Growth of the southern Tian Shan-Pamir and its impact on central Asian climate

A high-elevation barrier formed by the Tian Shan and Pamir ranges in Central Asia around 12 million years ago (Ma) effectively blocked westerly moisture, creating a rain shadow that led to desertification in the northwestern Tarim Basin. This finding resolves a long-standing controversy about when hyper-arid conditions developed in the region. Researchers analyzed a continuous stratigraphic section from the southern Tian Shan foreland, combining detrital zircon data, stable isotope compositions (δ18Oc and δ13Cc), structural modeling, and magnetostratigraphy. The study revealed that westerly precipitation was present by 15 Ma but intensified desertification occurred at ca. 12 Ma, coinciding with tectonic deformation in the Pamir and southern Tian Shan. Post-7 Ma, rapid shortening and deformation isolated the study area as a piggy-back basin, decoupling local sedimentologic changes from global climate signals. This work underscores the dominance of tectonics over regional and global climate influences in active settings.

Richter, F., Pearson, J., Vilkas, M., Heermance, R. V., Garzione, C. N., Cecil, M. R., Jepson, G., Moe, A., Xu, J., Liu, L., & Chen, J. (2022). Growth of the southern Tian Shan-Pamir and its impact on central Asian climate. GSA Bulletin. https://doi.org/10.1130/b36471.1