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USGS2012

Global exploration and production capacity for platinum-group metals from 1995 through 2015

Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and technological factors affecting exploration for and development of copper and nickel, as well as factors affecting the PGM industry. The recovery of PGMs from mill tailings since 2004 and the recycling of PGMs from catalytic converters, electrical components, and jewelry has increased since 1995 so that recycled PGMs recovered from these products accounted for about 30 percent of the supply of platinum worldwide and 29 percent of the supply of palladium worldwide in 2010. Economic and geopolitical conditions have influenced PGM supply and demand. The global recession of 2008 and 2009 temporarily decreased demand for PGMs and constrained PGM mine exploration and development, at least through 2010. Legislation regulating the structure of the mining sector has affected mining in Russia, South Africa, and Zimbabwe. Stricter vehicle emissions standards in established markets since the 1980s have led to mandatory use of pollution control devices, such as catalytic converters, that contain PGMs and are required on vehicles in expanding markets, such as China and India. It is expected that South Africa, Russia, Canada, and Zimbabwe will continue to be the principal sources of PGM at least for the next decade. Based on this review of the PGM industry, the world’s platinum capacity, expressed in terms of recoverable platinum metal, increased from 1995 through 2010 by 77,000 kilograms (kg) in South Africa, 9,000 kg in Zimbabwe, 6,000 kg in Russia, 2,000 kg in Botswana, and 2,000 kg in Canada. For the same period, palladium capacity worldwide increased by 44,000 kg in South Africa, 22,000 kg in Russia, 8,000 kg in Canada, 8,000 kg in the United States, 7,000 kg in Zimbabwe, and 3,000 kg in Botswana. Platinum capacity worldwide is expected to further increase by 24,000 kg in South Africa, 9,000 kg in Russia, 3,000 kg in Canada, and 2,000 kg in Zimbabwe from 2011 through 2015. Palladium capacity worldwide is likewise expected to increase an additional 16,000 kg in Russia, 14,000 kg in South Africa, 4,000 kg in Zimbabwe, and 1,000 kg in Canada if new or expanded mine and associated processing capacity comes into production as planned. It is likely that the magnitude of these changes in PGM capacity has been influenced by such factors as the global economy, electrical capacity shortages and mine safety concerns in South Africa, and geopolitical conditions in the major PGM producing countries.

Scientific Investigations Report↗

USGS2002

Threats to desert tortoise populations: a critical review of the literature

Decision in resource management are generally based on a combination of sociopolitical, economic, and environmental factors, and may be biased by personal values. These three components often contradict each other resulting in controversy. Controversies can usually be reduced when solid scientific evidence is used to support or refute a decision. However, it is important to recognize that data often do little to alter antagonists' positions when differences in values are the bases if the dispute. But, supporting data can make the decision more defensible, both legally and ethically, especially if the data supporting all opposing viewpoints are included in the decision-making process. Resource management decisions must be made using the best scientific information currently available. However, scientific data vary in two important measures of quality: reliability and validity. The reliability of the data is a measure of the degree to which the observations or conclusion can be repeated. Validity of the data is a measure of the degree to which the observation or conclusion reflects what actually occurs in nature. How the data are collected strongly affects the reliability of validity of ecological conclusions that can be made. Research data potentially relevant to management come from different sources, and the source often provides clues to the reliability and, to a certain extent, validity of data. Understanding the quality of data being used to make management decisions helps to separate the philosophical or value-based aspects of arguments from the objective ones, thus helping to clarify the decisions and judgments that need to be made. The West Mojave Plan is a multispecies, bioregional plan for the management of natural resources within a 9.4 million-acre area of the Mojave Desert in California. The plan addresses the legal requirements for the recovery of the desert tortoise ( Gopherus agazzizii ), a threatened species, but also covers an additional approximately 80 species of plants and animals assigned special status by the Bureau of Land Management, U. S. Fish and Wildlife Service, and California Department of Fish and Game. Within the planning area, 28 separate jurisdictions (counties, cities, towns, military installations, etc.) seek programmatic prescriptions that will facilitate streamlined environmental review, result in expedited authorization for development projects, and protect listed and unlisted species into the foreseeable future to avoid or minimize conflicts between proposed development and species' conservation and recovery. All of the scientific data available concerning the biology and management of these approximately 80 species and their habitats must be evaluated to develop a scientifically credible plan. This document provides an overview and evaluation of the knowledge of the major threats to the persistence and recovery of desert tortoise populations. I was specifically asked to evaluate the scientific veracity of the data and reports available. I summarize the data presently available with particular focus on the West Mojave Desert, evaluate the scientific integrity of the data. and identify major gaps in the available knowledge. I do not attempt to provide in-depth details on each study or threat; for more details I encourage the reader to consult the individual papers or reports city throughout this report (many of which are available at most university libraries and at the West Mojave Plan office in Riverside, California). I also do not attempt to characterize or evaluate the past or present management actions, except where they have direct bearing on evaluation of threats, nor do I attempt, for the most part, to acquire, generate, or evaluate new or existing, but uninterpreted data.

