Sedimentology of Muddy Creek Formation, southern Nevada: fluvial-lacustrine basin-fill deposition in Basin and Range province
The Muddy Creek Formation provides a unique three-dimensional exposure of a post-tectonic basin-fill deposit in the Basin and Range province. This Miocene-Pliocene sequence is exposed in Meadow Valley Wash north of the Lake Mead region in southern Nevada. Exposure of basin deposits is excellent because of effects of downcutting in the Colorado/Virgin River drainage systems. Muddy Creek grades laterally from coarse-grained facies at the basin margin to medium to fine-grained fluvial facies and ultimately to fine-grained marginal-transitional lacustrine facies in the basin axis. Basin margin facies consist of conglomerate and eolian sandstone. Lacustrine facies represent vertically aggrading sequences whereas transitional basin margin facies aggrade laterally, with fine-grained sediments onlapping the basin-bounding ranges. Paleocurrent and petrologic evidence, such as the presence of abundant quartz, frosted grains, volcanic fragments, and petrified wood, indicate the principal source for the Muddy Creek sediments was the Triassic Moenkopi and Chinle Formations and Cretaceous/Tertiary volcanics located at the north end of Meadow Valley Wash. The Muddy Creek Formation is an unfaulted, undeformed sequence indicating deposition occurred after cessation of Basin and Range faulting. Further evidence for a post-tectonic origin is that basin facies do not show lateral shifts that would be expected in a tectonically active extensional basin. Drainage patterns, therefore, appear to be essentially unchanged over the last 8 m.y. This study indicates that facies shifts rather than vertical successions alone may be the best gauge of syn-tectonic vs. post-tectonic origin for basin deposits.
- Research Organization:
- Univ. of Kansas, Lawrence (USA)
- OSTI ID:
- 5880802
- Report Number(s):
- CONF-890404-
- Journal Information:
- AAPG Bull.; (United States), Journal Name: AAPG Bull.; (United States) Vol. 73:3; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Neogene paleogeography of western Snake River plain, Idaho and Oregon
Reconstructing normal fault systems with synextensional lacustrine sediments: Examples from northeast Nevada
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
CENOZOIC ERA
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
MESOZOIC ERA
NEVADA
NORTH AMERICA
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEDIMENTATION
TECTONICS
TERTIARY PERIOD
TRIASSIC PERIOD
USA