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MAJOR SOURCE OF SIDE-LOOKING AIRBORNE RADAR IMAGERY FOR RESEARCH AND EXPLORATION: THE U. S. GEOLOGICAL SURVEY.

The US Geological Survey (USGS) instituted a program in 1980 to acquire side-looking airbore radar (SLAR) data and make these data readily available to the public in a mosaic format comparable to the USGS 1:250,000-scale topographic map series. The SLAR data are also available as strip images at an acquisition scale of 1:250,000 or 1:400,000 (depending on the acquisition system), as a variety of print products and indexes, and in a limited amount in digital form on computer compatible tapes. Three different commercial X-band (3-cm) systems were used to acquire the imagery for producing the mosaics.

Conference Paper

Technical guidelines for the implementation of the Advanced National Seismic System

The Advanced National Seismic System (ANSS) is a major national initiative led by the US Geological Survey that serves the needs of the earthquake monitoring, engineering, and research communities as well as national, state, and local governments, emergency response organizations, and the general public. Legislation authorizing the ANSS was passed in 2000, and low levels of funding for planning and initial purchases of new seismic instrumentation have been appropriated beginning in FY2000. When fully operational, the ANSS will be an advanced monitoring system (modern digital seismographs and accelerographs, communications networks, data collection and processing centers, and well-trained personnel) distributed across the United States that operates with high performance standards, gathers critical technical data, and effectively provides timely and reliable earthquake products, information, and services to meet the Nation’s needs. The ANSS will automatically broadcast timely and authoritative products describing the occurrence of earthquakes, earthquake source properties, the distribution of ground shaking, and, where feasible, broadcast early warnings and alerts for the onset of strong ground shaking. Most importantly, the ANSS will provide earthquake data, derived products, and information to the public, emergency responders, officials, engineers, educators, researchers, and other ANSS partners rapidly and in forms that are useful for their needs.

Open-File Report

Trends in the occurrence of MTBE in drinking water in the Northeast United States

Public water systems in Connecticut, Maine, Maryland, New Hampshire, New Jersey, and Rhode Island sampled treated drinking water from 1993-2006 and analyzed the samples for MTBE. The US Geological Survey examined trends in the occurrence of MTBE in drinking water derived from ground water in these States for two near-decadal time steps; 1993-1999 and 2000-2006. MTBE was detected in 14% of drinking water samples collected in all States from 1993-1999 and in 19% of drinking water samples collected from the same systems from 2000-2006 and this difference was statistically significant. Trends in the occurrence of MTBE in each State by individual year indicated significant positive trends in Maryland and New Hampshire. Significant, increasing trends in MTBE concentrations were observed in Maryland and Rhode Island by individual year. This is an abstract of a paper presented at the 2007 Petroleum Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Assessment and Remediation Conference (Houston, TX 11/5-6/2007).

Conference Paper

National Center tour guide

On behalf of each employee at the Geological Survey's National Center, I [H. William Menard, Director] extend a warm welcome to you during our Centennial Year. We hope that your visit to our headquarters will be a pleasant and rewarding experience. Our scientific research is directed towards helping to solve some of the critical environmental and natural resource problems that face our Nation today. We want you to see some aspects of this work, and we hope you will visit us again. As part of the Federal Government, we are deeply committed to the concept of public service. We are proud to serve you.

Virginia

Validity of using semipermeable membrane devices for determining aqueous concentrations of freely dissolved PAHs

An in-depth review of the recent contribution to this journal by Gustafson and Dickhut [1] prompts us to share our concerns regarding some of their conclusions. The paper presents data comparing three techniques for determining aqueous concentrations of freely dissolved polycyclic aromatic hydrocarbons (PAHs) gas sparging, lipid-containing semipermeable membrane devices (SPMDs) of the U.S. Geological Survey (USGS) design, and filtration followed by sorption using XAD-2 resin. Space limitations force us to limit our comments to problems resulting from an apparent lack of understanding of how SPMDs function. Several recent publications [2–13] have described the theoretical and practical considerations of SPMD usage. Gustafson and Dickhut fail to cite any papers describing SPMDs published after 1992, even though some 18 papers have been published in American and European journals since then and several SPMD studies have been presented at many major meetings.

