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At least 73 records · Page 4Linked to original sources

USGS2022

The over-prediction of seismically induced soil liquefaction during the 2016 Kumamoto, Japan earthquake sequence

Following the M7.0 strike-slip earthquake near Kumamoto, Japan, in April of 2016, most geotechnical engineering experts believed that there would be significant soil liquefaction and liquefaction-induced infrastructure damage observed in the densely populated city of Kumamoto during the post-event engineering reconnaissance. This belief was driven by several factors including the young geologic environment, alluvially deposited soils, a predominance of loose sandy soils documented in publicly available boring logs throughout the region, and the high intensity ground motions observed from the earthquake. To the surprise of many of the researchers, soil liquefaction occurred both less frequently and less severely than expected. This paper summarizes findings from our field, laboratory, and simplified analytical studies common to engineering practice to assess the lower occurrence of liquefaction. Measured in situ SPT and CPT resistance values were evaluated with current liquefaction triggering procedures. Minimally disturbed samples were subjected to cyclic triaxial testing. Furthermore, an extensive literature review on Kumamoto volcanic soils was performed. Our findings suggest that current liquefaction triggering procedures over-predict liquefaction frequency and effects in alluvially deposited volcanic soils. Volcanic soils were found to possess properties of soil crushability, high fines content, moderate plasticity, and unanticipated organic constituents. Cyclic triaxial tests confirm the high liquefaction resistance of these soils. Moving forward, geotechnical engineers should holistically consider the soil’s mineralogy and geology before relying solely on simplified liquefaction triggering procedures when evaluating volcanic soils for liquefaction.

Mount Aso↗

USGS2013

Origin of the Sinai-Negev erg, Egypt and Israel: mineralogical and geochemical evidence for the importance of the Nile and sea level history

The Sinai–Negev erg occupies an area of 13,000 km 2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative to K-feldspar and plagioclase. However, Sinai wadi sands have abundant calcite, whereas Nile Delta sands have little or no calcite. Overall, the mineralogical data suggest that the dunes are derived dominantly from the Nile Delta, with Sinai wadi sands being a minor contributor. Geochemical data that proxy for both the light mineral fraction (SiO 2 /10–Al 2 O 3 + Na 2 O + K 2 O–CaO) and heavy mineral fraction (Fe 2 O 3 –MgO–TiO 2 ) also indicate a dominant Nile Delta source for the dunes. Thus, we report here the first empirical evidence that the Sinai–Negev dunes are derived dominantly from the Nile Delta. Linkage of the Sinai–Negev erg to the Nile Delta as a source is consistent with the distribution of OSL ages of Negev dunes in recent studies. Stratigraphic studies show that during the Last Glacial period, when dune incursions in the Sinai–Negev erg began, what is now the Nile Delta area was characterized by a broad, sandy, minimally vegetated plain, with seasonally dry anastomosing channels. Such conditions were ideal for providing a ready source of sand for aeolian transport under what were probably much stronger glacial-age winds. With the post-glacial rise in sea level, the Nile River began to aggrade. Post-glacial sedimentation has been dominated by fine-grained silts and clays. Thus, sea level, along with favorable climatic conditions, emerges as a major influence on the timing of dune activity in the Sinai–Negev erg, through its control on the supply of sand from the Nile Delta. The mineralogy of the Sinai–Negev dunes is also consistent with a proposed hypothesis that these sediments are an important source of loess in Israel.

Sinai-negev Erg↗

USGS2010

El Salvador, Chile porphyry copper deposit revisited: Geologic and geochronologic framework

