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USGS2021

Stratigraphic cross sections of the Mowry Shale and associated strata in the Wind River Basin, Wyoming

The Wind River Basin in Wyoming is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny in the latest Cretaceous through the early Eocene. The basin (bounded by the Washakie, Owl Creek, and Bighorn uplifts on the north, the Casper arch on the east, the Granite Mountains uplift on the south, and Wind River uplift on the west) encompasses about 7,400 square miles in central Wyoming. The two stratigraphic cross sections presented in this report were constructed as part of a project carried out by the U.S. Geological Survey to characterize and evaluate the undiscovered continuous (unconventional) oil and gas resources of the Mowry Shale in the Wind River Basin in central Wyoming. The purpose of the cross sections is to show the stratigraphic relationship of the Mowry Shale and associated Lower and lowermost Upper Cretaceous strata in the Wind River Basin. These two cross sections were constructed using borehole geophysical logs from 41 wells drilled for oil and gas exploration and production, and one research well that was cored and logged by the U.S. Geological Survey. Both lines originate at Sheldon Dome in the northwestern part of the basin and end near Bates Creek in the extreme southeastern part of the basin. The stratigraphic interval extends from the uppermost part of the Upper Jurassic Morrison Formation to the basal part of the Upper Cretaceous Frontier Formation. The datum is the top of the Clay Spur Bentonite Bed, a distinctive bed at the top of the Upper Cretaceous Mowry Shale. A gamma ray and (or) spontaneous potential log was used in combination with a resistivity log to identify and correlate units.

Wyoming↗

USGS2017

Generalized hydrogeologic framework and groundwater budget for a groundwater availability study for the glacial aquifer system of the United States

The glacial aquifer system groundwater availability study seeks to quantify (1) the status of groundwater resources in the glacial aquifer system, (2) how these resources have changed over time, and (3) likely system response to future changes in anthropogenic and environmental conditions. The glacial aquifer system extends from Maine to Alaska, although the focus of this report is the part of the system in the conterminous United States east of the Rocky Mountains. The glacial sand and gravel principal aquifer is the largest source of public and self-supplied industrial supply for any principal aquifer and also is an important source for irrigation supply. Despite its importance for water supply, water levels in the glacial aquifer system are generally stable varying with climate and only locally from pumping. The hydrogeologic framework developed for this study includes the information from waterwell records and classification of material types from surficial geologic maps into likely aquifers dominated by sand and gravel deposits. Generalized groundwater budgets across the study area highlight the variation in recharge and discharge primarily driven by climate.

Glacial Aquifer System↗

USGS1936

Degree of reduction of sediments in the East Texas basin as an index of source beds

The research project on source beds, sponsored jointly by the U. S. Geological Survey and the American Petroleum Institute, for the past 18 months has undertaken a study of the degree of reduction as an index of source beds. As indicated in a previous paper on this same subject presented before the Institute at the Los Angeles meeting, this index has to be tested in several petroliferous provinces before its value can be definitely ascertained. Thus far it has been found to prevail in two petroliferous regions, viz., the Rocky Mountains and the Mid Continent; as sediments regarded as source beds in these areas have been observed commonly to have a relatively high degree of reduction. In this paper this relationship is extended to the East Texas basin, as most of the sediments associated with oil zones there in general have been found to have a comparatively high degree of reduction. The relationship, as in other areas, however, has not been observed to hold invariably. Each succeeding area in which the relationship is found to prevail strengthens the probability that it is real and not anomalous. If it is found to hold in the three remaining petroliferous provinces that are now being studied, viz., California, Gulf Coast, and Appalachian, the probability will be strong that it is a true relationship, with the result that it can be recommended to geologists for consideration in prospecting for oil.

