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At least 109 records · Page 6Linked to original sources
USGS2009

Quality-Assurance Data for Routine Water Analyses by the U.S. Geological Survey Laboratory in Troy, New York - July 2005 through June 2007

The laboratory for analysis of low-ionic-strength water at the U.S. Geological Survey (USGS) Water Science Center in Troy, N.Y., analyzes samples collected by USGS projects throughout the Northeast. The laboratory's quality-assurance program is based on internal and interlaboratory quality-assurance samples and quality-control procedures that were developed to ensure proper sample collection, processing, and analysis. The quality-assurance and quality-control data were stored in the laboratory's Lab Master data-management system, which provides efficient review, compilation, and plotting of data. This report presents and discusses results of quality-assurance and quality control samples analyzed from July 2005 through June 2007. Results for the quality-control samples for 19 analytical procedures were evaluated for bias and precision. Control charts indicate that data for eight of the analytical procedures were occasionally biased for either high-concentration or low-concentration samples but were within control limits; these procedures were: total aluminum, calcium, magnesium, nitrate (colorimetric method), potassium, silicon, sodium, and sulfate. Eight of the analytical procedures were biased throughout the analysis period for the high-concentration sample, but were within control limits; these procedures were: total aluminum, calcium, dissolved organic carbon, chloride, nitrate (ion chromatograph), potassium, silicon, and sulfate. The magnesium and pH procedures were biased throughout the analysis period for the low-concentration sample, but were within control limits. The acid-neutralizing capacity, total monomeric aluminum, nitrite, and specific conductance procedures were biased for the high-concentration and low-concentration samples, but were within control limits. Results from the filter-blank and analytical-blank analyses indicated that the procedures for 16 of 17 analytes were within control limits, although the concentrations for blanks were occasionally outside the control limits. The data-quality objective was not met for dissolved organic carbon. Sampling and analysis precision are evaluated herein in terms of the coefficient of variation obtained for triplicate samples in the procedures for 18 of the 21 analytes. At least 93 percent of the samples met data-quality objectives for all analytes except acid-neutralizing capacity (85 percent of samples met objectives), total monomeric aluminum (83 percent of samples met objectives), total aluminum (85 percent of samples met objectives), and chloride (85 percent of samples met objectives). The ammonium and total dissolved nitrogen did not meet the data-quality objectives. Results of the USGS interlaboratory Standard Reference Sample (SRS) Project met the Troy Laboratory data-quality objectives for 87 percent of the samples analyzed. The P-sample (low-ionic-strength constituents) analysis had two outliers each in two studies. The T-sample (trace constituents) analysis and the N-sample (nutrient constituents) analysis had one outlier each in two studies. Results of Environment Canada's National Water Research Institute (NWRI) program indicated that at least 85 percent of the samples met data-quality objectives for 11 of the 14 analytes; the exceptions were acid-neutralizing capacity, total aluminum and ammonium. Data-quality objectives were not met in 41 percent of samples analyzed for acid-neutralizing capacity, 50 percent of samples analyzed for total aluminum, and 44 percent of samples analyzed for ammonium. Results from blind reference-sample analyses indicated that data-quality objectives were met by at least 86 percent of the samples analyzed for calcium, magnesium, pH, potassium, and sodium. Data-quality objectives were met by 76 percent of the samples analyzed for chloride, 80 percent of the samples analyzed for specific conductance, and 77 percent of the samples analyzed for sulfate.

Open-File Report↗
USGS2024

The petrology of dispersed organic matter in sedimentary rocks: Review and update

Organic petrology developed from coal petrology, and, in the 1960s, it began to be applied to the study of dispersed organic matter (DOM) in sedimentary rocks other than coal. Over the last few decades, the petrology of DOM has been used to characterize organic matter in sedimentary basins with an emphasis on fossil fuel resource exploration. Today, due to the global research shift on topics related to climate, organic petrology has expanded into new application areas, such as geothermal exploration, biological carbon storage (biochar), disposal, and management of radioactive waste. From the publication of the International Handbook of Coal Petrology (mid-20th century) to the present day, a large number of standards, books, and articles have been published as a result of the work of organic petrographers and petrologists around the world and efforts of the International Committee for Coal and Organic Petrology (ICCP) and The Society for Organic Petrology (TSOP) to promote the study of organic petrology. The current fundamentals and standards of organic petrology provide the international scientific community with well-informed guidance and recommendations to promote in-depth research. However, this information is currently widely scattered, leading to discrepancies in methodology and terminology. Therefore, this paper aims to present a comprehensive review of the main analytical standard test methods and techniques currently used in the petrology of DOM under reflected white light and UV and blue-light excitation, and to provide an efficient and well-defined reference guide. Furthermore, considering the important role of the ICCP in the development of organic petrology since the 1950s, a brief review of the ongoing activities of ICCP dealing with DOM is also presented.

