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Your search keyword '"John R. Henderson"' showing total 143 results
Start Over Author "John R. Henderson" Publication Year Range More than 50 years ago
143 results on '"John R. Henderson"'

1. Tectonic significance of minor structures in Conococheague Formation near Lancaster, Pennsylvania

Author

John R. Henderson

Subjects
Lineation, Transverse plane, Tectonics, Plane (geometry), Dolomite, Foliation (geology), General Earth and Planetary Sciences, Petrology, Flattening, Geology
Abstract

Conococheague limestone and dolomite beds form small scale noncylindrical recumbent folds with homoaxial mineral lineations (L9) on a semipenetrative axial plane foliation (S l ). Large scale recumbent folds are noncylindrical and nonplanar, but mineral lineations remain homoaxial on the scale of the area mapped. Analysis of a deformed oolite bed indicates that the rocks have undergone three-dimensional strain involving constriction. S l and L9 mark the principal flattening plane and elongation direction; small folds may have originated by simultaneous buckling in two principal strain directions.

Published
1969
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7. Airborne geophysical study in the pensacola mountains of antarctica

Author

John R. Henderson, John C. Behrendt, and Laurent Meister

Subjects
geography, Multidisciplinary, geography.geographical_feature_category, biology, Crust, STREAMS, biology.organism_classification, Ice shelf, Mantle (geology), Paleontology, Neptune, Glacial period, Magnetic anomaly, Pensacola, Geology
Abstract

A seismic reflection, gravity, and aeromagnetic reconnaissance was made in the Pensacola Mountains, Antarctica, during the 1965-66 austral summer. Prominent ice streams located between the Neptune and Patuxent Ranges and east of the Forrestal Range overlie channels in the rock surface 2000 meters below sea level which are probably of glacial origin. Seismic reflections show that the Filchner Ice Shelf is 1270 meters thick near its southern margin. Along the boundary between West and East Antarctica, Bouguer anomalies decrease from +60 milligals in West Antarctica to -80 milligals in East Antarctica. An abrupt change in crustal structure across this boundary is required to explainl the 2 milligals per kilometer gradient. This may indicate a fault extending through the crust into the mantle. Aeromagnetic profiles delineate anomalies up to 1800 gamma associated with the basic stratiform intrusion which comprises the Dufek and Forrestal ranges. A probable minimum area of 9500 square kilometers is calculated for the intrusive body on the basis of the magnetic anomalies, making it one of the largest bodies of its type. The extension of this magnetic anominaly across a fault forming the north border of the Pensacola Mountains probably precludes transcurrent movement.

Published
1966

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