Somayajulu, B. L. K. ; Radhakrishnamurty, C. ; Walsh, T. J. (1978) Susceptibility as a tool for studying magnetic stratigraphy of marine sediments Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences, 87 (11). pp. 201-213. ISSN 0253-4126
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Official URL: http://www.ias.ac.in/j_archive/epsci/87/3/201-213/...
Related URL: http://dx.doi.org/10.1007/BF02861514
Abstract
Eighty six gravity cores collected from the Pacific Ocean by the Scripps Institution of Oceanography have been logged for magnetic susceptibility using a simple and rapid technique. These logs fall into three types: Type 1 showing several highs and lows, Type 2 with a single-broad-hump, and Type 3 showing nearly constant susceptibility with depth. Type 1 cores are found to be mainly from sediment-trap (trenches) areas which are close to the active volcanoes and the high peaks probably correspond to a slump or deposition of volcanic material; these events occurred between 0.1 and 2.8 million years ago. Type 2 cores are by far the most common, (56 out of 86) and show a maximum deposition of magnetic material (i.e. crest region of the hump) in the range of 0.2 and 1.7 million years. The susceptibility during this period was about a factor of two higher for several cores compared to their respective values during the last 0.1 million years. Oceanwide deposition of volcanic material and/or the atmospherically transported dust rich in magnetic material (cosmic and/or terrestrial) by our planet can account for such an increase. A third possibility may be the change (decrease) in accumulation rates of the sediments during this period. In type 3 cores the susceptibility is almost constant with depth and these are randomly distributed (excluding the sediment trap areas) analogous to the case of type 2 cores. A high deposition rate in these areas can alter type 2 into type 3. It appears that the maximum of type 2 hump can act as a stratigraphic marker since type 2 cores are the most common ones and are widely distributed over the entire Pacific.
Item Type: | Article |
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Source: | Copyright of this article belongs to Indian Academy of Sciences. |
Keywords: | Susceptibility; Magnetism; Stratigraphy; Pacific Sediments |
ID Code: | 49788 |
Deposited On: | 21 Jul 2011 10:17 |
Last Modified: | 18 May 2016 04:21 |
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