Magma mixing of granites at Lianghe: In-situ zircon analysis for trace elements, U-Pb ages and Hf isotopes

Abstract

In this paper, we report an integrated study of trace element, U-Pb age and Hf isotopic composition of zircons from alkali feldspar granites, granodiorites and diorite enclaves in a recently discovered ring complex at Lianghe in western Yunnan, China. The granitoids showed identical U-Pb ages of 127, 115 and 122 Ma, from felsic to mafic, but had different zircon trace elements and Hf isotopic compositions. Trace element content decreased with a gradual increase in ε Hf (t) values of −9.1 to −5.4, −4.5 to 0, and 3.6 to 6.2, respectively. Results indicate that changes in zircon trace elements generally correlate with changes in Hf isotope signatures within single samples and among various granitoids. These relationships reflect the mixing of felsic and mafic magmas. Evidence indicates that depleted mantle-derived mafic magma underplating caused ancient crustal melting, and then formed large-scale granites in Lianghe during the Early Cretaceous. These granodiorites were formed mainly by the mixing of mafic magma and granitic magma.

Tectono-magmatic evolution of the Gaoligong belt, southeastern margin of the Tibetan plateau: Constraints from granitic gneisses and granitoid intrusions

“…Coeval magmatism took place at the Dulongjiang, Fugong, and Lushui areas in the northern Gaoligong belt, and the rocks were named Gaoligong granites by Yang et al (2006) and Xu et al (2012), with ages ranging from 118 to 126 Ma and 121 to 126 Ma, respectively. Similar magmatic rocks were also found in the Lianghe and Tengchong areas located along the margin of the Gaoligong belt (Cong et al, 2011;Li et al, 2012bLi et al, , 2012cQi et al, 2011), with ages of ~120 Ma.…”

Petrogenesis and tectonic setting of the Early Cretaceous granitoids in the eastern Tengchong terrane, SW China: Constraint on the evolution of Meso-Tethys

“…3D). Therefore, based on the mineralogical and geochemical results, we suggest that the Xishanjiao granites are I-type granites, which is consistent with the results reported previously for the Tengchong terrane (Yang et al, 2006;Cong et al, 2011aCong et al, , 2011bQi et al, 2011Qi et al, , 2019Luo et al, 2012;Cao et al, 2014;Zhu et al, 2015Zhu et al, , 2018Fang et al, 2018;Zhang et al, 2018). We have summarized data of the Early Cretaceous igneous rocks from the Tengchong terrane and find that they show similar trends and chemical characteristics.…”

“…Therefore, granites can provide important insights into tectonic settings and crust-mantle interaction within orogenic belts (Xu et al, 2008). Accordingly, the Early Cretaceous granitoids widespread in the Tengchong terrane, SW China, are prime records for understanding their tectonic environments and Sn mineralization related to synchronous magmatism (Cong et al, 2011a(Cong et al, , 2011bQi et al, 2011;Luo et al, 2012;Xu et al, 2012;Cao et al, 2014;Zhu et al, 2015;Xie et al, 2016;Fang et al, 2018;Qi et al, 2019). On the basis of close similarity in geochemical characteristics and chronology of these igneous rocks, geologists proposed that the Tengchong terrane is most likely linked with the Lhasa terrane and experienced similar tectonic histories since the Early Paleozoic (Xu et al, 2008(Xu et al, , 2012Xie et al, 2016;Qi et al, 2019).…”

U–Pb zircon geochronology of basal granite by LA-ICP-MS in Yitong Basin, Northeast China: Implications for origin of limestone

“…Previous studies show that ERR content and distributive patterns of zircon grains can be used to indicate the environment in which the mineral was formed and the chemical composition of melt or fluid that formed the mineral, and that ERR compositions in zircons of various origins differ greatly Cong et al, 2011;Sun and McDonough, 1989). We learned from our research that zircon grains of different origins/types/sampling position yield various chondrite-normalized REE plots.…”