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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 957

Last Page: 957

Title: Microfossils from Type Relizian and Luisian Stages of California: ABSTRACT

Author(s): Kristin McDougall, R. Z. Poore, John A. Barron

Article Type: Meeting abstract


Kleinpell designated the strata of the Monterey Formation in Sec. 28, T28S, R14E, as the type locality of the Luisian Stage. Microfossils from this section, however, were never described; instead, the Luisian Stage was characterized by foraminiferal faunas in strata from Reliz Canyon that overlie strata of the type Relizian Stage. The two Relizian and three Luisian Zones described by Kleinpell can be recognized in the benthic foraminiferal faunas from recently collected samples from Reliz Canyon. This sequence of zones cannot be recognized in benthic foraminiferal faunas of the type Luisian section or in the nearby Wilson's corner section, partly because the Reliz Canyon faunas represent deeper and more diverse faunas than those from the type Luisian area.

In the Reliz Canyon section, benthic foraminiferal faunas diagnostic of the Saucesian-Relizian boundary coincide with the base of the Helicosphaera ampliaperta Zone. The Relizian-Luisian boundary as indicated by the benthic foraminifers occurs near the H. ampliaperta-Sphenolithus heteromorphus boundary. Poor preservation and limited exposures prevent a more definitive calibration. Occurrence of late Luisian benthic foraminifers with meager floras containing Cyclogargolithus floridanus suggests an age no younger than the lower part of the Discoaster exilis Zone. In the type Luisian section, benthic foraminifers diagnostic of the Luisian Stage occur both above and below strata designated by Kleinpell as type Luisian. Nannofossil floras in the lower part of the type section are indicativ of the S. heteromorphus Zone and diatoms diagnostic of the Denticulopsis lauta Zone and the lowermost part of the D. hustedtii-D. lauta Zone also are present. Sparse radiolarian faunas are dominated by long-ranging species, typical of present-day California-current faunas.

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