• Fossil wood flora from the Siwalik Group of Arunachal Pradesh, India and its climatic and phytogeographic significance

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    • Keywords

       

      Megaflora; systematics; Neogene; northeast India; palaeoclimate.

    • Abstract

       

      The plant fossil records from the Siwalik Group of Arunachal Pradesh, India are far from satisfactory due to remoteness and dense vegetation of the area. We report seven fossil woods of which three belong to the Middle Siwalik (Subansiri Formation), while the rest are from the Upper Siwalik (Kimin Formation). The modern analogues of the fossils from the Middle Siwalik are Lophopetalumlittorale (Celastraceae), Afzelia-Intsia and Sindora siamensis (Fabaceae) and from the Upper Siwalik are Miliusa velutina (Annonaceae), Calophyllum tomentosum and Kayea (Calophyllaceae) and Diospyros melanoxylon (Ebenaceae). The dominance of diffuse porosity in the fossil woods indicates a tropicalclimate with low seasonality (little variation) in temperature, while a high proportion of large vessels and simple perforation plates in the assemblage infer high precipitation during the deposition of the sediments. The aforesaid inference is in strong agreement with the previous quantitative reconstruction based on fossil leaves. Several modern analogues of the fossil taxa are now growing in low latitudes possibly due to an increase in seasonality (increased variation) in temperature caused by the rising Himalaya.

    • Author Affiliations

       

      Gaurav Srivastava1 R C Mehrotra1 C Srikarni2

      1. Birbal Sahni Institute of Palaeosciences, 53 University Road, Lucknow 226 007, India.
      2. Geological Survey of India, Sector 10A, Gandhinagar 282 010, India.
    • Dates

       
  • Journal of Earth System Science | News

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