The Eocene (42 to 41 Ma) El Salvador porphyry copper deposit in the Indio Muerto district, northern Chile (26° 15′ S Lat.), formerly thought to have formed at the culmination of a 9-m.y. period of episodic magmatism, is shown by new mapping, U-Pb and K-Ar geochronology, and petrologic data to have formed during the younger of two distinct but superposed magmatic events-a Paleocene (∼63 to 58 Ma) and an Eocene (44 to 41 Ma) event. In the district, high-K Paleocene volcano-plutonic activity was characterized by a variety of eruptive styles and magmatic compositions, including a collapse caldera associated with explosive rhyolitic magmatism (El Salvador trapdoor caldera), a post-collapse rhyolite dome field (Cerro Indio Muerto), and andesitic-trachyandesitic stratovolcanos (Kilometro Catorce-Los Amarillos sequence). Pre-caldera basement faults were reactivated during Paleocene volcanism as part of the collapse margin of the caldera. Beneath Cerro Indio Muerto, where the porphyry Cu deposit subsequently formed, the intersection of two major basement faults and the NNE-striking rotational axis of tilted ignimbrites of the Paleocene El Salvador caldera localized emplacement of post-collapse rhyolite domes and peripheral dikes and sills. Subsequent Eocene rhyolitic and granodioritic-dacitic porphyries intruded ~14 m.y. after cessation of Paleocene magmatism along the same NNE-striking structural belt through Cerro Indio Muerto as did the post-collapse Paleocene rhyolite domes. Eocene plutonism over a 3-m.y. period was contemporaneous with NW-SE-directed shortening associated with regional sinistral transpression along the Sierra Castillo fault, lying ∼10 km to the east. Older Eocene rhyolitic porphyries in the Indio Muerto district were emplaced between 44 and 43 Ma, and have a small uneconomic Cu center associated with a porphyry at Old Camp. The oldest granodioritic-dacitic porphyries also were emplaced at ∼44 to 43 Ma, but their petrogenetic relation to the rhyolitic porphyries and younger granodioritic-dacitic porphyries in the district is unclear. The main porphyry Cu-Mo-related granodioritic-dacitic stocks in Quebrada Turquesa on Cerro Indio Muerto intruded, cooled, and were mineralized within ∼1 m.y. between 42 and 41 Ma. Volumetrically minor late- to post-mineral porphyries are slightly more mafic than earlier granodioritic-dacitic porphyries, a compositional trend possibly repeated on several scales and more than once over the 3-million-year Eocene magmatic history of the Indio Muerto district. This compositional trend requires either addition of basaltic material into an open-system silicic magma chamber or tapping of progressively deeper levels of a vertically zoned magma chamber. Eocene porphyry magmas were more hydrous and their residual source mineralogy richer in garnet than the relatively anhydrous Paleocene rocks, whose source was rich in pyroxene. The presence of inherited zircons in Paleocene and Eocene rocks requires interaction with crustal rocks of Paleozoic and/or Proterozoic age.

International Geology Review↗

USGS2018

Compositional variation in the chevkinite group: new data from igneous and metamorphic rocks

Electron microprobe analyses are presented of chevkinite-group minerals from Canada, USA, Guatemala, Norway, Scotland, Italy and India. The host rocks are metacarbonates, alkaline and subalkaline granitoids, quartz-bearing pegmatites, carbonatite and an inferred K-rich tuff. The analyses extend slightly the range of compositions in the chevkinite group, e.g. the most MgO-rich phases yet recorded, and we report two further examples where La is the dominant cation in the A site. Patchily- zoned crystals from Virginia and Guatemala contain both perrierite and chevkinite compositions. The new and published analyses are used to review compositional variation in minerals of the perrierite subgroup, which can form in a wide range of host rock compositions and over a substantial pressure- temperature range. The dominant substitutions in the various cation sites and a generalized substitution scheme are described.

Mineralogical Magazine↗

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↗

USGS2024

Energy-related rare earth element sources

Energy-related materials such as coal, coal-bearing wastes, and coal combustion products are traditionally thought of as sources or by-products of electric power generation. Increasingly, these materials are considered resources for their content of rare earth elements (REEs) and other useful constituents. In this chapter, we examine the distribution, modes of occurrence, and relative extractability of REEs from coal-derived materials. We also consider economic factors associated with recovery of REEs from these sources. While several coal-derived sources show promise for REE recovery at the pilot scale, in all cases, REE contents are much below those of primary ores, such that extraction and concentrating the REEs require new and innovative approaches that are largely developmental. Among coal-related sources, fly ash is the most REE-enriched, as REEs from coal are strongly retained in these refractory solids remaining after coal combustion. Partitioning of coal-derived elements into fly ash has been known for decades but this has yet to be commercially exploited. A key drawback shown in this chapter is that a significant fraction of REEs in fly ash is contained in highly insoluble aluminosilicate glasses that make up the largest portion of this material. In addition to testing chemical or physical pretreatment approaches to help improve the extractability of REEs from fly ash, current research is applying modern analytical approaches to better understand the distribution of REEs on increasingly smaller scales, in the interest of targeting their recovery. Next-most REE-enriched among coal-related materials are solid waste products of coal mining and wastes from coal preparation, both of which are REE-enriched relative to coal itself. These waste coals concentrate mineralogical constituents that are excluded during mining or removed during coal preparation because they do not contribute to the heating value of coal for power generation. Recovery of REEs from coal waste has shown promise at the pilot scale and has the added benefit of converting a waste into useful constituents. Total REE contents of commercial coals are, on average, much below the 300 parts per million interest level for REE recovery set by the U.S. Department of Energy (DOE). However, as reviewed in this chapter, certain horizons within coal beds show preferential REE enrichment and could be targeted by selective mining. Beyond this, certain coals are REE-enriched overall due to their unique geologic histories involving derivation from REE-enriched sediment sources, deposition of volcanic ash during coal formation, or interaction of coal with REE-bearing fluids. Acidic drainage from abandoned coal mines is produced by the breakdown of pyrite (FeS 2 ), which is unstable in oxygenated conditions. While these acidic fluids have lower REE contents than any of the coal-based solids described above, they are proportionally enriched in certain heavy rare earths, especially yttrium (Y). Precipitates from coal-based acid-mine drainage concentrate REEs to levels that are of interest for recovery, and these are also promising sources for extraction at the pilot scale.

