Anomalous Thermal Indicators from Authigenic Minerals in Upper Paleozoic Strata of the Michigan Basin
Geosciences, Western Michigan University, Kalamazoo, MI, USA
Burial diagenetic mineralization and thermally-mature organic material requiring anomalously high paleo-temperatures are found throughout the Michigan basin. Several explanations have been proposed to explain these features: an elevated paleo-geothermal gradient, deposition and subsequent uplift and erosion of 2 km of post-Pennsylvanian overburden, and the upward migration of hydrothermal fluids through faults related to the Mid-Continent Rift that underlies the basin. Additional investigation of the spatial and stratigraphic distribution of anomalous diagenetic minerals, and the temperature and timing of formation of these minerals is needed to conclusively determine the geological mechanism(s) involved in the thermal evolution of the basin. Previous investigations have identified anomalous diagenetic features in Middle Devonian and younger strata, but a comprehensive, quantitative investigation of these features is lacking. This project proposes to test the hypothesis that burial diagenetic features in Upper Paleozoic strata of the Michigan basin are related to hydrothermal fluids that migrated from faults related to the basement structures including and most importantly the Mid-Continent Rift. This will be accomplished through identification and analysis of appropriate samples from Upper Paleozoic formations. The analytical techniques proposed for this work include: 1) X-ray diffraction and petrographic observation, 2) determination of the temperature of formation for burial diagenetic mineral phases through fluid inclusion and oxygen isotope analysis, 3) dating of potassium-bearing, authigenic minerals using K-Ar methods, and 4) mapping the results for comparison with the location of the rift and other basement structures to evaluate possible genetic relationships.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects