Structure, Petrology, and Paleomagnetism

• Paleomagnetism/Environmental Magnetism
• Mineralogy and Petrology
• Structure

Paleomagnetism/Environmental Magnetism

Magnetic properties of iron oxides found in naturally occurring sediments have been shown to reflect changes in environmental processes operating on the Earth's surface. Research in the state-of-the-art Environmental Magnetism Lab is focused on the application of magnetism to understanding these global environmental processes. Much of our work is concentrated on investigating sediments from loess sequences and caves in the Czech Republic as well as local sediments from Lake Superior and lakes from the Keweenaw. More traditional research in rock and paleomagnetism cuts across many disciplines within the department so our students can work toward degrees in either geophysics or geology.

We have ongoing projects to determine the effects of alteration on magnetic properties of the oceanic crust, to investigate the magnetic properties of tephra, to evaluate landslide potential on volcanic islands such as Hawaii, and to decipher the details of apparent wander to gain insight into the relative motion of lithospheric plates, and to understand geomagnetic field behavior. Our laboratory is equipped with a fully automated 2G Superconducting Rock Magneto meter housed in a magnetically shielded room(ambient field < 500 nT), a vibrating sample magnetometer, a spinner magnetometer, susceptibility bridges, thermal and alternating field demagnetization equipment, and field equipment.

Research Grants
National Science Foundation, $129,000, 7/15/98 - 6/30/00, Acquisition of a Superconducting Rock Magnetometer and a Field-Free Room, $209,00 MTU cost-share, J. F. Diehl and S. Beske-Diehl.

National Science Foundation, $71,894, 5/1/97 - 5/31/00, Magnetic susceptibility variations in cave sediments from the Moravian Karst, Czech Republic: A record of environmental change?, J. F. Diehl.
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Mineralogy and Petrology

Mineralogical research centers on the world class A. E. Seaman Mineral Museum (include a link to the museum's web page) on campus. This research includes characterization of new mineral species as well as descriptive mineralogy and the paragenesis of both classic and new mineral occurrences. Current work centers on the mineralogy of Canada's Grenville Province and the St. Lawrence Lowlands of northern New York State, and includes investigations on naturally occurring spherical graphites, and lead and other hydrothermal vein minerals. Research in clay mineralogy has covered a wide range of topics including:

1) Modern sediments in Lake Superior, as part of a multi- departmental investigation into the origin of the Keweenaw Current and its impact on sediment dispersal in the lake;

2) Clay diagenesis in petroleum fields (Gulf Coast, North Sea, and Michigan);

3) Layer silicates in ore deposits and the White Pine copper sulfide deposits;

4) Clay minerals in geothermally altered volcanic and sedimentary rocks; and

5) Identification of clay minerals in soils as part of geological engineering site investigations.

Many of the clay mineral investigations are part of larger mineralogical and petrological investigations into sedimentary diagenetic systems, as well as geothermal systems and ore deposits. These investigations utilize a wide range of tools including Optical Microscopes, Scanning and/or Transmission Electron Microscopes, Electron Microprobe, and X-ray Fluorescene Analyzers, as well as a very well- equipped Petrographic Image Processing facility. Most investigations in Metamorphic Petrology have emphasized low-grade metamorphism in sedimentary and volcanic rocks. Most Igneous Petrology is a component of volcanic hazards investigations, to establish the past history and eruptive style of volcanoes under investigations. Petrologic research is also a major component of field investigations of Precambrian metamorphic, plutonic, and fold and thrust belts of the Great Lakes region.

Structure

Studies in structural geology involve microscopic to tectonic scale investigations in the field, augmented with laboratory work. In the masters program, thesis typically involve field mapping of Penokean and Keweenawan age Precambrian rocks that have complex structural histories. These upper Michigan projects typically consist of a few kilometers of river section containing polyphase fold structures and foliations and complex fault development. In some cases, when markers are available, measurements of finite strain are correlated with the structural history. Numerous structural problems remain in the proterozoic belts, including thrusting relationships in the cover rocks and details of basement deformation.
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