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Research about San Bernardino, California

Source-linked reports with geographic coverage including San Bernardino, California.

12 recordsLinked to original sources
USGS2021

Diatom record of holocene moisture variability in the San Bernardino Mountains, California, USA.

Lower Bear Lake, in the San Bernardino Mountains, contains a Holocene paleohydrology record for southern California. The diatom and sediment geochemistry record indicates that the region experienced a wet Early Holocene followed by a gradual decrease in precipitation, which was punctuated by four strong and five weak pluvial episodes. The Lower Bear Lake record is compared with that of Silver Lake, a Mojave River terminal lake with headwaters in the San Bernardino Mountains, which exhibited several pluvial events at roughly the same time. The comparison is extended to records in relative proximity to Bear Lake (Dry Lake, Lake Elsinore, and San Joaquin marsh) and to two lakes with headwaters in the Sierra Nevada (Tulare Lake and Owens Lake). All exhibit a wet Early and early Middle Holocene wet interval and gradual drying through the remainder of the Holocene but differ in the expression of the pluvial episodes observed at Lower Bear Lake. The pluvial episodes are likely the result of changes in the storm track that affects the frequency and magnitude of winter storms in the area. These episodes are controlled by complex oceanic and atmospheric interactions and may be the result of the synchronous interaction of several teleconnections.

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USGS2013

Geochronologic and geochemical data from Mesozoic rocks in the Black Mountain area northeast of Victorville, San Bernardino County, California

We present geochronologic and geochemical data for Mesozoic rocks in the Black Mountain area northeast of Victorville, California, to supplement previous geologic mapping. These data, together with previously published results, limit the depositional age of the sedimentary Fairview Valley Formation to Early Jurassic, refine the ages and chemical compositions of selected units in the overlying Jurassic Sidewinder Volcanics and of related intrusive units, and limit the age of some post-Sidewinder faulting in the Black Mountain area to a brief interval in the Late Jurassic. The new information contributes to a more complete understanding of the Mesozoic magmatic and tectonic evolution of the western Mojave Desert and surrounding regions.

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USGS2009

Geospatial Data Used in Water-Level and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins for 2008

During 2008, the U.S. Geological Survey and other agencies made approximately 2,500 water-level measurements in the Mojave River and Morongo groundwater basins. These data document recent conditions and, when compared with previous data, changes in groundwater levels. A water-level contour map was drawn using data from about 700 wells, providing coverage for most of the basins. Twenty-four hydrographs show long-term (up to 70 years) water-level conditions throughout the basins, and 9 short-term (1997 to 2008) hydrographs show the effects of recharge and discharge along the Mojave River. In addition, a water-level-change map was compiled to compare 2006 and 2008 water levels throughout the basins. (575 wells)

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USGS2004

Regional water table (2004) and water-level changes in the Mojave River and Morongo ground-water basins, Southwestern Mojave Desert, California

The Mojave River and Morongo ground-water basins are in the southwestern part of the Mojave Desert in southern California. Ground water from these basins supplies a major part of the water requirements for the region. The continuous population growth in this area has resulted in ever-increasing demands on local ground-water resources. The collection and interpretation of ground-water data helps local water districts, military bases, and private citizens gain a better understanding of the ground-water flow systems, and consequently, water availability. During March and April 2004, the U.S. Geological Survey and other agencies made almost 900 water-level measurements in about 740 wells in the Mojave River and Morongo ground-water basins. These data document recent conditions and, when compared with historical data, changes in ground-water levels. A water-level contour map was drawn using data from 500 wells, providing coverage for most of the basins. In addition, 26 long-term (as much as 74 years) hydrographs were constructed which show water-level conditions throughout the basins, 9 short-term (1992 to 2004) hydrographs were constructed which show the effects of recharge and discharge along the Mojave River, and a water-level-change map was compiled to compare 2002 and 2004 water levels throughout the basins. The water-level change data show that in the Mojave River ground-water basin, more than one half (102) of the wells had water-level declines of 0.5 ft or more and almost one fifth (32) of the wells had declines greater than 5 ft. between 2002 and 2004. The water-level change data also show that about one tenth (17) of the wells compared in the Mojave River ground-water basin had water level increases of 0.5 ft or more. Most of the water-level increases were the result of stormflow in the Mojave River during March 2004, which resulted in recharge to wells in the floodplain aquifer mainly along the river in the Alto subarea and the Transition zone, and along the river east of Barstow. In the Morongo ground-water basin, nearly one half (55) of the wells had water-level declines of 0.5 ft or more, and about one tenth (13) of the wells had declines greater than 5 ft. The Warren subbasin, where artificial-recharge operations in Yucca Valley (pl. 1) have caused water levels to rise, had water-level increases of as much as about 97 ft since 2002.

