Geochemical Characteristics and Paleoclimate Significance of the Upper Cretaceous Continental Red Beds in the Danxia Basin, Northern Guangdong Province

Key words: 
• Upper Cretaceous /
• Danxia Basin /
• continental red beds /
• geochemistry /
• paleoclimate

Abstract: [Objective] The Danxia strata, a representative of Cretaceous continental red beds, offers key insights into red bed sedimentation and Cretaceous geological events through its climate signals. [Methods] This study examines fine-grained clastic rocks from the second and fourth members of the Changba Formation and the Jinshiyan Member of the Danxia Formation in the Upper Cretaceous Danxia Basin. Sedimentology and elemental geochemistry etc. were used to explore the sedimentary environment and paleoclimate significance during key Late Cretaceous stages (Cenomanian, Turonian, Campanian). [Results and Discussions] The results indicate that the fine-grained clastic rocks of these formations were deposited during a warm and humid climate phase, with suboxic to oxic water conditions. The water bodies were predominantly brackish, while localized high-salinity brackish and low oxygen environments (e.g., the fourth member of the Changba Formation) were associated with lake shrinkage and climatic aridification. Water depth variations exhibited trends of initial contraction followed by expansion, gradual contraction, and initial expansion followed by contraction, which align with the changes in sedimentary facies and environment. [Conclusions] The Upper Cretaceous terrestrial sedimentary records of the Danxia Basin illustrate the climatic evolution of intermontane basins, shaped by global climate patterns of the Late Cretaceous, as well as by significant influences from local topographic and geomorphic features.