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At least 541 records · Page 30Linked to original sources
USGS2006

U.S. Geological Survey and Bureau of Land Management Cooperative Coalbed Methane Project in the Powder River Basin, Wyoming

The Bureau of Land Management (BLM) Wyoming Reservoir Management Group and the U.S. Geological Survey (USGS) began a cooperative project in 1999 to collect technical and analytical data on coalbed methane (CBM) resources and quality of the water produced from coalbeds in the Wyoming part of the Powder River Basin. The agencies have complementary but divergent goals and these kinds of data are essential to accomplish their respective resource evaluation and management tasks. The project also addresses the general public need for information pertaining to Powder River Basin CBM resources and development. BLM needs, which relate primarily to the management of CBM resources, include improved gas content and gas in-place estimates for reservoir characterization and resource/reserve assessment, evaluation, and utilization. USGS goals include a basinwide assessment of CBM resources, an improved understanding of the nature and origin of coalbed gases and formation waters, and the development of predictive models for the assessment of CBM resources that can be used for such purposes in other basins in the United States (for example, the Bighorn, Greater Green River, and Williston Basins) and in other countries throughout the world (for example, Indonesia, New Zealand, and the Philippines). Samples of coal, produced water, and gas from coalbed methane drill holes throughout the Powder River Basin, many of which are adjacent to several active mine areas (figs. 1, 2), have been collected by personnel in the USGS, BLM Reservoir Management Group, and Casper and Buffalo BLM Field Offices. Sampling was done under confidentiality agreements with 29 participating CBM companies and operators. Analyses run on the samples include coal permeability, coal quality and chemistry, coal petrography and petrology, methane desorption and adsorption, produced-water chemistry, and gas composition and isotopes. The USGS has supplied results to the BLM Reservoir Management Group for their resource management needs, and data are released when the terms of the confidentiality agreements are completed and consent is obtained.

Fact Sheet↗
USGS1999

Lithologic, age group, magnetopolarity, and geochemical maps of the Springerville Volcanic Field, east-central Arizona

The Springerville volcanic field is one of the many late Pliocene to Holocene, mostly basaltic, volcanic fields present near the Colorado Plateau margin (fig. 1, in pamphlet). The field overlies the lithospheric transition zone between the Colorado Plateau and the Basin and Range Province (Condit and others, 1989b). Establishing relations in time, space, and composition of the rocks of these plateau-margin fields offers the possibility to integrate more fully into a regional synthesis the detailed geochemistry of these fields now being examined (for example, Perry and others, 1987; Fitton and others, 1988; Menzies and others, 1991). The work also provides baseline information for understanding mantle properties and processes at different depths and locations. Because the Springerville field is the southernmost of the plateau-margin fields, and because it contains both tholeiitic and alkalic rocks (tables 1 and 2, in pamphlet), it is a particularly important location for establishing these patterns in time, space, and composition. Our four thematic maps of the Springerville field were compiled by using digital mapping techniques so that associated petrologic and chemical data could be conveniently included in a geographic information system for one of the plateau-margin fields. Parts of these maps have been included in Condit (1995), a stand-alone Macintosh2 computer program that takes advantage of their digital format.

