The typical glacial-marine sedimentation has been recorded from core NP93-2 in the Prydz Bay, Antarctica. The sedimentation processes, sedimentary environment and paleoclimate variations since 12937 a B. P. have been ...The typical glacial-marine sedimentation has been recorded from core NP93-2 in the Prydz Bay, Antarctica. The sedimentation processes, sedimentary environment and paleoclimate variations since 12937 a B. P. have been discussed, based on grain size, mineral composition and micropaleontological data, etc.. The climate variation occurred at 10 ha, which expressed that there were increased inputs of terrigenous clastics. The climate change once again but temporarily took place at late Holocene.展开更多
The reported new U-Pb age by sensitive high-resolution ion microprobe (SHRIMP Ⅱ) on zircon was obtained from a tuff sample at the basal Doushantuo Formation in the Jiuqunao section, which situated at the western limb...The reported new U-Pb age by sensitive high-resolution ion microprobe (SHRIMP Ⅱ) on zircon was obtained from a tuff sample at the basal Doushantuo Formation in the Jiuqunao section, which situated at the western limb of the Huangling anticline in the Yangtze Gorges in Zigui, Hubei, South China. Eighteen spots of zircons were analyzed and they form two clusters: one includes three spots, with an inherited age of 784+ 15 Ma (MSWD=0.05); the other consists of 15 spots and gives a weighted mean ^206pb/^238U age of 628.3±5.8 Ma (MSWD=0.86). It is the first SHRIMP U-Pb zircon age obtained nearly the base of the Doushantuo Formation of Ediacaran and represents a maximum age of the Doushantuo Formation It also forms an age constraint on the upper limit age of the Nantuo (Marinoantype) glaciation.展开更多
文摘The typical glacial-marine sedimentation has been recorded from core NP93-2 in the Prydz Bay, Antarctica. The sedimentation processes, sedimentary environment and paleoclimate variations since 12937 a B. P. have been discussed, based on grain size, mineral composition and micropaleontological data, etc.. The climate variation occurred at 10 ha, which expressed that there were increased inputs of terrigenous clastics. The climate change once again but temporarily took place at late Holocene.
文摘The reported new U-Pb age by sensitive high-resolution ion microprobe (SHRIMP Ⅱ) on zircon was obtained from a tuff sample at the basal Doushantuo Formation in the Jiuqunao section, which situated at the western limb of the Huangling anticline in the Yangtze Gorges in Zigui, Hubei, South China. Eighteen spots of zircons were analyzed and they form two clusters: one includes three spots, with an inherited age of 784+ 15 Ma (MSWD=0.05); the other consists of 15 spots and gives a weighted mean ^206pb/^238U age of 628.3±5.8 Ma (MSWD=0.86). It is the first SHRIMP U-Pb zircon age obtained nearly the base of the Doushantuo Formation of Ediacaran and represents a maximum age of the Doushantuo Formation It also forms an age constraint on the upper limit age of the Nantuo (Marinoantype) glaciation.
