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At least 451 records · Page 25Linked to original sources
USGS2008

Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005

U.S. Geological Survey (USGS) historically has not attempted to report comprehensive world production of gemstones on a country basis. This was because estimation of gemstone production is inherently difficult due to the fragmentary nature of the industry, the lack of governmental oversight or reporting in many countries where colored gemstones are mined, and the wide variation in quality between individual gemstones. Unlike diamonds, which, with the exception of the alluvial stones of West Africa, are mainly produced by large international mining companies and evaluated, cut, and marketed through a highly developed pricing structure and complex commercial arrangements, colored gemstones are mainly mined by individuals or small companies and have less developed evaluation and marketing arrangements. The trading centers for colored gems are smaller and less well known than the diamond centers. Colored gemstones, like alluvial diamonds, have the potential to be used to fund civil conflicts and other illegal activities, and because trade in colored gemstones is less organized than that of diamonds, they offer less opportunity for effective regulation of their trade. And, like diamond, until the recent advent of the Kimberley Process no generally accepted estimates of colored gemstone production globally or by producing country have existed. The present paper is a first attempt to develop production statistics for the three precious gems - emeralds , rubies , and sapphires - and tanzanite tanzanite, a semi-precious gem. The data consist of the weight of production of each of the gemstones from 1995 through 2005. Preliminary data on the weights of gemstone production were presented as a poster session at the Gemological Institute of America's Gemological Research Conference in San Diego, CA, in 2006, and as a published abstract (Yager, 2006) in an attempt to gather response to the estimates. The USGS continues to welcome information and suggestions that would improve the data presented here. Information used to make the production estimates presented in this paper include annual USGS Mineral Questionnaires completed by producing countries, data on exports from producing countries, reports from the literature, and company reports. Comparisons of the weight and the value of production of a type of gemstone between countries may differ considerably. Whereas east African countries dominate the weight production of rubies, Burma (Myanmar) is widely thought to have the highest value of ruby production. Data on the value of gemstone production are even more difficult to estimate than is the weight of production. Value of production is dependent upon both the quality and the sizes of the stones produced. Such data are not readily available and are difficult to estimate; therefore this report does not present tables of values of production. Instead, the report briefly discusses the forms in which gemstones are sold, the systems used to value the gemstones, and selected data that illustrate the variability of value of gemstones of a particular type.

Open-File Report↗
USGS2012

Magnetic map of the Irish Hills and surrounding areas, San Luis Obispo County, central California

A magnetic map of the Irish Hills and surrounding areas was created as part of a cooperative research and development agreement with the Pacific Gas and Electric Company and is intended to promote further understanding of the areal geology and structure by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on magnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can be related to either lithologic or structural boundaries. Magnetic susceptibility measurements from the area indicate that bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because some sedimentary units also can produce measurable magnetic anomalies. Remanent magnetization does not appear to be a significant source for magnetic anomalies because it is an order of magnitude less than the induced magnetization. The map is a mosaic of three separate surveys collected by (1) fixed-wing aircraft at a nominal height of 305 m, (2) by boat with the sensor at sea level, and (3) by helicopter. The helicopter survey was flown by New-Sense Geophysics in October 2009 along flight lines spaced 150-m apart and at a nominal terrain clearance of 50 to 100 m. Tie lines were flown 1,500-m apart. Data were adjusted for lag error and diurnal field variations. Further processing included microleveling using the tie lines and subtraction of the reference field defined by International Geomagnetic Reference Field (IGRF) 2005 extrapolated to August 1, 2008.

California↗
USGS1985

Procedural guide for International Gauging Stations on boundary waters between Canada and the United States of America

Since 1909, the United States of America (U.S.A.) and Canada have employed a system of monitoring stream-flow and water levels for shared waters based upon professionalism, trust and goodwill. This document has been prepared in considerable detail for use by managers and field officers at all levels of government in Canada and the United States. Its purpose is to serve as a guide in attaining uniform procedures in the designation and operation of International Gauging Stations. For special situations where these procedures do not apply, specific mention is made in appropriate sections of the guide. This guide supersedes that of November 4, 1969, and the guide entitled "The Procedural Guide for Operation of International Gauging Stations, St. Mary-Milk Rivers," dated March 12, 1979.

