10.6084/m9.figshare.3453446.v1 A. Licht A. Licht C. France-Lanord C. France-Lanord L. Reisberg L. Reisberg C. Fontaine C. Fontaine Aung Naing Soe Aung Naing Soe J.-J. Jaeger J.-J. Jaeger A palaeo Tibet–Myanmar connection? Reconstructing the Late Eocene drainage system of central Myanmar using a multi-proxy approach Geological Society of London 2016 petrographic data source area palaeo Tsangpo drainage Tibetan provinces share magmatic arc source Irrawaddy River basement material Burmese margin hypothesis Palaeogene Yaw Formations Isotopic analysis Asian drainage patterns Central Myanmar Asian margin Eocene drainage system bulk sediments Indian Ocean lithological features Geology 2016-06-21 11:25:21 Journal contribution https://geolsoc.figshare.com/articles/journal_contribution/A_palaeo_Tibet_Myanmar_connection_Reconstructing_the_Late_Eocene_drainage_system_of_central_Myanmar_using_a_multi-proxy_approach/3453446 <p>Strain resulting from the collision of India with Asia has caused fundamental changes to Asian drainage patterns, but the timing and nature of these changes are poorly understood. One frequently proposed hypothesis involves the connection of the palaeo Tsangpo drainage to a precursor to the Irrawaddy River of central Myanmar in the Palaeogene. To test this hypothesis, we studied the provenance of Palaeogene fluvio-clastic sedimentary rocks that crop out in central Myanmar, namely the Late Middle Eocene–Early Oligocene Pondaung and Yaw Formations. Isotopic analysis on bulk-rock and petrographic data indicate a primary magmatic arc source, and a secondary source composed of recycled, metamorphosed basement material. Although the exact location of both sources is hardly distinguishable because Burmese and Tibetan provinces share common lithological features, the presence of low-grade metamorphic fragments, the heterogeneity in Sr–Nd isotopic values of bulk sediments and westward-directed palaeoflow orientations indicate a proximal source area located on the eastern Asian margin. Central Myanmar was the locus of westward-prograding deltas opening into the Indian Ocean, supplied by the unroofing of an Andean-type cordillera that extended along the Burmese margin. We found no evidence to support a palaeo Tsangpo–Irrawaddy River, at least during the Late Eocene. </p>