Late Cenozoic tectonic evolution of the northwestern Tien Shan: New age estimates for the initiation of mountain building

Research Article| December 01, 2001 Late Cenozoic tectonic evolution of the northwestern Tien Shan: New age estimates for the initiation of mountain building M.E. Bullen; M.E. Bullen 1Department of Geosciences, Pennsylvania State University, Deike Building, University Park, Pennsylvania 16801, USA Search for other works by this author on: GSW Google Scholar D.W. Burbank; D.W. Burbank 1Department of Geosciences, Pennsylvania State University, Deike Building, University Park, Pennsylvania 16801, USA Search for other works by this author on: GSW Google Scholar J.I. Garver; J.I. Garver 2Geology Department, Union College, Olin Building, Schenectady, New York 12308, USA Search for other works by this author on: GSW Google Scholar K.Ye. Abdrakhmatov K.Ye. Abdrakhmatov 3Kyrgyz Institute of Seismology, Kyrgyz Academy of Sciences, Asanabai 52/1, Bishkek 720060, Kyrgyzstan Search for other works by this author on: GSW Google Scholar Author and Article Information M.E. Bullen 1Department of Geosciences, Pennsylvania State University, Deike Building, University Park, Pennsylvania 16801, USA D.W. Burbank 1Department of Geosciences, Pennsylvania State University, Deike Building, University Park, Pennsylvania 16801, USA J.I. Garver 2Geology Department, Union College, Olin Building, Schenectady, New York 12308, USA K.Ye. Abdrakhmatov 3Kyrgyz Institute of Seismology, Kyrgyz Academy of Sciences, Asanabai 52/1, Bishkek 720060, Kyrgyzstan Publisher: Geological Society of America Received: 20 Oct 1999 Revision Received: 01 Mar 2000 Accepted: 16 May 2001 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (12): 1544–1559. https://doi.org/10.1130/0016-7606(2001)1132.0.CO;2 Article history Received: 20 Oct 1999 Revision Received: 01 Mar 2000 Accepted: 16 May 2001 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation M.E. Bullen, D.W. Burbank, J.I. Garver, K.Ye. Abdrakhmatov; Late Cenozoic tectonic evolution of the northwestern Tien Shan: New age estimates for the initiation of mountain building. GSA Bulletin 2001;; 113 (12): 1544–1559. doi: https://doi.org/10.1130/0016-7606(2001)1132.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Tien Shan are the quintessential intracontinental range, situated more than 1000 km north of the suture between India and Asia. Their initiation and growth in the Cenozoic, however, remain poorly understood. In this study we present stratigraphic, detrital fission-track, and magnetostratigraphic results that provide a basis for reconstructing the Cenozoic tectonic evolution of the Kyrgyz Range and adjacent Chu basin in the northwestern Tien Shan. Detrital fission-track thermochronology indicates that the northwestern Tien Shan was tectonically quiescent for much of the Cenozoic. Prior to uplift and exhumation in the late Miocene, the Kyrgyz Range was buried by sediments shed from highlands to the south and/or east. Paired bedrock fission-track and U-Th/He ages from a sampling transect of 2.4 km relief demonstrate that rapid exhumation commenced at ca. 11 Ma. Initial thrusting in the hinterland was followed by evaporite accumulation (∼0.4 km/m.y.), which coincided with erosion of the pre–11 Ma strata that mantled the Kyrgyz Range. Between 10 and 3 Ma, bedrock- exhumation rates decreased to <0.3 km/ m.y., while sedimentation rates decelerated initially to ∼0.25 km/m.y. before accelerating to ∼0.4 km/m.y. at 4–5 Ma. Detrital fission-track results indicate that by 4.5 Ma, the top of an exhumed apatite partial annealing zone (PAZ) was exposed in the Kyrgyz Range, corresponding with ∼2 km of total exhumation. Continued exhumation of the Kyrgyz Range resulted in exposure of fully reset rocks from below the exhumed PAZ (∼4–5 km depth) by ca. 1.5 Ma. Fission-track ages from two modern stream samples collected ∼75 km apart along the range front indicate that exhumation in the Kyrgyz Range commenced in the west and then propagated to the east. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.