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At least 109 records · Page 6Linked to original sources
USGS2016

Book review: New concepts and discoveries: the Geological Society of Nevada 2015 Symposium Proceedings

The Nevada Geological Society has a long history of convening meetings and workshops focused on the geology and metallogeny of the western United States relevant to the mineral exploration and mining community across the Great Basin. One outgrowth of the Geological Society of Nevada’s 2015 Symposium is a two-volume set, edited by W.M. Pennell and L.J. Garside, entitled New Concepts and Discoveries . The symposium was held in Sparks, Nevada, May 14–23, 2015, with more than 1,000 attendees, 59 talks in 10 thematic sessions, 7 field trips, and 10 short courses, all focused on serving the geologic, exploration, and mining community. The attractively produced, hardbound, two-volume set includes a CD-ROM containing all the manuscripts as well as numerous abstracts from presentations arranged by the thematic session in which they were presented. The papers range from detailed case study descriptions of individual deposits to important syntheses covering the geologic evolution and resulting metallogeny of the Great Basin and beyond.

Economic Geology↗
USGS2020

Book review: Rare earth element resources: Indian context

Rare Earth Element Resources: Indian Context. Yamuna Singh. 2020. ISBN 978-3-030-41353-8. Society of Earth Scientists Series, Springer, Cham, Switzerland, 269 Pp. Hardcover and eBook. €93.08 Rare Earth Element Resources: Indian Context by Yamuna Singh provides an excellent review of rare earth element (REE) deposits and occurrences in India with an emphasis on placer deposits, India’s most notable REE resource. This 269-page, 10-chapter book not only describes REE occurrences but also provides introductory material on REE geochemistry and discusses other potential industrial sources including recycling, fly ash, and mine waste products. The book concludes with a chapter on the state of the REE industry in India and discusses possible future trends and needs. Anyone interested in exploring for REEs in India will find this book from Springer’s Society of Earth Scientists series a useful reference.

Economic Geology↗
USGS2015

Assessment of general health of fishes collected at selected sites in the Great Lakes Basin In 2012

During the past decade, there has been a substantive increase in the detection of “emerging contaminants”, defined as a new substance, chemical, or metabolite in the environment; or a legacy substance with a newly expanded distribution, altered release, or a newly recognized effect (such as endocrine disruption). Emerging contaminants include substances such as biogenic hormones (human and animal), brominated flame retardants, pharmaceuticals, personal care products, plasticizers, current use pesticides, detergents, and nanoparticles. These contaminants are frequently not regulated or inadequately regulated by state or Federal water quality programs. Information about the toxicity of these substances to fish and wildlife resources is generally limited, compared to more highly regulated contaminants, and some classes have been shown to cause affects (for example feminization of male fish, immunomodulation) that are not evaluated via traditional toxicity testing protocols. As a result, these compounds may pose a substantial, but currently poorly documented threat to aquatic ecosystems. Failure to identify and understand the impacts of these emerging contaminants on fish and wildlife resources may result in deleterious impacts to Great Lakes resources that can result in adverse ecological, economic and recreational consequences. The U. S. Fish and Wildlife Service received funding through the Great Lakes Restoration Initiative (GLRI) for an Early Warning Program to detect and identify emerging contaminants and to evaluate the effects of these contaminants on fish and wildlife. The U.S. Geological Survey (WV Cooperative Fish and Wildlife Research Unit and National Fish Health Research Laboratory, Leetown Science Center) developed and implemented a biological effects monitoring protocol to assist in this program. Fish collections and measurements of biomarkers of exposure in Fall 2010 and Spring 2011 occurred at individual sites within select Areas of Concern (AOCs). They provided an assessment of the utility of the suite of biomarkers and also identified sites for more in-depth analyses. Selected areas are characterized as areas with known emerging contaminants, sensitive or listed species, areas downstream from municipal wastewater discharges or receiving waters for industrial facilities, and/or areas susceptible to agricultural or urban contamination, or harbors or ports. The results of the 2010- 2011 studies were summarized in Blazer et al. 2014 a, b, c; Braham et al. in review and Blazer et al. in review.

