Epeirogenic transients related to mantle lithosphere removal in the southern Sierra Nevada region, California: Part II. Implications of rock uplift and basin subsidence relations

Abstract

We investigate the putative Pliocene-Quaternary removal of mantle lithosphere from beneath the southern Sierra Nevada region using a synthesis of subsidence data from the Great Valley, and geomorphic relations across the Sierra Nevada. These fi ndings are used to test the results and predictions of thermomechanical modeling of the lithosphere removal process that is specifi c to the Sierra Nevada, as presented in an accompanying paper referenced here as Part I. Our most successful thermomechanical model and the observational data that it explains are further bundled into an integrated physiographic evolution-geodynamic model for the threedimensional epeirogenic deformation fi eld that has affected mainly the southern Sierra Nevada-San Joaquin Basin region as a result of underlying mantle lithosphere removal.The coupled Sierra Nevada mountain range and Great Valley basin are recognized as a relatively rigid block (Sierra Nevada microplate) moving within the San AndreasWalker Lane dextral plate juncture system. Our analysis recognizes that the Sierra Nevada possessed kilometer-scale local and regional paleotopographic relief, and that the Great Valley forearc basin possessed compara ble structural relief on its principal stratigraphic horizons, both dating back to the end of Cretaceous time. Such ancient paleorelief must be accounted for in considering late Cenozoic components of uplift and subsidence across the microplate. We further recognize that Cenozoic rock and surface uplift must be considered from the perspectives of both local epeirogeny driven by mantle lithosphere removal, and regional far-fi eld-forced epeirogeny driven by plate tectonics and regional upper-mantle buoyancy structure. Stratigraphic relations of Upper Cretaceous and lower Cenozoic marine strata lying on northern and southern Sierra Nevada basement provide evidence for near kilometerscale rock uplift in the Cenozoic. Such upliftis likely to have possessed positive, and then superposed negative (subsidence) stages of relief generation, rendering net regional rock and surface uplift. Accounting for ancient paleorelief and far-field-driven regional uplift leaves a residual pattern whereby ~1200 m of southeastern Sierra crest rock and similar surface uplift, and ~700 m of spatially and temporally linked tectonic subsidence in the southern Great Valley were required in the late Cenozoic by mantle lithosphere removal. These values are close to the predictions of our modeling, but application of the model results to the observed geology is complicated by spatial and temporal variations in the regional tectonics that probably instigated mantle lithosphere removal, as well as spatial and temporal variations in the observed uplift and subsidence patterns. Considerable focus is given to these spatial-temporal variation patterns, which are interpreted to refl ect a complex three-dimensional pattern resulting from the progressive removal of mantle lithosphere from beneath the region, as well as its epeirogenic expressions. The most signifi cant factor ...

Salinia revisited: a crystalline nappe sequence lying above the Nacimiento fault and dispersed along the San Andreas fault system, central California

“…south of Coalinga to north of Bakersfield) (Figures 1, 2B, and 9A). Alternatively, the abrupt termination of the structure contour lines in Wentworth et al (1995Wentworth et al ( , revised 2012 figure 1) and in Saleeby et al (2013, figure 1), along the western side and near the southern end of the San Joaquin Valley, can be interpreted as the loss of resolution of basement. That alternative is not favoured here owing to the remarkable uniformity of the abrupt termination of the structure contour lines (Wentworth et al 1995(Wentworth et al , revised 2012Saleeby et al 2013).…”

“…Alternatively, the abrupt termination of the structure contour lines in Wentworth et al (1995Wentworth et al ( , revised 2012 figure 1) and in Saleeby et al (2013, figure 1), along the western side and near the southern end of the San Joaquin Valley, can be interpreted as the loss of resolution of basement. That alternative is not favoured here owing to the remarkable uniformity of the abrupt termination of the structure contour lines (Wentworth et al 1995(Wentworth et al , revised 2012Saleeby et al 2013). In addition, when the NSD is palinspastically restored along and within the SAF system (Table 1), the inferred discontinuity truncates the structure contour lines at the southern end of the San Joaquin Valley (Wentworth et al 1995(Wentworth et al , revised 2012 figure 1, from near seismic line SJ6 to the southeast) (discontinuity, Figures 1 and 9A and 9B).…”

“…For the locations of Figures 9A and 9B, see Figure 1. (1997,2003), and Saleeby et al (1987Saleeby et al ( , 2007Saleeby et al ( , 2008Saleeby et al ( , 2009aSaleeby et al ( , 2009bSaleeby et al ( , 2010Saleeby et al ( , 2013 are paramount to understanding the region.…”

“…In addition, the following references were considered in the development of this figure: Crowell (1952), Dibblee and Chesterman (1953), Burchfiel and Davis (1981), Silver (1982Silver ( , 1983Silver ( , 1986, Ross (1984Ross ( , 1988Ross ( , 1989. Saleeby et al (1987Saleeby et al ( , 2009aSaleeby et al ( , 2009bSaleeby et al ( , 2013, Busby-Spera and Saleeby (1990), Saleeby (1993, 1994), Saleeby (1997Saleeby ( , 2003, Barbeau et al (2005), Clark et al (2005), Ducea et al (2009. For the locations of Figures 9A and 9B, see Figure 1.…”

“…The inferred and dotted black contact inFigure 9Bis in part based on the eastern outcrop limit of Franciscan mélange depicted bySaleeby et al (2013), figure 1).…”