Shuangfengling Formation in Jiangxi and Its Geological Age

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