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Marble is associated with ultrahigh pressure eclogite in the Dabie Mountains, EastChina. U-Pb isotope data for the marble define a 238U-206Pb isochron age of 435± 45 Ma withan initial 206Pb/204Pb value of 18. 075±0.006. The age 0f ~ 435 Ma is interpreted to represent the time of limestone diagenesis rather than the time of metamorphic resetting accompa-nied by the formation of the ultrahigh pressure eclogites at Triassic. The paleontologic andstratigraphic studies also favor a local excursion in the carbon isotopic composition of the latestOrdovician water within a sedimentary basin between the Sino-Korean and Yangtze cratons.Because the latest ordovician limestone was involved in the eclogite formation, the continentalcollision between the Yangtze and Sino-Korean plates would postdate Ordovician.
Marble is associated with ultrahigh pressure eclogite in the Dabie Mountains, East China. U-Pb isotope data for the marble define a 238U-206Pb isochron age of 435 ± 45 Ma withan initial 206Pb / 204Pb value of 18. 075 ± 0.006. The age 0f ~ 435 Ma is interpreted to represent the time of limestone diagenesis rather than the time of metamorphic resetting accompa-nied by the formation of the ultrahigh pressure eclogites at Triassic. The paleontologic andstratigraphic studies also favor a local excursion in the carbon isotopic composition of the latest Odovician water within a sedimentary basin between the Sino-Korean and Yangtze cratons.Because the latest ordovician limestone was involved in the eclogite formation, the continentalcollision between the Yangtze and Sino-Korean plates would postdate Ordovician.