Palaeoposition of the Seychelles microcontinent in relation to the Deccan Traps and the Plume Generation Zone in Late Cretaceous-Early Palaeogene time

The Early Palaeogene magmatic rocks of North and Silhouette Islands in the Seychelles contain clues to the Cenozoic geodynamic
puzzle of the Indian Ocean, but have so far lacked precise geochronological data and palaeomagnetic constraints. New 40Ar/39Ar and U–Pb dates demonstrate that these rocks were emplaced during magnetochron C28n; however, 40Ar/39Ar and palaeomagnetic data from Silhouette indicate that this complex experienced a protracted period of cooling. The Seychelles
palaeomagnetic pole (57.55°S and 114.22°E; A9512.3°, N=14) corresponds to poles of similar ages from the Deccan Traps after being corrected for a clockwise rotation of 29.4°±12.9°.
This implies that Seychelles acted as an independent microplate between the Indian and African plates during and possibly
after C27r time, confirming recent results based on kinematic studies. Our reconstruction confirms that the eruption of the
Deccan Traps, which affected both India and the Seychelles and triggered continental break-up, can be linked to the present
active Reunion hotspot, which is being sourced as a deep plume from the Plume Generation Zone.

塞舌尔群岛北岛和轮廓岛早始新世火成岩蕴含着解决印度洋新生代地球动力学之谜的线索，然而迄今为止，这些岩石缺乏精确的地质年代数据和古地磁约束。新的40Ar/39Ar和U-Pb测年数据表明，这些岩石是在磁chrono C28n期间形成的；然而，来自轮廓岛的40Ar/39Ar和古地磁数据显示，这一复杂地质体经历了一段持续的冷却期。经过对顺时针旋转29.4°±12.9°的校正后，塞舌尔古地磁极（57.55°S和114.22°E；A9512.3°，N=14）与德干高原火山群中相似年龄的极点相对应。这表明塞舌尔在C27r时期及其之后可能作为印度板块和非洲板块之间的独立微板块存在，证实了基于运动学研究的最新成果。我们的重建确认，德干高原火山的爆发，影响了印度和塞舌尔，并触发了大陆破裂，可以与现今活跃的留尼汪热点联系起来，该热点源自羽流生成区的深部羽流。