The Origin of Paleokarst in the Huanglong Formation of the Eastern Sichuan Basin: Evidence from δ13C, δ18O and87Sr/86Sr

A new study reveals that the paleokarst in the Huanglong Formation of the Eastern Sichuan Basin originated from atmospheric freshwater, providing critical insights into ancient hydrological conditions. The research analyzed carbon (δ13C), oxygen (δ18O), and strontium (87Sr/86Sr) isotopes across four types of karst rocks—ranging from slightly to intensely corroded—and compared them with non-karstic rocks. Findings indicate that atmospheric freshwater, characterized by distinct isotopic signatures, was the primary driver of karst formation, with varying degrees of corrosion reflecting different fluid interactions. The study also highlights the role of diagenetic fluids in altering these isotopes, offering a geochemical framework to understand the temporal and spatial distribution of paleokarst development in this UNESCO World Heritage Site.

CHEN, H., ZHENG, R., WEN, H., LI, S., LI, S., ZHOU, G., & WEN, L. (2014). The Origin of Paleokarst in the Huanglong Formation of the Eastern Sichuan Basin: Evidence from δ¹³C, δ¹⁸O and⁸⁷Sr/⁸⁶Sr. Acta Geologica Sinica - English Edition, 88(6), 1852–1862. Portico. https://doi.org/10.1111/1755-6724.12351