The mystery of The Great Sphinx of Giza has puzzled Egyptologists for centuries.

Experts remain split over when the colossal limestone guardian, stretching 240ft in length and rising 66ft high, was built.

Mainstream Egyptology dates it back to Pharaoh Khafre’s reign – known as the Old Kingdom – 4,500 years ago, around 2500 BCE.

But now a renowned American geologist has weighed in, suggesting it might be much, much older than previously thought.

Dr Robert Schoch, a Yale-trained academic, told the Daily Mail the towering structure could actually be as old as 10,000 BCE.

He argues that the Sphinx and its eroded enclosure exhibit evidence of significant rainfall, which contradicts the arid climate the Sahara has experienced for the past 5,000 years.

He said: ‘It’s basically Geology 101, the Sphinx enclosure shows a rolling, undulating profile with deep vertical fissures at its base.

‘Such erosion can only result from water coming from above, precipitation and flash floods flowing down from the plateau into the enclosure.’

The Great Sphinx is a massive limestone sculpture depicting a mythical entity with a lion’s body and a human head, situated on the Giza Plateau in Egypt. Conventional Egyptologists attribute its creation to the reign of Pharaoh Khafre, approximately 4,500 years ago.

Dr. Schoch associates the Sphinx’s erosion with a catastrophic event occurring around 9700 BCE, when he suggests that a powerful solar eruption concluded the Ice Age, resulting in global flooding.

But he didn’t always think that way.

In 1990, he joined independent Egyptologist John Anthony West on a trip to the site, which sits besides the pyramids of Khufu and Khafre.

There, he planned to debunk West’s theories that the Sphinx is much older than previously believed.

‘I thought that I was going to basically tell him that he was all wrong,’ Dr Schoch said.

‘That there was a simple explanation for what he was seeing, that the weathering and erosion he was attributing to water was not accurate.’

The rounded contours and deep vertical cracks Schoch found in the Mokattam Formation limestone surrounding the Great Sphinx

Instead, ‘within 90 seconds’ of inspecting the site, he said that he was convinced otherwise.

Now, he believes the cataclysmic event wiped out a forgotten civilization – one that first constructed the Sphinx.

He said: ‘The ancient dynastic Egyptians talked about an earlier cycle of civilization that went back thousands of years.’

This primordial epoch – dubbed Zep Tepi or ‘First Time’ – is mentioned in ancient Egyptian texts and dates between 2400 and 2300 BCE.

The forgotten civilization is also found in the Turin King List, a papyrus cataloging mythical pre-dynastic rulers that dates back to 1279 BCE, and describes a golden age when ‘gods walked among men.’

Dr Schoch’s original position was one of many mainstream scholars: the erosion was caused by wind or moving water that would have come from the Nile river flooding.

But now, he cites two points that made him reconsider his own position while on that trip to Egypt.

Dr Robert Schoch, a Yale-trained geologist, has been studying the Sphinx for more than 30 years, concluding it was built more than 12,000 years ago

First, he said: ‘The Sphinx’s erosion and weathering did not match the Sahara’s arid conditions. They point to a much earlier, wetter climate.’

The second was the enclosure itself. It was a quarry-like depression carved from the Mokattam Formation limestone, which exhibited rounded contours and deep vertical cracks.

Both characteristics are hallmarks of precipitation, he said, not of horizontal abrasion.

Schoch explained that the flooding Nile ‘would give a different type of erosional profile’ than the one seen on the structure today.

His findings align more closely with the African Humid Period, between 14,500 and 5,000 years ago (around 12,000 to 3000 BCE).

At that time, the Sahara was a lush grassland nourished by monsoons, as shown by pollen found deep in the sediment of Chad’s Lake Yoa and traces of ancient riverbeds throughout the region.

He believes the evidence lies in the erosion along the base, which he said was from excessive amounts of water that stemmed from a cataclysmic event that caused the ice age more than 11,000 years ago

This led Dr Schoch to believe the civilization under Khafre’s reign actually repaired the Sphinx instead of building it.

He noted the Sphinx’s head is currently much smaller than its body, suggesting the structure was re-carved at some point.

‘The original head would have been very weathered and eroded, as is the body. And in dynastic times, circa 2500 BCE, the body of the Sphinx was heavily repaired by the dynastic Egyptians.

‘I believe this ancient structure was considered highly sacred and important. 

Dr Robert Schoch believes that the civilization during Khafre’s reign repaired the Sphinx, noting that the head is much smaller than the body

‘Evidence of repairs is still visible on the Sphinx’s body, with blocks dating from the Old Kingdom, New Kingdom, Greco-Roman periods and even more recent times. 

‘The oldest repair blocks date to the Old Kingdom… which makes absolutely no sense [for the supposed 2500 BCE construction date].’

He explained that if the mainstream dating of the Sphinx is accurate, that would mean ancient Egyptians conducted repairs for even the smallest amount of erosion on the massive monument. Something he said was unlikely. 

While Schoch’s theory remains controversial, it has reignited interest in the Sphinx’s true origins.

Mainstream Egyptologists, including Dr Zahi Hawass and Mark Lehner, continue to argue that the monument dates only as far back as Pharaoh Khafre’s reign. 

They contend that observed erosion can be explained by salt exfoliation and other natural processes, rather than rainfall.

Yet the debate underscores how much remains unknown about the Sphinx, its construction and the environment of ancient Egypt.

If Schoch’s dating is correct, it could suggest that an advanced civilization existed thousands of years before Egypt’s known pharaohs, potentially reshaping our understanding of human history.