摘要
根据遗迹相和沉积特征，将龙洞水组、大河口组和屯上组划分为８个层序，其中包括２个Ⅰ型、６个Ⅱ型层序，在此基础上，对缺失标准化石依据的中、下泥盆统界线提出了讨论。黔南独山地区的龙洞水组和大河口组为海平面逐渐下降、富氧环境的沉积，屯上组为海平面迅速上升、缺氧或贫氧环境的沉积，大河口组和屯上组之间存在一古风化壳层，是海平面下降至最低点的产物，并有地层缺失，为一较明显的自然界线，下、中泥盆统界线置于此界面更近于实际。产于舒家坪组的Ｅｕｒｙｓｐｉｒｉｆｅｒｐａｒａ－ｄｏｘｕｓｓｈｕｊｉａｐｉｎｇｅｎｓｉｓ腕足化石群不能作为下泥盆统的顶界。
According to the trace fossils and sedimentary characteristics, Longdoshui, Dahekou and Tunshang Formation can be divided to eight sequences of Devonian in the Dushan area, Guizhou,the sea level would be dropped and water body and depositional environments were aerobic during Longdongshui to Danhekou, and the sea level would be upward fastly and became a dysaerobic or even anaerobic environments during Tunshang. The boundary of Lower Middle Devonian may be drawn on between Danhekou and Tunshang Formations, where is an obvious nature boundary characteristiced by old karst and lack some strata, Euryspirifer paradoxus shujiapingensis from Shujiaping Formation may be in or below Polygnathus Serotinus Zone, upper Deronian.
出处
《矿物岩石》
CAS
CSCD
北大核心
1998年第2期40-46,共7页
Mineralogy and Petrology
关键词
遗迹化石
层序地层
中泥盆统
下泥盆统
地层界线
fossils sequence stratigraphy boundary of Lower Middle Devonian Dushan of Guizhou
