- Usage in publication:
-
- Contreras Conglomerate Member*
- Modifications:
-
- Named
- Dominant lithology:
-
- Conglomerate
- AAPG geologic province:
-
- Basin-and-Range province
Summary:
Named as middle member of Pitoikam Formation. Type locality is on unnamed wash nearly a mi north of Peak 6164, west-central part of Baboquivari Mountains, Papago Indian Reservation, Pima Co, AZ in the Basin-and-Range province. Forms the crest of the Baboquivaris at head of Fresnal Wash. Forms steep slopes trenched by narrow ravines and littered with boulders. Most of the coarse beds are thick--up to 20 ft--predominately of boulders and beds 6 inches thick of sandstone and mudstone. The conglomerate fragments coarse sand- to boulder-size in an arkosic matrix of pea-size gravel are almost entirely pinkish quartz latite porphyry. As much as 4,400 ft thick. Mapped (geologic map) in east part of T18S, R9E and west part of T18S, R8E. Overlies lower conglomerate member. Overlain by Chiltepines Member (named) of Pitoikam. Is assigned a Mesozoic? age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Contreras Conglomerate Member*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Basin-and-Range province
Summary:
Age refined to Early Jurassic.
Source: GNU records (USGS DDS-6; Denver 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 ([ ]).