Inner shelf storm-surge deposits of Late Cretaceous Chico Formation, northeastern Sacramento Valley, California
The early Campanian Tenmile Member of the type Chico Formation, northeastern Sacramento Valley, California, consists of 325 m of inner shelf sediments deposited by storm surge events. Storm deposits are represented by fine-grained sandstone beds 30-180 cm thick (mean = 120 cm) with a characteristic internal sequence of structures. Erosional bases are overlain by lensoidal shell lags which are in turn overlain by hummocky to swaley cross-stratified sand in the upper part of the beds, and bioturbation generally increases upward within a bed. In complete sequences, a unit of mudstone within wave-rippled sand laminae is present at the top of the bed. This sequence of structures corresponds to a change form high-energy to low-energy conditions during a single storm event. Common variations from the ideal sequence include a lack of basal shell lags, intensive bioturbation through most of the bed, or absence of a mudstone unit, resulting in amalgamation of beds.
- Research Organization:
- California State Univ., Chico
- OSTI ID:
- 6533675
- Report Number(s):
- CONF-870606-
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 71:5; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
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