Paleoclimate Characteristics of the Middle Jurassic Xintiangou Stage in Yunyang Area, Northeast Sichuan Basin, China.

Two sections of the Xintiangou Formation were examined in the Yunyang area, Northeastern Sichuan Basin, China. One of them was systematically sampled from bottom to top. Palynology and geochemistry analyses were performed on 20 samples, and Paleoclimatic indicators were extracted. The sporopollen assemblage indicates arid and hot paleoclimate as a whole, and the geochemical index shows hot and humid paleoclimate. Combined with the analysis of sedimentary characteristics, it shows that the sedimentary period of the Xintiangou Formation in the study area is characterized by arid and hot paleoclimate as a whole, and there were fluctuations of relative moist and arid. The humid climate recorded by geochemical indicators may be the illusion that the unconsolidated sediments transported to the shore shallow lake zone experienced strong weathering. When studying the palaeoclimate characteristics of continental basins, it is necessary to analyze all kinds of palaeoclimate proxy indexes in combination with sedimentary facies, and there may be a deviation in using a single palaeoclimate proxy index to invert the palaeoclimate of continental basins. [ABSTRACT FROM AUTHOR]