--> Stratigraphic Sequence Architecture of Deep-Sea Clastic System From Aerial Photographs, Great Valley Sequence, Northern California, by Rosemary C. Paramore and Robert K. Suchecki; #91024 (2010)

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Stratigraphic Sequence Architecture of Deep-Sea Clastic System From Aerial Photographs, Great Valley Sequence, Northern California

Rosemary C. Paramore, Robert K. Suchecki

Lineations interpreted from aerial photographs reveal stratal geometries of deep-sea clastic deposits along an ancient basin margin that was strongly influenced by both subduction and related volcanogenic processes. These stratal patterns of four principal stratigraphic sequences in steeply dipping Tithonian to Valanginian sediments of the Great Valley sequence, northern California, in combination with lithic facies data, illustrate the major components and internal architecture that resulted from eustatic and tectonic variations.

Consistently repetitious sequences, which were deposited seaward of the ancient shelf edge, contain the following components. (1) Basal, mounded sand-shale accumulations that have bidirectional downlap of internal strata. These accumulations are up to 250 m thick and 1.25 km lateral extent in outcrop. (2) Clinoformal wedges of topographically conspicuous conglomerate and sandstone that contain prominent internal downlapping and toplapping strata. Locally, at the top of these wedges are stratal geometries that mimic inferred levee-channel complexes. This stratigraphic component is up to 1.1 km thick and has minimum lateral extent of 15 km. (3) Multiple prograding, clinoformal wedges with characteristic downlapping and toplapping internal strata. These are composed dominantly of mudston and thin-bedded sandstone-turbidite successions and have up to 2 km cumulative thickness in a single sequence.

Although deposited along a tectonically active margin, the component geometries and internal stratal patterns of the sequences are similar in detail to seismically defined stratigraphic sequences of Vail. The integration of fine-scale stratal architecture based on aerial photograph interpretation and sediment facies using classical models of submarine-fan deposits illustrates the depositional and stratigraphic evolution of a convergent deep-sea margin.

AAPG Search and Discovery Article #91024©1989 AAPG Pacific Section, May 10-12, 1989, Palm Springs, California.