Conference Paper↗

USGS2006

The fifth International Geological Congress, Washington, 1891

The 5th International Geological Congress (IGC), the initial meeting in North America, was the first of the three IGCs that have been held in the United States of America (USA). Of the 538 registrants alive when the 5th IGC convened in Washington, 251 persons, representing fifteen countries, actually attended the meeting. These participants included 173 people from the USA, of whom forty-two represented the US Geological Survey (USGS). Fourteen of the US State geological surveys sent representatives to Washington. Eight participants came from other countries in the Western Hemisphere - Canada (3), Chile (1), Mexico (3), and Peru (1). The sixty-six European geologists and naturalists at the 5th IGC represented Austro-Hungary (3), Belgium (3), Britain (12), France (7), Germany (23), Norway (1), Romania (3), Russia (8), Sweden (4), and Switzerland (2). The USGS and the Columbian College (now the George Washington University) acted as the principal hosts. The American Association for the Advancement of Science and then the Geological Society of America (GSA) met in the Capital immediately before the Congress convened (26 August-1 September 1891). The 5th IGC's formal discussions treated the genetic classification of Pleistocene rocks, the chronological correlation of clastic rocks, and the international standardization of colors, symbols, and names used on geologic maps. The third of those topics continued key debates at the 1st through 4th IGCs. The GSA, the Korean Embassy, the Smithsonian Institution's US National Museum, the USGS, and one of the two Secretaries-General hosted evening receptions. Field excursions examined Paleozoic exposures in New York (18-25 August), Cretaceous-Pleistocene localities along the Potomac River south of Washington (30 August), and classic Precambrian-Pleistocene sequences and structures in the Great Plains, Yellowstone, Rocky Mountains, and Great Basin (2-26 September), with optional trips to the Grand Canyon (19-28 September) and Lake Superior (23 September-2 October). The single-volume report of the 5th IGC was published in Washington in 1893.

Conference Paper↗

USGS2000

Research, methodology, and applications of probabilistic seismic-hazard mapping of the Central and Eastern United States; minutes of a workshop on June 13-14, 2000, at Saint Louis University

The U.S. Geological Survey (USGS) is updating and revising its 1996 national seismic-hazard maps for release in 2001. Part of this process is the convening of four regional workshops with earth scientists and other users of the maps. The second of these workshops was sponsored by the USGS and the Mid-America Earthquake Center, and was hosted by Saint Louis University on June 13-14, 2000. The workshop concentrated on the central and eastern U.S. (CEUS) east of the Rocky Mountains. The tasks of the workshop were to (1) evaluate new research findings that are relevant to seismic hazard mapping, (2) discuss modifications in the inputs and methodology used in the national maps, (3) discuss concerns by engineers and other users about the scientific input to the maps and the use of the hazard maps in building codes, and (4) identify needed research in the CEUS that can improve the seismic hazard maps and reduce their uncertainties. These minutes summarize the workshop discussions. This is not a transcript; some individual remarks and short discussions of side issues and logistics were omitted. Named speakers were sent a draft of the minutes with a request for corrections of any errors in remarks attributed to them. Nine people returned corrections, amplifications, or approvals of their remarks as reported. The rest of this document consists of the meeting agenda, discussion summaries, and a list of the 60 attendees.

Open-File Report↗

USGS2023

The 3D Elevation Program—Supporting Montana’s economy

Introduction Montana, America’s fourth largest State with an area of 147,040 square miles, is defined by its diverse terrain. The western two-fifths of the State falls within the Rocky Mountains and the eastern three-fifths is in the Great Plains. Because of its location along the Continental Divide, the rivers in Montana drain into either the Pacific Ocean or the Gulf of Mexico. Montana is often called the Treasure State due to its mineral wealth, which includes oil, gas, and coal, but the State’s primary economic activity is agriculture. Other economic activities include natural resources conservation, water supply and quality, infrastructure and construction management, flood risk management, and geologic resource assessment and hazard mitigation. Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features.

Montana↗

USGS1965

Geology of the Coeur d'Alene district, Shoshone County, Idaho

The Coeur d'Alene district, near the base of the northern panhandle of Idaho, is one of the world's larger lead- zinc and silver-producing areas. The greater part of the dis~rict i~ included within five map areas, from east to west the Pottsville, Mullan, Wallace, Kellogg, and Smelterville, which were geologically mapped during this study. These quadrangles encompass an area about 26 miles long in an east-west direction and about 9 miles wide. The district lies wholly within the Coeur d'Alene Mountains, the part of the Bitterroot Range that is drained by the Coeur d'Alene River. The Bitterroot Range is a rugged, deeply dissected mountain mass which extends on both sides of the Idaho-Montana boundary for more than 200 miles and is a part of the Northern Rocky Mountains; within the district the range has a relief of 3,000-4,000 feet. The westward-flowing South Fork of the Coeur d'Alene River bisects the district, and roads along this river and its major tributaries generally provide easy access to the communities and many mines.

