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Ground water in the Mohall area, Bottineau and Renville Counties, North Dakota

The Mohall area includes about 120 square miles in Bottineau and Renville Counties in northwestern North Dakota. Mohall, whose 1950 population was 1,073, is the only town in the area. The area is part of the Drift Prairie section of the Central Lowland physiographic province. It is characterized by the gently undulating ground moraine plain which slopes regionally to the northeast. It is drained by several southeast-trending intermittent streams which run almost at right angles to the regional slope. The geologic formations in the Mohall area may be conveniently grouped into three units: the alluvium or alluvial deposits, which are found in the valleys of the intermittent streams, the till and associated glaciofluvial deposits, and the bedrock formations. Ground water of reasonably good quality is obtained in the area only from the alluvial deposits. Because of the limited areal extent of these deposits, only a small number of farms obtain water supplies from them. However, the municipal water supply of the town of Mohall is obtained from these deposits in Spring Coulee northeast of the town, and much water for rural domestic use is hauled from the Becker well southwest of the town, in Little Deep Creek. The principal source of recharge to the alluvial deposits is seepage during the spring runoff period. Natural discharge occurs by underflow down the stream valleys, by evaporation from open water and marshy areas and transpiration by plants. The coefficient of transmissibility of the alluvium, n the basis of short pumping tests on Mohan wells 3 and 4, is indicated to be about 6,000 gallons a day per foot at well 3 and about 20,000 gallons a day per foot at well 4. The specific yield was computed as 0.25 from the pumping test on well 3. No gravel of importance was en countered in the two cross sections that were drilled across Spring Coulee near the municipal wells, and the greatest thickness of satu rated alluvial deposits found was only about 10 feet. A Saturated thickness of 20 feet of sand and gravel was penetrated in test drilling along Cut Bank Creek. This is the greatest thickness of saturated alluvial deposits penetrated anywhere in the area. Ground water in storage in these alluvial deposits has been estimated to be about 150 million gallons per mile. These deposits are favorably situated to receive recharge, as Cut Bank Creek drains a rather large area and contains long stretches of open water perennially, Therefore, it is believed that the alluvial deposits of Cut Bank Creek offer the best promise for the development of moderately large perennial ground-water supplies for the present and probable future needs of the town of Mohall. Test drilling in West Cut Bank Creek and in Little Deep Creek did not reveal alluvial deposits of such character and saturated thickness as to be considered favorable for the development of moderate to large water supplies, though some of the material encountered should yield adequate quantities for farm supplies. The till with its associated glaciofluvial deposits is the surface formation in the area except where covered by the alluvial deposits in the stream valleys. In the Mohall areas, this formation is not an important aquifer and fewer than half a dozen wells are known to obtain water from it. The glaciofluvial deposits penetrated by the test holes are not considered adequate sources for permanent municipal or industrial supplies because they are likely to have small-areal extent and the overlying, relatively impermeable till makes seasonal recharge to them practically impossible. Test drilling in the Souris River Valley about 12 miles west of Mohall penetrated as mutt as 58 feet of fluvial sediments, but practi-cally all the material is clay and silt. No important aquifers were found there. At least 50 percent of all the farm water supplies in the area are obtained from wells in the bedrock formations, which probably consist of the Fox Hills sandstone, the Cannonball formation, and the Ludlow and Tongue Rtter members of the Fort Union formation. Underlying these formations is approximately 2,600 feet of Cretaceous shale, which'is not water bearing. Water from the "Dakota" sandstone (including the possible equivalent of the Fuson shale and Lakota sandstone) may be obtained at depths of about 3,200 to 3,300 feet. The "Dakota sandstone" probably would yield water in sufficient quantity for municipal and many industrial purposes in this areas but the water is likely to be too highly mineralized for most domestic uses. Jurassic formations underlie the Cretaceous formations in the area. They do not constitute aquifers of importance, and, any water found in them is likely to be too highly mineralized for most purposes. In the Mohall area, by far the most suitable water for general purposes is obtained from the shallow alluvial deposits in the stream valleys. Of the seven samples of this water water analyzed, the highest concentration of dissolved solids was 1,242 parts per million and the lowest, 317 parts. The iron content was higher than desirable in two samples but satisfactory in all the others. Total hardness ranged from 196 to 570, which is higher than desirable. Nitrate was present in all samples analyzed and was excessively high in two samples. Water samples for analysis were not obtained from the till and associated glaciofluvial deposits but the water from these aquifers is likely to be more highly mineralized than the water from the alluvial. deposits. The water from the upper part of the bedrock is highly mineralized, but its mineral content varies considerably. The chloride concentration of the samples analyzed ranges from 608 to 3,740 parts per million and the bicarbonate concentration ranges from 160 to 860 parts per million. The specific conductance ranges from 3,190 to 11,120 micromhos and may represent total mineralization on the order of 1,500 to more than 6,000 parts per million in the water with high chloride and bicarbonate content.