Book chapter↗

USGS1951

Summary of the research work of the Trace Elements Section, Geochemistry and Petrology Branch, for the period January 1-March 31, 1951

This report summarized the research work of the Trace Elements Section, Geochemistry and Petrology Branch for the period January 1 - March 31, 1951. Work before that is summarized in an earlier report, "Summary of the research work of the Trace Elements Section, Geochemistry and Petrology Branch, for the period April 1, 1948 - December 31, 1950," by John C. Rabbitt (U.S. Geol. Survey Trace Elements Investigations Rept. 148, January 1951). This report will be referred to as TEIR 148. In TEIR 148 the purpose of each project was described and it is not thought necessary to repeat that material. The research work of the section consists of laboratory and related field studies in the following fields: 1. Mineralogic and petrologic investigations of radioactive rocks, minerals, and ores. 2. Investigations of chemical methods of analysis for uranium, thorium, and other elements and compounds in radioactive materials, and related chemical problems. 3. Investigations of spectographic method of analysis for a wide variety of elements in radioactive materials. 4. Investigation of radiometric methods of analysis is applied to radioactive materials. It should be emphasized that the work undertaken so far is almost entirely in the nature of investigations supporting the field appraisal of known uraniferous deposits. A program of more fundamental research, particularly in the mineralogy and geochemistry of uranium, is now being drawn up and will be submitted for approval soon. This report does not deal with the routine analytical work of the Section nor the public-sample program. The analytical work will be summarized in a report to be issued after the end of fiscal year 1951, and a report on the public-sample program is in process. Special thanks are due members of the Section who are engaged in the research work and who have supplied material for this report, the Early Ingerson, Chief of the Geochemistry and Petrology Branch for his critical review, to Jane Titcomb of the editorial staff of the Section for editing the report, and to Virginia Layne of the same staff, for typing the manuscript and the multilith mats.

Trace Elements Investigations↗

USGS2002

USGS environmental studies of the World Trade Center area, New York City, after September 11, 2001

Two days after the September 11, 2001, attack on World Trade Center (WTC), the U.S. Geological Survey (USGS) was asked by the U.S. Environmental Protection Agency (EPA) and the U.S. Public Health Service to conduct a remote sensing and mineralogical characterization study of lower Manhattan around the WTC. This study, conducted in cooperation with the National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory (JPL), was requested to rapidly provide emergency response teams with information on the concentrations and distribution of asbestos and other materials in the dusts deposited around lower Manhattan after the September 11 WTC building collapse in New York City. Preliminary results of the study were released via the internet to emergency response teams on September 18 and September 27, 2001. After September 27, additional work was done to fill remaining data gaps, and the study report underwent further detailed peer review. The report was released to the general public via the internet on November 27, 2001. This fact sheet summarizes the results of the interdisciplinary study; the full report can be viewed at http://geology.cr.usgs.gov/pub/open-file-reports/ofr-01-0429/ .

New York↗

USGS2018

Geochemistry and mineralogy of late Quaternary loess in the upper Mississippi River valley, USA: Provenance and correlation with Laurentide Ice Sheet history

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from diverse geologic terrains in North America. Further, different loess bodies that are known to have had the same source sediments (using other criteria) have similar K/Rb and K/Ba values. We also studied three thick loess sections in the upper Mississippi River valley region. At each site, the primary composition of the loess changed over the course of the last glacial period, and K/Rb and K/Ba values parallel changes in carbonate mineral content and clay mineralogy. We thus confirm conclusions of earlier investigators that loess composition changed as a result of the shifting dominance of different lobes of the Laurentide Ice Sheet and the changing course of the Mississippi River. We conclude that K/Rb and K/Ba values are effective, robust, and rapid indicators of loess provenance that can be applied to many regions of the world.

