THERMO-KINEMATIC MODELING OF DETACHMENT-DOMINATED EXTENSION, NORTHEASTERN DEATH VALLEY AREA, USA: IMPLICATIONS FOR MID-CRUSTAL THERMO-RHEOLOGICAL EVOLUTION (Tectonophysics PDF)
Thermo-kinematic modeling is an iterative method that integrates balanced kinematic reconstructions with forward numerical simulations of advective-conductive heat flow to predict cooling ages of thermochronometric samples.
The method constrains the geometric, kinematic and thermal evolution of a given tectonic transect. This methods has been applied to thrust systems often, but rarely to extensional settings.
I have generated the first regional-scale, thermo-kinematic models of detachment faulting in the Funeral Mountains, CA, USA.
Step-wise kinematic reconstruction of detachment faulting in the Death Valley region, showing two detachments, with tracking of thermo-chronometers (white dots) from one detachment footwall.
Stepwise reconstructions of faulting define a velocity-field through time that is used to simulate heat flow, detachment footwall cooling, and thermo-chronometric ages (see below).
We modeled the kinematic and thermal evolution of two detachment faults (BCD & OHD) in this western salient of the USA Cordilleran MCC belt.
1-Myr kinematic time-steps
were constrained by well-exposed surface relationships, syn-extensional stratal ages, paleo-topography constraints, and the thermo-chronometric data(white dots)
The Cordilleran thrust belt
is reconstructed and reveals new thrusts that were reactivated or cross-cut by the Miocene detachments
Mid-crustal velocity vectors
were generated from the upper-crustal reconstructions using various area-balancing schemes (thanks to Rich Ketcham, UT Austin)
A finite-element model
was created to simulate advective and conductive heat transport and track thermo-chronometer sample locations through temp-time space
Thermal histories
of tracked sample locations in detachment footwall are used to calculate model cooling ages, which are matched to existing data
Model cooling ages
are matched to existing cooling ages along the detachment footwall
Exhumed ductile shear zones
from the detachment footwall are used in tandem with the thermo-kinematic model solutions to locate the brittle-plastic transition through time.
A weak mid-crustal layer
existed prior to and during detachment faulting, but was subsequently “occluded” (Wernicke, 1992) or “annealed” (Pérez‐Gussinyé and Reston, 2001) due to thinning, exhumation, and cooling
Collaborators on this project
