TY - JOUR

T1 - Mantle-triggered intrusions in the western Central Asian Orogenic Belt: implications for the fertilisation of the crust in Tian Shan, Uzbekistan

AU - Choulet, Flavien

AU - Seltmann, Reimar

AU - Divaev, Farid

AU - Shatov, Vitaly

AU - Konopelko, Dmitry

N1 - Funding Information: This study was supported by the EU Framework Programme 7 funded SYNTHESYS Project Grant GB-TAF—3392 (2014) and by NHM’s Centre for Russian and Central EurAsian Mineral Studies (CERCAMS), enabling related visits of Flavien Choulet at the Natural History Museum, London, during 2012-2017. This paper is a contribution under the International Geoscience Program project “Continental construction in Central Asia” (IGCP-592, 2012-17) funded by IUGS and UNESCO, and to the current IGCP-662 “Altaids-Tethysides amalgamation” (2018-23). We acknowledge NHM assistance namely from Mr Tony Wighton for sample preparation, Mr John Spratt for assistance in using SEM and EPMA facilities at NHM London, and the late Prof. Teresa Jeffries for her invaluable help during LA-ICPMS measurement and processing. We thank Wolf-Christian Dullo for editing this manuscript and Jiyuan Yin and an anonymous reviewer for their comments, which led to an increase in the quality of this paper. Publisher Copyright: © 2022, Geologische Vereinigung e.V. (GV).

PY - 2022/11

Y1 - 2022/11

N2 - Mantle intrusive rocks (lamproites and basalts) were collected from different units of the Uzbek Tian Shan, Central Asia to investigate xenoliths and xenocrysts aiming at tracking the shallow or deep nature of the mantle source. Whole-rock geochemistry and petrography revealed that these rocks are mostly of basaltic composition and may contain various exotic materials. These rocks originate from composite mantle magmas; they often result from the mixing between an evolved primary melt and more primitive melts, as indicated by the composition and textures of clinopyroxenes. Olivine, orthopyroxene and spinel mineral geochemistry from xenocrysts and lherzolitic xenoliths is consistent with a shallow mantle source (spinel lherzolite). Trace element content of clinopyroxenes shows LREE depletion supporting the removal of the magma from an undepleted sub-continental lithospheric mantle. The latter one is heterogenous, though and some parts recorded evidence of intense metasomatism. The upwelling asthenospheric magmas, emplacing in trans-lithospheric structures, were probably directly transferred into the crust or just below the crust, without significantly changing the geochemical composition of the sub-continental lithospheric mantle.

AB - Mantle intrusive rocks (lamproites and basalts) were collected from different units of the Uzbek Tian Shan, Central Asia to investigate xenoliths and xenocrysts aiming at tracking the shallow or deep nature of the mantle source. Whole-rock geochemistry and petrography revealed that these rocks are mostly of basaltic composition and may contain various exotic materials. These rocks originate from composite mantle magmas; they often result from the mixing between an evolved primary melt and more primitive melts, as indicated by the composition and textures of clinopyroxenes. Olivine, orthopyroxene and spinel mineral geochemistry from xenocrysts and lherzolitic xenoliths is consistent with a shallow mantle source (spinel lherzolite). Trace element content of clinopyroxenes shows LREE depletion supporting the removal of the magma from an undepleted sub-continental lithospheric mantle. The latter one is heterogenous, though and some parts recorded evidence of intense metasomatism. The upwelling asthenospheric magmas, emplacing in trans-lithospheric structures, were probably directly transferred into the crust or just below the crust, without significantly changing the geochemical composition of the sub-continental lithospheric mantle.

KW - Central Asia

KW - Lamproites

KW - Mantle magma

KW - Tian Shan

KW - Xenocrysts

KW - Xenoliths

UR - http://www.scopus.com/inward/record.url?scp=85125623477&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/9f1d5721-e05f-306b-9be5-7495e383da56/

U2 - 10.1007/s00531-022-02172-7

DO - 10.1007/s00531-022-02172-7

M3 - Article

AN - SCOPUS:85125623477

VL - 111

SP - 2691

EP - 2714

JO - International Journal of Earth Sciences

JF - International Journal of Earth Sciences

SN - 1437-3254

IS - 8

ER -