Quaternary Science Reviews↗

USGS2011

Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media

The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB and will be added to the NGDB. The AGDB data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB data provided in the linked database may be updated or changed periodically. The data on the DVD and in the data downloads provided with this report are current as of date of publication.

Data Series↗

USGS2013

Alaska Geochemical Database, Version 2.0 (AGDB2)–Including “best value” data compilations for rock, sediment, soil, mineral, and concentrate sample mediaI

The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database (AGDB, http://pubs.usgs.gov/ds/637/) before it, the AGDB2 was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This relational database, created from the Alaska Geochemical Database (AGDB) that was released in 2011, serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey personnel and analyzed in U.S. Geological Survey laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various U.S. Geological Survey programs and projects from 1962 through 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy-mineral concentrate samples are included in this database. The AGDB2 includes historical geochemical data originally archived in the U.S. Geological Survey Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the U.S. Geological Survey PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all U.S. Geological Survey geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest U.S. Geological Survey geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB2 and will be added to the NGDB. The AGDB2 data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB2 data provided in the linked database may be updated or changed periodically.

Alaska↗

USGS1954

U.S. Geological Survey Trace Elements and related reports through 1953

This report combines and brings up-to-date the information previously given in Trace Elements Investigations Report 325, "Numerical list of U.S. Geological Survey Trace Elements Reports to April 30, 1953," and Trace Elements Investigations Report 301, "Topical index and bibliography of U.S. Geological Survey Trace Elements and related reports." Part I is a numerical list of U.S. Geological Survey Trace Elements Investigations and Memorandum reports. It supersedes TEI-325. This part lists not only reports (followed by a date) that have been transmitted to the U.S. Atomic Energy Commission, but also reports in preparation (followed by an asterisk) for which tentative titles were available on December 31, 1953. Reports that have been published are indicated by the abbreviation of the medium of publication. (See also part II.) Part II is a reference guide to Trace Elements and related reports that are available to the public; this part supersedes Part 2 of the TEI-301 (published as Geological survey Circular 281). These reports are grouped according to the type of publication or release. Abstracts published in Nuclear Science Abstracts are not included in Part II, although certain TEI and TEM reports, the abstracts of which have been published in NSA, are so indicated in Part I. Publications in process on December 31, 1953, are designated by an asterisk. Part III is a finding list of states, areas, and subjects. It is based on information derived mostly from the titles of reports and, where titles are of a general nature, from a cursory review of the reports. This list is not a complete index of the information given in Trace Elements and related reports, but is designed to find subjects of major interest. Because of the numerous entries for Colorado and Utah, information has been listed by counties and, where possible, by subject under these states. Other states have county listings only if a county is included in the title of a report; otherwise, areas may be listed separately under the state. Major subjects are listed separately in the index and also where appropriate under states. Analytical methods and subjects related to analytical research are listed under Analytical Methods and Research, but not separately throughout the index. Most mineralogic studies are included under the heading Mineralogy, but are not necessarily listed according to location. Part IV is a finding list of authors. The words “with” and “and” are used to indicate seniority of authorship. For example, a listing of Jones and Brown indicates that Jones is the senior author. A listing of Jones with Brown indicates that Brown is the senior author. In both parts III and IV all Trace Elements reports are listed, as well as other related reports that have not been issued as Trace Elements reports. The following standard abbreviations have been used: TEI, Trace Elements Investigations report; TEM, Trace Elements Memorandum report; P, Professional Paper; B, Bulletin; C, Circular; J, Journal; OF, open file; TIS, Technical Information Service release; NSA, Nuclear Science Abstracts; QM, Quadrangle Map Series; and OM, Oil and Gas map or Mineral Investigations map or report.

