Riser diachroneity, lateral erosion, and uncertainty in rates of strikeslip faulting: A case study from Tuzidun along the Altyn Tagh Fault, NW China

Ryan D. Gold, Eric Cowgill, Ramon Arrowsmith, John Gosse, Xuanhua Chen, Xiao Feng Wang

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

At late Quaternary timescales, offset fluvial terrace risers are among the most common landforms used to determine rates of strike-slip faulting. Although diachroneity in the age of riser segments on opposite sides of the fault has been noted previously, an unexplored source of uncertainty associated with deriving slip rates from these markers centers on quantifying the size of the displacement uncertainty such diachroneity introduces. To evaluate the impact of riser diachroneity, we investigated the Tuzidun site (37.73°N, 86.72°E) along the Cherchen He reach of the active central Altyn Tagh Fault. The east bank of the channel is flanked by a left-laterally offset terrace riser. While the measured offset is 54 ± 3 m, geochronologic measurements and analysis of riser topography indicate that the downstream riser segment formed between 6.0 ± 0.8 ka and 5.7 ± 0.4 ka, while the upstream riser segment may have been laterally refreshed as recently as 0.5 ± 0.2 ka. A valley wall on the west bank of the channel places a maximum limit of 38 ± 6 m on the amount of possible lateral erosion of the upstream riser. This bound, in turn, limits the total offset since formation of the downstream riser to range from 54 ± 3 to 89 ± 7 m. Together, these observations bracket the millennial Altyn Tagh Fault slip rate to range from 9.0 ± 1.3 to 15.5 ± 1.7 mm a-1. More generally, this investigation shows that the observed riser displacement does not necessarily correlate with the age of either riser segment (downstream or upstream of the fault) in cases where one segment is displaced while the other is subjected to lateral erosion. If this diachroneity goes undetected, erroneous slip rate measurements are likely to result.

Original languageEnglish (US)
Article numberB04401
JournalJournal of Geophysical Research: Solid Earth
Volume114
Issue number4
DOIs
StatePublished - Apr 4 2009

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risers
Faulting
riser
erosion
Erosion
China
faulting
Fault slips
Landforms
Topography
slip rate
slip
upstream
terrace
Uncertainty
rate
landforms
fault slip
brackets
markers

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Riser diachroneity, lateral erosion, and uncertainty in rates of strikeslip faulting : A case study from Tuzidun along the Altyn Tagh Fault, NW China. / Gold, Ryan D.; Cowgill, Eric; Arrowsmith, Ramon; Gosse, John; Chen, Xuanhua; Wang, Xiao Feng.

In: Journal of Geophysical Research: Solid Earth, Vol. 114, No. 4, B04401, 04.04.2009.

Research output: Contribution to journalArticle

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