Abstract & Bio.

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Date: Thursday, October 21, 2021

Topic: Paleozoic Fold-and-Thrust Belts in the Subsurface of Arctic Alaska and Adjacent Offshore

Speaker: Christopher Connors of Washington and Lee University/USGS

Abstract: It is generally accepted that in Arctic Alaska and the adjacent offshore Paleozoic contractional deformation ceased by the end of the Devonian, with a transition to rifting and passive margin development in the Carboniferous.  Interpretations of newly available 3D, and recently reprocessed 2D, time-migrated seismic reflection data show that, while pre-Mississippian contractional deformation was ubiquitous in the Franklinian megasequence, shortening continued in places for much of the late Paleozoic.  Seismic observations in the Ellesmerian sequence reveal the presence of growth strata and distinct, though subtle, unconformities.  Both stratal relationships are tied to biostratigraphic data from many North Slope wells and document the timing of additional contractional episodes in the early to middle Mississippian, and a separate one likely in the late Pennsylvanian to Permian.  Using principles of fault-related folding, trends of Paleozoic fold-and-thrust belts are determined to be generally east-west, with both north and south vergence.  Timing relationships, overlapping locations, and distinctive structural styles indicate that pre-Mississippian contractional fabrics influenced the subsequent reactivation of many structures in the late Paleozoic.  These observations suggest a more complex late Paleozoic tectonic history than was previously recognized for the region, and merit further study to determine their broader implications for the tectonic evolution and petroleum systems of Arctic Alaska and the adjacent offshore.

Speaker Bio: Christopher Connors is the Pritchard Professor of Geology at Washington & Lee University where he has been a professor for the last 23 years.  At W&L Chris teaches several courses including structural geology and tectonics, field geophysics, and petroleum geology and geophysics.  For the past 30 years Chris has conducted geologic research and interpreted seismic from various basins around the world.  He previously worked at Texaco Exploration, and has consulted for several companies, government agencies and ministries.  He currently holds a Faculty Appointment at the U.S. Geological Survey as a Research Geologist working on the petroleum systems, structural framework and tectonics of Arctic Alaska.  His research interests are in structural geology and geophysics, particularly in the interpretation of seismic reflection data in complexly deformed areas.  He earned a BS from Penn State University, an MS from the University of Pittsburgh and an MA and PhD from Princeton University.

Because of Physical Distancing our luncheons will be virtual until further notice.

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TIME: Virtual doors open at 11:30 (Alaska Time), Announcements start at 11:45, Talk starts at 12:00

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