Arizona↗
USGS2002

Geologic map of the Frisco quadrangle, Summit County, Colorado

New 1:24,000-scale geologic mapping along the Interstate-70 urban corridor in western Colorado, in support of the USGS Central Region State/USGS Cooperative Geologic Mapping Project, is contributing to a more complete understanding of the stratigraphy, structure, tectonic evolution, and hazard potential of this rapidly developing region. The 1:24,000-scale Frisco quadrangle is near the headwaters of the Blue River and straddles features of the Blue River graben (Kellogg, K.S., 1999, Neogene basins of the northern Rio Grande rift?partitioning and asymmetry inherited from Laramide and older uplifts: Tectonophysics, v. 305, p. 141-152.), part of the northernmost reaches of the Rio Grande rift, a major late Oligocene to recent zone of extension that extends from Colorado to Mexico. The Williams Range thrust fault, the western structural margin of the Colorado Front Range, cuts the northeastern corner of the quadrangle. The oldest rocks in the quadrangle underlie the Tenmile Range and include biotite-sillimanite schist and gneiss, amphibolite, and migmatite that are intruded by granite inferred to be part of the 1,667-1,750 Ma Routt Plutonic Suite (Tweto, Ogden, 1987, Rock units of the Precambrian- basement in Colorado: U.S. Geological Survey Professional Paper 1321-A, 54 p.). The oldest sedimentary unit is the Pennsylvanian Maroon Formation, a sequence of red sandstone, conglomerate, and interbedded shale. The thickest sequence of sedimentary rocks is Cretaceous in age and includes at least 500 m of the Upper Cretaceous Pierre Shale. The sedimentary rocks are intruded by sills and dikes of dacite porphyry sills of Swan Mountain, dated at 44 Ma (Marvin, R.F., Mehnert, H.H., Naeser, C.W., and Zartman, R.E., 1989, U.S. Geological Survey radiometric ages, compilation ?C??Part five?Colorado, Montana, Utah, and Wyoming: Isochron/West, no. 53, p. 14-19. Simmons, E.C., and Hedge, C.E., 1978, Minor-element and Sr-isotope geochemistry of Tertiary stocks, Colorado mineral belt: Contributions to Mineralogy and Petrology, v. 67, p. 379-396.). Surficial deposits include (1) an old, deeply dissected landslide deposit, possibly as old as Tertiary, on the south flank of Tenderfoot Mountain, (2) deeply weathered, very coarse gravel deposits, mostly along Gold Run and underlying Mesa Cortina; the gravels are gold bearing and were mined by hydraulic methods in the 1800's, (3) glacial deposits of both Bull Lake (middle Pleistocene) and Pinedale (late Pleistocene) that were derived from large valley glaciers that flowed down Tenmile and North Tenmile Creeks; the town of Frisco is underlain mostly by Pinedale-age glacial outwash, (4) recent landslide deposits, including one large (about 1 square kilometer) area just downslope from Lilly Pad Lake, west of I-70, and (5)extensive colluvial and alluvial deposits. The latest seismic events appear to be middle Pliestocene in age and are associated with small scarps that cut Bull Lake till but do not cut Pinedale till.

Miscellaneous Field Studies Map↗
USGS2002

Analysis of magnetotelluric profile data from the Ruby Mountains metamorphic core complex and southern Carlin Trend region, Nevada

We have collected about 150 magnetotelluric (MT) soundings in northeastern Nevada in the region of the Ruby Mountains metamorphic core complex uplift and southern Carlin mineral trend, in an effort to illuminate controls on core complex evolution and deposition of world-class gold deposits. The region has experienced a broad range of tectonic events including several periods of compressional and extensional deformation, which have contributed to the total expression of electrical resistivity. Most of the soundings are in three east-west profiles across increasing degrees of core uplift to the north (Bald Mountain, Harrison Pass and Secret Pass latitudes). Two shorter lines cross a prominent east-west structure to the north of the northern profile. MT impedance tensor and vertical magnetic field rotations imply a N-NNE average regional geoelectric strike, similar to surface geologic trends. Model resistivity cross sections were derived using a 2-D inversion algorithm, which damps departures of model parameters from an a priori structure, emphasizing the transverse magnetic (TM) mode and vertical magnetic field data. Geological interpretation of the resistivity combines previous seismic, potential field and isotope models, structural and petrological models for regional compression and extension, and detailed structural/stratigraphic interpretations incorporating drilling for petroleum and mineral exploration. To first order, the resistivity structure is one of a moderately conductive, Phanerozoic sedimentary section fundamentally disrupted by intrusion and uplift of resistive crystalline rocks. Late Devonian and early Mississippian shales of the Pilot and Chainman Formations together form an important conductive marker sequence in the stratigraphy and show pronounced increases in conductance (conductivity-thickness product) from east to west. These increases in conductance are attributed to graphitization caused by Elko-Sevier era compressional shear deformation and possibly by intrusive heating. The resistive crystalline central massifs adjoin the host stratigraphy across crustal-scale, subvertical fault zones. These zones provide electric current pathways to the lower crust for heterogeneous, upper crustal induced current flow. Resistive core complex crust may be steeply bounded under the middle of the neighboring grabens and not deepen at a shallow angle to arbitrary distances to the west. The numerous crustal breaks imaged with MT may contribute to the low effective elastic thickness estimated regionally for the Great Basin and exemplify the mid-crustal, steeply dipping slip zones in which major earthquakes nucleate. An east-west oriented conductor in the crystalline upper crust spans the East Humboldt Range and northern Ruby Mountains. The conductor may be related to an inferred ArcheanProterozoic suture or nearby graphitic metasediments, with possible alteration by middle Tertiary magmatic activity. Lower crustal resistivity everywhere under the profiles is low and appears quasi one-dimensional. It is consistent with a low rock porosity (

