UCL  IRIS
Institutional Research Information Service
UCL Logo
Please report any queries concerning the funding data grouped in the sections named "Externally Awarded" or "Internally Disbursed" (shown on the profile page) to your Research Finance Administrator. Your can find your Research Finance Administrator at http://www.ucl.ac.uk/finance/research/post_award/post_award_contacts.php by entering your department
Please report any queries concerning the student data shown on the profile page to:

Email: portico-services@ucl.ac.uk

Help Desk: http://www.ucl.ac.uk/ras/portico/helpdesk
Publication Detail
The late Quaternary slip-rate of the Har-Us-Nuur fault (Mongolian Altai) from cosmogenic 10Be and luminescence dating
  • Publication Type:
    Journal article
  • Publication Sub Type:
    Journal Article
  • Authors:
    Nissen E, Walker RT, Bayasgalan A, Carter A, Fattahi M, Molor E, Schnabel C, West AJ, Xu S
  • Publication date:
    15/09/2009
  • Pagination:
    467, 478
  • Journal:
    Earth and Planetary Science Letters
  • Volume:
    286
  • Issue:
    3-4
  • Status:
    Published
  • Print ISSN:
    0012-821X
Abstract
The Altai range (western Mongolia) accommodates NNE-SSW shortening across the northern India-Eurasia collision zone by dextral slip on faults trending NNW-SSE, and anticlockwise, vertical-axis rotations of fault-bounded blocks. However, fault slip-rates and the way in which faulting evolves over time are poorly understood, and form the motivation for this study. We focussed on the Har-Us-Nuur fault, a major transpressional fault bounding the eastern margin of the Altai. Three abandoned alluvial fan surfaces, each displaced right-laterally by the fault, were targeted for dating with cosmogenic 10Be and quartz optically stimulated luminescence (OSL). The first surface (A2) shows an exponential decrease in 10Be with increasing depth, with a significant inherited component. Modelling this profile yielded a minimum age of 74.1 ka. Material from the same sampling pit was dated at ~ 19 ka with OSL, but we consider this younger age to be incorrect, possibly due to feldspar contamination or abnormal quartz OSL characteristics. The A2 surface is displaced by 175 m, implying a (maximum) dextral slip-rate of 2.4 ± 0.4 mm yr- 1. A second fan surface (F1) was dated at ~ 6 ka with OSL and shows little variation in 10Be with depth, consistent with this young age. The inherited component is higher than for A2, indicating contrasting levels of inheritance for different periods of fan aggradation. A final surface (F2) shows scattered 10Be concentrations and lacks material suitable for OSL, so cannot be dated precisely. Using the total vertical displacement across the fault, we place the initiation of movement on the fault at ~ 2 Ma, significantly later than the late Oligocene to Miocene (28-5 Ma) onset of shortening in the Altai region. This suggests that deformation in the Altai has widened over time to incorporate new faults at the range margins (such as Har-Us-Nuur), possibly because older faults in the range interior have rotated about vertical axes into orientations that require work to be done against gravity. © 2009 Elsevier B.V. All rights reserved.
Publication data is maintained in RPS. Visit https://rps.ucl.ac.uk
 More search options
There are no UCL People associated with this publication
University College London - Gower Street - London - WC1E 6BT Tel:+44 (0)20 7679 2000

© UCL 1999–2011

Search by