A modern pulse of ultrafast exhumation and diachronous crustal melting in the Nanga Parbat Massif

Victor E Guevara; Andrew J Smye; Mark J Caddick; Michael P Searle; Telemak Olsen; Lisa Whalen; Andrew R C Kylander-Clark; Michael J Jercinovic; David J Waters

doi:10.1126/sciadv.abm2689

A modern pulse of ultrafast exhumation and diachronous crustal melting in the Nanga Parbat Massif

Sci Adv. 2022 Aug 5;8(31):eabm2689. doi: 10.1126/sciadv.abm2689. Epub 2022 Aug 5.

Authors

Affiliations

¹ Geology Department, Amherst College, 220 South Pleasant Street, Amherst, MA 01002, USA.
² Department of Geosciences, Pennsylvania State University, 332 Deike Building, University Park, PA 16802, USA.
³ Department of Geosciences, Virginia Tech, 4044 Derring Hall, 926 W. Campus Drive, Blacksburg, VA 24061, USA.
⁴ Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
⁵ Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK.
⁶ Geology Department, Western Washington University, 516 High Street, Bellingham, WA 98225, USA.
⁷ Department of Earth Science, University of California, Santa Barbara, 1006 Webb Hall, Santa Barbara, CA 93106, USA.
⁸ Department of Geosciences, University of Massachusetts, 627 North Pleasant Street, Amherst, MA 01003, USA.

Abstract

We combine monazite petrochronology with thermal modeling to evaluate the relative roles of crustal melting, surface denudation, and tectonics in facilitating ultrafast exhumation of the Nanga Parbat Massif in the western Himalayan syntaxis. Our results reveal diachronous melting histories between samples and a pulse of ultrafast exhumation (9 to 13 mm/year) that began ~1 Ma and was preceded by several million years of slower, but still rapid, exhumation (2 to 5 mm/year). Recent studies show that an exhumation pulse of similar timing and magnitude occurred in the eastern Himalayan syntaxis. A synchronous exhumation pulse in both Himalayan syntaxes suggests that neither erosion by rivers and/or glaciers nor a pulse of crustal melting was a primary trigger for accelerated exhumation. Rather, our results, combined with those of recent studies in the eastern syntaxis, imply that larger-scale tectonic processes impose the dominant control on the current tempo of rapid exhumation in the Himalayan syntaxes.