Using U-Pb dating, estimated the timing of eclogite facies metamorphism, a process which require transport to mantle depth, to 1.904 Ga.
42.
The uppermost seismicity surface is in the crust of the down-going slab and attributed to the dehydration reactions within this oceanic crust resulting in the formation of eclogite.
43.
These events relate to normal faulting, associated with the bending of the slab, possibly related to a phase change below about 40 km from basalt / gabbro to eclogite.
44.
During the transition from basalt to eclogite, these hydrous materials break down, producing copious quantities of water, which at such great pressure and temperature exists as a supercritical fluid.
45.
The metamorphic transition from mafic granulite facies to the denser eclogite facies in the lower portion of the crust is the main mechanism responsible for creating negative buoyancy of the lower lithosphere.
46.
Adams'work showed that only two minerals, dunite and eclogite, could possible make up the discontinuity, and further exploration showed that dunite was a better fit than eclogite.
47.
Adams'work showed that only two minerals, dunite and eclogite, could possible make up the discontinuity, and further exploration showed that dunite was a better fit than eclogite.
48.
Melts derived from the eclogite or garnet-amphibole slab are strongly enriched in Sr ( no plagioclase in residue ) and depleted in HREE and Y ( abundant garnet in residue ).
49.
The landscape north and landward of Strawberry Spit is dominated by Ring Mountain, whose slopes are strewn with a multitude of boulders that include minerals such as mica, amphibolite and eclogite.
50.
They consisted originally of a sequence of deep-marine ( flysch ) sediments of Ordovician to Devonian age ( 480-360 million years old ) and early Paleozoic eclogite facies ).
