Study On Lithofacies Palogeography Of Ordovician In Luxi Block

Luxi block locates in the west of the Tanlu faulted zone in Shandong provience with a high research of Ordovician strata. There are a lot of fossils of the palaeophyte and profect outcrops.However, it has not yet received enough research of the lithofacies palaeogeography. Because the Ordovician of Luxi is mainly the carbonate platform, it can be the important part to the research of the marine strata.A lot of study about Ordovician in Luxi block has been preceded since the last century. In this paper, the latest framework and the experience of chronostratigraphic classification has been used to divide the Ordovician strata into five stairs:Tremadocian, Floian, Dapingian, Darriwilian and Sandbian. Tremadocian equals to "b"paragraph of the Sanshanzi formation, which is mainly the dolomite; Floian is equal to the a paragraph of Sanshanzi formation and the lowest dolomite of Majiagou formation, Liangjiashan and Donghuangshan, which are both the dolomite; Dapingian is Beianzhuang and is mainly limestone; Darriwillian equals to the Tuyu and Wuyangshan paragraphs, which is the second cycle of the limestone and dolomite; and Sandbian is equal to the uppermost layer, which includes the Gezhuang paragraph, Badou paragraph and Xinwen paragraph. While Gezhuang paragraph is mainly dolomite, Badou paragraph is mainly limestone and Xinwen is dolomite, limestone and sandstone.The important results and conclusion:1. Do the chronostratigraphic classification based on the criterion of Chronostratigraphy subdivision approved by the ICS in 2007;2. The sedimentary facies includes three types:evaporate platform, restricted platform and open platform.3. Do the chronostratigraphic classification using the method of predominant facies;4. Floian and Sandbian are mainly evaporate platform, the open platform is the most developed facies in Dapingian, while the restricted platform can develop in every period.