T391 Tectonics, Geohazards, and Morphodynamics from High-Resolution Topography and Imagery (Posters)

Wednesday, 25 October 2017
9:00 AM - 6:30 PM
Halls 4EF

QUATERNARY EXPRESSION OF NORTHERN GREAT VALLEY FAULTS AND FOLDS: ACCOMMODATING NORTH-SOUTH CONTRACTION BETWEEN THE SIERRAN MICROPLATE AND OREGON BLOCK

Paper number: T391-3
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The Northern California Shear Zone accommodates North American intraplate right-lateral transpressional shear driven by the relative motions of the northwest translating Sierran microplate and clockwise rotation of the Oregon block. Within this zone, between the latitudes of 40o and 42o, 1 – 4 mm/yr of north-south geodetic contraction is observed and for the most part remains geologically unaccounted for. The northeast trending Inks Creek fold belt, north of Red Bluff, CA, marks an abrupt change in structural orientation within the northern Great Valley and Sierra boundary, and consists of anticline-syncline pairs that appear optimally oriented to accommodate northwest directed crustal shortening. The folds plunge to the southwest where they are incised and deflect the course of the Sacramento River into a sinuous path. We will present new geomorphic mapping and analysis of fluvial terraces from airborne lidar data and field observations made along the Sacramento River within the fold belt. Evidence of uplift is observe from drain patterns and topographic profiling of Quaternary strath terrace surfaces, which show broad progressive arching through the fold belt. It is anticipated that radiocarbon, terrestrial cosmogenic nuclides, and OSL dating of the deformed terrace surfaces hold the potential to quantify the lateral and vertical propagation rates of fold growth, as well as, constrain rates of regional contractional deformation.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-306330

© Copyright 2017 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.