To investigate the possible relation between the fabric (microstructural arrangement of particles) of a fine-grained sedimentary deposit and the depositional and environmental processes of that deposit, the fabric of sediment samples from the sea floor of two different depositional settings, Shelikof Strait and the Alsek prodelta, Alaska, were studied by using scanning electron microscopy (SEM). Sediment of both areas is texturally similar, consisting of a muddy sand that grades to a mud with increasing water depth. Mineralogically, both areas are characterized by a clay-size fraction dominated by illite, chlorite, and rock flour. The dominant fabric of undisturbed sediment from both study areas consists of a sand- and coarse-silt-size agranular fraction surrounded by an open matrix of clay- and fine-silt-size platelets arranged in a combination of randomly oriented flocs and many single grain contacts. The similarity of the fabric of sediment from the two study areas suggests that the fabric is not controlled by the different depositional settings but rather by the dominant clay mineralogy and sediment texture. The most noticeable alteration of the original fabric of Shelikof Strait and Alsek prodelta sediment occurs as a result of high levels of consolidation and the shearing process.
Basalt pillow lava with glassy rims was dredged from 17 sites along the Gorda Ridge between latitudes 43°N and 40.8°N. All samples are low-K2O mid-ocean ridge tholeiitic basalt having a narrow compositional range with Mg numbers clustered around 60–62; more primitive and evolved compositions are present but rare. None of the more fractionated samples is as evolved as ferrobasalt from the Juan de Fuca Ridge. Incompatible trace element ratios are typical of normal mid-ocean ridge basalt but show considerable scatter. The 87Sr/86Sr ratios, ranging from 0.70233 to 0.70267, are near the low end of the range for normal mid-ocean ridge basalt. The phenocrysts present are abundant plagioclase, less abundant olivine ± spinel, and traces of sulfide. Clinopyroxene is absent in the glasses. The mineral chemistry is typical of ocean floor basalt. However, unusually anorthitic plagioclase in some highly plagioclasephyric samples, complex zoning in plagioclase and olivine, and other disequilibrium features indicate complex petrogenetic processes involving magma mixing. Glass inclusions in olivine and plagioclase indicate primitive trapped melts. The chemical diversity of Gorda Ridge lava appears to have been primarily caused by variable degrees of partial melting, but crystal fractionation and magma mixing were also important processes. Compositional variations along the strike of the ridge indicate that lava from the segment south of the offset at latitude 41.6°N was generated by the smallest percentage of partial melting of a source less depleted than that of the two northern segments. Lava from the central and northern segments was generated by variable percentages of partial melting of a uniformly depleted source. Lava from the northern segment shows the greatest diversity with a large range in percentage of melting and both relatively primitive and evolved compositions in spatially and temporally closely associated lava. The diversity of lava from the northern segment may result from thermal perturbations caused by proximity to the Blanco Fracture Zone. Gorda Ridge lava is more similar to that from the Mid-Atlantic Ridge at 22°–25°N than to that from other spreading centers in the Pacific Ocean. Magma chambers under the Gorda Ridge appear to be small, discontinuous in time and space and possibly at greater depth than those beneath other Pacific spreading centers.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB092iB10p10467","issn":"01480227","usgsCitation":"Davis, A.S., and Clague, D., 1987, Geochemistry, mineralogy, and petrogenesis of basalt from the Gorda Ridge: Journal of Geophysical Research Solid Earth, v. 92, no. B10, p. 10467-10483, https://doi.org/10.1029/JB092iB10p10467.","productDescription":"17 p.","startPage":"10467","endPage":"10483","costCenters":[],"links":[{"id":225395,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"92","issue":"B10","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a172ce4b0c8380cd553ec","contributors":{"authors":[{"text":"Davis, A. S.","contributorId":41424,"corporation":false,"usgs":true,"family":"Davis","given":"A.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":369030,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Clague, D.A.","contributorId":36129,"corporation":false,"usgs":true,"family":"Clague","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":369029,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70015204,"text":"70015204 - 1987 - Testing the consistency for mapping urban vegetation with high-altitude aerial photographs and landsat MSS data","interactions":[],"lastModifiedDate":"2017-01-18T14:37:57","indexId":"70015204","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3254,"text":"Remote Sensing of Environment","printIssn":"0034-4257","active":true,"publicationSubtype":{"id":10}},"title":"Testing the consistency for mapping urban vegetation with high-altitude aerial photographs and landsat MSS data","docAbstract":"Two methods of analysis were evaluated for mapping urban vegetation on high-altitude, color-infrared aerial photographs and Landsat MSS data of Syracuse, NY. The first method consisted of defining the spatial patterns (strata) of urban vegetation occurrence. The second method discriminated woody and herbaceous vegetation classes within defined strata. Emphasis was placed on evaluating the consistency of each method. Results indicate that consistent spatial patterns of urban vegetation strata were not achieved on either of the two data types tested due to the spatial complexity of the urban vegetation. However, for discriminating woody and herbaceous vegetation classes within defined strata, good consistency was noted among the interpreters of the high-altitude aerial photographs. The coarse spatial resolution of the Landsat MSS data resulted in low precision for identifying these two vegetation classes in this highly urbanized area. Where photointerpretation efforts are intended for mapping vegetation within numerous urban areas, the estimation of proportions of vegetation classes within defined strata should be a data analysis procedure more objective and consistently repeatable than is the delineation of vegetation patterns.
