Research procedures and instrumental means to measure, collect data and samples, and observe in the natural areas where the materials, phenomena, structures, or species being studied occur.
Data from seismic reflection and refraction, electromagnetic sounding, and resistivity profiling in a study area in Indiana. Exact location is not provided.
Chemical composition of sediments and soils are of interest because of the potential for human and wildlife health impacts from high metal contents due to over 100 years of mining activity.
Major element oxide and trace element geochemical analyses, including those for gold, silver, and base metals, for representative rock units and for grab samples from quartz veins and mineralized zones within the quadrangle
Report describing detailed interpretation of geophysical survey data to draw inferences about subsurface geologic features and likely consequences for the hydrogeologic system.
Explanation of the Earth's gravitational field, emphasizing how USGS scientists measure gravity and portray these measurements on maps. Explains terminology of gravity anomaly maps and their relationship to the rock types and other geologic features.
Explanation of the Earth's magnetic field and how USGS measures it. Defines magnetic anomaly, induced and remanent magnetism in rocks, and describes magnetic anomaly maps.
Study aids understanding of local geologic structure and ground-water flow, includes principal facts for 266 gravity stations and physical properties of representative rock samples.