First-order (transform) and second-order ridge-axis discontinuities create a fundamental segmentation of the lithosphere along mid-ocean ridges, and in slow spreading crust they commonly are associated with exposure of subvolcanic rust and upper mantle. We analyzed available morphological, gravity, and rock sample data from the Atlantic Ocean to determine whether consistent structural patems oc...

Crustally-derived granites may be generated in a variety of tectonic settings, but whatever the ultimate causse of heating crustal thickening, crustal extension, enhanced heat flux from the mantle, or magmatic advection by mantle-derived melts crustal melting likely occurs in a dynamic environment. Under these conditions deviatoric stress acting on an anisotropic crustal source region will lead...

We use a strain-rate-dependent visco-plastic rheology in a finite element model to investigate the effects of crustal rheology and thermal structure on the development of normal faults in 2-D extending lithosphere. Strain-rate softening in the brittle regime is used to simulate the rate-dependence of frictional strength observed in laboratory studies. Results of numerical experiments show that ...

We present a quantitative assessment of the thermal and dynamic response of an amphibolitic lower crust to the intrusion of basaltic dike swarms in an arc setting. We consider the effect of variable intrusion geometry, depth of intrusion, and basalt flux on the production, persistence, and interaction of basaltic and crustal melt in a stochastic computational framework. Distinct melting and mix...

We investigate the thickness and seismic velocity structure of the Rukwa Rift crust by modeling seismograms from the 1994 Mw 5.9 Rukwa earthquake and teleseismic receiver functions recorded on a broadband seismic station at the southeastern end of the rift. Two methods have been used to model receiver functions, Hstacking and waveform inversion, yielding Moho depth estimates of 34 ± 2 km (Hstac...