California↗

USGS2009

Magnitude and Frequency of Rural Floods in the Southeastern United States, through 2006: Volume 2, North Carolina

Reliable estimates of the magnitude and frequency of floods are required for the economical and safe design of transportation and water-conveyance structures. A multistate approach was used to update methods for estimating the magnitude and frequency of floods in rural, ungaged basins in North Carolina, South Carolina, and Georgia that are not substantially affected by regulation, tidal fluctuations, or urban development. In North Carolina, annual peak-flow data available through September 2006 were available for 584 sites; 402 of these sites had a total of 10 or more years of systematic record that is required for at-site, flood-frequency analysis. Following data reviews and the computation of 20 physical and climatic basin characteristics for each station as well as at-site flood-frequency statistics, annual peak-flow data were identified for 363 sites in North Carolina suitable for use in this analysis. Among these 363 sites, 19 sites had records that could be divided into unregulated and regulated/ channelized annual peak discharges, which means peak-flow records were identified for a total of 382 cases in North Carolina. Considering the 382 cases, at-site flood-frequency statistics are provided for 333 unregulated cases (also used for the regression database) and 49 regulated/channelized cases. The flood-frequency statistics for the 333 unregulated sites were combined with data for sites from South Carolina, Georgia, and adjacent parts of Alabama, Florida, Tennessee, and Virginia to create a database of 943 sites considered for use in the regional regression analysis. Flood-frequency statistics were computed by fitting logarithms (base 10) of the annual peak flows to a log-Pearson Type III distribution. As part of the computation process, a new generalized skew coefficient was developed by using a Bayesian generalized least-squares regression model. Exploratory regression analyses using ordinary least-squares regression completed on the initial database of 943 sites resulted in defining five hydrologic regions for North Carolina, South Carolina, and Georgia. Stations with drainage areas less than 1 square mile were removed from the database, and a procedure to examine for basin redundancy (based on drainage area and periods of record) also resulted in the removal of some stations from the regression database. Flood-frequency estimates and basin characteristics for 828 gaged stations were combined to form the final database that was used in the regional regression analysis. Regional regression analysis, using generalized least-squares regression, was used to develop a set of predictive equations that can be used for estimating the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent chance exceedance flows for rural ungaged, basins in North Carolina, South Carolina, and Georgia. The final predictive equations are all functions of drainage area and the percentage of drainage basin within each of the five hydrologic regions. Average errors of prediction for these regression equations range from 34.0 to 47.7 percent. Discharge estimates determined from the systematic records for the current study are, on average, larger in magnitude than those from a previous study for the highest percent chance exceedances (50 and 20 percent) and tend to be smaller than those from the previous study for the lower percent chance exceedances when all sites are considered as a group. For example, mean differences for sites in the Piedmont hydrologic region range from positive 0.5 percent for the 50-percent chance exceedance flow to negative 4.6 percent for the 0.2-percent chance exceedance flow when stations are grouped by hydrologic region. Similarly for the same hydrologic region, median differences range from positive 0.9 percent for the 50-percent chance exceedance flow to negative 7.1 percent for the 0.2-percent chance exceedance flow. However, mean and median percentage differences between the estimates from the previous and curre

North Carolina↗

USGS2023

Integrated rangeland fire management strategy actionable science plan completion assessment — Sagebrush and sage-grouse topic, 2015–20

