2002-2003 Science Planning Summary

Geology & Geophysics

Dr. Scott Borg
Program Manager

GO-071-O

NSF/OPP 01-26340
01-26334
Station: RV/IB Nathaniel B Palmer
RPSC POC: Karl Newyear
Research Site(s): RV/IB NBP

Improved Cenozoic plate reconstructions of the circum-Antarctic region
Dr. Steve Cande
University of California, San Diego
Scripps institute of Oceanography
Dr. Stanley Jacobs
Lamont-Doherty Earth Observatory
Dr. Joann Stock
California Institute of Technology
Geological and Planetary Sciences
jstock@gps.caltech.edu
http://www.gps.caltech.edu/~jstock/Palmerres.html
http://www.gps.caltech.e

Deploying Team Members: Lauren K Annis . Manuel D Aragon-Arreola . John Behrendt . Steven C Cande . Robert W Clayton . Nathan J Downey . Peter H Molnar . Vincent Morton . Brian Savage . Kurt Schwehr . Joann M Stock
Research Objectives: Well-constrained Cenozoic plate reconstructions of the circum-antarctic region are critical for examining a number of problems of global geophysical importance. This group seeks to improve reconstructions involving the Antarctic and Pacific plates by surveying gravity, magnetics, and swath bathymetry on Palmer transit cruises of geological importance.

On transit cruise NBP 0207 they will take advantage of the planned track on the Pacific plate to survey across several major fracture zones, across part of the Manihiki Plateau and the Osbourne trough (to test aspects of the Mesozoic plate motion history of this region, when it may have been much farther south, adjacent to Antarctica), and along the Hikurangi trench (to study the rheology of the downgoing plate).

Also during the cruise the principal investigators will conduct a formal class in marine geophysics for 16 graduate and undergraduate students from a variety of institutions. In this way teaching activities can be integrated with the real field work of a research project.


Field Season Overview:
Field work for this project will take place over two cruises on the RV/IB Nathaniel B. Palmer, NBP 02-07 and NBP 02-09.

NBP 02-07 is a transit from California to New Zealand. The researchers will collect magnetometer, multibeam bathymetry, and gravity data. They will also do one to two days of multichannel seismic data collection, including launching sonobuoys. Expendable bathythermographs (XBTs) data will also be collected and used for processing the multibeam data. The RV/IB NBP's new magnetic gradiometer will also be tested during this cruise. During the cruise, the principal investigators will teach a formal class in marine geophysics to 16 graduate and undergraduate students.

The second cruise, NBP 02-09 will take place in the Ross Sea while McMurdo serves as home port for the RV/IB NBP. The researchers will have a party of 10 onboard. They will again collect magnetometer, multibeam bathymetry, sub-bottom profile, and gravity data. They will conduct one to two days of multichannel seismic data, including launching sonobuoys. Expendable bathythermographs (XBTs) will be launched every other day as for multibeam data processing. The cruise will also include continued testing of the new magnetic gradiometer.