格陵兰岛地区居里面深度

Curie depth in Greenland area

基于全球磁异常数据,利用质心法计算格陵兰岛地区的居里面深度,并结合最新的热流资料、地壳结构和大洋年龄进行分析,加深了对研究区热结构的认识。首先,总结了磁性体满足不同分布时,居里面深度计算的理论公式和校正因子的选择。在格陵兰岛地区应用分形分布,结果表明,研究区居里面深度h_(b)在40 km以内,平均值约为20 km,估算误差约为2.7 km。校正h_(b)得到地形到居里面的距离h_(m)和沉积层底界面到居里面的距离h_(c),并根据不同的地壳类型对地表实测热流数据校正得到Q_(s)。对比结果显示h_(m)与Q_(s)基本成负相关,计算结果合理。进一步分析表明,研究区居里面总体上浅于莫霍面,但在格陵兰岛北部部分区域居里面深于莫霍面,在大洋地区的h_(c)随洋壳年龄的增大而增大。

This paper estimates the Curie depth in Greenland area based on the global magnetic anomaly data by using the centroid method.For further analysis we introduce the latest heat flow data,crustal structure and ocean age,which helps to deepen the understanding of thermal structure in the studied area.When the magnetic body satisfies different distribution assumptions,the different theoretical formulas and correction factors for calculating the Curie depth are summarized.Among these distribution assumptions,we apply the fractal distribution assumption to the Greenland area.The result shows that the Curie depth(h_(b))in the studied area is within 40 km,with an average depth of about 20 km and an estimation error of about 2.7 km.Based on h_(b),we calculate the distance h_(m)from topography to Curie depth and the distance h_(c)from the top crystalline basement to Curie depth.Besides,we correct surface heat flow to ob-tain Q_(s)to different crustal types.We find that Q_(s)approximately inversely proportional to h_(m),which proves that the result is reasonable.Further analysis shows that h_(b)in the studied area is generally shallower than Moho depth,while in part of the northern Greenland,h_(b)is deeper than Moho.In the ocean,increases with the age of the ocean crust.