Tibetan uplift controversy

Fun geology controversy of the day - did uplift of the Tibetan plateau predate continental collision?

Most textbooks will tell you that the Himalayas and the Tibetan plateau, which sits greater than 5 km above sea level, began to form some 50 million years ago when the Indian continent began its slow but persistent collision with Eurasia. The uplift of the plateau is thought to be a major player in the long-term global cooling throughout most of the Cenozoic (66 – 0 million years ago). Quite a few geologists, however, want to throw a wrench in this nice little paradigm. They suggest that the plateau was already elevated in the early Cretaceous, when it was much warmer and dinosaurs were still running around doing their thing. England and Searle (1987) suggested that this early uplift could have occurred in a non-collisional, subduction zone setting similar to that responsible for the rise of the central Andean plateau in South America. Murphy et al. (1997) used geologic mapping and chronological constraints to suggest that the majority of Tibetan uplift occurred during the Cretaceous due to collision of an ocean island tectonic block with the continent. A recent study by Hetzel et al. (2011), however, suggests that these earlier studies document evidence only for Cretaceous crustal shortening (squeezing), and not necessarily a sustained elevated plateau. They interpret thermochronologic and cosmogenic nuclide data to indicate that a low-elevation fluvial system was established by 50 million years ago, when the Indian collision began. They incorporate the early-rise model into a comprehensive model where the Tibetan plateau rose slowly in the Cretaceous, but erosion kept elevations relatively low. They argue that the majority of Tibetan uplift occurred rapidly to its current elevation between 50 and 35 million years ago following continental collision, just like the books say it happened.

 

From figure 2. Heltzel et al., 2013

Sources

England, P., and Searle, M., 1986, The Cretaceous-Tertiary deformation of the Lhasa block and its implications for crustal thickening in Tibet: Tectonics, v. 5, p. 1–14.

Hetzel, R., Dunkl, I., Haider, V., Strobl, M., von Eynatten, H., Ding, L., and Frei, D., 2011, Peneplain formation in southern Tibet predates the India-Asia collision and plateau uplift: Geology, v. 39, p. 983–986.

Murphy, M.A., Yin, A., Harrison, T.M., Dürr, S.B., Chen, Z., and four others, 1997, Did the Indo-Asian collision alone create the Tibetan plateau? Geology, v. 25 (8), p. 719-722.