Late Neogene and Quaternary Landscape Evolution of the Northern California Coast Ranges: Evidence for Mendocino Triple Junction Tectonics
Late Neogene and Quaternary landscape evolution of the northern California Coast Ranges: Evidence for Mendocino triple junction tectonics Jane Lock† Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA Harvey Kelsey‡ Department of Geology, Humboldt State University, Arcata, California 95521, USA Kevin Furlong§ Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA Adam Woolace# Department of Geology, Humboldt State University, Arcata, California 95521, USA ABSTRACT the double-humped pattern of uplift and our understanding of the lithospheric forces subsidence migrates, and the Coast Ranges that have built the orogen, and recognizing the A landscape records the surface response emerge. Smaller drainages develop and tectonic signal recorded by the landscape. We to tectonics at time scales intermedi- evolve by stream capture and fl ow reversal, describe how the surface responds to tectonics ate between short time-scale information and the two main divides migrate in concert in northern California, and we use the tectonic derived from seismic imaging and global with the triple junction. In contrast to the signal contained in the landscape to test and positioning systems and the long-term geo- systematic development of the small streams, develop our understanding of the geodynamics. logic record. We link late Neogene and the largest trunk streams can maintain grade A variety of mechanisms has been proposed Quaternary deposits and landforms in the through regions of high uplift, and coastal to explain the timing of uplift of the northern northern California Coast Ranges to the tec- river mouths remain stationary despite the California Coast Ranges. Dumitru (1989), using tonics of the Mendocino triple junction.
[Show full text]