Geology of the southernmost part of Santa Clara County, California: A digital database

The area of study for this report is the southern portion of Santa
Clara County that lies within the Monterey 30 by 60 minute
quadrangle, consisting of parts of the Watsonville East, Chittenden,
San Felipe, Three Sisters, and Mariposa Peak 7.5 minute
quadrangles. The study involved combining compilation of previous
published and unpublished work in the area with new mapping
completed in the first half of 1997. The study area makes up a
transect of the central California Coast Ranges, starting just east
of the San Andreas fault and continuing east across the Santa Cruz
Mountains, the Santa Clara Valley, and into the heart of the Diablo
Range. The area includes five fault-bounded structural blocks, each
containing a distinct stratigraphic assemblage, and the Santa Clara
Valley which contains a large Quaternary alluvial complex overlying
and obscuring bedrock relationships. Several active faults,
including the Sargent, Castro, and Calaveras faults, as well as
others with an unknown amount of recent activity, including the
Carnadero, San Jose, and Madrone Springs faults, cut the study area
with a general north-northwest trend.

本报告的研究区域为圣克拉拉县南部，地处蒙特雷30×60分幅地质图幅（quadrangle）范围内，涵盖沃森维尔东（Watsonville East）、奇滕登（Chittenden）、圣费利佩（San Felipe）、三姐妹（Three Sisters）以及马里波萨峰（Mariposa Peak）等5幅7.5分幅地质图幅的部分区域。本研究整合了该区域此前已发表及未发表的相关资料，并结合了1997年上半年完成的全新地质填图工作。研究区域横跨加利福尼亚中部海岸山脉，起点位于圣安德烈亚斯断层（San Andreas Fault）东侧，向东依次穿越圣克鲁斯山脉、圣克拉拉谷，最终深入迪亚布洛山脉腹地。该区域包含5个受断层约束的构造地块，每个地块均拥有独特的地层组合；此外还涵盖圣克拉拉谷，谷内发育有大规模第四纪（Quaternary）冲积复合体，覆盖并掩盖了基岩接触关系。多条活动断层（包括萨金特断层、卡斯特罗断层及卡拉韦拉斯断层）以及若干近期活动规模不明的断层（如卡纳达德罗断层、圣何塞断层与马德龙斯普林斯断层）以大致北北西的走向横穿研究区域。