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Geologic Unit: Willows
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Map showing publication footprint
  • Usage in publication:
    • Willows Diorite
  • Modifications:
    • Named
    • Geochronologic dating
  • Dominant lithology:
    • Diorite
  • AAPG geologic province:
    • Santa Maria basin
Publication:

Weaver, D.W., 1969, The pre-Tertiary rocks, IN Weaver, D.W., Doerner, D.P., and Nolf, Bruce, eds., Geology of the northern Channel Islands, southern California borderland: American Association of Petroleum Geologists, Pacific Section, Field Trip Guidebook, [no. 12], p. 11-13, (incl. geologic map, scale 1:24,000)


Summary:

[Probably named for Willows Anchorage] Type area is exposures along Willows Fault north of Willows Anchorage, west Santa Cruz Island, off southern coast of CA. Composed of quartz-hornblende-diorite, hornblende-diorite, hornblendite serpentinized hornblendite, and complimentary dikes of acid and basic rocks. Most is unstrained and very little weathered, and considerably fractured. Is in fault contact with Santa Cruz Island Schist [new]. K-Ar age determination gave 145 +/-5 Ma. Sample collected from upper Laguna Canyon.

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 ( ).

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