Paleointensity Estimates of Neoprotorezoic North Shore Volcanic Samples

Friday, 19 December 2014
Hanna Fethee Asefaw and Lisa Tauxe, Scripps Institution of Oceanography, La Jolla, CA, United States
Tauxe and Kodama (2009) sampled 83 lava flows in the North Shore Volcanics (Keweenaw Peninsula, Michigan). Based on their demagnetization behavior (uni-vectorial and “square shouldered” demagnetization behavior), we selected 90 specimens from 28 sites and applied an alternating infield and zero-field paleointensity (IZZI) method (Tauxe and Staudigel 2004). Radiometric age constraints from U-Pb analysis of zircon has dated the sequence to the Neoprotorezoic, at approximately 1 Ga. The unblocking temperatures derived from the majority of the samples indicates that they are primarily composed of either hematite or magnetite; further analysis of their magnetic mineralogy is ongoing. Preliminary data are consistent with paleointensity estimates proposed by other investigations conducted in the surrounding region (Kulakov et al., 2013).

Kulakov, E., Smirnov, A., and Diehl, J. f., 2013, Stud. Geophys. Geod., v. 57, p. 565-584.

Tauxe, L., and Staudigel, H., 2004, Geochem. Geophys. Geosyst., v. 5, no. 2, p. Q02H06, doi:10.1029/2003GC000635.

Tauxe, L., and Kodama, K. P., 2009, Phys. Earth Planet. Int., v. 177, p. 31-45.