Details
Original language | English |
---|---|
Pages (from-to) | 100-113 |
Number of pages | 14 |
Journal | Earth and Planetary Science Letters |
Volume | 509 |
Early online date | 11 Jan 2019 |
Publication status | Published - 1 Mar 2019 |
Abstract
Active thrust faulting at the front of the Qilian Shan accommodates the northeastward growth of the Tibetan Plateau, however, the lifespan of individual faults and their slip history on different timescales remain largely unknown. Here, we show that the main range-bounding thrust fault of the western Qilian Shan has accrued tectonic slip at an almost constant rate during the last ∼200 ka, and possibly since fault initiation in the mid-Miocene. Our finding is based on 10 Be ages from a flight of five deformed fluvial terraces along the Hongshuiba river, which constrain the vertical slip rate of the Qilian Shan frontal thrust to be 1.2±0.1 m/ka during the last 200 ka. With a fault dip of 30±5° constrained by seismic reflection data, we obtain a horizontal shortening rate of 2.0±0.3 m/ka. This value is consistent with both the short-term shortening rate of 1.7±0.3 mm/a derived from GPS data and the long-term shortening rate of 2.1±0.4 m/ka, which is based on a balanced geological cross-section. The latter provides a total shortening estimate of 25±3 km since the thrust fault initiated 12±2 Ma ago. The agreement between the shortening rates on the range of timescales between 10 0 and 10 7 years suggests that the western Qilian Shan frontal thrust has slipped at a steady rate since its initiation and implies that this fault is the main structure responsible for the growth of the western Qilian Shan.
Keywords
- Qilian Shan, active faulting, cosmogenic Be, fault scarp, fluvial terrace, slip rate
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
- Earth and Planetary Sciences(all)
- Earth and Planetary Sciences (miscellaneous)
- Earth and Planetary Sciences(all)
- Space and Planetary Science
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In: Earth and Planetary Science Letters, Vol. 509, 01.03.2019, p. 100-113.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - A constant slip rate for the western Qilian Shan frontal thrust during the last 200 ka consistent with GPS-derived and geological shortening rates
AU - Hetzel, Ralf
AU - Hampel, Andrea
AU - Gebeken, Pia
AU - Xu, Qiang
AU - Gold, Ryan
N1 - This paper benefited from thoughtful comments by Marie-Luce Chevalier and an anonymous reviewer that led to significant improvements of the final manuscript. We are grateful to Jessica Thompson Jobe for insightful comments on an early version of this manuscript. We thank A. Niehus for her help during preparation of the 10Be samples, A. Reschka for ICP-OES analysis of the quartz samples, and R. Wolff for his contribution to data analysis. We gratefully acknowledge funding for fieldwork and AMS.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - Active thrust faulting at the front of the Qilian Shan accommodates the northeastward growth of the Tibetan Plateau, however, the lifespan of individual faults and their slip history on different timescales remain largely unknown. Here, we show that the main range-bounding thrust fault of the western Qilian Shan has accrued tectonic slip at an almost constant rate during the last ∼200 ka, and possibly since fault initiation in the mid-Miocene. Our finding is based on 10 Be ages from a flight of five deformed fluvial terraces along the Hongshuiba river, which constrain the vertical slip rate of the Qilian Shan frontal thrust to be 1.2±0.1 m/ka during the last 200 ka. With a fault dip of 30±5° constrained by seismic reflection data, we obtain a horizontal shortening rate of 2.0±0.3 m/ka. This value is consistent with both the short-term shortening rate of 1.7±0.3 mm/a derived from GPS data and the long-term shortening rate of 2.1±0.4 m/ka, which is based on a balanced geological cross-section. The latter provides a total shortening estimate of 25±3 km since the thrust fault initiated 12±2 Ma ago. The agreement between the shortening rates on the range of timescales between 10 0 and 10 7 years suggests that the western Qilian Shan frontal thrust has slipped at a steady rate since its initiation and implies that this fault is the main structure responsible for the growth of the western Qilian Shan.
AB - Active thrust faulting at the front of the Qilian Shan accommodates the northeastward growth of the Tibetan Plateau, however, the lifespan of individual faults and their slip history on different timescales remain largely unknown. Here, we show that the main range-bounding thrust fault of the western Qilian Shan has accrued tectonic slip at an almost constant rate during the last ∼200 ka, and possibly since fault initiation in the mid-Miocene. Our finding is based on 10 Be ages from a flight of five deformed fluvial terraces along the Hongshuiba river, which constrain the vertical slip rate of the Qilian Shan frontal thrust to be 1.2±0.1 m/ka during the last 200 ka. With a fault dip of 30±5° constrained by seismic reflection data, we obtain a horizontal shortening rate of 2.0±0.3 m/ka. This value is consistent with both the short-term shortening rate of 1.7±0.3 mm/a derived from GPS data and the long-term shortening rate of 2.1±0.4 m/ka, which is based on a balanced geological cross-section. The latter provides a total shortening estimate of 25±3 km since the thrust fault initiated 12±2 Ma ago. The agreement between the shortening rates on the range of timescales between 10 0 and 10 7 years suggests that the western Qilian Shan frontal thrust has slipped at a steady rate since its initiation and implies that this fault is the main structure responsible for the growth of the western Qilian Shan.
KW - Qilian Shan
KW - active faulting
KW - cosmogenic Be
KW - fault scarp
KW - fluvial terrace
KW - slip rate
UR - http://www.scopus.com/inward/record.url?scp=85059812051&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2018.12.032
DO - 10.1016/j.epsl.2018.12.032
M3 - Article
VL - 509
SP - 100
EP - 113
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
SN - 0012-821X
ER -