Tectonics of the Late Tertiary uplift of the Southern and Central Appalachians
Mary S. Biswal
University of Tennessee, Knoxville
The Appalachian mountain range extends about 2,500 km from Canada to Alabama with highest peak at ~2,000 m. It is highly unlikely that the Appalachian mountain range could have sustained these elevations for over 300 m.y. Since the last orogeny, multiple phases of Tertiary uplift (65-2.6 Ma) have been documented, but are related to poorly understood processes. A large amount of data from inside the modern mountain chain and the adjacent Coastal Plains indicate the present high topography is anomalous and clearly not related to Paleozoic crustal processes. The period between the Mesozoic (200 Ma) and late Tertiary during and after the breakup of Pangea is a time of inconsistent tectonic pulses of resurgence and rejuvenation. Reconstruction of the late Tertiary Appalachian tectonics (23-2.6 Ma) is necessary in order to understand the recent rejuvenation and uplift of the Appalachians. We believe the late Tertiary uplift of the Appalachians is a tectonic phenomenon with prominent consequential geomorphology.
The Appalachian Mountains have been a source of sediments carried by the Mississippi River over the past 65 m.y. We will perform LaserChron age dating on zircons from sediment samples collected from the Gulf and Atlantic Coastal Plains. We expect mixed age characteristics for those in the Appalachians, as the tectonic uplift in the late Tertiary would provide this mixed provenance. Cosmogenic dating of late Tertiary terrace deposits and mapping of river terraces will provide additional correlation of late Tertiary tectonic activity.
AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013