Cenozoic deep crust in the Pamir

Schmidt, J; Hacker, Bradley R.; Ratschbacher, Lothar; Stübner, Konstanze; Stearns, Michael A.; Kylander‐Clark, Andrew; Cottle, John M.; Alexander, A.; Webb, A. Alexander G.; Gehrels, George E.; Minaev, V.

doi:10.1016/j.epsl.2011.10.034

Cited by 124 publications

(242 citation statements)

References 48 publications

Supporting

Mentioning

232

Contrasting

Unclassified

Order By: Relevance

“…The domes cover up to 30 % of the Pamir and expose crystalline basement and metamorphic rocks (Vlasov et al, 1991;Brunel et al, 1994;Schwab et al, 2004;Robinson Schmidt et al, 2011;Stübner et al, 2013) The Kurgovat Dome of the Northern Pamir consists of high-grade metamorphosed Triassic rocks. The domes in the Central Pamir (Yazgulom, Sarez, Muskol and Shatput domes; Fig.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…The domes in the Central Pamir (Yazgulom, Sarez, Muskol and Shatput domes; Fig. 1) and the Southern Pamir (Shakhdara and Alichur domes) have exhumed high-grade metamorphic rocks of Oligocene-Miocene age (Schmidt et al, 2011;Stübner et al, 2013). The Pamir gneiss domes relate to orogen-wide exhumation between ∼21 Myr and 13 Myr (Lukens et al, 2012).…”

Section: Tectonic Settingmentioning

confidence: 99%

“…The topography of the Pamir is dominated by a series of Oligo-Miocene domes (Hubbard et al, 1999;Ducea et al, 2003;Schwab et al, 2004;Amidon and Hynek, 2010). The timing and mechanism of dome exhumation and the distribution of neotectonic activity are a focus of research in the Pamir (e.g., Schmidt et al, 2011;Schneider et al, 2013;Sippl et al, 2013;Stübner et al, 2013). The Pamir lies in a climatic transition zone between the Westerlies and the Indian Summer Monsoon (ISM).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Rates of river incision across the main tectonic units of the Pamir identified using optically stimulated luminescence dating of fluvial terraces

et al. 2014

View full text Add to dashboard Cite

Calculated incision rates along the Panj, the main river of the Pamir, are used to investigate any influence by tectonics or climate on the architecture of the river. The depositional ages of Panj river terraces were calculated using optically stimulated luminescence (OSL) dating of terrace sand. Fluvial incision rates were generated by integrating the terrace depositional ages with accurate kinematic GPS measurements of terrace heights above the modern Panj. We investigated 16 terraces along the Panj at the western Pamir margin and one terrace from the Vakhsh River to the north of the Pamir. The results reveal brief periods of fluvial deposition over the past 26 kyr. The oldest Panj terrace depositional ages coincide with early MIS 2 and MIS 2/1 glaciations on the Pamir Plateau. Younger terrace ages have no apparent link with glacial cycles. Terraces with varying heights above the modern Panj at different localities yielded similar depositional ages. This suggests that local conditions have determined fluvial incision rates. Combining all of the terrace measurements, the average incision rate of the Panj over the last 26 kyr has been ∼5.6 mm/yr. A high mean incision rate of ∼7.3 mm/yr was calculated from terraces where the Panj has cut a steep-sided valley through the Shakhdara Dome. Significantly lower incision rates (∼2 -3 mm/yr) were calculated from terraces where the Panj flows along the southern boundaries of the Shakhdara and Yazgulom domes. At those localities, graded segments of the Panj river profile and increased valley widths are indicative of local base levels. Downstream of the Yazgulom Dome, river incision rates are generally lower (∼4 -5 mm/yr) than the Panj average. However, there is one exception where higher incision rates (∼6 mm/yr) were calculated upstream of the Darvaz Fault Zone, a major tectonic feature that forms the western boundary of the Pamir. The Vakhsh river terrace to the north of the Pamir yielded a lower incision rate (∼3 mm/yr) compared to the Panj average. Variation in incision rates along the Panj does not correspond to changes in rock type or river catchment area. Instead, incision rates appear to have been primarily influenced by river capture across the southern and central metamorphic domes of the Pamir. Wherever the Panj cuts these domes it displays a convex river profile. The combination of localized river profile convexity and changes in incision rates across the Pamir domes indicates that the dome boundaries have been active recently.