Open-File Report↗
USGS1994

Sediment-quality assessment of Franklin D. Roosevelt Lake and the upstream reach of the Columbia River, Washington, 1992

The occurrence and distribution of trace elements and of wood-pulp-related compounds in the sediments of Lake Roosevelt and the upstream reach sampler of the Columbia River were studied in 1992. In addition, an analysis of benthic invertebrate community structure and tests of sediment toxicity were conducted. Concentrations of trace elements were elevated, relative to background reference sites, in samples of bed sediment. Copper, lead, and zinc most often exceeded the sediment-quality guidelines for benthic organisms. In whole-water samples, trace-element concentrations did not exceed criteria for freshwater organisms. These concentrations were relatively small, reflecting the small suspended-sediment concentrations and the large water-diluting capacity of the Columbia River. Elevated concentrations of trace elements in sediments are attributable to the transport of metallurgical waste from a smelter discharging to the Columbia River in Canada. Dioxins and furans were found in Columbia River water, but only a few isomers were detected. A furan isomer common in effluent from pulp and paper mills was found in suspended sediment. Dioxins and furans in the water phase were isolated using solid-phase extraction to concentrate these compounds from large volumes of water. Few of the many other organic compounds associated with wood-pulp waste were detected in the bed sediments of Lake Roosevelt. Benthic invertebrate communities in the Columbia River showed effects from trace elements in bed sediments or from loss of physical habitat. Lethal and sublethal effects were observed in toxicity tests of selected aquatic organisms exposed to bed sediments from the Columbia River near the international boundary.

Washington↗
USGS2022

Light attenuation and erosion characteristics of fine sediments in a highly turbid, shallow, Great Basin Lake—Malheur Lake, Oregon, 2017–18

Malheur Lake is a large, shallow, turbid lake in southeastern Oregon that fluctuates widely in surface area in response to yearly precipitation and climatic cycles. High suspended-sediment concentrations (SSCs) likely are negatively affecting the survival of aquatic plants by reducing the intensity of solar radiation reaching the plants, thus inhibiting photosynthesis. This study was designed to determine the types of suspended material, the erodibility of the lakebed, the attenuation of photosynthetically active radiation (PAR) through the water column, and the effects of wind and precipitation on SSC. Two sites in the lake were monitored for approximately 5 months during the summer growing season each year (2017–19). At these sites, turbidity, chlorophyll a fluorescence (a surrogate for concentration), and underwater PAR measurements were collected continuously, and discrete samples were collected every 2 weeks and analyzed for SSC, loss on ignition, and chlorophyll a concentration. Underwater PAR profile measurements were collected during site visits, and a nearby meteorological station recorded terrestrial PAR and wind speeds. About 18 percent of suspended material in the water was organic and mostly detrital. Nearly 100 percent of all suspended material was fine material (less than 63 micrometers), and more than 90 percent of the surficial lakebed material was fine material. The high concentrations of fine material in the water column can be expected to strongly attenuate light. SSC was significantly higher at both sites in 2018 compared to 2017 and 2019; the interannual differences were mostly due to the lower amount of precipitation in 2018, which resulted in shallower lake depths. Three years of SSC values multiplied by water depth showed a seasonal pattern: concentrations were often highest in early spring, lowest in summer, and intermediate in autumn. Episodic wind events with speeds of 5–10 meters per second caused rapid increases in turbidity above background that lasted for a few days. However, a baseline SSC value multiplied by water depth (estimated to be 0.11 kilograms per square meter) was present between wind events and even under ice, suggesting a persistent suspension of very fine, highly erodible material. Terrestrial and underwater PAR measurements were used to develop a relation between PAR attenuation and turbidity that can be used in modeling restoration scenarios. Calculated bottom shear stress caused by wind-generated waves ranged from 0 to 0.4 pascals (Pa). Erosion experiments indicated variability in the bottom sediments from the two lake sites, but much of the lakebed is highly erodible at a threshold of 0.05 to 0.1 Pa. Restoration actions may target the persistent turbidity (for example, the use of flocculation) or transient turbidity (for example, construction of wave-reduction barriers), with a goal of attaining approximately 36 micromoles photons per square meter per second of PAR at the lakebed to promote emergence of sago pondweed and other desirable plants. Currently, that threshold often is reached from 4 to 34 centimeters (cm) below the water surface in 1 meter water depth, depending on wind conditions, but halving persistent turbidity would increase the upper end of the range to 55 cm. Additional studies regarding the effects of (1) sediment drying on resuspension and (2) nutrient inputs and internal cycling on phytoplankton populations would help determine the most appropriate restoration strategies.