North Dakota↗

State summaries: Illinois

According to the United States Geological Survey (USGS), Illinois ranked third in the amount of crushed stone produced from underground mining operations. In 2004, Illinois produced more than 76.5 Mt of crushed stone and 38.7 Mt of sand-and-gravel. Preliminary data for 2005 showed an increase in the production of crushed stone and a slight decrease in the production of sand-and-gravel. The state remained 16th in total value of nonfuel mineral production. In decreasing order of value, the minerals produced included crushed stone, cement, construction sand and gravel, lime, clay, peat, tripoli, industrial sand, crushed sandstone and gemstone.

Mining Engineering↗

Mineral of the month: aggregates

Natural aggregates, consisting of crushed stone, and sand and gravel, are a major contributor to economic health, and have an amazing variety of uses. Aggregates are among the most abundant mineral resources and are major basic raw materials used by construction, agriculture and other industries that employ complex chemical and metallurgical processes.

Geotimes↗

Reconnaissance of the chemical quality of surface waters of the Neches River basin, Texas

The kinds and quantities of minerals dissolved in the surface water of the Neches River basin result from such environmental factors as geology, streamflow patterns and characteristics, and industrial influences. As a result of high rainfall in the basin, much of the readily soluble material has been leached from the surface rocks and soils. Consequently, the water in the streams is usually low in concentrations of dissolved minerals and meets the U.S. Public Health Service drinking-water standards. In most streams the concentration of dissolved solids is less than 250 ppm (parts per million). The Neches River drains an area of about 10,000 square miles in eastern Texas. From its source in southeast Van Zandt County the river flows in a general southeasterly direction and empties into Sabine Lake, an arm of the Gulf of Mexico. In the basin the climate ranges from moist subhumid to humid, and the average annual rainfall ranges from 46 inches is the northwest to more than 52 inches in the southeast. Annual runoff from the basin has averaged 11 inches; however, runoff rates vary widely from year to year. The yearly mean discharge of the Neches River at Evadale has ranged from 994 to 12,720 cubic feet per second. The rocks exposed in the Neches River basin are of the Quaternary and Tertiary Systems and range in age from Eocene to Recent. Throughout most of the basin the geologic formations dip generally south and southeast toward the gulf coast. The rate of dip is greater than that of the land surface; and as a result, the older formations crop out to the north of the younger formations. Water from the outcrop areas of the Wilcox Group and from the older formations of the Claiborne Group generally has dissolved-solids concentrations ranging from 100 to 250 ppm; water from the younger formations has concentrations less than 100 ppm. The northern half of the basin has soft water, with less than 60 ppm hardness. The southern half of .the basin has very soft water, usually with less than 30 ppm hardness. The chloride concentrations are less than 20 ppm in surface water in the southern half of the basin and usually range from 20 to 100 ppm in the northern half of the basin. Concentrations greater than 100 ppm are found only where pollution is occurring. The Neches River basin has an abundance of surface water, but uneven distribution of runoff makes storage projects necessary to provide dependable water supplies. The principal existing reservoirs, with the exception of Striker Creek Reservoir, contain water of excellent quality. Chemical-quality data for the Striker Creek drainage area indicate that its streams are affected by .the disposal of brines associated with oil production. Sam Rayburn Reservoir began impounding water in 1965. The water impounded should prove of acceptable quality for most uses, but municipal and industrial wastes released into the Angelina River near Lufkin may have a degrading effect on the quality of the water, especially during extended periods of low flows. Water available for storage at the many potential reservoir sites will be of good quality; but, if the proposed salt-water barrier is to impound acceptable water, the disposal of oilfield brine into Pine Island Bayou should be discontinued.

