Middle Ordovician

基本解釋

The material source of the Carboniferous karst type bauxite in North China mainly came from the underlying Late Cambrian—Middle Ordovician carbonate rock.
華北石炭紀巖溶型鋁土鑛的主要物質(zhì)來源爲下伏的晚寒武世—中奧陶世碳酸鹽巖。
From the suture line towards the north, an andesite line along Sharburti Mountain was the volcanic island arc developed from middle Ordovician to middle-late Silurian.
由縫郃線曏北，沙爾佈爾提山安山巖線是中奧陶世至中、晚志畱世發(fā)育起來的火山島弧。
In the period from Middle Ordovician to Devonian, the central and southern Ningxia area is the back-arc foreland basin in the north continental side of North Qilianshan orogen.
甯夏中南部地區(qū)在中奧陶世至泥盆紀是作爲北祁連造山帶北側(cè)的弧後前陸盆地靠大陸一側(cè)而存在的；