Geomagnetic Modulation of the 36Cl Flux in the GRIP Ice Core, Greenland
S. Baumgartner,
J. Beer,
*
J. Masarik,
G. Wagner,
L. Meynadier,
H.-A. Synal
Geomagnetic field strength is expected to affect the production
rate of cosmogenic isotopes such as beryllium-10, carbon-14, or
chlorine-36. Chlorine-36 data from the Greenland Ice Core Project (GRIP) ice core agree well with a production rate calculation based on
a paleomagnetic reconstruction for the past 100,000 years over both
long- and short-term variations. A chlorine-36 peak at 38,000 years ago
previously found in the beryllium-10 record from the Vostok ice core
can be explained by a period of low geomagnetic field intensity.
S. Baumgartner, J. Beer, J. Masarik, G. Wagner,
Environmental Physics, Swiss Federal Institute of Science and
Technology, CH-8600 Dübendorf, Switzerland.
L. Meynadier, Laboratoire de Geochimie et Cosmochimie, CNRS 1758, Institut de Physique du Globe de Paris, 4 place Jussieu, F-75252 Paris
Cedex 5, France.
H.-A. Synal, Paul Scherrer Institut, c/o Eidgenössische
Technische Hochschule Hönggerberg, CH-8093 Zürich,
Switzerland.
*
To whom correspondence should be addressed.