Environmental Toxicology and Chemistry

Geologic characteristics of sediment- and volcanic-hosted disseminated gold deposits - Search for an occurrence model

The current expansion of resource information, particularly on "disseminated" gold, and the improved technologies now available for resource investigations should place us in an enhanced position for developing a better predictive methodology for meeting one of the important responsibilities of the U.S. Geological Survey-to examine and assess the mineral resources of the geologic terranes composing the public (and privately owned) lands of the United States. The first step is systematic organization of these data. Geologic-occurrence models are an effective systematic method by which to organize large amounts of resource information into a logical sequence facilitating its use more effectively in meeting several industry and Survey objectives, which include the exploration for resources and the assessment of resource potential for land-use decisions. Such models also provide a scientific basis for metallogenesis research, which considers the observable features or attributes of ore occurrence and their "fit" into the Earth's resource puzzle. The use of models in making resource assessments/appraisals was addressed by Shawe (1981), who reported the results of a workshop on methods for resource appraisal of Wilderness and Conterminous United States Mineral Appraisal Program (CUSMAP; 1:250,000-scale quadrangles) areas. The Survey's main objective in the 1982 workshop was to evaluate the status of knowledge about disseminated or very fine grained gold deposits and, if possible, to develop an occurrence model(s). This report on the workshop proceedings has three main objectives: (1) Education through the publication of a summary review and presentation of new thinking and observations about the scientific bases for those geologic processes and environments that foster disseminated gold-ore formation; (2) systematic organization of available geologic, geochemical, and geophysical information for a range of typical disseminated gold deposits (including recognition of gaps in those data); and (3) assessment of current understanding (as presented in objective 2) toward formulating an empirical ore-occurrence model for this type of deposit. As such, this volume represents a preliminary first step at classification and provides a source of pertinent background information. Readers of this volume will soon discover, however, that full agreement has not yet been achieved in the interpretation of some of the geologic evidence. The resulting variations in tentative occurrence models for these controversial deposits ultimately will be resolved by filling the gaps in information that have already been identified. Thus, this volume does not report a U.S. Geological Survey consensus; the conclusions expressed in each chapter represent the particular interpretations of the various workshop participants.

Arizona, California, Idaho, Nevada, Utah

Internships, employment opportunities, and research grants

As an unbiased, multidisciplinary science organization, the U.S. Geological Survey (USGS) is dedicated to the timely, relevant, and impartial study of the health of our ecosystems and environment, our natural resources, the impacts of climate and land-use change, and the natural hazards that threaten us. Opportunities for undergraduate and graduate students and faculty to participate in USGS science are available in the selected programs described below. Please note: U.S. citizenship is required for all government positions. This publication has been superseded by USGS General Information Product 165 Grant Opportunities for Academic Research and Training and USGS General Information Product 166 Student and Recent Graduate Employment Opportunities . This publication is proceeded by USGS General Information Product 80 Internships, Employment Opportunities, and Research Grants published in 2008.

General Information Product

Geologic occurrences of erionite in the United States: an emerging national public health concern for respiratory disease

Erionite, a mineral series within the zeolite group, is classified as a Group 1 known respiratory carcinogen. This designation resulted from extremely high incidences of mesothelioma discovered in three small villages from the Cappadocia region of Turkey, where the disease was linked to environmental exposures to fibrous forms of erionite. Natural deposits of erionite, including fibrous forms, have been identified in the past in the western United States. Until recently, these occurrences have generally been overlooked as a potential hazard. In the last several years, concerns have emerged regarding the potential for environmental and occupational exposures to erionite in the United States, such as erionite-bearing gravels in western North Dakota mined and used to surface unpaved roads. As a result, there has been much interest in identifying locations and geologic environments across the United States where erionite occurs naturally. A 1996 U.S. Geological Survey report describing erionite occurrences in the United States has been widely cited as a compilation of all US erionite deposits; however, this compilation only focused on one of several geologic environments in which erionite can form. Also, new occurrences of erionite have been identified in recent years. Using a detailed literature survey, this paper updates and expands the erionite occurrences database, provided in a supplemental file (US_erionite.xls). Epidemiology, public health, and natural hazard studies can incorporate this information on known erionite occurrences and their characteristics. By recognizing that only specific geologic settings and formations are hosts to erionite, this knowledge can be used in developing management plans designed to protect the public.