Open-File Report↗
USGS2003

Correlation of the Klamath Mountains and Sierra Nevada

This report graphically portrays the broadly parallel tectonic development of the Klamath Mountains and Sierra Nevada from early Paleozoic to Early Cretaceous time. It is dedicated to J.S. Diller of the U.S. Geological Survey who, during his pioneer field studies a century ago, recognized significant similarities between these two important provinces. The report is based mainly on the numerous published reports of the field and laboratory studies by various geologists and students during the last century, and to a lesser extent on my own field work which has been substantial in the Klamath Mountains but minimal in the Sierra Nevada. For brevity, required by the format of this report, little of the extensive literature pertaining to these two provinces is referenced. This report is preliminary in nature and was prepared as an aid to further study of the tectonic relations between the Klamath Mountains and Sierra Nevada. This report consists of two sheets: Sheet 1, Map showing accreted terranes and plutons of the Klamath Mountains and Sierra Nevada, and Sheet 2, Successive accretionary episodes of the Klamath mountains and northern part of Sierra Nevada, showing related plutonic, volcanic, and metamorphic events. The map on Sheet 1 was compiled and modified from two Open-File maps (Irwin and Wooden, 1999 and 2001) which had been compiled and modified mainly from Jennings (1977), Harwood (1992), Irwin (1994), Jayko (1988), Graymer and Jones (1994), Edelman and Sharp (1989), Schweickert and others (1999), Saucedo and Wagner(1992), Saleeby and Sharp (1980), Wagner and others (1981), and various other sources. For detailed lists of the sources for the isotopic age data used in Sheets 1 and 2, see Irwin and Wooden (1999 and 2001). On Sheet 2, the accretionary episodes are shown sequentially from left to right in two tiers of figures. Episodes for the Klamath Mountains are in the upper tier; correlative episodes of the Sierra Nevada are directly below in the lower tier. The sequence shown for the Klamath Mountains is modified from Irwin and Mankinen (1998) and Irwin and Wooden (1999). The episodes are named for the accreting terranes of the Klamath Mountains, but those names may not be suitable for reference to the correlative episodes of the Sierra Nevada. In the figure for each episode, a heavy black line represents the active suture that separated oceanic crustal rocks on the left from the earlier accreted terranes on the right. Plutons are particularly useful for timing the accretionary episodes. The preaccretionary plutons, which commonly represent the roots of oceanic volcanic arcs, are shown in the accreting oceanic crustal rocks to the left of the heavy black line. The accretionary plutons consist of rock that has been subducted and remobilized as magma during the accretionary process and injected into an overlying earlier accreted terrane on the right of the heavy black line. Thus, isotopic dating of the accretionary plutons (preferably U/Pb dates measured on zircon extracted from the plutonic rock) provides a useful basis for assigning ages to the accretionary episodes. Many plutons are rootless at depth, as they tend to be truncated by the subduction zone sutures of younger accreting terranes. Volcanic deposits resulting from accretionary episodes apparently