Great Lakes↗
USGS1949

Research in coal paleobotany since 1943

The varied applications of paleobotany to coal resource studies, coal technology, and to fundamental physical and chemical research on coal are briefly indicated. The usual conception of paleobotany is not as broad as this, and many of the studies of fossil plants have been conducted without reference to the part the plant materials assume in composing coal. The interrelationship of paleobotany with the physical constitution and petrography of coal is an intimate one. which is too involved for treatment in the present paper. Chief emphasis is devoted to review of plant microfossil investigations during the past several years.The consistent abundance of plant microfossils in coal and its associated rocks is now generally recognized. One of the greatest difficulties in using this material for correlation and for extending our knowledge of the plant composition of coal has been in systematic (taxonomic) treatment of the materials. The reviews of recent literature are presented chiefly with reference to the diverse systematic approaches of various authors. The contrast between essentially nonbotanical or morphologic classification schemes, which are simpler to apply and which may serve adequately for local correlational studies, and those studies conceived on a more fundamental basis of plant taxonomy, for paleogeographic and ecologic interpretation of botanically related groups, is presented. Both viewpoints should be kept clearly in mind, since differing circumstances of study and differing objectives may suggest the advisability of using one rather than the other method of systematic treatment of these fossils. No other fossils are so conveniently available from the coal deposits of primary interest.

Economic Geology↗
USGS2022

2021 assessment of the Joint Fire Science Program’s Fire Science Exchange Network

The U.S. Geological Survey (USGS), on behalf of the Joint Fire Science Program (JFSP), conducted an evaluation of the Fire Science Exchange Network (FSEN), which connects wildland fire scientists and practitioners through 15 individual exchanges across the United States to help address complex wildfire needs and challenges. The study was divided into two phases: The first phase was a literature review and synthesis from materials provided by the JFSP Board. Phase two, informed by the JFSP review, was an online survey sent to more than 16,000 exchange network users compiled from the electronic mailing lists for each exchange. Respondents were asked their opinions on the importance, quality, and delivery of information for 16 key fire science topics, the prioritization of FSEN objectives, and from where and to what extent respondents are gathering information on key topics. Overall, respondents believed that sharing information and building relationships are the most important objectives of the FSEN. Respondents believed the exchange network is successful in delivering information for many of the key science topics (for example, fire behavior, prescribed fire, firefighter safety, and incident management); gaps were identified in scientific resources available for some topics (for example, economic impacts, social science and human dimensions, Indigenous knowledge). Most respondents participated in one to two exchanges and relied heavily on their respondent location (the exchange in which they primarily live and [or] work) for information. Respondents also often relied on external sources outside of the exchange network. Regional patterns emerged in information gathering whereby respondents from exchanges in the western United States (for example, Northern Rockies, Southern Rockies, and Northwest) and respondents from exchanges in the eastern United States (for example, Southern, Oak Woodlands, and Tallgrass) frequently gathered information from each other.

Scientific Investigations Report↗
USGS2008

Applying the land use portfolio model to estimate natural-hazard loss and risk — A hypothetical demonstration for Ventura County, California

