论文部分内容阅读
A SHRIMP U-Pb zircon geochronology study of the tuff at the bottom of the Lower Cambrian Niutitang Formation at Songlin,Zunyi,South China yielded a mean 206Pb/238U age of 518±5 Ma.It is significantly younger than the Re-Os ages of 537―542 Ma for the overlying polymetallic Ni-Mo-PGE-rich layer in the basal Niutitang Formation at Songlin,suggesting that the Re-Os ages might represent that of the original magma chamber for the Ni-Mo-PGE-rich layer rather than the formation age of the strata.The intra-basinal stratigraphic correlation also implies that the absolute age of the Chengjiang biota should be younger than 518±5 Ma.Our new result,together with the SHRIMP U-Pb zircon age for the K-bentonite in the Zhongyicun member of the Zhujiaqing Formation at the Meishucun section,Yunnan Province,provides a temporal constraint for the Lower Cambrian of the Yangtze Platform in South China.
A SHRIMP U-Pb zircon geochronology study of the tuff at the bottom of the Lower Cambrian Niutitang Formation at Songlin, Zunyi, South China yielded a mean 206 Pb / 238 U age of 518 ± 5 Ma.It is significantly younger than the Re-Os ages of 537-542 Ma for the overlying polymetallic Ni-Mo-PGE-rich layer in the basal Niutitang Formation at Songlin, suggesting that the Re-Os ages might represent that of the original magma chamber for the Ni-Mo-PGE-rich layer rather than the formation age of the strata. the intra-basinal stratigraphic correlation also implies that the absolute age of the Chengjiang biota should be younger than 518 ± 5 Ma.Our new result, together with the SHRIMP U-Pb zircon age for the K -bentonite in the Zhongyicun member of the Zhujiaqing Formation at the Meishucun section, Yunnan Province, provides a temporal constraint for the Lower Cambrian of the Yangtze Platform in South China.