are uncommon except for those deposited on the backstop terranes. In the Klamath Mountains, the Eastern Klamath terrane, which consists of the Yreka, Trinity and Redding subterranes, was the backstop for the Central Metamorphic and younger accretionary episodes, and displays a remarkable record of sedimentation, volcanism and plutonism from Silurian-Devonian to Jurassic time. In the Sierra Nevada, the correlative backstop was the Northern Sierra terrane which shows a similar long record of volcanism in the Taylorsville, Permian, and Jurassic volcanic arc sequences. During some accretionary episodes the subducting oceanic rocks were dynamically metamorphosed to schist along the suture zone beneath the overriding accreted terranes. Examples of this in the Klamath Mountains are the Devonian Salmon and Abrams Schists of the Central Metamorphic terrane, the Triassic(?) schist of the Fort Jones terrane , and the Early Cretaceous South Fork Mountain Schist that structurally underlies Klamath Mountains terranes along much of the western edge of the province. The Fort Jones terrane and South Fork Mountains Schist were metamorphosed under blueschist-facies conditions. In the Sierra Nevada, schist that is correlative with the Central Metamorphic terrane is present in patches along the Feather River terrane (see Hacker and Peacock, 1990); the Triassic(?) Red Ant Schist is correlative with the Fort Jones terrane; but a correlative of the South Fork Mountain Schist is not present. In addition to the similarities in the sequences of accretion, plutonism, volcanism, and metamorphism, strong ties between the two provinces are also provided by paleontologic data. The Permian McCloud fusulinid fauna of the Redding subterrane also is present in the Northern Sierra terrane. Rare Tethyan fusulinids are found in Permian limestone of the Eastern Hayfork terrane of the Klamath Mountains and also in limestone blocks in the Central Belt of the Sierra Nevada. Ichthyosaur fossils have been collected from the Triassic of both the Redding subterrane and Northern Sierra terrane. Jurassic ammonites and the pelecypod Buchia concentrica occur in both the Galice Formation of the western Klamath Mountains and the Mariposa Formation of the western Sierra Nevada. Events that preceded the Central Metamorphic episode prior to Silurian-Devonian time are not clearly understood and are not shown in the succession of diagrams on Sheet 2. The oldest rocks of the Klamath Mountains are Neoproterozic and they predate the Central Metamorphic episode by possibly a hundred million years or more. They include ophiolitic rocks of the Trinity subterrane and the Antelope Mountain Quartzite of the Yreka subterrane (see Mankinen and others, 2002). In the Sierra Nevada, correlatives of the ancient ophiolitic rocks may be part of the Feather River terrane. Although Neoproterozoic fossils have not yet been found in the Sierra Nevada, petrologic study shows the quartzite of the Lang sequence is closely similar to the Antelope Mountain Quartzite (see Bond and Devay, 1980). Correlation of the two quartzite formations is also suggested by the similarity of their positions in the accretionary sequence.

Klamath Mountains, Sierra Nevada↗
USGS2003

A compilation of whole-rock and glass major-element geochemistry of Kilauea Volcano, Hawai'i, near-vent eruptive products: January 1983 through September 2001