Oregon↗
USGS2013

Metallogenic belt and mineral deposit maps of northeast Asia

This report contains explanatory material and summary tables for lode mineral deposits and placer districts (Map A, sheet 1) and metallogenic belts of Northeast Asia (Maps B, C, and D on sheets 2, 3, and 4, respectively). The map region includes eastern Siberia, southeastern Russia, Mongolia, northeast China, and Japan. A large group of geologists—members of the joint international project, Major Mineral Deposits, Metallogenesis, and Tectonics of Northeast Asia—prepared the maps, tables, and introductory text. This is a cooperative project with the Russian Academy of Sciences, Mongolian Academy of Sciences, Mongolian National University, Ulaanbaatar, Mongolian Technical University, Mineral Resources Authority of Mongolia, Geological Research Institute, Jilin University, China Geological Survey, Korea Institute of Geoscience and Mineral Resources, Geological Survey of Japan, and U.S. Geological Survey. This report is one of a series of reports on the mineral resources, geodynamics, and metallogenesis of Northeast Asia. Companion studies include (1) a detailed geodynamics map of Northeast Asia (Parfenov and others, 2003); (2) a compilation of major mineral deposit models (Rodionov and Nokleberg, 2000; Rodionov and others, 2000); (3) a series of metallogenic belt maps (Obolenskiy and others, 2004); (4) location map of lode mineral deposits and placer districts of Northeast Asia (Ariunbileg and others, 2003b); (5) descriptions of metallogenic belts (Rodionov and others, 2004); (6) a database on significant metalliferous and selected nonmetalliferous lode deposits and selected placer districts (Ariunbileg and others, 2003a); and (7) a series of summary project publications (Ariunbileg and 74 others, 2003b).

Asia↗
USGS2019

Geology and paleontology of the late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California

An extensive fauna of at least 77 taxa is reported from the basal Wilson Grove Formation in a small quarry just north of the town of Bloomfield, Sonoma County, California. The fauna represents intertidal to shallow subtidal water depths and water temperatures interpreted from the fauna, consistent with the latitude of the fossil locality (37° north) during the late Miocene. The fauna from Bloomfield Quarry is unusually large and diverse from such a small area. It consists of thousands of specimens of 4 brachiopod, 42 mollusk (28 bivalves and 14 gastropods), 6 arthropod (1 crab, 1 shrimp, and 4 barnacles), and 25 vertebrate (3 sharks, 1 ray, 8 bony fishes, 9 marine mammals, and 4 birds) taxa. Unusual in the fauna is the abundant and diverse brachiopod fauna, the diverse barnacle fauna, which was described previously, and the extensive and diverse vertebrate fauna. Most significant among the vertebrates is the walrus fauna, which is the most diverse assemblage of walrus yet reported worldwide from a single locality. A single strontium (Sr) isotope age determination of about 8 million years (megaannum, Ma) from a pectinid mollusk is consistent with a new age determination of the overlying, informally named Roblar tuff as described by Sarna-Wojcicki in 1992 (6.203±0.011 Ma) and previously reported age determinations (recalculated here) from basalt (9.27±0.06 Ma) underlying these deposits. The Roblar tuff at Bloomfield Quarry can be correlated with other sites, including the Delgada Fan offshore northern California and the Coalinga anticline in California’s Central Valley. These age determinations conform with the “Jacalitos” California provincial molluscan stage age, the Hemphillian North American Land Mammal age determined from the fossils, and is part of the International Tortonian Stage of the Miocene.

California↗
USGS1976

Evaluation of hydrologic properties of the Long Island ground-water reservoir using cross-sectional electric-analog models

Variables necessary for constructing a quantitative model to predict the response of ground-water reservoirs to hydrologic stresses are in four classes: (a) external and internal geometry of the reservoir, (b) nature of the reservoir boundaries, (c) areal distribution of horizontal and vertical hydraulic conductivities, and (d) areal distribution of storage capability within the reservoir. In this report, the sensitivity of the Long Island ground-water reservoir's reponse to the first three of these variables was evaluated using analog models.