Loss and degradation of sagebrush rangelands due to an accelerated invasive annual grass-wildfire cycle and other stressors are significant management, conservation, and economic issues in the western United States. These sagebrush rangelands comprise a unique biome spanning 11 states, support over 350 wildlife species, and provide important ecosystem services that include stabilizing the economies of western communities. Impacts to sagebrush ecosystem processes over large areas due to the annual grass-wildfire cycle necessitated the development of a coordinated, science-based strategy for improving efforts to achieve long-term protection, conservation, and restoration of sagebrush rangelands, which was framed in 2015 under the Integrated Rangeland Fire Management Strategy (IRFMS). Central to this effort was the development of an Actionable Science Plan (Plan) that identified 37 priority science needs (Needs) for informing the actions proposed under the 5 topics (Fire, Invasives, Restoration, Sagebrush and Sage-Grouse, Climate and Weather) that were part of the collective focus of the IRFMS. Notable keys to this effort were identification of the Needs co-produced by managers and researchers, and a focus on resulting science being “actionable.” Substantial investments aimed at fulfilling the Needs identified in the Plan have been made since its release in 2016. While the state of the science has advanced considerably, the extent to which knowledge gaps remain relative to identified Needs is relatively unknown. Moreover, new Needs have likely emerged since the original strategy as results from actionable science reveal new questions and possible (yet untested) solutions. A quantifiable assessment of the progress made on the original science Needs can identify unresolved gaps and new information that can help inform prioritization of future research efforts. This report details a systematic literature review that evaluated how well peer-reviewed journal articles and formal technical reports published between January 1, 2015, and December 31, 2020, addressed nine needs (hereinafter, “Needs”) identified under the Sagebrush and Sage-Grouse topic in the Plan. The topic outlined research Needs broadly focused on understanding sagebrush rangelands and population dynamics important for the conservation and management of sage-grouse and other sagebrush-reliant wildlife species. We established the level of progress towards addressing each Need following a standardized set of criteria, and developed summaries detailing how research objectives nested within Needs identified in the Plan (‘Next Steps’) were either addressed well, partially addressed or remain outstanding (in other words, addressed poorly) in the literature through 2020. Our searches resulted in the inclusion of 333 science products that at least partially addressed a Need identified in the Sagebrush and Sage-Grouse topic. The Needs that were well and partially addressed included: development of biome-wide mapping techniques that provide regularly updated grassland and shrubland vegetation layers (Need 4); generation of spatially explicit greater sage-grouse habitat suitability and population models (Need 5); identification of greater sage-grouse seasonal habitats (Need 6); identification of thresholds for the extent of threats, especially conifer expansion, above which greater sage-grouse and other sagebrush-obligate species cannot persist (Need 8); and studies of sagebrush community dynamics as those relate to management and restoration of sagebrush rangelands (Need 9). Needs addressed poorly included: investigations of factors conducive and restrictive to greater sage-grouse movement patterns and population connectivity (Need 1); investigations of livestock and other large ungulate (for example, feral horse) grazing effects on greater sage-grouse populations and habitats (Need 2); identification of thresholds of disturbance (especially renewable energy developments) below which greater sage-grouse and other sagebrush reliant species are not impacted (Need 3); and studies of habitat relationships for sagebrush-reliant species other than greater sage-grouse, songbirds, and small mammals (Need 7). The information provided in this assessment will assist updating the Plan along with other science strategies.

western United States↗

USGS2026

Small creatures, big challenge: A review of current knowledge and assessment of research needs to inform water withdrawal management for the Duck River's freshwater mussel fauna