With costs of natural disasters skyrocketing and populations increasingly settling in areas vulnerable to natural hazards, society is challenged to better allocate its limited risk-reduction resources. In 2000, Congress passed the Disaster Mitigation Act, amending the Robert T. Stafford Disaster Relief and Emergency Assistance Act (Robert T. Stafford Disaster Relief and Emergency Assistance Act, Pub. L. 93-288, 1988; Federal Emergency Management Agency, 2002, 2008b; Disaster Mitigation Act, 2000), mandating that State, local, and tribal communities prepare natural-hazard mitigation plans to qualify for pre-disaster mitigation grants and post-disaster aid. The Federal Emergency Management Agency (FEMA) was assigned to coordinate and implement hazard-mitigation programs, and it published information about specific mitigation-plan requirements and the mechanisms (through the Hazard Mitigation Grant Program-HMGP) for distributing funds (Federal Emergency Management Agency, 2002). FEMA requires that each community develop a mitigation strategy outlining long-term goals to reduce natural-hazard vulnerability, mitigation objectives and specific actions to reduce the impacts of natural hazards, and an implementation plan for those actions. The implementation plan should explain methods for prioritizing, implementing, and administering the actions, along with a 'cost-benefit review' justifying the prioritization. FEMA, along with the National Institute of Building Sciences (NIBS), supported the development of HAZUS ('Hazards U.S.'), a geospatial natural-hazards loss-estimation tool, to help communities quantify potential losses and to aid in the selection and prioritization of mitigation actions. HAZUS was expanded to a multiple-hazard version, HAZUS-MH, that combines population, building, and natural-hazard science and economic data and models to estimate physical damages, replacement costs, and business interruption for specific natural-hazard scenarios. HAZUS-MH currently performs analyses for earthquakes, floods, and hurricane wind. HAZUS-MH loss estimates, however, do not account for some uncertainties associated with the specific natural-hazard scenarios, such as the likelihood of occurrence within a particular time horizon or the effectiveness of alternative risk-reduction options. Because of the uncertainties involved, it is challenging to make informative decisions about how to cost-effectively reduce risk from natural-hazard events. Risk analysis is one approach that decision-makers can use to evaluate alternative risk-reduction choices when outcomes are unknown. The Land Use Portfolio Model (LUPM), developed by the U.S. Geological Survey (USGS), is a geospatial scenario-based tool that incorporates hazard-event uncertainties to support risk analysis. The LUPM offers an approach to estimate and compare risks and returns from investments in risk-reduction measures. This paper describes and demonstrates a hypothetical application of the LUPM for Ventura County, California, and examines the challenges involved in developing decision tools that provide quantitative methods to estimate losses and analyze risk from natural hazards.

California↗
USGS2016

Economic consequence analysis of the Arkstorm scenario

The business interruption (BI) impacts of ARkStorm, a severe winter storm scenario developed by the U.S. Geological Survey and partners, is estimated. BI stems from losses of building function, productivity of agricultural land, and lifeline services. A dynamic computable general equilibrium model of the California economy is developed to perform this economic consequence analysis. Economic resilience in the form of input and import substitution is inherent in the model’s equilibrium solution, and the model parameterization is adjusted to reflect other forms of resilience such as production recapture. Varying assumptions about the timing and source of funds for reconstruction results in a range of recovery paths. Five years after the storm, flood-induced building damage is the overwhelming source of gross domestic product (GDP) losses, timely and partially externally funded reconstruction mitigates impacts by approximately 50%, and the economy is not guaranteed to return to its baseline GDP trajectory. The methodology serves as a template for assessing the macroeconomic consequences of disasters and the influence of resilience in reducing BI losses.

