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Detailed Reference Information |
Garcia, A.S., Thomas, D.N., Liss, D. and Shaw, J. (2006). Low geomagnetic field intensity during the Kiaman superchron: Thellier and microwave results from the Great Whin Sill intrusive complex, northern United Kingdom. Geophysical Research Letters 33: doi: 10.1029/2006GL026729. issn: 0094-8276. |
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Coe-Modified Thellier (CMT) and Microwave (MW) paleointensity experiments were conducted on samples from the multi-phase late Carboniferous (ca. 301 Ma) to early Permian (ca. 270 Ma) Great Whin Sill complex. Statistically comparable results were obtained with both techniques from high quality data. Forty three samples (25 with CMT and 18 with MW) yielded mean paleointensity values of 12.0 ¿ 5.8 ¿T and 16.5 ¿ 8.2 ¿T for the early and late intrusive phases respectively, corresponding to VDMs of (1.6 ¿ 0.8) ¿ 1022 and (2.1 ¿ 1.1) ¿ 1022 Am2. When combined with previous data, the results suggest a generally low dipole moment during the KRS, reducing from ~75% of the present value at 301 Ma to 20--27% of the present value later in the superchron. These data imply either a decoupling between processes controlling reversal rate and field strength, or a more complex, intriguing time-lag relationship. More absolute palaeointensity results are needed to further evaluate these alternatives. |
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Keywords
Geomagnetism and Paleomagnetism, Paleointensity, Geomagnetism and Paleomagnetism, Paleomagnetism applied to geologic processes, Geomagnetism and Paleomagnetism, Rock and mineral magnetism, Geomagnetism and Paleomagnetism, Time variations, secular and longer |
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American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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