This report presents major-element geochemical data from 652 glasses (~6,520 analyses) and 795 whole-rock aliquots from 1,002 fresh samples of olivine-tholeiitic lava collected throughout the near-continuous eruption of Kïlauea Volcano, Hawai'i, from January 1983 through September 2001. The data presented herein provide a unique temporal compilation of lava geochemistry that best reflects variations of pre-eruptive magma compositions during prolonged rift-zone eruption. This document serves as a repository for geochemical data referred to in U.S. Geological Survey Professional Paper 1676 (Heliker, Swanson, and Takahashi, eds., 2003) which includes multidisciplinary research papers pertaining to the first twenty years of Puu Oo-Kupaianaha eruption activity. Details of eruption characteristics and nomenclature are provided in the introductory chapter of that volume (Heliker and Mattox, 2003). Geochemical relations among all or portions of this data set are depicted and interpreted by Thornber (2003), Thornber and others (2003) and Thornber (2001). Trace element compositions and Nd, Sr and Pb isotopic analyses of representative samples of this select eruption suite will be provided in a separate and complimentary open file report. From 1983 to October 2001, approximately 2,500 eruption samples were collected and archived by the U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO). Geochemical data for 1,002 of these samples are included here. Previous reports present bulk-lava major- element chemistry for eruption samples collected from 1983 to 1986 and from 1990 to 1994 (Neal and others, 1988 and Mangan and others, 1995, respectively). Major element glass chemistry and thermometry data for samples collected from 1983 to 1994 is reported by Helz and Hearn (1998) and whole-rock and glass chemistry for samples collected from September 1994 to October 2001 is provided by Thornber and others (2002). This report is a compilation of previously published data along with unpublished whole-rock data for the 1986–1990 eruptive interval (episode 48, see Heliker and Mattox, 2003). The geochemical data in this report is mostly limited to well-quenched samples collected at or near their respective vents. The samples include tephra and spatter, in addition to lava dipped from lava lakes, lava tubes, and surface lava flows. The details of sample collection techniques as described by Thornber and others (2002) are generally applicable for this entire sampling interval. Specifically excluded from this database are samples of distal surface flows, many of which were collected for topical studies of emplacement dynamics (for example, Cashman and others, 1999). Samples of sluggish or crystal-laden tube flows collected during eruptive pauses were also excluded, because they bear visual, petrographic and geochemical evidence for crystal accumulation during surface-flow stagnation. In addition, the pre-1992 whole-rock major element data reported here has been corrected to compensate for minor analytical discrepancies between pre- and post-1991 XRF analyses. These discrepancies resulted from a change in instrumentation at the USGS Denver analytical laboratories. This select suite of time-constrained geochemical data is suitable for constructing petrologic models of pre-eruptive magmatic processes associated with prolong rift zone eruption of Hawaiian shield volcanoes.

Hawai'i↗
USGS2006

Review of lignite resources of western Tennessee and the Jackson Purchase area, western Kentucky

Introduction: This review of the lignite deposits of western Tennessee and the Jackson Purchase area in western Kentucky (Fig. 1) is a preliminary report on part of the U.S. Geological Survey's National Coal Resource Assessment of the Gulf Coastal Plain Coal Province. Lignite deposits of western Kentucky and Tennessee are an extension of the Gulf Coastal Plain Coal Province (Cushing and others, 1964), and currently are not economic to mine. These deposits have not been extensively investigated or developed as an energy resource. This review includes a description of the geology of the lignite-bearing units, a discussion of the available coal quality data, and information on organic petrology. Palynological data for lignite samples collected in Kentucky and Tennessee as part of this work are presented in an Appendix.

Open-File Report↗
USGS2007

Great Basin Paleontological Bibliography

Introduction This work was conceived as a derivative product for 'The Metallogeny of the Great Basin' project of the Mineral Resources Program of the U.S. Geological Survey. In the course of preparing a fossil database for the Great Basin that could be accessed from the Internet, it was determined that a comprehensive paleontological bibliography must first be compiled, something that had not previously been done. This bibliography includes published papers and abstracts as well as unpublished theses and dissertations on fossils and stratigraphy in Nevada and adjoining portions of California and Utah. This bibliography is broken into first-order headings by geologic age, secondary headings by taxonomic group, followed by ancillary topics of interest to both paleontologists and stratigraphers; paleoecology, stratigraphy, sedimentary petrology, paleogeography, tectonics, and petroleum potential. References were derived from usage of Georef, consultation with numerous paleontologists and geologists working in the Great Basin, and literature currently on hand with the authors. As this is a Web-accessible bibliography, we hope to periodically update it with new citations or older references that we have missed during this compilation. Hence, the authors would be grateful to receive notice of any new or old papers that the readers think should be added. As a final note, we gratefully acknowledge the helpful reviews provided by A. Elizabeth J. Crafford (Anchorage, Alaska) and William R. Page (USGS, Denver, Colorado).

