Abstract The onset of timing and the model of the India-Eurasia collision are strongly debated based on continental works, without systematic marine tectonic constraints. Two aseismic ridges, the Laccadives-Maldives-Chagos Ridge (LMCR) formed after the Deccan volcanism in western India and the Ninetyeast Ridge (NER) formed after the emplacement of the Rajmahal Traps in eastern India are prominent features in the Northeast Indian Ocean. The onset of a major and steady increase in magma production rates along the aseismic ridge associated with the significant slowdown of the northward moving Indian Plate is a likely indicator of the onset of the India-Eurasia collision. Using gravity-derived crustal thickness, we calculated the magma production rates along the LMCR and the NER, respectively. The steady increasing magma production rate along the LMCR and a southwestward jump of the Central Indian Ridge constrained the “soft” (India-island arc) and “hard” (India-Eurasia) collisions between western India and Eurasia to 50–52 Ma and ~41 Ma, respectively. The steady increasing magma production rate along the NER and the formation of the Mammerickx Microplate constrained the soft collision between eastern India and Eurasia to 47–49 Ma, and the extinction of the Wharton Ridge constrained the hard collision between eastern India and Eurasia to 38 Ma. Both the soft and hard collisions between western India and Eurasia are ~3 Myr earlier than the soft and hard collisions between eastern India and Eurasia, respectively. With systematic marine tectonic constraints, a two-stage eastward diachronous model of the India-Eurasia collision was proposed.

中文翻译：

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印度-欧亚大陆碰撞两阶段东向历时模式：来自东北印度洋板块内构造记录的约束

摘要 印度-欧亚大陆碰撞的发生时间和模型是基于大陆工作的激烈争论，没有系统的海洋构造约束。印度西部德干火山作用后形成的拉卡迪夫-马尔代夫-查戈斯海脊（LMCR）和印度东部拉杰马哈尔圈闭就位后形成的九东海脊（NER）两条地震脊是东北印度洋的突出特征。与向北移动的印度板块显着放缓相关的沿抗震脊的岩浆生产率开始出现重大而稳定的增长，这可能是印度-欧亚大陆碰撞开始的一个迹象。使用重力衍生的地壳厚度，我们分别计算了沿 LMCR 和 NER 的岩浆生产速率。LMCR 沿线岩浆产量稳步上升和中印度洋脊向西南跃迁，将印度西部和欧亚大陆之间的“软”（印度-岛弧）和“硬”（印度-欧亚）碰撞限制在 50-52 Ma 和分别为~41 Ma。NER沿线岩浆产量稳步增加和Mammerickx微板块的形成将印度东部与欧亚大陆的软碰撞时间限制在47-49 Ma，沃顿海脊的灭绝将印度东部与欧亚大陆之间的硬碰撞时间限制在38 Ma . 印度西部和欧亚大陆之间的软碰撞和硬碰撞分别比印度东部和欧亚大陆之间的软碰撞和硬碰撞早约 3 Myr。在系统的海洋构造约束下，