Fortune telling in taoyuan village _ Fortune telling in Taoyuan

Since the Early Cretaceous, the basins on the north and south sides of the Dabie orogenic belt have been volcanic in varying degrees, especially in the eastern part of the Dabie orogenic belt (Anhui). There are three volcanic basins in the North Huaiyang structure: Jinzhai, Huoshan and Xiaotian. There are Chuzhou, Luzong and Huaining volcanic basins, Ningwu and Fanchang volcanic basins in the south and north of the Yangtze block. Recently, Zhou Cunting et al. (1998) and Qian Cunchao et al. (1998) discovered the existence of Mesozoic (136 ~ 129 Ma, Liu Dunyi et al., 2002) volcanic rocks and volcanic institutions in the Dabie complex in the hinterland of the Dabie orogenic belt. Mesozoic volcanic rocks in this area are divided into Maotanchang Formation, Baidafan Formation, Xianghongdian Formation and Xiaotian Formation from bottom to top, belonging to Cretaceous.

The volcanic rocks of Maotanchang Formation are a continuous magmatic evolution sequence from neutral to moderately acidic to acidic from bottom to top. The lower part is andesite-trachyandesite assemblage, which consists of eruption → overflow facies → eruption facies andesite, andesite breccia, tuff mixed with sedimentary pyroclastic rock and trachyandesite ignimbrite. The upper part is dacite-rhyolite assemblage, which mainly belongs to calc-alkaline series, evolving to weakly alkaline from erupting dacite tuff, condensed breccia tuff → erupting dacite → sedimentary pyroclastic rock to erupting rhyolite tuff, breccia tuff → erupting rhyolite tuff. Taoyuanzhai volcanic rock belongs to the dacite-dacite assemblage, which is composed of dacite and dacite granulite tuffaceous lava and microcrystalline tuffaceous lava, which is equivalent to the lower rock assemblage of Maotanchang cycle.

Baidafan Formation is mainly composed of dacite, rhyolite and trachyte volcanic rocks, which are only distributed in Beihuaiyang volcanic basin, and its lower part is in parallel unconformity contact with Maotanchang cyclic volcanic rocks.

Xianghongdian Formation is a set of alkaline volcanic rock assemblages, in which alkaline basalt and pseudoleucite-pyroclastic sedimentary rocks are gathered in the early explosive phase, and pseudoleucite coarse tuff and tuff lava-sedimentary pyroclastic rocks are contained in the late explosive (or overflow)-sedimentary facies, belonging to alkaline series.

The lower part of Xiaotian Formation is basalt-andesite-rough andesite assemblage, which consists of eruptive basalt, andesite-eruptive rough andesite, eruptive sedimentary shale and marl. The upper part is trachyte assemblage, which is composed of explosive trachyte volcanic breccia (aggregate), lava overflow trachyte ignimbrite, intrusive trachyte porphyry and trachyte, belonging to weakly alkaline or alkali-calcium series.

In the volcanic basins such as Luzong and Ningwu in the south of Dabie Mountain, Longwangshan Formation, Dawangshan Formation and Shuangmiao Formation are from bottom to top, which are equivalent to Maotanchang Formation, Baidafan Formation and Xianghongdian Formation respectively. According to the division of Chen Piji (200 1), their ages are all Cretaceous. Longwangshan Formation is composed of coarse andesite and pyroclastic rock mixed with lava. The lower part of Dawangshan Formation is pyroclastic rock and the upper part is rough andesite volcanic rock. The bottom of Shuangmiao Formation is mudstone and conglomerate, and there are variegated tuff breccia, breccia-containing coarse basalt and coarse basalt on it. Pukou Formation, equivalent to Xiaotian Formation, is mainly composed of a set of purplish red clastic rock series.