The Duck River is a remarkable national resource, boasting outstanding biodiversity (Ahlstedt et al. 2017). It contains 151 fish species, over 60 mussel species, and 22 snail species, many of which are federally listed (Etnier and Starnes 1993; Johnson et al. 2013; Ahlstedt et al. 2017; Womble and Rosenberger 2025a). The Duck River watershed is at a pivotal time in its management and ecological history due to significant growth in human population and economic activity. The consequent increase in surface water demand presents challenges for sustainable water resource management. The Tennessee Department of Environment and Conservation (TDEC) has permitted or proposed to permit eight water utilities to withdraw over 77 million gallons per day (mgd) from the Duck River, representing > 40% increase from previously permitted amounts (USFWS 2025). On November 20, 2024, Tennessee Governor Bill Lee signed Executive Order No 108 to ensure long-term stability of the Duck River watershed through balancing economic growth, water resource management, and environmental conservation. Some primary components of this plan are the creation of a Comprehensive Regional Drought Management Plan, the development of a Habitat Conservation Plan, and the establishment of the Duck River Watershed Planning Partnership (DRWPP). Although the planning partnership is not focused on a sole aspect of the Duck River, but the watershed as a whole, the mussel assemblages of the Duck River have been a particular focus due to their importance in providing ecosystem services, sensitivity to water quality, conservation status, and sensitivity to periodic drought conditions in this system. With multiple state and federal agencies involved in managing the Duck River’s unique water resources, a focused review on how future water management could affect the freshwater mussel communities in the Duck River will contribute to this process. Our objectives of this review are to: 1. Review the effects of changing flow regimes on mussels, with emphasis on the effect of droughts/low flows, highlighting key processes/factors affecting mussels. 2. Highlight critical data gaps that could allow future, evidence-based water management decisions in this system. 3. Propose research topics to address critical data gaps and enable evidence-based water management decisions that consider the needs of freshwater mussels. Freshwater mussels are a critical component of riverine ecosystems, providing ecosystem services including water filtration, nutrient cycling, and habitat provision (Vaughn et al. 2004; Haag 2012) that benefit human communities. Environmental flows, also referred to as ecological or e-flows, refer to the quantity, timing, and quality of water flows necessary to maintain the ecological health of rivers, wetlands, and other aquatic ecosystems (Acreman and Dunbar 2004; Acreman 2016). For freshwater mussels, environmental flows include maintaining a flow regime and associated water quality regimes that are favorable for both juveniles and adults while also seasonally supporting host fish and the survival of settling glochidia (i.e., larval mussels) in suitable environments (Gates et al. 2015). Freshwater mussels are adapted to the natural flow regime of their native streams, including seasonal variability in flows. As sedentary filter feeders, mussels require adequate water flow to provide oxygen and food (Allen and Vaughn 2009); however, they also require periods of low flow to increase access to fish hosts and to ensure juveniles are not displaced (Gates et al 2015). Mussels are sensitive to water quality conditions, including pollutants, sedimentation, and artificial alterations of temperature and pH (Strayer and Malcom 2012). Mussel community characteristics, including presence, abundance, and species richness, generally increase with stream size (e.g., stream order); however, responses to changes in flow conditions are often species-specific, and the magnitude and timing of extreme flow conditions have more predictive power for mussel community response than general changes in flow (Lopez and Vaughn 2021). Complex hydraulic variables, such as relative shear stress and Reynolds number, can be strong predictors of mussel community responses because they combine simple hydraulic variables (e.g., velocity, depth) with stream channel characteristics, such as substrate composition and dynamics. Droughts directly and indirectly affect mussels by influencing their physiology, behavior, reproduction, and ecosystem roles. Mass mussel die-offs during droughts and low water conditions are widely documented (Vaughn et al. 2015; Sousa et al. 2018; Dubose et al. 2019). Droughts can also lead to a shift in mussel community composition, with drought-tolerant species becoming more dominant while more sensitive species experience declines (Galbraith et al, 2010; Lopez et al. 2022; Vaughn and Atkinson 2025). Droughts affect mussels through direct mortality from stranding as well as physiological stress from altered water temperature and quality, reduced habitat and food availability and quality, increased predation and competition, disruption of reproductive cycles, and increased susceptibility to disease and pathogens. Although the effects of droughts, water withdrawals, and low flow conditions on mussels are an increasing area of study, there is a general paucity of data-driven consensus regarding optimal mitigation approaches and strategies (Cushway et al. 2024). Long-term management decisions regarding water withdrawals, particularly during extended or multi-year drought conditions, may consider factors beyond direct mortality such as the sublethal effects of drought and low flow conditions on freshwater mussels for a comprehensive understanding of the effects of prolonged low flows on freshwater mussels and aquatic communities.

