Anisotropy of Magnetic Susceptibility: Preliminary results from IODP Expedition 318 to Wilkes Land (Invited)
Abstract
IODP Expedition 318, January - March 2010 (Wellington - Hobart) drilled seven sites into the Antarctic margin recovering ~2500 m of Lower Eocene to Holocene sediments. Over 1000 discrete samples were taken from three drill sites spanning the Lower Eocene to late Pleistocene sections. These were measured for their directional properties as well as for the anisotropy of magnetic susceptibility (AMS). AMS data reflect changes in sedimentary fabric with depth. In simple sedimentary systems, dewatering and compaction of the sediment results in a monotonic increase in the degree of anisotropy of an essentially oblate fabric with a vertical axis of minimum susceptibility. The results from Expedition 318 sediments, however, showed a great deal of variation down hole including abrupt changes at inferred sedimentary hiatuses and oscillatory behavior echoing inferred changes paleoproductivity. Implications of our AMS results will be discussed. In particular we will address the use of AMS data for 1) identifying intervals suffering from even subtle drilling or sedimentary disturbance thereby aiding interpretation of the magnetostratigraphic results, 2) helping constrain the location and nature of sedimentary hiatuses, and 3) helping interpret sedimentary fabrics associated with major shifts in paleoproductivity.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMGP22A..01T
- Keywords:
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- 1518 GEOMAGNETISM AND PALEOMAGNETISM / Magnetic fabrics and anisotropy;
- 1594 GEOMAGNETISM AND PALEOMAGNETISM / Instruments and techniques