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USGS2003

1998 Water-Table Contours of the Mojave River and the Morongo Ground-Water Basins, San Bernardino County, California

This data set consists of digital water-table contours for the Mojave River and the Morongo Ground-Water Basins. The U.S. Geological Survey constructed a water-table map of the Mojave River and the Morongo Ground-Water Basins for ground-water levels measured during the spring of 1998. Water-level data were collected from 418 wells to construct the contours. The water-table contours were digitized from the paper map which was published at a scale of 1:175,512. The contour interval rangs from 3,400 to 1,500 feet above sea level.

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USGS2003

2000 Water-Table Contours of the Mojave River and the Morongo Ground-Water Basins, San Bernardino County, California

This data set consists of digital water-table contours for the Mojave River and the Morongo Ground-Water Basins. The U.S. Geological Survey constructed a water-table map of the Mojave River and the Morongo Ground-Water Basins for ground-water levels measured during the spring of 2000. Water-level data were collected from 498 wells to construct the contours. The water-table contours were digitized from the paper map which was published at a scale of 1:175,512. The contour interval ranges from 3,400 to 1,500 feet above sea level.

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USGS2000

Principal facts for gravity stations in the vicinity of San Bernardino, Southern California

New gravity measurements in the vicinity of San Bernardino, California were collected to help define the characteristics of the Rialto-Colton fault. The data were processed using standard reduction formulas and parameters. Rock properties such as lithology, magnetic susceptibility and density also were measured at several locations. Rock property measurements will be helpful for future modeling and density inversion calculations from the gravity data. On both the Bouguer and isostatic gravity maps, a prominent, 13-km long (8 mi), approximately 1-km (0.62 mi) wide gradient with an amplitude of 7 mGal, down to the northeast, is interpreted as the gravity expression of the Rialto-Colton fault. The gravity gradient strikes in a northwest direction and runs from the San Jacinto fault zone at its south end to San Sevine Canyon at the foot of the San Gabriel mountains at its north end. The Rialto-Colton fault has experienced both right-lateral strike-slip and normal fault motion that has offset basement rocks; therefore it is interpreted as a major, through-going fault.

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USGS1986

Mineral resources of the Castle Peaks Wilderness Study Area, San Bernardino County, California

The Castle Peaks Wilderness Study Area (CDCA266) comprises approximately 45,000 acres in the northern New York Mountains, San Bernardino County, California. At the request of the Bureau of Land Management, 39,303 acres of the wilderness study area were studied. The area was investigated during 1982-1985 using combined geologic, geochemical, and geophysical methods. are considered preliminarily suitable for wilderness deignation. There are no mineral reserves or identified resources in the study area. Fluorspar, occurring in sparse veins, has moderate resource potential, as do silver and lead in fault zones, and gold and silver in sparse, high-grade veins and fault breccia. Each area of moderate resource potential encompasses less than one square mile. These same commodities have low resource potential in similar occurrences throughout much of the study area. In addition, there is low resource potential for gold in placer deposits, uranium in altered breccia and gouge, and rare-earth elements in pegmatite dikes. There is no resource potential for oil and gas resources over most of the study area, but the potential is unknown along its western margin. In this report, the area studied is referred to"the wilderness study area", or simply "the study area."

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