T10 Sedimentary Provenance and Evolution of the Continental Crust: Precambrian to Present

Sunday, 9 October 2011
8:00 AM - 12:00 PM
Room 200DE

PRELIMINARY PROVENANCE TRENDS FROM UPPER PALEOZOIC STRATA OF THE MICHIGAN BASIN: IMPLICATIONS FOR CONTINENT-SCALE SEDIMENT DISPERSAL ACROSS EASTERN NORTH AMERICA

Paper number: T10-6
Program: Technical Sessions
Time: 9:05 AM – 9:20 AM

Authors

Abstract

The Michigan basin is one of several intracratonic basins located between the distal margin of the Appalachian foreland (adjacent to the Cincinnati-Findlay-Algonquin arch system) and the southern boundary of the Canadian Shield. The uppermost strata (Mississippian–Pennsylvanian) of the Michigan basin are primarily siliciclastic and represent the last preserved relict of fluvial-deltaic sedimentation coeval with early Alleghenian orogenesis. Previous studies suggest that these strata were derived from source areas associated with the Appalachian orogen, however the timing and spatial distribution of these depositional systems throughout eastern Laurentia remains unknown. Here, we present a summary of new provenance data, including detrital framework modal composition trends and the first set of U-Pb detrital zircon ages (n=431) from the Michigan basin, which indicate an upsection transition in detrital contributions from Mississippian to Pennsylvanian time.

U-Pb detrital zircon age spectra from Mississippian strata of the Marshall Sandstone reveal occurrences of Paleozoic, Neoproterozoic, and Mesoproterozoic ages with primary peaks between 450–465, 1010–1015, 1150–1225, and 1460–1490 Ma. Paleoproterozoic and older detrital zircons are rare and account for <4% of grains. Pennsylvanian strata of the Parma Sandstone, Saginaw Formation, and Eaton Sandstone exhibit similar peak occurrences between 430–475, 1030–1050, 1125–1150, and 1360–1490 Ma and also contain >25% Paleoproterozoic and Archean age zircons with peaks at 1650, 1785, 1805 1840, and 2810 Ma. These findings correspond with trends in modal composition that vary upsection from Mississippian to Pennsylvanian time.

Occurrences of Mesoproterozoic and younger zircons in these strata are interpreted to reflect detrital contributions from eastern Laurentia (e.g. Appalachian, Grenville, and Granite/Rhyolite provinces). Greater relative abundances of Paleoproterozoic and older zircons in Pennsylvanian strata may reflect an introduction of detritus from Midcontinent and cratonic sources (e.g. Central Plains/Labrador, Trans Hudson/Penokean, and Superior provinces) and are coeval with structural reactivation of the Cincinnati-Findlay-Algonquin arch system during initial Alleghenian orogenesis.