National Hazards Review↗
USGS1929

Geology of the De Queen and Caddo Gap quadrangles, Arkansas

The field study of the geology of the De Queen and Caddo Gap quadrangles extended over a period of many years, and although the scientific and economic results from the study are here set forth fully for the first time in a single report, a number of publications have been issued that have presented some of the more important results. The field work was begun in 1907 and continued intermittently until 1925. The work in 1907 was done under a cooperative agreement between the United States Geological Survey and the Arkansas Geological Survey and involved primarily an investigation of the slate deposits of west-central Arkansas but also the mapping of the rocks in the mountainous part of the Caddo Gap quadrangle. In that year A. H. Purdue, State geologist of Arkansas, had charge of the work and was assisted by R. D. Mesler and H. D. Miser. All the subsequent work in the Caddo Gap quadrangle, as well as all in the De Queen quadrangle, was done by the United States Geological Survey. The work since 1907 is briefly outlined below. In 1908 Mr. Purdue, assisted by Mr. Miser, completed the mapping of the rocks of the Caddo Gap quadrangle with the aid of valuable suggestions from C. W. Hayes, chief geologist, J. A. Taff, and E. O. Ulrich, who visited the field for several days. In 1910 Mr. Purdue, assisted by Mr. Miser, reviewed a part of the previous work in the Caddo Gap quadrangle and mapped the rocks in most of the mountainous portion of the De Queen quadrangle. In 1911 these geologists did additional work in both the De Queen and Caddo Gap quadrangles, and in 1912 Mr. Miser, assisted by Mr. Mesler, completed the mapping of the rocks in the De Queen quadrangle and then reviewed some of the earlier work in the Caddo Gap quadrangle. In 1913 Arthur Keith, and Messrs. Purdue and Miser spent several days in a field conference in the Caddo Gap quadrangle. During the conference the first identifiable fossils in the Blaylock sandstone, of Silurian age, were discovered. In 1914 Mr. Miser obtained a small collection of fossil plants from the Stanley shale near Gillham, Ark., also the first fossils from the Arkansas novaculite. In 1916 he made a special study of some of the mineral deposits of the quadrangles, including the deposits of diamonds, manganese ore, gravel, and asphalt, and in 1917 he revisited the diamond mines. An investigation of the volcanic ash and tuff in the "Bingen formation," of Upper Cretaceous age, in the Caddo Gap quadrangle and adjoining areas to the south and southwest was made in 1923 by Clarence S. Ross and Mr. Miser. Also in that year other fossil plants were collected from the Stanley shale at the earlier discovered locality near Gillham by Mr. Miser. (See pl. 9, A .) The aggregate time spent in collecting fossils at this locality was eight days, so scare are the fossils and so difficult are the conditions for collecting them. Besides the above work the authors made frequent reconnaissance studies of adjoining areas, and Mr. Miser was joined in 1923 by C. W. Honess for a field conference of a few days in the De Queen and Caddo Gap quadrangles. In 1925 Mr. Miser joined in the field Messrs. L. W. Stephenson and C. H. Dane for a few days in a study of the " Bingen " (Woodbine and Tokio) and other formations of Upper Cretaceous age in and near the Caddo Gap quadrangle. Mr. Dane was making at that time a special study of the deposits of Upper Cretaceous age in southwestern Arkansas under a cooperative agreement between the United States Geological Survey and the Arkansas Geological Survey. For some of the information on the Tokio formation the present writers are indebted to Mr. Dane.

Arkansas, Oklahoma↗
USGS2010

A portfolio approach to evaluating natural hazard mitigation policies: An application to lateral-spread ground failure in coastal California

In the past, efforts to prevent catastrophic losses from natural hazards have largely been undertaken by individual property owners based on site—specific evaluations of risks to particular buildings. Public efforts to assess community vulnerability and encourage mitigation have focused on either aggregating site—specific estimates or adopting standards based upon broad assumptions about regional risks. This paper develops an alternative, intermediate—scale approach to regional risk assessment and the evaluation of community mitigation policies. Properties are grouped into types with similar land uses and levels of hazard, and hypothetical community mitigation strategies for protecting these properties are modeled like investment portfolios. The portfolios consist of investments in mitigation against the risk to a community posed by a specific natural hazard. and are defined by a community's mitigation budget and the proportion of the budget invested in locations of each type. The usefulness of this approach is demonstrated through an integrated assessment of earthquake—induced lateral—spread ground failure risk in the Watsonville, California area. Data from the magnitude 6.9 Loma Prieta earthquake of 1989 are used to model lateral—spread ground failure susceptibility. Earth science and economic data are combined and analyzed in a Geographic Information System (CIS). The portfolio model is then used to evaluate the benefits of mitigating the risk in different locations. Two mitigation policies, one that prioritizes mitigation by land use type and the other by hazard zone, are compared with a status quo policy of doing no further mitigation beyond that which already exists. The portfolio representing the hazard zone rule yields a higher expected return than the land use portfolio does; however, the hazard zone portfolio experiences a higher standard deviation. Therefore, neither portfolio is clearly preferred. The two mitigation policies both reduce expected losses and increase overall expected community wealth compared to the status quo policy.