","language":"English","publisher":"Elsevier","doi":"10.1016/0034-4257(87)90050-2","issn":"00344257","usgsCitation":"Sadowski, F.G., Sturdevant, J.A., and Rowntree, R.A., 1987, Testing the consistency for mapping urban vegetation with high-altitude aerial photographs and landsat MSS data: Remote Sensing of Environment, v. 21, no. 2, p. 129-141, https://doi.org/10.1016/0034-4257(87)90050-2.","productDescription":"13 p.","startPage":"129","endPage":"141","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":223701,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"New York","county":"Syracuse","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -76.28082275390625,\n 42.9524020856897\n ],\n [\n -76.28082275390625,\n 43.13907396889933\n ],\n [\n -76.00616455078125,\n 43.13907396889933\n ],\n [\n -76.00616455078125,\n 42.9524020856897\n ],\n [\n -76.28082275390625,\n 42.9524020856897\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"21","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba5d3e4b08c986b320ce1","contributors":{"authors":[{"text":"Sadowski, Franklin G.","contributorId":91552,"corporation":false,"usgs":true,"family":"Sadowski","given":"Franklin","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":370320,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sturdevant, James A.","contributorId":67563,"corporation":false,"usgs":true,"family":"Sturdevant","given":"James","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":370319,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rowntree, Rowan A.","contributorId":37480,"corporation":false,"usgs":true,"family":"Rowntree","given":"Rowan","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":370318,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70015206,"text":"70015206 - 1987 - CHANGES IN GRADE, VOLUME AND CONTAINED GOLD DURING THE MINING LIFE-CYCLE OF GOLD PLACER DEPOSITS.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:56","indexId":"70015206","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1147,"text":"CIM Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"CHANGES IN GRADE, VOLUME AND CONTAINED GOLD DURING THE MINING LIFE-CYCLE OF GOLD PLACER DEPOSITS.","docAbstract":"Analysis of gold placer data throughout the world suggests that gold grades and volumes cannot be used to distinguish between most types of gold placers. Only the alluvial plain and fan placers are significantly different among the types of gold placers considered. Gold grades and volumes change when working placers go from small-volume methods to large-volume methods. The odds that a placer will be dominantly worked using small-volume methods at the surface are about 5:3. Once small-volume mining has occurred, the odds against subsequent large-volume mining are about 4:1. If a deposit is suitable for large-volume mining and the amount of gold produced from small-volume mining was reported, an estimate of the remaining gold (log//1//0kg) can be made using an equation.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"CIM Bulletin","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"03170926","usgsCitation":"Bliss, J.D., Orris, G., and Menzie, W., 1987, CHANGES IN GRADE, VOLUME AND CONTAINED GOLD DURING THE MINING LIFE-CYCLE OF GOLD PLACER DEPOSITS.: CIM Bulletin, v. 80, no. 903, p. 75-80.","startPage":"75","endPage":"80","numberOfPages":"6","costCenters":[],"links":[{"id":223703,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"80","issue":"903","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f2c9e4b0c8380cd4b388","contributors":{"authors":[{"text":"Bliss, J. D.","contributorId":25564,"corporation":false,"usgs":true,"family":"Bliss","given":"J.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":370323,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Orris, G. J.","contributorId":80252,"corporation":false,"usgs":true,"family":"Orris","given":"G. J.","affiliations":[],"preferred":false,"id":370325,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Menzie, W. D.","contributorId":52916,"corporation":false,"usgs":true,"family":"Menzie","given":"W. D.","affiliations":[],"preferred":false,"id":370324,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70015208,"text":"70015208 - 1987 - Diagenetic palaeotemperatures from aqueous fluid inclusions: re-equilibration of inclusions in carbonate cements by burial heating","interactions":[],"lastModifiedDate":"2024-10-07T16:05:32.518471","indexId":"70015208","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2748,"text":"Mineralogical Magazine","active":true,"publicationSubtype":{"id":10}},"title":"Diagenetic palaeotemperatures from aqueous fluid inclusions: re-equilibration of inclusions in carbonate cements by burial heating","docAbstract":"Diagenetic palaeotemperatures determined from aqueous fluid inclusions can be affected by re-equilibration during burial heating. Calculations based on the observed behaviour of inclusions in fluorite under external confining pressure allows prediction of the temperatures and depths of burial necessary to initiate re-equilibration of aqueous inclusions in the common size range 40 to 4 µm. Heating of 20° to 60°C over the initial trapping temperature may cause errors of 10° to 20°C in the homogenization temperature. This suggests re-equilibration may cause aqueous inclusions in carbonates to yield a poor record of their low-temperature history, but a useful record of the maximum temperature experienced by the host rock. Previous work suggests inclusions containing petroleum fluids will be less susceptible to re-equilibration.
","language":"English","publisher":"Cambridge University Press","doi":"10.1180/minmag.1987.051.362.02","usgsCitation":"Burruss, R., 1987, Diagenetic palaeotemperatures from aqueous fluid inclusions: re-equilibration of inclusions in carbonate cements by burial heating: Mineralogical Magazine, v. 51, no. 362, p. 477-481, https://doi.org/10.1180/minmag.1987.051.362.02.","productDescription":"5 p.","startPage":"477","endPage":"481","costCenters":[],"links":[{"id":223754,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"362","noUsgsAuthors":false,"publicationDate":"2018-07-05","publicationStatus":"PW","scienceBaseUri":"505a009ce4b0c8380cd4f807","contributors":{"authors":[{"text":"Burruss, R.C. 0000-0001-6827-804X","orcid":"https://orcid.org/0000-0001-6827-804X","contributorId":99574,"corporation":false,"usgs":true,"family":"Burruss","given":"R.C.","affiliations":[],"preferred":false,"id":370328,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70015209,"text":"70015209 - 1987 - PYROLYSIS/GAS CHROMATOGRAPHY/MASS SPECTROMETRY OF A SERIES OF BURIED WOODS AND COALIFIED LOGS THAT INCREASE IN RANK FROM PEAT TO SUBBITUMINOUS COAL.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:56","indexId":"70015209","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"PYROLYSIS/GAS CHROMATOGRAPHY/MASS SPECTROMETRY OF A SERIES OF BURIED WOODS AND COALIFIED LOGS THAT INCREASE IN RANK FROM PEAT TO SUBBITUMINOUS COAL.","docAbstract":"To better understand the coalification process, we have conducted numerous studies of the chemical structural composition of xylem tissue from gymosperm wood and related woods that has been coalified to varying degrees. The studies presented here, examine the chemical nature of buried and coalified xylem tissue at the molecular level. To achieve this, we employed pyrolysis/gas chromatography (py/gc) and pyrolysis/gas chromotography/mass spectrometry (py/gc/ms). Pyrolysis techniques have been used to examine peat, coal, coalified wood, and related substances. However, the technique has not been previously applied to a systematic and histologically-related series of coalified woods. It is particularly useful to compare the results from pyrolytic studies with the data obtained from solid-state **1**3C NMR.","largerWorkTitle":"ACS Division of Fuel Chemistry, Preprints","conferenceTitle":"American Chemical Society, Division of Fuel Chemistry. Volume 32, No. 2, Preprints of Papers.","conferenceLocation":"Denver, CO, USA","language":"English","publisher":"ACS","publisherLocation":"Washington, DC, USA","issn":"05693772","usgsCitation":"Hatcher, P., Lerch, H.E., Kotra, R.K., and Verheyen, V.T., 1987, PYROLYSIS/GAS CHROMATOGRAPHY/MASS SPECTROMETRY OF A SERIES OF BURIED WOODS AND COALIFIED LOGS THAT INCREASE IN RANK FROM PEAT TO SUBBITUMINOUS COAL., in ACS Division of Fuel Chemistry, Preprints, v. 32, no. 1, Denver, CO, USA, p. 85-93.","startPage":"85","endPage":"93","numberOfPages":"9","costCenters":[],"links":[{"id":223755,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7389e4b0c8380cd770d6","contributors":{"authors":[{"text":"Hatcher, Patrick G.","contributorId":17367,"corporation":false,"usgs":true,"family":"Hatcher","given":"Patrick G.","affiliations":[],"preferred":false,"id":370331,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lerch, Harry E. tlerch@usgs.gov","contributorId":600,"corporation":false,"usgs":true,"family":"Lerch","given":"Harry","email":"tlerch@usgs.gov","middleInitial":"E.","affiliations":[],"preferred":true,"id":370330,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kotra, Rama K. rkotra@usgs.gov","contributorId":237,"corporation":false,"usgs":true,"family":"Kotra","given":"Rama","email":"rkotra@usgs.gov","middleInitial":"K.","affiliations":[],"preferred":true,"id":370329,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Verheyen, Vincent T.","contributorId":70541,"corporation":false,"usgs":true,"family":"Verheyen","given":"Vincent","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":370332,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70014185,"text":"70014185 - 1987 - Solid-state 13C NMR studies of dissolved organic matter in pore waters from different depositional environments","interactions":[],"lastModifiedDate":"2025-03-14T22:17:29.036504","indexId":"70014185","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2958,"text":"Organic Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"Solid-state 13C NMR studies of dissolved organic matter in pore waters from different depositional environments","docAbstract":"Dissolved organic matter (DOM) in pore waters from sediments of a number of different depositional environments was isolated by ultrafiltration using membranes with a nominal molecular weight cutoff of 500. This > 500 molecular weight DOM represents 70–98% of the total DOM in these pore waters. We determined the gross chemical structure of this material using both solid-state 13C nuclear magnetic resonance spectroscopy and elemental analysis.
