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Bathysiphon (Foraminiferida) at Pacheco Pass, California: A Geopetal, Paleocurrent, and Paleobathymetric Indicator in the Franciscan Complex

Saja, D.B., Pfefferkorn, H.W., Phipps, S.P.
2 009
We document a new locality for the foraminiferid Bathysiphon at Pacheco Pass, California, a classic blueschist-facies location on the eastern edge of the Franciscan Complex. The nearly featureless, silicified tubes of Bathysiphon cf. aaltoi Miller, 1986 described here are the largest reported from the Franciscan Complex; they are <153 min long and easily recognized in the field. The rarity of fossils in the Franciscan Subduction Complex has hindered field mapping and, thus, a better understanding of its stratigraphy and structure. Bathysiphon specimens can be used as geopetal indicators, since they occur parallel to bedding at the top of argillaceous layers, as paleocurrent indicators (showing a SSE trend at Pacheco Pass), and as paleobathymetric indicators, suggesting, by their large size, mid-to-lower bathyal depths (2000-4000 m).
EES Authors: 
David Saja (1999)
Hermann W. Pfefferkorn
Steve Phipps
Research Track Category: 

Department of Earth and Environmental Science / University of Pennsylvania, 251 Hayden Hall, 240 South 33rd Street, Philadelphia, PA 19104-6316