S.A., is a relatively isolated source of seismic noise and exhibits seismic behavior similar to that observed at many volcanoes, including \"bubblequakes\" that resemble B-type \"earthquakes\", harmonic tremor before and during eruptions, and periods of seismic quiet prior to eruptions. Although Old Faithful differs from volcanoes in that the conduit is continuously open, that rock-fracturing is not a process responsible for seismicity, and that the erupting fluid is inviscid H2O rather than viscous magma, there are also remarkable similarities in the problems of heat and mass recharge to the system, in the eruption dynamics, and in the seismicity. Water rises irregularly into the immediate reservoir of Old Faithful as recharge occurs, a fact that suggests that there are two enlarged storage regions: one between 18 and 22 m (the base of the immediate reservoir) and one between about 10 and 12 m depth. Transport of heat from hot water or steam entering at the base of the recharging water column into cooler overlying water occurs by migration of steam bubbles upward and their collapse in the cooler water, and by episodes of convective overturn. An eruption occurs when the temperature of the near-surface water exceeds the boiling point if the entire water column is sufficiently close to the boiling curve that the propagation of pressure-release waves (rarefactions) down the column can bring the liquid water onto the boiling curve. The process of conversion of the liquid water in the conduit at the onset of an eruption into a two-phase liquid-vapor mixture takes on the order of 30 s. The seismicity is directly related to the sequence of filling and heating during the recharge cycle, and to the fluid mechanics of the eruption. Short (0.2-0.3 s), monochromatic, high-frequency events (20-60 Hz) resembling unsustained harmonic tremor and, in some instances, B-type volcanic earthquakes, occur when exploding or imploding bubbles of steam cause transient vibrations of the fluid column. The frequency of the events is determined by the length of the water column and the speed of sound of the fluid in the conduit when these events occur; damping is controlled by the characteristic and hydraulic impedances, which depend on the above parameters, as well as on the recharge rate of the fluid. Two periods of reduced seismicity (of a few tens of seconds to nearly a minute in duration) occur during the recharge cycle, apparently when the water rises rapidly through the narrow regions of the conduit, causing a sudden pressure increase that temporarily suppresses steam bubble formation. A period of decreased seismicity also precedes preplay or an eruption; this appears to be the time when rising steam bubbles move into a zone of boiling that is acoustically decoupled from the wall of the conduit because of the acoustic impedance mismatch between boiling water (??c ??? 103 g cm-2 s-1) and rock (??c ??? 3 ?? 105 g cm2 s-1). Sustained harmonic tremor occurs during the first one to one-and-a-half minutes of an eruption of Old Faithful, but is not detectable in the succeeding minutes of the eruption. The eruption tremor is caused by hydraulic transients propagating within a sublayer of unvesiculated water that underlies the erupting two-phase liquid-vapor mixture. The resonant frequencies of the fluid column decrease to about 1 Hz when all of the water in the conduit has been converted to a water-steam mixture. Surges are observed in the flow at this frequency, but the resonance has not been detected seismically, possibly because the two-phase erupting fluid is seismically decoupled from the rock on which seismometers are placed. If Old Faithful is an analogue for volcanic seismicity, this study shows that because the frequency of tremor depends on the acoustic properties of the fluid and on conduit dimensions, both properties must be considered in analysis of tremor in volcanic regions. Because magma sound","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Volcanology and Geothermal Research","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"03770273","usgsCitation":"Kieffer, S.W., 1984, Seismicity at Old Faithful Geyser: an isolated source of geothermal noise and possible analogue of volcanic seismicity: Journal of Volcanology and Geothermal Research, v. 22, no. 1-2, p. 59-95.","startPage":"59","endPage":"95","numberOfPages":"37","costCenters":[],"links":[{"id":226119,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b8b93e4b08c986b31793c","contributors":{"authors":[{"text":"Kieffer, S. W.","contributorId":19186,"corporation":false,"usgs":true,"family":"Kieffer","given":"S.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":367147,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013752,"text":"70013752 - 1984 - Periodic floods from glacial Lake Missoula into the Sanpoil arm of glacial Lake Columbia, northeastern Washington","interactions":[],"lastModifiedDate":"2024-01-30T13:04:16.806817","indexId":"70013752","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Periodic floods from glacial Lake Missoula into the Sanpoil arm of glacial Lake Columbia, northeastern Washington","docAbstract":"At least 15 floods ascended the Sanpoil arm of glacial Lake Columbia during a single glaciation. Varves between 14 of the flood beds indicate one backflooding every 35 to 55 yr. This regularity suggests that the floods came from an ice-dammed lake that was self-dumping. Probably the self-dumping lake was glacial Lake Missoula, Montana, because the floods accord with inferred emptyings of that lake in frequency and number, apparently entered Lake Columbia from the east, and produced beds resembling backflood deposits of Lake Missoula floods in southern Washington.
