NEW LOW-TEMPERATURE THERMOCHRONOLOGY DATES FROM MICHIGAN BASIN CORE SAMPLES REVEAL EARLY REHEATING EVENTS IN BASIN HISTORY

The formation mechanisms of cratonic basins have been a subject of debate for decades in part due to the lack of access to the deeply buried rocks that make up the basins themselves. In the Michigan Basin in Michigan, USA, we have access to extensive drill-cores that can be utilized to study the buried units of the basin to better understand how cratonic basins form and evolve through time. Low-temperature thermochronology allows us to track the timing and rate of crustal heating and cooling associated with burial and exhumation events. We present a new multi-thermochronometer dataset (zircon and apatite (U-Th)/He and apatite fission track) using core samples from the Michigan Basin spanning the Precambrian basement and Paleozoic sandstones to resolve the Phanerozoic thermal history of the Michigan Basin. Zircon (U-Th)/He data from Precambrian and Cambrian sandstones in the Michigan basin show a steeply sloped negative date-eU correlation with dates spanning from 1.5 to 1032 Ma (Precambrian samples) and 39 to 666 Ma (Cambrian samples). The negative date-eU trend for the Precambrian and Cambrian samples possibly indicates that these samples have experienced some cooling and subsequent reheating event after initial deposition and burial. Zircon (U-Th)/He data from the Ordovician has dates spanning 170 Ma to 705 Ma with no clear date-eU trend suggesting any cooling and reheating of Precambrian and Cambrian samples occurred prior to Ordovician deposition.