2016-2017 Science Planning Summaries
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2016-2017 USAP Field Season
Project Detail

Project Title

Finding the missing dipole signal in global paleointensity data: Revisiting the high southerly latitudes


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Summary

Event Number:
G-056-M

Program Manager:
Dr. Thomas Wilch

ASC POC/Implementer:
Jenny Cunningham / Bija Sass


Principal Investigator

Dr. Lisa Tauxe
ltauxe@ucsd.edu

Scripps Institution of Oceanography
Geoscience Research Division
La Jolla, California


Location

Supporting Stations: McMurdo Station
Research Locations: Ross and Black Islands / Mount Discovery / Royal Society Range / Taylor Valley


Description

The geomagnetic field is decreasing rapidly, leading some to propose that it will undergo collapse followed by a return to its usual strength but in the opposite direction, a phenomenon known as a "polarity reversal" which last happened about 800,000 years ago. Such a collapse would have a potentially devastating effect on the ability of the magnetic field to shield us from cosmic ray bombardment. The probability of such a drastic event happening depends on the average strength of the magnetic field. If the average is approximately equal to the present field, then the fact that the field is dropping rapidly would be more alarming than if the magnetic field is quite a bit higher than average, as implied by the current data for the ancient magnetic field from Antarctica. The argument over the average field strength stems from the difficulty of its estimation. To that end, researchers will re-sample ancient lava flows for which directional data are already available to explore the earth’s magnetic field strength and variation through time.


Field Season Overview

The science team will collect small paleomagnetic rock samples from 132 lava flows in the McMurdo area and analyze them to determine precise values of ancient geomagnetic field intensity. They will travel to most of their sites by helicopter, but will access some by foot and snowmobile. Time spent locating and sampling from each site will be roughly 30-45 minutes.


Deploying Team Members

  • Hanna Asefaw
  • Hubertus Staudigel (Co-PI)
  • Lisa Tauxe (PI)