Open-File Report↗
USGS2007

Tectonics of the West Antarctic rift system: new light on the history and dynamics of distributed intracontinental extension

The West Antarctic rift system (WARS) is the product of multiple stages of intracontinental deformation from Jurassic to Present. The Cretaceous rifting phase accomplished >100 percent extension across the Ross Sea and central West Antarctica, and is widely perceived as a product of pure shear extension orthogonal to the Transantarctic Mountains that led to breakup and opening of the Southern Ocean between West Antarctica and New Zealand. New structural, petrological, and geochronological data from Marie Byrd Land reveal aspects of the kinematics, thermal history, and chronology of the Cretaceous intracontinental extension phase that cannot be readily explained by a single progressive event. Elevated temperatures in "Lachlan-type" crust caused extensive crustal melting and mid-crustal flow within a dextral transcurrent strain environment, leading to rapid extension and locally to exhumation and rapid cooling of a migmatite dome and detachment footwall structures. Peak metamorphism and onset of crustal flow that brought about WARS extension between 105 Ma and 90 Ma is kinematically, temporally, and spatially linked to the active convergent margin system of East Gondwana. West Antarctica-New Zealand breakup is distinguished as a separate event at 83-70 Ma, from the standpoint of kinematics and thermal evolution

Open-File Report↗
USGS2007

Fly Ash: From Cradle to Grave

The Energy Resources Program of the U.S. Geological Survey promotes and supports coal research to improve the understanding of the coal endowment of the United States. This results in geologically based, non-biased energy information products for policy and decision makers, land and resource managers, other federal and state agencies, the domestic energy industry, foreign governments, nongovernmental groups, academia, and other scientists. A more integrated approach to our coal quality work involves what we call a 'cradle to grave' approach. These types of studies focus not on just one aspect of the coal but rather on how or where different quality parameters form and (or) occur and what happens to them through the mining, production, transport, utilization and waste disposal process. An extensive suite of coal quality analyses, mineralogical, petrology, and leaching investigations are determined on samples taken from the different phases of the coal utilization process. This report consists of a tutorial that was given on June 10, 2007 at the 32nd International Technical Conference on Coal Utilization & Fuel Systems, The Power of Coal, Clearwater Coal Conference in Clearwater, Florida, USA. This tutorial covers how these studies are conducted and the importance of providing improved, comprehensive, science-based data sets for policy and decision makers.

Open-File Report↗
USGS2008

Geochemistry of Rock Samples Collected from the Iron Hill Carbonatite Complex, Gunnison County, Colorado

A study conducted in 2006 by the U.S. Geological Survey collected 57 surface rock samples from nine types of intrusive rock in the Iron Hill carbonatite complex. This intrusive complex, located in Gunnison County of southwestern Colorado, is known for its classic carbonatite-alkaline igneous geology and petrology. The Iron Hill complex is also noteworthy for its diverse mineral resources, including enrichments in titanium, rare earth elements, thorium, niobium (columbium), and vanadium. This study was performed to reexamine the chemistry and metallic content of the major rock units of the Iron Hill complex by using modern analytical techniques, while providing a broader suite of elements than the earlier published studies. The report contains the geochemical analyses of the samples in tabular and digital spreadsheet format, providing the analytical results for 55 major and trace elements.