Tennessee↗

USGS2012

Prioritizing pesticide compounds for analytical methods development

The U.S. Geological Survey (USGS) has a periodic need to re-evaluate pesticide compounds in terms of priorities for inclusion in monitoring and studies and, thus, must also assess the current analytical capabilities for pesticide detection. To meet this need, a strategy has been developed to prioritize pesticides and degradates for analytical methods development. Screening procedures were developed to separately prioritize pesticide compounds in water and sediment. The procedures evaluate pesticide compounds in existing USGS analytical methods for water and sediment and compounds for which recent agricultural-use information was available. Measured occurrence (detection frequency and concentrations) in water and sediment, predicted concentrations in water and predicted likelihood of occurrence in sediment, potential toxicity to aquatic life or humans, and priorities of other agencies or organizations, regulatory or otherwise, were considered. Several existing strategies for prioritizing chemicals for various purposes were reviewed, including those that identify and prioritize persistent, bioaccumulative, and toxic compounds, and those that determine candidates for future regulation of drinking-water contaminants. The systematic procedures developed and used in this study rely on concepts common to many previously established strategies. The evaluation of pesticide compounds resulted in the classification of compounds into three groups: Tier 1 for high priority compounds, Tier 2 for moderate priority compounds, and Tier 3 for low priority compounds. For water, a total of 247 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods for monitoring and studies. Of these, about three-quarters are included in some USGS analytical method; however, many of these compounds are included on research methods that are expensive and for which there are few data on environmental samples. The remaining quarter of Tier 1 compounds are high priority as new analytes. The objective for analytical methods development is to design an integrated analytical strategy that includes as many of the Tier 1 pesticide compounds as possible in a relatively few, cost-effective methods. More than 60 percent of the Tier 1 compounds are high priority because they are anticipated to be present at concentrations approaching levels that could be of concern to human health or aquatic life in surface water or groundwater. An additional 17 percent of Tier 1 compounds were frequently detected in monitoring studies, but either were not measured at levels potentially relevant to humans or aquatic organisms, or do not have benchmarks available with which to compare concentrations. The remaining 21 percent are pesticide degradates that were included because their parent pesticides were in Tier 1. Tier 1 pesticide compounds for water span all major pesticide use groups and a diverse range of chemical classes, with herbicides and their degradates composing half of compounds. Many of the high priority pesticide compounds also are in several national regulatory programs for water, including those that are regulated in drinking water by the U.S. Environmental Protection Agency under the Safe Drinking Water Act and those that are on the latest Contaminant Candidate List. For sediment, a total of 175 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods available for monitoring and studies. More than 60 percent of these compounds are included in some USGS analytical method; however, some are spread across several research methods that are expensive to perform, and monitoring data are not extensive for many compounds. The remaining Tier 1 compounds for sediment are high priority as new analytes. The objective for analytical methods development for sediment is to enhance an existing analytical method that currently includes nearly half of the pesticide compounds in Tier 1 by adding as many additional Tier 1 compounds as are analytically compatible. About 35 percent of the Tier 1 compounds for sediment are high priority on the basis of measured occurrence. A total of 74 compounds, or 42 percent, are high priority on the basis of predicted likelihood of occurrence according to physical-chemical properties, and either have potential toxicity to aquatic life, high pesticide useage, or both. The remaining 22 percent of Tier 1 pesticide compounds were either degradates of Tier 1 parent compounds or included for other reasons. As with water, the Tier 1 pesticide compounds for sediment are distributed across the major pesticide-use groups; insecticides and their degradates are the largest fraction, making up 45 percent of Tier 1. In contrast to water, organochlorines, at 17 percent, are the largest chemical class for Tier 1 in sediment, which is to be expected because there is continued widespread detection in sediments of persistent organochlorine pesticides and their degradates at concentrations high enough for potential effects on aquatic life. Compared to water, there are fewer available benchmarks with which to compare contaminant concentrations in sediment, but a total of 19 Tier 1 compounds have at least one sediment benchmark or screening value for aquatic organisms. Of the 175 compounds in Tier 1, 77 percent have high aquatic-life toxicity, as defined for this process. This evaluation of pesticides and degradates resulted in two lists of compounds that are priorities for USGS analytical methods development, one for water and one for sediment. These lists will be used as the basis for redesigning and enhancing USGS analytical capabilities for pesticides in order to capture as many high-priority pesticide compounds as possible using an economically feasible approach.

