Common use of Geology Clause in Contracts

Geology. ▇▇▇▇▇▇▇ Field is located at the northern end of the Santa ▇▇▇▇▇ Valley Basin, about I mile south of San Francisco Bay. The Santa ▇▇▇▇▇ Valley Basin is a Pliocene-age, large, northwest-trending structural depression between the San Andreas and Hayward faults. The basin is bordered on the west by the Santa ▇▇▇▇ Mountains and on the east by the Diablo Range. Regionally, the Santa ▇▇▇▇▇ Valley contains up to 1,500 feet of interbedded alluvial, fluvial, and estuarine deposits (Iwamura, 1980). Locally, these sediments consist of varying combinations of clay, silt, sand, and gravel that represent interfingering of estuarine and fluvial depositional environments during the late Pleistocene and Holocene epochs. The interfingering of fluvial and estuarine sediments in southern San Francisco Bay is related to world-wide fluctuations in sea level during glacial and interglacial episodes of the late Quaternary period (Tetra Tech, 1998c). The fluvial sediments were derived from the Santa ▇▇▇▇ highlands west of the basin and deposited on an alluvial plain bounded by alluvial fan deposits to the west and baylands to the northeast (Iwamura, 1980). Surface geologic maps indicate that alluvial fan deposits extend toward the basin approximately to U.S. Highway 101, which forms the southern boundary of ▇▇▇▇▇▇▇ Field. Shallow deposits on ▇▇▇▇▇▇▇ Field are branching river and flood plain deposits. Estuarine deposits are found at the extreme northern end of ▇▇▇▇▇▇▇ Field.