Solid masses that make up the earth's crust as well as accumulations of materials. Use for major rock types and unconsolidated deposits. For deposits of economic value, see related terms.
Second report of a joint project with the Tianjin Geological Academy to study sedimentary rock-hosted Au deposits in China. Links to text in PDF format with appendices in *.pdf, *.xls, *.csv, *.jpg, and *.tif formats. Also readme file of CD-ROM version.
Explanation of how geologists date rocks (to determine the ages of the Earth, fossils, mineral deposits, and other geologic events) and processes using radiometric dating techniques based on radioactive isotopes of carbon and potassium/argon.
Maps and text (Word or PDF format) and database (Excel or HTML format) for bedrock, forest floor, and mineral soil sampling in Voyageurs National Park, Minnesota to establish the background and baseline geochemistry and terrestrial mercury sources.
Site describes studies using flow visualization and rock matrix pressure measurements to study flow through fractures in the unsaturated zone, which plays an important role in water infiltration and contaminant transport.
Part A of a complex report on the results of ROCK-EVAL and vitrinite reflectance analysis of a large sample base from more than 70 wells located in three oil-rich California petroleum basins in order to study the formation of oil deposits.
Links to volcanism, volcanic history, volcanic rocks, and general geology by state, by region, national parks and national monuments and a brief introduction to volcanism around the U.S. entitled: Windows into the past.
U.S. Department of the Interior |
U.S. Geological Survey