Idaho↗

USGS2022

Colorado and Landsat

Colorado’s geography seems designed to impress. Although the Rocky Mountains takes up only one-half of the State, more than 50 of its peaks rise at least 14,000 feet above sea level—far more “fourteeners” than any other State. Many of these mountains receive hundreds of inches of snow annually. The Rocky Mountains provide the Continental Divide, or watershed boundary, for North America. Three of the United States’ seven longest rivers originate in Colorado’s mountains: the Rio Grande, the Colorado, and the Arkansas Rivers. The mountains are also home to 11 national forests. Residents and tourists find many ways to appreciate the stunning views, from hiking and skiing to camping and birdwatching, in ecosystems that also include grasslands and shrublands.

Colorado↗

USGS1987

Coal deposits of the United States

The coal fields of the Unites States can be divided into six major provinces. The Appalachian and Interior Provinces contain dominantly bituminous coal in strata of Pennsylvanian age. The coal seams are relatively thin and are mined both by surface and underground methods. Sulfyur content is low to moderate in the Appalachian Province, generally high in the Interior province. The Gulf Coastal Plain Province, in Texas and neighboring states, contains lignite of Eocene age. The seams are 3–25 ft (0.9–7.5 m) thick and are minded in large open pits. The Northern Great Plains Province has lignite and subbituminous coal of Cretaceous, Paleocene and Eocene age. The coal, largely very low in sulfur, occurs in beds up to 100 ft (30 m) thick and is strip-mined. The Rocky Mountain Province contains a great variety of coal deposits in numerous separate intermontane basins. Most of it is low-sulfur subbituminous to bituminous coal iof Creatceous and early Tertiary age. The seams range from a few feet to over 100 ft (30 m) thick. Strip-mining dominates but underground mines are important in Utah and Colorado. The Pacific Coast Province, which includes Alaska, contains enormous cola resources but has seen little mining. The coal is highly diverse in physical character and geologic setting.

International Journal of Coal Geology↗

USGS2005

Arsenic in ground water of the United States: occurrence and geochemistry

Concentrations of naturally occurring arsenic in ground water vary regionally due to a combination of climate and geology. Although slightly less than half of 30,000 arsenic analyses of ground water in the United States were 1 μg/L, about 10% exceeded 10 μg/L. At a broad regional scale, arsenic concentrations exceeding 10 μg/L appear to be more frequently observed in the western United States than in the eastern half. Arsenic concentrations in ground water of the Appalachian Highlands and the Atlantic Plain generally are very low ( 1 μg/L). Concentrations are somewhat greater in the Interior Plains and the Rocky Mountain System. Investigations of ground water in New England, Michigan, Minnesota, South Dakota, Oklahoma, and Wisconsin within the last decade suggest that arsenic concentrations exceeding 10 μg/L are more widespread and common than previously recognized. Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 μg/L in ground water. This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i.e., petroleum products) organic carbon. Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the western United States. Sulfide minerals are both a source and sink for arsenic. Geothermal water and high evaporation rates also are associated with arsenic concentrations 10g/L in ground and surface water, particularly in the west. Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 µg/L a ground water. This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i.e., petroleum products) organic carbon. Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the Western United States. Sulfide minerals are both a source and sink for arsenic. Geothermal water and high evaporation rates also are associated with arsenic concentrations ≥ 10g/L in ground and surface water, particularly in the west.

Ground Water↗

USGS2009

Greater Platte River Basins - Science to sustain ecosystems and communities

The Greater Platte River Basins (GPRB), located in the heartland of the United States, provides a collaborative opportunity for the U.S. Geological Survey (USGS) and its partners to understand the sustainability of natural and managed ecosystems under changing climate and resource requirements.The Greater Platte River Basins, an area of about 140,000 square miles, sustains thousands of acres of lakes and wetlands, which provide a staging and resting area for the North American Central Flyway. Part of the GPRB is within the U.S. Corn Belt, one of the most productive agricultural ecosystems on Earth. Changes in water and land use, changing patterns of snowmelt in the Rocky Mountains, drought, and increasing demands for irrigation have reduced flows in the Platte River. These changes raise questions about the sustainability of the region for both wildlife and agriculture.The USGS and partners are developing a science strategy that will help natural-resource managers address and balance the needs of this region.