California↗
USGS2024

Machine learning approaches to identify lithium concentration in petroleum produced waters

Prices for battery-grade lithium have increased substantially since 2020, which is propelling the search for additional sources of this important element. Battery-grade lithium is predominately recovered from continental brines. Most crude oil and natural gas wells recover briny formation water, which may represent an additional source. Chemical analysis of these waters has been shown to indicate the presence of varying concentrations of lithium and related elements. This paper briefly reviews developments and literature supporting the presence of lithium in petroleum reservoir brines. It also describes the coverage and distribution of lithium data analyses in the United States Geological Survey National Produced Waters Geochemical Database (PWGD). It then addresses the question as to whether a lithium concentration can be accurately predicted using constituents of ion chemistry in produced brines from specific geologic formations. Four machine learning algorithms are employed to classify the commercial potential of lithium in oil field brines using data from oil wells recovering formation water from the Smackover Formation. The calibrated classification models are further applied to new (out-of-sample) data from the Marcellus Formation in the Appalachian Basin. Among the approaches considered, the predictive performance and wider applicability of the gradient boosted tree and the deep neural network models are determined to be the most promising. Finally, we discuss how the calibrated models could be applied to assure the quality of the data reported from chemical laboratory analysis and for imputation when lithium values are missing.

Mineral Economics↗
USGS2011

Book review: Hollowed ground—Copper mining and community building on Lake Superior, 1840s–1990s

In 1843, six years before the Forty-niners headed west for the goldfields of California, the United States’ first great mineral rush began to a land that was, as Patrick Henry told Congress, “beyond the most distant wilderness and remote as the moon.” He was referring to the Keweenaw Peninsula of northern Michigan. This rush was not for gold or silver, but for copper. And not just any copper, but native copper, so pure it required little refining before use. The early horde of fortune-seekers came with visions of finding mountains of solid copper, spurred on by stories of large masses of “float copper” that included the famous Ontonagon Boulder, a large mass of native copper originally found lying 32 km up the steep and rugged valley of the Ontonagon River (and now gathering dust in the Smithsonian Museum).

Economic Geology↗
USGS1955

Is Carbon dioxide an ore-forming fluid under shallow-earth conditions?

A review of some of the physical-chemical properties of CO 2 and of the system CO 2 --H 2 O indicates that under some shallow-earth conditions CO 2 can exist as a separate phase with a density approximately that of water. The effect of dissolved neutral or acid salts on the solubility of CO 2 in H 2 O is not large. Carbonates, oxides, and silicates, through reactions with a CO 2 -saturated water phase, will eventually cause the disappearance of a CO 2 phase. The prevalence of CO 2 in the earth's crust is attested by its abundance in natural gases and fluid inclusions in minerals. Some of the characteristics of uranium ores of the Colorado Plateau are not incompatible with the assumption that deposition was from a fluid CO 2 phase.

Economic Geology↗
USGS2018

Development of a domestic earthquake alert protocol combining the USGS pager and FEMA Hazus systems

The U.S. Geological Survey’s PAGER automated alert system provides rapid (10-20 min) loss estimates in terms of ranges of fatalities and economic impact for all significant earthquakes around the globe. In contrast, FEMA’s Hazus software, which is currently operated manually by FEMA personnel internally within several hours of any large domestic earthquake, provides more detailed loss information quantified in terms of physical damage to the building stock, as well as a broad range of social and economic consequences estimated at a much higher spatial resolution (census-tract level). Hazus was originally designed for FEMA’s mitigation planning, but has been used of late for post-earthquake situational awareness. While the quick alerts generated automatically by the PAGER system are a suitable way to initially identify consequences for earthquakes, there remains a need to provide detailed loss information for facilitating a wider array of post-earthquake decisions among emergency managers. As such, we have developed a prototype summary product that takes advantage of the benefits of both these loss models for significant domestic earthquakes. The signature product, a new twoPAGER report, will serve as a supplement to the widely deployed standard onePAGER product for all significant domestic earthquakes. Page one is the standard, automated PAGER alert content, with summary alert levels for overall fatality and economic loss estimates, as well as summary content on recent earthquakes, structure vulnerability, and historical secondary hazards. As soon as the Hazus run using the most up-to-date version of the USGS ShakeMap is completed and reviewed by both agencies, the second alert page will be generated and delivered via the USGS website as an update. This second page will contain a summary of the more comprehensive Hazus model results, including spatially distributed estimates of: affected population, economic impact, non-fatal injuries, displaced households, and damage to structures (including potential building safety evaluation requirements). This enhancement does not affect the timeliness and the importance of the initial (onePAGER) alerting content for significant earthquakes; however, the twoPAGER report will provide more detailed, damage and loss/impact content for the Nation in the critical hours following a damaging earthquake.

