Joseph Colgan
I study magmatism and deformation of the earth’s crust, and how these processes influence the formation and distribution of natural resources and geologic hazards. This work involves geologic mapping at different scales, interpretation of subsurface and geophysical data, and laboratory analyses to determine the age and composition of rocks and minerals.
Science and Products
National Geologic Mapping
To “bring together detailed national, and continental resolution 2D and 3D data produced throughout the USGS and state partners,” NGS developed a model in which geologic map databases produced by the USGS and State Geological Surveys can be assembled into compilation maps by an automated process, enabling rapid delivery of a new national map that can grow thereafter with contributions from the...
National Geologic Synthesis
Surface (2D) and subsurface (3D) geologic data are critical for resource management, infrastructure design, hazards characterization, and basic earth science research. To meet these needs in a digital landscape, geologic maps must transition from static publications to machine-readable and discoverable digital databases that enable spatial analyses and queries (Shelton and others, 2022). In 2019...
Serving the U.S. Geological Survey’s geochronological data
Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years...
Science and Products
National Geologic Mapping
To “bring together detailed national, and continental resolution 2D and 3D data produced throughout the USGS and state partners,” NGS developed a model in which geologic map databases produced by the USGS and State Geological Surveys can be assembled into compilation maps by an automated process, enabling rapid delivery of a new national map that can grow thereafter with contributions from the...
National Geologic Synthesis
Surface (2D) and subsurface (3D) geologic data are critical for resource management, infrastructure design, hazards characterization, and basic earth science research. To meet these needs in a digital landscape, geologic maps must transition from static publications to machine-readable and discoverable digital databases that enable spatial analyses and queries (Shelton and others, 2022). In 2019...
Serving the U.S. Geological Survey’s geochronological data
Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years...