Climate sequence and Sphinx-pyramid construction timeline. Great Sphinx and basin endured both water and wind erosions in different times Climate sequence: humid period first (water erosion), then arid period second (wind erosion) In remote past, Giza region was humid with much more rainfall; workers excavated catch basin at bottom of plateau

The Great Sphinx erosion debate continues: research by Robert Schoch proposes water weathering patterns on the monument, suggesting extensive erosion prior to 5000 B.C. when Egypt may have had more rainfall. However, a 2023 NYU study proposes wind erosion as a primary natural sculptor of the Sphinx's body before human carving. The two erosion hypotheses remain in contention, with Schoch's water weathering theory considered controversial and some scholars arguing a moat system could explain water patterns without requiring a wetter past. The Giza plateau's geological history and its connection to regional climate conditions continue to be debated.

Key Facts

  • Great Sphinx and basin endured both water and wind erosions in different times
  • Climate sequence: humid period first (water erosion), then arid period second (wind erosion)
  • In remote past, Giza region was humid with much more rainfall; workers excavated catch basin at bottom of plateau
  • Stone from basin used to build front structures as stormwater detention facilities
  • Limestone block left in center of basin functioned as flow control to manage water velocity/volume
  • When climate became extremely arid, limestone block was exposed and isolated, eroded to sphinx-shaped yardang over thousands of years
  • Later, wind erosion damaged bottom pyramid casings; maintenance team repaired with more durable granite and basalt
  • Methods and materials of adding new casings at different Giza structures are identical, signifying pyramids were contemporaries with Sphinx basin and temples
  • Sphinx basin with water erosion marks and pyramids likely created during same relatively humid era as part of giant industrial mining operation

Related site: Giza Necropolis — view location, images, and history on the Ancient Nerds map.

Source: Geological Evidence at Giza: The Sphinx Erosion Mystery by Curious Being