USGS Science⌕ Search

SEARCH · USGS Science

Results for “World & I”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources

Strontium

China, Mexico, Spain and Turkey are the world's leading producers of celestite (strontium sulphate). These countries accounted for 98% of the total world production in 2005. For the same period, US apparent consumption of strontium decreased to 12.3 kt. Imports were 21.2 kt, of which 84% came from Mexico. Imports of celestite and strontium carbonate decreased 71% and 24% respectively.

Mining Engineering↗

Industrial sand and gravel

In 2005, domestic production of industrial sand and gravel was about 31 Mt, a 5% increase from 2004. This increase was bouyed by robust construction and petroleum sectors of the US economy. Based on estimated world production figures, the United States was the world's leading producer and consumer of industrial sand and gravel. In the short term, local shortages of industrial sand and gravel will continue to increase.

Mining Engineering↗

Magnesium compounds

In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

Mining Engineering↗

Climate-induced forest dieback: An escalating global phenomenon?

Forests, which today cover 30 percent of the world’s land surface (FAO, 2006), are being rapidly and directly transformed in many areas by the impacts of expanding human populations and economies. Less evident are the pervasive effects of ongoing climatic changes on the condition and status of forests around the world. Recent examples of drought and heat-related forest stress and dieback (defined here as tree mortality noticeably above usual mortality levels) are being documented from all forested continents, making it possible to begin to see global patterns. This article introduces these patterns and considers the possibility that many forests and woodlands today are at increasing risk of climate-induced dieback. A more comprehensive article (Allen et al. , 2009) addresses this topic in considerably greater detail. While climate events can damage forests in many ways ranging from ice storms to tornadoes and hurricanes, the emphasis here is on climatic water stress, driven by drought and warm temperatures.

Unasylva↗

Impacts of climate change on biodiversity, ecosystems, and ecosystem services: technical input to the 2013 National Climate Assessment

Ecosystems, and the biodiversity and services they support, are intrinsically dependent on climate. During the twentieth century, climate change has had documented impacts on ecological systems, and impacts are expected to increase as climate change continues and perhaps even accelerates. This technical input to the National Climate Assessment synthesizes our scientific understanding of the way climate change is affecting biodiversity, ecosystems, ecosystem services, and what strategies might be employed to decrease current and future risks. Building on past assessments of how climate change and other stressors are affecting ecosystems in the United States and around the world, we approach the subject from several different perspectives. First, we review the observed and projected impacts on biodiversity, with a focus on genes, species, and assemblages of species. Next, we examine how climate change is affecting ecosystem structural elements—such as biomass, architecture, and heterogeneity—and functions—specifically, as related to the fluxes of energy and matter. People experience climate change impacts on biodiversity and ecosystems as changes in ecosystem services; people depend on ecosystems for resources that are harvested, their role in regulating the movement of materials and disturbances, and their recreational, cultural, and aesthetic value. Thus, we review newly emerging research to determine how human activities and a changing climate are likely to alter the delivery of these ecosystem services. This technical input also examines two cross-cutting topics. First, we recognize that climate change is happening against the backdrop of a wide range of other environmental and anthropogenic stressors, many of which have caused dramatic ecosystem degradation already. This broader range of stressors interacts with climate change, and complicates our abilities to predict and manage the impacts on biodiversity, ecosystems, and the services they support. The second cross-cutting topic is the rapidly advancing field of climate adaptation, where there has been significant progress in developing the conceptual framework, planning approaches, and strategies for safeguarding biodiversity and other ecological resources. At the same time, ecosystem-based adaptation is becoming more prominent as a way to utilize ecosystem services to help human systems adapt to climate change. In this summary, we present key findings of the technical input, focusing on themes that can be found throughout the report. Thus, this summary takes a more integrated look at the question of how climate change is affecting our ecological resources, the implications for humans, and possible response strategies. This integrated approach better reflects the impacts of climate in the real world, where changes in ecosystem structure or function will alter the viability of different species and the efficacy of ecosystem services. Likewise, adaptation to climate change will simultaneously address a range of conservation goals. Case studies are used to illustrate this complete picture throughout the report; a snapshot of one case study, 2011 Las Conchas, New Mexico Fire , is included in this summary.