New York↗
USGS2020

Biology characterization breakout report

The primary goal of the biology characterization breakout group was to identify the strategies, tools, data priorities, and key partnerships needed to conduct baseline biological characterizations of deep-sea benthic environments across the U.S. EEZ in the Pacific. Discussions focused primarily on priorities for the characterization of deep-water (>200-meter depths) benthic biological communities; however, the group also emphasized that such characterizations need to be linked to efforts to characterize the overlying water column. The group was tasked with identifying how to prioritize exploration and characterization efforts, including how to identify priority geographic areas and specific methodologies needed to execute exploration activities. The expert community that provided input included representatives from various stakeholder groups actively working on deep-sea issues across the Pacific, including researchers and managers from government agencies, academic institutions, nongovernmental institutions, and the private sector. This report provides a summary of specific guidance identified as key for the successful exploration of deep-sea benthic habitats within the U.S. EEZ in the Pacific, as well as in adjacent international waters.

Conference Paper↗
USGS2005

Aquatic habitat mapping with an acoustic doppler current profiler: Considerations for data quality

When mounted on a boat or other moving platform, acoustic Doppler current profilers (ADCPs) can be used to map a wide range of ecologically significant phenomena, including measures of fluid shear, turbulence, vorticity, and near-bed sediment transport. However, the instrument movement necessary for mapping applications can generate significant errors, many of which have not been inadequately described. This report focuses on the mechanisms by which moving-platform errors are generated, and quantifies their magnitudes under typical habitat-mapping conditions. The potential for velocity errors caused by mis-alignment of the instrument?s internal compass are widely recognized, but has not previously been quantified for moving instruments. Numerical analyses show that even relatively minor compass mis-alignments can produce significant velocity errors, depending on the ratio of absolute instrument velocity to the target velocity and on the relative directions of instrument and target motion. A maximum absolute instrument velocity of about 1 m/s is recommended for most mapping applications. Lower velocities are appropriate when making bed velocity measurements, an emerging application that makes use of ADCP bottom-tracking to measure the velocity of sediment particles at the bed. The mechanisms by which heterogeneities in the flow velocity field generate horizontal velocities errors are also quantified, and some basic limitations in the effectiveness of standard error-detection criteria for identifying these errors are described. Bed velocity measurements may be particularly vulnerable to errors caused by spatial variability in the sediment transport field.

Open-File Report↗
USGS2023

A comprehensive plan for in-water sea turtle data collection in the US Gulf of Mexico

The Deepwater Horizon Open Ocean Trustee Implementation Group (OO TIG) released a Final Open Ocean Restoration Plan 2 in 2019, which included a project titled Developing a Gulf-wide Comprehensive Plan for In-water Sea Turtle Data Collection. This document, A Comprehensive Plan for In-water Sea Turtle Data Collection in the US Gulf of Mexico (Plan), is the culmination of that OO TIG project. This Plan serves as the OO TIG project’s technical report as well as a framework for a biologically and statistically-sound plan to support coordinated in-water sea turtle data collection in the United States (US) Gulf of Mexico (GoM) to determine sea turtle abundance and population trends. The purpose of this Plan is to act as a guide for collecting biologically and statistically robust, in-water sea turtle data in a comprehensive, coordinated, and standardized fashion in the US GoM. Several sea turtle in-water monitoring efforts are underway in the GoM; however, additional coordination and standardization of these efforts will benefit current restoration and recovery objectives. These efforts will aid in restoration project design, assess long-term effectiveness of restoration activities, and create abundance and distribution baselines across the GoM. This Plan provides guidance for researchers investigating sea turtle abundance and demographic questions, as well as for management agencies and restoration planners. A Steering Committee (SC) was assembled to develop this Plan and to recommend a coordinated approach to the formulation of an improved understanding of sea turtle population baselines in the GoM, from which determination of large-scale population changes, effects of specific threats (e.g., oil spills, anthropogenic hazards), and effects of changes in ocean conditions (e.g., climate change) can later be evaluated. In crafting this guidance, the SC considered species distribution and life history characteristics, spatial and logistical considerations, level of effort required to detect trends, methods available and the pros and cons of each, associated assumptions and biases with suggested monitoring methods, and standardization of data collection. Given the current level of data available, the SC has recommended species monitoring in two main phases in neritic and oceanic waters, with additional recommended sampling for surface pelagic drift communities. The two phases in this Plan focus on 1) monitoring a limited number of sites in the first 5 to 8 years, followed by 2) a refined monitoring design. To support implementation of this Plan, the SC also considered broader programmatic needs, including supplemental data collection, program and data management, potential international partnerships, program expansion, and applications including future technology.

