Sea-floor lava fields on the East Pacific Rise
In: Geology. Geological Society of America: Boulder. ISSN 0091-7613; e-ISSN 1943-2682, more
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| Keywords |
Earth sciences > Geology > Geomorphology
ISE, East Pacific Rise
Measurement > Depth measurement > Echosounding
Morphology
Morphology
Morphology
Ocean floor
Rocks > Igneous rocks > Volcanic rocks > Lava
Topographic features > Submarine features > Seamounts
Topography
Volcanoes
East Pacific Rise [Marine Regions]
Marine/Coastal |
| Abstract |
A Se-Beam and SeaMARC I survey of a seamount group located several kilometers west of the axis of the East Pacific Rise (EPR) at lat 9 degree 53'N defines the existence of a large submarine lava field at the base of one of the volcanoes (MIB). The field must be relatively young with respect to the surrounding terrain because lavas lap up against the base of MIB seamount, obscurring older erosional terrain, and extend out over the faulted, sedimented terrain of the flank of the EPR. Volcanic cones within the lava field are aligned with the strike of fault scarps that are buried by the lavas. MIB seamount is characterized by a large, well-developed caldera, and it is suggested that the lava field was created during a recent volcanic episode when magmas migrated laterally away from the seamount's reservoir along preexisting faults parallel to the ridge axis. Draining of shallow-level magma chambers under seamounts by pressure-controlled basal-flank eruptions that form lava fields is an important mechanism for the development of seamount morphology. |
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