Scientific Investigations Report↗

USGS2000

Late-kinematic timing of orogenic gold deposits and significance for computer-based exploration techniques with emphasis on the Yilgarn Block, Western Australia

Orogenic gold deposits are a widespread coherent group of epigenetic ore deposits that are sited in accretionary or collisional orogens. They formed over a large crustal-depth range from deep-seated low-salinity H 2 O–CO 2 ±CH 4 ±N 2 ore fluids and with Au transported as thio-complexes. Regional structures provide the main control on deposit distribution. In many terranes, first-order faults or shear zones appear to have controlled regional fluid flow, with greatest ore-fluid fluxes in, and adjacent to, lower-order faults, shear zones and/or large folds. Highly competent and/or chemically reactive rocks are the most common hosts to the larger deposits. Focusing of supralithostatic ore fluids into dilatant zones appears to occur late during the evolutionary history of the host terranes, normally within D 3 or D 4 in a D 1 –D 4 deformation sequence. Reactivation of suitably oriented pre-existing structures during a change in far-field stress orientation is a factor common to many deposits, and repeated reactivation may account for multiple mineralization episodes in some larger deposits. Absolute robust ages of mineralization support their late-kinematic timing, and, in general, suggest that deposits formed diachronously towards the end of the 100 to 200 m.y. long evolutionary history of hosting orogens. For example, in the Yilgarn Block, a region specifically emphasised in this study, orogenic gold deposits formed in the time interval between 40 and 90 m.y., with most about 60 to 70 m.y., after the youngest widespread basic-ultrabasic volcanism and towards the end of felsic magmatism. The late timing of orogenic gold deposits is pivotal to geologically-based exploration methodologies. This is because the present structural geometries of: (i) the deposits, (ii) the hosting goldfields, and (iii) the enclosing terranes are all essentially similar to those during gold mineralization, at least in their relative position to each other. Thus, interpretation of geological maps and cross-sections and three-dimensional models can be used to accurately simulate the physical conditions that existed at the time of ore deposition. It is particularly significant that the deposits are commonly related to repetitive and predictable geometries, such as structural heterogeneities within or adjacent to first-order structures, around rigid granitoid bodies, or in specific “locked-up” fold-thrust structures. Importantly, the two giant greenstone-hosted goldfields, Kalgoorlie and Timmins, show a remarkably similar geometry at the regional scale. Computer-based stress mapping and GIS-based prospectivity mapping are two computer-based quantitative methodologies that can utilize and take advantage of the late timing aspect of this deposit type to provide important geological aids in exploration, both in broad regions and more localized goldfields. Both require an accurate and consistent solid geology map, stress mapping requires knowledge of the far-field stresses during mineralization, and the empirical prospectivity mapping requires data from a significant number of known deposits in the terrane. The Kalgoorlie Terrane, in the Yilgarn Block, meets these criteria, and illustrates the potential of these methodologies in the exploration for orogenic gold deposits. Low minimum stress anomalies, interpreted to represent dilational zones during gold-related deformation, coincide well with the positions of known goldfields rather than individual gold deposits in the terrane, and there are additional as-yet unexplained anomalies. The prospectivity analysis confirms that predictable and repetitive factors controlling the siting of deposits are: (i) proximity to, and orientation and curvature of, granitoid-greenstone contacts, (ii) proximity to segments of crustal faults which strike in a preferred direction, (iii) proximity to specific lithological contacts which have similar preferred strike, (iv) proximity to anticlinal structures, and (v) the presence of preferred reactive host rocks (e.g., dolerite). The prospectivity map defines a series of anomalous areas, which broadly conform to those of the stress map (>78% correspondence). The most prospective category on this map covers less than 0.3% of the greenstone belts and yet hosts 16% of the known deposits, which have produced>80% of known gold. Thus, it discriminates in favour of the larger economically more-attractive deposits in the terrane. The successful application of stress mapping and prospectivity mapping to geology-based exploration for orogenic gold deposits indicates that more quantitative analysis of geological map data is a profitable line of research. The computer-based nature of these methodologies is ideal for the production of an ultimate, integrated, deposit target map, which can be compared to other, more conventional, targeting parameters such as geophysical and geochemical anomalies. Such an integrated strategy appears the way forward in the increasingly difficult task of cost-effective global exploration for orogenic gold deposits in poorly exposed terranes.