International Journal of Coal Geology↗
USGS2006

Quality-Assurance Data for Routine Water Analyses by the U.S. Geological Survey Laboratory in Troy, New York-July 1997 through June 1999

The laboratory for analysis of low-ionic-strength water at the U.S. Geological Survey (USGS) Water Science Center in Troy, N.Y., analyzes samples collected by USGS projects throughout the Northeast. The laboratory's quality-assurance program is based on internal and interlaboratory quality-assurance samples and quality-control procedures that were developed to ensure proper sample collection, processing, and analysis. The quality-assurance/quality-control data for the time period addressed in this report were stored in the laboratory's SAS data-management system, which provides efficient review, compilation, and plotting of data. This report presents and discusses results of quality-assurance and quality- control samples analyzed from July 1997 through June 1999. Results for the quality-control samples for 18 analytical procedures were evaluated for bias and precision. Control charts indicate that data for eight of the analytical procedures were occasionally biased for either high-concentration and (or) low-concentration samples but were within control limits; these procedures were: acid-neutralizing capacity, total monomeric aluminum, total aluminum, ammonium, calcium, chloride, specific conductance, and sulfate. The data from the potassium and sodium analytical procedures are insufficient for evaluation. Results from the filter-blank and analytical-blank analyses indicate that the procedures for 11 of 13 analytes were within control limits, although the concentrations for blanks were occasionally outside the control limits. Blank analysis results for chloride showed that 22 percent of blanks did not meet data-quality objectives and results for dissolved organic carbon showed that 31 percent of the blanks did not meet data-quality objectives. Sampling and analysis precision are evaluated herein in terms of the coefficient of variation obtained for triplicate samples in the procedures for 14 of the 18 analytes. At least 90 percent of the samples met data-quality objectives for all analytes except total aluminum (70 percent of samples met objectives) and potassium (83 percent of samples met objectives). Results of the USGS interlaboratory Standard Reference Sample (SRS) Project indicated good data quality for most constituents over the time period. The P-sample (low-ionic-strength constituents) analysis had good ratings in two of these studies and a satisfactory rating in the third. The results of the T-sample (trace constituents) analysis indicated high data quality with good ratings in all three studies. The N-sample (nutrient constituents) studies had one each of excellent, good, and satisfactory ratings. Results of Environment Canada's National Water Research Institute (NWRI) program indicated that at least 80 percent of the samples met data-quality objectives for 9 of the 13 analytes; the exceptions were dissolved organic carbon, ammonium, chloride, and specific conductance. Data-quality objectives were not met for dissolved organic carbon in two NWRI studies, but all of the samples were within control limits for the last study. Data-quality objectives were not met in 41 percent of samples analyzed for ammonium, 25 percent of samples analyzed for chloride, and 30 percent of samples analyzed for specific conductance. Results from blind reference-sample analyses indicated that data-quality objectives were met by at least 84 percent of the samples analyzed for calcium, chloride, magnesium, pH, and potassium. Data-quality objectives were met by 73 percent of those analyzed for sulfate. The data-quality objective was not met for sodium. The data are insufficient for evaluation of the specific conductance results.

