mal>The SHRIMP U-Pb ages for zircons in welded tuff from Wangchang Formation in Dongchuang Area, Yunan Province, are reported in this paper,and the 207Pb/206Pb age of the point of intersection between discordant and concordia curves for zircons with automorphic and zonal tecture in P13 are (2317±13) Ma(n=13, MSWD=3.3), and weighted average age is (2299±14) Ma (n=13, MSWD=5.9), implying that the sedimentary age of Wangchang Formation is early to mid Paleoproterozoic. The sedimentary age of underlying four formations in Dongchuang Area almost are ten billion years older than the Kunyang Group in central mas-microsoft-com:office:smarttags" />
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