Report↗

Atlas of nonindigenous marine and estuarine species in the North Pacific

Executive Summary Marine and estuarine nonindigenous species (NIS) are found across the world’s oceans, and designing effective management strategies to mitigate this economic, ecological and human health threat requires a basic understanding of the existing invasion patterns at regional to global scales. However, to date, syntheses at ocean basin scales have essentially been nonexistent. To fill the gap for the North Pacific, we synthesized the distributions, invasion history, environmental tolerances, and natural history of the near-coastal nonindigenous species (NIS) reported from the member countries of the North Pacific Marine Science Organization (PICES; United States, Canada, China, Republic of Korea, Japan, and Russia). The hierarchical “Marine Ecoregions of the World” (MEOW) biogeographic schema was used as the framework for assessing species’ distributions, with the modification that we added a “region” level to differentiate eastern and western sides of oceans. The two North Pacific regions are the Northeast Pacific (NEP), which extends from the Gulf of California to the Aleutian Islands, and the Northwest Pacific (NWP), which extends from the East China Sea to the Kamchatka Shelf. To have complete coverage of the United States, we included the MEOW Hawaii Ecoregion as a separate reporting unit. To have complete coverage of Japan and China, we combined five MEOW ecoregions in southern China and Japan into the North Central-Indo Pacific (NCIP) Region. The various types of information were synthesized in a Microsoft Access database, the “PICES Nonindigenous Species Information System”, which is further described in the “User’s Guide and Metadata for the PICES Nonindigenous Species Information System” (Lee et al., 2012). The PICES database was then used to generate two-page “species profiles” that map the native and introduced distributions of each species and provide a standardized summary of its invasion history, environmental tolerances, and natural history. These species profiles form the bulk of the “Atlas of Nonindigenous Marine and Estuarine Species in the North Pacific”. A total of 747 near-coastal nonindigenous species were identified in the PICES countries, with four phyla (Arthropoda, Chordata, Mollusca, and Annelida) constituting more than 70% of these invaders. The NEP and Hawaii have similar numbers of reported nonindigenous species, 368 and 347, respectively. In comparison, the NWP has about 60% of the number of reported NIS, 208. The NCIP contains only 73 NIS, though there is limited information for these ecoregions. When evaluated at an individual MEOW ecoregion scale, the Hawaii Ecoregion was the most invaded with 347 invaders, followed by the Northern California Ecoregion, which includes the San Francisco Estuary, with 287 NIS. The most invaded ecoregion in the NWP was the Central Kuroshio Current Ecoregion, which includes Tokyo Bay, with 87 reported NIS. Eight potential reasons for this geographical discrepancy in the extent of invasion were considered. The two most important appear to be: 1) the milder temperature regimes in the NEP and Hawaii are more conducive for NWP species to invade the NEP and Hawaii than the reverse and 2) there has been a greater search effort for NIS in Hawaii and the NEP at least for certain taxonomic groups. In terms of how the NIS were transported, hull fouling was potentially the most important vector in the NEP, NWP, and Hawaii, with ballast water discharges the second most important in all three regions. Intentional stocking and aquaculture escapees were relatively more important in the NWP than the NEP or Hawaii, reflecting the extensive aquaculture in Asia. Aquaculture associated species (i.e., aquaculture hitchhikers) was relatively important in the NEP, reflecting the historical influx of invaders with the importation of Atlantic and Pacific oysters.

Report↗

Mineral resource of the month: lead

The United States is a major producer and consumer of refined lead, representing almost one quarter of total world production and consumption. Two mines in Alaska and six in Missouri accounted for 97 percent of domestic lead production in 2002. The United States also imports enough refined lead to satisfy almost 20 percent of domestic consumption. Other major producers or consumers of refined lead in the world are Australia, Canada, China, France, Germany, Italy, Japan and the United Kingdom.