Conference Paper↗
USGS2016

Global stocks of selected mineral-based commodities

Introduction The U.S. Geological Survey, National Minerals Information Center, analyzes mineral and metal supply chains by identifying and describing major components of mineral and material flows from ore extraction, through intermediate forms, to a final product. This report focuses on an important component of the world’s supply chain: the amounts and global distribution of major consumer, producer, and exchange stocks of selected mineral commodities. In this report, the term “stock” is used instead of “inventory” and refers to accumulations of mined ore, intermediate products, and refined mineral-based commodities that are in a form that meets the agreed-upon specifications of a buyer or processor of intermediate products. These may include certain ores such as bauxite, concentrates, smelter products, and refined metals. Materials sometimes referred to as inventory for accounting purposes, such as ore contained in a deposit or in a leach pile, or materials that need to be further processed before they can be shipped to a consumer, are not considered. Stocks may be held (owned) by consumers, governments, investors, producers, and traders. They may serve as (1) a means to achieve economic, social, and strategic goals through government policies; (2) a secure source of supply to meet demand and to mitigate potential shortages in the supply chain; (3) a hedge to mitigate price volatility; and (4) vehicles for speculative investment. The paucity and uneven reliability of data for stocks of ores and concentrates and for material held by producers, consumers, and merchants hinder the accurate estimating of the size and distribution of this portion of the supply chain for certain commodities. This paper reviews the more visible stocks held in commodity exchange warehouses distributed throughout the world.

Scientific Investigations Report↗
USGS1981

A review of regional mineral resource assessment methods

Over 100 papers on regional mineral resource assessment of nonfuels are classified according to method(s) used and form(s) of product in order to help identify possible methods for future assessments. Types of products that have been used include: tons of metal; tons of rock and associated grade; gross value; potential; number of deposits; probability of one or more deposits; tons of rock, grade, and number of deposits by type; potential supply; and net value. Assessment methods considered are: time-rate, crustal abundance, cumulative tonnage versus grade, simple subjective, complex subjective, Bayesian, frequency, trend, geometric probability, multiple regression, discriminant analysis, modified component, multivariate logistic, cluster analysis or pattern recognition, and simulation.Selection of a method to be employed in an assessment should be based on: (1) appropriateness of the product to the problem, (2) limitations in resources, such as information or time available for the assessment, (3) the level of uncertainty and acceptability of biases in the assessment, and (4) the need for verification of results and acceptance of the method.

Economic Geology↗
USGS2015

Carbon dioxide storage in unconventional reservoirs workshop: summary of recommendations

“Unconventional reservoirs” for carbon dioxide (CO 2 ) storage—that is, geologic reservoirs in which changes to the rock trap CO 2 and therefore contribute to CO 2 storage—including coal, shale, basalt, and ultramafic rocks, were the focus of a U.S. Geological Survey (USGS) workshop held March 28 and 29, 2012, at the National Conservation Training Center in Shepherdstown, West Virginia. The goals of the workshop were to determine whether a detailed assessment of CO 2 storage capacity in unconventional reservoirs is warranted, and if so, to build a set of recommendations that could be used to develop a methodology to assess this storage capacity. Such an assessment would address only the technically available resource, independent of economic or policy factors. At the end of the workshop, participants agreed that sufficient knowledge exists to allow an assessment of the potential CO 2 storage resource in coals, organic-rich shales, and basalts. More work remains to be done before the storage resource in ultramafic rocks can be meaningfully assessed. In order to assess the CO 2 storage capacity of coals and organic-rich shales, the workshop participants agreed that the following several factors are key: sorption mechanisms and capacity, pore fluid composition and saturation, thermal maturity, formation thickness, and whether hydrocarbons have been extracted from the formation previously (for example, by enhanced gas or oil recovery). In order to assess the CO 2 storage capacity of basalts, the workshop participants agreed that key factors include temperature, pressure, pH, water chemistry, mineral chemistry, organic content, mineralogy, porosity, permeability, relative permeabilities, and CO 2 phase. The storage capacity for all unconventional reservoirs may be modeled using a volumetric equation starting with the extent of the rock unit and adjusted using these key factors and reaction terms. The ideas that were developed during this workshop can be used by USGS scientists to develop a methodology to assess the CO 2 storage resource in unconventional reservoirs. This methodology could then be released for public comment and peer review. After completing this development process, the USGS could then use the methodology to assess the CO 2 storage resource in unconventional reservoirs.

