During the past few decades, most marine EM explorations were attempted to study electrical conductivity distributions in the upper mantle near mid-oceanic ridges
, hot-spot regions or subduction zones, where distinct lateral heterogeneities can be expected due to the vertical movement of mantle materials.
After that, MAR-ECO expanded the scientific cruises to the South Atlantic Mid-Oceanic Ridge
, from 0[degrees] to 34[degrees]S, in the Walvis Ridge Sector (WRS).
At mid-oceanic ridges
, rocks are hot and their density is low, making them buoyant or more able to float.
The trough associated with the mid-oceanic ridges
is deeply depressed, and on occasion extends into the lower mantle.
Each year, Congress has reinstated funding for this program, which includes, among other activities, expeditions with the submersible ALVIN to mid-oceanic ridges
Just as the scars and wrinkles on a person's skin can tell the story of a life, the faults and topography of the seafloor may reveal a history of the ocean crust as it is churned out at mid-oceanic ridges
For researchers who have used multibeam systems in their studies, "the data have been like allowing us to remove several layers of opaque glass and get closer to an accurate definition of the seafloor," says Jeff Fox at the University of Rhode Island at Narragansett, who uses academic Seabeam systems in his research on the magmatic and tectonic processes at mid-oceanic ridges
When scientists were outlining the scientific objectives of the Ocean Drilling Program (ODP) five years ago, they made drilling at mid-oceanic ridges
their number one priority.
Because these larger features have been well documented, Marsh's group focused on detecting smaller features such as the shape of the water above fracture zones that slice through mid-oceanic ridges
The seafloor has been likened to a giant tape recorder, because as it is churned out conveyor-belt-style at mid-oceanic ridges
, it becomes imprinted with the earth's changing magnetic field.
studied the rates at which the six major mid-oceanic ridges
churn out new lithosphere (oceanic crust overlying tectonic plates).