The Tectonics and Sedimentation Research Group has been studying the geological evolution of the northeastern Brooks Range since 1986. These studies address various aspects of the geology of the northeastern Brooks Range, a rugged and inaccessible part of northern Alaska. The goal of these studies is to develop a comprehensive understanding of the character and evolution of the region while establishing the geological framework of the coastal plain of the Arctic National Wildlife Refuge. Because of the high potential for petroleum discoveries on the coastal plain, this work has been funded primarily by the petroleum industry and the Department of Energy.
The group's efforts have focused on the sedimentary rocks of the region, their environments of deposition, and their subsequent deformation. Most of the rocks were deposited on the rifted edge of an ancient continent, similar to the present continental margins bounding the Atlantic Ocean. Unlike the present geography, the continent lay to the north and the ocean lay to the south at the time of deposition.
Wes Wallace, Cathy Hanks, and their graduate students have studied how rocks were folded and faulted to form the northeastern Brooks Range, which provides clues to the origin of mountain belts in general. As in the Rocky Mountains, this deformation took place far within a continent, but was related to relative plate motions at a distant convergent continental margin.
Keith Crowder and his graduate students have studied a variety of ancient terrigenous clastic rocks to interpret their environments of deposition and erosional gaps in the sedimentary record. These deposits were derived from erosion of a continent to the north and were deposited in ancient rivers, deltas, and continental shelves.
Keith Watts and his graduate students have studied carbonate rocks to reconstruct the paleogeography of the ancient continental margin and to understand depositional cycles that reflect changes in relative sea level. These rocks are mainly limestones and dolostones derived from marine organisms, comparable to those forming today in the Bahamas and Persian Gulf.
Paul Layer has begun 40Ar/39Ar dating of granitic rocks to constrain the age of tectonically significant thermal events. These dates will be combined with the results of structural studies and fission-track dating by Paul O'Sullivan (LaTrobe University, Australia) to determine when and where deformation and uplift occurred in the northeastern Brooks Range, and how those events affected the coastal plain to the north.
ARCO Alaska, BP Exploration (Alaska), Chevron USA, Exxon Company USA,
Japan National Oil Corp., Mobil Exploration and Producing US, Phillips
Petroleum, Unocal, and U.S. Department of Energy funds.
Scientific Personnel:
W.K. Wallace,
C.L. Hanks,
R.K. Crowder,
K.F. Watts,
P. Layer,
D. Stone,
A. Anderson, W. Camber, J. Clough, M. Eckstein, N. Harun, T. Homza, A.
Krumhardt, D. LePain, S. Morgan, M. Myers, E. Pavia, P. Peapples, and C.
Petersen (joint with
Geophysical Institute
and UAF Department of Geology and Geophysics)
