Jurassic Sedimentary Basin in Sri Lanka: Knowns and Unknowns. AOGS meeting

Abstract

<p>Over 90% of Sri Lanka consists of high-grade metamorphic rocks, while a few sedimentary outcrops provide rare but significant information to reconstruct the paleoenvironments of this island nation. For example, the Jurassic strata from the Tabbowa Basin have allowed us to understand the Mesozoic world along the ancient margin of Gondwana. Since the early 20^th century, abundant plants, including conifer, cycad, and fern, have been discovered in the Tabbowa beds. Additionally, diverse assemblages of insect trace fossils were found on the surface of these plant fossils, making it possible to discuss the plant-insect co-evolution further and the Jurassic ecosystems in general. However, the systematic study of these findings needs to be improved. Furthermore, the radiometric age determinations for these fossil-rich sedimentary rocks still need to be improved due to the limitations of suitable dating materials from this area. The long-term plan of this study is to conduct detailed geological, chronological, and paleontological investigations in the Tabbowa Basin. The result is expected to answer critical and fundamental questions, including the stratigraphic correlations among these Sri Lankan strata and other contemporaneous deposits in India and Australia and the post-Gondwana history of Sri Lanka. </p>