北越南位於與喜馬拉雅構造結有關的變形帶之東南部，被認為是研究東南亞地體構造演化的重要區域之一。直到現今，對於此區域之活動型態仍有待研究，特別是如Fansipan山脈與Tule山脈的高山區域。因此，本論文以探討這些山脈地區之構造變形與潛在活動性為目標，並了解其與造山作用的關聯性。 本篇論文的第一章聚焦於地形特徵與應力場資料分析，用以約制中南半島（包含越南、寮國及柬埔寨）地勢最高的Fansipan山脈變形型態與潛在活動性。地形分析的結果意味著Fansipan山脈的岩石抬升模式在空間分佈上於南部的西南邊抬升速率相對其他地區高。特別的是，高抬升速率區域伴隨Phong Tho-Nam Pia正斷層，這樣空間上的緊密關係代表著正斷層活動在此山脈構造抬升中扮演一個重要的角色。應力場調查資料顯示Fansipan山脈與其周圍地區曾歷經走向滑移與正斷層之非均質混合作用，且無明顯時間關係。在相同東北─西南向的張應力σ3下，走向滑移與正斷層活動的混合被解釋為σ1/σ2的應力場轉變結果。應力交互作用環境可能主導了近期越南北部的地體構造變形。 本論文的第二章利用野外觀察、數值高程模型資料與地形分析去約制近期貢獻於Fansipan山脈與Tule山脈抬升的活躍運動。從數值高程模型、野外調查與地形分析的結果顯示，Fansipan山脈與Tule山脈的近期變形皆有經歷張力環境下走向滑移及正斷層活躍活動的特徵。此張力環境伴隨侵蝕作用可以解釋為促使山脈抬升的一個主要因素。地體構造與侵蝕過程的交互作用導致下部地殼的物質因地殼均衡向上回彈，以致於在受季風影響的區域中，歷經長時期持續的風化侵蝕作用後仍能維持山脈高度。 ;Located in the southeastern-most of the deformation zones related to Himalayan syntaxis, northern Vietnam is considered as one of the most important regions for studying the tectonic evolution of SE Asia. Until now, there is still a lack of knowledge regarding active movements in this region, particularly in high mountainous areas such as the Fansipan and Tule mountain ranges. Therefore, the aim of this thesis is to obtain tectonic deformations and potential active movements of these mountain ranges and to further understand their relationship to the mountain building process. The first chapter of this thesis focuses on analyzing topographic features and stress field data to constrain deformation patterns and potential active movements of the Fansipan mountain range, the highest topography in the Indochina area (including Vietnam, Laos, and Cambodia). The results from topographic analyses suggest a spatial variation in rock uplift patterns of the Fansipan mountain range with the inferred higher uplift rate on the SW side of the south part as compared to the other sides. Specifically, the inferred high uplift rate on the SW side of the south part is spatially accompanied by the Phong Tho-Nam Pia normal fault. This spatially close association suggests that the normal faulting activity likely plays an important role in tectonic uplift of this mountain range. The investigation of stress field data indicates that the Fansipan mountain range and its surrounding areas have undergone an inhomogeneous mixture of strike-slip and normal faulting with no obvious timing relationship. The mixture of strike-slip and normal motions is interpreted as a result of stress permutation σ1/σ2 under the same extensional stress regime of NE-SW σ3. This alternating stress environment may dominate recent tectonic deformations of northern Vietnam. The second chapter of this thesis utilized observations from the field and digital elevation model (DEM) data and geomorphic analyses to constrain active movements that have likely contributed to recent uplift of the Fansipan and Tule mountain ranges. The results from DEM and field observations and geomorphic analyses suggest that the recent deformations of the Fansipan and Tule mountain ranges are characterized by active movements of both strike-slip and normal faults that experience extensional tectonics. The extensional tectonics together with erosional process are interpreted as a major factor driving the uplift of the mountain ranges. The interaction between tectonics and the erosional process leads materials in the lower crust to move upward by isostatic rebound to maintain high elevations of mountain ranges over long periods despite the continuous weathering and erosion present in monsoon-affected areas.