Geotimes↗

Industrial diamond

Estimated 2011 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2011, natural industrial diamonds were produced in more than 20 countries, and synthetic industrial diamond was produced in at least 13 countries. About 98 percent of the combined natural and synthetic global output was produced in China, Ireland, Japan, Russia, South Africa and the United States. China is the world's leading producer of synthetic industrial diamond followed by Russia and the United States.

Mining Engineering↗

Mineral resource of the month: lead

The United States is a major producer and consumer of refined lead, representing almost one quarter of total world production and consumption. Two mines in Alaska and six in Missouri accounted for 97 percent of domestic lead production in 2002. The United States also imports enough refined lead to satisfy almost 20 percent of domestic consumption. Other major producers or consumers of refined lead in the world are Australia, Canada, China, France, Germany, Italy, Japan and the United Kingdom.

Geotimes↗

Mineral resource of the month: silver

Silver has been used for thousands of years as ornaments and utensils, for trade and as the basis of many monetary systems. The metal has played an important part in world history. Silver from the mines at Laurion, Greece, for example, financed the Greek victory over the Persians in 480 B.C. Silver from Potosi, Bolivia, helped Spain become a world power in the 16th and 17th centuries. And silver from the gold-silver ores at the Comstock Lode in Virginia City, Nev., helped keep the Union solvent during the Civil War.

Geotimes↗

Industrial diamond

Estimated 2012 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2012, natural industrial diamonds were produced in at least 20 countries, and synthetic industrial diamond was produced in at least 12 countries. About 99 percent of the combined natural and synthetic global output was produced in Belarus, China, Ireland, Japan, Russia, South Africa and the United States. During 2012, China was the world’s leading producer of synthetic industrial diamond followed by the United States and Russia. In 2012, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 103 million carats, valued at about $70.6 million. This was an estimated 43.7 million carats of synthetic diamond bort, grit, and dust and powder with a value of $14.5 million combined with an estimated 59.7 million carats of synthetic diamond stone with a value of $56.1 million. Also in 2012, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder. The United States government does not collect or maintain data for either domestic PCD producers or domestic chemical vapor deposition (CVD) diamond producers for quantity or value of annual production. Current trade and consumption quantity data are not available for PCD or for CVD diamond. For these reasons, PCD and CVD diamond are not included in the industrial diamond quantitative data reported here.

Mining Engineering↗

The effects of feral cats on insular wildlife: the Club-Med syndrome

Domestic cats have been introduced to many of the world‘s islands where they have been particularly devastating to insular wildlife which, in most cases, evolved in the absence of terrestrial predatory mammals and feline diseases. We review the effects of predation, feline diseases, and the life history characteristics of feral cats and their prey that have contributed to the extirpation and extinction of many insular vertebrate species. The protozoan Toxoplasma gondii is a persistent land-based zoonotic pathogen hosted by cats that is known to cause mortality in several insular bird species. It also enters marine environments in cat feces where it can cause the mortality of marine mammals. Feral cats remain widespread on islands throughout the world and are frequently subsidized in colonies which caretakers often assert have little negative effect on native wildlife. However, population genetics, home range, and movement studies all suggest that there are no locations on smaller islands where these cats cannot penetrate within two generations. While the details of past vertebrate extinctions were rarely documented during contemporary time, a strong line of evidence is emerging that the removal of feral cats from islands can rapidly facilitate the recolonization of extirpated species, particularly seabirds. Islands offer unique, mostly self-contained ecosystems in which to conduct controlled studies of the effects of feral cats on wildlife, having implications for continental systems. The response of terrestrial wildlife such as passerine birds, small mammals, and herptiles still needs more thorough long-term monitoring and documentation after the removal of feral cats.