Our results show that the DOM in these pore waters appears to exist as two major types: one type dominated by carbohydrates and paraffinic structures and the second dominated by paraffinic and aromatic structures. We suggest that the dominance of one or the other structural type of DOM in the pore water depends on the relative oxidizing/reducing nature of the sediments as well as the source of the detrital organic matter. Under dominantly anaerobic conditions carbohydrates in the sediments are degraded by bacteria and accumulate in the pore water as DOM. However, little or no degradation of lignin occurs under these conditions. In contrast, sediments thought to be predominantly aerobic in character have DOM with diminished carbohydrate and enhanced aromatic character. The aromatic structures in the DOM from these sediments are thought to arise from the degradation of lignin. The large amounts of paraffinic structures in both types of DOM may be due to the degradation of unidentified paraffinic materials in algal or bacterial remains.
","language":"English","publisher":"Elsevier","doi":"10.1016/0146-6380(87)90029-5","usgsCitation":"Orem, W.H., and Hatcher, P.G., 1987, Solid-state 13C NMR studies of dissolved organic matter in pore waters from different depositional environments: Organic Geochemistry, v. 11, no. 2, p. 73-82, https://doi.org/10.1016/0146-6380(87)90029-5.","productDescription":"10 p.","startPage":"73","endPage":"82","costCenters":[],"links":[{"id":225558,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"11","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b923ce4b08c986b319d96","contributors":{"authors":[{"text":"Orem, William H. 0000-0003-4990-0539 borem@usgs.gov","orcid":"https://orcid.org/0000-0003-4990-0539","contributorId":577,"corporation":false,"usgs":true,"family":"Orem","given":"William","email":"borem@usgs.gov","middleInitial":"H.","affiliations":[{"id":241,"text":"Eastern Energy Resources Science Center","active":true,"usgs":true}],"preferred":true,"id":367806,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hatcher, Patrick G.","contributorId":93625,"corporation":false,"usgs":true,"family":"Hatcher","given":"Patrick","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":367807,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014644,"text":"70014644 - 1987 - The decarbonation and heat capacity of ZnCO3","interactions":[],"lastModifiedDate":"2024-04-03T15:32:38.552541","indexId":"70014644","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"displayTitle":"The decarbonation and heat capacity of ZnCO3","title":"The decarbonation and heat capacity of ZnCO3","docAbstract":"The decarbonation curve for ZnCO3 has been determined in the pressure range 3–20 kbar by using a combination of cold-seal vessels and piston-cylinder apparatus with NaCl assemblies. Heat capacities for both synthetic and natural ZnCO3 samples were measured by differential scanning calorimetry at temperatures ranging from 340 to 497 K. The results of these experiments indicate that the enthalpy of formation for smithsonite, ΔHf(1,298.15), is approximately −817. kJ/mol. which is about 4 kJ more negative than most tabulated values.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(87)90238-9","issn":"00167037","usgsCitation":"Haselton, H., and Goldsmith, J.R., 1987, The decarbonation and heat capacity of ZnCO3: Geochimica et Cosmochimica Acta, v. 51, no. 2, p. 261-265, https://doi.org/10.1016/0016-7037(87)90238-9.","productDescription":"5 p.","startPage":"261","endPage":"265","numberOfPages":"5","costCenters":[],"links":[{"id":225523,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baa83e4b08c986b322875","contributors":{"authors":[{"text":"Haselton, H.T.","contributorId":16437,"corporation":false,"usgs":true,"family":"Haselton","given":"H.T.","affiliations":[],"preferred":false,"id":368897,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Goldsmith, J. R.","contributorId":25981,"corporation":false,"usgs":true,"family":"Goldsmith","given":"J.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":368898,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014183,"text":"70014183 - 1987 - Ice erosion of a sea-floor knickpoint at the inner edge of the stamukhi zone, Beaufort Sea, Alaska","interactions":[],"lastModifiedDate":"2024-10-17T11:17:06.992235","indexId":"70014183","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2667,"text":"Marine Geology","active":true,"publicationSubtype":{"id":10}},"title":"Ice erosion of a sea-floor knickpoint at the inner edge of the stamukhi zone, Beaufort Sea, Alaska","docAbstract":"Intensive studies of 17 geographically and hydrologically diverse stream bed sediments provide information on the relation between grain size, surface area, and operationally defined geochemical phases (e.g. Mn oxides, amorphous Fe oxides) to trace element concentrations. Of the size fractions investigated (<2, <16, <63and<125 μm), the strongest correlation with trace elements occurs with the percent <63 μm or<125 μm fractions. As the proportion of these size fractions increases in the samples, so do the trace element concentrations. When surface area (as defined by nitrogen adsorption and the BET equations) increases, trace element levels also increase. Correlations between bulk sediment chemistry and surface area are as strong as those between sediment chemistry and the proportion of the <63or<125 μm fractions. Surface area appears to serve as a proxy for grain size. The strongest correlations between grain size and surface area are the same as for trace elements and grain size (with the <63or<125 μm fractions). Surface area also is affected by geochemical phase, as are the trace elements associated with sediments. Of the phases considered (carbonates, Mn oxides, reactive Fe, amorphous Fe, organic matter), amorphous Fe oxides appear to exert the greatest control over both surface area and trace element levels. The concentrations of various geochemical phases affect surface area, grain size, and trace element chemistry. However, the effect of phase is grain-size dependent. For material with mean grain sizes in the fine sand range and coarser (> 125 μm), each of the various phases contribute to overall sample surface area. For material having mean grain sizes in the very fine sand range and finer (<125 μm), the same phases act as surface-area inhibitors by cementing fine grains together to form aggregates. This increases the mean grain size of the sample and reduces the surface area. The presence of these aggregates may explain why the <63 μm or<125 μm size fractions are more important to sediment-trace element levels and surface area than other finer fractions.
The purpose of this study was to provide general information on the chemical, physical and structural properties of estuarine ice and show how it compares with sea ice found at higher latitudes in order to determine whether the ice in Great Bay can be used as an analog in the study of arctic sea ice.
Ice cores and water samples were collected during the 1983–1984 winter season at Adams Point in Great Bay, New Hampshire. Concentrations of chloride, nitrogen (as nitrate and nitrite), bromide, phosphate, sulfate and silicate were determined for samples chosen on the basis of identifiable stratigraphic layers (i.e. bubble size and shape, sediment layers, etc.).
