Anomalous Thermal Indicators from Authigenic Minerals in Upper Paleozoic Strata of the Michigan Basin

Kyle J. Cox
Western Michigan University

Authigenic mineralization and thermally mature organic material requiring anomalously high paleo-temperatures have been found throughout the Michigan basin. Numerous explanations have been proposed to explain these diagenetic features: an elevated paleo-geothermal gradient, 2 km of post-Pennsylvanian overburden, and hydrothermal fluids from the Mid-Continent Rift found under the basin travelling up through faults and fractures. None has been proven conclusively. Additional investigation into the distribution of these anomalies, the temperature at which they formed, and when they formed is required to determine the mechanism of their creation. Information from the Mississippian and Pennsylvania strata of the basin is especially deficient, but previous investigations have identified abnormal diagenetic features within these shallow formations. This project proposes to test the hypothesis that these diagenetic features are related to the Mid-Continent Rift while providing additional data from an under investigated section of the basin. This will be accomplished through: identification of samples from Upper Paleozoic formations with diagenetic indications of elevated paleo-temperatures through X-ray diffraction and petrographic observation, determination of the temperature of formation for these features through fluid inclusion and isotopic analysis, dating the time of formation through K-Ar age dating, and mapping the results for comparison with the location of the Mid-Continent Rift and associated structures to determine a correlation.

AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013