Western Australia↗

USGS2013

Historical methane hydrate project review

In 1995, U.S. Geological Survey made the first systematic assessment of the volume of natural gas stored in the hydrate accumulations of the United States. That study, along with numerous other studies, has shown that the amount of gas stored as methane hydrates in the world greatly exceeds the volume of known conventional gas resources. However, gas hydrates represent both a scientific and technical challenge and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of gas hydrates in nature, (2) assessing the volume of natural gas stored within various gas hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural gas hydrates, and (5) analyzing the effects of methane hydrate on drilling safety. Methane hydrates are naturally occurring crystalline substances composed of water and gas, in which a solid water-‐lattice holds gas molecules in a cage-‐like structure. The gas and water becomes a solid under specific temperature and pressure conditions within the Earth, called the hydrate stability zone. Other factors that control the presence of methane hydrate in nature include the source of the gas included within the hydrates, the physical and chemical controls on the migration of gas with a sedimentary basin containing methane hydrates, the availability of the water also included in the hydrate structure, and the presence of a suitable host sediment or “reservoir”. The geologic controls on the occurrence of gas hydrates have become collectively known as the “methane hydrate petroleum system”, which has become the focus of numerous hydrate research programs. Recognizing the importance of methane hydrate research and the need for a coordinated effort, the U.S. Congress enacted Public Law 106-‐193, the Methane Hydrate Research and Development Act of 2000. This Act called for the Secretary of Energy to begin a methane hydrate research and development program in consultation with other U.S. federal agencies. At the same time a new methane hydrate research program had been launched in Japan by the Ministry of International Trade and Industry to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. Since this early start we have seen other countries including India, China, Canada, and the Republic of Korea establish large gas hydrate research and development programs. These national led efforts have also included the investment in a long list of important scientific research drilling expeditions and production test studies that have provided a wealth of information on the occurrence of methane hydrate in nature. The most notable expeditions and projects have including the following: -‐Ocean Drilling Program Leg 164 (1995) -‐Japan Nankai Trough Project (1999-‐2000) -‐Ocean Drilling Program Leg 204 (2004) -‐Japan Tokai-‐oki to Kumano-‐nada Project (2004) -‐Gulf of Mexico JIP Leg I (2005) -‐Integrated Ocean Drilling Program Expedition 311 (2005) -‐Malaysia Gumusut-‐Kakap Project (2006) -‐India NGHP Expedition 01 (2006) -‐China GMGS Expedition 01 (2007) -‐Republic of Korea UBGH Expedition 01 (2007) -‐Gulf of Mexico JIP Leg II (2009) -‐Republic of Korea UBGH Expedition 02 (2010) -‐MH-‐21 Nankai Trough Pre-‐Production Expedition (2012-‐2013) -‐Mallik Gas Hydrate Testing Projects (1998/2002/2007-‐2008) -‐Alaska Mount Elbert Stratigraphic Test Well (2007) -‐Alaska Iġnik Sikumi Methane Hydrate Production Test Well (2011-‐2012) Research coring and seismic programs carried out by the Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP), starting with the ODP Leg 164 drilling of the Blake Ridge in the Atlantic Ocean in 1995, have also contributed greatly to our understanding of the geologic controls on the formation, occurrence, and stability of gas hydrates in marine environments. For the most part methane hydrate research expeditions carried out by the ODP and IODP provided the foundation for our scientific understanding of gas hydrates. The methane hydrate research efforts under ODP-‐IODP have mostly dealt with the assessment of the geologic controls on the occurrence of gas hydrate, with a specific goal to study the role methane hydrates may play in the global carbon cycle. Over the last 10 years, national led methane hydrate research programs, along with industry interest have led to the development and execution of major methane hydrate production field test programs. Two of the most important production field testing programs have been conducted at the Mallik site in the Mackenzie River Delta of Canada and in the Eileen methane hydrate accumulation on the North Slope of Alaska. Most recently we have also seen the completion of the world’s first marine methane hydrate production test in the Nankai Trough in the offshore of Japan. Industry interest in gas hydrates has also included important projects that have dealt with the assessment of geologic hazards associated with the presence of hydrates. The scientific drilling and associated coring, logging, and borehole monitoring technologies developed in the long list of methane hydrate related field studies are one of the most important developments and contributions associated with methane hydrate research and development activities. Methane hydrate drilling has been conducted from advanced scientific drilling platforms like the JOIDES Resolution and the D/V Chikyu, which feature highly advanced integrated core laboratories and borehole logging capabilities. Hydrate research drilling has also included the use of a wide array of industry, geotechnical and multi-‐service ships. All of which have been effectively used to collect invaluable geologic and engineering data on the occurrence of methane hydrates throughout the world. Technologies designed specifically for the collection and analysis of undisturbed methane hydrate samples have included the development of a host of pressure core systems and associated specialty laboratory apparatus. The study and use of both wireline conveyed and logging-‐while-‐drilling technologies have also contributed greatly to our understanding of the in-‐situ nature of hydrate-‐bearing sediments. Recent developments in borehole instrumentation specifically designed to monitor changes associated with hydrates in nature through time or to evaluate the response of hydrate accumulations to production have also contributed greatly to our understanding of the complex nature and evolution of methane hydrate systems. Our understanding of how methane hydrates occur and behave in nature is still growing and evolving – we do not yet know if methane hydrates can be economically produced, nor do we know fully the role of hydrates as an agent of climate change or as a geologic hazard. But it is known for certain that scientific drilling has contributed greatly to our understanding of hydrates in nature and will continue to be a critical source of the information to advance our understanding of methane hydrates.