Arizona;California;Colorado;Idaho;Montana;New Mexi

The current status of mapping karst areas and availability of public sinkhole-risk resources in karst terrains of the United States

Subsidence from sinkhole collapse is a common occurrence in areas underlain by water-soluble rocks such as carbonate and evaporite rocks, typical of karst terrain. Almost all 50 States within the United States (excluding Delaware and Rhode Island) have karst areas, with sinkhole damage highest in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. A conservative estimate of losses to all types of ground subsidence was $125 million per year in 1997. This estimate may now be low, as review of cost reports from the last 15 years indicates that the cost of karst collapses in the United States averages more than $300 million per year. Knowing when a catastrophic event will occur is not possible; however, understanding where such occurrences are likely is possible. The US Geological Survey has developed and maintains national-scale maps of karst areas and areas prone to sinkhole formation. Several States provide additional resources for their citizens; Alabama, Colorado, Florida, Indiana, Iowa, Kentucky, Minnesota, Missouri, Ohio, and Pennsylvania maintain databases of sinkholes or karst features, with Florida, Kentucky, Missouri, and Ohio providing sinkhole reporting mechanisms for the public.

Hydrogeology Journal

Archive of digital boomer seismic reflection data collected offshore east-central Florida during USGS cruise 00FGS01, July 14-22, 2000

In July of 2000, the U.S. Geological Survey (USGS), in cooperation with the Florida Geological Survey (FGS), conducted a geophysical survey of the Atlantic Ocean offshore Florida's east coast from Brevard County to northern Martin County. This report serves as an archive of unprocessed digital boomer seismic reflection data, trackline maps, navigation files, Geographic Information System (GIS) information, digital and handwritten Field Activity Collection System (FACS) logs, and Federal Geographic Data Committee (FGDC) metadata. A filtered and gained (a relative increase in signal amplitude) digital image of each seismic profile is also provided. Refer to the Acronyms page for expansions of all acronyms and abbreviations used in this report. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU) (Cohen and Stockwell, 2005). Example SU processing scripts and USGS Software for viewing the SEG-Y files (Zihlman, 1992) are also provided. The USGS St. Petersburg Coastal and Marine Science Center assigns a unique identifier to each cruise or field activity. For example, 00FGS01 tells us the data were collected in 2000 for cooperative work with the Florida Geological Survey (FGS) and the data were collected during the first field activity for that study in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the field activity ID. The boomer plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled floating on the water surface and when discharged, emits a short acoustic pulse, or shot, which propagates through the water, sediment column, or rock beneath. The acoustic energy is reflected at density boundaries (such as the seafloor, sediment, or rock layers beneath the seafloor), detected by the receiver, and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 0.5 s) and recorded for specific intervals of time (for example, 100 ms). In this way, a two-dimensional (2D) vertical profile of the shallow geologic structure beneath the ship track is produced. Figure 1 displays the acquisition geometry. Refer to table 1 for a summary of acquisition parameters. The unprocessed seismic data are stored in SEG-Y format (Barry and others, 1975). For a detailed description of the data format, refer to the SEG-Y Format page. See the How To Download SEG-Y Data page for download instructions. The printable profiles provided are GIF images that were filtered and gained using Seismic Unix software. Refer to the Software page for details about the processing and examples of the processing scripts. The printable profiles can be viewed from the Profiles page or from links located on the trackline maps. To view the trackline maps and navigation files, and for more information about these items, see the Navigation page. Detailed information about the navigation system used can be found in table 1. Of a total record length of 200 ms, only the upper 100 ms of each profile are displayed because no useful information was observed deeper in the sections. A 10 ms deep water delay appears on lines b57-b63 and sl2-sl28. No digital data were collected for line sl6. However, line sl6r is a second attempt to collect digital data for this line. Digital data and 500-shot-interval location navigation are not available for the last 1,161 shots of line sl26 due to an equipment malfunction.