Conference Paper↗

Preliminary results from the investigation of the Pymatuning earthquake of September 25, 1998

The Pymatuning earthquake occurred on Friday, September 25, 1998, at 19:52:52 Universal Coordinated Time (UTC), or 3:52:52 p.m. EDT, near Jamestown, Pa., at the southern end of the Pymatuning Reservoir, which straddles the Ohio-Pennsylvania border. The National Earthquake Information Center (NEIC) determined that the event had a magnitude of 5.2 mbLg (a magnitude scale used to measure the size of earthquakes that are regional distances away [100 to 1,000 km, or 60 to 600 mi]), an epicenter of 41.5°N latitude, 80.4°W longitude, and an estimated depth of 5 km (3 mi). One person was reported injured as a result of being thrown to the ground by the earthquake, and it caused minor damage to buildings and seriously disrupted many water wells in the GreenvilleJamestown, Pa., area. The earthquake was generally felt over an area of approximately 200,000 km 2 (77,230 mi 2 ) throughout northern Ohio, western Pennsylvania and New York, and much of southern Ontario, Canada (see map on back cover). It was also felt as far west as Illinois and Wisconsin, as far east as New Jersey, Connecticut, and the District of Columbia, and as far south as Kentucky and Virginia. During the aftershock field investigation that commenced within 12 hours of the main shock, a World Wide Web site, < http://groundmotion.cr.usgs.gov/pym/pym.htm >, was established from the field headquarters. The web site was used not only to transmit investigation results to the world in near real time but also to receive information from the local community as new earthquake effects were reported. As of March 1999, at least 11 aftershocks have occurred, the largest being a magnitude 2.3. The largest recent previous earthquake in the region was the northeastern Ohio (Leroy) earthquake of magnitude 5.0 that occurred on January 31, 1986, about 65 km (40 mi) west-northwest of the Pymatuning shock. This event was also felt by many of those who felt the Pymatuning earthquake. Similar to most of the seismicity east of the Rocky Mountains, earthquakes in the region are probably shallow (5 to 10 km, or 3 to 6 mi), and Seeber and Armbruster (1993) hypothesized that the earthquakes occurred along preexisting zones of weakness in Precambrian rocks. Wegweiser and others (1998) suggested that seismicity in northwestern Pennsylvania may be associated with the northwest-trending “cross-strike discontinuities” that are recognized in Paleozoic rocks and may represent reactivation of faults in the Precambrian basement. Using structure-contour maps constructed on the tops of lower Paleozoic strata, Alexandrowicz and Cole (1999) found evidence of preexisting northwest-striking faults in the epicentral region of the Pymatuning shock. The Harvard focal mechanism for the Pymatuning earthquake (a method used to infer the slip and orientation of the fault that generated an earthquake) indicates thrust faulting on a northwest striking plane, which is consistent with the regional northeast-southwest compressive stress regime observed in the area. Seeber and Armbruster (1993) plotted three prior earthquakes in the epicentral area having magnitudes greater than 3; two were instrumentally located near the Pymatuning earthquake, and the third event occurred 20 to 30 km (12 to 19 mi) to the northeast in 1852 (Figure 1).

Connecticut;District of Columbia;Illinois;Kentucky↗

Chasing lava: a geologist's adventures at the Hawaiian Volcano Observatory

A lively account of the three years (1969-1972) spent by geologist Wendell Duffield working at the Hawaiian Volcano Observatory at Kilauea, one of the world's more active volcanoes. Abundantly illustrated in b&w and color, with line drawings and maps, as well. Volcanologists and general readers alike will enjoy author Wendell Duffield's report from Kilauea--home of Pele, the goddess of fire and volcanoes. Duffield's narrative encompasses everything from the scientific (his discovery that the movements of cooled lava on a lava lake mimic the movements of the earth's crust, providing an accessible model for understanding plate tectonics) to the humorous (his dog's discovery of a snake on the supposedly snake-free island) to the life-threatening (a colleague's plunge into molten lava). This charming account of living and working at Kilauea, one of the world's most active volcanoes, is sure to be a delight.

