The discovery of the oldest rocks in the Kuluketage area and its geological implications

New geochemical and combined zircon U–Pb and Lu–Hf isotopic data of orthogneisses in the northern Altyn Tagh, northern margin of the Tibetan plateau: Implication for Archean evolution of the Dunhuang Block and crust formation in NW China

“…8 (data from Chen et al, 2006Chen et al, , 2013Diwu et al, 2007Diwu et al, , 2011Gao et al, 2011;Guo et al, 2008;Jiang et al, 2010;Jiao et al, 2009;Liu et al, 2008a;Liu et al, 2009Liu et al, , 2013Long et al, 2010Long et al, , 2011aWan et al, 2007;Wu et al, 2008;Yang et al, 2008;Zhang et al, 2006;Zong et al, 2013). This new data set indicates that the NCC experienced several periods of crustal growth in the Archean (Fig.…”

“…Based on the calculation of Hf crustal model ages, our recent study of igneous zircons from Neoarchean and early Paleoproterozoic orthogneisses in the northern TC suggests that this area experienced two periods of crustal growth in the Mesoarchean (2.9-3.3 Ga) and Neoarchean (2.5-2.7 Ga) with two age peaks at 3.18 and 2.61 Ga, respectively (Long et al, 2010). Compared with crustal growth events in the NCC and YC as recorded by limited data at that time, Long et al (2010Long et al ( , 2011a suggested that the northern TC had a different crustal history from that of the other two cratons.…”

“…Because of an extensive cover of desert recent deposits, Precambrian basement rocks are only exposed on the craton margins around the Tarim basin, e.g. the Kuluketage (also named as "Quruqtagh" in the literature) Block in the northeast, the Aksu Block in the northwest, the Tiekelike Block in the southwest and the Dunhuang Block in the east (BGMRX, 1993;Cao et al, 2011;Ge et al, 2012;Guo et al, 2003Guo et al, , 2005He et al, 2012;Hu and Wei, 2006;Hu et al, 2000;Long et al, 2010Long et al, , 2011aLong et al, , 2011bLong et al, , 2012Lu and Yuan, 2003;Lu et al, 2008b;Shu et al, 2011;Xu et al, 2005;Zhang et al, 2007bZhang et al, , 2009Zhang et al, , 2011Zhang et al, , 2012dZhang et al, , 2013aZhu et al, 2011aZhu et al, , 2011b. Among the Precambrian basement, Archean rocks predominantly consist of strongly deformed tonalitic-trondhjemiticgranodioritic orthogneisses (TTG) and metamorphosed supracrustal xenoliths, sparsely exposed along the northern and eastern margins (Zhao and Cawood, 2012 and references therein).…”

“…Orthogneisses of the complex are generally assigned to the TTG suite, and zircon dating shows that these rocks were mainly emplaced during the period 2.65-2.50 Ga (Long et al, 2010(Long et al, , 2011aLu, 1992;Shu et al, 2011;Zhang et al, 2012aZhang et al, , 2012b. Limited Hf isotopic analyses of zircons from these rocks suggest two important crustal growth events in the northern Tarim, namely one in the Paleo-to Mesoarchean (3.3-2.9 Ga) and the other in the Neoarchean (2.7-2.5 Ga) (Long et al, 2010).…”

Petrology and zircon U-Pb dating combined with Hf isotope study of granitic rocks from the Kuluketage Block (Tarim Craton, NW China)

“…It is mainly composed of granitic gneisses with minor amphibolite xenoliths (derived from gabbroic protoliths) (Hu AQ et al 1999; it yielded a SHRIMP U-Pb zircon age of 2601 ± 21 Ma (Zhang et al 2012a) and LA-ICP-MS U-Pb upper intercept zircon age of 2659 ± 15 Ma (Long et al 2011a Feng et al 1995;Lu et al 2002;Zhang et al 2007b). Mesoproterozoic to early Neoproterozoic low-grade metamorphic rocks, including metamorphosed carbonate and clastic metasedimentary rocks, as well as granitoids, are widespread in the area (Feng et al 1995;Lu et al 2008).…”