Fact Sheet↗

USGS1970

Palynology of the Cretaceous-Tertiary boundary in the northern Rocky Mountain and Mississippi Embayment regions

In both the Rocky Mountain and the Mississippi Embayment regions it is often difficult to distinguish Upper Cretaceous from lower Tertiary rocks on the basis of physical characteristics; the transition can be recognized with relative ease, however, on the basis of abrupt qualitative changes in plant microfossils. Many Cretaceous species vanish and new species appear in the Paleocene. In both regions the Paleocene yields fewer species than does the underlying Cretaceous. A pronounced difference exists between the Late Cretaceous pollen and spore floras of the two regions. The spore-pollen assemblage from the Rocky Mountains is partially characterized by the presence of Aquilapollenites, Proteacidites, Wodehouseia, and an unnamed species of Tricolpites. These taxa are not found in the Late Cretaceous of the Mississippi Embayment region. The embayment region yields Rugubivesiculites, an unnamed species of Araucariacites, and several genera belonging to the Normapolles group that are not found in the Rocky Mountain region. The Mississippi Embayment Cretaceous and Paleocene pollen floras show greater similarities to pollen floras from Europe than to those from the northern Rocky Mountains. The Rocky Mountain pollen floras exhibit closer similarities to the Alaskan and Siberian floras. It is suggested that the floral dissimilarity between the Mississippi Embayment and the northern Rocky Mountain regions may be accounted for by the separation of the Rocky Mountain province from the Mississippi Embayment province during Late Cretaceous time by the great north-trending Cretaceous epeiric sea. It is further suggested that the floral changes across the Cretaceous-Tertiary transition may have been caused by slight climatic changes brought about by uplift or by withdrawal of the tempering influence of the epeiric sea.

Kentucky, Mississippi, Missouri, Montana, Tennesse↗

USGS1996

Preliminary investigation of the distribution and resources of coal in the Kaiparowits Plateau, southern Utah

This report on the coal resources of the Kaiparowits Plateau, Utah is a contribution to the U.S. Geological Survey's (USGS) 'National Coal Resource Assessment' (NCRA), a five year effort to identify and characterize the coal beds and coal zones that could potentially provide the fuel for the Nation's coal-derived energy during the first quarter of the twenty-first century. For purposes of the NCRA study, the Nation is divided into regions. Teams of geoscientists, knowledgeable about each region, are developing the data bases and assessing the coal within each region. The five major coal-producing regions of the United States under investigation are: (1) the Appalachian Basin; (2) the Illinois Basin; (3) the Gulf of Mexico Coastal Plain; (4) the Powder River Basin and the Northern Great Plains; and (5) the Rocky Mountains and the Colorado Plateau. Six areas containing coal deposits in the Rocky Mountain and Colorado Plateau Region have been designated as high priority because of their potential for development. This report on the coal resources of the Kaiparowits Plateau is the first of the six to be completed. The coal quantities reported in this study are entirely 'resources' and represent, as accurately as the data allow, all the coal in the ground in beds greater than one foot thick. These resources are qualified and subdivided by thickness of coal beds, depth to the coal, distance from known data points, and inclination (dip) of the beds. The USGS has not attempted to estimate coal 'reserves' for this region. Reserves are that subset of the resource that could be economically produced at the present time. The coal resources are differentiated into 'identified' and 'hypothetical' following the standard classification system of the USGS (Wood and others, 1983). Identified resources are those within three miles of a measured thickness value, and hypothetical resources are further than three miles from a data point. Coal beds in the Kaiparowits Plateau are laterally discontinuous relative to many other coal bearing regions of the United States. That is, they end more abruptly and are more likely to fragment or split into thinner beds. Because of these characteristics, the data from approximately 160 drill holes and 40 measured sections available for use in this study are not sufficient to determine what proportion of the resources is technologically and economically recoverable. The Kaiparowits Plateau contains an original resource of 62 billion short tons of coal in the ground. Original resource is defined to include all coal beds greater than one foot thick in the area studied. None of the resource is recoverable by surface mining. However, the total resource figure must be regarded with caution because it does not reflect geologic, technological, land-use, and environmental restrictions that may affect the availability and the recoverability of the coal. At least 32 billion tons of coal are unlikely to be mined in the foreseeable future because the coal beds are either too deep, too thin to mine, inclined at more than 12?, or in beds that are too thick to be completely recovered in underground mining. The estimated balance of 30 billion tons of coal resources does not reflect land use or environmental restrictions, does not account for coal that would be bypassed due to mining of adjacent coal beds, does not consider the amount of coal that must remain in the ground for roof support, and does not take into consideration the continuity of beds for mining. Although all of these factors will reduce the amount of coal that could be recovered, there is not sufficient data available to estimate recoverable coal resources. For purposes of comparison, studies of coal resources in the eastern United States have determined that less than 10 percent of the original coal resource, in the areas studied, could be mined economically at today's prices (Rohrbacher and others, 1994).

