摘要
使用改进的Thellier-Thellier双加热方法,对来自新疆昌吉、喀什以及塔什库尔干等地的考古陶片样品进行系统的古地球磁场强度实验和岩石磁学实验。结果显示,部分样品携带稳定的原生剩磁,从中获得约1000BC至约1200AD之间的地球磁场强度数据。经过各项检验和校正后,得到约5×10^(22)~11×10^(22) Am^(2)的虚轴向偶极矩(VADM)数据,与同时期中国其他地区的VADM数据大致处于同一区间,但是变化幅度较大,与全球地磁场模型SHAWQ2k存在不一致之处。将所得数据与约800AD的中东地区古地球磁场强度峰值以及约200AD的东亚地区古地球磁场强度峰值进行比较,拟合结果表明,中国新疆地区可能在约540AD时存在一个古地球磁场强度高峰,达峰时间介于东亚地区与中东地区之间。这一结果与非偶极子场的西向漂移特征相符,进一步说明该古地球磁场强度高峰可能与地球外核结构的演化相关。
A geomagnetic field paleointensity study using an improved double heating Thellier-Thellier type method(IZZI method)and a rock magnetic study were conducted on archaeological pottery samples from Changji,Kashgar,Tashkurgan,and other areas in Xinjiang Uyger Autonomous Region(China).The results show that some samples carried stable primary remanent magnetization,from which geomagnetic field paleointensity data between≈1000BC and≈1200AD were acquired.Series criteria were applied to select reliable result and corrections were performed to the paleointensity data.Virtual axial dipole moments(VADM)of≈5×10^(22)-11×10^(22) Am^(2) were obtained.The paleo-intensities obtained are roughly in the same range as the data published in other regions of China in the same period,but the amplitude of variation is significant,which is inconsistent with the global geomagnetic field model SHAWQ2k.The new data were compared with the geomagnetic field intensity peak in the Middle East region at≈800AD and the geomagnetic field intensity peak in East Asia region at≈200AD.The fitting results indicate a geomagnetic field intensity peak might exist in Xinjiang region at≈540AD,with the time of reaching the peak between East Asia and the Middle East region.This result is consistent with the westward drift characteristics of non-dipole fields,further indicating that this geomagnetic field paleointensity peak may be related to the dynamics of the Earth’s outer core.
作者
李能韬
周庭红
黄宝春
LI Nengtao;ZHOU Tinghong;HUANG Baochun(The Key Laboratory of Orogenic Belt and Crustal Evolution(MOE),School of Earth and Space Sciences,Peking University,Beijing 100871;Department of Earth and Environmental Sciences,University of Rochester,Rochester,NY 14627)
出处
《北京大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第3期503-512,共10页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
北京大学构造磁学实验室自主研究课题资助。
关键词
古地球磁场强度
岩石磁学
新疆地区
考古陶片
geomagnetic field paleointensity
rock magnetic
Xinjiang Uygur Autonomous Region
archaeological pottery