Hawai'i↗

Avian disease assessment in seabirds and non-native passerines birds at Midway Atoll NWR

Midway Atoll in the Northwestern Hawaiian Islands supports the largest breeding colony of Laysan albatross ( Phoebastria immutabilis ) in the world and is a proposed site for the translocation of endangered Northwestern Hawaiian Island passerine birds such as the Nihoa finch ( Telespiza ultima ), Nihoa millerbird ( Acrocephalus familiaris kingi ), or Laysan finch ( Telespiza cantans ). On the main Hawaiian Islands, introduced mosquito-borne avian malaria ( Plasmodium relictum ) and avian pox ( Avipoxvirus ) have contributed to the extinction and decline of native Hawaiian avifauna. The mosquito vector ( Culex quinquefasciatus ) is present on Sand Island, Midway Atoll, where epizootics of Avipoxvirus have been reported among nestling Laysan albatross, black-footed albatross ( Phoebastria nigripes ), and red-tailed tropicbirds ( Phaethon rubricauda ) since 1963. Two introduced passerines, the common canary ( Serinus canaria ) and the common myna ( Acridotheres tristis ), are also present on Sand Island and may serve as reservoirs of mosquito-borne pathogens. Assessing disease prevalence and transmission potential at Midway Atoll National Wildlife Refuge (NWR) is a critical first step to translocation of Nihoa endemic passerines. In May 2010 and April 2012 we surveyed Midway Atoll NWR for mosquitoes and evidence of mosquito-borne disease. Although we did not observe active pox infections on albatross nestlings in May 2010, active infections were prevalent on albatross nestlings in April 2012. Presumptive diagnosis of Avipoxvirus was confirmed by PCR amplification of the Avipoxvirus 4b core protein gene from lesions collected from 10 albatross nestlings. Products were sequenced and compared to 4b core protein sequences from 28 Avipoxvirus isolates from the Hawaiian Islands and other parts of the world. Sequences from all Midway isolates were identical and formed a clade with other Avipoxvirus isolates from seabirds that was distinct from other Avipoxvirus isolates from the Hawaiian Islands. Tissue from three presumptive avian pox lesions from common canaries tested negative for Avipoxvirus . Blood samples from 124 canaries and 61 mynas tested negative for Plasmodium by one or more diagnostic tests based on microscopy, serology, or PCR diagnostics. Prevalence of Avipoxvirus infection was highest among albatross nestlings (94.6%) in the vicinity of the septic tanks where adult C. quinquefasciatus reached their highest densities, and data from all sites suggest a positive correlation between mosquito abundance and Avipoxvirus prevalence. Adult C. quinquefasciatus were also locally abundant around fishless, constructed wetlands. Since 1996, infrastructure removal and source reduction efforts by the refuge have greatly reduced the availability of underground and container habitats for larval mosquitoes on Sand Island. However, the creation of artificial wetlands and a central septic system on Sand Island has resulted in new, highly productive larval mosquito habitat for C. quinquefasciatus . Despite the presence of endemic Avipoxvirus in albatross nestlings and the introduction of mosquito vectors and two susceptible passerine species in the last century, we found no evidence of the avian malaria Plasmodium relictum or a passerine-infecting Avipoxvirus on Midway Atoll NWR that would interfere with the successful translocation of endemic Northwestern Hawaiian Island passerines. Without eradication of mosquitoes from Midway Atoll, however, periodic epizootics of Avipoxvirus among nestling seabirds will likely continue, and the introduction of malaria and passerine strains of Avipoxvirus from migratory birds will remain a long-term threat to passerine restoration programs.