Open-File Report↗

USGS2018

Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado

The geologic map of the San Antonio Mountain area in northern New Mexico and southern Colorado is located along the west-central part of the San Luis Valley. The San Luis Valley is the geomorphic expression of the San Luis Basin, an extensional basin associated with the northern Rio Grande rift. Deposits within the map area record volcanic, sedimentary, and tectonic processes over the last ~33 million years. Oldest exposed deposits include Oligocene volcanic rocks associated with the southeast San Juan Mountains locus of volcanism within the Southern Rocky Mountains volcanic field. Overlying deposits of the Southern Rocky Mountains volcanic field are volcaniclastic sedimentary rocks interbedded with predominantly basaltic lava flows of Oligocene to Miocene age. Basalt to rhyolite volcanic rocks of the Pliocene to Pleistocene Taos Plateau volcanic field unconformably overlie Oligocene to Miocene volcanic and sedimentary deposits. Superposed on the Tertiary deposits are Pleistocene to Holocene alluvial and colluvial deposits. North- to northwest-trending faults displace rocks within the map area. Magnitude of deformation is broadly correlative with age of the deposits inasmuch as Oligocene to Miocene rocks display a greater degree of fault displacement and east tilting than Pliocene volcanic rocks. Within the map area, faults displace Oligocene to Miocene deposits 10–30 meters with generally down-to-west offset, and the units dip eastward 3–7 degrees. Pliocene volcanic rocks exhibit shallower eastward dips inferred primarily from the slope of upper lava flow surfaces that dip eastward from 1–3 degrees and lava flows are generally displaced less than 5 meters.

