Development of Sulfuric Acid Speleogenetic Deposits within Cavernous Middle Eocene Beds: Inference on Hydrocarbon Gas Seepages, Giza Pyramids Plateau, Egypt

A groundbreaking study reveals that the paleokarst features of the Giza Pyramids plateau were shaped by a hypogene sulfuric acid karst system, driven by groundwater containing hydrogen sulfide (H2S), sulfuric acid (H2SO4), and carbonic acid (H2CO3). The research, conducted through field observations, microscopy, X-ray diffraction, and fluorescence analyses, identifies mineral deposits such as natroalunite, aluminum-phosphate-sulfate, hydrated halloysite, and Fe/Mn oxides within cavernous middle Eocene beds. These deposits suggest a multi-stage process involving the ascent of H2S gas from Cretaceous reservoirs, oxidation to H2SO4, descent of carbonic acid-rich solutions, and subsequent reactions with host rocks. The study also highlights the role of stratiform cavity formation in creating fractures filled with displacive fibrous satinspar gypsum, providing new insights into the geological history of this UNESCO World Heritage Site.

BADAWY, H. S. (2021). Development of Sulfuric Acid Speleogenetic Deposits within Cavernous Middle Eocene Beds: Inference on Hydrocarbon Gas Seepages, Giza Pyramids Plateau, Egypt. Acta Geologica Sinica - English Edition, 95(3), 946–961. Portico. https://doi.org/10.1111/1755-6724.14512