Outcrop Geology of Plio-Pleistocene Strata of the Confidence Hills, Southern Death Valley, California

Abstract

The Confidence Hills, Southern Death Valley, California, are composed of Plio-Pleistocene lacustrine beds, evaporite beds, ashes, playa sediments, alluvial fan and fluvial deposits. The sediments have been divided into 5 mappable units. From oldest to youngest, they are: the Confidence Hills "formation· (informal) composed of three interfingering members, and overlying Units A and B which do not exhibit transitional contacts with either underlying units or with themselves. The Confidence Hills formation includes the lacustrine and playa fine sands, and silts and clays of fluvial sediments. The lower two members are characterized by the presence of anhydrite. This formation also contains at least 15 volcanic ashes useful for determining age and correlation. Unit B is a red-to-brown coarse fanglomerate that lies disconformably above the Confidence Hills formation. Unit A, a second fanglomerate deposit, overlies the other units in a prominent angular unconformity. The southernmost canyon was studied in greater detail, both lithostratigraphically and magnetostratigraphically (Beratan and Murray, and Pluhar et al., this volume). There are two primary structural features in the Confidence Hills: the Southern Death Valley fault zone and a large anticlinorium which makes up the Confidence Hills.