用开拓后的异常划分算子，根据实际资料从ΔＴ＿Ａ异常中分离出深部磁场，以裂谷地质观点指导进行定量计算、综合分析与研究，认为塔里木地区深部磁场是塔克拉玛干前震旦纪古裂谷的反映。该裂谷是古生代地台和部分中生代生油坳陷形成、发育的基础，也是控制塔里木盆地构造发展的基础，这一古裂谷的发现为塔里木盆地寻找大油气田指出了方向。 Using the developed anomaly division operator, the deep magnetic field is separated from the ΔT_A anomaly based on the actual data, and quantitatively guided by the rift geological point of view. Based on the comprehensive analysis and research, it is concluded that the deep magnetic field in the Tarim area is the anomaly of the ancient Sinian anomaly in the Taklimakan reflect. The rift is the basis of the formation and development of the Paleozoic platform and some of the Mesozoic oil depressions and also controls the structural development of the Tarim Basin. The discovery of this ancient rift pointed out the direction for the Tarim Basin to search for large oil and gas fields.