Similarities between ice formation in Great Bay and those in the arctic regions include the nature of the freezing process and the ice types produced. In addition, the distribution and concentration of chemical constituents were found to be similar to those observed in arctic sea ice. Factors affecting the chemistry of the ice in Great Bay include rainfall during the freezing season, the presence of sediment layers in the ice cores, the nature of incorporation of brine into the crystal structure of the ice and the drainage of brine.
","largerWorkTitle":"Elsevier","language":"English","doi":"10.1016/0272-7714(87)90155-7","issn":"02727714","usgsCitation":"Meese, D., Gow, A.J., Mayewski, P., Ficklin, W., and Loder, T., 1987, The chemical, physical and structural properties of estuarine ice in Great Bay, New Hampshire: Estuarine, Coastal and Shelf Science, v. 24, no. 6, p. 833-840, https://doi.org/10.1016/0272-7714(87)90155-7.","productDescription":"8 p.","startPage":"833","endPage":"840","costCenters":[],"links":[{"id":223864,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"New Hampshire","otherGeospatial":"Adams Point, Great Bay","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -70.87049245209931,\n 43.097134275933456\n ],\n [\n -70.87024449127672,\n 43.097254349501355\n ],\n [\n -70.8701620853713,\n 43.097474981170905\n ],\n [\n -70.87040930308838,\n 43.0977758412572\n ],\n [\n -70.87082133261794,\n 43.09795635659984\n ],\n [\n -70.87343085296828,\n 43.09715406211606\n ],\n [\n -70.87395275703868,\n 43.09637181487281\n ],\n [\n -70.87356819614534,\n 43.096111063571726\n ],\n [\n -70.87323857252203,\n 43.096211352665165\n ],\n [\n -70.87235957619289,\n 43.096211352665165\n ],\n [\n -70.87145311122916,\n 43.09607094788808\n ],\n [\n -70.87054664626461,\n 43.09579013736814\n ],\n [\n -70.86966764993633,\n 43.09526862870126\n ],\n [\n -70.86991486765338,\n 43.095047989082104\n ],\n [\n -70.87021776574683,\n 43.09486773648993\n ],\n [\n -70.86975079894727,\n 43.09414563550743\n ],\n [\n -70.87005295393517,\n 43.094225869370234\n ],\n [\n -70.87041004619391,\n 43.09418575245164\n ],\n [\n -70.87060232664014,\n 43.09394505038949\n ],\n [\n -70.87139891706302,\n 43.09366423012162\n ],\n [\n -70.87167360341637,\n 43.09366423012162\n ],\n [\n -70.87183841522803,\n 43.093022350387116\n ],\n [\n -70.87249766247467,\n 43.09254093617136\n ],\n [\n -70.87230538202759,\n 43.091718511465245\n ],\n [\n -70.87156372887468,\n 43.09131732467449\n ],\n [\n -70.86958598713561,\n 43.09075565875216\n ],\n [\n -70.86933876941768,\n 43.09059518182801\n ],\n [\n -70.8671412785961,\n 43.09009368873055\n ],\n [\n -70.86667431179653,\n 43.08981285080284\n ],\n [\n -70.8655206291149,\n 43.0897326111579\n ],\n [\n -70.86477897596285,\n 43.08989309034209\n ],\n [\n -70.86458669551578,\n 43.09027422671892\n ],\n [\n -70.86406479144536,\n 43.09075565875216\n ],\n [\n -70.86403732280998,\n 43.09097631383591\n ],\n [\n -70.86502619367992,\n 43.091096670819326\n ],\n [\n -70.86538328593865,\n 43.09151791839838\n ],\n [\n -70.86524594276244,\n 43.091718511465245\n ],\n [\n -70.86461416415119,\n 43.09197928147037\n ],\n [\n -70.86403732280998,\n 43.09197928147037\n ],\n [\n -70.8638725109983,\n 43.09217987302617\n ],\n [\n -70.86453175824495,\n 43.09238046392562\n ],\n [\n -70.86433947779784,\n 43.09336334983351\n ],\n [\n -70.86411972871619,\n 43.09400522599404\n ],\n [\n -70.8646965700566,\n 43.09436627837772\n ],\n [\n -70.86508113095076,\n 43.09446657032865\n ],\n [\n -70.86565797229116,\n 43.09402528451574\n ],\n [\n -70.86598759591448,\n 43.09414563550743\n ],\n [\n -70.86639962544406,\n 43.094386336781184\n ],\n [\n -70.86681165497278,\n 43.0948276199924\n ],\n [\n -70.8671687472315,\n 43.09524884190944\n ],\n [\n -70.86738849631315,\n 43.09546948080495\n ],\n [\n -70.8680202749244,\n 43.09567006092976\n ],\n [\n -70.86834989854772,\n 43.09639214393695\n ],\n [\n -70.86867952217104,\n 43.09639214393695\n ],\n [\n -70.86892673988895,\n 43.0967130669855\n ],\n [\n -70.86917395760601,\n 43.09693370060535\n ],\n [\n -70.86983320485268,\n 43.09703398835151\n ],\n [\n -70.87005295393517,\n 43.09719444840414\n ],\n [\n -70.87049245209931,\n 43.097134275933456\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"24","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baa2fe4b08c986b322753","contributors":{"authors":[{"text":"Meese, D.A.","contributorId":84095,"corporation":false,"usgs":true,"family":"Meese","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":370350,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gow, A. J.","contributorId":45070,"corporation":false,"usgs":false,"family":"Gow","given":"A.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":370348,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mayewski, P.A.","contributorId":14891,"corporation":false,"usgs":true,"family":"Mayewski","given":"P.A.","email":"","affiliations":[],"preferred":false,"id":370347,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ficklin, W.","contributorId":11885,"corporation":false,"usgs":true,"family":"Ficklin","given":"W.","affiliations":[],"preferred":false,"id":370346,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Loder, T.C.","contributorId":62817,"corporation":false,"usgs":true,"family":"Loder","given":"T.C.","email":"","affiliations":[],"preferred":false,"id":370349,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70015218,"text":"70015218 - 1987 - Subsidence, crustal structure, and thermal evolution of Georges Bank basin","interactions":[],"lastModifiedDate":"2023-01-17T17:28:18.801904","indexId":"70015218","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":701,"text":"American Association of Petroleum Geologists Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Subsidence, crustal structure, and thermal evolution of Georges Bank basin","docAbstract":"A geophysical study of Georges Bank basin defines a deep crustal structure that is interpreted in terms of the basin's tectonic and thermal history. Gravity models along three basin cross sections delineate two zones of crustal thinning at the basement hinge zone and oceanic crustal margins. These two zones bound rift-stage crust (about 25 km thick) which underlies the central portion of the basin. Subsidence analysis of the basin, using data from multichannel seismic reflection lines and two COST wells, suggests a rifting and (uniform) extensional origin. Two-dimensional finite difference modeling of the basin defines a crustal structure that concurs with the gravity and subsidence studies. The resulting isotherms show no major changes in the thermal structure since the ate Jurassic. In some areas of the basin, temperatures sufficient for oil generation are determined from maturation studies of Jurassic sediments. Hydrocarbon generation is questionable, however, because of the probable lack of proper and sufficient kerogen in the Jurassic deposits.