Open-File Report↗
USGS2016

Application of organic petrography in North American shale petroleum systems: A review

Organic petrography via incident light microscopy has broad application to shale petroleum systems, including delineation of thermal maturity windows and determination of organo-facies. Incident light microscopy allows practitioners the ability to identify various types of organic components and demonstrates that solid bitumen is the dominant organic matter occurring in shale plays of peak oil and gas window thermal maturity, whereas oil-prone Type I/II kerogens have converted to hydrocarbons and are not present. High magnification SEM observation of an interconnected organic porosity occurring in the solid bitumen of thermally mature shale reservoirs has enabled major advances in our understanding of hydrocarbon migration and storage in shale, but suffers from inability to confirm the type of organic matter present. Herein we review organic petrography applications in the North American shale plays through discussion of incident light photographic examples. In the first part of the manuscript we provide basic practical information on the measurement of organic reflectance and outline fluorescence microscopy and other petrographic approaches to the determination of thermal maturity. In the second half of the paper we discuss applications of organic petrography and SEM in all of the major shale petroleum systems in North America including tight oil plays such as the Bakken, Eagle Ford and Niobrara, and shale gas and condensate plays including the Barnett, Duvernay, Haynesville-Bossier, Marcellus, Utica, and Woodford, among others. Our review suggests systematic research employing correlative high resolution imaging techniques and in situ geochemical probing is needed to better document hydrocarbon storage, migration and wettability properties of solid bitumen at the pressure and temperature conditions of shale reservoirs.

International Journal of Coal Geology↗
USGS2011

Geomagnetic Workshop

A workshop on geomagnetism, sponsored by the Geologic Division of the U.S. Geological Survey, was held in the Denver West Office Complex in Golden, Colorado, April 13–15, 1982. There were 90 registered participants from government agencies, academic institutions, and industry. This effort stemmed from the realization that geomagnetism, once a small but coherent discipline, has now expanded into numerous areas of the geosciences, yet those doing research in these specialties seldom make contact outside their area of immediate interest. The impetus for this event came from the members of a committee formed to review the geomagnetic activities within the U.S. Geological Survey. They observed that the level of communication between the various elements of this now diverse discipline was inadequate, not only within their organization but also between federal agencies, academia, and the private sector. While the desire was to cover as much of geomagnetism as possible, it was necessary for a workshop of reasonable size and length to exclude some important areas of the subject: magnetic reversal chronology, studies of the externally produced variations, and most aspects of internal induction. The plan was to give emphasis to some of the newer areas: those which have recently seen a high level of activity and those with increasing activity abroad compared to that in the United States. The purpose was to evaluate the status and problems in selected areas with an eye to those whose emphasis might produce fruitful results in the next decade.

Eos, Transactions, American Geophysical Union↗
USGS2007

Regional Studies of the Potwar Plateau Area, Northern Pakistan

The papers in this volume are products of a cooperative program between the Geological Survey of Pakistan (GSP) and the U.S. Geological Survey (USGS), sponsored by the Government of Pakistan and the U.S. Agency for International Development. The focus of the program, the Coal Resources Exploration and Assessment Program (COALREAP), was to explore and assess Pakistan?s indigenous coal resources. As part of COALREAP, GSP and USGS geologists conducted regional geologic studies from 1988 to 1991 of the coal-bearing areas in the Potwar region of northern Pakistan. A reference section was selected from which to obtain faunal and floral analyses. The composite sections at Nammal Pass and Nammal Dam served as the basis for this regional reference. Although this Bulletin 2078 is being released in 2007, the writing and technical reviews were completed in 1993, and the chapters reflect the work done until that time. During the long production process for the Bulletin, which ultimately resulted in the oversize plates being digitized, the scientific content of the chapters was not changed, and most reports published since 1993 were not cited. A change in the age of the Patala Formation is discussed below [in the full preface], but the age discussions and illustrations in the chapters were not updated.

Bulletin↗
USGS2019

The state of the world’s mangrove forests: Past, present, and future

Intertidal mangrove forests are a dynamic ecosystem experiencing rapid changes in extent and habitat quality over geological history, today and into the future. Climate and sea level have drastically altered mangrove distribution since their appearance in the geological record ∼75 million years ago (Mya), through to the Holocene. In contrast, contemporary mangrove dynamics are driven primarily by anthropogenic threats, including pollution, overextraction, and conversion to aquaculture and agriculture. Deforestation rates have declined in the past decade, but the future of mangroves is uncertain; new deforestation frontiers are opening, particularly in Southeast Asia and West Africa, despite international conservation policies and ambitious global targets for rehabilitation. In addition, geological and climatic processes such as sea-level rise that were important over geological history will continue to influence global mangrove distribution in the future. Recommendations are given to reframe mangrove conservation, with a view to improving the state of mangroves in the future.

