Age of Initiation of the India‐Asia Collision in the East‐Central Himalaya: A Discussion

Abstract

In their recent article, Zhu et al. (2005) provide new data on the stratigraphy and provenance of the Paleogene terrigenous strata in the Zhepure Shan Range of the Tethyan Himalayas, southern Tibet, using petrographic and geochemical whole-rock and single-grain techniques. Observed changes in the sandstone composition, according to the authors, indicate the onset of the India-Asia collision and the first development of the foreland basin immediately south of the India-Asia suture zone, which occurred at Ma. The authors pre50.6 0.2 sent valuable new geochemical data for the Paleogene clastic rocks in southern Tibet, including their source areas and tectonic affinity, which they use to interpret the geotectonic history of the Tethyan Himalaya. The aim of the present discussion is to point out several erroneous claims and conclusions made by the authors that have a considerable effect on the interpretation of regional stratigraphy, lithofacies, the closing of the Tethys seaway, and the initiation of the India-Asia collision. The authors reject most of the conclusions reached by Wang et al. (2002), which were derived from a study of the same stratigraphic sequence at the same location (Qumiba section; for details, see fig. 1). The location of the section, as given in Wang et al. (2002), was based on a Chinese military map, and the location given by Zhu et al. (2005), using a GPS locator, was not correct, but their section is the same one studied by Wang et al. (2002; see fig. 1). The main objective of the Wang et al. (2002)