Open-File Report↗
USGS2008

Catalog of Mount St. Helens 2004-2007 dome samples with major- and trace-element chemistry

Sampling and analysis of eruptive products at Mount St. Helens is an integral part of volcano monitoring efforts conducted by the U.S. Geological Survey?s Cascades Volcano Observatory (CVO). The objective of our eruption sampling program is to enable petrological assessments of pre-eruptive magmatic conditions, critical for ascertaining mechanisms for eruption triggering and forecasting potential changes in eruption behavior. This report provides a catalog of near-vent lithic debris and new dome-lava collected during 34 intra-crater sampling forays throughout the October 2004 to October 2007 (2004-7) eruptive interval at Mount St. Helens. In addition, we present comprehensive bulk-rock geochemistry for a time-series of representative (2004-7) eruption products. This data, along with that in a companion report on Mount St. Helens 2004 to 2006 tephra by Rowe and others (2008), are presented in support of the contents of the U.S. Geological Survey Professional Paper 1750 (Sherrod and others, eds., 2008). Readers are referred to appropriate chapters in USGS Professional Paper 1750 for detailed narratives of eruptive activity during this time period and for interpretations of sample characteristics and geochemical data. The suite of rock samples related to the 2004-7 eruption of Mount St. Helens and presented in this catalog are archived at the David A. Johnson Cascades Volcano Observatory, Vancouver, Wash. The Mount St. Helens 2004-7 Dome Sample Catalogue with major- and trace-element geochemistry is tabulated in 3 worksheets of the accompanying Microsoft Excel file, of2008-1130.xls. Table 1 provides location and sampling information. Table 2 presents sample descriptions. In table 3, bulk-rock major and trace-element geochemistry is listed for 44 eruption-related samples with intra-laboratory replicate analyses of 19 dacite lava samples. A brief overview of the collection methods and lithology of dome samples is given below as an aid to deciphering the dome sample catalog. This is followed by an explanation of the categories of sample information (column headers) in Tables 1 and 2. A summary of the analytical methods used to obtain the geochemical data in this report introduces the presentation of major- and trace-element geochemistry of 2004-7 Mount St. Helens dome samples in table 3. Intra-laboratory results for the USGS AGV-2 standard are presented (tables 4 and 5), which demonstrate the compatibility of chemical data from different sources.

Open-File Report↗
USGS2009

Catalog of Tephra samples from Kilauea's summit eruption, March-December 2008

The opening of a new vent within Halema'uma'u Crater in March 2008 ended a 26-year period of no eruptive activity at the summit of Kilauea Volcano. It also heralded the first explosive activity at Kilauea's summit since 1924 and the first of eight discrete explosive events in 2008. At the onset of the eruption, the Hawaiian Volcano Observatory (HVO) initiated a rigorous program of sample collection to provide a temporally constrained suite of tephra samples for petrographic, geochemical, and isotopic studies. Petrologic studies help us understand conditions of magma generation at depth; processes related to transport, storage, and mixing of magma within the shallow summit region; and specific circumstances leading to explosive eruptions. This report provides a catalog of tephra samples erupted at Kilauea's summit from March 19, 2008, through the end of 2008. The Kilauea 2008 Summit Sample Catalog is tabulated in the accompanying Microsoft Excel file, of2009-1134.xls (four file types linked on right). The worksheet in this file provides sampling information and sample descriptions. Contextual information for this catalog is provided below and includes (1) a narrative of 2008 summit eruptive activity, (2) a description of sample collection methods, (3) a scheme for characterizing a diverse range in tephra lithology, and (4) an explanation of each category of sample information (column headers) in the Microsoft Excel worksheet.

Hawaii↗
USGS2009

Low-fluorine Stockwork Molybdenite Deposits

Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (<2 to >10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

Open-File Report↗
USGS2010

Buddingtonite in Menlo Park, California

The mineral buddingtonite, named after A.F. Buddington, long-time professor of petrology at Princeton University, was first identified at the Sulfur Bank mine in Lake County, California (Erd and others, 1964). The ammonium feldspar was recognized in Menlo Park, California, in 1964 by the author, with Erd's help, shortly before publication of the original description of the new mineral. Subsequently, buddingtonite has been widely recognized in hydrothermal mineral deposits and has been used in remote-sensing applications by the mineral industry. Buddingtonite also has been identified in the Phosphoria Formation and in oil shales of the Green River Formation. This paper briefly describes the geologic setting and mineralogy of the occurrences of buddingtonite and other ammonium-bearing minerals in the vicinity of Menlo Park.

