- Usage in publication:
-
- Rio Guatemala group*
- Modifications:
-
- Named
- Dominant lithology:
-
- Gravel
- Sand
- Silt
- Clay
- Marl
- Limestone
Summary:
Sediments ranging from coarse bouldery gravel through sand, silt, clay, and marl to pure limestone, characterized by rapid lateral changes in lithology and intergrading both horizontally and vertically, are named the Rio Guatemala Group. The San Sebastian Formation represents the first interval of clastic deposition; the Lares Limestone represents biohermal areas; and the Cibao Marl with its Guajataca Member represents the second interval of clastic deposition. Maximum thickness is 700 m. Unconformably overlies Late Cretaceous rocks; conformably underlies Aguada Limestone. Age is Tertiary.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Rio Guatemala Group*
- Modifications:
-
- Revised
Summary:
Mucarabones Sand assigned in the Rio Guatemala Group sharply and conformably over the San Sebastian Formation; grades laterally westward into and intertongues with the Lares Limestone and Cibao Formation. Age is middle Oligocene to early Miocene.
Source: GNU records (USGS DDS-6; Reston 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 ([ ]).