Report↗

USGS2024

Analysis and review of fishery-dependent data for Hawaiian nearshore noncommercial fisheries

Noncommercial, shore-based fisheries provide economic, social, and cultural services to communities throughout the Hawaiian Islands. The State of Hawai‘i Department of Land and Natural Resources (DLNR), Division of Aquatic Resources (DAR) routinely conducts surveys to monitor noncommercial fisheries such that estimates of fishing effort and catch by gear type can be generated and used to implement more sustainable management practices. DAR executes both the Hawai‘i Marine Recreational Fishery Survey (HMRFS), a nationally standardized survey that focuses on intercepting fishers at access points (i.e., boat ramps) across the main Hawaiian Islands, and a set of roving creel surveys on O‘ahu, Maui Nui, and Kaua‘i that observe and intercept fishers at locations along the shoreline outside of those targeted by HMRFS. The latter set of creel surveys were designed to complement HMRFS by expanding its geographic coverage and thus providing a more representative picture of noncommercial fishing in Hawai‘i. Sustainable management priorities set by DAR rely on the availability of statewide, fishery- dependent data. Thus, we collate information from island-based roving creel surveys into a cohesive Statewide Creel Survey Database. Further, we provide preliminary analyses and describe ways that surveys could be streamlined to improve future data collection, analysis, and utility. In so doing, we synthesize the most detailed information to-date about noncommercial shore-based fisheries of Hawai‘i. The unprecedented spatial and temporal coverage of DAR’s dataset reveals the value of their survey efforts over the last decade to address fishery management needs. Our primary objectives, results, and conclusions are summarized below: 1) Integrate DAR roving creel survey data from different islands into a single Statewide Creel Survey Dataset (Chapter II). We describe the collation of creel survey data from O‘ahu, Maui Nui, and Kaua‘i into a statewide dataset. We also offer ways in which these surveys could be streamlined to meet the needs of managers and decision makers. Briefly, these are to create a statewide strategic plan, standardize the execution of standard operating procedures, centralize the creel survey database and associated metadata, and consider using technology that improves the data pipeline, including transitioning from paper-based to electronic systems for data entry and processing. 2) Assess whether the new Statewide Creel Survey Dataset can provide inputs for length-based stock assessments (Chapter III). Only on Maui were interviews conducted with associated catch data. There was reasonably high taxonomic coverage (42 species from 186 interviews with 310 fishers), but low sample sizes for nearly all species precluded the development of length-based stock assessments. We provide summary statistics from the existing data and briefly discuss how technologies could be used to automate analysis of images of noncommercial catch. 3) Analyze the Statewide Creel Survey Dataset for spatial and temporal patterns in fishing effort (Chapter IV): a. Visualizing noncommercial fishing pressure . We found that fishing effort (mean number of fishers observed per survey event at a site) on O'ahu was over three times greater than that recorded during similar surveys conducted on Maui or Kaua'i. We create maps that display the distribution of angling and spearfishing effort around each of the three islands. b. Factors that predict fishing “hotspots” around Maui . Fishing effort on Maui was associated with areas with more wave power and less parking availability. There were half as many fishers in areas with parking lots than in areas with parking on the road shoulder only. c. Changes in fishing effort during the COVID-19 pandemic . There was no change in fishing effort on O‘ahu during the first year of the pandemic, but there was a 20% decline in year 2 and a 33% decline in year 3, both in comparison to pre-pandemic levels. Pre-pandemic creel survey data were unavailable for Maui and Kaua‘i, but fishing effort on these islands also declined as the pandemic progressed at similar or greater rates than those observed on O‘ahu. 4) Quantify potential bias in survey methods by experimentally deriving fisher detection probabilities of shore-based and drone-based surveys (Chapter V): a. Shore-based surveys . We conducted roving creel surveys for four months at three locations around Hilo Bay, designed to emulate and estimate the efficacy of DAR standard operating procedures. There was high agreement between paired observers in counting fishers, leading to near-perfect detection probabilities of both anglers (94%) and spearfishers (97%), but relatively low agreement and detection probabilities of other fishers (throw net, ‘opihi picking, etc.) (52%). b. Drone-based surveys . We used an unmanned aerial vehicle (UAV; operated by DAR staff) to collect imagery of fishers along the Hilo Bay shoreline. We used still images and video clips (with known fishing activity) to build an online survey that was distributed to DAR and HCFRU personnel, asking them to count and categorize resource users as a snorkeler, spearfisher, angler, or other fisher. Only 40.0% of the responses correctly counted and categorized resource users in the image. Anglers were correctly identified and enumerated in 90.0% of the responses, but the correct response rates of the other three user categories ranged from 67.8% – 79.4%. Snorkelers and anglers tended to be undercounted while spearfishers and other fishers were overcounted. 5) Review the potential for incorporating emerging technologies that will improve, augment, and evolve creel survey data collection, especially for spearfishing (Chapter VI). Within the context of monitoring shore-based noncommercial fishing, we review the use of electronic data entry/processing systems with geospatial and image capabilities, field cameras, drones, smart buoys, citizen science apps, data mining social media, artificial intelligence and machine learning. We highlight several of the challenges and considerations when implementing these technologies into creel surveys and provide a synthesis of options that could be used to better estimate spearfishing. The general conclusion of this assessment is that the DAR roving creel survey program is collecting valuable data that supplement the existing HMRFS efforts. However, there are a number of areas that could be improved to make these efforts a more effective tool for decision-making processes in resource management and conservation: 1) Establishment of clear statewide and island objectives for the Statewide Creel Survey Dataset. Currently, data collection efforts are focused towards addressing a very broad purpose – supplementing the HMRFS data collection efforts. However, the results of the preliminary analyses conducted as part of this project suggest that the data could be used to address other areas of need if these objectives were clearly defined. Further, the design of the creel survey would benefit from greater standardization of survey protocols between islands and an effort to define a) the acceptable margins of error associated with the estimates generated by these data and b) the minimum level of change that the surveys would need to detect to be useful to managers. 2) Centralization of data entry, data quality assessment, and data accessibility. Currently, each DAR office manages data entry, checks the data for errors, and is responsible for managing and storing the data. Instituting a centralized data entry system, particularly an online database that can receive survey data from tablets or smartphones running a standardized data collection application would improve efficiency, reduce data entry errors, and accelerate the availability of data to managers. A substantial amount of time and effort from the project described in this report was devoted to checking the dataset for errors. The development and application of data quality assurance protocols would ensure that the data are reliable and available in a timely fashion to support management decisions. 3) Address lingering questions regarding the efficacy of current survey protocols to capture and characterize the spearfishing component of the noncommercial fishery. The results presented in the report suggest that the current creel survey protocols do a good job detecting spearfishers when present but are not capturing sufficient data about their catch or total effort. There are also questions remaining as to whether the survey times and sites are sufficiently capturing the behavior of spearfishers in Hawai‘i. A more thorough assessment – whether through additional research, alteration of survey design, or review of data by representatives of the spearfishing community – would provide insight on how to use the Statewide Creel Survey Database to inform management of spearfishing. 4) Investigate the integration of technological advancements into the creel survey methods. As priorities and needs are developed and formalized, it would be valuable to consider how various technological advancements might enhance and streamline data collection or open new avenues of inquiry.

Hawaii↗