VIRGINIA GEOLOGY PHYSIOGRAPHIC PROVINCES MATHEMATICS SCIENCE CENTER Courtesy
- Slides: 45
VIRGINIA GEOLOGY PHYSIOGRAPHIC PROVINCES MATHEMATICS & SCIENCE CENTER
Courtesy of Virginia Division of Mineral Resources
A mile-wide asteroid struck near the mouth of the Chesapeake Bay 35 million years ago. Courtesy of NASA
THE COASTAL PLAIN • A region of sedimentary strata consisting of sands, muds, and gravels • Tidal waters occupy not only the Chesapeake Bay, but also lower portions of the James, York, Rappahannock and Potomac rivers • Extends inland for more than 100 miles and is monotonously flat
Courtesy of Virginia Division of Mineral Resources
THE PIEDMONT • Largest province extending from the Fall Line westward to the Blue Ridge Mountains • comprised of a complex of metamorphic and igneous rocks, overlain in a few places by Triassic-age sedimentary beds • Important rocks and minerals include pegmatites, slate, kyanite, gold and pyrite
Courtesy of Virginia Division of Mineral Resources
The Blue Ridge Mountain • A long narrow, northeast-southwest trending mountain chain • consists of old Precambrian-age sedimentary and volcanic rocks • Old Rag Granite is the oldest rock unit dated in Virginia at 1. 2 billion years • The two highest mountains in the state, Mt Rogers (elevation 5, 719 ft. ) and White Top (elevation 5, 520 ft. ) are both in the southern Blue Ridge
Courtesy of Virginia Division of Mineral Resources
The Valley and Ridge • Composed of folded and faulted 550 to 300 million-year-old sedimentary rocks • Most ridges are held up by resistant sandstone, and most valleys are underlain by less resistant shale, limestone, and dolostone • Karst features, such as caves and sinkholes are common throughout this province
Courtesy of Virginia Division of Mineral Resources
Courtesy of Virginia Division of Mineral Resources
The Appalachian Plateau • Contains deep narrow valleys and steep, rugged mountain sides caused by downcutting by streams • Consists of 320 to 280 million-year-old sandstone and shale with coalbeds • Most of the rock layers are relatively flatlying • Coal is Virginia’s most important mineral resource