Florida

Potential minability and economic viability of the Antaramut-Kurtan-Dzoragukh coal field, north-central Armenia; a prefeasibility study

The U. S. Geological Survey (USGS) conducted a coal resource assessment of several areas in Armenia from 1997 to 1999. This report, which presents a prefeasibility study of the economic and mining potential of one coal deposit found and studied by the USGS team, was prepared using all data available at the time of the study and the results of the USGS exploratory work, including core drilling, trenching, coal quality analyses, and other ongoing field work. On the basis of information currently available, it is the authors? opinion that a small surface coal mine having about a 20-year life span could be developed in the Antaramut-Kurtan-Dzoragukh coal field, specifically at the Dzoragukh site. The mining organization selected or created to establish the mine will need to conduct necessary development drilling and other work to establish the final feasibility study for the mine. The company will need to be entrepreneurial, profit oriented, and sensitive to the coal consumer; have an analytical management staff; and focus on employee training, safety, and protection of the environment. It is anticipated that any interested parties will be required to submit detailed mining plans to the appropriate Armenian Government agencies. Further development work will be required to reach a final decision regarding the economic feasibility of the mine. However, available information indicates that a small, economic surface mine can be developed at this locality. The small mine suggested is a typical surface-outcropstripping, contour mining operation. In addition, auger mining is strongly suggested, because the recovery of these low-cost mining reserves will help to ensure that the operation will be a viable, economic enterprise. (Auger mining is a system in which large-diameter boreholes are placed horizontally into the coal seam at the final highwall set as the economic limit for the surface mining operation). A special horizontal boring machine, which can be imported from Russia, is required for auger mining. Although auger-mining coal reserves do exist, the necessary development work will further verify the extent of these reserves and all of the other indicated reserves. The following items are based on the detailed study reported in this publication. Initial investment.?Following an investment of US $85,000 over a 12-month period in mine development drilling and other activities, a decision must be taken regarding further investment in an ongoing mining operation. If the new data support the opening of the surface mine, __________________________ 1Consultant, 6024 Morning Dew Drive, Austin, TX 78749. 2 U.S. Geological Survey, 956 National Center, Reston, VA 20192 1 2 MINABILITY AND ECONOMIC VIABILITY, ANTARAMUT-KURTAN-DZORAGUKH COAL FIELD the $85,000 development cost is amortized over the first 10 years of mine production. If the new data do not support the opening of the mine, the $85,000 is considered a business development expense that may be written off against profits from other operations for income or other tax purposes or simply as a business loss. Total capital required.?The equipment costs will reach a total of $900,500 which will be amortized over a 7-year period to establish estimated coal mining costs. Estimated working capital costs are $300,000, which will be borrowed. Surface mining reserves.?Approximately 840,200 metric tonnes of surface minable coal reserves at 9.3 m3 of overburden per metric tonne of minable coal is indicated. Recovery of the minable coal at 85 percent will yield 714,000 recoverable metric tonnes of marketable as-mined coal. Auger mining reserves.?Auger-mining reserves of 576,000 metric tonnes are indicated. Recoverable auger-mining reserves of 202,000 metric tonnes (at 35-percent recovery) can be expected. Auger-mining production will vary according to the hole size being used, but, in either case, augering is a very profitable addition to the mining oper

Bulletin

US Topo: Topographic Maps for the Nation

US Topo is the next generation of topographic maps from the U.S. Geological Survey (USGS). Arranged in the familiar 7.5-minute quadrangle format, digital US Topo maps are designed to look and feel (and perform) like the traditional paper topographic maps for which the USGS is so well known. In contrast to paper-based maps, US Topo maps provide modern technical advantages that support faster, wider public distribution and enable basic, on-screen geographic analysis for all users. US Topo maps are available free on the Web. Each map quadrangle is constructed in GeoPDF? format from key layers of geographic data (orthoimagery, roads, geographic names, topographic contours, and hydrographic features) found in The National Map. US Topo quadrangles can be printed from personal computers or plotters as complete, full-sized, maps or in customized sections, in a user-desired specific format. Paper copies of the maps can also be purchased from the USGS Store. Download links and a users guide are featured on the US Topo Web site. US Topo users can turn geographic data layers on and off as needed; they can zoom in and out to highlight specific features or see a broader area. File size for each digital 7.5-minute quadrangle, about 15-20 megabytes, is suitable for most users. Associated electronic tools for geographic analysis are available free for download.

