Ordovician reefs奥陶系生物礁
Ordovician reservoir奥陶系储层;奥陶系油藏
ordovician chronostratigraphy奥陶纪年代地层学研究
Ordovician crudes奥陶纪石油
ordovician reef奥陶系生物礁
ordovician trilobite奥陶纪三叶虫
Ordovician oils奥陶系原油
ordovician water奥灰水
palaeozoic ordovician古生界奥陶系
The strata in upper Sinian, late Proterozoic Eras and cambine system, Ordovician, Silurian ,early palaeozoic and Devonian ,late palaeozoic outcrop in In this area. The main strata are Sedimentary superficial metamorphic fine Clastic Rock with carbonate rocks .
区内主要出露有早古生代寒武系、奥陶系、志留系及晚古生代泥盆系,发育一套浅变质细碎屑岩与碳酸盐岩沉积建造。
Mid-Ordovician limestone may also provide smallamounts of aluminum.
故认为,铝土矿的物源主要来自前寒武纪变质岩及花岗岩,奥陶纪石灰岩可能提供少量铝质。
参考来源 - 华北式(G层)铝土矿中的锆石标型研究ADJ（形容词） of, denoting, or formed in the second period of the Palaeozoic era, between the Cambrian and Silurian periods, which lasted for 45000000 years during which marine invertebrates flourished (古生代第二期)奥陶纪的; 属于(古生代第二期)奥陶纪的
N（名词） the Ordovician period or rock system 奥陶纪时期; 奥陶纪岩石系统