Water Supply Paper↗

The role of the U.S. Geological Survey in the lithium industry

The U.S. Geological Survey has responsibility in the U.S. Department of the Interior to assess the nation's energy and mineral resources. The evaluation of reserves and resources of a commodity such as lithium should be a continuing process in the light of advancing technology and ever-growing knowledge of its geologic occurrence and geochemical behavior. Although reserves of lithium vary with market demand because of the investment required to find, develop, and appraise an ore body, total resources are a function of the geologic occurrence and geochemical behavior of lithium. By studying known deposits and publishing data on their origin and occurrence, the U.S. Geological Survey can aid in the discovery of new deposits and improve the resource base. Resource data are used both by the government and the private sector. Government funding for research on energy-related technologies such as electric vehicle batteries and fusion power requires assurance that there will be enough lithium available in time for commercialization. Questions of availability for all mineral commodities must be answered by the U.S. Geological Survey so that intelligent decisions can be made.

Energy↗

Mineral resource of the month: wollastonite

When asked about wollastonite, most people respond “wollasta-what?” That’s because the wollastonite industry in the United States is relatively small and not highly publicized. Furthermore, the general public does not have any direct contact with wollastonite despite its use in many consumer products, ranging from car brakes to paint.

Geotimes↗

Geology and undiscovered resource assessment of the potash-bearing Central Asia Salt Basin, Turkmenistan, Uzbekistan, Tajikistan, and Afghanistan: Chapter AA in Global mineral resource assessment

Undiscovered potash resources in the Central Asia Salt Basin (CASB) of Turkmenistan, Uzbekistan, Tajikistan, and Afghanistan were assessed as part of a global mineral resource assessment led by the U.S. Geological Survey. The term “potash” refers to potassium-bearing, water-soluble salts derived from evaporite basins, where seawater dried up and precipitated various salt compounds; the word for the element “potassium” is derived from potash. Potash is produced worldwide at amounts exceeding 30 million metric tons per year, mostly for use in fertilizers. The term “potash” is used by industry to refer to potassium chloride, as well as potassium in sulfate, nitrate, and oxide forms. For the purposes of this assessment, the term “potash” refers to potassium ores and minerals and potash ore grades. Resource and production values are usually expressed by industry in terms of K 2 O (potassium oxide) or muriate of potash (KCl, potassium chloride). The CASB hosts significant discovered potash resources and originated in an inland sea during Late Jurassic time. Seawater flowed into the CASB, mostly from its extreme northwestern margin near the modern Caspian Sea, during several evaporation episodes that deposited at least five different packages of evaporites, with virtually all potash in the second and fourth packages. In this study, the CASB was subdivided into three tracts (permissive areas) for evaluation: the Amu Darya tract in the west, the Gissar tract in the center, and the Afghan-Tajik tract in the east. The Gissar and Amu Darya tracts were quantitatively assessed, whereas the Afghan‑Tajik tract was only qualitatively assessed because of the commonly extreme depth (as deep as 7 km) of the Jurassic salt, extensive deformation, and a lack of known potash deposits. Two approaches were used to estimate amounts of undiscovered potash in the CASB. Stratabound evaporite deposits in the Amu Darya tract were evaluated using an Adaptive Geometric Estimation (AGE) approach, which estimates in-place potash volumes and tonnages. The Gissar tract was evaluated by using the AGE approach for stratabound deposits and the three-part form of assessment of Singer and Menzie (2005) for discrete halokinetic deposits. In the three-part form of assessment, numbers of undiscovered deposits were estimated and combined with grade and tonnage models to probabilistically forecast the amount of undiscovered potash. The Amu Darya tract is estimated to contain 38 billion metric tons of undiscovered potash as K 2 O by using the AGE approach for stratabound deposits. The hybrid stratabound-halokinetic Gissar tract is estimated to contain between 1 and 16 billion metric tons of undiscovered potash as K 2 O. Chapter 1 of this report provides an overview of the history of the CASB and summarizes evaporite potash deposition, halokinesis, and dissolution processes that have affected the current distribution of potash-bearing salt in the CASB. Chapter 2 describes the Gissar tract, an uplifted region that contains a mix of stratabound and halokinetic potash deposits and all of the discovered and exploited potash deposits of the CASB. Chapter 3 describes the Amu Darya tract, where evaporite deposits remain flat-lying and undeformed since their original deposition. Chapter 4 describes the highly deformed and compressed Afghan-Tajik tract and what is known of the deeply-buried Jurassic salt. Chapter 5 describes the spatial databases included with this report, which contain a collection of CASB potash information. Appendixes A and B summarize descriptive models for stratabound and halokinetic potash-bearing salt deposits, respectively. Appendix C summarizes the AGE method used to evaluate the Gissar and Amu Darya tracts. Appendixes D and E contain grade and thickness data for the Gissar and Amu Darya tracts. Appendix F provides the SYSTAT script used to estimate undiscovered K2 O in a CASB tract. Appendix G provides a potash glossary, and appendix H provides biographies of assessment participants.

