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

Abstract

AbstractThis study carried out comprehensive analysis on sedimentology, magnetic susceptibility (χlf) 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 χlf and of the redness (a*), the section can be divided into two segments: (1) 129.14–126.3 Ma, with the lowest χlf values and strongly variable relatively high values of redness and (2) 126.3–122.98 Ma, with high χlf 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.