以地質和地球物理而言，台灣是一個很有趣的地方。在短短的一千公里範圍內即有兩個隱沒系統及其過渡帶（台灣島）。台灣的造山運動與此二隱沒帶的消長息息相關。在磁力異常圖上，很明顯地可以看出，在台灣西南部地區有一個高磁力異常帶(稱為台灣西南高磁帶)。此高磁帶代表南中國海西北邊之被動大陸邊緣，是南中國海形成初期岩漿活動之遺跡。此高磁帶自海域向東北方延伸至台灣中心位置的埔里區而後終止，可能代表南海岩石圈亦延伸至台灣中部地區為了探討台灣西南的層構造、板塊構造和台灣造山運動，需利用地球物理數據。本論文針對台灣西南地區之強帶及其附近地區做橫切磁力異常剖面的逆推，希望了解此強磁帶及其附近地區之地下磁力基盤構造及其地質意義。而根據逆推之磁力基盤特性發現，西南高磁帶的南側應仍屬大陸板塊之特性，僅其上因覆蓋厚沉積層而下沉。

The Taiwan area is very interesting in geology and geophysics; in a short range of about 1000 km, there exist two subduction zones with opposite polarity and an island with vigorous orogeny. On the magnetic anomaly map of the Taiwan region, there exists a belt of high magnetic anomaly (HMA) in the southwestern Taiwan area, which trends about N60。E along the southeastern margin of the Eurasian continental plate. This HMA belt may represent the southeastern edge of the continental shelf off southeastern China and the relic trace of initial magma activity relating to the breakup of the South China Sea (SCS) from the Eurasian continental margin. The HMA belt extends northeastward to the area of the town of Puli in central Taiwan and ends there, indicating that the SCS lithosphere may also extend to this area. In this paper we conduct a modeling of a magnetic anomaly profile across the HMA belt, and then discuss the geological meaning of resulted magnetic basement, especially the role of HMA belt of the orogeny of Taiwan. We found that the southeastern side of the HMA belt should still be part of the continental part, only it deepens due to the overburden of thick sediment layer probably because of the Taiwan orgeny. Keywords: high magnetic anomaly belt in southwestern Taiwan, modeling of magnetic
basement, Taiwan orogeny.