Curie Point Depth from Spectral Analysis of Magnetic Data in the Southeast Tibet

Abstract

The satellite magnetic anomalies are used to calculate the Curie point depth of the Southeast Tibet by spectral analysis method in the study. The relationship between the Curie point depth and the regional faults or heat flow will be discussed. The results show that the Curie point depth of the study area ranges from 15 km to 36 km and the average depth is 26.3 km. The Curie point depth is cluster-like on the north of the Ailaoshan-Red River Fault, while it is strip-like distribution on the north side. The Curie point depth in the Xiaojiang Fault zone, the Xiaojinhe Fault zone, the Dien Bien Phu Fault zone and the Gaoligong Fault zone are shallow. It could be related to their strong frictional heat induced by these faults. The Curie point depth in the middle Sukhothai Block is shallow, which it is not only related to the Phayao Fault, the Mae Chan Fault and the Nam Ma Fault, but also to the subduction of the Palaeo-Tethys into the Indochina Block. There is a negative but nonlinearly correlation between the heat flow and the Curie point depth in this study area. The areas of low heat flow value correspond to the areas of deep Curie point depth. However, both the high and low heat flow values can be found in the areas of shallow Curie point depth. The possible reason is thought to be related to the low thermal conductivity of the rock.