For slowly moving freezing fronts in soil, the heat-transport equation may be approximated by the Laplacian of temperature. Consequently, potential theory may be assumed to apply and the temperature state can be approximated by an analytic function. The movement of freezing fronts may be approximated by a time-stepped solution of the phase-change problem, thus solving directly for heat flow across a freezing or thawing front. Moisture transport may approximated by using an exact solution of the moisture-transport equation assuming quasi-steady-state conditions, appropriate boundary conditions, and an exponential function relating unsaturated hydraulic conductivity (defined within the thawed zones) to pore water pressure (tension). This approach is used to develop a single model of ice segregation (frost-heave) in freezing soils. Applications to published and experimental one-dimension soil column freezing data show promising results.
","language":"English","publisher":"American Society of Mechanical Engineers","doi":"10.1115/1.3231116","issn":"01950738","usgsCitation":"Hromadka, T., and Guymon, G.L., 1984, A simple model of ice segregation using an analytic function to model heat and soil-water flow: Journal of Energy Resources Technology, Transactions of the ASME, v. 106, no. 4, p. 515-520, https://doi.org/10.1115/1.3231116.","productDescription":"6 p.","startPage":"515","endPage":"520","numberOfPages":"6","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":220586,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"106","issue":"4","noUsgsAuthors":false,"publicationDate":"1984-12-01","publicationStatus":"PW","scienceBaseUri":"505aaf55e4b0c8380cd87524","contributors":{"authors":[{"text":"Hromadka, T. V. II","contributorId":76464,"corporation":false,"usgs":true,"family":"Hromadka","given":"T. V.","suffix":"II","affiliations":[],"preferred":false,"id":365931,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Guymon, G. L.","contributorId":83941,"corporation":false,"usgs":true,"family":"Guymon","given":"G.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":365932,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013142,"text":"70013142 - 1984 - Chromite from the Blue Ridge province of North Carolina","interactions":[],"lastModifiedDate":"2023-02-06T17:24:41.688724","indexId":"70013142","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":732,"text":"American Journal of Science","active":true,"publicationSubtype":{"id":10}},"title":"Chromite from the Blue Ridge province of North Carolina","docAbstract":"Accessory chromite in dunite shows a variety of textures that indicate alteration. One group, type A, consists of four types of chromite: clean chromite; lattice chromite, in which the invading chlorite occurs along three directions in the (100) plane; optically zoned chromite; and poikiloblastic chromite. Most of type A chromites are surrounded by chromian clinochlore. The other group, type B, consists of euhedral to subhedral chromite grains which are included in olivine or pyroxene. The accessory chromites define a trend exhibited by chromite from other areas that have undergone metamorphism. Olivine-spinel geothermometry indicates equilibration temperatures near 700 degrees C, roughly consistent with mineral assemblages in the host gneisses. Thus, the Blue Ridge dunites are metamorphic rocks and not primary mantle peridotites.
","language":"English","publisher":"American Journal of Science","doi":"10.2475/ajs.284.4-5.507","usgsCitation":"Lipin, B.R., 1984, Chromite from the Blue Ridge province of North Carolina: American Journal of Science, v. 284, no. 4-5, p. 507-529, https://doi.org/10.2475/ajs.284.4-5.507.","productDescription":"23 p.","startPage":"507","endPage":"529","numberOfPages":"23","costCenters":[{"id":245,"text":"Eastern Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"links":[{"id":220465,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"North Carolina","otherGeospatial":"Blue Ridge province","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -82.33171420337254,\n 35.16172419965186\n ],\n [\n -80.3549144361715,\n 36.498699563512446\n ],\n [\n -81.74146209797348,\n 36.584654476715144\n ],\n [\n -82.80252728344371,\n 35.94894466653062\n ],\n [\n -84.26280999082724,\n 35.237774229031075\n ],\n [\n -84.35734406944783,\n 35.017268463518306\n ],\n [\n -83.03490976176494,\n 34.9746276516219\n ],\n [\n -82.33171420337254,\n 35.16172419965186\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"284","issue":"4-5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f5e2e4b0c8380cd4c489","contributors":{"authors":[{"text":"Lipin, Bruce R. blipin@usgs.gov","contributorId":5723,"corporation":false,"usgs":true,"family":"Lipin","given":"Bruce","email":"blipin@usgs.gov","middleInitial":"R.","affiliations":[],"preferred":true,"id":365391,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":1007761,"text":"1007761 - 1984 - Age-related mortality in a wintering population of dunlin","interactions":[],"lastModifiedDate":"2017-05-13T15:41:40","indexId":"1007761","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","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":"Age-related mortality in a wintering population of dunlin","docAbstract":"Despite considerable evidence that juvenile shorebirds experience significantly higher annual mortality rates than adults, identification and quantification of the sources of mortality have received little attention. We found that the proportion of juvenile Dunlins (Calidris alpina) in the kills of a Merlin (Falco columbarius) one winter at Bolinas Lagoon, California was greater than the proportion of juveniles in the lagoon's winter population. This is evidence that raptor predation may be one of the factors contributing to the age differences in annual mortality rates of shorebirds. We suggest that the greater vulnerability of juveniles to predation by the Merlin may be caused by age-related differences in Dunlin flocking behavior.
