Paleointensity results from the late-Archaean Modipe Gabbro of Botswana
Article first published online: 19 JUL 2013
©2013. American Geophysical Union. All Rights Reserved.
Geochemistry, Geophysics, Geosystems
Volume 14, Issue 7, pages 2198–2205, July 2013
How to Cite
2013), Paleointensity results from the late-Archaean Modipe Gabbro of Botswana, Geochem. Geophys. Geosyst., 14, 2198--2205, doi:10.1002/ggge.20142., , , and (
- Issue published online: 3 SEP 2013
- Article first published online: 19 JUL 2013
- Accepted manuscript online: 15 APR 2013 06:01AM EST
- Manuscript Accepted: 9 APR 2013
- Manuscript Revised: 1 APR 2013
- Manuscript Received: 28 JAN 2013
- Modipe Gabbro;
 Rock-magnetic and Thellier-Thellier-Coe paleointensity results are reported for a new collection of samples from the 2.78 Ga Modipe Gabbro of Botswana. The magnetic properties are very favorable, leading to an unusually high success rate and a well-constrained result of 36–40 µT (95% confidence interval). We discuss the long-standing problem of allowing for the enormous differences between the natural and laboratory cooling rates, and apply a temperature-dependent correction derived from first-order reversal curve (FORC) data. Whereas pure single-domain (SD) corrections often lead to quite large decreases in paleointensity estimates (sometimes exceeding 50%), we find a modest increase of about 10%. The Earth's Magnetic Dipole moment in the late Archaean is thereby estimated to have been ∼6×1022 Am2.