Geologist Renewed Claims That Great Sphinx May Precede Dynastic Egypt by Millennia

A Yale-trained geologist has reignited a long-running debate over the age of the Great Sphinx of Giza, asserting that patterns of weathering on the monument and its enclosure are more consistent with prolonged rainfall than with the arid conditions of the past 5,000 years. Robert Schoch said in recent interviews that the erosion could imply the monument, traditionally dated to the reign of Pharaoh Khafre around 2500 BCE, may date to the end of the last Ice Age — potentially to 10,000 BCE or earlier.

The Great Sphinx, a limestone statue with a lion's body and human head on the Giza Plateau, measures roughly 240 feet long and 66 feet high. Mainstream Egyptologists place its construction in the Old Kingdom during Khafre's reign and cite archaeological context within the pyramid complex. Schoch, who has studied the site for more than three decades, argues that the character of the weathering in the Mokattam Formation limestone that forms the Sphinx enclosure — rounded contours and deep vertical fissures — is diagnostic of precipitation-driven erosion rather than wind-blown sand or flooding from the Nile.

Schoch first visited the Sphinx in 1990 with independent Egyptologist John Anthony West; he has said that he expected to refute West's age hypothesis but that a brief inspection convinced him otherwise. Schoch points to rounded, undulating profiles and vertical cracking at the base of the enclosure — features he describes as “Geology 101” evidence of sustained rainfall and runoff — and distinguishes that pattern from the erosional signatures he associates with Nile inundation or salt-driven exfoliation.

He places the suggested timing of such wetter conditions within the broader climatic context of the African Humid Period, when parts of the present-day Sahara supported lakes and river systems fed by monsoons. Paleoclimate studies, including pollen records from Lake Yoa in Chad and geomorphological traces of ancient riverbeds, indicate that much of North Africa experienced substantially more rainfall between roughly 14,500 and 5,000 years ago. Schoch has also linked the erosion to a proposed cataclysm around 9,700 BCE, a hypothesis he and others have advanced to account for abrupt climatic change at the close of the last glacial interval; that link remains controversial.

Schoch argues that dynastic Egyptians repaired — rather than originally carved — the Sphinx, citing the disproportionate size of the head relative to the body and visible repair blocks from multiple historical periods. He notes the presence of masonry dating to the Old Kingdom, later New Kingdom interventions, and repairs in Greco-Roman times, and contends that the stonework indicates maintenance of an already ancient monument rather than initial construction circa 2500 BCE.

Mainstream Egyptologists, including former antiquities officials and field archaeologists, continue to date the Sphinx to Khafre's reign and dispute Schoch's interpretation of the erosional features. They argue that observed surface degradation can be accounted for by processes such as salt crystallization and exfoliation, thermal stress, and long-term exposure to wind-blown sand, combined with phases of repair documented in the stratigraphic and archaeological record. Those scholars also emphasize the archaeological association of the Sphinx with Khafre's pyramid complex and the lack, so far, of unambiguous datable cultural material at the foundation level that would compel a radically earlier construction date.

The debate over the Sphinx's age blends geological analysis with archaeological context and raises methodological questions about how to date large stone monuments that have undergone multiple episodes of weathering and repair. Schoch's geological argument focuses on geomorphology and comparative erosion patterns, while critics call for broader integration of stratigraphy, material sourcing, and secure archaeological dating methods.

If Schoch's interpretation were supported by additional multidisciplinary evidence, it would imply construction in a radically earlier climatic regime and could prompt reconsideration of human activity and monument-building capabilities in northeastern Africa before the rise of dynastic Egypt. Proponents of mainstream chronology caution that extraordinary revisions require equally strong, cross-disciplinary evidence.

The exchange highlights ongoing scientific disagreements about the Sphinx and the environment of ancient Egypt. Researchers on both sides say further fieldwork, including careful stratigraphic study, sediment analysis, and application of geochronological techniques, would be needed to resolve competing interpretations. For now, the Sphinx remains a focal point where geology, archaeology and climatology intersect in a debate over the monument's origins and the region's prehistoric environment.