El Paso Formation - a Lower Ordovician platform carbonate deposit
The eastward-transgressive Lower Ordovician El Paso Formation conformably overlies Bliss Sandstone in southern New Mexico. Locally, lower El Paso was deposited on low hills of plutonic and volcanic rocks. The region subsided gradually throughout Canadian time, receiving the El Paso carbonate rock blanket up to 460 m thick. Lithologic and chronologic correlative rocks were deposited over most of the southwestern US as the first Paleozoic carbonate platform sequence. The El Paso Formation contains four members, listed here in ascending order: Hitt Canyon, Jose, McKelligon, and Padre. Gradually decreasing sand content upward through the Hitt Canyon indicates deepening water and/or greater distance to shore. Girvanella(.) oncolites are locally abundant. Stromatolite mounds near the top of the Hitt Canyon, combined with an influx of sand, ooids, and rounded bioclasts in the Jose Member, recorded a shoaling phase. The overlying McKelligon Member contains little or no sand, and sponge-Calathium mounds are prominent at some locales. Stromatolite mounds are interbedded with sponge-Calathium mounds in a few sections. Lower Padre Member beds are typically silty to sandy and locally contain thinly-laminated zones. The Padre contains more restricted fauna that includes traces of ostracods. Pervasive bioturbation of El Paso beds and fauna consisting of echinoderms, sponges, gastropods, trilobites, Nuia, Calathium, cephalopods, and algae plus minor brachiopods and Pulchrilamina indicate predominating shallow-subtidal environments. Low-energy platform environments, in which a large volume of micritic muds accumulated, were disturbed thousands of times by storms producing abundant thin, poorly washed biosparite, intrasparite, and intrasparrudite lenses.
- Research Organization:
- New Mexico State Univ., Las Cruces
- OSTI ID:
- 6443653
- Report Number(s):
- CONF-870606-
- Journal Information:
- AAPG Bull.; (United States), Journal Name: AAPG Bull.; (United States) Vol. 71:5; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Lithostratigraphic correlation of Ellenburger formations and El Paso members from Central Texas to Eastern Arizona
Discriminant analysis of components of El Paso Group rocks in southern Hueco Mountains, Hudspeth County, Texas - approach to depositional environments
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
CARBONATE ROCKS
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
MINERAL RESOURCES
NEW MEXICO
NORTH AMERICA
ORDOVICIAN PERIOD
PALEOZOIC ERA
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
USA