Fact Sheet

US Topo: topographic maps for the nation

US Topo is the next generation of topographic maps from the U.S. Geological Survey (USGS). Arranged in the familiar 7.5-minute quadrangle format, digital US Topo maps are designed to look and feel (and perform) like the traditional paper topographic maps for which the USGS is so well known. In contrast to paper-based maps, US Topo maps provide modern technical advantages that support faster, wider public distribution and enable basic, on-screen geographic analysis for all users. The US Topo quadrangle map has been redesigned so that map elements are visually distinguishable with the imagery turned on and off, while keeping the file size as small as possible. The US Topo map redesign includes improvements to various display factors, including symbol definitions (color, line thickness, line symbology, area fills), layer order, and annotation fonts. New features for 2013 include the following: a raster shaded relief layer, military boundaries, cemeteries and post offices, and a US Topo cartographic symbols legend as an attachment. US Topo quadrangle maps are available free on the Web. Each map quadrangle is constructed in GeoPDF® format using key layers of geographic data (orthoimagery, roads, geographic names, topographic contours, and hydrographic features) from The National Map databases. US Topo quadrangle maps can be printed from personal computers or plotters as complete, full-sized, maps or in customized sections, in a user-desired specific format. Paper copies of the maps can also be purchased from the USGS Store. Download links and a users guide are featured on the US Topo Web site. US Topo users can turn geographic data layers on and off as needed; they can zoom in and out to highlight specific features or see a broader area. File size for each digital 7.5-minute quadrangle, about 30 megabytes. Associated electronic tools for geographic analysis are available free for download. The US Topo provides the Nation with a topographic product that users can quickly incorporate into decisionmaking, operational or recreational activities.

Fact Sheet

Quantifying and valuing ecosystem services: An application of ARIES to the San Pedro River basin, USA

A large body of research exists that identifies and values ecosystem services - the benefits that ecosystems provide to humans (MA, 2005) - and their underlying ecological processes. However, the development of software decision support tools that integrate ecology, economics and geography that can be independently used within the public, private, academic and NGO sectors is a more recent phenomenon (Ruhl et al., 2007; Daily et al., 2009). Spurred by growing demand for more sophisticated analysis of the social and economic consequences of land management decisions, the US Department of Interior - Bureau of Land Management (BLM) launched a pilot project with the US Geological Survey (USGS) to assess the usefulness and feasibility of ecosystem service assessment and valuation tools to provide inputs to decision-making. The project analysed ecosystem services in the US portion of the San Pedro River watershed, which includes the BLM-managed San Pedro Riparian National Conservation Area (SPRNCA), to improve the understanding of complex social and ecological relationships that transcend administrative divisions. The BLM manages some 99 million hectares, primarily in the western United States, and 283 million hectares of sub-surface mineral estate. BLM's multiple-use mission requires that it appropriately balance non-extractive uses such as habitat conservation, recreation and archaeological heritage protection and the extractive use of resources such as timber, oil and gas, coal, uranium, and other minerals.

Arizona

Assessment of surface water chloride and conductivity trends in areas of unconventional oil and gas development — Why existing national data sets cannot tell us what we would like to know

Heightened concern regarding the potential effects of unconventional oil and gas development on regional water quality has emerged, but the few studies on this topic are limited in geographic scope. Here we evaluate the potential utility of national and publicly available water-quality data sets for addressing questions regarding unconventional oil and gas development. We used existing U.S. Geological Survey and U.S. Environmental Protection Agency data sets to increase understanding of the spatial distribution of unconventional oil and gas development in the U.S. and broadly assess surface water quality trends in these areas. Based on sample size limitations, we were able to estimate trends in specific conductance (SC) and chloride (Cl − ) from 1970 to 2010 in 16% ( n = 155) of the watersheds with unconventional oil and gas resources. We assessed these trends relative to spatiotemporal distributions of hydraulically fractured wells. Results from this limited analysis suggest no consistent and widespread trends in surface water quality for SC and Cl − in areas with increasing unconventional oil and gas development and highlight limitations of existing national databases for addressing questions regarding unconventional oil and gas development and water quality.