Scientific Investigations Report↗

Airborne geophysical efforts for critical mineral systems mapping in the southern Midcontinent, USA

The increasing global demand for critical minerals to support energy and technological advancement has accelerated exploration and research efforts for these essential resources. Since 2019, the United States Geological Survey (USGS) Earth Mapping Resources Initiative (EMRI) has worked to modernize geologic mapping of the Nation to better understand its critical mineral resources. To further this initiative, the USGS has flown a series of high-resolution airborne magnetic and radiometric surveys over large areas of the southern Midcontinent. The surveys cover known critical mineral deposits and areas with the potential to host additional critical minerals based on the presence of one or more overlapping mineral systems. One aspect of EMRI emphasizes close collaboration between the USGS and the Association of American State Geologists, as well as other government and industry partners to leverage geophysical, geological, and geochemical expertise on both regional and local scales. The EMRI high-resolution airborne survey data provide new insights into the geophysical framework of the southern Midcontinent and its critical mineral endowment. Additionally, discoveries made from the data have directed new studies for critical mineral exploration.

southern Midcontinent↗

Using U.S. Geological Survey data in material flow analysis: An introduction

A few sources of basic data on worldwide raw materials production and consumption exist that are independently developed and freely available to the public. This column is an introduction to the types of information available from the U.S. Geological Survey (USGS), and explains how the data are assembled. The kind of information prepared by the USGS is essential to U.S. materials flow studies because the data make it possible to conduct these studies within a global context. The data include primary and secondary (scrap) production, consumption and stocks (mostly limited to the United States unless calculated), trade (not readily available for all countries), and prices for more than 80 mineral commodities. Materials flow studies by USGS specialists using these data are continuing (http://minerals.usgs.gov/minerals/mflow/). Figure 1 shows from where the data are collected and where they are used. Minerals information was downloaded by users 5.8 million times from USGS minerals information Web pages in 2008.

