Type II Shelf Margin, Høgsnyta, Norway: Attached Slope Turbidite System
Piret Plink-Björklund, Ron Steel, 2008. "Type II Shelf Margin, Høgsnyta, Norway: Attached Slope Turbidite System", Atlas of Deep-Water Outcrops, Tor H. Nilsen, Roger D. Shew, Gary S. Steffens, Joseph R. J. Studlick
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Høgsnyta is one of the l-by-5-km (0.6-by-3.0-mi)-scale mountainside outcrops that expose shelf-margin clinoform complexes in the Eocene Central Basin of Spitsbergen. The shelf-margin clinoforms have been documented in two approximately 30-km (18-mi)- long transects: Grøndalen-Reindalen transect and Van Keulenfjorden transect. The Høgsnyta shelf margin at Reindalen is exposed on a dip-parallel, steep mountainside as a wedge-shaped turbidite sandstone body. It is 70 m (230 ft) thick at the shelf edge, thins downslope, and pinches out above the base of slope, approximately 5 km (3 mi) from the shelf edge. The height of the clinoform complex of approximately 200 m (656 ft) gives a direct estimate for the paleowater depth. The outcrop also exposes older marine mudstones below the studied shelf-margin clinoform complex. The shelf includes younger clinoform complexes, as well as a younger coastal-plain succession above the shelf-margin complex. The Høgsnyta turbidite system is a slope-turbidite apron, attached to a fluvial, shelf-edge delta system. Fluvial distributary channels fed into delta-front sheets or into slope channels; the slope channels terminated with slope lobes on the upper and middle slope, or with turbidite sheets on the lower slope. The internal architecture of the Høgsnyta shelf-margin clinoform complex reflects deposition in a fourth-order sea-level cycle that includes: (1) shelf-margin progradation during the falling stage, (2) lower slope aggradation during the early lowstand, (3) intralowstand flooding back onto the shelf edge, and (4) shelf-margin progradation during the late lowstand. The Spitsbergen data shows that sands were distributed beyond the shelf edge during falling stage
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Tor H. Nilsen, a red-haired Scandinavian who stood more than six feet tall, died October 9, 2005, at his San Carlos, California, home. This was after a valiant five-year fight with melanoma cancer. He was 63. His ashes were scattered at his family plot in Norway in 2006.
He was born in New York City on November 29, 1941, to Mollie Abrahamson and Nils Marius Nilsen of Mandal, Norway, and was the first of their children to be born in the United States. After graduating from Brooklyn Tech, he earned his B.S. in geology from City College of New York in 1962. While there, his prowess on the basketball court impressed a scout from the New York Knicks, but Tor went on to graduate school and earned his M.S. and Ph.D. degrees in geology from the University of Wisconsin at Madison in 1964 and 1967, respectively. His M.S. thesis was a study of Precambrian metasedimentary deposits in the Lake Superior area, and his Ph.D. thesis was a study of Devonian alluvial-fan deposits of the Old Red Sandstone in western Norway.
Dr. Nilsen’s principal expertise was in depositional systems analysis, stratigraphic analysis, and the relationships among tectonics, eustasy, and sedimentation. He began his industry career in 1967 as a research geologist with the Shell Development Company in Houston, Texas, and Ventura, California, where he worked on the tectonics and sedimentation of Tertiary shelf systems of coastal California. He subsequently spent two years with the U.S. Army Corps of Engineers as the Military