| 摘要: |
| 为了解东菲律宾海沉积物记录的地球磁场相对强度变化, 并为研究区的地层定年提供新的手段, 对东菲律宾海帕里西维拉海盆西侧 F090102 孔柱样沉积物进行了系统的古地磁和岩石磁学分析。根据功率谱分析, 选择非磁滞剩磁作为归一化的参数,得到约 2 Ma 以来的地球磁场相对强度变化曲线。该曲线与 SINT-2000 曲线可详细对比,呈比较典型的锯齿状特征, 布容期内的记录与 800 ka以来的SINT-800曲线相符。 布容/松山极性转换期呈单强度降低的特征, 在极性转换期和极性漂移期, 相对强度曲线表现为显著低值。
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| 关键词: 沉积物, 相对古地磁强度, 东菲律宾海 |
| DOI：10.11693/hyhz201004021021 |
| 分类号: |
| 基金项目:国家自然基金资助项目, 90411014 号和中国科学院知识创新工程重要方向资助项目, KZCX2-YW-211 号 |
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| A GEOMAGNETIC PALEOINTENSITY RECORD OVER THE LAST 2Ma FROM THE EAST PHILIPPINE SEA |
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MENG Qing-Yong1,2, LI An-Chun1, JIANG Fu-Qing1, XU Zhao-Kai1,2, ZHU You-Sheng3, LI De-Peng4
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1.Key Lab of Marine Geological & Environment, Institute of Oceanology, Chinese Academy of Sciences;2.Graduate School of the Chinese Academy of Sciences;3.China Oilfield Services Limited;4.National Marine Environment Monitoring Center
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| Abstract: |
| A detailed magnetic analysis has been conducted on the core F090102 from East Philippine Sea. Rock magnetic results demonstrate that the cores preserve a strong, stable remanent magnetization and meet the magnetic mineral criteria for reliable paleointensity analyses. Susceptibility (χ), anhysteretic remnant magnetization (ARM) and saturation isothermal remnant magnetization (SIRM) were used as the natural remanent magnetization normalizer. However, coherence analysis results indicates that only ARM is more suitable for paleointensity construction . The relative paleomagnetic intensity (RPI) record over the past about 2 Ma was obtained and was further compared to previously published stack records, SINT-800 and SINT-2000. Our new RPI record exhibits asymmetrical saw-tooth pattern of the geomagnetic field intensity and some major declines in paleointensity (DIP) at reversal boundaries as well as geomagnetic excursions. The Brunhes/Matuyama polarity transition was characterized by a single-DIP but not a double-DIP, it may be due to the low sedimentation accumulation rates. The record can be used to refine the chronological framework of the sediment in this region.
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| Key words: Sediment, Relative paleomagnetic intensity, Geomagnetic field, East Philippine Sea |