Journal of Industrial Ecology↗

Determination of layer-charge characteristics of smectites

A new method for calculation of layer charge and charge distribution of smectites is proposed. The method is based on comparisons between X-ray diffraction (XRD) patterns of K-saturated, ethylene glycol-solvated, oriented samples and calculated XRD patterns for three-component, mixed-layer systems. For the calculated patterns it is assumed that the measured patterns can be modeled as random interstratifications of fully expanding 17.1 Å layers, partially expanding 13.5 Å layers and non-expanding 9.98 Å layers. The technique was tested using 29 well characterized smectites. According to their XRD patterns, smectites were classified as group 1 (low-charge smectites) and group 2 (high-charge smectites). The boundary between the two groups is at a layer charge of −0.46 equivalents per half unit-cell. Low-charge smectites are dominated by 17.1 Å layers, whereas high-charge smectites contain only 20% fully expandable layers on average. Smectite properties and industrial applications may be dictated by the proportion of 17.1 Å layers present. Non-expanding layers may control the behavior of smectites during weathering, facilitating the formation of illite layers after subsequent cycles of wetting and drying. The precision of the method is better than 3.5% at a layer charge of −0.50; therefore the method should be useful for basic research and for industrial purposes.

Clays and Clay Minerals↗

Barite in the United States, exclusive of Alaska and Hawaii

The mineral barite, barium sulfate, is the chief source of barium and its compounds needed for many industrial processes and products. Barite is found the world over and is abundant and widely distributed throughout the United States. The barite deposits of the United States (exclusive of Alaska and Hawaii) are shown on the accompanying map. The principal geologic type of deposit is indicated by the shape of symbol and the relative importance of the deposit is indicated by the size of symbol. This text lists localities by State, and index numbers are keyed to the map. Localities are distinguished by name of mine, prospect, or geographic area; their coordinates are given to the nearest minute of latitude and longitude. Geologic relations of each occurrence, if known, are summarized briefly. The text and map were compiled from published and unpublished information, and at least one reference is given for each locality, if reports have been published. The listings in some States are preceded by a principal reference which is a major source of information about deposits in those States.

Mineral Investigations Resource Map↗

Mineral precipitation and dissolution at two slag-disposal sites in northwestern Indiana, USA

Slag is a ubiquitous byproduct of the iron- and steel-refining industries. In northwestern Indiana and northeastern Illinois, slag has been deposited over more than 52 km2 of land surface. Despite the widespread use of slag for fill and construction purposes, little is known about its chemical effects on the environment. Two slagdisposal sites were examined in northwestern Indiana where slag was deposited over the native glacial deposits. At a third site, where slag was not present, background conditions were defined. Samples were collected from cores and drill cuttings and described with scanning electron microscopy and electron microprobe analysis. Ground-water samples were collected and used to assess thermodynamic equilibria between authigenic minerals and existing conditions. Differences in the mineralogy at background and slag-affected sites were apparent. Calcite, dolomite, gypsum, iron oxides, and clay minerals were abundant in native sediments immediately beneath the slag. Mineral features indicated that these minerals precipitated rapidly from slag drainage and co-precipitated minor amounts of non-calcium metals and trace elements. Quartz fragments immediately beneath the slag showed extensive pitting that was not apparent in sediments from the background site, indicating chemical weathering by the hyperalkaline slag drainage. The environmental impacts of slag-related mineral precipitation include disruption of natural ground-water flow patterns and bed-sediment armoring in adjacent surface-water systems. Dissolution of native quartz by the hyperalkaline drainage may cause instability in structures situated over slag fill or in roadways comprised of slag aggregates.

