Elevating Geoscience in the Southeastern United States: New Ideas about Old Terranes—Field Guides for the GSA Southeastern Section Meeting, Blacksburg, Virginia, 2014
This volume includes 10 field guides that explore the diverse geology of the southern and central Appalachians. These guides examine both ancient rocks and modern landscape processes, highlighting new research ideas regarding these old terranes. Three guides focus on the geology of the Appalachian Plateau and Valley and Ridge, considering topics such as the enigmatic Eocene igneous rocks, the gas-rich Marcellus and Millboro Shales, and new models for karst formation. The 2011 M5.8 Mineral, Virginia, earthquake literally shook up our understanding of the Piedmont and two guides focus on new research in the epicentral region. Two guides take in the Paleozoic to Proterozoic geology of the Blue Ridge province. The volume is rounded out by three guides focused on Mesozoic geology, including the world-class Lagerst–tte fauna in the Dan River basin, a unique uranium deposit at Coles Hill, Virginia, and the tectonics of the Scottsville Basin.
Stratigraphy, structure, and regional correlation of eastern Blue Ridge sequences in southern Virginia and northwestern North Carolina: An interim report from new USGS mapping
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Published:January 01, 2014
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CiteCitation
Mark Carter, Arthur Merschat, 2014. "Stratigraphy, structure, and regional correlation of eastern Blue Ridge sequences in southern Virginia and northwestern North Carolina: An interim report from new USGS mapping", Elevating Geoscience in the Southeastern United States: New Ideas about Old Terranes—Field Guides for the GSA Southeastern Section Meeting, Blacksburg, Virginia, 2014, Christopher M. Bailey, Lorrie V. Coiner
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Abstract
Examination of key outcrops in the eastern Blue Ridge in southern Virginia and northwestern North Carolina is used to evaluate existing stratigraphic and structural models. Recent detailed mapping along the Blue Ridge Parkway and the eastern flank of the Mount Rogers massif provides the opportunity to (1) evaluate legacy data and interpretations and (2) formulate new ideas for regional correlation of eastern Blue Ridge geology.
Lynchburg Group rocks in central Virginia (metagraywacke, quartzite, graphitic schist, amphibolite, and ultramafic rocks) carry southward along strike where they transition with other units. Wills Ridge Formation consists of graphitic schist, metagraywacke, and metaconglomerate, and marks the western boundary of the eastern Blue Ridge. The Ashe Formation consists of conglomeratic metagraywacke in southern Virginia, and mica gneiss, mica schist, and ultramafic rocks in North Carolina. The overlying Alligator Back Formation shows characteristic compositional pin-striped layers in mica gneiss, schist, and amphibolite.
The contact between eastern Blue Ridge stratified rocks above Mesoproterozoic basement rocks is mostly faulted (Gossan Lead and Red Valley). The Callaway fault juxtaposes Ashe and Lynchburg rocks above Wills Ridge Formation. Alligator Back Formation rocks overlie Ashe and Lynchburg rocks along the Rock Castle Creek fault, which juxtaposes rocks of different metamorphism. The fault separates major structural domains: rocks with one penetrative foliation in the footwall, and pin-striped recrystallized compositional layering, superposed penetrative foliations, and cleavage characterize the hanging wall. These relationships are ambiguous along strike to the southwest, where the Ashe and Alligator Back formations are recrystallized at higher metamorphic grades.
- Appalachians
- Ashe Formation
- Blue Ridge Province
- cleavage
- correlation
- faults
- field trips
- folds
- foliation
- government agencies
- grade
- guidebook
- hanging wall
- interpretation
- lower Paleozoic
- Lynchburg Formation
- mapping
- metamorphism
- models
- Mount Jefferson
- Neoproterozoic
- nomenclature
- North America
- North Carolina
- outcrops
- Paleozoic
- Precambrian
- Proterozoic
- recrystallization
- road log
- sequence stratigraphy
- structural analysis
- survey organizations
- U. S. Geological Survey
- United States
- upper Precambrian
- Virginia
- northwestern North Carolina
- Fries Fault
- southern Virginia
- Alligator Back Formation
- Jefferson Quadrangle
- Blue Ridge Parkway
- Gossan Lead Fault
- Mouth of Wilson Quadrangle
- Callaway Fault
- Laurel Springs Quadrangle
- Rock Castle Creek Fault
- Madwos of Dan Quadrangle
- Whitehead Quadrangle
- Mount Rogers Massif
- Alum Ridge Quadrangle
- Wills Ridge Formation
- Woolwine Quadrangle
- Glendale Springs Quadrangle