Annual Review of Environment and Resources↗
USGS1968

Experimental evidence that fluid inclusions do not leak

The possibility of leakage of fluids into or out of fluid inclusions subjected to large pressure gradients has always been considered a serious problem in the interpretation of inclusion data. As previous experimental evidence on leakage was contradictory, new experiments were performed. Inclusion vapor bubble diameters in twelve quartz crystals (≤ 3 mm; 8 localities), not sawn, ground or polished, were measured. The samples were run at Pa-.o,-4,000 bars, at T u 100°-410° C, for ≤ 17 days total, and remeasured after each run. Similar experiments at ≤ 155° C were made on sphalerite and calcite. Most inclusions in most samples (even those only 5am under the surface in quartz) showed no change in bubble diameter, hence no leakage. A few exceptions, mainly among inclusions homogenizing at T « Tru, had P internal » P internal , hence they ruptured and lost liquid during the 410° C run. From this work and a review of the literature, we conclude that most inclusions have not suffered major leakage. Some previous experiments indicating leakage may be explained by microfractures introduced during sample preparation. The present work does not , however, preclude the possibility of diffusion of small but chemically significant amounts of substances such as hydrogen in or out of inclusions .

Economic Geology↗
USGS2013

Conservation and Ecology of Marine Forage Fishes--Proceedings of a Research Symposium, September 2012

Locally and globally, there is growing recognition of the critical roles that herring, smelt, sand lance, eulachon, and other forage fishes play in marine ecosystems. Scientific and resource management entities throughout the Salish Sea, agree that extensive information gaps exist, both in basic biological knowledge and parameters critical to fishery management. Communication and collaboration among researchers also is inadequate. Building on the interest and enthusiasm generated by recent forage fish workshops and symposia around the region, the 2012 Research Symposium on the Conservation and Ecology of Marine Forage Fishes was designed to elucidate practical recommendations for science and policy needs and actions, and spur further collaboration in support for the precautionary management of forage fish. This dynamic and productive event was a joint venture of the Northwest Straits Commission Forage Fish Program, U.S. Geological Survey (USGS), Washington Department of Fish and Wildlife (WDFW), and The Puget Sound Partnership. The symposium was held on September 12–14, 2012, at the University of Washington, Friday Harbor Laboratories campus. Sixty scientists, graduate students, and fisheries policy experts convened; showcasing ongoing research, conservation, and management efforts targeting forage fish from regional and national perspectives. The primary objectives of this event were to: (1) review current research and management related to marine forage fish species; and (2) identify priority science and policy needs and actions for Washington, British Columbia, and the entire West Coast. Given the diversity of knowledge, interests, and disciplines surrounding forage fish on both sides of the international border, the organizing committee made a concerted effort to contact many additional experts who, although unable to attend, provided valuable insights and ideas to the symposium structure and discussions. The value of the symposium format was highlighted in the closing remarks delivered by Joseph Gaydos, SeaDoc Society and Chair of the Puget Sound Science Panel. Dr. Gaydos’ presentation referenced the 2011 paper by Murray Rudd in the journal Conservation Biology , “How research-prioritization exercises affect conservation policy.” The paper points out that policy makers and funding agencies are more likely to gain a full understanding of issues when they are presented with research findings from an aligned research program. That is, compared to unaligned research strategies, where work is not based on identified research priorities.

Open-File Report↗
USGS2009

Web GIS in practice VII: stereoscopic 3-D solutions for online maps and virtual globes

Because our pupils are about 6.5 cm apart, each eye views a scene from a different angle and sends a unique image to the visual cortex, which then merges the images from both eyes into a single picture. The slight difference between the right and left images allows the brain to properly perceive the 'third dimension' or depth in a scene (stereopsis). However, when a person views a conventional 2-D (two-dimensional) image representation of a 3-D (three-dimensional) scene on a conventional computer screen, each eye receives essentially the same information. Depth in such cases can only be approximately inferred from visual clues in the image, such as perspective, as only one image is offered to both eyes. The goal of stereoscopic 3-D displays is to project a slightly different image into each eye to achieve a much truer and realistic perception of depth, of different scene planes, and of object relief. This paper presents a brief review of a number of stereoscopic 3-D hardware and software solutions for creating and displaying online maps and virtual globes (such as Google Earth) in "true 3D", with costs ranging from almost free to multi-thousand pounds sterling. A practical account is also given of the experience of the USGS BRD UMESC (United States Geological Survey's Biological Resources Division, Upper Midwest Environmental Sciences Center) in setting up a low-cost, full-colour stereoscopic 3-D system.