Indiana↗

Shift in Global Tantalum Mine Production, 2000–2014

Introduction Tantalum has a unique set of properties that make it useful in a number of diverse applications. The ability of the metal to store and release electrical energy makes it ideally suited for use in certain types of capacitors that are widely used in modern electronics. Approximately 60 percent of global tantalum consumption is in the electronics industry. The ductility and corrosion resistance of the metal lends itself to application in the chemical processing industry, and its high melting point and high strength retention at elevated temperatures make it an important component of super alloys used in aircraft engines. As a major industrialized nation, the United States is a leading consumer of tantalum and tantalum-containing products. Domestic deposits typically are of low grade, and no tantalum has been recovered from mining activities in the United States since 1959. Consequently, the United States is nearly completely reliant on imports to meet its domestic consumption of tantalum for economic and national security needs. The recovery of tantalum from mine production is economically viable in only a few countries. Although developed countries dominated tantalum mine production in the early 2000s, production today is dominated by countries in the Great Lakes Region of Africa. There is concern that the sales of minerals, including columbite-tantalite or “coltan,” a mineral from which tantalum is derived, have helped finance rebel groups accused of violating human rights as part of the continuing armed conflict in the Democratic Republic of the Congo (DRC) and neighboring countries. These accusations have prompted the passage of legislation in the United States to curb the procurement of these mineral commodities, referred to as “conflict minerals,” from the DRC. Specifically, section 1502 of the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act (Public Law 111–203, 124 Stat. 2213–2218) requires companies that source tantalum, tin, tungsten, and gold (3TG) to perform due diligence on their supply chains to determine if the materials they use originate from the DRC or adjoining countries (defined as sharing a border with the DRC). The DRC, Rwanda, and surrounding countries are not globally significant sources of tin, tungsten, or gold, accounting for only about 2 percent of the mined world supply for each of these elements. The region has, however, evolved to become the world’s largest producer of mined tantalum. A further complication of the production of tantalum stems from the opacity of the tantalum market. Unlike most base and precious metals, tantalum concentrates are not publicly traded through commodities exchanges but are bought and sold through networks of dealers and on contract between producers and consumers, some of whom may not provide accurate statistical data concerning the amounts, origins, and destination of the concentrates. Some price data can be found in trade journals or in other publications; however, there are no recognized official set exchange prices for either concentrate or tantalum metal. Because price is determined by negotiation between buyer and seller, published prices for concentrate are probably not representative of global prices paid for concentrate. The development of a mine-to-market supply-chain analysis is complicated and difficult because many of the industry participants that produce, trade, and consume tantalum do not publish statistical information, contracts are long term between miners and buyers, and much of the industry is vertically integrated. As a result of these and other considerations, tantalum is considered by many to be a “critical” commodity. This fact sheet identifies and addresses the major geographic shifts in the source of mine production of tantalum which have occurred over the past 15 years, some of the factors that drove this shift, and some of the related consequences. One of the activities of the U.S. Geological Survey National Minerals Information Center (USGS-NMIC) is to analyze global supply chains and characterize major components of mineral and material flows from ore extraction through processing to first tier products. These analyses support the core mission of the USGS-NMIC as the Federal entity responsible for the collection, analysis, and dissemination of objective, unbiased, factual information on minerals essential to the U.S. economy and national security.

Fact Sheet↗

Tin and related elements in sediments and beach sands from Afghanistan, Iran, and Turkey

