UNDERGRADUATE RESEARCH IN MINERALOGY AT NORTHERN VIRGINIA COMMUNITY COLLEGE: CHARACTERIZATION OF THE CRYSTALLINE BASEMENT ROCK FROM THE BAYSIDE CORE, CHESAPEAKE BAY IMPACT STRUCTURE

Mineralogy students at Northern Virginia Community College (NOVA) have the opportunity to participate in an ongoing research project to help define the geologic and tectonic history of the crystalline basement rock underlying the Atlantic Coastal Plain. In 2001, the USGS recovered granitoid basement rock from a corehole drilled into the annular trough of the Chesapeake Bay Impact Structure at Bayside, VA, approximately five miles from the central crater rim. The USGS classified the rock as a granodiorite, and obtained a SHRIMP U-Pb zircon age of 625 ± 11 Ma. The USGS conducted minimal studies on the Bayside basement rock beyond this initial dating and classification. The USGS has loaned NOVA 26 feet of the core: 12 feet from the bottom of the core, and 14 feet of the uppermost basement. As part of an Honors Option in Mineralogy, NOVA students learn valuable skills in handling core, preparing thin sections, conducting detailed petrographic analyses, including point counting, to specifically characterize their samples. Their cumulative analyses indicate that the rock of this intrusive body is more appropriately classified as granite. Current and future NOVA Mineralogy students will attempt to place the Bayside core intrusive body in a wider geologic context, investigating possible correlations to intrusions of similar age in the Goochland terrane of central VA. This research has also offered NOVA students the invaluable opportunity to present their findings at a variety of meetings and symposia including national and regional GSA meetings, the annual Virginia Geologic Research Symposium, the college Science Seminar and also to local mineral club meetings.