Roger D Shew, 2008. "Channel Architectures and Associated Facies in the Brushy Canyon and Cherry Canyon Formations, Guadalupe Mountains Area, Texas, USA", Atlas of Deep-Water Outcrops, Tor H. Nilsen, Roger D. Shew, Gary S. Steffens, Joseph R. J. Studlick
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The west Texas and southeast New Mexico area contains several basins and surrounding platforms that formed and evolved during the Carboniferous and Permian. The collision of Gondwana with Laurasia led to the Ouachita and Marathon orogenies that formed the small intracratonic foreland basins that include the Delaware basin. The Delaware basin is rimmed by a carbonate ramp that evolved into a carbonate platform; it contains thick carbonate and evaporite and thin siliciclastic deposits. The basin is dominated by thick sandstones and siltstones with minor, fine-grained carbonate mudstones and very fine-grained siltstones separating the more sand-rich intervals. Deposition was strongly controlled by sea level fluctuations (glacially controlled eustatic cycles); highstand deposits are dominated by carbonates and lowstand deposits are dominated by siliciclastics. Fine-grained siltstones, with minor shales, are also the background sediments in the basin, particularly during the deposition of the Brushy and cherry Canyon Formations. The Brushy Canyon, formed during a major third-order lowstand cycle with exposure of the carbonate ramp/evolving shelf, is dominated by basinal sandstone deposition. It has been divided into the lower, middle, and upper Brushy Canyon. These probable fourth-order cycles also contain numerous fifth-order cycles. The cherry Canyon Formation is dominated by siltstone deposits. A notable exception is at Last chance Canyon, located near Sitting Bull Falls, which was a feeder canyon supplying coarser grained, high net-to-gross (N/G) sands and silts to the basin. Three outcrops are shown on the following pages that illustrate three distinct channel architectures: single channel (cut-aggrade-abandon), multiple channels (cut-drape-fill), and nested channels with single and amalgamated channels. Contributions from Beaubouef et al., O’Byrne et al., and Barton et al. (chapters 105, 108, 109, this volume) show other channel architectures and facies from the Brushy Canyon Formation.
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Atlas of Deep-Water Outcrops
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