Publications

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2013
Mitra, R, Tauxe L, McIntosh SK.  2013.  Two thousand years of archeointensity from West Africa. Earth and Planetary Science Letters. 364:123-133.   10.1016/j.epsl.2012.12.027   AbstractWebsite

This study presents 17 archeointensity estimates from Senegal and Mali, two neighboring countries in West Africa, for the period 1000 BCE to 1000 CE. The archeological artifacts used in this study were collected during the course of two separate projects, together spanning 22 years and across 8 separate excavations. A primary objective of this study was to get accurate dates, hence, only samples with independent age constraints from pottery style, detailed stratigraphy and C-14 dates were used. A total of 236 specimens from 63 samples were subjected to a double heating paleointensity experiment (IZZI method) from which 95 specimens were selected using a set of very strict selection criteria. The paleointensity results were corrected for differential cooling rate effects and remanence anisotropy. Additionally, we demonstrate the equivalence of using tensors derived from anhysteretic and thermal remanences for correcting remanent anisotropy of the specimens and use the form!

2011
Donadini, F, Elming SA, Tauxe L, Halenius U.  2011.  Paleointensity determination on a 1.786 Ga old gabbro from Hoting, Central Sweden. Earth and Planetary Science Letters. 309:234-248.   10.1016/j.epsl.2011.07.005   AbstractWebsite

Paleointensities from Precambrian rocks are rare and might be biased by remagnetization processes. Here we present new analyses of samples from a 1.786 Ga gabbro near Hoting, Central Sweden. Rock magnetic and mineralogical analyses indicate that one of the sites (site 5) may be pristine, whereas the others exhibit evidence of alteration. Characteristic remanent magnetization was determined using principal component analysis for each sample and was compared with results obtained in a previous study of Elming et al. (2009). Intensity measurements from site 5 show higher values compared to those of the other sites, suggesting that alteration processes may lead to underestimation of the field intensity. After cooling rate and anisotropy correction, the field moment at 1.786 Ga was estimated to be 25.6 +/- 33 ZAm(2) and 15.2 +/- 6.1 ZAm(2) from site 5 only and from all sites respectively. We consider the result from site 5 to be more accurate owing to the lack of evidence for alteration: our estimates agree well with the Proterozoic VDM values suggested by Biggin et al. (2009). (C) 2011 Elsevier B.V. All rights reserved.