Kinematic implications of regional 40Ar/39Ar ages, east-central Nepal. (1st April 2019)

• Record Type: Journal Article
• Authors: Larson, Kyle P.; Camacho, Alfredo; Kumar, K.C.; Shrestha, Sudip
• Is Part Of: Journal of Asian earth sciences. Volume 172(2019)
• Page Start: 383
• Page End: 392
• Publication Date: 2019-04-01
• Subjects: Himalaya -- 40Ar/39Ar Geochronology -- Kinematics -- Nepal; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2018.09.023
• Languages: English
• ISSNs: 1367-9120

Abstract

Graphical abstract: Highlights: New regional thermochronologic data from across Nepal. 40 Ar/ 39 Ar data outline a 'u-shaped' pattern from south to north. Results outline an out-of-sequence thrust fault, consistent with previous modelling. Abstract: This study presents new 40 Ar/ 39 Ar ages from across the Himalaya in east-central Nepal. 40 Ar/ 39 Ar ages from the Mahabharat region, the southernmost and structurally lowest part of the study area, range between 27.5 and 17.3 Ma while those from the High Himalaya, the northernmost, and structurally highest part of the study area range from 17.7 to 17.4 Ma. These two areas bracket a middle portion characterized by younger ages that range between 8.6 and 14.3 Ma, and cluster around ∼10 Ma. These new dates outline a 'U-shaped' pattern across the region that is interpreted to reflect cooling facilitated by out-of-sequence motion across the Upper Tama Kosi Thrust, in agreement with previous work in the area. The results presented herein are also consistent with published model cooling predictions and highlight the potential importance of late, lower temperature deformation on the present geometries of the exhumed, former metamorphic core exposed mountain belts around the globe.