Alabama, Florida, Louisiana, Mississippi, Texas↗
USGS2016

Elastic stress transmission and transformation (ESTT) by confined liquid: A new mechanics for fracture in elastic lithosphere of the earth

We report on a new mechanical principle, which suggests that a confined liquid in the elastic lithosphere has the potential to transmit a maximum applied compressive stress. This stress can be transmitted to the internal contacts between rock and liquid and would then be transformed into a normal compressive stress with tangential tensile stress components. During this process, both effective compressive normal stress and tensile tangential stresses arise along the liquid–rock contact. The minimum effective tensile tangential stress causes the surrounding rock to rupture. Liquid-driven fracture initiates at the point along the rock–liquid boundary where the maximum compressive stress is applied and propagates along a plane that is perpendicular to the minimum effective tensile tangential stress and also is perpendicular to the minimum principal stress. Liquid-driven fractures and dikes propagate along the axes of cylindrical zones that are perpendicular to the minimum compressive principal stress in rocks in non-tectonic regions. The minimum depth for liquid-driven fracture, which is induced by a spherical confined liquid and an isolated magma chamber in the elastic lithosphere, ranges from 2 to 6 km, whereas dikes with hemi-cylinder-shaped ends propagate upwards closer to the surface under gravity. Transmission of pumping pressure, i.e. the pressure differences on the underside of a dike that is connected with a chamber, from the source magma chamber to intermediate and shallow chambers increases liquid pressure and also the effective tensile tangential stress and therefore leads to new fractures and dike formation and to upwards transport of magmas that have stagnated in the intermediate chamber. Tectonic stress alters local stress fields in the surrounding country rocks and therefore synchronously varies the local effective tensile tangential stress and the nature and geometry of the liquid-driven fractures.

Tectonophysics↗
USGS2008

Thermal Profiles for Selected River Reaches in the Yakima River Basin, Washington

Thermal profiles (data sets of longitudinal near-streambed temperature) that provide information on areas of potential ground-water discharge and salmonid habitat for 11 river reaches in the Yakima River basin, Washington, are available as Microsoft Excel? files that can be downloaded from the Internet. Two reaches were profiled twice resulting in 13 profiles. Data were collected for all but one thermal profile during 2001. Data consist of date and time (Pacific Daylight), near-streambed water temperature, and latitude and longitude collected concurrently using a temperature probe and a Global Positioning System. The data were collected from a watercraft towing the probe with an internal datalogger while moving downstream in a Lagrangian framework.

Data Series↗
USGS2022

Virtual training prepared for the former Afghanistan Ministry of Energy and Water—Streamgaging, fluvial sediment sampling, bathymetry, and streamflow and sediment modeling

The U.S. Geological Survey (USGS) created a virtual training series for the Afghanistan Ministry of Energy and Water (MEW), now known as the National Water Affairs Regulation Authority (NWARA), to provide critical hydrological training as an alternative to an in-person training. The USGS was scheduled to provide in-person surface-water training for NWARA during 2020; however, travel was halted because of the Coronavirus disease 2019 (COVID–19) pandemic. The virtual training consisted of prerecorded and live presentations that were scheduled during 4 weeks in August 2021. However, the training was halted after the second week due to the collapse of the Afghan Government. Fortunately, the prerecorded presentations and training materials were delivered before the trainings were halted, so they can be viewed or shared by the participants in the future. A benefit to having produced prerecorded trainings is that USGS can leverage or adapt the trainings for nongovernmental organizations (NGOs) involved in humanitarian water relief efforts in Afghanistan or can be used for other international training efforts.

Fact Sheet↗