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rKLE NFELOER <br /> \\� J'Bright People.Righ}So7utFons. <br /> 3 GEOLOGIC SETTING <br /> 3.1 REGIONAL GEOLOGY <br /> The project site lies within the central portion of the Great Valley geomorphic province of <br /> California. The province is bordered to the north by the Cascade Range and Klamath Mountains, <br /> to the west by the structurally complex sedimentary and volcanic rock units of the Coast Ranges, <br /> to the east by the granitic and metamorphic basement rocks which form the gently sloping western <br /> foothills of the Sierra Nevada Mountains, and to the south by the east-west trending Transverse <br /> Ranges. About 645 km long and 80 km wide, the Great Valley is an asymmetrical, synclinal trough <br /> formed by tilting of the Sierran block during the late Tertiary and Quaternary periods with the <br /> western side dropping to form the valley and the eastern side uplifting to form the Sierra Nevada <br /> Mountains. Within the project area, erosion of the adjacent Sierra Nevada Mountains and Coast <br /> Ranges has in-filled this valley with a thick sequence of unconsolidated to semi-consolidated <br /> Quaternary (Pleistocene and Holocene) age alluvial, basin, and delta plain sediments deposited <br /> by the Sacramento and San Joaquin rivers and their tributaries. The thickness of the valley <br /> sediments varies from a thin veneer at the edges of the valley to thousands of meters in the <br /> western portion. The bedrock complex is likely composed of metamorphosed marine sediments <br /> similar to those found in the foothills of the western Sierra Nevada Mountains and the core of the <br /> Coast Ranges. <br /> 3.2 AREA AND SITE GEOLOGY <br /> The project site is situated within the central portion of the San Joaquin Valley and within the <br /> Stockton East 7'/2-minute quadrangle. This portion of the San Joaquin Valley consists of a very <br /> gently sloping alluvial fan flanked on the east by elevated alluvial fan and terrace surfaces <br /> dissected by modern streams. Farther to the east are the foothills of the Sierra Nevada Mountains. <br /> This portion of the San Joaquin Valley consists of Quaternary alluvial and fluvial sedimentary <br /> deposits that originated from the Sierra Nevada Mountains, which is comprised mostly of <br /> Mesozoic granitic bedrock and Mesozoic to Paleozoic metamorphic bedrock. <br /> 20210067.001A/ST020R111447 Page 6 of 37 May 11, 2020 <br /> ©2020 Kleinfelder www.kleinfelder.com <br />