TY - JOUR

T1 - Contrasting granitic magmatism of the Kalba fold belt (East Kazakhstan)

T2 - Evidence for Late Paleozoic post-orogenic events

AU - Kuibida, M. L.

AU - Dyachkov, B. A.

AU - Vladimirov, A. G.

AU - Kruk, N. N.

AU - Khromykh, S. V.

AU - Kotler, P. D.

AU - Rudnev, S. N.

AU - Kruk, E. A.

AU - Kuibida, Y. V.

AU - Oitseva, T.

N1 - Publisher Copyright: © 2018 Elsevier Ltd

PY - 2019/5/15

Y1 - 2019/5/15

N2 - The paper presents new original data and a review of previous studies on the Late Carboniferous – Early Permian granitoids of the Kunush and Kalguty intrusive complexes from the Kalba fold belt (East Kazakhstan). These rocks formed at the initial post-collisional stage of the Irtish-Zaisan orogen in the western Central Asian Orogenic Belt (CAOB). The granitoids form isometric or NW linear intrusions inside the Late Devonian - Early Carboniferous metasediments which overlap the accretionary lithology of the Kalba fold belt in front of the Altai active margin of the Siberian continent. These granitoids contain zircon grains with U-Pb ages of ca.308–291 Ma, synchronous with the peak post-orogenic magmatic event at ∼300 Ma in the CAOB. The Kunush high-Na granitoids, with high SiO2 (67–72%) and Al2O3 (15–18%) contents and the Na2O/K2O ratio (1.94–6.43), and low HREEs (Yb = 0.22–0.93 ppm) but moderate Sr/Y ratios (47–179), Mg# (35–55) and Ni, Cr, are generally common to high-Al TTG-series with non-subduction geochemical signatures. The Kalguty granitoids mostly belong to calc-alkalic to subalkalic high-K series, have non-corundum CIPW-norm compositions and mainly weakly peraluminous (ASI = 0.97–1.09) characteristics. Their Fe∗ = 0.7–1 at 62–74 wt.% SiO2 and relatively high Y/Nb (2–4) and Rb/Nb (9–18) ratios are similar to transitional compositions reported for fractionated I- and A2-type post-orogenic granites worldwide. The Kunush high-Na and Kalguty high-K granitoids formed at different depths in the crust and the parent melts were derived from metabasaltic (MORB; P = 10–15 kbar) and metagranitic (TTG-like; P < 10 kbar) protoliths, respectively. We propose that relaxation of tangential compression after oblique collision and the following thermal impact of mafic magma that acted simultaneously at different crustal depths, along with decompressional partial melting, may be a basic petrological scenario for synchronous formation of geochemically different granitoids.

AB - The paper presents new original data and a review of previous studies on the Late Carboniferous – Early Permian granitoids of the Kunush and Kalguty intrusive complexes from the Kalba fold belt (East Kazakhstan). These rocks formed at the initial post-collisional stage of the Irtish-Zaisan orogen in the western Central Asian Orogenic Belt (CAOB). The granitoids form isometric or NW linear intrusions inside the Late Devonian - Early Carboniferous metasediments which overlap the accretionary lithology of the Kalba fold belt in front of the Altai active margin of the Siberian continent. These granitoids contain zircon grains with U-Pb ages of ca.308–291 Ma, synchronous with the peak post-orogenic magmatic event at ∼300 Ma in the CAOB. The Kunush high-Na granitoids, with high SiO2 (67–72%) and Al2O3 (15–18%) contents and the Na2O/K2O ratio (1.94–6.43), and low HREEs (Yb = 0.22–0.93 ppm) but moderate Sr/Y ratios (47–179), Mg# (35–55) and Ni, Cr, are generally common to high-Al TTG-series with non-subduction geochemical signatures. The Kalguty granitoids mostly belong to calc-alkalic to subalkalic high-K series, have non-corundum CIPW-norm compositions and mainly weakly peraluminous (ASI = 0.97–1.09) characteristics. Their Fe∗ = 0.7–1 at 62–74 wt.% SiO2 and relatively high Y/Nb (2–4) and Rb/Nb (9–18) ratios are similar to transitional compositions reported for fractionated I- and A2-type post-orogenic granites worldwide. The Kunush high-Na and Kalguty high-K granitoids formed at different depths in the crust and the parent melts were derived from metabasaltic (MORB; P = 10–15 kbar) and metagranitic (TTG-like; P < 10 kbar) protoliths, respectively. We propose that relaxation of tangential compression after oblique collision and the following thermal impact of mafic magma that acted simultaneously at different crustal depths, along with decompressional partial melting, may be a basic petrological scenario for synchronous formation of geochemically different granitoids.

KW - Central Asian Orogenic Belt

KW - Hot shear system

KW - Irtysh-Zaisan orogen

KW - Kunush-Kalguty granitoids

KW - Post-collision magmatism

KW - S-TYPE GRANITES

KW - A-TYPE GRANITES

KW - NORTHERN WEST JUNGGAR

KW - NW CHINA

KW - TECTONIC IMPLICATIONS

KW - I-TYPE

KW - CALC-ALKALINE

KW - TRONDHJEMITE-GRANODIORITE TTG

KW - PHASE-RELATIONS

KW - ASIAN OROGENIC BELT

UR - http://www.scopus.com/inward/record.url?scp=85052804269&partnerID=8YFLogxK

U2 - 10.1016/j.jseaes.2018.08.027

DO - 10.1016/j.jseaes.2018.08.027

M3 - Article

AN - SCOPUS:85052804269

VL - 175

SP - 178

EP - 198

JO - Journal of Asian Earth Sciences

JF - Journal of Asian Earth Sciences

SN - 1367-9120

ER -