","language":"English","publisher":"American Association of Petroleum Geologists","doi":"10.1306/94887893-1704-11D7-8645000102C1865D","usgsCitation":"Swift, B.A., Sawyer, D.S., Grow, J.A., and Klitgord, K.D., 1987, Subsidence, crustal structure, and thermal evolution of Georges Bank basin: American Association of Petroleum Geologists Bulletin, v. 71, no. 6, p. 702-718, https://doi.org/10.1306/94887893-1704-11D7-8645000102C1865D.","productDescription":"17 p.","startPage":"702","endPage":"718","numberOfPages":"17","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":223920,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Georges Bank","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -72,\n 41\n ],\n [\n -72,\n 39\n ],\n [\n -66,\n 39\n ],\n [\n -66,\n 41\n ],\n [\n -72,\n 41\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"71","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aafa1e4b0c8380cd876d1","contributors":{"authors":[{"text":"Swift, B. Ann","contributorId":92685,"corporation":false,"usgs":true,"family":"Swift","given":"B.","email":"","middleInitial":"Ann","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":false,"id":370354,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sawyer, D. S.","contributorId":43875,"corporation":false,"usgs":true,"family":"Sawyer","given":"D.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":370352,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Grow, J. A.","contributorId":27858,"corporation":false,"usgs":true,"family":"Grow","given":"J.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":370351,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Klitgord, Kim D.","contributorId":82307,"corporation":false,"usgs":true,"family":"Klitgord","given":"Kim","email":"","middleInitial":"D.","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":false,"id":370353,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70015220,"text":"70015220 - 1987 - DISCRIMINATION OF ALTERED BASALTIC ROCKS IN THE SOUTHWESTERN UNITED STATES BY ANALYSIS OF LANDSAT THEMATIC MAPPER DATA.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:55","indexId":"70015220","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3052,"text":"Photogrammetric Engineering and Remote Sensing","active":true,"publicationSubtype":{"id":10}},"title":"DISCRIMINATION OF ALTERED BASALTIC ROCKS IN THE SOUTHWESTERN UNITED STATES BY ANALYSIS OF LANDSAT THEMATIC MAPPER DATA.","docAbstract":"Landsat Thematic Mapper image data were analyzed to determine their ability to discriminate red cone basalts from gray flow basalts and sedimentary country rocks for three volcanic fields in the southwestern United States. Analyses of all of the possible three-band combinations of the six nonthermal bands indicate that the combination of bands 1, 4, and 5 best discriminates among these materials. The color-composite image of these three bands unambiguously discriminates 89 percent of the mapped red volcanic cones in the three volcanic fields. Mineralogic and chemical analyses of collected samples indicate that discrimination is facilitated by the presence of hematite as a major mineral phase in the red cone basalts (hematite is only a minor mineral phase in the gray flow basalts and red sedimentary rocks).","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Photogrammetric Engineering and Remote Sensing","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00991112","usgsCitation":"Davis, P.A., Berlin, G., and Chavez, P.S., 1987, DISCRIMINATION OF ALTERED BASALTIC ROCKS IN THE SOUTHWESTERN UNITED STATES BY ANALYSIS OF LANDSAT THEMATIC MAPPER DATA.: Photogrammetric Engineering and Remote Sensing, v. 53, no. 1, p. 45-55.","startPage":"45","endPage":"55","numberOfPages":"11","costCenters":[],"links":[{"id":223922,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"53","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fd4ae4b0c8380cd4e751","contributors":{"authors":[{"text":"Davis, Philip A. pdavis@usgs.gov","contributorId":692,"corporation":false,"usgs":true,"family":"Davis","given":"Philip","email":"pdavis@usgs.gov","middleInitial":"A.","affiliations":[],"preferred":true,"id":370356,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Berlin, Graydon L.","contributorId":56106,"corporation":false,"usgs":true,"family":"Berlin","given":"Graydon L.","affiliations":[],"preferred":false,"id":370357,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Chavez, Pat S.","contributorId":82308,"corporation":false,"usgs":true,"family":"Chavez","given":"Pat","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":370358,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014181,"text":"70014181 - 1987 - Volatilization, transport and sublimation of metallic and non-metallic elements in high temperature gases at Merapi Volcano, Indonesia","interactions":[],"lastModifiedDate":"2024-04-03T15:49:10.560562","indexId":"70014181","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Volatilization, transport and sublimation of metallic and non-metallic elements in high temperature gases at Merapi Volcano, Indonesia","docAbstract":"Condensates, silica tube sublimates and incrustations were sampled from 500–800°C fumaroles and lava samples were collected at Merapi Volcano, Indonesia in Jan.–Feb., 1984. With respect to the magma, Merapi gases are enriched by factors greater than 105 in Se, Re, Bi and Cd; 104–105 in Au, Br, In, Pb and W; 103–104 in Mo, Cl, Cs, S, Sn and Ag; 102–103 in As, Zn, F and Rb; and 1–102 in Cu, K, Na, Sb, Ni, Ga, V, Fe, Mn and Li. The fumaroles are transporting more than 106 grams/day (
With decreasing temperature (800-500°C) there were five sublimate zones found in silica tubes: 1) cristobalite and magnetite (first deposition of Si, Fe and Al); 2) K-Ca sulfate, acmite, halite, sylvite and pyrite (maximum deposition of Cl, Na, K, Si, S, Fe, Mo, Br, Al, Rb, Cs, Mn, W, P, Ca, Re, Ag, Au and Co); 3) aphthitalite (K-Na sulfate), sphalerite, galena and Cs-K. sulfate (maximum deposition of Zn, Bi, Cd, Se and In; higher deposition of Pb and Sn); 4) Pb-K chloride and Na-K-Fe sulfate (maximum deposition of Pb, Sn and Cu); and 5) Zn, Cu and K-Pb sulfates (maximum deposition of Pb, Sn, Ti, As and Sb).
The incrustations surrounding the fumaroles are also chemically zoned. Bi, Cd, Pb, W, Mo, Zn, Cu, K, Na, V, Fe and Mn are concentrated most in or very close to the vent as expected with cooling, atmospheric contamination and dispersion. The highly volatile elements Br, Cl, As and Sb are transported primarily away from high temperature vents. Ba, Si, P, Al, Ca and Cr are derived from wall rock reactions.
Incomplete degassing of shallow magma at 915°C is the origin of most of the elements in the Merapi volcanic gas, although it is partly contaminated by particles or wall rock reactions. The metals are transported predominantly as chloride species. As the gas cools in the fumarolic environment, it becomes saturated with sublimate phases that fractionate from the gas in the order of their equilibrium saturation temperatures. Devolatilization of a cooling batholith could transport enough acids and metals to a hydrothermal system to play a significant role in forming an ore deposit. However, sublimation from a high temperature, high velocity carrier gas is not efficient enough to form a large ore deposit. Re, Se, Cd and Bi could be used as supporting evidence for magmatic fluid transport in an ore deposit.
