Acta Geodynamica et Geomaterialia

Title: RATE OF EROSION AND EXHUMATION OF CRYSTALLINE ROCKS IN THE HUNZA KARAKORAM DEFINED BY THE APATITE FISSION TRACK ANALYSIS
Authors: Kořínková Dagmar, Svojtka Martin and Kalvoda Jan
DOI: 10.13168/AGG.2014.0010
Journal: Acta Geodynamica et Geomaterialia, Vol. 11, No. 3 (175), Prague 2014
Full Text: PDF file (9.0 MB)
Keywords: apatite fission-track analysis, exhumation of rocks, erosion, Karakoram
Abstract: Rapid exhumation of rock massifs in the Hunza Karakoram has been caused by collision orogeny as well as intensive and variable climate-morphogenetic processes during the late Cenozoic. Apatite fission-track dating of crystalline rocks gave AFT-ages between 3.9 ± 0.2 Ma to 9.9 ± 0.4 Ma and constrained the period of a rapid exhumation and unroofing as Upper Miocene to Quaternary. Time-temperature curves of the samples show two trends of exhumation rate: the Upper Miocene to Pliocene period of a slow rate of ca. 0.1 km/Ma followed by the Quaternary period of a relative rapid rate of ca. 2.6 km/Ma. The erosion rate reached up to a maximum of ca. 4000 m from the Upper Miocene to the present. The high intensity of recent denudation and transport of weathered and eroded material suggest their long-term influence on the exhumation of deeper parts of the rock massifs during active orogenetic processes in the Hunza Karakoram.