Heat transfer from the oceanic crust to the ocean is accelerated by hydrothermal circulation. In 2003, Andy Fisher and colleagues measured heat flow over some seamounts off the flank of the Juan de Fuca ridge. Their measurement transects showed heat flow patterns with highs and lows where seamounts poke up through the 500 m-thick layer of sediment.


The spatial distribution of hydrothermal vents along the Mid-Atlantic Ridge may be related to spreading rate. In this map, German et al. (1998) show temperature and methane anomalies in the water column associated with vents.


Oceanic core complexes form when extension is faster than magmatic productivity. Blackman et al. (2002) studied the core complex at the intersection of the Mid-Atlantic Ridge and the Atlantis Fracture Zone. The core complex forms a mountain on the seafloor, capped by a striated footwall surface. A geologic map of the core complex shows deeply exhumed ultramafic rocks cut by the fault surface, flanked by volcanics and talus. For comparison, check out the Death Valley Detachment, a similar core complex currently active in Southern California.


McGuire and colleagues (2012) showed that the earthquake cycle on transform faults is different, and much shorter, than that on continental faults. The Gofar Transform fault is strongly expressed in bathymetry, and epicenters for a 4 month period show which strand is active. Note rotated magnetic stripes between the two fault strands of the transform.


Jessica Warren at Stanford studies the rheology of peridotite using rocks dredged from fracture zones as well as collected from ophiolites. Check out her page for some great field photos and photomicrographs.