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| Rock-magnetic properties of Neogene sediments, northern flank of Tianshan Mountains | |
| 作者单位： | LI ChuanXin（Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China） ; GUO ZhaoJie（Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China;Lanzhou Institute of Geology,Chinese Academy of Sciences,Lanzhou 730000,China） ; MENG ZiFang（Lanzhou Institute of Geology,Chinese Academy of Sciences,Lanzhou 730000,China） ; LI HaiYan（State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China） ; ZHANG ZhiCheng（Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China） ; WU ChaoDong（Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China） ; |
| 基金项目： | 国家重点基础研究发展计划(973计划) |
| 摘 要： | Analyses of rock-magnetic properties of Neogene sediments of the Taxihe section, northern Tianshan Mountains, show that the section can be classified into three categories including lacustrine facies, fluvial facies and alluvial facies, which correspond to the lower, middle and upper of the Taxihe section respectively. The magnetic minerals of the lacustrine facies may be affected by the process of weath- ering, lithogenesis and biolithogenesis besides the source of the sediments. The natural remanence intensities are between 10-3 A/m and 10-2 A/m. The minerals are dominated by magnetite and the high coercive magnetic mineral may be goethite. The magnetic grains are the mixture of PSD SD or SD SP. The natural remanence intensities of the strata of fluvial facies are between 10-2 A/m and 10-1 A/m, about ten times that of the lacustrine facies. The magnetic minerals are mainly magnetite and hematite, and the magnetic grains are mainly PSD. The characteristic remanence (ChRM) carriers are magnetites. In the alluvial facies, the natural remanence intensities are mostly less than 1×10-2 A/m. The magnetic minerals of the series are dominated by magnetite and hematite, almost the same as the fluvial facies. But the difference is that most of the stepwise demagnetization can reveal two components and the ChRM carriers are hematites. The magnetic grains are PSD in terms of the hysteresis parameters. |
Rock-magnetic properties of Neogene sediments,northern flank of Tianshan Mountains |
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| Authors: | Li ChuanXin Guo ZhaoJie Meng ZiFang Li HaiYan Zhang ZhiCheng Wu ChaoDong |
| Institution: | 1. Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China 2. Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education (Peking University),Beijing 100871,China;Lanzhou Institute of Geology,Chinese Academy of Sciences,Lanzhou 730000,China 3. Lanzhou Institute of Geology,Chinese Academy of Sciences,Lanzhou 730000,China 4. State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China |
| Abstract: | Analyses of rock-magnetic properties of Neogene sediments of the Taxihe section, northern Tianshan Mountains, show that the section can be classified into three categories including lacustrine facies, fluvial facies and alluvial facies, which correspond to the lower, middle and upper of the Taxihe section respectively. The magnetic minerals of the lacustrine facies may be affected by the process of weathering, lithogenesis and biolithogenesis besides the source of the sediments. The natural remanence intensities are between 10−3 A/m and 10−2 A/m. The minerals are dominated by magnetite and the high coercive magnetic mineral may be goethite. The magnetic grains are the mixture of PSD+SD or SD+SP. The natural remanence intensities of the strata of fluvial facies are between 10−2 A/m and 10−1 A/m, about ten times that of the lacustrine facies. The magnetic minerals are mainly magnetite and hematite, and the magnetic grains are mainly PSD. The characteristic remanence (ChRM) carriers are magnetites. In the alluvial facies, the natural remanence intensities are mostly less than 1 × 10−2 A/m. The magnetic minerals of the series are dominated by magnetite and hematite, almost the same as the fluvial facies. But the difference is that most of the stepwise demagnetization can reveal two components and the ChRM carriers are hematites. The magnetic grains are PSD in terms of the hysteresis parameters. Supported by Major State Basic Research Program of China (Grant No. 2001 CB409804). |
| Keywords: | Northern flank of Tianshan Mountains Neogene magnetic carrier IRM temperature-dependent susceptibility Day plot |
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