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D. Cummings

Publications and source records attributed to D. Cummings.

2 recordsLinked to original sources

Kink-bands: Shock deformation of biotite resulting from a nuclear explosion

Microscopic examination of granodiorite samples from the shock region around a nuclear explosion reveals sharply folded lens-shaped zones (kink-bands) in the mineral biotite. Fifty percent of these zones are oriented approximately 90 degrees to the direction of shock-wave propagation, but other zones are symmetrically concentrated at shear angles of 50 degrees and 70 degrees to the direction of shock-wave propagation.

Science

Stratigraphy and heavy minerals of the bays formation, Bays Mountain synclinorium, northeast Tennessee

The Bays Mountain synclinorium is in the Valley and Ridge province in northeast Tennessee , southwest of Kingsport and west of Greeneville. The more clastic part of the Bays formation lies in the east section of the synclinorium . The thickness of the Bays decreases from about 870 feet on the east to about 600 feet on the west. Presumably, the red beds and primary features of the Bays formation formed under deltaic conditions. A Camarocladia Zone near its base indicates a time-transgression of the Bays . The Bays is older at the base to the east than at its base to the west. The heavy minerals of the Bays were compared with those of the Cambrian and Precambrian(?) sediments, volcanic rocks, and accessory minerals of the crystalline complex which now comprise the Blue Ridge. The minerals identified include nearly all those in the Cambrian and Precambrian(?) sediments as well as additional minerals not found in these older sediments but that are in the crystalline complex. Such minerals indicate that at least a part of the crystalline complex was above sea level during the Middle Ordovician.

Tennessee