Open-File Report↗
USGS2010

Whole-rock analyses of core samples from the 1988 drilling of Kilauea Iki lava lake, Hawaii

This report presents and evaluates 64 major-element analyses of previously unanalyzed Kilauea Iki drill core, plus three samples from the 1959 and 1960 eruptions of Kilauea, obtained by X-ray fluorescence (XRF) analysis during the period 1992 to 1995. All earlier major-element analyses of Kilauea Iki core, obtained by classical (gravimetric) analysis, were reported and evaluated in Helz and others (1994). In order to assess how well the newer data compare with this earlier suite of analyses, a subset of 24 samples, which had been analyzed by classical analysis, was reanalyzed using the XRF technique; those results are presented and evaluated in this report also. The XRF analyses have not been published previously. This report also provides an overview of how the chemical variations observed in these new data fit in with the chemical zonation patterns and petrologic processes inferred in earlier studies of Kilauea Iki.

Kilauea Iki Lava Lake↗
USGS2014

A reconnaissance for signs of a Mississippi Valley-type lead-zinc mineralizing system on the eastern flank of the Rutbah Uplift, Anbar Province, Iraq

Reconnaissance field visits and rock sampling were conducted at eight geologically selected locations within Mesozoic rocks on the eastern flank of the Rutbah Uplift, Anbar Province, western Iraq, in an attempt to determine if these rocks have been affected by a Mississippi Valley-Type (MVT) lead-zinc mineralizing system. Samples subsequently were studied by carbonate mineral staining, transmitted and reflected light petrology, and scanning electron microscopy with semi-quantitative energy dispersive elemental analyses. Single samples were studied by each, inductively coupled plasma mass spectrometry analyses of trace elements and fluid inclusion microthermometry. Permissive evidence indicates that there has been a MVT system present, but none of the evidence is considered definitive.

Anbar Province↗
USGS2016

Geologic and geochemical results from boreholes drilled in Yellowstone National Park, Wyoming, 2007 and 2008

Between 2007 and 2008, seven Earthscope Plate Boundary Observatory (PBO) boreholes ranging in depth from about 200 to 800 feet deep were drilled in and adjacent to the Yellowstone caldera in Yellowstone National Park, for the purpose of installing volcano monitoring instrumentation. Five of the seven boreholes were equipped with strainmeters, downhole seismometers, and tiltmeters. Data collected during drilling included field observations of drill cuttings, stratigraphy within the boreholes, water temperature, and water and drill cuttings samples from selected depths. Six of the seven boreholes encountered rhyolite lavas and tuffs. The rhyolite lavas compose the Canyon flow, the Gardner River flow, the Gibbon River flow, the Hayden Valley flow, the Nez Perce Creek flow, and the West Thumb flow. Boreholes also penetrated a vertical sequence through the Lava Creek Tuff and the Tuff of Bluff Point. In addition, one borehole drilled through a Swan Lake Flat Basalt sequence and terminated in a rhyolite lava flow. After drilling the seven PBO boreholes, cuttings were examined and selected for preparation of grain mounts, thin sections, and geochemical analysis. Major ions and trace elements (including rare earth elements) of selected cuttings were determined by x-ray fluorescence (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS); the ICP-MS provided more precise trace-element analysis than XRF. A preliminary interpretation of the results of geochemical analyses generally shows a correlation between borehole cuttings and previously mapped geology. The geochemical data and borehole stratigraphy presented in this report provide a foundation for future petrologic, geochemical, and geophysical studies.

Wyoming↗