Facies and Architecture of the Lezonabar Member, Higuer-Getaria Formation, Errentzun Zabal, Spain
D. M. Hodgson, R. Wild, 2008. "Facies and Architecture of the Lezonabar Member, Higuer-Getaria Formation, Errentzun Zabal, Spain", Atlas of Deep-Water Outcrops, Tor H. Nilsen, Roger D. Shew, Gary S. Steffens, Joseph R. J. Studlick
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Late Cretaceous-Eocene deep-water deposits of the Guipúzcoa basin are well exposed along the Basque coastline. Early Eocene deposits provide an opportunity to analyze the facies distribution and architecture of a thick-bedded, sand-rich, turbidite system, a commonly identified seismic facies. The Guipúzcoa basin is a narrow east-southeast-to-west-northwest-trending foreland basin that formed during the Cretaceous and Eocene. Sediment was supplied to deep-water settings via the Aquitanian basin in the northeast and the South Pyrenean foreland basin in the southeast. In the late Cretaceous and Paleocene, the shelf area was largely covered with carbonate platforms, and turbidity currents transported carbonate-rich sediment into the deeper parts of the basin. The deep-water sediment supply changed through early Eocene times to a siliciclastic-rich system, and the stratigraphy comprises a series of prograding submarine-fan systems. The deposits change upward from thin beds to sheets to channels. Three sedimentary cycles have been identified that successively increase in their proportion of siliciclastic material, average grain size, and bed thickness. The uppermost cycle, the only cycle dealt with in this paper, is the Higuer-Getaria Formation, which is exposed between Hondarribia and San Sebastian (Figure 1). Seven higher order cycles have been identified and correlated more than 15 km (9 mi) downdip (Figure 5). In the Higuer-Getaria Formation, 20–80-m (66–262-ft)-thick intervals of thick-bedded, immature, coarse-grained sandstones with widespread amalgamated and dewatered contacts, are separated by 15–40-m (49–131-ft) - thick intervals of thin-bedded turbidites that preserve a wide diversity of ichnofauna. Updip, bottom currents are interpreted to have reworked the thin-bedded turbidite bed-tops
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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