","language":"English","publisher":"American Ornithological Society","usgsCitation":"Kus, B., Ashman, P., Page, G., and Stenzel, L., 1984, Age-related mortality in a wintering population of dunlin: The Auk, v. 101, p. 69-73.","productDescription":"5 p.","startPage":"69","endPage":"73","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":129855,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":341260,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://www.jstor.org/stable/4086224 "}],"volume":"101","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4ae3e4b07f02db689232","contributors":{"authors":[{"text":"Kus, B.E.","contributorId":99492,"corporation":false,"usgs":true,"family":"Kus","given":"B.E.","email":"","affiliations":[],"preferred":false,"id":315986,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ashman, P.","contributorId":44867,"corporation":false,"usgs":true,"family":"Ashman","given":"P.","email":"","affiliations":[],"preferred":false,"id":315984,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Page, G.","contributorId":34463,"corporation":false,"usgs":true,"family":"Page","given":"G.","affiliations":[],"preferred":false,"id":315983,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Stenzel, L.","contributorId":91053,"corporation":false,"usgs":true,"family":"Stenzel","given":"L.","email":"","affiliations":[],"preferred":false,"id":315985,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70009978,"text":"70009978 - 1984 - The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region","interactions":[],"lastModifiedDate":"2013-01-21T08:39:44","indexId":"70009978","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region","docAbstract":"Radium has been measured in deep saline formation waters produced from a variety of U.S. Gulf Coast subsurface environments, including oil reservoirs, gas reservoirs and water-producing geopressured aquifers. A strong positive correlation has been found between formation-water salinity and Ra activity, resulting from the interaction of formation water with aquifer matrix. Ra isotopes enter the fluid phase after being produced by the decay of parent elements U and Th, which are located at sites on and within the solid matrix. Processes that are belived to be primarily responsible for transferring Ra from matrix to formation water are chemical leaching and alpha-particle recoil. Factors controlling the observed salinity-Ra relationship may be one or a combination of the following factors: (a) ion exchange; (b) increased solubility of matrix silica surrounding Ra atoms, coupled with a salinity-controlled rate of reequilibration of silica between solution and quartz grains; and (c) the equilibration of Ra in solution with detrial barite within the aquifer. No difference was found in the brine-Ra relation in water produced from oil or gas wells and water produced from wells penetrating only water-bearing aquifers, although the relation was more highly correlated for water-bearing aquifers than hydrocarbon-containing reservoirs. ?? 1984.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(84)90186-4","issn":"00092541","usgsCitation":"Kraemer, T.F., and Reid, D., 1984, The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region: Chemical Geology, v. 46, no. 2, p. 153-174, https://doi.org/10.1016/0009-2541(84)90186-4.","startPage":"153","endPage":"174","numberOfPages":"22","costCenters":[],"links":[{"id":266106,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(84)90186-4"},{"id":219659,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"46","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bae31e4b08c986b323f48","contributors":{"authors":[{"text":"Kraemer, T. F.","contributorId":63400,"corporation":false,"usgs":true,"family":"Kraemer","given":"T.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":357575,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reid, D.F.","contributorId":27188,"corporation":false,"usgs":true,"family":"Reid","given":"D.F.","email":"","affiliations":[],"preferred":false,"id":357574,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70013140,"text":"70013140 - 1984 - Petrochemistry, age and isotopic composition of alkali basalts from Ponape Island, Western Pacific","interactions":[],"lastModifiedDate":"2018-06-04T14:11:32","indexId":"70013140","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Petrochemistry, age and isotopic composition of alkali basalts from Ponape Island, Western Pacific","docAbstract":"Eleven analyzed lava samples from Ponape Island are alkali olivine basalt, basanite and basanitoid. Most lavas are aphyric or sparsely phyric (< 10% phenocrysts) and have phenocrysts of olivine (Fo77-80), clinopyroxene and titanomagnetite, and microphenocrysts of plagioclase (An53-68) in a fine-grained groundmass of olivine, clinopyroxene, plagioclase, opaques, potassic oligoclase, ?? nepheline and accessary phases. Oxygen isotope and Fe2O3 FeO data suggest that most samples are fresh, although H2O contents are high. Xenoliths of chromite-bearing harzburgites and dunites, both with cumulate textures occur in one locality. Major- and trace-element concentrations are similar to other oceanic volcanic islands. Most major elements and compatible trace elements vary systematically with respect to the Mg number [ 100Mg (Mg + Fe2+)]. In contrast, the incompatible trace elements do not correlate with the Mg number, but do covary with other incompatible elements. Simple closed-system shallow fractionation cannot be invoked to explain the observed chemical variation in the lavas. Derivation of the fractionated lavas (Mg number = 66-48) probably involved polybaric crystal fractionation from a high-Mg-number parental liquid. In addition, variable-source concentration of a trace-element-rich minor phase is postulated. However, the mantle was homogeneous with respect to the ratio of 87Sr 86Sr. New KAr age data are not consistent with the hypothesis that Ponape and the Caroline Ridge represent a simple \"hot spot\". ?? 1984.","language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(84)90138-4","issn":"00092541","usgsCitation":"Dixon, T., Batiza, R., Futa, K., and Martin, D., 1984, Petrochemistry, age and isotopic composition of alkali basalts from Ponape Island, Western Pacific: Chemical Geology, v. 43, no. 1-2, p. 1-28, https://doi.org/10.1016/0009-2541(84)90138-4.","productDescription":"28 p.","startPage":"1","endPage":"28","costCenters":[],"links":[{"id":220463,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266108,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(84)90138-4"}],"volume":"43","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a777ce4b0c8380cd784e1","contributors":{"authors":[{"text":"Dixon, T.H.","contributorId":14947,"corporation":false,"usgs":true,"family":"Dixon","given":"T.H.","email":"","affiliations":[],"preferred":false,"id":365383,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Batiza, Rodey","contributorId":95613,"corporation":false,"usgs":true,"family":"Batiza","given":"Rodey","email":"","affiliations":[],"preferred":false,"id":365386,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Futa, Kiyoto 0000-0001-8649-7510 kfuta@usgs.gov","orcid":"https://orcid.org/0000-0001-8649-7510","contributorId":619,"corporation":false,"usgs":true,"family":"Futa","given":"Kiyoto","email":"kfuta@usgs.gov","affiliations":[{"id":164,"text":"Central Energy Resources Science Center","active":true,"usgs":true}],"preferred":true,"id":365384,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Martin, D.","contributorId":75269,"corporation":false,"usgs":true,"family":"Martin","given":"D.","affiliations":[],"preferred":false,"id":365385,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70014007,"text":"70014007 - 1984 - Heating of a fully saturated Darcian half-space: Pressure generation, fluid expulsion, and phase change","interactions":[],"lastModifiedDate":"2024-02-14T14:54:34.999233","indexId":"70014007","displayToPublicDate":"1984-01-01T00:00:00","publicationYear":"1984","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2051,"text":"International Journal of Heat and Mass Transfer","active":true,"publicationSubtype":{"id":10}},"title":"Heating of a fully saturated Darcian half-space: Pressure generation, fluid expulsion, and phase change","docAbstract":"Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space.
","language":"English","publisher":"Elsevier","doi":"10.1016/0017-9310(84)90060-7","issn":"00179310","usgsCitation":"Delaney, P., 1984, Heating of a fully saturated Darcian half-space: Pressure generation, fluid expulsion, and phase change: International Journal of Heat and Mass Transfer, v. 27, no. 8, p. 1327-1335, https://doi.org/10.1016/0017-9310(84)90060-7.","productDescription":"9 p.","startPage":"1327","endPage":"1335","numberOfPages":"9","costCenters":[],"links":[{"id":225615,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"27","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a300ae4b0c8380cd5d310","contributors":{"authors":[{"text":"Delaney, P.","contributorId":107037,"corporation":false,"usgs":true,"family":"Delaney","given":"P.","email":"","affiliations":[],"preferred":false,"id":367357,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}