thumbnail

Paleogeographic implications of an erosional remnant of Paleogene rocks southwest of the Sur-Nacimiento Fault Zone, southern Coast Ranges, California

Geological Society of America Bulletin

By:
, , ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

A small tract of heretofore-unrecognized Paleogene rocks lies about 30 km northeast of Santa Maria and 1 km southwest of the Sur-Nacimiento fault zone near upper Pine Creek. This poorly exposed assemblage of rocks is less than 50 m thick, lies unconformably on regionally distributed Upper Cretaceous submarine-fan deposits, and consists of three units: fossiliferous lower Eocene mudstone, Oligocene(?) conglomerate, and basaltic andesite that has a radiometric age of 26.6 ?? 0.5 Ma. Both the sedimentary and igneous constituents in the Paleogene sequence are unlike those of known sequences on either side of the Sur-Nacimiento fault zone. The Paleogene sedimentary rocks near upper Pine Creek presumably are remnants of formerly widespread early Eocene bathyal deposits and locally distributed Oligocene(?) fluvial deposits southwest of the fault zone. The 26.6 Ma basaltic andesite, however, may not have extended much beyond its present outcrops. An episode of Oligocene(?) displacement is required by the contrast in thicknesses, depositional patterns, and paleobathymetry of the juxtaposed rock sequences. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Paleogeographic implications of an erosional remnant of Paleogene rocks southwest of the Sur-Nacimiento Fault Zone, southern Coast Ranges, California
Series title:
Geological Society of America Bulletin
Volume
103
Issue:
7
Year Published:
1991
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geological Society of America Bulletin
First page:
941
Last page:
952
Number of Pages:
12