Sixty samples of sediments from stream beds, outwash plains, and beaches were collected in Afghanistan, Iran, and Turkey by Fred L. Klinger, U.S. Bureau of Mines, as part of the field work undertaken by the National Geographic-Smithsonian Pyrotechnological Expedition of 1968. Facilities for the analysis of the samples for tin and other metals were not immediately available, but in 1973 arrangements were made for analyses to be made on a time-permitting basis in the U.S. Geological Survey. The original purpose in collecting the samples was to determine whether tin was present in amounts indicative of sources for tin ores used in antiquity for the manufacture of bronze. The results of the analyses not only permitted an evaluation of the potential for tin in the localities sampled, but also afforded chemical and mineralogical data that were interpretable in the context of regional potential for other elements of current industrial use. These include gold, base metals, ferro-alloy metals, beryllium, rare earths, and barium. The original 60 samples of sand were sieved to make three size fraction (>0.707 mm, <O.707->O.177 mm, and <0.177 mm) for spectrographic and chemical analysis. Splits of these fractions were used for replicate analyses to permit evaluation of the precision of the analytical procedures. Further splitting of the <0.707->0.177 mm sand gave fractions from each sample that were separated in bromoform. Concentrates from the heavy-liquid separations were divided magnetically into six parts from most magnetic to least magnetic. These concentrates were analyzed spectrographically. The precision of the spectrographic analyses is well within the limits of precision expected from semiquantitative procedures. Such precision allows semiquantitative spectrographic procedures to be used with confidence as a valuable tool for reconnaissance investigations in which multi-element analyses are necessary. The analyses of the various fractions of sediments and sediment concentrates indicate the sample media in which an element was most likely to occur. Tin exhibited no preferential concentration into any particular medium. However, many elements with which tin is associated, and other elements of industrial use, do concentrate into one or more of the sample media. This indication of a preferred medium permits interpretation of the analyses as to the best sample medium for a particular element in the environment of western Asia. Cassiterite and/or tin were detected in many samples from Afghanistan, Iran, and Turkey, but in most of the samples the tin was present in normal crustal abundance. Sixteen samples, including seven from Afghanistan, eight from Iran, and one from Turkey contain unusually large amounts of tin. The most notable areas of anomalous tin are near Mirzaka, Qala-i-Asad, and Shah Agha in Afghanistan; near Meshed, Shir Kuh, Natanz, Nodus, and Talmesi in Iran; and on the shore of the Balck Sea just west of Trabzon in Turkey. Even in these localities the tin appears to be a minor element associated with other ores. The most common association of tin is with copper at known mineralized areas. This relation may have historical significance in the context of the development of bronze. The results of the analyses provided geochemical data on the distribution of other elements of industrial use and clearly identified nine of the ten known mineral deposits represented by the samples. The known metallization at the reported deposits may be only a part of more complex groups of metals. In Afghanistan an array of anomalous elements at the known gold placers around Mirzaka and along the Anguri River signals the presence of complex ore deposits. These elements are silver, arsenic, gold, bismuth, cadmium, copper, mercury, indium, molybdenum, lead, antimony, tin, thallium, tungsten, and zinc. They may indicate a Carlin-type gold deposit in which the wall-rocks are enriched in micron-sized particles of gold. Other localities in Afghanistan signalled by the results of the analyses to be anomalous and to merit further geochemical exploration are: (1) a reach of the Panjshir River for beryllium, lead, zinc, chromium and nickel; (2) the area near Bamian for beryllium; (3) the Siakhak village area for gold and copper; (4) around Qala-i-Asad and Shah Agha for lead, zinc, gold, and tungsten. Some attention to the distribution of monazite around Siakhak, Shahjui, Qala-i-Asad, and Shah Agha is justified to determine if this ore mineral for the rare earths and thorium is enriched over its normally expectable trace as an accessory mineral in granitic rocks, pelitic schists, and gneisses. In Iran, the pluton of granodiorite porphyry near Sar Cheshmeh, an area where a huge porphyry copper deposit was being investigated by the Geological Survey of Iran when the present samples were collected in 1968, shows as a strong geochemical anomaly for copper and molybdenum. The granitic area near Meshed is geochemically enriched persistently in beryllium, tin, and barium, and locally in gold, lanthanum, niobium, yttrium, and other elements. This area deserves a thorough regional geochemical survey for beryl and nonberyl sources of beryllium, for fluorite, and for the ores of niobium, tin, barium, the rare earths, and thorium. Other localities in Iran that merit geochemical exploration on the basis of these data are: ;1) the areas between Tabas and Deyhuk, east of Naiband, and south of Naiband for barium and zinc; (2) a locality about midway between Kerman and Sirdjan for barium, lanthanum, strontium, and zinc; (4) the Meskani copper mine area for mercury, lead, and nickel as well as copper; (5) the Talmesi copper mine area for such other elements as barium, cobalt, mercury, strontium, and zinc; (6) a small pluton of granodiorite north of Natanz for tungsten and base metals; (7) the vicinity of Zendjan for auriferous polymetallic sufide deposits; (8) gold in the gorge 15 km east of Miyaneh; and (9) the area near Nodus for gold, base metals, molybdenum, and niobium, and possibly uranium. The Harsit River basin in Turkey appears to be a suitable target for geochemical exploration for gold and low-temperature hydrothermal deposits of base metals, barium, and mercury.

