Tectonics of ridge-transform intersections at the Kane fracture zone

摘要: The Kane Transform offsets spreading-center segments of the Mid-Atlantic Ridge by about 150 km at 24° N latitude. In terms its first-order morphological, geological, and geophysical characteristics it appears to be typical long-offset (>100 km), slow-slipping (2 cm yr-1) ridge-ridge transform faults. High-resolution geological observations were made from deep-towed ANGUS photographs manned submersible ALVIN ridge-transform intersections indicate similar relationships in these two regions. These data that over a distance 20 as spreading axes approach fracture zone, flanks each ridge axis behave very different ways. Along intersect active zone rift valley floor deepens surface expression volcanism becomes increasingly narrow eventually absent intersection where only sediment-covered ‘nodal basin’ exists. adjacent median walls have structural trends are oblique both much 4 relief. tectonically regions thin (<200 m), highly fractured, discontinuous carapace volcanic rocks overlying variably deformed metamorphosed assemblage gabbroic rocks. Overprinting reveal complex history crustal extension rapid vertical uplift. contrast, opposing axes, non-transform zones appear many respects those examined elsewhere along slow-spreading ridges. general, near-axial horst graben terrain floored relatively young volcanics passes laterally into with simple block-faulted character been found. strike toward youngest form linear constructional ridges transect entire width valley. continuous older-looking, slightly faulted floors valleys. document asymmetric nature seafloor near intersections. An important implication is crust lithosphere across portions will characteristics. Across plate edges formed corners against one another. younger section ridge-non-transform corner welded an older, initially corner.