Publication Date:
2023-08-09
Description:
Heat flow data collected along the San Andreas plate boundary and in the subduction to translation transition at the Mendocino Triple Junction (MTJ) have played a defining role for the geodynamic processes associated with this fundamental change in plate boundary tectonics. In the 1980s, heat flow data led to the recognition that the frictional strength of the San Andreas fault is low (Lachenbruch and Sass, 1980), and there is a slab window in the wake of MTJ migration (Zandt and Furlong, 1982). More recently, heat flow data constrain crustal deformation along the San Andreas corridor (Mendocino Crustal Conveyor; Furlong and Govers, 1999; Guzofski and Furlong, 2002; and Furlong and Schwartz , 2004). These results explain the magnitude and spatial wavelength of the transition from low heat flow within the Cascadia subduction zone to elevated heat flow along the San Andreas plate boundary. Within this broad low-to-high heat flow pattern, there are locations of anomalous heat flow that remain enigmatic. In the region straddling the MTJ, observed heat flow values (75 mW/m2) are substantially higher than are seen both north and south of that region (~ 35 - 50 mW/m2). Combining these heat flow data with new crustal and upper-mantle seismic tomography and tectono-thermal modeling, we constrain the processes of MTJ-related crustal deformation and place the elevated seismicity in the vicinity of the MTJ into its seismo-tectonic context. The elevated heat flow is most likely a consequence of rapid exhumation following the passage of the southern edge of the subducting slab.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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