International Journal of Health Geographics↗
USGS2026

USGS 2025 critical minerals review

The United States Geological Survey (USGS) provides scientific information for the Department of Interior and the nation, consistent with its original mission expressed in the Organic Act of 1879 (43 U.S.C. 31): “the classification of the public lands and examination of the geological structure, mineral resources, and products within and outside the national domain.” Legislation such as the Energy Act of 2020 and the 2022 Infrastructure Investment and Jobs Act (43 USC 31l) and recent executive actions (Executive Orders 14154 , 14153, 14241 Secretary’s Orders 3417, 3418, 3422, 3436) underscore the importance of mineral resources and focus USGS activities on mapping and assessing mineral resources, with a particular focus on those presently identified as critical, both in ground and above ground in mine wastes. This article reviews selected activities and accomplishments by the USGS Mineral Resources Program related to critical minerals in 2025. Highlights include a new List of Critical Minerals, a first-ever national mine waste inventory, international minerals partnerships, mineral resource assessment advancements, and national data collection activities and outcomes of the Earth Mapping Resources Initiative (Earth MRI). The selected contributions are not comprehensive but are intended to demonstrate USGS leadership in critical mineral mapping and assessment, the importance of domestic and global partnerships, and the breadth of research activities that are responsive to national needs and priorities.

Mining Engineering↗
USGS2000

Acoustic Doppler Current Profiler Data Processing System manual [ADCP]

This open-file report describes the data processing software currently in use by the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), to process time series of acoustic Doppler current data obtained by Teledyne RD Instruments Workhorse model ADCPs. The Sediment Transport Instrumentation Group (STG) at the WHCMSC has a long-standing commitment to providing scientists high quality oceanographic data published in a timely manner. To meet this commitment, STG has created this software to aid personnel in processing and reviewing data as well as evaluating hardware for signs of instrument malfunction. The output data format for the data is network Common Data Form (netCDF), which meets USGS publication standards. Typically, ADCP data are recorded in beam coordinates. This conforms to the USGS philosophy to post-process rather than internally process data. By preserving the original data quality indicators as well as the initial data set, data can be evaluated and reprocessed for different types of analyses. Beam coordinate data are desirable for internal and surface wave experiments, for example. All the code in this software package is intended to run using the MATLAB program available from The Mathworks, Inc. As such, it is platform independent and can be adapted by the USGS and others for specialized experiments with non-standard requirements. The software is continuously being updated and revised as improvements are required. The most recent revision may be downloaded from: http://woodshole.er.usgs.gov/operations/stg/Pubs/ADCPtools/adcp_index.htm The USGS makes this software available at the user?s discretion and responsibility.

Open-File Report↗
USGS2006

Hydrogeologic framework refinement, ground-water flow and storage, water-chemistry analyses, and water-budget components of the Yuma area, southwestern Arizona and southeastern California

