神农架陡山沱组沉积特征及其对“鄂西海槽”的启示

华南埃迪卡拉系陡山沱组沉积古地理仍有争议，其中鄂西克拉通内盆地“鄂西海槽”的存在与展布问题是关键.对“鄂西海槽”分布关键位置的神农架地区陡山沱组开展了地层学和沉积学研究，结果显示:神农架东部地区陡山沱组的岩性组合与黄陵背斜北部樟村坪地区陡山沱组相似，发育鸟眼和球粒等沉积构造，指示了台地环境；神农架西部地区陡山沱组主要由砂岩、粉砂岩和泥岩组成，产出粒序和平行层理等组成的不完整鲍玛序列，指示斜坡或较深水环境.综合前人研究，指出“鄂西海槽”与“鄂中台地”的边界从神农架地区中部经黄陵背斜西北延伸到其东南，神农架东部和黄陵背斜东北部地区位于台地内，神农架西部和黄陵背斜西南部地区位于海槽内. 

Sedimentary Characteristics of Doushantuo Formation in Shennongjia Area:Implications for"West Hubei Trough"

Paleogeographic reconstruction of the Ediacaran Doushantuo Formation in South China is controversial, and one of the key problems is the existence and distribution of the "West Hubei Trough". In this paper it presents stratigraphic and sedimentological evidence of the Doushantuo Formation from the Shennongjia area (Hubei Province) for the existence of "West Hubei Trough" and its sedimentary facies in Shennongjia area. Lithological features of the Doushantuo Formation in the eastern Shennongjia area are similar to those in the Zhangcunping area, northern Huangling anticline near Three Gorges. Sedimentary structures such as "bird eyes" and peloids indicate that the Doushantuo Formation in the eastern Shennongjia area was deposited in a shallow platform environment. The Doushantuo Formation in the western Shennongjia area is mainly composed of interbedded sandstone, siltstone and mudstone. In addition, sedimentary structures, such as incomplete Bouma sequences containing normal graded bedding and parallel bedding, indicate a slope or relatively deeper water environment of the western Shennongjia area. In combination with previous studies, our results indicate that the boundary between the "West Hubei Trough" and the "Central Hubei Platform" extends from the middle Shennongjia area to the northwest of Huangling anticline area as well as to its southeast. The eastern Shennongjia and northeast Huangling anticline were both located in platform facies, whereas the western Shennongjia and southwest Huangling anticline were located in deeper water facies of the "West Hubei Trough".