Trace Elements Investigations↗

USGS1955

U.S. Geological Survey Trace Elements and related reports through 1954

This report supersedes TEI-400, "U.S. Geological Survey Trace Elements and related reports through 1953." Part I is a numerical list of U.S. Geological Survey Trace Elements Investigations and Memorandum reports. This part lists not only reports (followed by a date) that have been transmitted to the U.S> Atomic Energy Commission, but also reports in preparation (followed by an asterisk) for which tentative titles were available on December 31, 1954. If a report, or portion of a report, has been published, the fact is indicated by the abbreviation of the medium of publication. (See also Part II.) Part II is a reference guide to Trace Elements and related reports that are available to the public (this part supersedes Part I of Bulletin 1019-B). These reports are grouped according to the type of publication or release. If a report, or portion of the report, has been published in more than one form, appropriate cross-references are given to indicate the other forms of publication. Abstracts published in Nuclear Science Abstracts are not included in Part II; however, if the abstract of a Trace Elements report has been published in NSA, the fact is indicated in Part I. Publications in process on December 31, 1954, are designated by an asterisk. Part III is a finding list of states, areas, and subjects and supersedes Part II of Bulletin 1019-B. It is based on information derived mostly from the titles of reports and, where titles are of general nature, from a cursory review of the reports. This list is not a complete index of the information given in Trace Elements and related reports, but is designed to find subjects of major interest, Because of the numerous entries for Colorado and Utah, information has been listed by counties and, where possible, by subject under these states. Other states have county listings only if a county is included in the title of a report; otherwise, area may be listed separately under the state. Major subjects are listed separately in the index and also, where appropriate under states. Analytical methods and subjects related to analytical research are listed under Analytical Methods and Research, but not separately throughout the index. Most mineralogic studies are included under the heading Mineralogy, but are not necessarily listed according to location. Part IV is an author index. The words “with” and “and” are used to indicate seniority of authorship. For example, a listing of Smith and Brown indicated that Smith is the senior author. A listing of Smith with Brown indicates that Brown is the senior author. In both parts III and IV all Trace Elements reports are listed, as well as other related reports that have not been issued as Trace Elements reports. The following abbreviations have been used: TEI, Trace Elements Investigations report; TEM, Trace Elements Memorandum report; OF, open file; TIS, Technical Information Service release; C, Circular; B, Bulletin; P, Professional Paper; MC, Maps and Charts; J, Journal; and NSA, Nuclear Science Abstracts.

Trace Elements Investigations↗

USGS2021

Long-term African dust delivery to the eastern Atlantic Ocean from the Sahara and Sahel regions: Evidence from Quaternary paleosols on the Canary Islands, Spain

Africa is the most important source of dust in the world today and dust storms from that continent frequently deposit sediment on the nearby Canary Islands. Many investigators have inferred African dust inputs to Canary Islands paleosols based only on the presence of quartz. However, some local rocks do contain this mineral, so quartz alone is insufficient proof of dust deposition. Further, it is not known whether the Sahara Desert or the Sahel region is more important as a dust source. We address these issues by study of sequences of Pleistocene aeolian sands on the islands of Lanzarote and Fuerteventura. Aeolian sands are composed mostly of marine carbonate minerals and locally derived volcanic minerals. They date from the early-middle Pleistocene to the Holocene. Trace element geochemistry shows that the soils formed from both locally derived basalt and African dust. Major element geochemistry and clay mineralogy indicate that dust additions to the Canary Islands likely come from both the Sahara and Sahel. Dust delivered from the Sahel indicates that droughts in that region have had a history extending through much of the Quaternary. Accretionary-inflationary profile development, from dust accretion, is evident in the upward growth of Canary Islands paleosols.

Quaternary Science Reviews↗

USGS2009

The Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment

The Diviner Lunar Radiometer Experiment on NASA’s Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.

Space Science Reviews↗

USGS2026

Global pegmatite-hosted lithium, cesium, and rubidium resources: A dataset for grade and tonnage modeling

Quantitative mineral resource assessments of potential undiscovered deposits can inform future mineral supply scenarios, but their accuracy is conditional on building robust grade and tonnage models of known deposits. This study presents an up-to-date global compilation and analysis of recently discovered and original, in-situ pegmatite-hosted Li, Cs, and Rb resources prior to historic production. Our analysis yields a median tonnage of 21.2 million tons (Mt) and grade of 1.12% Li 2 O, respectively, for global Li pegmatite deposits ( n = 73). The grades and tonnages of Li pegmatite resources vary depending on the age of the bedrock host domain, pegmatite crystallization age, and primary ore mineralogy. Lithium pegmatite resources hosted in Archean to transitional Archean-Paleoproterozoic domains have the largest median tonnage (29.8 Mt; n = 38), and those hosted in Paleoproterozoic to Mesoproterozoic domains have smaller median tonnages (6.5 Mt; n = 16). Cesium deposits where pollucite is the primary ore mineral have a bimodal grade distribution, with modes of 2.40 and 0.035 wt% Cs 2 O for high- and low-grade deposits, respectively, while Rb deposits are more unimodal with a median grade of 0.247 wt% Rb 2 O. Pegmatite-hosted Cs and Rb resources have median tonnages of 7.6 and 6.3 Mt, respectively. Covariation between ore mineralogy and the degree of crustal enrichment in pegmatite-hosted deposits is diagnostic of petrogenetic differences, including melt source characteristics, magma evolution, or variable degrees of volatile solubility. The Li pegmatite compilation is suitable for fitting robust numerical models to support quantitative assessments. More well-defined Rb and Cs pegmatite resources are required for quantitative assessments, but these data provide useful information about original in-place resources for framing supply discussions.

