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Title: Recognition of foraminifers in petrographic thin section, Monterey Formation, Santa Maria coast

Conference · · AAPG Bull.; (United States)
OSTI ID:6594909

Foraminifera are often found on petrographic slides of mudstones from the California Neogene, but the lack of a reference for identifying sectioned tests has made it impossible for these observations to yield much information. In a study of coastal outcrops of the Monterey Formation in the Santa Maria basin, this shortcoming was particularly evident, as many of the foraminiferal rocks are highly indurated and the specimens commonly are too eroded and fragile to survive conventional disaggregation procedures. Also, foraminifers encased as nuclei of phosphatic pellets remain obscured in washed residues. In order to overcome these problems, well-preserved specimens from coeval strata elsewhere (e.g., upper Newport Bay, Naples Beach) were isolated, identified, and thin sectioned for comparison with the specimens seen in petrographic slides derived from the Mussel Rock, Lions Head, and Boathouse Beach (Rodeo Canyon) sections. An innovative thin-sectioning technique devised for this analysis has been useful in interpreting foraminiferal assemblages that are not readily extracted from the rocks.

Research Organization:
Chevron Oil Field Research Co., La Habra, CA (USA)
OSTI ID:
6594909
Report Number(s):
CONF-8804144-
Journal Information:
AAPG Bull.; (United States), Vol. 72:3; Conference: AAPG SEPM-SEG Pacific Section and SPWLA annual convention, Santa Barbara, CA, USA, 17 Apr 1988
Country of Publication:
United States
Language:
English