Colorado, New Mexico↗

USGS1986

Mines and prospects of the Butte 1° x 2° Quadrangle, Montana

The Butte quadrangle, in the Northern Rocky Mountains of southwestern Montana, has had a long, productive, and colorful mining history. Butte, the city from which the quadrangle takes its name, is located in the most famous mining district of the quadrangle. This district, the Butte or Summit Valley district, has been described as the "richest hill on earth" and is one of the richest and most productive mining districts of the world. The quantity of metals produced from this district alone are far greater than the combined total of all commodities from all other mining districts of the quadrangle. However, many districts other than Butte have had significant production as compared to other mining districts of the Northern Rocky Mountains. The dollar value of production from the Butte district is more than $6 billion (Miller, 1973) and that of the combined total of production from the other districts in the quadrangle is more than $400 million. These values are based on actual metal prices at the time of production. The totals would be many times larger if converted to present day commodity prices. Mineral occurrence data for a total of 1111 mines, prospects, and mineral occurrences have been compiled for the Butte quadrangle. These mineralized sites are found throughout the quadrangle but most are concentrated in the major mining districts; 78 percent are clustered in 46 established mining districts and the remaining 22 percent are more widely scattered in 24 geographic areas (fig. 1). Only small areas of the quadrangle lack significant mines, prospects, or mineral occurrences. The locations of mines and prospects are shown on maps (pl. 1 and 2) and a brief description of each site is given in a table arranged by mining district or geographic area (table 1) (all tables are at end of report). This table gives a brief description of each district or area and details of each site within the district or area including site number, name and alternate name(s), location by latitude and longitude, commodities present, description of the site, and sources of data. Data for this report come from the U.S. Geological Survey Mineral Resource Data System (MRDS; this was formerly known as the Computerized Resource Information Bank (CRIB)), from many published and unpublished sources, and from geologic field work. The Butte quadrangle is in southwestern Montana and is bounded by latitudes 46° and 47° N. and longitudes 112° and 114° W. The city of Butte is near the southern edge and in the southeastern corner of the quadrangle. Helena, the state capital of Montana, is located on the eastern edge and Missoula is located near the northwestern corner of the quadrangle. Most of the area of the quadrangle is in Granite, Powell, Lewis and Clark, and Jefferson Counties and the remaining area includes parts of Missoula, Ravalli, Deer Lodge, and Silver Bow Counties. The quadrangle includes a number of major and minor mountain ranges separated by intermontane valleys. The continental divide trends nearly north-south through the eastern part of the quadrangle to a point near Butte, then trends generally east-west near the southern boundary of the quadrangle, west of Butte. East of the divide the drainages are tributary to the Missouri River and west of the divide the drainages are tributary to the Clark Fork, which heads in the vicinity of Butte. The geology of the Butte quadrangle is very complex. Sedimentary and igneous rocks range in age from Proterozoic to Tertiary. Most of the pre-Tertiary sedimentary rocks are structurally complex due to widespread faulting and folding. Due to thrust faulting, complete sequences of these sedimentary units are not generally present in the quadrangle and the thicknesses and lithologies are variable from one thrust plate to another. The oldest rocks in the quadrangle are sedimentary rocks of the Belt Supergroup of Middle Proterozoic age. They form very thick sequences, are exposed over a large percentage of the area of the quadrangle, and include formations of the lower, middle, and upper parts of the Belt. Individual formations are as much as 13,000 ft thick (C. A. Wallace, unpub. data) and the maximum thickness of the Belt Supergroup in the quadrangle may be similar to that of the entire sequence near Alberton, Montana, to the northwest of the Butte quadrangle where it exceeds 67,000 ft (Harrison, 1972). In many areas of the quadrangle these Precambrian rocks are overlain by thin to moderately thick sequences of Cambrian to Permian sedimentary rocks. The maximum thickness of the Paleozoic section is about 8,000 ft (C. A. Wallace, unpub. data). A relatively thick sequence of Mesozoic sedimentary rocks, predominantly Cretaceous in age, which is found mostly in the central part of the quadrangle, overlies the Paleozoic rocks. If complete, the Mesozoic sequence would total about 28,000 ft (C. A. Wallace, unpub. data). The Butte quadrangle is located in a structurally complex region. Most of the Butte quadrangle is in the southern part of the Montana Disturbed Belt, a tectonic belt in the Northern Rocky Mountains characterized by northwest-trending faults and intense deformation. An element of the Disturbed Belt, called the Sapphire Thrust System occupies most of the western two-thirds of the quadrangle. Sedimentary rocks of Cretaceous and older ages in the Sapphire Thrust System have been complexly folded and faulted. Plutonic rocks, which intrude the sedimentary units, and volcanic rocks of Cretaceous and Tertiary ages are widespread in the quadrangle. Most of these are post-thrusting but some may be pre- or syn-tectonic and involved in the thrusting and folding. Most of the mineral wealth in the quadrangle, in the form of hydrothermal ore deposits, is genetically related to Cretaceous granitic plutonism. Igneous activity decreased but continued into Tertiary time, at least until the Oligocene. In the Butte quadrangle the Cenozoic Era was important for normal faulting, volcanism, sedimentation, glaciation, and the formation of many important mineral deposits. Many normal faults were especially active during the Miocene and Pliocene and some were active into the Quaternary. Volcanic rocks of Eocene and Oligocene age cover large areas and are genetically related to several important mining districts. During Cenozoic time, thick accumulations of Tertiary basin-fill sediments, Pleistocene glacial till and outwash, and Holocene alluvium and colluvium were deposited. The Cenozoic was important for the formation of placer deposits valuable mainly for gold but some have produced important quantities of sapphires and tungsten. This map is part of a folio of maps of the Butte 1° x 2°quadrangle, Montana, prepared under the Conterminous United States Mineral Assessment Program (CUSMAP). Other maps to be published as part of this folio are a geologic map, geochemical maps, geophysical maps, maps of linear features and limonitic alteration interpreted from satellite and airborne radar data, and mineral resource assessment maps.

