"Recent discoveries from scientific ocean drilling have underlined that the process of creating new oceanic crust at seafloor spreading centers is complex," says Jamie Allan, IODP program director at the U.S. National Science Foundation (NSF), which co-funds the program.
"This work significantly adds to our ability to infer ocean crust structure and composition, including predicting how ocean crust has 'aged' in an area," says Allan, "thereby giving us new tools for understanding ocean crust creation from Earth's mantle."
Atlantis Massif is a classic example of an oceanic core complex.
Because it's relatively young--formed within the last million years--it's an ideal place, scientists say, to study how the interplay between faulting, magmatism and seawater circulation influences the evolution of an OCC within the crust.
"Vast ocean basins cover most of the Earth, yet their crust is formed in a narrow zone," says Blackman. "We're studying that source zone to understand how rifting and magmatism work together to form a new plate."
The JOIDES Resolution first visited Atlantis Massif about seven years ago; the science team on that expedition measured properties in gabbro.
But they focused on a shallower section, where pervasive seawater circulation had weathered the rock and changed its physical properties.
For the current expedition, the team did not drill new holes.
Rather, they lowered instruments into a deep existing hole drilled on a previous expedition, and made measurements from inside the hole.
The new measurements, at depths between 800 and 1,400 meters (about 2,600-4,600 feet) below the seafloor, include only a few narrow zones that had been altered by seawater circulation and/or by fault slip deformation.
The rest of the measurements focused on g
|Contact: Cheryl Dybas|
National Science Foundation