本文關(guān)鍵詞： 揚子西緣 新元古代冰川 列古六組 LA-ICP-MS 鋯石U-Pb年齡　出處：《礦物巖石》2017年01期 　論文類型：期刊論文

【摘要】：長期以來,川西地區(qū)列古六組一直被認(rèn)為與新元古代冰川晚冰期(Marinoan)地層南沱組相當(dāng),從而認(rèn)為揚子西緣缺失早冰期(Sturtian)沉積,但缺少可靠的年代學(xué)證據(jù)。針對川西列古六組底部凝灰質(zhì)雜礫巖鋯石LA-ICP-MS U-Pb定年結(jié)果表明,~(206)Pb/~(238)U年齡范圍為722 Ma~902 Ma,在~725 Ma,~780 Ma,~820 Ma和~850 Ma具有明顯的峰值。其中,最年輕一組~(206)Pb/~(238)U年齡加權(quán)平均值為724 Ma±12 Ma,代表列古六組底部雜礫巖的最大沉積時間。列古六組沉積序列特征以及華南Sturtian冰期啟動年齡分布范圍綜合分析可知,川西列古六組下段為早冰期沉積,可與長安組對比,而上段則為間冰期沉積,可與富祿組和大塘坡組對比。因此,揚子西緣存在早冰期(Sturtian)和間冰期沉積,不存在晚冰期(Marinoan)沉積。
[Abstract]:For a long time, the Liegu 6 formation in western Sichuan area has been considered to be equivalent to the Neoproterozoic late glacial Marinoanian formation of the Nantuo formation. It is concluded that the western margin of Yangtze lacks early glacial Sturtian) deposits. However, reliable geochronological evidence is lacking. The zircon LA-ICP-MS U-Pb dating results of the six groups of Liegu conglomerate in western Sichuan show that the zircon from the tuffaceous complex is of great significance. The age range is 722 Ma~902 / 238U and 725 Ma~902 / 780Ma. There are obvious peaks at 820 Ma and 850 Ma, among which the youngest group is 724 鹵12 Ma, the weighted average of the age is 724 Ma 鹵12 Ma. It represents the maximum sedimentary time of the six groups of Liegu complex, the characteristics of the sedimentary sequence of the six groups and the range of the onset age distribution of the Sturtian glacial age in South China. The lower member of the six member of Liegu formation in western Sichuan is an early glacial deposit, which can be compared with Changan formation, while the upper member is an interglacial deposit, which can be compared with that of Fulu formation and Datangpo formation. There are early glacial Sturtian) and interglacial deposits in the western margin of Yangtze, but no late glacial Marinoan) deposits.
【作者單位】： 中國地質(zhì)調(diào)查局成都地質(zhì)調(diào)查中心;國土資源部沉積盆地與油氣資源重點實驗室;成都理工大學(xué)沉積地質(zhì)研究院;中國地質(zhì)科學(xué)院研究生院;
【基金】：國家自然科學(xué)基金項目(41502114,41672112) 中國地質(zhì)調(diào)查局項目(12120114067901,1212011121105,121201010000150016)
【分類號】：P597.3;P588.212.5
【正文快照】： 1.中國地質(zhì)調(diào)查局成都地質(zhì)調(diào)查中心,四川成都610081;2.國土資源部沉積盆地與油氣資源重點實驗室,四川成都610081;3.成都理工大學(xué)沉積地質(zhì)研究院,四川成都610059;4.中國地質(zhì)科學(xué)院研究生院,北京p膒苝蘰，

本文編號：1460199