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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 47 (1963)

Issue: 9. (September)

First Page: 1770

Last Page: 1770

Title: Subsurface Geology of the Northern San Joaquin Valley: ABSTRACT

Author(s): Otto Hackel, Robert D. Hoffman

Article Type: Meeting abstract

Abstract:

For several years, the Northern San Joaquin Valley has been one of the most active wildcat areas in California. This activity has resulted in the discovery of the McMullin Ranch and Lathrop gas fields and the extension of the Vernalis gas field.

The present extensive exploration continues to be encouraged by several factors among which are a thick marine sedimentary section of variable stratigraphic conditions and relatively low land and drilling costs.

The clastic stratigraphic section consists of continental Plio-Miocene overlying marine Eocene. The Eocene in turn overlies a thick section of marine upper Cretaceous. On the west margin of the basin, the upper Cretaceous rests on lower Cretaceous. Eastward the upper Cretaceous rests on granitic basement. Due to uplift of the "Stockton Arch," the Eocene and some of the upper Cretaceous were eroded from the northernmost portion of the area before deposition of the Continental Plio-Miocene.

Structurally the area has a northwest-southeast grain. From west to east the major features include: (1) the relatively steep outcropping west flank of the basin, (2) the Tracy-Vernalis anticline and fault trend, (3) the central basin syncline, and (4) the long platform-like east flank. The basin plunges south from the cross-trending Stockton Arch fault.

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Copyright 1997 American Association of Petroleum Geologists