Amount and timing of late Cenozoic uplift and tilt of the central Sierra Nevada, California: Evidence from the upper San Joaquin River basin

Abstract

The upper San Joaquin River is unique among the rivers that drain the western slope of the Sierra Nevada in that it flowed westward across the present crest of the range until as recently as about 3.2 mill ion years ago. Portions of the history of the river and of the topog raphic development of the central Sierra Nevada can be deciphered from tilted stratigraphic planes at the east margin of the Central Val ley and dated volcanic rocks within and east of the upper San Joa quin River's present drainage basin. Uplift of the central Sierra Nevada was probably underway by 25 m.y. ago, but at a relatively low rate, probably not exceeding about 0.03 mm/yr at the present drainage divide at Deadman Pass. Uplift proceeded at an increasing rate, and is an estimated 0.3 mm/yr at present; the rate may still be increasing. Total uplift at Deadman Pass in the past 50 m.