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.
Detailed background information with descriptions of sites and photos explaining the geology of this organic-rich shale unit that has recently become a significant source of natural gas resources.
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.
Characteristics of recent tsunami deposits, with the knowledge we have about the events that caused them, give us ways to recognize ancient deposits of this type and infer characteristics of those ancient tsunamis as well.
Report presents an abridged guide for laboratory technicians and students using X-ray powder diffraction methodology to study crystalline structure and to determine the mineralogy of finer grained sediments, especially clays.
Uses and availability of limestone and related commodities such as lime and portland cement. Hazards of limestone terranes due to erosion and sinkhole formation.
Discusses how fossils can be grouped and studied by size, habitat type, and phylogenetic groups. Shows how fossil classification groups are used to solve geologic problems at the USGS.
Regional studies mapping the seafloor sedimentary character and assessing marine sand and gravel resources around the United States, to inform beach nourishment and coastal restoration, benthic habitat and sediment transport studies