Early and middle Matuyama geomagnetic excursions recorded in the Chinese loess-paleosol sediments
Early and middle Matuyama geomagnetic excursions recorded in the Chinese loess-paleosol sediments
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中国黄土-古土壤沉积物记录的早、中期松山地磁偏移
DOI：
10.1186/bf03352745
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发表时间：
2007-07
影响因子：
3
通讯作者：
Ding, Lin
中科院分区：
文献类型：
--
作者：
Mishima, Toshiaki;Yang, Tianshui;Yang, Zhenyu;Hyodo, Masayuki;Fu, Jianli;Ding, Lin
对陕西宝鸡剖面早、中期松山黄土-古土壤沉积进行了详细的古地磁和岩石磁学研究。我们的新磁静图将下Olduvai边界的位置从L27修正为S26。在L13、S22、L26、L27、S29和L32的上部和中部分别发现了7个短暂的地磁漂移，暂定名为E1、E2、E3、E4、E5、E6和E7。低场磁化率各向异性结果表明，所研究的黄土-古土壤沉积物保留了原始沉积组构。岩石磁学实验表明，漂移和极性转换段的沉积物与周围正、反极性段的沉积物具有相同的磁性特征。假设极界之间的累积速率不变，这7次漂移估计约为1.11 Ma(E1)、1.58 Ma(E2)、1.92 Ma(E3)、2.11 Ma(E4)、2.25 Ma(E5)、2.35 Ma(E6)和2.42 Ma(E7)Ma。Matuyama Chron中段的E_1和E_2可以分别与普纳鲁鲁和54阶段(吉尔萨)的漂移相关联。松山早期的E4、E5和E7可分别与留尼汪岛II、留尼汪岛I和隐时C2r.2r-1(X亚时)进行对比。Olduvai亚时下部的E3和Matuyama Chron早期的E6没有类似事件。目前，它们只能与在大阪湾岩心观察到的异常方向相关联(Biswaet al.，1999)。因此，有必要进一步调查，以支持它们在全球范围内的发生。这一结果与松山晚期的两次约0.89 Ma和0.92 Ma的漂移(Yang et al.，2004)表明，宝鸡剖面至少产生了9次松山漂移，与研究结果一起，表明在0.9-2.2 Ma(Channellet al.，2002)发生了8次漂移，从而提供了证据，表明短暂的地磁漂移也可能是松山时代地磁场的一个基本特征。
A detailed paleomagnetic and rock-magnetic investigation on the early and middle Matuyama loess-paleosol sediments has been carried out at the Baoji section, Shaanxi province, southern Chinese Loess Plateau. Our new magnetostatigraphy revises the position of the lower Olduvai boundary from L27 to S26. Seven shortlived geomagnetic excursions, tentatively named as E1, E2, E3, E4, E5, E6, and E7, have been recognized in the L13, S22, L26, L27, S29, and upper and middle parts of L32, respectively. Results of the anisotropy of low-field magnetic susceptibility (AMS) show that the studied loess-paleosol sediments retain the primary sedimentary fabric. Rock magnetic experiments reveal that the sediments from the excursional and polarity transitional intervals have the same magnetic characteristics as those from the surrounding normal and reversed polarity intervals. Assuming a constant accumulation rate between polarity boundaries, these seven excursions are estimated to be at about 1.11 Ma (E1), 1.58 Ma (E2), 1.92 Ma (E3), 2.11 Ma (E4), 2.25 Ma (E5), 2.35 Ma (E6), and 2.42 Ma (E7) Ma. The E1 and E2 in the middle Matuyama Chron can be correlated with the Punaruu and Stage 54 (Gilsa) excursions, respectively. The E4, E5, and E7 in the early Matuyama Chron can be correlated with the Réunion II, Réunion I, and cryptochron C2r.2r-1 (X-subchron), respectively. The E3 in the lower Olduvai subchron and E6 in the early Matuyama Chron have no comparable events. At present they can only be correlated with the anomalous directions observed in the Osaka Bay core (Biswaset al., 1999). Therefore, further investigations are necessary to support their global occurrences. The present result together with the two late Matuyama excursions dated at about 0.89 Ma and 0.92 Ma (Yanget al., 2004) show that the Baoji section yields at least nine Matuyama excursions which, along with the results of the study, suggests that eight excursions occur at 0.9–2.2 Ma (Channellet al., 2002), thereby providing evidence that the short-lived geomagnetic excursions may also be a basic characteristic of the geomagnetic field during the Matuyama Chron.
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影响因子：
64.8
作者：
L. Zhou;F. Oldfield;A. Wintle;S. Robinson;J. T. Wang
通讯作者：
L. Zhou;F. Oldfield;A. Wintle;S. Robinson;J. T. Wang
影响因子：
5.3
作者：
STEIGER, RH;JAGER, E
通讯作者：
JAGER, E
影响因子：
5.2
作者：
A. Baksi;K. Hoffman
通讯作者：
A. Baksi;K. Hoffman
影响因子：
5.3
作者：
C. S. Grommé;R. L. Hay
通讯作者：
C. S. Grommé;R. L. Hay
影响因子：
5.3
作者：
Zheng Hongbo;T. Rolph;J. Shaw;A. Zhisheng
通讯作者：
Zheng Hongbo;T. Rolph;J. Shaw;A. Zhisheng