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Recent geophysical and geological research in Antarctica related to the assessment of petroleum resources and potential environmental hazards to their development

During the 6-year negotiation of and adoption of the Convention on the Regulation of Antarctic Mineral Resources Activities on June 2, 1988, various countries have increased their attention to the possibility of exploitation of Antarctica's petroleum resources, which are covered by this treaty. However, there are no known petroleum resources in Antarctica, and scientific information is lacking to
Authors
John C. Behrendt

Small domes on Venus: Probable analogs of Icelandic lava shields

On the basis of observed shapes and volumetric estimates, we interpret small, dome-like features on radar images of Venus to be analogs of Icelandic lava-shield volcanoes. Using morphometric data for venusian domes in Aubele and Slyuta (in press), as well as our own measurements of representative dome volumes and areas from Tethus Regio, we demonstrate that the characteristic aspect ratios and fla
Authors
James B. Garvin, Richard S. Williams

Integration of COCORP deep reflection and magnetic anomaly analysis in the southeastern United States: Implications for origin of the Brunswick and East Coast magnetic anomalies: Alternative interpretation and reply

Integration of magnetic anomaly analysis with COCORP deep reflection data from the southeastern United States provides three new constraints on the interpretation of the Brunswick and East Coast magnetic anomalies, as well as on the reflection data. These are as follows. (1) The source of the Brunswick anomaly lies within the deep crust. This anomaly is not caused by a Mesozoic rift basin, as prop
Authors
Deborah R. Hutchinson, Kim D. Klitgord, Anne M. Tréhu, John H. McBride, K. D. Nelson

Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons

Florida Canyon, one of a series of major submarine canyons on the southwestern edge of the Florida Platform, was surveyed using GLORIA, SeaBeam, and Deep-Tow technologies, and it was directly observed during three DSRV Alvin dives. Florida Canyon exhibits two distinct morphologies: a broad V-shaped upper canyon and a deeply entrenched, flat-floored, U-shaped lower canyon. The flat- floored lower c
Authors
Charles K. Paull, Fred N. Spiess, Joseph R. Curray, David C. Twichell

Early Cretaceous shelf-edge deltas of the Baltimore Canyon Trough: principal sources for sediment gravity deposits of the northern Hatteras Basin

We present evidence that the principal sources for Early Cretaceous (Berriasian-Valanginian) gravity-flow deposits of the northern Hatteras Basin were three large shelf-edge deltas located along the outer margin of the Baltimore Canyon Trough, ∼ 100 km southeast of Cape Charles, Virginia, Ocean City, Maryland, and Long Branch, New Jersey. Sedimentary detritus from the central Appalachian highlands
Authors
C. Wylie Poag, B. Ann Swift, John S. Schlee, Mahlon M. Ball, Linda L. Sheetz

Chronostratigraphic relations of neogene formations of the Great Hungarian Plain based on interpretation of seismic and paleomagnetic data

No abstract available.
Authors
G. Pogacsas, L. Lakatos, E. Simon, G. Vakaros, G. L. Varkonyi, P. Varnai, Aron Jambor, T. Hamar, M. Lantos, Robert E. Mattick, Donald P. Elston

Origin, structure, and evolution of a reattachment bar, Colorado River, Grand Canyon, Arizona

In a channel expansion, flow can separate from the bank, creating a zone of relatively weak recirculating current. Bars that accumulate in this weak flow near the point where flow reattaches to the bank are called reattachment bars. As a reattachment bar evolves, the recirculation zone may fill with sediment and restrict flow from the main channel. The increasingly restricted flow over the bar cau
Authors
David M. Rubin, John C. Schmidt, Johnnie N. Moore

Flume experiments on the alignment of transverse, oblique, and longitudinal dunes in directionally varying flows

For more than a century geologists have wondered why some bedforms are orientated roughly transverse to flow, whereas others are parallel or oblique to flow. This problem of bedform alignment was studied experimentally using subaqueous dunes on a 3–6-m-diameter sand-covered turntable on the floor of a 4-m-wide flume.   In each experiment, two flow directions (relative to the bed) were produced
Authors
David M. Rubin, Hiroshi Ikeda

Major off-axis hydrothermal activity on the northern Gorda Ridge

The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSV Sea Cliff. The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear ridge at mid-
Authors
Peter A. Rona, Roger P. Denlinger, M. R. Fisk, K. J. Howard, G. L. Taghon, Kim D. Klitgord, James S. McClain, G. R. McMurray, J. C. Wiltshire

Impact assessment of exploratory wells offshore South Florida

No abstract available
Authors
Eugene A. Shinn, Barbara H. Lidz, Phillip A. Dustan

High-energy carbonate-sand accumulation, the Quicksands, southwest Florida Keys

High-resolution seismic-reflection profiles of the Quicksands, located along a broad ridge on the platform shelf west of Key West, Florida, indicate a significant deposit of non-oolitic carbonate sand occurs in a belt 47 km long by 28 km wide. The surface of the belt is ornamented by large (5 m), migrating tidal bars, oriented in a north-south direction, on which sand waves, oriented in an east-we
Authors
Eugene A. Shinn, Barbara H. Lidz, Charles W. Holmes

A numerical study of some potential sources of error in side-by-side seismometer evaluations

This report presents the results of a series of computer simulations of potential errors in test data, which might be obtained when conducting side-by-side comparisons of seismometers. These results can be used as guides in estimating potential sources and magnitudes of errors one might expect when analyzing real test data. First, the derivation of a direct method for calculating the noise levels
Authors
L. Gary Holcomb