Preliminary bedrock geologic map data for the eastern Bonnifield mining district, Fairbanks and Healy quadrangles, Alaska

Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. Interpretation and synthesis of this data has been presented in professional and trade meetings. This report and associated geologic map data are preliminary, have not undergone rigorous peer review, and will be superseded by a subsequent Report of Investigations map and report that will be issued later in 2016. The objective of the eastern Bonnifield project is to produce a 1:50,000-scale geologic map to foster a better understanding of the area's geology and mineral potential. Although DGGS concentrated on mapping the Paleozoic metamorphic rocks that host the volcanogenic massive sulfide deposits (VMS) and Mesozoic igneous rocks associated with Au-Ag-As-Sb veins, we also studied the Tertiary sedimentary section, which could contain coal resources. The geologic map data are available in digital format as ESRI shapefiles.