MAGNETOSTRATIGRAPHIC AND MAGNETIC PROPERTIES OF MARINE SEDIMENTS FROM THE EAST PHILIPPINE SEA
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摘要: 对东菲律宾海帕里西维拉海盆西侧F090102柱样进行了系统的古地磁和岩石磁学研究,测量了天然剩磁倾角、磁化率、饱和等温剩磁、非磁滞剩磁、X-T曲线等磁学参数,进行了磁性地层的划分对比,识别出松山反极性时内的贾拉米洛和奥都维正极性亚时。对磁学参数及其有关比值的研究发现,岩心磁性矿物以低矫顽力磁铁矿为主,可能含有一定的钛磁铁矿。磁性矿物主要是陆源碎屑成因,岩心底段受到海底火山作用的影响。根据磁学参数随深度的变化将岩心分为3段,各段反映了沉积环境和古气候的变化。Abstract: A detailed magnetic analysis has been done on core F090102 from the East Philippine Sea,and the following magnetic parameters were measured:susceptibility(X),anhysteretic remnant magnetization(ARM), saturation isothermal remnant magnetization(SIRM), IRM-300 mT (induced in a field of -300mT)and typical temperature dependence of magnetic susceptibility curves (X-T).Analyses of magnetic parameters demonstrated that magnetic minerals in the sequence are dominated by low-coercivity ferromagnetic minerals with subordinate high-coercivity antiferromagnetic minerals and are characterized by magnetite (probably including some titanomagnetites). The results show that the rock-magnetic parameters well correspond to the paleoclimatic variations and sedimentary environmental changes.And a magnetostratigraphic record was obtained.The Bruhnes-Matuyama reversal, the Jaramillo event as well as the Olduvai event during the Matuyama period were identified.
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Keywords:
- core sediments /
- magnetic properties /
- East Philippine Sea
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