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Geologic Unit: Huasna
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  • Usage in publication:
    • Huasna member
  • Modifications:
    • Named
    • Biostratigraphic dating
  • Dominant lithology:
    • Sandstone
    • Claystone
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Hall, C.A., Jr., 1962, Evolution of the echinoid genus Astrodapsis: University of California Publications in Geological Sciences, v. 40, no. 2, p. 47-180.


Summary:

Huasna member named as oldest member (of 3) of Santa Margarita formation in Phoenix-Saucelito Creeks area, south-central part of San Luis Obispo, CA. [Probably named for West Huasna fault or Huasna syncline]. Consists of white to gray-grown quartz arenite or arkosic wacke. In the west there is a siliceous shaly claystone facies. Composite columnar section shows unit is approximately 500 feet thick. Overlies Monterey formation; underlies Phoenix member (new) of Santa Margarita formation. Age is late Miocene based on PECTEN (AEQUIPECTEN) DISCUS Conrad.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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