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At least 1,585 records · Page 88Linked to original sources
USGS2002

Techniques for assessing sand and gravel resources in glaciofluvial deposits — An example using the surficial geologic map of the Loudon quadrangle, Merrimack and Belknap Counties, New Hampshire

A method for estimating the sand and gravel resources in glaciofluvial systems has been developed based on surficial mapping techniques that use the morphosequence concept and geographic information systems (GIS). Two different strategies are used to estimate gravel resources. One strategy estimates the sand and gravel resources contained in esker deposits; the other, which is more dependent on GIS, estimates resources in non-esker deposits. An attempt has been made to determine which deposits are sterilized; that is, those beneath the water table, adjacent to streams or roads, or encroached on by urbanization. Preliminary estimates using these methods indicate that about 158,000,000 m3 (206,000,000 yd3) of sand and gravel are present in the Soucook River valley part of the Loudon, N.H., 7.5-minute quadrangle. About 64,500,000 m3 (84,400,000 yd3) of these materials are in deposits above the water table. About 26 percent of the sand and gravel resources above the water table are unlikely to be mined because they have been sterilized. Of the remaining resources, 479,000 m3 (627,000 yd3) of gravel and 1,120,000 m3 (1,460,000 yd3) of sand are in esker deposits, and 9,400,000 m3 (12,300,000 yd3) of gravel and 38,300,000 m3 (50,100,000 yd3) of sand are in stratified non-esker deposits. With the addition of new well data, newer and more accurate estimates are possible.

New Hampshire↗
USGS2008

Geologic Map of the Cedargrove Quadrangle, Dent and Shannon Counties, Missouri

The Cedargrove 7.5-minute quadrangle is located in south-central Missouri within the Salem Plateau region of the Ozark Plateaus physiographic province. Most of the land in the quadrangle is privately owned and used primarily for grazing cattle and horses and growing timber. The map area has topographic relief of about 565 feet (ft), with elevations ranging from about 760 ft at Akers Ferry on the central-southern edge of the map to about 1,325 ft near the town of Jadwin in the north-central part of the map area. The most prominent physiographic features in the quadrangle are the valleys of the Current River and Big Creek in the southwestern part of the map area, and the valley of Gladden Creek, which transects the eastern part of the quadrangle from north to south.

Scientific Investigations Map↗
USGS2008

Geologic Map of the Abiquiu Quadrangle, Rio Arriba County, New Mexico

The Abiquiu 1:24,000-scale quadrangle is located along the Colorado Plateau-Rio Grande rift margin in north-central New Mexico. The map area lies within the Abiquiu embayment, an early (pre-Miocene) extensional basin of the Rio Grande rift. Rocks exposed include continental Paleozoic and Mesozoic rocks of the Colorado Plateau and Cenozoic basin-fill deposits and volcanic rocks of the Rio Grande rift. Paleozoic units include the Late Pennsylvanian to Early Permian Cutler Group, undivided. Mesozoic units are Upper Triassic Chinle Group, undivided, middle Jurassic Entrada Sandstone, and Todilto Limestone Member of the Wanakah Formation. Mesozoic rocks are folded in some areas and overlain disconformably by Cenozoic rocks. Cenozoic sedimentary rocks are composed of the Eocene El Rito Formation, Oligocene Ritito Conglomerate, Oligocene-Miocene Abiquiu Formation, and Miocene Chama-El Rito and Ojo Caliente Sandstone Members of the Tesuque Formation of the Santa Fe Group. Volcanic rocks include the Lobato Basalt, the El Alto Basalt, and dacite of the Tschicoma Formation. Quaternary deposits consist of inset ancestral axial and tributary Rio Chama deposits and Holocene floodplain alluvium, fan and pediment alluvium, and landslide colluvium.

Scientific Investigations Map↗
USGS2008

Geologic Map of the Elkhorn Quadrangle, Park County, Colorado

The Elkhorn thrust is defined by the juxtaposition of Early and Middle Proterozoic metamorphic and igneous rocks against Mesozoic and Tertiary rocks. Within the mapped area, an imbricate frontal thrust system juxtaposes Upper Cretaceous rocks against Paleocene rocks of the South Park Formation. In the southeastern section of the quadrangle, Middle Proterozoic igneous rocks are thrust over the South Park Formation. Syntectonic conglomerates (Txc) are preserved both on the hanging wall and footwall of the Elkhorn thrust. North of the map area we have identified normal faulting of probable Quaternary age.

