AN EOCENE “GORGE” IN THE NORTHERN SACRAMENTO VALLEY, CALIFORNIA1
Published:January 01, 1984
J. O. Frick, T. P. Harding, A. W. Marianos, 1984. "AN EOCENE “GORGE” IN THE NORTHERN SACRAMENTO VALLEY, CALIFORNIA", Paleogene Submarine Canyons of The Sacramento Valley, California, Alvin A. Almgren, Paul D. Hacker
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A prominent erosion and fill feature has been observed in the subsurface of the Sacramento Valley in Northern California. The feature, which has been termed a “gorge”, extends for approximately 65 km along a narrow, sinuous trend that is generally parallel to the course of the Sacramento River.
As much as 600 m of Upper Cretaceous deltaic sediments have been removed by erosion and the trough later filled with sediments that have been correlated with the Eocene B-2 through B-4 Zones of Laiming (1940, 1943).
It is suggested that submarine erosion was initiated by the uplift of adjacent land areas with consequent rejuvenation of the stream. Filling of the trough was started as the sediments built up on the basin floor and the marginal land mass was reduced by erosion. Foraminifera, as well as certain textural features of the sediments, indicate that the entire sequence was laid down in a marine environment. There is no evidence in the fill or in the underlying beds that subaerial processes were involved.
This erosional feature is important for hydrocarbon exploration in that natural gas is present in sediments within the “gorge” as well as being trapped in Cretaceous sediments truncated by the “gorge”.