Research by Geographic Region
Marine Magnetism - Research Highlights by Geographic Region
Please note, most of this website is still under construction.
Kane Megamullion 2004 project utiizing ROV Jason-2 and
autonomous vehicle ABE was funded by NSF-ODP as a site survey of
potential drill targets for accessing lower crust and
upper mantle rocks exposed on the seafloor near 23°30'N. Click
below to find out more.
Sea surface magnetic data were collected over the west flank of
the Mid-Atlantic Ridge between 25° N and 27° N as part of the ONR (Office of
Naval Research) Acoustic Reverberation Study Research Project (ARSRP). Click
below to find out more.
High resolution magnetic field data have also been collected over
hydrothermal vents using submersible and deeptowed vehicles. The hot fluids
emanating from hot vents tends to chemically alter the magnetic minerals and
thus destroy any magnetic signal. The TAG hydrothermal site on the Mid-Atlantic
ridge is one place where we have documented the presence of a magnetic low over
the vent site.
Juan de Fuca Ridge, North East Pacific Ocean
Magnetic surveying of a steep scarp that exposes a cross-section
of ocean crust was conducted in 1995 at the Blanco Fracture Zone which marks the
southern boundary of the Juan de Fuca plate in the northeast Pacific. Magnetic
field measurements were made using the deep diving submersible ALVIN and also
the French submerisble NAUTILE. An important problem in marine magnetism
concerns the vertical structure of oceanic crust and what part of the crust is
responsible for creating magnetic anomalies that are measured at the sea
surface. Click below for more details on these results.
We are using magnetic field mapping to look at the change in
volcanic lava (also known as seismic layer 2A) thickness in comparison to the
seismic images of layer 2A. Magnetic field anomalies arise not only because of
thickness variations in the amount of extrusive lava but also due to the age of
the lavas. New lava is typically very magnetic and creates a strong magnetic
field signal when first formed. Click below for more details on these results.
Atlantis Bank South West Indian Ridge, Indian Ocean
Western Pacific Ocean
The western Pacific Ocean is the location of the world's oldest
ocean crust (~175 Million year old crust which places it in the Jurassic age
period). There has long been a debate over whether the Jurassic period was a
time of no magnetic reversals like the Cretaceous quiet zone or a time of very
rapid reversal of simply a time when the earths field was weaker. Few magnetic
measurements have been able to determine which of these scenarios is correct
with any accuracy. Sea surface magnetic measurements of this old crust are
easily contaminated by noise because of the equatorial location of the crust and
the seafloor is very deep (6.5 km). In 1991 I and my colleagues from the
University of Washington (Seattle) and Texas A&M University undertook a deeptow
survey of this oldest Pacific crust to try and determine if magnetic anomaly
reversals could be measured in such old crust. Click below for more details on
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