摘要
近年来,作者对贺兰山区奥陶系进行了岩石地层及生物地层学的研究,取得了新的进展。确证该区寒武系与奥陶系为连续沉积,对奥陶系进行了合理划分和时代厘定,初步建立了11个化石带或生物组合。该区是华北地台西缘奥陶系发育最好、生物地层研究最清楚的地区。根据沉积物及生物特征,确认本区中奥陶统为大陆边缘斜坡相沉积,浊流特征颇为典型。是研究斜坡沉积作用及其相模式、古构造古地理演化及其含矿性的理想地区。
This paper deals with the Lithostratigraphy and Biostratigraphy of the Ordovician System in Helanshan area. The new advances have been made by authors, i. e., it is proved that the Cambrian and Ordovician strata are successive. The Ordovician strata has been divided resonably and revised in epoches inn this paper, therefore, 11 fossil zones or biological assemblages of Ordovician are set up in the area.The Middle Ordovician Yinchuan Formation 11 Protopanderodus insculptus zone
The Middle Ordovician Shanzigou Fm. 10 Nemagraptus-Dicellograptus assemblage zone
The Middle Ordovician Yingtaogou Fm. 9 Amplexograptus deceratus amplexograptoides zone 8 Cordylodus horridus-Periodon arcuatus assemblage zone
The Lower Ordovician Zhongliagzi Fm. 7 Tangshanodus tangshanensis zone 6 Aurilodus leptosomatus-Loxodus dissectus zone 5 Wutinoceras zone
The Lower Ordovician Qianzhongliangzi Fm. 4 Serratognathus-Bergstroemognathus assemblage zone
The Lower Ordovician Xialingnangou Fm. 3 Scolopodus opimus-Glyptoconus quadraplicatus zone 2 Rossodus mantouensis zone 1 Scolopodus primilivus zone
The Upper Cambrian Fengshan Fm. Cordylodus proavus zone
All of the data given above show that in the west margin of the North China platform, the Ordovician in Helanshan area was best developed and is most clearly studied.
According to the sedimentary and biological characters, the Authors consider that the middle Ordovician System in this area was deposited in the Continental margin with typical turbidite sedimentation. The area is the best place for the study of slope sedimentation and its facies model, palaeotectonics, palaeogeography and ore-bearing potentiality.
出处
《现代地质》
CAS
CSCD
1991年第2期119-137,共19页
Geoscience
关键词
化石带
生物组合
奥陶纪
贺兰山
: fossil zone, biological assemblages, Ordovician, Helanshan, Turbidite de-position