The ground-water and surface-water system in the Yuma area in southwestern Arizona and southeastern California is managed intensely to meet water-delivery requirements of customers in the United States, to manage high ground-water levels in the valleys, and to maintain treaty-mandated water-quality and quantity requirements of Mexico. The following components in this report, which were identified to be useful in the development of a ground-water management model, are: (1) refinement of the hydrogeologic framework; (2) updated water-level maps, general ground-water flow patterns, and an estimate of the amount of ground water stored in the mound under Yuma Mesa; (3) review and documentation of the ground-water budget calculated by the Bureau of Reclamation, U.S. Department of the Interior (Reclamation); and (4) water-chemistry characterization to identify the spatial distribution of water quality, information on sources and ages of ground water, and information about the productive-interval depths of the aquifer. A refined three-dimensional digital hydrogeologic framework model includes the following hydrogeologic units from bottom to top: (1) the effective hydrologic basement of the basin aquifer, which includes the Pliocene Bouse Formation, Tertiary volcanic and sedimentary rocks, and pre-Tertiary metamorphic and plutonic rocks; (2) undifferentiated lower units to represent the Pliocene transition zone and wedge zone; (3) coarse-gravel unit; (4) lower, middle, and upper basin fill to represent the upper, fine-grained zone between the top of the coarse-gravel unit and the land surface; and (5) clay A and clay B. Data for the refined model includes digital elevation models, borehole lithology data, geophysical data, and structural data to represent the geometry of the hydrogeologic units. The top surface of the coarse-gravel unit, defined by using borehole and geophysical data, varies similarly to terraces resulting from the down cutting of the Colorado River. Clay A is nearly the same as the previous conceptual hydrogeologic model definition (Olmsted and others, 1973), except for a minor westward extension from the city of Yuma. Clay B is extended to the southerly international boundary and increased in areal extent by about two-thirds of the original extent (Olmsted and others, 1973). The other hydrogeologic units generally are the same as in the previous conceptual hydrogeologic model. Before development, the Colorado and Gila Rivers were the sources of nearly all the ground water in the Yuma area through direct infiltration of water from river channels and annual overbank flooding. After construction of upstream reservoirs and clearing and irrigation of the floodplains, the rivers now act as drains for the ground water. Ground-water levels in most of the Yuma area are higher now than they were in predevelopment time. A general gradient of ground-water flow toward the natural discharge area south of the Yuma area still exists, but many other changes in flow are evident. Ground water in Yuma Valley once flowed away from the Colorado River, but now has a component of flow towards the river and Mexicali Valley. A ground-water mound has formed under Yuma Mesa from long-term surface-water irrigation; about 600,000 to 800,000 acre-ft of water are stored in the mound. Ground-water withdrawals adjacent to the southerly international boundary have resulted in water-level declines in that area. The reviewed and documented water budget includes the following components: (1) recharge in irrigated areas, (2) evapotranspiration by irrigated crops and phreatophytes, (3) ground-water return flow to the Colorado River, and (4) ground-water withdrawals (including those in Mexicali Valley). Recharge components were calculated by subtracting the amount of water used by crops from the amount of water delivered. Evapotranspiration rates were calculated on the basis of established methods, thus were appropriate for input to the ground-water flow model developed by the Bureau of Reclamation (William Greer, hydrologist, Bureau of Reclamation, written commun., 2005). Evapotranspiration by crops and phreatophytes were calculated by using crop coefficient methods and meteorological data. Other methods of calculating evapotranspiration rates by using combinations of satellite imagery and ground-based data could be used for higher spatial and temporal resolution. Ground-water return flow during years of low flow on the Colorado River (1972–82, 1987–92, and 1994–96) averaged 79,000 acre-ft per year. Ground-water withdrawal data for 1970–99 were similar to other estimates made by the U.S. Geological Survey for the Yuma area. New water-chemistry data were collected in 12 wells and 8 canals/drains to characterize spatial patterns in chemical constituents, determine isotopic ages of water, infer possible sources of ground water, and locate the vertical intervals of the aquifer that contribute most water to wells. Depth-dependent samples were collected at one of the wells (YM-10). A large quantity of water-quality data were compiled from Bureau of Reclamation and U.S. Geological Survey records and merged into the U.S. Geological Survey National Water Information System database. New samples were analyzed for major ions, nutrients, stable isotopes of oxygen and hydrogen, tritium ( 3 H), and carbon-14 ( 14 C) (along with C 13 /C 12 ratios). Light values of oxygen-18 ( 18 O) and deuterium ( 2 H, D) in well 242-2 indicate recharge from the Colorado River. Heavy water samples from wells 242-22, CADC, and Mesa del Sol indicate local recharge sources. Tritium data indicate there is young water in wells in the valleys and near the edge of Yuma Mesa, while older water is found far from the Colorado River. 14 C data indicate that water from wells near the southerly international boundary is at least several thousand years old.

Arizona, California↗
USGS2013

Methods to assess geological CO 2 storage capacity: Status and best practice

To understand the emission reduction potential of carbon capture and storage (CCS), decision makers need to understand the amount of CO 2 that can be safely stored in the subsurface and the geographical distribution of storage resources. Estimates of storage resources need to be made using reliable and consistent methods. Previous estimates of CO 2 storage potential for a range of countries and regions have been based on a variety of methodologies resulting in a correspondingly wide range of estimates. Consequently, there has been uncertainty about which of the methodologies were most appropriate in given settings, and whether the estimates produced by these methods were useful to policy makers trying to determine the appropriate role of CCS. In 2011, the IEA convened two workshops which brought together experts for six national surveys organisations to review CO 2 storage assessment methodologies and make recommendations on how to harmonise CO 2 storage estimates worldwide. This report presents the findings of these workshops and an internationally shared guideline for quantifying CO 2 storage resources.

