扬子陆块北缘六冲坪金矿方解石Sm-Nd等时线年龄及其地质意义

Sm-Nd Dating of Calcite in Liuchongping Gold Deposit in Northern Margin of Yangtze Block and Its Geological Significance

湖北省保康县六冲坪金矿点为鄂西黄陵背斜周缘沉积盖层中首次发现的微细浸染型金矿,对黄陵地区新类型金矿找矿突破具有重要指导意义。Sm-Nd同位素定年结果显示,成矿期6件方解石样品的^(147)Sm/^(144)Nd值介于0.0924~0.1336,^(143)Nd/^(144)Nd值介于0.511733~0.511840,Sm-Nd等时线年龄为(397±11)Ma,表明六冲坪金矿点形成于早—中泥盆世,是加里东晚期伸展背景下流体运移的产物,即黄陵背斜北缘可能存在一套加里东中—晚期区域性中低温热液成矿系列。

Liuchongping gold deposit,located in Baokang County,Hubei Province,is micro-disseminated gold deposit discovered for the first time in sedimentary cover around Huangling anticline in western Hubei Province.It has important guiding significance for the prospecting breakthrough of new types of gold deposits in Huangling area.The Sm-Nd isotopic dating results show that the ^(147)Sm/^(144)Nd of the six calcite samples vary from 0.0924 to 0.1336,and the ^(147)Sm/^(144)Nd values vary from 0.511733 to 0.511840.The Sm-Nd isochron age is(397±11)Ma,indicating that the Liuchongping gold deposit was formed in the Early-Middle Devonian,and is closely related to the Caledonian movement.It is the product of fluid migration under the background of the late Caledonian extension,suggesting that there may be a set of regional meso-Late Caledonian hydrothermal mineralization series in the northern margin of the Huangling anticline.