Early Cretaceous Climate Changes Recorded in Magnetic Susceptibility and Color Index Variations of the Lower Liupanshan Group, Central China

This study carried out comprehensive analysis on sedimentology, magnetic susceptibility (χ_lf) and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change information during the 129.14–122.98 Ma interval. Based on the results of the χ_lf and of the redness (a*), the section can be divided into two segments: (1) 129.14–126.3 Ma, with the lowest χ_lf values and strongly variable relatively high values of redness and (2) 126.3–122.98 Ma, with high χ_lf values and relatively low redness. Analysis of the lithology and facies as well as the magnetic minerals and their contents points to a detrital origin of the magnetic minerals and this allow us to interpret the relationship between magnetic susceptibility variations and climate changes. Our study shows that the climate was significantly dry and hot during the whole studied interval although the interval between 126.3 Ma and 122.98 was a little bit cooler with increased humidity.