江西双峰岭组及其地质时代

Shuangfengling Formation in Jiangxi and Its Geological Age

分析了江西中生代晚期火山岩系岩石地层单位划分的现状和存在的主要问题,提出以盛源盆地双峰岭剖面为层型剖面建立的双峰岭组代表武夷群下部的岩石地层单位。双峰岭剖面层序清楚、出露完好,双峰岭组以沉积岩为主夹火山岩,属沉积喷发相,代表火山活动初始期的产物;双峰岭组与上覆鹅湖岭组火山岩的界线为岩性岩相界面,在区域上便于识别,符合岩石地层单位划分的基本要求;双峰岭组流纹岩SHRIMP锆石U-Pb年龄为(134.3±1.6)Ma,不仅指示双峰岭组的地质时代属早白垩世早期,而且火山岩系与江西其它盆地的武夷群属同期火山活动的产物。

This paper analyzes the stratigraphic unit classification and some major existing problems of volcanic rock series in Late Mesozoic in Jiangxi, and presents that the established Shuangfengling Formation is based on stratotype section of Shuangfengling section at Shengyuan basin, representing the stratigraphic unit of Lower Wuyi Group. Shuangfengling section is well-outcropped, and has a clear stratigraphic sequence. Shuangfengling Formation is mainly sedimentary rocks interlarding with volcanic rocks, belonging to sedimentary eruption facies, and is the product of initial volcanic activities. The boundary of Shuangfengling Formation and volcanic rocks of its upper E＇ huling Formation is a interface of lithology and lithofacies, which is convenient to be distinguished regionally, conforming to the basic requirements of stratigraphic unit classification. The SHRIMP zircon U-Pb age of rhyolite in Shuangfengling Formation is （134.3 ±1.6） Ma, indicating not only that the geological age of Shuangfengling Formation belongs to early stage of Early Cretaceous, but its volcanic rock series, together with Wuyi Group at other basins in Jiangxi, are the product of volcanic activities in the same period