- Usage in publication:
-
- Lucia shale
- Modifications:
-
- Named
- Biostratigraphic dating
- Dominant lithology:
-
- Mudstone
- Shale
- AAPG geologic province:
-
- California Coast Ranges province
Summary:
First used by author in abstract (1941) [where type locality designated in upper Reliz Canyon, NE/4 sec. 34, N/2 sec. 35, SE/4 sec. 26, T20S R6E, Junipero Serra 15' quad, Monterey Co., CA]. Crops out in western and southern portions of Los Vaqueros Valley region. Consists of 150 to 500 feet of greenish-gray to steel-gray, thin-bedded nodular mudstone and shale; uppermost 70 feet is maroon mudstone with intercalated thin sandstone beds. Is gradational with both overlying The Rocks sandstone and underlying Junipero sandstone (both new). Foraminifers which occur throughout unit indicate middle Eocene age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Lucia Mudstone Member*
- Modifications:
-
- Adopted
- Revised
- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- California Coast Ranges province
Summary:
Lucia Shale of Thorup (1943) reduced in rank and adopted as Lucia Mudstone Member (2nd from lowermost) of Reliz Canyon Formation. Described as olive-gray silty mudstone with local thin- to thick-bedded graded sandstone. Locally contains abundant planktic foraminifers of early Eocene age and middle to lower bathyal benthonic foraminifers of Ulatisian age (Durham, 1963; Dickinson, 1965; Poore and others, 1977). Is early and middle Eocene age.
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 ([ ]).