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• The Oulongbuluke Block records ca. 1.5–1.45 Ga and ca. 1.1 Ga magmatic and metamorphic events. • The Oulongbuluke Block was a response to the breakup of the Columbia supercontinent. • The Oulongbuluke Block was a response to the assembly of the Rodinia supercontinent. The Oulongbuluke Block, which is one of several ancient micro-continents on the southeast margin of Tarim in NW China, has been considered a nearly extinct fragment of the Tarim Craton. Here, zircon U-Pb, Lu-Hf isotope, petrologic and geochemical studies were carried out on the migmatites, grey felsic gneisses, mafic granulites and augen granitic gneisses from Wulan County on the eastern margin of the Oulongbuluke Block. Macroscopic and microscopic observations show that the felsic migmatite is mainly composed of plagioclase-rich leucosomes and melanosomes. The plagioclase-rich leucosomes with positive Eu and Sr anomalies occur as layers and veins, showing in situ partial melting features. Zircon U-Pb dating and Hf isotope analyses on the melanosome, grey felsic gneisses, mafic granulites and augen granitic gneisses from the Oulongbuluke Block yield three age populations at 1500–1496 Ma, 1454–1443 Ma and 1113–1104 Ma. The ca. 1.5 Ga magmatic zircon cores of the grey felsic gneiss and melanosome possess ε Hf (t) values between −3.5 and 3.9, with two-stage Hf model ages (T DMC) between 2.4 Ga and 2.0 Ga. The ca. 1.1 Ga zircons from samples of augen granitic gneiss have ε Hf (t) values of −5.2 to 0.5, and the corresponding T DMC values range from 2.2 to 1.9 Ga. Petrological, geochemical and geochronological data suggest that ca. 1.5 Ga magmatic protoliths of grey felsic gneisses were produced by dehydration melting in predominant lower crust setting and experienced metamorphism and anatexis at 1.45 Ga in a rift setting. The precursor magmas of augen granitic gneisses were derived from partial melting of mafic crustal sources in an active continental margin environment. Comparing the tectonothermal events recorded in the Oulongbuluke Block with those in other cratons, the Oulongbuluke Block, Tarim Craton and North China Craton have similar evolutionary histories before the late Mesoproterozoic, suggesting that they were linked together and involved in the assembly and break-up of the Columbia supercontinent. However, the South China Craton, Qilian Block, Oulongbuluke Block, North Qaidam and Tarim Craton were likely temporarily connected during the late Mesoproterozoic-early Neoproterozoic (1.1–0.9 Ga), which corresponded to the assembly of the Rodinia supercontinent. [ABSTRACT FROM AUTHOR]

• The metamafic rocks can be classified into high-Fe and low-Fe groups, and the former is similar to N-MORB and the latter is similar to E-MORB. • The high-Fe and low-Fe groups may have been derived from different parts of a mantle plume. • The Tarim Craton, North China Craton, and North Australia Craton may potentially dominated by the same superplume. In the Mesoproterozoic, there was an epic transition on Earth, the final breakup of the Columbia supercontinent. Understanding the dynamic mechanism responsible for the final breakup of Columbia supercontinent is crucial for establishing Earth's evolution that includes geology, environment and life. However, there is little research on what drove the breakup of the Columbia supercontinent. Here we focus on this issue by integrating new zircon U-Pb ages, Lu-Hf isotopes, and whole-rock geochemical data for metamafic rocks from the Oulongbuluke Block in the southeast of Tarim Craton. These data show that the protoliths of these metamafic rocks were emplaced at ca. 1.37–1.35 Ga and were divided into high-Fe and low-Fe groups. The high-Fe and low-Fe groups show geochemical character similar to normal mid-ocean ridge basalt (N-MORB) and enriched mid-ocean ridge basalt (E-MORB), respectively. The high-Fe group was formed by high degree (7%-9%) partial melting of spinel-phase lherzolite mantle source, whereas the low-Fe group was derived from low degree (5%-6%) partial melting of spinel-phase lherzolite mantle source. We propose that the high-Fe and low-Fe groups may have been derived from magmas from different parts of a mantle plume. The formation of the 1.37–1.35 Ga metamafic rocks in the Oulongbuluke Block may be related to the separation of the Tarim Craton into North and South Tarim cratons, which resulted in the opening of the initial Middle Tarim Ocean Basin. By comparison with the plume-induced Yanliao Rift of North China Craton and McArthur Basin of North Australia Craton, we present that these three cratons may potentially dominated by a superplume, forming circular rift zone and radiating dykes. This superplume triggered the continuous extension to most parts of Columbia and led to the final breakup of the Columbia supercontinent. [ABSTRACT FROM AUTHOR]

• The South Orogen underwent early post-collision during 1.90–1.85 Ga, followed by late post-collision during 1.80–1.73 Ga. • The North Orogen experienced early post-collision at 1.80–1.73 Ga and then entered the late post-collision at 1.67–1.60 Ga. • Finally, the South Orogen and North Orogen simultaneously entered the initial breakup stage during 1.55–1.47 Ga. The Tarim Craton located in the northwest of China, where the Paleo-Mesoproterozoic extensional magmatism related to the Columbia supercontinent is widely developed. However, the process and time of the extension and initial breakup of the Tarim Craton are still controversial during Paleo-Mesoproterozoic era. In this contribution, we present a systematic petrographic, geochemical, and zircon U-Pb-Hf investigation on Aketashitage granite dykes, Wulan granitic gneisses and Astingbulake metadiabases from the Tarim Craton. Results from our study indicate that the ca. 1.88–1.86 Ga Aketashitage granite dykes belong to I-type granites, which were probably derived from low degree partial melting of thickened Archean crust during early post-collisional setting. The ca. 1.55 Ga Wulan granitic gneisses also show the characteristics of I-type granites, which mainly came from partial melting of mafic lower crust with minor mantle-derived magma input during the rift setting. The ca. 1.55 Ga protoliths of Astingbulake metadiabases show affinity to ocean island basalts and/or continental flood basalts and were produced by partial melting of enriched continental lithospheric mantle under continental rifting setting. In conjunction with previous studies, it can be concluded that the Tarim Craton experienced episodic extension to initial breakup: the South Orogen underwent early post-collisional extension during ca. 1.90–1.85 Ga, followed by late post-collisional extension during ca. 1.80–1.73 Ga; the North Orogen experienced early post-collisional extension at ca. 1.80–1.73 Ga and then entered the late post-collisional extension at ca. 1.67–1.60 Ga; finally, the South Orogen and North Orogen simultaneously entered the initial breakup stage during ca. 1.55–1.47 Ga. Based on a comparison of the global Mesoproterozoic (ca. 1.58–1.45 Ga) magmatic activities as a response to the initial break up of the Columbia supercontinent, we suggest that the Tarim Craton (including the Oulongbuluke Block) and North China Craton were close to India, Australia, Yangtze, Siberia, Congo, São Francisco and West African. [ABSTRACT FROM AUTHOR]