权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A detailed study of geomagnetic excursion by sediments

沉积物地磁偏移的详细研究

基本信息

批准号：
16540422
负责人：
ODA Hirokuni
金额：
$ 1.98万
依托单位：
National Institute of Advanced Industrial Science and Technology (AIST)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540422/
关键词：
Geomagnetic excursion Brunhes Normal Polarity Chron VGP path Relative paleointensity Iceland Basin excursion Sea level change Core-Mantle boundary Dipole magnetic field 地中海バイカル湖九州西方相対磁場強度氷期-間氷期サイクル IMAGES

项目摘要

Geomagnetic excursions during the Brunhes normal polarity Chron were reviewed and it was found that about 23 excursions exist and that 18 of them can be reliable with multiple records from other parts of the globe. Out of 23 excursions, 20 excursions can be correlated with the relative paleointensity minima of ODP Site 983, which may indicate that intensity of the Earth's magnetic field is low during geomagnetic excursions. The existence of large number of geomagnetic excursions during the Brunhes suggest that the Earth's magnetic field is rather unstable compared with the picture of the paleomagnetic field believed until now. A record of Iceland Basin excursion was obtained from Core Ver96-2, St. 7 in Lake Baikal, which gives Virtual Geomagnetic Pole (VGP) path on south Africa and Australia forming a counter clockwise circle around India. This is consistent with the other VGP paths from Lake Baikal and other records from North Atlantic and South China Sea, which suggests that the magnetic field during Iceland Basin excursion was dipoler as Laj et al. (2006) suggested. Two recent geomagnetic excursions were found from Core MD982195 at 14 and 6 ka, which can be correlated with the two excursions reported from Beijing, China at 14 and 5 ka (Zhu et al., 1998). These excursions can be generated by a differential rotation at the Core-Mantle boundary caused by a rapid rise in sea level due to melt water pulse 1A triggered by melt water discharge from Glacial Lake Aggasiz and by a sea level rise during Jomon transgression. The record of an excursion at 14 ka need careful investigation, because this part is affected by a disturbance seen in the anisotropy of magnetic susceptibility.

对Brunhes正极Chron期间的地磁偏移进行了审查，发现大约存在23个偏移，其中18个可以与来自全球其他地区的多个记录可靠。在 23 个偏移中，20 个偏移可以与 ODP 983 站点的相对古强度最小值相关，这可能表明地磁偏移期间地球磁场的强度较低。布伦赫斯期间大量地磁偏移的存在表明，与迄今为止所相信的古磁场图相比，地球磁场相当不稳定。冰岛盆地偏移的记录是从贝加尔湖的 Core Ver96-2, St. 7 获得的，该记录给出了南非和澳大利亚的虚拟地磁极 (VGP) 路径，形成了围绕印度的逆时针圆圈。这与贝加尔湖的其他 VGP 路径以及北大西洋和南中国海的其他记录一致，这表明冰岛盆地游览期间的磁场是偶极子，正如 Laj 等人所述。（2006）建议。最近在 MD982195 核心发现了 14 ka 和 6 ka 的两次地磁偏移，这可以与中国北京报告的 14 ka 和 5 ka 的两次地磁偏移相关（Zhu et al., 1998）。这些偏移可能是由核幔边界处的差异旋转引起的，该差异旋转是由于阿加西冰川湖融水排放引发的融水脉冲1A引起的海平面快速上升以及绳纹海侵期间海平面上升而引起的。 14 ka 偏移的记录需要仔细研究，因为这部分受到磁化率各向异性扰动的影响。