Ediacaran magmatism and rifting along the northern margin of the Tarim craton: Implications for the late Neoproterozoic Rodinia configuration and breakup

Abstract The Tarim craton in modern Central Asia was an important component of the supercontinent Rodinia Neoproterozoic, although its paleogeography during that era is still controversial. Here, we present new stratigraphic, geochemical, and geochronological data from Neoproterozoic sedimentary volcanic rock successions along northwestern margin discuss significance these our interpretations for tectonic evolution paleogeographic position within Rodinia. Lower Ediacaran sequence (Sugetbrak Formation) northwest includes terrestrial shallow-marine clastic rocks intercalated with two discrete basaltic lava flows near top. Upper conformably overlying consists mainly stromatolitic dolomite (Chigebrak Formation), representing a transgressive environment. Previous U-Pb zircon dating has constrained timing their eruption early (615 Ma). Detrital feldspar-quartz-sandstone unit situated between revealed oldest age 2517 ± 18 Ma youngest 612 6 Ma, majority grains (n = 42) dated at 891–754 (Tonian). A quartz-sandstone above upper flow 2724 15 607 8 missing group 891–800 Ma. These observations indicate: (1) major switch depositional setting (synrifting) to environment following unit; (2) abrupt disappearance source zircons sediments provenance post-615 (postrifting) sequence. have low SiO2 MgO but high total Fe2O3 TiO2 contents (2.34–3.19 wt%), analogous high-Ti basalts continental flood basalts. Their Ti/V ratios (65–88), Th/Nb (~0.1), TiO2/Yb (~1.1) are similar those ocean-island basalt (OIB). Combined Sm/Yb La/Sm Sr-Nd-Pb-Hf isotope values, infer magmas Sugetbrak were likely derived partial melting enriched mantle (EM I) transitional spinel-garnet lherzolite field. This petrogenetic result plume–influenced rift magmatism breakup Tianshan terrane, which attached northern until Period, (Tonian) synrift succession. As terrane broke away after ca. 615 Tonianaged no longer available depocenter postrift transition rifting drifting marked final Rodinia, global event possibly driven by plume activities coeval development Iapetus magmatic province Laurentia Ediacaran.