Hawai'i↗

Global land information system (GLIS) access to worldwide Landsat data

The Landsat Technical Working Group (LTWG) and the Landsat Ground Station Operations Working Group (LGSOWG) have encouraged Landsat receiving stations around the world to share information about their data holdings through the exchange of metadata records. Receiving stations forward their metadata records to the U.S. Geological Survey's EROS Data Center (EDC) on a quarterly basis. The EDC maintains the records for each station, coordinates changes to the database, and provides metadata to the stations as requested. The result is a comprehensive international database listing most of the world's Landsat data acquisitions This exchange of information began in the early 1980's with the inclusion in the EDC database os scenes acquired by a receiving station in Italy. Through the years other stations have agreed to participate; currently ten of the seventeen stations actively share their metadata records. Coverage maps have been generated to depict the status of the database. The Worldwide Landsat database is also available though the Global Land Information System (GLIS).

Pecora 12 Symposium↗

Vision for a worldwide fluvial-sediment information network

The nations of the world suffer both from the deleterious effects of some natural and human-altered fluxes of fluvial sediment and a lack of consistent and reliable information on the temporal and spatial occurrence of fluvial sediments. Decades ago, this difficulty was unavoidable due to a lack of understanding of the magnitude and scope of environmental influences exerted by fluvial sediment coupled with a dearth of tools for monitoring and studying the data. Such is no longer the case. Fluvial sediment has a broad influence on the environment and humanity. Data needs that were once limited primarily to reservoir and channel maintenance now include issues associated with public water supply; contaminated sediment management; productivity of agricultural lands; stream restoration and watershed health; in-stream biotic stability; post-wildfire channel morphology; dam decommissioning, rehabilitation, or removal; and legal requirements for sediment management (Gray and Glysson, 2005). The adverse effects of poorly managed or unmanaged sediment movement related to these and other issues are well-known qualitatively, and in some cases quantitatively. For example, physical, chemical, and biological damages attributable to fluvial sediment in North America alone are now estimated to range between $20 billion and $50 billion annually (Pimental and others, 1995; Osterkamp and others, 1998; 2004). Capabilities for monitoring, analyzing, storing, and sharing fluvial-sediment data have been developed and, in many cases, are sufficiently mature for consideration for global utilization. Hence, there is not only a strong and expanding need for a global effort to gauge and understand fluvial-sediment characteristics and processes better, but the knowledge and tools to achieve these ends are largely available and ready for their applicability to be evaluated. Given the increasing importance of erosion and sediment processes for water-resources management, an International Sedimentation Initiative (ISI, 2007a), under the United Nations Educational, Scientific, and Cultural Organization&rsquo;s International Hydrologic Programme (IHP, 2007) was adopted in 2004. The ISI, the focus of which is on sustainable water-resources management on the global scale, features six major activities and projects, which are listed as part of the section entitled, &ldquo;Relation of the WoFSIN concept to the thrusts of the International Sedimentation Initiative,&rdquo; that precedes the &ldquo;Conclusions&rdquo; section of this paper. Based on the need for more, and more consistent and reliable fluvial-sediment information and on the existence of the ISI and other international and national sediment programs, we envision the need for a Worldwide Fluvial Sediment-Information Network (WoFSIN) with a focus on data acquisition, storage, and dissemination globally. Envisioned components of a WoFSIN, administered largely via the Internet and relying mostly on the benefits derived from existing resources and programs, follow that summary. The goal of the WoFSIN is to maximize the availability and usefulness of the world&rsquo;s historical and current fluvial-sediment and ancillary data through collaboration with existing programs so as to require few additional resources in the long-term. Thus, the WoFSIN concept was developed recognizing that informed resource management is predicated on the availability of adequate and reliable information. The WoFSIN is described in the ensuing sections in stand-alone fashion, followed by a section that describes the complementary aspects of the WoFSIN and the International Sediment Initiative. Thus, our first objective is to describe the fundamental components of a WoFSIN. Our second objective is to identify overlap or gaps between the WoFSIN and ISI concepts that might be useful in refining the ISI&rsquo;s ability to meet its global mission to develop decision support for sediment management at the global scale more fully, cost-effectively, and (or) with enhanced quality.

Conference Paper↗

Critical elements in Carlin, epithermal, and orogenic gold deposits

Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits. A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then captured in air pollution control devices.

Book chapter↗