Ore Geology Reviews↗

USGS2019

Rare earth element mineral deposits in the United States

Because of their unique special chemical properties, many of the metals in the group of rare earth elements (REEs) have essential applications in 21st century technologies. Examples of products that use REEs are cell phones, computers, fluorescent and light-emitting-diode lights, flat-screen television and computer monitors, and in high-strength magnets used by clean energy technologies such as the generators of wind turbines and batteries of hybrid and electric vehicles. REEs are used in many defense applications, such as in components of jet engines, missile guidance systems, antimissile defense systems, satellites, and communication systems. The rare earth elements have become vital to manufacturing numerous high-tech products, which has been accompanied by a large increase in their demand. At the same time, there has been concern by the United States and many other Nations about the near-monopoly of mining, processing, and supply of REEs from one Nation, China. Between 2011 and 2017, China produced approximately 84 percent of the world’s REEs, and during this time the United States only produced REEs between 2012 and 2015. The U.S. production came entirely from the Mountain Pass mine in California, providing only about 4 percent of the world REE supply. Because REEs are essential for technological applications and are primarily supplied by one Nation, there has been an increased concern in identifying new sources of REEs, including economic REE deposits. In response to these concerns, since 2009, the U.S. Geological Survey (USGS) has conducted numerous studies focused on the distribution, geology, and potential resources for the REE-bearing mineral deposits in the United States. The basic characteristics of mineral deposit types that host REE enrichments in the United Sates are summarized in this report, with selected examples. Several types of REE-enriched mineral deposits are reviewed, including deposits in carbonatites, alkaline igneous rocks, sedimentary phosphate-rich rocks (phosphorite), regions containing REE-rich veins, iron oxide deposits containing REE-bearing apatite, monazite-xenotime-bearing placer deposits (heavy-mineral sands), and ion-adsorption clay deposits (REE in granite-derived regolith). A better understanding of these mineral deposits will assist in identifying domestic resources to help alleviate the dependence on imported REEs. The economic development of REE mineral deposits is affected by many factors beyond mining, such as commodity prices and mineral processing costs. Most of the REEs are hosted by minerals that have complex chemical formulas; this presents more challenges to process and extract the REEs. Continued advancements and refinements in mineral processing techniques may allow REE deposits with complex mineralogy to be economically developed in the future.

Circular↗

USGS1969

Land subsidence due to withdrawal of fluids

Land-surface subsidence due to the withdrawal of fluids by man has become relatively common in the United States since 1940 and has been described at several other places throughout the world. This paper reviews the known examples of appreciable land subsidence caused by fluid withdrawal. Those related to exploitation of oil and gas fields include Goose Creek, Texas; Wilmington, California; Lake Maracaibo, Venezuela; Niigata, Japan; and the Po Delta in Italy. The areas of major subsidence related to ground-water withdrawal include areas in Japan; Mexico City, Mexico; and Texas, Arizona, Nevada, and California. The areas of greatest extent and maximum subsidence are in California. The principles involved in the compaction of sediments and of aquifer systems, basically the increase in effective stress, are examined briefly, together with their application to subsidence problems involving head decline both under water table and confined conditions. The amount of compaction that a confined aquifer system will experience is a function of compressibility. Other factors that influence compaction (and, in part, compressibility) include particle size and shape, clay mineralogy, geochemistry of pore water in the clayey beds and of the water in contiguous aquifers, and secondary compression. Land subsidence has caused great damage in some areas. At several of these places, subsidence problems are being alleviated in one or more of several ways; these include (1) cessation of withdrawal and (2) increase or restoration of reservoir pressure by reduction in production rate, artificial recharge, or repressuring by injection of water. The greatest subsidence control measures are being taken at Wilmington, California, where subsidence that had reached 27 feet at the center now is nearly stopped; in addition, significant rebound has occurred.

Arizona, California, Colorado, Georgia, Honshu, Ne↗