Potential contributions of metamorphic petrology studies in an ultra-deep drillhole in the southern Appalachians

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6273528

Speer, J A

The proposed, ultra-deep hole in the southeast U.S. will penetrate allochthonous, medium- to high-grade metamorphic rocks of the Inner Piedmont and Blue Ridge thrust sheets. It is anticipated that the hole will then encounter autochthonous low-grade, metasedimentary cover rocks before bottoming out in crystalline Precambrian basement rocks. Metamorphic petrology in the recent past has concentrated on unraveling the physical and chemical history (P, T, X/sub fluid/, etc.) of metamorphic rocks. The techniques that have been developed are ideally suited to the study of relatively limited samples from drill core. Detailed studies of the allochthonous and autochthonous rocks from the drillhole, combined with comparable studies of the surface rocks, by metamorphic petrologists experimented with these approaches, would give a 3-dimensional picture of the PTX evolution in the region of the ultra-deep hole, and thus an idea of the geometrical, chemical, and physical changes the rocks experienced. This would place constraints on conditions of the rocks before and after thrusting and thus any tectonic models of thrusting in the southern Appalachians. With limited sampling this could be a problem, with more complete sampling it will be an advantage. The metamorphic petrology of the rocks will provide basic support for the other studies of the drill core and drillhole, most notably geochronology and stable isotopes. It should not be forgotten that in addition to the historical metamorphism, the expected, present-day conditions in the drillhole are those of burial metamorphism. The hole will present an excellent opportunity to study such active metamorphic conditions.

• Research Organization: Virginia Tech., Blacksburg (USA)
• OSTI ID: 6273528
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
AGE ESTIMATION
BOREHOLES
CAVITIES
CHEMICAL PROPERTIES
CHEMISTRY
EXPLORATORY WELLS
FEDERAL REGION III
FEDERAL REGION IV
GEOCHEMISTRY
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
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METAMORPHIC ROCKS
METAMORPHISM
NORTH AMERICA
NORTH CAROLINA
PETROGENESIS
PETROLOGY
PHYSICAL PROPERTIES
ROCKS
USA
VIRGINIA
WELLS