Interior Western United States
The GSA Annual Meeting in Salt Lake City provided a large and diverse terrain for field trips—from the Basin and Range to the Rocky Mountains, from the Snake River Plain, across the Colorado Plateau, to the Mojave Desert. This volume contains 22 field trip articles, nearly all of those run at the 2005 meeting. All combine the latest research with useful road logs to spectacular and often classic geologic settings. The regional tour has a core of structure and stratigraphy-paleontology contributions, and is rounded off with volcanic, glacial, lacustrine, fluvial geomorphology, neotectonic, geologic hazard, and geoarchaeology articles.
Recognition and interpretation of isolated shelf turbidite bodies in the Cretaceous Western Interior, Book Cliffs, Utah
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Published:January 01, 2005
Abstract
Marine mudstone-encased, inner shelf sandstone bodies are concentrated in a 70–90-m-thick interval that spans the upper Aberdeen and lower Kenilworth members (Blackhawk Formation, Campanian), Book Cliffs, eastern Utah. These sandstone bodies contain a complex mixture of event beds including wave or storm-modi-fied turbidites, hummocky cross stratified sandstones, hyperpycnites, and/or classical turbidites. The turbiditic channel-fills and lobes were deposited below fair weather wave base and are detached from their time equivalent shoreface deposits. Shallow marine facies models should be revised to include turbiditic-rich channels and lobes in some inner shelf settings. A three-component shoreface-to-shelf model, consisting of delta front deposits, subaqueous channels, and prodelta turbidites, is proposed to explain the depositional setting and environment of the Mancos Shale–encased sandstone bodies. Oceanic- or river-flood induced hyperpycnal flows were responsible for cutting a network of subaqueous channels on the inner shelf and for transporting fine-grained sediments from the shoreface to the inner shelf. Other Mancos Shale–encased isolated sandstone bodies in eastern Utah and western Colorado should be reexamined in the light of the new data and models presented herein.
- Blackhawk Formation
- Book Cliffs
- clastic rocks
- Colorado Plateau
- Cretaceous
- depositional environment
- field trips
- Grand County Utah
- Mancos Shale
- Mesaverde Group
- Mesozoic
- North America
- paleoenvironment
- parasequences
- planar bedding structures
- road log
- sand bodies
- sandstone
- sedimentary rocks
- sedimentary structures
- sequence stratigraphy
- turbidite
- United States
- Upper Cretaceous
- Utah
- Western Interior
- Kenilworth Member