Evolution of the Lower Tertiary Elko Lake Basin, a Potential Hydrocarbon Source Rock in Northeast Nevada

摘要

1. The Eocene Elko Formation appears to be entirely younger than the Eocene Green River Formation and it is very likely that the Elko Lake(s) did not form until Lake Uinta was completely filled in. 2. The Elko Lake probably formed during a period of regional extension, whereas the Green River lakes formed during an earlier period of regional compression (Laramide orogeny). 3. The rich oil shale interval in the Elko was deposited immediately after the onset of volcanism in the area, suggesting that the input of volcanic material to the lake may have initiated a period of high organic productivity. 4. The organic matter in the Elko is distinctive from that of the Green River oil shale in that it (1) is less dominated by type I kerogen in much of the oil shale and therefore (2) produces more gas and less oil per unit organic carbon.