","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(87)90258-4","issn":"00167037","usgsCitation":"Symonds, R., Rose, W.I., Reed, M., Lichte, F., and Finnegan, D., 1987, Volatilization, transport and sublimation of metallic and non-metallic elements in high temperature gases at Merapi Volcano, Indonesia: Geochimica et Cosmochimica Acta, v. 51, no. 8, p. 2083-2101, https://doi.org/10.1016/0016-7037(87)90258-4.","productDescription":"19 p.","startPage":"2083","endPage":"2101","numberOfPages":"19","costCenters":[],"links":[{"id":225494,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc2d0e4b08c986b32ada6","contributors":{"authors":[{"text":"Symonds, R.B.","contributorId":31011,"corporation":false,"usgs":true,"family":"Symonds","given":"R.B.","email":"","affiliations":[],"preferred":false,"id":367793,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rose, William I. Jr.","contributorId":71556,"corporation":false,"usgs":true,"family":"Rose","given":"William","suffix":"Jr.","email":"","middleInitial":"I.","affiliations":[],"preferred":false,"id":367794,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Reed, M.H.","contributorId":91606,"corporation":false,"usgs":true,"family":"Reed","given":"M.H.","email":"","affiliations":[],"preferred":false,"id":367796,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Lichte, F.E.","contributorId":99108,"corporation":false,"usgs":true,"family":"Lichte","given":"F.E.","affiliations":[],"preferred":false,"id":367797,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Finnegan, David L.","contributorId":80410,"corporation":false,"usgs":true,"family":"Finnegan","given":"David L.","affiliations":[],"preferred":false,"id":367795,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70015224,"text":"70015224 - 1987 - Neutron activation determination of iridium, gold, platinum, and silver in geologic samples","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70015224","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2440,"text":"Journal of Radioanalytical and Nuclear Chemistry Articles","active":true,"publicationSubtype":{"id":10}},"title":"Neutron activation determination of iridium, gold, platinum, and silver in geologic samples","docAbstract":"Low-level methods for the determination of iridium and other noble metals have become increasingly important in recent years due to interest in locating abundance anomalies associated with the Cretaceous and Tertiary (K-T) boundary. Typical iridium anomalies are in the range of 1 to 100 ??g/kg (ppb). Thus methods with detection limits near 0.1 ??g/kg should be adequate to detect K-T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure developed in this study samples irradiated in the epithermal neutron facility of the U. S. Geological Survey TRIGA Reactor (Denver, Colorado) are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium perioxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1 and samples from K-T boundary sites in the Western Interior of North America. ?? 1987 Akade??miai Kiado??.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Radioanalytical and Nuclear Chemistry Articles","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers","doi":"10.1007/BF02036054","issn":"02365731","usgsCitation":"Millard, H.T., 1987, Neutron activation determination of iridium, gold, platinum, and silver in geologic samples: Journal of Radioanalytical and Nuclear Chemistry Articles, v. 113, no. 1, p. 125-132, https://doi.org/10.1007/BF02036054.","startPage":"125","endPage":"132","numberOfPages":"8","costCenters":[],"links":[{"id":205436,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF02036054"},{"id":224024,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"113","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6502e4b0c8380cd72acf","contributors":{"authors":[{"text":"Millard, Hugh T. Jr.","contributorId":67502,"corporation":false,"usgs":true,"family":"Millard","given":"Hugh","suffix":"Jr.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":370367,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70015225,"text":"70015225 - 1987 - PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70015225","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3336,"text":"Scanning Micros","active":true,"publicationSubtype":{"id":10}},"title":"PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.","docAbstract":"The PIXE (proton-induced X-ray emission) microprobe can be used for nondestructive, in-situ analyses of areas as small as those analyzed by the electron microprobe, and has a sensitivity of detection as much as two orders of magnitude better than the electron microprobe. Preliminary studies demonstrated that PIXE provides a capability for quantitative determination of elemental concentrations in individual coal maceral grains with a detection limit of 1-10 ppm for most elements analyzed. Encouraged by the earlier results, we carried out the analyses reported below to examine trace element variations laterally (over a km range) as well as vertically (cm to m) in the I and J coal beds in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in central Utah, and to compare the data with the data from two samples of eastern coals of Pennsylvanian age.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Scanning Micros","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"08917035","usgsCitation":"Minkin, J., Chao, E.C., Blank, H., and Dulong, F., 1987, PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.: Scanning Micros, v. 1, no. 2, p. 503-513.","startPage":"503","endPage":"513","numberOfPages":"11","costCenters":[],"links":[{"id":224025,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"1","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7382e4b0c8380cd770a7","contributors":{"authors":[{"text":"Minkin, J.A.","contributorId":38588,"corporation":false,"usgs":true,"family":"Minkin","given":"J.A.","affiliations":[],"preferred":false,"id":370368,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Chao, E. C. T.","contributorId":96713,"corporation":false,"usgs":true,"family":"Chao","given":"E.","email":"","middleInitial":"C. T.","affiliations":[],"preferred":false,"id":370371,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blank, Herma","contributorId":96013,"corporation":false,"usgs":true,"family":"Blank","given":"Herma","email":"","affiliations":[],"preferred":false,"id":370370,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Dulong, F.T.","contributorId":81490,"corporation":false,"usgs":true,"family":"Dulong","given":"F.T.","affiliations":[],"preferred":false,"id":370369,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70015226,"text":"70015226 - 1987 - Distribution and abundance of tidal marshes along the coast of Maine","interactions":[],"lastModifiedDate":"2020-09-08T15:05:38.543037","indexId":"70015226","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1583,"text":"Estuaries","active":true,"publicationSubtype":{"id":10}},"title":"Distribution and abundance of tidal marshes along the coast of Maine","docAbstract":"Planimetry studies of coastal geology maps prepared by the Maine Geological Survey show that there is more than an order of magnitude more tidal marsh area in the state of Maine than documented in previously published estimates. The highly convoluted coast of Maine, which is approximately 5,970 km long, contains almost 79 km2 of salt marsh, far more than any other New England state, New York, or the Bay of Fundy region. Reasonable estimates for the per-unit primary productivity of salt marshes lead to projections of total marsh productivity on the order of 1010 g dry weight yr−1 for the Maine coast and 1011 g dry weight yr−1 for the Gulf of Maine as a whole. Distribution of tidal marsh area is strongly controlled by coastal geomorphology, which varies considerably along the coast of Maine. The salt marsh area is concentrated in the southwestern coastal region of arcuate bays, where marshes have developed behind sandy beaches. A series of long islands and bedrock peninsulas in the south-central portion of the coast also provides sheltered areas where large marshes occur. Northeast of Penobscot Bay salt marshes become more numerous and smaller in average areal extent. A lack of protection from waves, along with limited sources of glacio-fluvial and glacio-marine sediments, restricts the occurrence of salt marshes in that region to the frignes of coves and tidal rivers.
