Abstract Structural mapping and analyses reveal deformation in the rocks of the Lesser Himalayan Miri and Gondwana, and Lower Siwalik Dafla successions across the Miri Thrust (MT) and the Main Boundary Thrust (MBT) in the Garu-Gensi area (Arunachal Himalaya, India). The-north-dipping Gondwana sequence is sandwiched between the Miri Group of rocks in the north and the Lower Siwalik Dafla sandstones in the south. The Gondwana rocks folded four times (D1-D4). Detail outcrop mapping and structural analyses substantiated by satellite images elucidate that the Miri, the Gondwana and the Lower Siwalik rock sequences in the area are traversed by two sets of NW and NE trending cross-fault zones with~70–100 m thickness mappable for ~70 km. The cross-faults trend NW around the locality Daring, while in the western part around Gensi, they trend NE. The westernmost fault slipped dextrally and the easternmost one at Daring sinistrally. These transverse faults offset the MBT: 0.52–0.59 km for the western- and 0.58–1.41 km for the eastern faults. The deformation in the Gondwana sequence may be constrained as syn-Himalayan (i.e., India-Asia collisional event). This was followed by a compression from E/ESE due to the post-Eocene Indo-Burmese collision. The culminating phase of combined India-Asia and Indo-Burmese compression is manifested in field with a strong NE-directed compression with dextral Reidal shear developing in the transverse conjugate fault zones in the area with maximum displacement towards SE. Cluster of the earthquake data indicates record of the events (M ≥ 6) within 30–80 km depth-both N and S of the MBT in the study area. Further, the southerly continuation of the transverse faults below the alluvium can provide vital clue in studying the potential hydrocarbon trap in the northern fringe of the Brahmaputra river.

中文翻译：

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喜马拉雅东部造山带-横断构造：Garu-Gensi 地区（印度阿鲁纳恰尔邦）沿主边界逆冲断层的右旋 Reidal 剪切，对油气地球科学的影响

摘要 结构测绘和分析揭示了小喜马拉雅美里和冈瓦纳、以及下 Siwalik Dafla 层序中的岩石变形，横跨美里逆冲断层 (MT) 和加鲁-根西地区（印度阿鲁纳恰尔喜马拉雅山）的主边界逆冲断层 (MBT) . 北倾冈瓦纳层序夹在北部的 Miri 岩石群和南部的下 Siwalik Dafla 砂岩之间。冈瓦纳岩石折叠四次（D1-D4）。卫星图像证实的详细露头测绘和结构分析表明，该地区的美里、冈瓦纳和下西瓦利克岩石序列被两组 NW 和 NE 走向的交叉断层带穿越，厚度约为 70-100 m，可测绘~ 70 公里。交叉断层在 Daring 地区附近呈 NW 走向，而在 Gensi 附近的西部，则呈 NE 走向。最西端的断层向右滑动，最东端的 Daring 向左滑。这些横向断层抵消了 MBT：西部断层为 0.52-0.59 公里，东部断层为 0.58-1.41 公里。Gondwana 层序中的变形可能被限制为同喜马拉雅（即印度-亚洲碰撞事件）。由于后始新世印缅碰撞，随后是来自 E/ESE 的压缩。印度-亚洲和印度-缅甸联合压缩的最终阶段表现为强烈的 NE 向压缩，右向 Reidal 剪切在该区域的横向共轭断层带中发展，向 SE 位移最大。地震数据的聚类表明研究区MBT的N和S都在30-80 km深度内记录了事件（M≥6）。更多，