Seismological Research Letters; November/December 2004; v. 75; no. 6;
p. 784-793; DOI: 10.1785/gssrl.75.6.784
© 2004 Seismological Society of America
Faulting along the Southeastern Margin of the Reelfoot Rift in Northwestern Tennessee Revealed in Deep Seismic-reflection Profiles
Approximately 320 km of deep seismic-reflection profiles in northwestern
Tennessee reveal the structure of a major portion of the southeastern margin
of the Reelfoot Rift. This rift margin consists of at least two major
down-to-the-west late Precambrian to Cambrian normal faults. Maximum fault
displacement at one location is 3 km. These two faults strike N50°E, in
their northern portions; over their southern extent they trend N30°E
however.
Numerous faults in these reflection lines displace Paleozoic, Cretaceous,
and Tertiary reflectors. The dominantly reverse faulting, folding, and
positive flower structures in the shallower section indicate Eocene or younger
transpression. We believe the late Tertiary faulting is due to reactivation of
the basement faults, because on some of the reflection lines basement normal
faults can be traced into Tertiary reverse faults, the Tertiary faults
parallel the basement faults, and the Tertiary faults overlie or are adjacent
to the basement faults. Numerous faults displace the highest (youngest)
reflectors and therefore we do not know how recently faulting has occurred.
Previous studies have identified Quaternary faulting within the southeastern
Reelfoot Rift margin of western Tennessee, however. Thus, we believe all of
the late Tertiary faults identified in this research should be evaluated for
possible Quaternary movement.
Copyright © 2009 by Seismological Society of America