Montana↗

USGS2004

Water Quality of the Snake River and Five Eastern Tributaries in the Upper Snake River Basin, Grand Teton National Park, Wyoming, 1998-2002

To address water-resource management objectives of the National Park Service in Grand Teton National Park, the U.S. Geological Survey in cooperation with the National Park Service has conducted water-quality sampling in the upper Snake River Basin. Routine sampling of the Snake River was conducted during water years 1998-2002 to monitor the water quality of the Snake River through time. A synoptic study during 2002 was conducted to supplement the routine Snake River sampling and establish baseline water-quality conditions of five of its eastern tributaries?Pilgrim Creek, Pacific Creek, Buffalo Fork, Spread Creek, and Ditch Creek. Samples from the Snake River and the five tributaries were collected at 12 sites and analyzed for field measurements, major ions and dissolved solids, nutrients, selected trace metals, pesticides, and suspended sediment. In addition, the eastern tributaries were sampled for fecal-indicator bacteria by the National Park Service during the synoptic study. Major-ion chemistry of the Snake River varies between an upstream site above Jackson Lake near the northern boundary of Grand Teton National Park and a downstream site near the southern boundary of the Park, in part owing to the inputs from the eastern tributaries. Water type of the Snake River changes from sodium bicarbonate at the upstream site to calcium bicarbonate at the downstream site. The water type of the five eastern tributaries is calcium bicarbonate. Dissolved solids in samples collected from the Snake River were significantly higher at the upstream site (p-value<0.001), where concentrations in 43 samples ranged from 62 to 240 milligrams per liter, compared to the downstream site where concentrations in 33 samples ranged from 77 to 141 milligrams per liter. Major-ion chemistry of Pilgrim Creek, Pacific Creek, Buffalo Fork, Spread Creek, and Ditch Creek generally did not change substantially between the upstream sites near the National Park Service boundary with the National Forest and the downstream sites near the Snake River; however, variations in the major ions and dissolved solids existed between basins. Variations probably result from differences in geology between the tributary basins. Concentrations of dissolved ammonia, nitrite, and nitrate in all samples collected from the Snake River and the five eastern tributaries were less than water-quality criteria for surface waters in Wyoming. Concentrations of total nitrogen and total phosphorus in samples from the Snake River and the tributaries generally were less than median concentrations determined for undeveloped streams in the United States; however, concentrations in some samples did exceed ambient total-nitrogen and total-phosphorus criteria for forested mountain streams in the Middle Rockies ecoregion recommended by the U.S. Environmental Protection Agency to address cultural eutrophication. Sources for the excess nitrogen and phosphorus probably are natural because these basins have little development and cultivation. Concentrations of trace metals and pesticides were low and less than water-quality criteria for surface waters in Wyoming in samples collected from the Snake River and the five eastern tributaries. Atrazine, dieldrin, EPTC, or tebuthiuron were detected in estimated concentrations of 0.003 microgram per liter or less in 5 of 27 samples collected from the Snake River. An estimated concentration of 0.008 microgram per liter of metolachlor was detected in one sample from the Buffalo Fork. The estimated concentrations were less than the reporting levels for the pesticide analytical method. Suspended-sediment concentrations in 43 samples from the upstream site on the Snake River ranged from 1 to 604 milligrams per liter and were similar to suspended-sediment concentrations in 33 samples from the downstream site, which ranged from 1 to 648 milligrams per liter. Suspended-sediment concentrations in 38 samples collected from the tributary streams ranged from 1 t