","language":"English","publisher":"Springer","doi":"10.2307/1352176","usgsCitation":"Jacobson, H., Jacobson, G., and Kelley, J.T., 1987, Distribution and abundance of tidal marshes along the coast of Maine: Estuaries, v. 10, no. 2, p. 126-131, https://doi.org/10.2307/1352176.","productDescription":"6 p.","startPage":"126","endPage":"131","numberOfPages":"6","costCenters":[],"links":[{"id":224026,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Maine","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -70.3564453125,\n 42.8115217450979\n ],\n [\n -68.73046875,\n 43.77109381775651\n ],\n [\n -66.4892578125,\n 44.55916341529182\n ],\n [\n -67.32421875,\n 45.24395342262324\n ],\n [\n -69.3017578125,\n 45.213003555993964\n ],\n [\n -71.19140625,\n 44.02442151965934\n ],\n [\n -70.751953125,\n 43.068887774169625\n ],\n [\n -70.3564453125,\n 42.8115217450979\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"10","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0276e4b0c8380cd50063","contributors":{"authors":[{"text":"Jacobson, H.A.","contributorId":58028,"corporation":false,"usgs":true,"family":"Jacobson","given":"H.A.","email":"","affiliations":[],"preferred":false,"id":370373,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Jacobson, G.L.","contributorId":71321,"corporation":false,"usgs":true,"family":"Jacobson","given":"G.L.","email":"","affiliations":[],"preferred":false,"id":370374,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kelley, J. T.","contributorId":34197,"corporation":false,"usgs":true,"family":"Kelley","given":"J.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":370372,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70015227,"text":"70015227 - 1987 - The geochemistry of water near a surficial organic-rich uranium deposit, northeastern Washington State, U.S.A.","interactions":[],"lastModifiedDate":"2013-01-21T08:29:44","indexId":"70015227","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","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 geochemistry of water near a surficial organic-rich uranium deposit, northeastern Washington State, U.S.A.","docAbstract":"The chemistry of three stream, three spring and six near-surface waters in the vicinity of a Holocene organic-rich uranium deposit is described, with particular emphasis on the chemistry of U. Results characterize the solution behavior of uranium as U-bearing water interacts with relatively undecomposed, surficial organic matter. Of the measured major and trace chemical species, only U is consistently highly enriched (17-318 ppb) relative to reported values for regional waters, or to literature values for waters in largely granitic terrains. R-mode factor analysis of the chemical data suggests that most U is present in a soluble form, but that some U is also associated with fine suspended particulates of clay, organic matter, or hydrous oxides. Calculations that apply thermodynamic data to predict U speciation in solution indicate the relative importance of uranyl carbonate and uranyl phosphate complexes. Analysis of more finely filtered samples (0.05 ??m vs. 0.45 ??m), and direct radiographic observations using fission-track detectors suspended in the waters indicate the presence of some uraniferous particulate matter. Application of existing thermodynamic data for uranous- and uranyl-bearing minerals indicates that all waters are undersaturated with U minerals as long as ambient Eh ??? +0.1 v. If coexisting surface and near-surface waters are sufficiently oxidizing, initial fixation of U in the deposit should be by a mechanism of adsorption. Alternatively, more reducing conditions may prevail in deeper pore waters of the organic-rich host sediments, perhaps leading to direct precipitation or diagenetic formation of U4+ minerals. A 234U 238U alpha activity ratio of 1.08 ?? 0.02 in a spring issuing from a hillslope above the deposit suggests a relatively soluble source of U. In contrast, higher activity ratios of 234U 238U (??? 1.3) in waters in contact with the uraniferous valley-fill sediments suggest differences in the nature of interaction between groundwater and the local, U-rich source rocks. ?? 1987.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(87)90091-X","issn":"00092541","usgsCitation":"Zielinski, R.A., Otton, J.K., Wanty, R., and Pierson, C.T., 1987, The geochemistry of water near a surficial organic-rich uranium deposit, northeastern Washington State, U.S.A.: Chemical Geology, v. 62, no. 3-4, p. 263-289, https://doi.org/10.1016/0009-2541(87)90091-X.","startPage":"263","endPage":"289","numberOfPages":"27","costCenters":[],"links":[{"id":266099,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(87)90091-X"},{"id":224080,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"62","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bac50e4b08c986b3233fb","contributors":{"authors":[{"text":"Zielinski, R. A. 0000-0002-4047-5129","orcid":"https://orcid.org/0000-0002-4047-5129","contributorId":106930,"corporation":false,"usgs":true,"family":"Zielinski","given":"R.","email":"","middleInitial":"A.","affiliations":[{"id":164,"text":"Central Energy Resources Science Center","active":true,"usgs":true}],"preferred":false,"id":370378,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Otton, J. K.","contributorId":52589,"corporation":false,"usgs":true,"family":"Otton","given":"J.","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":370375,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wanty, R. B. 0000-0002-2063-6423","orcid":"https://orcid.org/0000-0002-2063-6423","contributorId":66704,"corporation":false,"usgs":true,"family":"Wanty","given":"R. B.","affiliations":[],"preferred":false,"id":370377,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Pierson, C. T.","contributorId":57055,"corporation":false,"usgs":true,"family":"Pierson","given":"C.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":370376,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70015228,"text":"70015228 - 1987 - LOUISIANA BARRIER ISLAND EROSION STUDY.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70015228","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"LOUISIANA BARRIER ISLAND EROSION STUDY.","docAbstract":"During 1986, the U. S. Geological Survey and the Louisiana Geological Survey began a five-year cooperative study focused on the processes which cause erosion of barrier islands. These processes must be understood in order to predict future erosion and to better manage our coastal resources. The study area includes the Louisiana barrier islands which serve to protect 41% of the nation's wetlands. These islands are eroding faster than any other barrier islands in the United States, in places greater than 20 m/yr. The study is divided into three parts: geological development of barrier islands, quantitative processes of barrier island erosion and applications of results. The study focuses on barrier islands in Louisiana although many of the results are applicable nationwide.","conferenceTitle":"Coastal Sediments '87, Proceedings of a Specialty Conference on Advances in Understanding of Coastal Sediment Processes.","conferenceLocation":"New Orleans, LA, USA","language":"English","publisher":"ASCE","publisherLocation":"New York, NY, USA","usgsCitation":"Sallenger, Penland, S., Williams, S.J., and Suter, J.R., 1987, LOUISIANA BARRIER ISLAND EROSION STUDY., Coastal Sediments '87, Proceedings of a Specialty Conference on Advances in Understanding of Coastal Sediment Processes., v. 2, New Orleans, LA, USA, p. 1503-1516.","startPage":"1503","endPage":"1516","numberOfPages":"14","costCenters":[],"links":[{"id":224081,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a40f1e4b0c8380cd6518b","contributors":{"authors":[{"text":"Sallenger, Jr.","contributorId":105768,"corporation":false,"usgs":true,"family":"Sallenger","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":370382,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Penland, Shea","contributorId":88401,"corporation":false,"usgs":false,"family":"Penland","given":"Shea","email":"","affiliations":[{"id":5115,"text":"Louisiana State University","active":true,"usgs":false}],"preferred":false,"id":370381,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Williams, S. Jeffress 