• R C Mehrotra

      Articles written in Journal of Earth System Science

    • Rhizopalmoxylon nypoides – a new palm root from the Deccan Intertrappean beds of Sagar, Madhya Pradesh, India

      P K Kathal Rashmi Srivastava R C Mehrotra P O Alexander

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      A new species of fossil palm rhizome having root-mat under the organ genus Rhizopalamoxylon (Rhizopalmoxylon nypoides sp. nov.) is reported. The specimen shows the closest resemblance with the modern monotypic genus Nypa Wurmb of the Arecaceae. The specimen was collected from the late Maastrichtian–early Danian sediments of Deccan Intertrappean beds, Mothi, Sagar district, Madhya Pradesh, India. Nypa is a mangrove palm naturally found in estuaries and swamps of the tropical region and represents one of the oldest records of the genus from the Deccan Intertrappean beds of centralIndia. The abundance of palms, including Nypa and previously recorded coastal and mangrove elementssuch as Acrostichum, Barringtonia, Cocos, Sonneratia and marine algae (Distichoplax and Peyssonellia)from the Deccan Intertrappean beds indicate marine influence and existence of tropical rainforestecosystem in the vicinity of fossil locality in contrast to the deciduous forests occurring there at present.

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

      Gaurav Srivastava R C Mehrotra C Srikarni

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      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.

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