show abstract

Section: Tectonic Settingmentioning

confidence: 99%

Section: Tectonic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rates of river incision across the main tectonic units of the Pamir identified using optically stimulated luminescence dating of fluvial terraces

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Structural domes expose crystalline basement rocks that are mantled by lower-grade to non-metamorphic cover rocks; these domes cover up to 30 % of the surface exposure of the Pamir (Vlasov et al, 1991;Brunel et al, 1994;Robinson et al, 2004;Schwab et al, 2004;Schmidt et al, 2011;Stübner et al, 2012).…”

Section: Tectonic Setting and Structural Units Of Pamirmentioning

confidence: 99%

“…The Kurgovat dome exposes high-grade rocks metamorphosed in the Triassic (Schmidt et al, 2011). In contrast, the domes in the Central (Yazgulom, Sarez, Muskol and Shatput Domes) and Southern Pamir (ShakhdaraAlichur Dome) exhumed high-grade, middle to lower crustal metamorphic rocks of Cenozoic age ( Fig.…”

Section: Tectonic Setting and Structural Units Of Pamirmentioning

confidence: 99%

Tectonic and climatic forcing on the Panj river system during the Quaternary

Fuchs

Gloaguen

Pohl

2013

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

Surface processes involve complex feedback effects between tectonic and climatic influences in the high mountains of Pamir. The ongoing India-Asia collision provokes the development of east-west-trending mountain ranges that impose structural control on flow directions of the Pamir rivers. The evolving relief is further controlled by strong moisture gradients. The decreasing precipitations from the southern and western margins of the Pamir Plateau to its center, in their turn, control the emplacement of glaciers. Chronologies of glacial records from the Pamir Plateau attest for strong climatic variability during the Quaternary. Corresponding remnants of glacial advances suggest glacial morphodynamic restricted to >4,000 m a.s.l. since marine isotope stage (MIS) 4. The Panj, the trunk river of Pamir, deflects from the predominant westward drainage, connecting its main tributaries at the western margin of the drainage basin. The geometry of the river network and the pattern of incision characterize the Panj as a composite river. River reaches of indicated low incision coincide with west-trending valleys, parallel to domes and their bounding faults. Valley shape ratios reflect increased incision in north-trending sections, but do not match with changes in the catchment geometry or erodibility of rock types. Modelled riverbed profiles distinguish three Panj reaches. The upstream increase in convexity suggests successive river captures in response to local base-level changes. The northward-deflected river reaches link the local base levels, which coincide with the southern boundaries of the Shakhdara and Yazgulom Dome and Darvaz Range. We argue that tectonics plays a large role controlling the drainage system of the Panj and hence surface processes in the Pamir mountains.

show abstract

Partially melted, mica-bearing crust in Central Tibet

2014

View full text Add to dashboard Cite

Surface wave tomography shows that the central Tibetan Plateau (the Qiangtang block) is characterized by S wave speeds as slow as 3.3 km/s at depths from 20-25 km to 45-50 km and S wave radial anisotropy of at least 4% (V SH > V SV ) that is stronger in the west than the east. The depth of the Curie temperature for magnetite inferred from satellite magnetic measurements, the depth of the α-β quartz transition inferred from V P /V S ratios, and the equilibration pressures and temperatures of xenoliths erupted from the middle to deep crust indicate that the Qiangtang crust is hot, reaching 1000°C at the Moho. This inferred thermal gradient crosses the dehydration melting solidi for crustal rocks at 20-30 km depth, implying the presence or former presence of melt in the Tibetan middle to deep crust. These temperatures do not require the wholesale breakdown of mica at these depths, because F and Ti can stabilize mica to at least 1300°C. Petrology suggests, then, that the Qiangtang middle to deep crust consists of a mica-bearing residue from which melt has been extracted or is being extracted. Wave speeds calculated for mica-bearing rocks with a subhorizontal to gently dipping foliation and 2% silicate melt are a good match to the wave speeds and anisotropy observed by seismology.

show abstract

Cenozoic deep crust in the Pamir

Cited by 124 publications

References 48 publications

Rates of river incision across the main tectonic units of the Pamir identified using optically stimulated luminescence dating of fluvial terraces

Rates of river incision across the main tectonic units of the Pamir identified using optically stimulated luminescence dating of fluvial terraces

Tectonic and climatic forcing on the Panj river system during the Quaternary

Partially melted, mica-bearing crust in Central Tibet

Contact Info

Product

Resources

About