Report↗
USGS1956

Summary of reconnaissance for radioactive deposits in Alaska, 1945-1954, and an appraisal of Alaskan uranium possibilities

In the period 1945-1954 over 100 investigations for radioactive source materials were made in Alaska. The nature of these investigations ranged from field examinations of individual prospects or the laboratory analysis of significantly radioactive samples submitted by prospectors to reconnaissance studies of large districts. In this period no deposits of uranium or thorium that would warrant commercial exploitation were discovered. The investigations, however, disclosed that radioactive materials occur in widely scattered areas of Alaska and in widely diverse environments. Many igneous rocks throughout Alaska are weakly radioactive because of uranium- and thorium-bearing accessory minerals, such as allanite, apatite, monazite, sphene, xenotime, and zircon; more rarely the radioactivity of these rocks is due to thorianite or thorite and their uranoan varieties. The felsic rocks, for example, granites and syenites, are generally more radioactive than the mafic igneous rocks. Pegmatites, locally, have also proved to be radioactive, but they have little commercial significance. No primary uranium oxide minerals have been found yet in Alaskan vein deposits, except, perhaps, for a mineral tentatively identified as pitchblende in the Hyder district of southeastern Alaska. However, certain occurrences of secondary uranium minerals, chiefly those of the uranite group, on the Seward Peninsula, in the Russian Mountains, and in the vicinity of Kodiak suggest that pitchblende-type ores may occur at depth beneath zones of alteration. Thorite-bearing veins have been discovered on Prince of Wales Island in southeastern Alaska. Although no deposits or carnotite-type minerals have been found in Alaska, several samples containing such minerals have been submitted by Alaskan prospectors. Efforts to locate the deposits from which these minerals were obtained have been unsuccessful, but review of available geologic data suggests that several Alaskan areas are potentially favorable for carnotite-type deposits. The chief of these areas is the Alaska Peninsula-Cook Inlet area which encompasses most of the reported occurrences of the prospectors' carnotite-type samples. Alaska is also potentially favorable for the occurrence of large bodies of the very low-grade uraniferous sedimentary rocks, such as phosphorites and black shales. This type of deposit, however, has not received much study because of the emphasis on the search for bonanza-type high-grade ores. Uraniferous phosphorites similar to those of Idaho, Montana, and Wyoming occur in northern Alaska on the north flank of the Brooks Range; black shales comparable to the uraniferous shales of the Chattanooga formation of southeastern United States have been noted along the Yukon River near the international boundary. Placer deposits in Alaska have some small potential for the production of the radioactive elements as byproducts of gold- and tin-placer mining. the placer area believed to have the relatively greatest potential in Alaska lies in the Kahiltna River valley where concentrates are known to contain such commercial minerals as ilmenite, cassiterite, platinum, and gold in addition to uranothorianite and monazite. The possibilities of the natural fluids--water and petroleum--have not yet been tested in Alaska to any great extent. Studies of fluids are in progress to determine whether they may be used to discover and define areas potentially favorable for the occurrence of uraniferous lodes.

Alaska↗
USGS2018

On the petrographic distinction of bituminite from solid bitumen in immature to early mature source rocks