Water Resources Research

Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle the Utah-Nevada border, with a length of about 150 miles from north to south. The general regional groundwater flow direction is from south to north towards the Great Salt Lake Desert. For 15 years with support from the Southern Nevada Water Authority (SNWA), hydrologists, geologists, and geophysicists studied the basin connections and the groundwater resources in these and adjacent flow systems over an area of about 25,000 square miles. A major first part of the SNWA study was constructing a 3-dimensional digital hydrogeologic framework based on geologic maps and cross sections at 1:250,000 scale. This framework documents the presence of three major aquifers: (1) Paleozoic carbonate rocks, (2) Eocene to Miocene volcanic rocks, and (3) Miocene to Holocene basin-fill sediments, as well as confining units that constrain flow. We interpret that movement of most groundwater through and across basins is by fracture-dominated flow along faults/fractures, yet in most places flow is prevented or retarded across faults, so mapping structures gives a first approximation to conduits and barriers to flow. The most important structures by far are high-angle normal faults of the basin-range episode of east-west extensional deformation. This event began at about 20 Ma, although most deformation and the formation of the present topography took place between 10 Ma and present. This topography consists of north-trending basins (mostly grabens) that alternate with north- trending ranges (mostly horsts); erosion of the ranges filled the basins with clastic alluvial basin-fill deposits. Geophysics provides data on the third dimension (cross sections) of the hydrogeologic framework. Audiomagnetotelluric profiles and gravity inversion located faults and enabled us to estimate thicknesses of basin-fill deposits. To this framework, hydrologic studies addressed precipitation, surface water, and springs, as well as groundwater levels, volumes, geochemistry, water budgets, and monitoring. At nearly the same time as our study, the Utah Geological Survey (UGS) and U.S. Geological Survey (USGS) addressed the same issues in many of the same areas, and publication of the efforts by all three agencies reveals a surprising similarity of conclusions, with some critical exceptions, which therefore demonstrates the great value of many scientists independently studying the same complex scientific problem. The differences in conclusions include directions and volumes of some ground- water flow paths, such as one proposed by the USGS of unlikely groundwater flow from Steptoe Valley to southern Snake Valley, and another proposed by the UGS of unlikely significant groundwater recharge flow from the Snake Range to the Fish Springs complex.

Utah

USGS Geochron Database

Introduction Geochronology helps us understand Earth’s history by determining when important events, like volcanic eruptions, the rise of mountains, the formation of mineral resources, and changes in the landscape, happened. Geochronological data directly support geologic mapping and can inform decisions about geologic hazard mitigation, natural resource management, and infrastructure resilience. The U.S. Geological Survey (USGS) Geochron database provides access to more than 300,000 published, publicly available age measurements from more than 40,000 geological samples. This database is the result of a collaborative effort with State geological surveys and geoscientists from across the globe. The USGS Geochron database is the most comprehensive collection of geochronological data available for the United States. Users can view data through an interactive map explorer, download datasets, and integrate data into geospatial software or other analysis tools.

Fact Sheet

Characterization of Lone Pine, California, tremolite asbestos and preparation of research material

Well-characterized amphibole asbestos mineral samples are required for use as analytical standards and in future research projects. Currently, the National Institute for Standards and Technology Standard Reference Material samples of asbestos are listed as ‘Discontinued’. The National Institute for Occupational Safety and Health (NIOSH) has a goal under the Asbestos Roadmap of locating and characterizing research materials for future use. Where an initial characterization analysis determines that a collected material is appropriate for use as a research material in terms of composition and asbestiform habit, sufficient amounts of the material will be collected to make it publicly available. An abandoned mine near Lone Pine, California, contains a vein of tremolite asbestos, which was the probable source of a reference material that has been available for the past 17 years from the Health and Safety Laboratory (HSL) in the UK. Newly collected fibrous vein material from this mine was analyzed at Research Triangle Institute (RTI International) with some additional analysis by the US Geological Survey’s Denver Microbeam Laboratory. The analysis at RTI International included: (i) polarized light microscopy (PLM) with a determination of principal optical properties; (ii) X-ray diffraction; (iii) transmission electron microscopy, including energy dispersive X-ray spectroscopy and selected-area electron diffraction; and (iv) spindle stage analysis using PLM to determine whether individual fibers and bundles of the samples were polycrystalline or single-crystal cleavage fragments. The overall findings of the study indicated that the material is tremolite asbestos with characteristics substantially similar to the earlier distributed HSL reference material. A larger quantity of material was prepared by sorting, acid-washing and mixing for sub-division into vials of ~10g each. These vials have been transferred from NIOSH to RTI International, from where they can be obtained on request.

California