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

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At least 163 records · Page 9Linked to original sources
USGS2010

Monitoring and assessment of ocean acidification in the Arctic Ocean-A scoping paper

Carbon dioxide (CO2) in the atmosphere is absorbed at the ocean surface by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution. Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats. The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

Open-File Report↗
USGS1975

Uranium in West Texas -- paper delivered June 3, 1975, AAPG-SEPM Rocky Mountain Section Meeting, Albuquerque, New Mexico

In west Texas, the part north of the Pecos River, anomalous uranium concentrations occur in the Tecovas and Trujillo Formations of the Dockum Group of Late Triassic age, the Edwards Limestone of Early Cretaceous age, the caliche caprock of the Ogallala Formation of Pliocene age, and the Pleistocene Blanco and Tule Formations, Rita Blanca lakebed deposit, and Bandelier and Pearlette ashes. The occurrences in Pleistocene rocks are a mere curiosity at this time, except the Rita Blanca lakebed deposit is large and of higher grade than the rest. Several occurrences of low-grade rock in the caliche caprock of the Ogallala Formation southeast of Lubbock are of interest because of the recent discoveries of large deposits in calcrete (caliche) in Western Australia. The single occurrence of ore-grade material in Cretaceous limestone is probably insignificant. Most of the ore-grade material is found in the Dockum Group, chiefly in the Trujillo Formation and mainly near Post. I plan to briefly describe the geographic and geologic setting of each group of deposits and to assess each group's resource potential.

Texas↗
USGS1982

New papers related to remote sensing of the earth

Worldwide experience of many individuals and organizations with remote sensing data acquired from space, primarily Landsat-1, -2, and -3, has demonstrated its utility for land use classification, agricultural assessment, energy and resource exploration, and many other applications. There has been some reluctance to adopt these systems in operational programmes because of a lack of assured continuity of data collection, continuing changes in the systems, and some dissatisfaction with the types of data made available to users. Nevertheless, there is sufficient conviction of the value of satellite remote sensing so that new systems will be developed by several countries in the decade of the 1980's. The status changes continuously as studies are completed, and budgets are adjusted. This review presents the situation at the beginning of 1982.

Open-File Report↗