USGS Visual Identifier

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GEOLEX database

Geologic Unit: Laredo

Publication:
Eargle, D.H., 1968, Nomenclature of formations of Claiborne 
   Group, Middle Eocene, coastal plain of Texas, IN Contributions 
   to general geology, 1967: U.S. Geological Survey Bulletin, 
   1251-D, p. D1-D25.
Usage in Publication:
Laredo Formation*

Modifications: Geologic Province: Dominant Lithology:
 Revised
 Gulf Coast basin
 

Summary:
Revised in that Laredo Formation, one of five formations of Claiborne Group, replaces use of Cook Mountain Formation and overlies the newly named El Pico Clay of Claiborne in Rio Grande embayment in the Gulf Coast basin. El Pico was called upper member of Mount Selman Formation (abandoned) in earlier reports. Laredo correlates with the Sparta Sand and Cook Mountain Formations of the Claiborne Group of eastern and central TX. Correlation chart. Cross section. Outcrop areal extent map. Of middle Eocene age.
Source: GNU records (USGS DDS-6; Denver GNULEX).


Publication:
Barnes, V.E., 1976, Geologic atlas of Texas, Crystal City-Eagle 
   Pass Sheet; Dolan Hoye Eargle memorial edition: University 
   of Texas-Austin, Bureau of Economic Geology, 1 sheet, scale 
   1:250,000
Usage in Publication:
Laredo Formation

Modifications: Geologic Province: Dominant Lithology:
 Areal limits
 Overview
 Gulf Coast basin
 

Summary:
Is Eocene formation mapped southwest of Frio River in southwestern Frio, southeastern Zavala, eastern Dimmit, western and central-northern La Salle, and central-northern Webb Cos, TX (Gulf Coast basin). Overlies El Pico Clay (Eocene); overlain by Yegua Formation (Eocene). Is not mapped northeast of Frio River. Correlation of map units shows Laredo correlative with Sparta Sand and Cook Mountain Formation, which are mapped northeast of Frio River. Map unit described as sandstone and clay; thick sandstone member in upper and lower part, very fine to fine grained, in part glauconitic, ferruginous, dominantly red and brown; clay in middle, weathers orange-yellow; thickness 600-700 ft.
Source: GNU records (USGS DDS-6; Denver GNULEX).