Stephen S. Harlan

Associate Professor of Geology

Department of Environmental Science and Policy

George Mason University

Fairfax, VA 22030-4444

Telephone: (703) 993-3892

Fax: (703) 993-1066

E-mail

Ph.D. University of New Mexico

M.Sc. Montana State University

B.Sc. The Evergreen State College

Professional Background:

Dr. Harlan received a B.S in Environmental Sciences from the Evergreen State College in 1980, a M.Sc. degree in Earth Sciences from Montana State University in 1986, and a Ph.D. in Geology from the University of New Mexico in 1992. From 1990 to 1999 he was employed by the U.S. Geological Survey in a variety of capacities, including positions with the Branch of Isotope Geology and the Global Change and Climate Team. In January, 2000, Dr. Harlan joined the Geography and Earth Sciences Department at GMU. He is currently an Associate Professor in the GMU Environmental Sciences and Policy Department. In addition to his regular faculty position at GMU, he served from 2003 to 2006 as a Program Director for the Tectonics Program of the Earth Sciences Division, National Science Foundation. As of 2008, he has returned to NSF and is currently serving as a Program Director in the Deep Earth Processes Section of the Earth Sciences Division, Geosciences Directorate.

Research Interests:

Structural geology, strain analysis, and the evolution of thin- and thick-skinned thrust belts; particular emphasis on the interaction between both structural styles in southwestern Montana and northwestern Wyoming.

Structural and tectonic evolution of western North America—Proterozoic to Recent

Origin and distribution of large Tertiary to Recent calderas and associated volcanic systems in the in the western U.S.

Paleomagnetism/Rock Magnetism:

o Precambrian paleomagnetism of North America with emphasis on the Middle and Late Proterozoic and reconstruction of Proterozoic continental configurations; application of ⁴⁰Ar/³⁹Ar geochronology to dating the age of remanence acquisition in igneous and metamorphic rocks.

o Timing of thin-skinned thrust belt and basement-involved deformation in the central and southern Rocky Mountains using paleomagnetism and high-precision ⁴⁰Ar/³⁹Ar geochronology.

o Application of paleomagnetism to identification and quantification of vertical- and horizontal-axis (tilt) rotations in contractional, extensional and strike-slip regimes.

o Use of anisotropy of magnetic susceptibility (AMS) and related techniques in the analysis of structural fabrics in igneous and metamorphic rocks, and as primary flow indicators in ash-flow tuffs and dikes.

o Use of paleomagnetism to identify and/or constrain the temperature of emplacement of pyroclastic flows, breccias, and related deposits.

o Rock magnetic investigations of soil/loess sequences as a proxy for records of Quaternary climate change.

Geochronology:

o Use of ⁴⁰Ar/³⁹Ar and U-Pb geochronology to study the thermal evolution of igneous and metamorphic terranes.

o Use of ⁴⁰Ar/³⁹Ar geochronology of Late Cretaceous/Tertiary volcanism in the western U.S.

o Use of ⁴⁰Ar/³⁹Ar, U-Pb, and Sm-Nd isotopic systems to date the age of emplacement of Precambrian mafic dikes and sills.

o Application of the close relationship between laboratory unblocking temperatures of magnetic phases and the closure temperatures of common potassium-bearing minerals used in ⁴⁰Ar/³⁹Ar dating in order to date the age of remanence acquisition in paleomagnetic studies.

o Dating of precious metal deposits and thermochronologic studies of basement rocks in central Alaska by the ⁴⁰Ar/³⁹Ar, U-Pb, and fission track methods.

Applications of Geographic Information Systems (GIS), Database Systems, and remotely sensed data to the solution of geologic, structural, and tectonic problems, including the production of digital geologic maps.

Publications:

Selected Publications and Reports

Other Items of Interest

Mafic Dikes of the Beartooth Mountains

Gunbarrel Magmatic Event (note: the Gunbarrel magmatic event was featured as the February 2004 LIP of the Month at the Large Igneous Provinces website)

Adel Mountain Volcanics, Montana