Scientific Investigations Report↗

USGS2011

Classifying the water table at regional to continental scales

Water tables at regional to continental scales can be classified into two distinct types: recharge-controlled water tables that are largely disconnected from topography and topography-controlled water tables that are closely tied to topography. We use geomatic synthesis of hydrologic, geologic and topographic data sets to quantify and map water-table type over the contiguous United States using a dimensionless criterion introduced by Haitjema and Mitchell-Bruker (2005), called the water-table ratio, which differentiates water-table type. Our analysis indicates that specific regions of the United States have broadly contiguous and characteristic water-table types. Water-table ratio relates to water-table depth and the potential for regional groundwater flow. In regions with recharge-controlled water tables, for example the Southwest or Rocky Mountains, USA, water-tables depths are generally greater and more variable and regional groundwater flow is generally more important as a percentage of the watershed budget. Water-table depths are generally shallow and less variable, and regional groundwater flow is limited in areas with topography-controlled water tables such as the Northeast USA. The water-table ratio is a simple but powerful criterion for evaluating regional groundwater systems over broad areas.

Geophysical Research Letters↗

USGS2015

California State Waters Map Series: Offshore of Refugio Beach, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Refugio Beach map lies within the western Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 0.5 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The coastal zone of this map area lies at the steep flank of the Santa Ynez Mountains. The crest of the range, which lies about 8 km from the shoreline (north of the map area), has a maximum elevation of about 780 m. This area is largely open space, partly used for livestock grazing, with no significant towns or population centers. Highway 101 crosses the map area, adjacent to and within a few hundred meters of the shoreline. The most significant developments are the recreational state beaches at El Capitan Beach and Refugio Beach. The beaches are subject to erosion each winter during storm-wave attack, and then they undergo gradual recovery or accretion during the more gentle wave climate of the late spring, summer, and fall months. The Offshore of Refugio Beach map area lies in the west-central part of the Santa Barbara littoral cell, which is characterized by west-to-east transport of sediment from Point Arguello on the northwest to Hueneme and Mugu Canyons on the southeast. Longshore drift rates have been reported to range from about 160,000 to 800,000 tons/yr, averaging 400,000 tons/yr. Sediment supply to the western and central part of the littoral cell, including the map area, is mainly from relatively small coastal watersheds. Within the map area, these coastal watersheds include (from east to west) Cañada del Capitan, Tajiquas Creek, Arroyo Hondo, Cañada del Molino, and several unnamed canyons and creeks. The Santa Ynez and Santa Maria Rivers, the mouths of which are 80 to 120 km northwest of the map area, are not considered significant sediment sources because Point Conception and Point Arguello provide obstacles to downcoast sediment transport and also because much of their sediment load is trapped in dams. The Ventura and Santa Clara Rivers, the mouths of which are about 70 km to the southeast of the map area, are not sediment sources for the map area. The offshore part of the map area consists of relatively flat and shallow continental shelf, which dips gently seaward (about 0.8° to 1.0°) so that water depths at the shelf break, roughly coincident with the California’s State Waters limit, are about 80 to 100 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. The shelf is underlain by variable amounts of upper Quaternary marine and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. In the map area, the shelf break is at depths of about 90 m and lies about 5.6 to 6.4 km offshore. Beyond the shelf break, the slope is steep (as much as about 7°) and unstable. Several submarine landslides, including the large (130 km 2 ) Goleta landslide complex, have been documented offshore of Goleta, a few kilometers east of the map area. This compound slump complex may have been initiated more than 200,000 year ago, but it also includes three recent failures that may have been generated 8,000 to 10,000 years ago. A local, 10-m-high tsunami may have been generated from these failure events. Small folds related to local faulting are superimposed on the homocline that makes up the south flank of the Santa Ynez Mountains. One of these superimposed anticlines hosts the Molino gas field, which was discovered in 1962 and subsequently developed through directional drilling from onshore wells. The Oligocene Sespe and Vaqueros Formations are the reservoirs in the Molino gas field, and the map area includes numerous seafloor hydrocarbon seeps. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft, unconsolidated sediment interspersed with isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Refugio Beach map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, primarily are composed of soft sediment interrupted by a few carbonate mounds. This homogeneous seafloor of sediment and low-relief bedrock provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms.

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