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Implications for the Tectonic Evolution of the Sea Okhotsk Margin of Eastern Russia |
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Jaime Toro, Assistant Professor of Geology, West Virginia University Elizabeth Miller, Professor of Geology, Stanford University Trevor Dumitru, Consulting Associate Professor of Geological and Environmental Sciences, Stanford University |
Andrei V. Prokopiev, Head of Laboratory of Tectonics, Seismology and Geodynamics Valodia Tarabukin, Conodont Paleontologist, Leonid M. Parfenov, Head of the institute |
The Verkhoyansk fold-and-thrust belt forms part of one of Earth's
great orogenic systems. It separates the North Asian Craton to
the west from the immense expanse of accreted terranes which form
most of the Russian Far East (Parfenov, 1995). In a sense, this
vast orogenic belt is the mirror image of the North American Cordillera,
yet because of its remote and inaccessible location its tectonic
history is poorly understood, particularly to the Western geological
community.
We propose to carry out two modern structural and thermochronologic
transects in the Verkhoyansk fold-and-thrust-belt designed to
address some of the outstanding questions about the tectonic evolution
of the belt as well as some more regional problems. One of these
transects would be located in the Southern Verkhoyansk and one
in the Northern Verkhoyansk thus allowing us to evaluate the differences
in structural evolution from different portions of the orogen.
The transects would span from the foreland, through the supracrustal
thrust belt and into the metamorphic hinterland. Along each transect
we would carry out structural analysis and collect samples of
the main stratigraphic units for petroleum systems evaluation,
for detailed petrographic work, and for thermochronologic studies
which will help elucidate the kinematics, the timing of deformation,
and the thermal history of the belt. Specifically we will carry
out apatite fission-track, vitrinite reflectance, 40Ar/39Ar ,
and U-Pb (SHRIMP) geochronology of appropriate rocks. Because
these cutting-edge laboratory techniques have not been previously
applied to area they are bound to greatly enhance our geological
understanding of the tectonic history of the Verkhoyansk fold-and-thrust-belt
and more generally of the Russian Far East region.
In addition to the Stanford Structural Geology and Tectonics
group, we have assembled a team of scientists which include two
of the foremost structural geologists of Yakutia. They are experts
on the stratigraphy and structure of the Verkhoyansk fold-and-thrust-belt
and have, for a long time now, utilized modern methods of cross-section
construction and balancing, and who have already made fundamental
contributions to our understanding of the tectonics of North Asia.
Together we will be able to accomplish more than is usual for
the two year span outlined for this proposal.