About Lloyd C. Furer Cross Sections Collection

Lloyd Furer, former geologist at the Indiana Geological Survey and instructor at Indiana’s famous field camp in Montana, spent decades interpreting and correlating geophysical logs from oil and gas wells across the northern Great Plains and Rocky Mountains. His work resulted in paper records of thousands of log interpretations and hundreds of cross sections that he recently donated to several “state surveys,” including the Montana Bureau of Mines and Geology. This collection of cross sections comprises a portion of Lloyd’s work in Montana.

Each cross section is an interpretation of the geologic layers that occur in the subsurface between oil and gas drillholes. For each well on the cross section, geologic formations were inferred from geophysical and lithological logs. Geologic formations were then correlated and hand-drawn between wells to present an interpretation of the inter-well geology beneath the surface. Some of the cross sections are regional, covering large portions of Montana; others are local, focused only on specific areas or oil/gas fields.

These cross sections are an excellent resource for geologists actively working in Montana and for those doing geologic research in Montana–particularly those involved with subsurface geology, resource exploration, hydrogeology, water/CO2 disposal, seismic hazards, and academia. Cross sections that depict regional changes in stratigraphic sequences and/or layer thicknesses also provide insight into the structural controls and depositional environments active during Montana’s geologic past.

This collection of geologic cross sections represents a wealth of knowledge made available to the public through Lloyd Furer’s generous donation and the efforts of the MBMG data preservation group.