石油与天然气地质 ›› 1983, Vol. 4 ›› Issue (3): 246-253.doi: 10.11743/ogg19830302

• 论文 • 上一篇    下一篇

鄂尔多斯盆地东南缘的寒武系

张韦   

  1. 地质矿产部第十二普查勘探大队
  • 收稿日期:1982-09-13 出版日期:1983-09-25 发布日期:2012-01-16

CAMBRIAN SYSTEM IN THE SOUTHEAST MARGIN OF ORDOS BASIN

Zhang Wei   

  1. The 12th Brigade of Petroleum Prospecting and Exploration, Ministry of Geology and Mineral Resources
  • Received:1982-09-13 Online:1983-09-25 Published:2012-01-16

摘要:

鄂尔多斯盆地(以下简称盆地)东南缘,为山西离石至陕西韩城,即吕梁山脉中、南段到渭北东端禹门口、紫荆山一带(图1)。

Abstract:

Cambrian system are found at the southeast margin of Ordos basin,which distributed from Lishi in Shanxi province to Hancheng in Shaanxi province. From bottom to top,they are as follows:Lower Cambrian Mantou F. (∈1m);Middle Cambrian Maozhuang F. (∈2m);Xuzhuang F. (∈2x);Zhangxia F. (∈2z);Upper Cambrian Gushan F. (∈3g);Changshan F. (∈3c);Fengshan F. (∈3f)Various trilobites are found,totalling 23 families and 56 genera. Type section of the area is in Xiweikou of Hejin,Shanxi province.Discovery of Redlichia chinensis in 1964 in Hancheng proved not at all absence of Mantou sediments in this area. Take the Maozhuang F. as the beginning of the middle Cambrian,the strata are characterized by abundant Ptychopariidae. The Shabtungaspis aclis,among the 6 important genera,is the most widespread one.The Xuzhuang F. contains 4 fossil zones,such as Kochaspis hsuchuangensis,Sunaspis laevis,Porigraulos abrota and Honanaspis.The Zhangxia F. shows the climax of development of trilobites,which comprises 50% of the total amount of the genera found in Cambrian system in the area.The Gushan F. is considered as a marker bed for distinguishing the middle from the upper series,due to the stability in trilobite groups,lithology and thickness.Remarkably rare trilobites are found both in the Changshan and Fengshan Formations. Moreover,the top of the latter is characterized by Calvinella."Huoshan sandstones" to the south of lat. 36 N. correspond to the base of the Mantou F.,but to the north of it,most of them match the Maozhuang F. In Zhongyang region,they can be traced up to the base of the Xuzhuang F.,while they were completely missed along Sanchuan river.It is rational to place the boundary of the Cambrian and Ordovician in between earlier Ordovician dolomitic limestones with cherty bands (containing Aotiaspis cf. karaipsis) and Fengshan dolomitic limestones (containing Calvinella).