The oil-prone maceral bituminite (and its equivalents: ‘amorphous organic matter’, ‘sapropelinite’, ‘amorphinite’, etc.) converts to petroleum during thermal maturation of source rocks, resulting in formation of a mobile saturate-rich hydrocarbon and a polar-rich residue of solid bitumen. Evidence of this transition is preserved in immature to early mature source rocks (e.g., Alum, Bakken, Kimmeridge, New Albany, Ohio shales, among many others), where organic petrography reveals a continuum of textures, reflectance, and fluorescence intensity occurring between bituminite and solid bitumen. Bituminite generally is characterized by high(er) intensity fluorescence, low contrast to the inorganic matrix, lower reflectance (compared to solid bitumen), and heterogeneous wispy or ‘schlieren’ textures. In comparison, solid bitumen generally shows lower intensity or no fluorescence compared to bituminite, a distinct contrast to the mineral matrix which usually includes a gray homogeneous surface of low to moderate reflectance, and may possess void-filling, embayment or groundmass textures suggesting evidence of migration or its in situ exsolution. However, these properties may manifest across a continuous spectrum in a sample or in a single microscope field, often making identification inconclusive. Unambiguous identification is further hampered by sample preparation, e.g., mechanical polish may improve homogeneity of larger accumulations, whereas smaller accumulations, or those sheltered by hard minerals, may appear more heterogeneous, leading to identification of the same organic matter as solid bitumen or bituminite, respectively. The disruptive innovation of ion milling in shale sample preparation leads to increased organic reflectance and surface homogeneity, causing bituminite and other oil-prone macerals, e.g., alginite, to develop a gray reflecting surface which is easy to confuse with solid bitumen, especially when obvious void-filling or embayment textures of the latter are absent. Herein we review distinction of solid bitumen from bituminite and alginite in immature to early mature source rocks, providing examples from nine samples illustrated by typical organic petrography images, including samples from hydrous pyrolysis experiments. Based on a review of the literature, we observe an arbitrary reflectance limit of 0.30% in mechanically polished samples seems to differentiate bituminite (<0.30%) from confident identifications of homogeneous solid bitumen (which otherwise lacks obvious void-filling or identifying embayment textures) as individual macerals on a continuous spectrum in immature and early mature source rocks. Future work conducted by governing bodies such as the International Committee for Coal and Organic Petrology (ICCP) should consider interlaboratory studies conducted on multiple immature source rock samples to develop consensus guidelines for bituminite and solid bitumen discrimination.

International Journal of Coal Geology↗
USGS2009

Toward production from gas hydrates: Current status, assessment of resources, and simulation-based evaluation of technology and potential

Gas hydrates (GHs) are a vast energy resource with global distribution in the permafrost and in the oceans. Even if conservative estimates are considered and only a small fraction is recoverable, the sheer size of the resource is so large that it demands evaluation as a potential energy source. In this review paper, we discuss the distribution of natural GH accumulations, the status of the primary international research and development (R&D) programs, and the remaining science and technological challenges facing the commercialization of production. After a brief examination of GH accumulations that are well characterized and appear to be models for future development and gas production, we analyze the role of numerical simulation in the assessment of the hydrate-production potential, identify the data needs for reliable predictions, evaluate the status of knowledge with regard to these needs, discuss knowledge gaps and their impact, and reach the conclusion that the numerical-simulation capabilities are quite advanced and that the related gaps either are not significant or are being addressed. We review the current body of literature relevant to potential productivity from different types of GH deposits and determine that there are consistent indications of a large production potential at high rates across long periods from a wide variety of hydrate deposits. Finally, we identify (a) features, conditions, geology and techniques that are desirable in potential production targets; (b) methods to maximize production; and (c) some of the conditions and characteristics that render certain GH deposits undesirable for production. Copyright ?? 2009 Society of Petroleum Engineers.

Conference Paper↗
USGS1986

Seismic measurements of the internal properties of fault zones

The internal properties within and adjacent to fault zones are reviewed, principally on the basis of laboratory, borehole, and seismic refraction and reflection data. The deformation of rocks by faulting ranges from intragrain microcracking to severe alteration. Saturated microcracked and mildly fractured rocks do not exhibit a significant reduction in velocity, but, from borehole measurements, densely fractured rocks do show significantly reduced velocities, the amount of reduction generally proportional to the fracture density. Highly fractured rock and thick fault gouge along the creeping portion of the San Andreas fault are evidenced by a pronounced seismic low-velocity zone (LVZ), which is either very thin or absent along locked portions of the fault. Thus there is a correlation between fault slip behavior and seismic velocity structure within the fault zone; high pore pressure within the pronounced LVZ may be conductive to fault creep. Deep seismic reflection data indicate that crustal faults sometimes extend through the entire crust. Models of these data and geologic evidence are consistent with a composition of deep faults consisting of highly foliated, seismically anisotropic mylonites.

Pure and Applied Geophysics PAGEOPH↗