Open-File Report↗

Nitrogen deposition weakens soil carbon control of nitrogen dynamics across the contiguous United States

Anthropogenic nitrogen (N) deposition is unequally distributed across space and time, with inputs to terrestrial ecosystems impacted by industry regulations and variations in human activity. Soil carbon (C) content normally controls the fraction of mineralized N that is nitrified ( ƒ nitrified ), affecting N bioavailability for plants and microbes. However, it is unknown whether N deposition has modified the relationships among soil C, net N mineralization, and net nitrification. To test whether N deposition alters the relationship between soil C and net N transformations, we collected soils from coniferous and deciduous forests, grasslands, and residential yards in 14 regions across the contiguous United States that vary in N deposition rates. We quantified rates of net nitrification and N mineralization, soil chemistry (soil C, N, and pH), and microbial biomass and function (as beta-glucosidase (BG) and N -acetylglucosaminidase (NAG) activity) across these regions. Following expectations, soil C was a driver of ƒ nitrified across regions, whereby increasing soil C resulted in a decline in net nitrification and ƒ nitrified . The ƒ nitrified value increased with lower microbial enzymatic investment in N acquisition (increasing BG:NAG ratio) and lower active microbial biomass, providing some evidence that heterotrophic microbial N demand controls the ammonium pool for nitrifiers. However, higher total N deposition increased ƒ nitrified , including for high soil C sites predicted to have low ƒ nitrified , which decreased the role of soil C as a predictor of ƒ nitrified . Notably, the drop in contemporary atmospheric N deposition rates during the 2020 COVID-19 pandemic did not weaken the effect of N deposition on relationships between soil C and ƒ nitrified . Our results suggest that N deposition can disrupt the relationship between soil C and net N transformations, with this change potentially explained by weaker microbial competition for N. Therefore, past N inputs and soil C should be used together to predict N dynamics across terrestrial ecosystems.

contiguous United States↗

Manganese: it turns iron into steel (and does so much more)

Manganese is a common ferrous metal with atomic weight of 25 and the chemical symbol Mn. It constitutes roughly 0.1 percent of the Earth’s crust, making it the 12th most abundant element. Its early uses were limited largely to pigments and oxidants in chemical processes and experiments, but the significance of manganese to human societies exploded with the development of modern steelmaking technology in the 1860s. U.S consumption of manganese is about 500,000 metric tons each year, predominantly by the steel industry. Because manganese is essential and irreplaceable in steelmaking and its global mining industry is dominated by just a few nations, it is considered one of the most critical mineral commodities for the United States.

Fact Sheet↗

Metalliferous mineral resource potential of the Seward and Blying Sound quadrangles, southern Alaska

This mineral potential map is the final report in a series of publications that makes up a folio on the Seward and Blying Sound quadrangles of southern Alaska. It draws on data largely presented in previous publications of the folio. The studies were undertaken as part of the Alaska Mineral Resource Assessment Program (AMRAP), a program designed to provide information for Federal, State, local, and industry decisions concerning the future uses of Alaskan lands and resources.

Alaska↗

Reconnaissance geology of the Wadi Amq Quadrangle, sheet 18/41 C, Kingdom of Saudi Arabia

The Wadi Amq quadrangle (sheet 18/41 C) lies between lat 18?00' and 18?30' N. and long 41?00' and 41?30' E. and encompasses an area of 2,937 km2, of which only about 150 km2 is land; the remainder is covered by the Red Sea. The only geologic formations exposed in the quadrangle are Quaternary volcanic rocks and surficial deposits. Most of the volcanic rocks are basalt that was extruded during a continuation of the opening of the Red Sea rift. The Quaternary surficial deposits include those of shallow bank and coral reefs, carbonate sand, sabkhahs, pediment and plains, and alluvial sand and gravel. The coral reefs could possibly provide raw material for a cement industry if required, and the sabkhahs might yield useful salts; otherwise the quadrangle has no economic mineral potential.

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