Paleoclimatic implications of magnetic susceptibility in Late Pliocene-Quaternary sediments from deep drilling core SG-1 in the western Qaidam Basin (NE Tibetan Plateau)
Paleoclimatic implications of magnetic susceptibility in Late Pliocene-Quaternary sediments from deep drilling core SG-1 in the western Qaidam Basin (NE Tibetan Plateau)
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柴达木盆地西部（青藏高原东北部）深钻岩芯 SG-1 晚上新世-第四纪沉积物磁化率的古气候意义
DOI：
10.1029/2011jb008949
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发表时间：
2012-06
影响因子：
3.9
通讯作者：
Zhang W.L., Erwin Appel, Fang X.M., Yan M.D., Song C.H., C
中科院分区：
文献类型：
--
作者：
Zhang W.L., Erwin Appel, Fang X.M., Yan M.D., Song C.H., C
湖泊沉积是研究古气候变化和侵蚀历史的重要档案。从青藏高原东北部柴达木盆地西部获得了长938.5 m的湖相沉积岩芯(SG-1)，其年龄为2.77~0.1 Ma，由暗灰色泥岩和浅灰色粉砂岩组成，上部夹有盐岩和细砂岩。分析了磁化率数据，结合岩石的详细磁性，揭示了铁(I)磁化率对过去气候变化和侵蚀的重要意义。质量比磁化率(χ)表现出明显的周期性和长期变化。χ值高的样品以磁铁矿和磁赤铁矿为主，具有拟单畴性质。相反，低χ值的样品含有从单域到多域的磁铁矿，此外，还含有大量赤铁矿。χ变化的驱动机制可以用三种不同的模式来解释：(1)不同的源区在较宽的腹地(干冷气候)发生风和冷碎屑侵蚀的交替，从较窄的区域(较湿的气候)发生地表径流侵蚀；(2)和3)低温氧化，发生在风化过程中的湖泊沉积物(较干的气候)或集水区(较潮湿的气候)。χ的变化趋势与沉积速率的变化相吻合，并与深海δ18O在冰期-间冰期时间尺度上的记录大致同步。因此，柴达木盆地西部沉积物中磁性矿物的浓度可能受构造影响和古环境变化的共同控制，但最好的解释是亚洲干燥和全球降温导致的干冷和湿润时期的交替和趋势。
Lake sediments are important archives of paleoclimate change and erosion history. A 938.5 m long core (SG‐1) of lacustrine sediments, dated at 2.77 Ma to 0.1 Ma, was obtained from the western Qaidam Basin in the northeastern Tibetan Plateau, consisting of dark grayish mudstone and grayish siltstone, intercalated with salts and fine sandstones in the upper part. Magnetic susceptibility data, combined with detailed rock magnetic properties, were analyzed for revealing the significance of ferro(i)magnetic concentration for past changes of climate and erosion. Mass‐specific susceptibility (χ) shows a striking cyclic and long‐term variation. Samples with high χ values are dominated by magnetite and maghemite with pseudo‐single‐domain properties. In contrast, samples with low χ values contain maghemite from single‐domain to multidomain and, additionally, a significant fraction of hematite. The driving mechanism of χ variation can be explained by three alternative models: (1) different source regions with alternations of wind and cryoclastic erosion in a wider hinterland (dry‐cold climate) and surface runoff erosion from a narrower area (more humid climate) and (2 and 3) low‐temperature oxidation, occurring either in the lake sediments (dry climate) or in the catchment area during weathering (more humid climate). Trends of χ match with changes in sedimention rates and are roughly synchronous with the deep‐sea δ18O record on a glacial‐interglacial timescale. Therefore, the concentration of magnetic minerals in the western Qaidam Basin sediments is likely controlled by both tectonic influence and paleoenvironmental changes but can be best interpreted by alternations and trends of dry‐cold and more humid periods due to Asian drying and global cooling.
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影响因子：
12.1
作者：
Y. Yechieli;W. Wood
通讯作者：
Y. Yechieli;W. Wood
DOI：
10.1029/2004eo200009
发表时间：
2004-05
期刊：
Eos, Transactions American Geophysical Union
影响因子：
--
作者：
J. Geissman
通讯作者：
J. Geissman
影响因子：
2.8
作者：
Hrouda, F;Jelinek, V;Zapletal, K
通讯作者：
Zapletal, K
DOI：
10.1016/s0031-0182(98)00048-0
发表时间：
1998-07
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
--
作者：
Li Ze-chun;Wang Yongjin;Chengzhi Ye;Liang Xuesong;Li Qingchen
通讯作者：
Li Ze-chun;Wang Yongjin;Chengzhi Ye;Liang Xuesong;Li Qingchen
影响因子：
2.8
作者：
N. Nowaczyk;P. Minyuk;M. Melles;J. Brigham‐Grette;O. Glushkova;M. Nolan;A. Lozhkin;T. Stetsenko-
通讯作者：
N. Nowaczyk;P. Minyuk;M. Melles;J. Brigham‐Grette;O. Glushkova;M. Nolan;A. Lozhkin;T. Stetsenko-