Geochemistry and SHRIMP U–Pb zircon geochronology of the Korla mafic dykes: Constrains on the Neoproterozoic continental breakup in the Tarim Block, northwest China

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

“…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).…”

“…Compared to the NCC and YC, the early Precambrian geology of the TC is poorly studied because of limited exposures along the margins of the Tarim Basin. Although there are some reliable age data for the Tarim basement rocks, little is known about the early geological evolution of the different blocks of the TC (BGMRX, 1993;Guo et al, 2003Guo et al, , 2005Hu and Rogers, 1992;Hu et al, 1997Hu et al, , 2000Long et al, 2010;Lu and yuan, 2003;Lu et al, 2008a;Shu et al, 2011;Zhang et al, 2007aZhang et al, , 2012aZhang et al, , 2012bZhang et al, , 2013aZhu et al, 2011aZhu et al, , 2011bZong et al, 2013). More importantly, whether the entire TC underwent the same evolution and has a uniform Precambrian basement still remains unclear, and this has hampered a better understanding of the tectonic relationship between the TC and the other two Chinese cratons.…”

Geochemistry and zircon ages of mafic dikes in the South Qinling, central China: evidence for late Neoproterozoic continental rifting in the northern Yangtze block

“…Rocks from the lithospheric mantle are commonly characterized by enrichment of LREE and LILE and depletion of Nb and Ta (e.g., Zhao and Zhou 2007;Zhao et al 2010;Zhu et al 2011). Rocks from asthenospheric mantle have trace element patterns similar to most oceanic island basalts and show enrichment of LILEs and HFSEs like Nb and Ta (e.g., Zhang et al 2007;Peng et al 2007).…”

Zircon U/Pb dating and Hf-O isotopes of the Zhouan ultramafic intrusion in the northern margin of the Yangtze Block, SW China: Constraints on the nature of mantle source and timing of the supercontinent Rodinia breakup

“…The 650-630 Ma magmatism are also reported in many places, such as those 650-630 Ma mafic dykes in the northern margin of the Tarim Block [84] and those 650-630 Ma alkaline complexes in the southern margin of the Siberian craton [85]. These intrusions may characterize the last magmatism related to the breakup of the Rodinian supercontinent [86,87]. Therefore, we propose that the 635 Ma mafic-ultramafic intrusions and coeval bimodal volcanic lavas in the Suizao basin recorded the last magmatism related to the breakup of the Rodinian supercontinent in the northern margin of the Yangtze Block.…”

“…We therefore consider that the positive ε Hf (t) values of the zircons from the Zhouan intrusion are signature of an enriched mantle source. The rocks from the Zhouan intrusion have nearly constant initial 87 Sr/ 86 Sr (t) ratios (I Sr ) (0.7046-0.7055) and ε Nd (t) values (−4.4-1.1.) They plot in the field near the enriched mantle (EM1) source ( Figure 5(b); our unpublished data and Yan et al [16]).…”