Open-File Report↗
USGS1969

Massive sulfide deposits and volcanism

Massive sulfide deposits, consisting of pyrite and/or pyrrhotite and various ratios of chalcopyrite, sphalerite, and galena, are commonly associated with volcanic rocks that accumulated in eugeosynclines. Later deformation may leave an imprint of regional metamorphism. Two-thirds of the deposits mentioned in this review are about equally divided between silicic and mafic volcanic host rocks, and the remainder occur in tuffaceous sedimentary rocks interbedded with volcanics. Little compelling evidence is available to relate genetically most of these deposits to granitic rocks, whereas considerable evidence supports a complex genetic relationship to volcanic rocks that accumulated in a submarine environment. Some deposits apparently formed during or soon after emplacement of the volcanic rocks, and possibly involved early deposition of pyrite that was followed later by the addition of base metals. The transporting agents of the base metals and some of the sulfur are heated solutions probably of different origins containing alkali chlorides as well as alkali chloride brines. Pyrite and base metals may have been deposited during the accumulation of the volcanic and associated rocks, or later during diagenesis, regional metamorphism, or intrusion of granitic plutons. The source of the base metals may have been: (1) early metal concentrations distributed through the volcanic pile, (2) trace quantities in the silicate minerals in the volcanics, or (3) later crystallizing magma.

Economic Geology↗
USGS2018

Annotated bibliography of scientific research on greater sage-grouse published since January 2015

The greater sage-grouse ( Centrocercus urophasianus ; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and determining the need for potential updates to existing planning documents. To assist in this process, the U.S. Geological Survey (USGS) has reviewed and summarized the scientific literature published since January 1, 2015. To identify articles and reports published about GRSG, we first conducted a structured search of three reference databases (Web of Science, Scopus, and Google Scholar) using the search term “greater sage-grouse.” We refined the initial list of products by (1) removing duplicates, (2) excluding products that were not published as research or scientific review articles in peer-reviewed journals or as formal government technical reports, and (3) retaining only those products for which GRSG or their habitat was a research focus. We summarized the contents of each product by using a consistent structure (background, objectives, methods, location, findings, and implications) and assessed the content of each product relevant to a list of 31 management topics. These topics include GRSG biology and habitat characteristics along with potential management actions, land uses, and environmental factors related to GRSG management and conservation. We also noted which articles/reports created new geospatial data. The final search was conducted on January 6, 2018, and application of our criteria resulted in the inclusion of 169 published products (2 of these products were published corrections to journal articles). The management topics most commonly addressed were GRSG behavior or demographics and GRSG habitat selection or habitat characteristics at broad or site scales. Few products addressed captive breeding, recreation, wild horses and burros, and range management structures (including fences). We include in this annotated bibliography the full citation, product summary, and management topics addressed by each product. The online version of this bibliography ( https://apps.usgs.gov/gsgbib/index.php ) is searchable by topic and location and includes links to the original publications. A substantial body of literature has been compiled based on research explicitly related to the conservation, management, monitoring, and assessment of GRSG. These studies may inform planning and management actions that seek to balance conservation, economic, and social objectives and manage diverse resource uses and values across the western United States. The review process for this product included requesting input on each summary from one or more authors of the original peer-reviewed article or report and a formal review of the entire document by three independent reviewers and, subsequently, the USGS Bureau Approving Official. This process is consistent with USGS Fundamental Science Practices.

Open-File Report↗