Deposits of the Creede Caldera, Colorado
The Creede Formation was deposited within closed basin(s) of the Creede caldera (26.4 Ma) moat after structural resurgence of Snowshoe Mountain. Sedimentary facies consist of (1) fanglomerates on the caldera walls and resurgent dome, including a large paleoalluvial fan within the Creede Mining District; (2) interbedded sandstones, siltstones, and travertine beds of the lacustrine deposits; (3) massive travertine bodies; and (4) bedded tuff horizons. Provenance of the clastic rocks is the caldera walls, resurgent dome, and intracaldera lavas. Intracaldera volcanism and travertine deposition were continuous throughout deposition of the Creede Formation. Clastic rocks are all tuffaceous, and interbedded tuffs are common. Most of the Creede Formation was deposited after structural resurgence. Many travertine fissure ridges are located at the hinge line of the resurgent dome, suggesting that low-temperature hydrothermal activity began after resurgence. We propose that the original thickness of the Creede Formation was not much greater than it is at present and that some of the original depositional surfaces may be preserved. Diagenetic minerals in the tuffaceous clastic rocks and bedded tuffs of the Creede Formation include opal, smectite, clinoptilolite, heulandite(.), analcime, and K-feldspar. Rocks with a vitric ash component occur in some peripheral moat locations. Preliminary interpretation of mineral distribution suggests that diagenetic alteration of the moat sedimentary rocks took place in a closed-basin, saline, alkaline lake(s) environment.
- Research Organization:
- Los Alamos National Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6365229
- Report Number(s):
- LA-10943-MS; ON: DE87014709
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intracaldera volcanism and sedimentation - Creede Caldera, Colorado
Origin and paleoenvironmental significance of calcite pseudomorphs after ikaite in the Oligocene Creede Formation, Colorado
Related Subjects
CALDERAS
GEOLOGIC HISTORY
COLORADO
GEOLOGIC DEPOSITS
DIAGENESIS
MINERALOGY
SEDIMENTARY ROCKS
TRAVERTINE
TUFF
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE ROCKS
CARBONATES
FEDERAL REGION VIII
LIMESTONE
NORTH AMERICA
OXYGEN COMPOUNDS
ROCKS
USA
580100* - Geology & Hydrology- (-1989)