0000-0002-1326-7420 jwilliams@usgs.gov","orcid":"https://orcid.org/0000-0002-1326-7420","contributorId":2063,"corporation":false,"usgs":true,"family":"Williams","given":"S.","email":"jwilliams@usgs.gov","middleInitial":"Jeffress","affiliations":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":370379,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Suter, John R.","contributorId":42362,"corporation":false,"usgs":false,"family":"Suter","given":"John","email":"","middleInitial":"R.","affiliations":[{"id":5115,"text":"Louisiana State University","active":true,"usgs":false}],"preferred":false,"id":370380,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70015229,"text":"70015229 - 1987 - NONHOMOGENEOUS TERMS IN THE UNSTEADY FLOW EQUATIONS: MODELING ASPECTS.","interactions":[],"lastModifiedDate":"2012-03-12T17:18:54","indexId":"70015229","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"NONHOMOGENEOUS TERMS IN THE UNSTEADY FLOW EQUATIONS: MODELING ASPECTS.","docAbstract":"A study is in progress to identify the relative significance, effects, and benefits attributable to the use of one-dimensional, unsteady, open-channel, flow-simulation models employing a variety of nonhomogeneous terms in their equation formulations. Nonhomogeneous terms being analyzed include those representing bed slope, frictional resistance, nonprismatic channel geometry, lateral flow, and (surface) wind stress. After an initial theoretical discussion, the results of a set of numerical experiments are presented that demonstrate cause-and-effect relationships and intercomparisons achieved by neglect or improper treatment of important nonhomogeneous terms. Preliminary results of this study are discussed and presented in this paper, both in the form of qualitative considerations and quantitative tabular findings. These results are expected to yield a definitive set of guidelines and suggestions useful to model engineers.","conferenceTitle":"Hydraulic Engineering, Proceedings of the 1987 National Conference.","conferenceLocation":"Williamsburg, VA, USA","language":"English","publisher":"ASCE","publisherLocation":"New York, NY, USA","isbn":"0872626105","usgsCitation":"Lai, C., Schaffranek, R.W., and Baltzer, R.A., 1987, NONHOMOGENEOUS TERMS IN THE UNSTEADY FLOW EQUATIONS: MODELING ASPECTS., Hydraulic Engineering, Proceedings of the 1987 National Conference., Williamsburg, VA, USA, p. 351-358.","startPage":"351","endPage":"358","numberOfPages":"8","costCenters":[],"links":[{"id":224082,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6169e4b0c8380cd71947","contributors":{"authors":[{"text":"Lai, Chintu","contributorId":16860,"corporation":false,"usgs":true,"family":"Lai","given":"Chintu","email":"","affiliations":[],"preferred":false,"id":370383,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schaffranek, Raymond W.","contributorId":86314,"corporation":false,"usgs":true,"family":"Schaffranek","given":"Raymond","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":370385,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Baltzer, Robert A.","contributorId":34269,"corporation":false,"usgs":true,"family":"Baltzer","given":"Robert","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":370384,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014179,"text":"70014179 - 1987 - A model of geomagnetic secular variation for 1980-1983","interactions":[],"lastModifiedDate":"2013-02-13T13:22:26","indexId":"70014179","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3071,"text":"Physics of the Earth and Planetary Interiors","active":true,"publicationSubtype":{"id":10}},"title":"A model of geomagnetic secular variation for 1980-1983","docAbstract":"We developed an updated model of the secular variation of the main geomagnetic field during 1980 through 1983 based on annual mean values for that interval from 148 worldwide magnetic observatories. The model consists of a series of 80 spherical harmonics, up to and including those of degree and order 8. We used it to form a proposal for the 1985 revision of the International Geomagnetic Reference Field (IGRF). Comparison of the new model, whose mean epoch is approximately 1982.0, with the Provisional Geomagnetic Reference Field for 1975-1980 (PGRF 1975), indicates that the moment of the centered-dipole part of the geomagnetic field is now decreasing faster than it was 5 years ago. The rate (in field units) indicated by PGRF 1975 was about -25 nT a-1, while for the new model it is -28 nT a-1. ?? 1987.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Physics of the Earth and Planetary Interiors","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/0031-9201(87)90155-5","issn":"00319201","usgsCitation":"Peddie, N., and Zunde, A., 1987, A model of geomagnetic secular variation for 1980-1983: Physics of the Earth and Planetary Interiors, v. 48, no. 3-4, p. 324-329, https://doi.org/10.1016/0031-9201(87)90155-5.","startPage":"324","endPage":"329","numberOfPages":"6","costCenters":[],"links":[{"id":267331,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0031-9201(87)90155-5"},{"id":225428,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"48","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e47fe4b0c8380cd46681","contributors":{"authors":[{"text":"Peddie, N.W.","contributorId":75911,"corporation":false,"usgs":true,"family":"Peddie","given":"N.W.","affiliations":[],"preferred":false,"id":367790,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Zunde, A.K.","contributorId":21946,"corporation":false,"usgs":true,"family":"Zunde","given":"A.K.","affiliations":[],"preferred":false,"id":367789,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014178,"text":"70014178 - 1987 - Generation of liquid water on Mars through the melting of a dusty snowpack","interactions":[],"lastModifiedDate":"2024-02-15T23:38:45.714936","indexId":"70014178","displayToPublicDate":"1987-01-01T00:00:00","publicationYear":"1987","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1963,"text":"Icarus","active":true,"publicationSubtype":{"id":10}},"title":"Generation of liquid water on Mars through the melting of a dusty snowpack","docAbstract":"The possibility that snowmelt could have provided liquid water for valley network formation early in the history of Mars is investigated using an optical-thermal model developed for dusty snowpacks at temperate latitudes. The heating of the postulated snow is assumed to be driven primarily by the absorption of solar radiation during clear sky conditions. Radiative heating rates are predicted as a function of depth and shown to be sensitive to the dust concentration and the size of the ice grains while the thermal conductivity is controlled by temperature, atmospheric pressure, and bulk density. Rates of metamorphism indicate that fresh fine-grained snow on Mars would evolve into moderately coarse snow during a single summer season. Results from global climate models are used to constrain the mean-annual surface temperatures for snow and the atmospheric exchange terms in the surface energy balance. Mean-annual temperatures within Martian snowpacks fail to reach the melting point for all atmospheric pressures below 1000 mbar despite a predicted temperature enhancement beneath the surface of the snowpacks. When seasonal and diurnal variations in the incident solar flux are included in the model, melting occurs at midday during the summer for a wide range of snow types and atmospheric pressures if the dust levels in the snow exceed 100 ppmw (parts per million by weight). The optimum dust concentration appears to be about 1000 ppmw. With this dust load, melting can occur in the upper few centimeters of a dense coarse-grained snow at atmospheric pressures as low as 7 mbar. Snowpack thickness and the thermal conductivity of the underlying substrate determine whether the generated snow-melt can penetrate to the snowpack base, survive basal ice formation, and subsequently become available for runoff. Under favorable conditions, liquid water becomes available for runoff at atmospheric pressures as low as 30 to 100 mbar if the substrate is composed of regolith, as is expected in the ancient cratered terrain of Mars.