Scientific Investigations Map↗
USGS2018

Geologic map of the Hayfield quadrangle, Frederick County, Virginia

The Hayfield 7.5-minute quadrangle is located within the Valley and Ridge physiographic province of northern Virginia. The quadrangle includes the topographical lowland area of the northern Great Valley to the southeast, the narrow ridge of Little North Mountain along the western edge of the Great Valley, and the broad region of elongated valleys and ridges west of Little North Mountain. The most prominent physiographic feature within the quadrangle is Great North Mountain, which extends across the northwestern portion of the quadrangle. All exposed bedrock units are Paleozoic sedimentary rocks ranging from Middle Cambrian to Late Devonian, approximately 513 to 359 Ma. The clastic and carbonate sedimentary strata in the quadrangle reflect nearshore and offshore marine and deltaic depositional environments. The deposits indicate minor sea level transgression and regression cycles along a passive continental margin during the Late Cambrian to Middle Ordovician, and major sea level changes resulting from tectonic uplift during the Late Ordovician Taconian orogeny and the Middle to Late Devonian Acadian orogeny. Compressive forces caused by the continental collision during the Paleozoic Alleghanian orogeny resulted in folding and faulting of the sedimentary rock strata, with northwestward tectonic transport. The North Mountain fault zone, spanning across the southeastern part of the quadrangle, forms the western border of the Great Valley in northern Virginia and is a series of northeast-trending thrust faults with multiple splays that separate the Silurian and Devonian shales, siltstones, and sandstones from the Cambrian and Ordovician carbonate rocks and shales. Topographic ridges in the quadrangle are primarily held up by sandstones and orthoquartzites that are relatively resistant to erosion. Surficial materials include unconsolidated alluvium, colluvium, debris flow, and terrace deposits that are assumed to be of Quaternary age. Alluvium was mapped along the larger streams; locally, some low alluvial terraces exist but have not been broken out within this unit. Debris flow deposits were mapped where recognized in the lidar-derived topographic imagery on the flanks of Great North Mountain. Colluvium (not mapped separately) covers most of the steeper slopes and fills the bottoms of many of the mountain hollows, and is composed mainly of sandstone boulders and cobbles, and fragments of chert.

Virginia↗
USGS2018

Geologic map of the Timberville quadrangle, Virginia

This map of the Timberville 7.5-minute quadrangle in Rockingham and Shenandoah counties, Virginia shows the distribution of Paleozoic-age sedimentary rocks in map and cross-section. Surficial deposits including alluvium and colluvium are also shown. The characteristics of each map unit are described and a brief report discusses the stratigraphy, structure and mineral resources of the area.

Virginia↗
USGS2019

Geologic map of the Hartsel Quadrangle, Park County, Colorado

The Hartsel quadrangle sits nearly in the center of the complex South Park Laramide structural basin. Generally, the basin can be described as an asymmetrical down-faulted feature, dipping to the east. It is bounded by two northwest-trending uplifts: the Sawatch uplift to the west and the Front Range uplift to the east. The west-verging Elkhorn thrust, which places Proterozoic intrusive and metamorphic rocks within the Front Range uplift over Phanerozoic sediments in the basin, passes just east of the quadrangle. Seismic data and deep oil and gas well logs indicate that a series of imbricate thrust faults extend west, and in front of, the Elk horn thrust fault. The Hartsel uplift is a westward-jutting structural salient of the Front Range uplift that brings Proterozoic rocks farther into the basin south of the town of Hartsel. The quadrangle also spans the late Paleozoic boundary between the central Colorado trough (DeVoto, 1972) to the west and Frontrangia (Mallory, 1958) to the east. The Neogene Rio Grande rift system lies to the west of South Park Basin in the upper Arkansas River valley. Examples of Neogene extension can be found throughout South Park, as described by Stark and others (1949), De Voto (1971), and Ruleman and others (2011). In addition, there is evidence of ongoing local deformation related to dissolution and possible collapse of Paleozoic evaporite deposits across much of the west side of the basin (Kirkham and others, 2012).

Colorado↗
USGS2013

Hyperspectral surface materials map of quadrangle 3468, Chak-e Wardak-Siyahgird (509) and Kabul (510) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

Open-File Report↗