The Glacial Striations Beneath the Stonehenge Avenue: A Hidden Tale of Earth's Ice Age Past and the Mesolithic Foundation of the Sacred Stonehenge Landscape.

When we think of Stonehenge, what usually comes to mind is its iconic stone circle, shrouded in mystery and speculation about its purpose—be it astronomical, ceremonial, or something else entirely. However, beneath the surface of this ancient monument lies a fascinating geological feature that tells a story of an even more ancient event: the presence of glacial striations beneath Stonehenge Avenue.

Though often overlooked in favour of the greater monument’s cultural significance, these glacial markings hint at the Earth's icy past and reveal a dynamic chapter of our planet's natural history and arguably the foundational natural monument that originally marked out the Stonehenge area as sacred.

What Are Glacial Striations?

Glacial striations are long, linear grooves or scratches that are etched into the bedrock by the abrasive action of a glacier as it moves across the landscape. These markings form when rocks and debris embedded in the glacier’s base act like sandpaper, carving deep lines into the underlying ground. The direction of these striations provides clues about the movement of the ancient ice flow, helping geologists trace the paths of glaciers that once blanketed large parts of the Earth during the Ice Age that ended about 12,000 years ago.

The discovery of glacial striations beneath Stonehenge Avenue is significant because it provides evidence that glaciers once passed over this landscape, possibly influencing the positioning and topography of the site.

Stonehenge Avenue: A Path Through Time

The Stonehenge Avenue, is a ceremonial path thought to have been constructed around 2500 BCE, stretching about 1.5 miles (2.4 kilometres) from the henge monument to the River Avon. This avenue was likely an important processional route, connecting Stonehenge with the surrounding landscape and rivers, which were critical to the ancient people who built and used the monument. Interestingly, the route of Stonehenge Avenue follows a natural depression in the landscape, leading researchers to speculate that this geological feature was shaped long before humans began modifying the site. This is where glacial striations come into the story.

The Ice Age Influence on Stonehenge's Landscape.

During the last Ice Age glaciers covered much of northern Europe. Salisbury Plain, where Stonehenge is located, was just south of the main glacial boundary, the effects of ice sheets were likely to have extended into the region.

The presence of glacial striations beneath Stonehenge Avenue suggests that glaciers passed through or near this area, potentially shaping the terrain long before human hands began constructing the monument. The depressions and furrows left by glacial activity could have influenced where the builders chose to lay down the Avenue, following the natural contours of a landscape already moulded by the forces of ice. In fact, some researchers have speculated that the transport of Stonehenge’s iconic bluestones, which are believed to have been sourced from the Preseli Hills in Wales, might have been aided by glacial action. These stones, weighing  several tons each, were transported over 150 miles, and while human ingenuity is often credited with the feat, it’s possible that glaciers helped move these stones across long distances, depositing them closer to the Stonehenge site, making their transport easier for Neolithic builders.

Understanding the Striations: A Window into Prehistoric Climate.

The discovery of glacial striations beneath the Stonehenge Avenue (see Parker Pearson, M. (2023). Stonehenge: Exploring the Greatest Stone Age Mystery) not only adds depth to our understanding of the monument’s construction but also provides valuable insight into prehistoric climate conditions. It serves as a reminder that the site we now associate with ancient rituals and human ingenuity was once a landscape shaped by the slow, grinding forces of nature over millennia. These striations reveal that the Salisbury Plain, now a relatively temperate region, was once a harsh, icy environment where glaciers carved out features that we still see today. The scratches in the bedrock are a silent testament to the vast changes in climate and geography that have occurred over thousands of years, even before human beings left their mark on the land.

The Magical Landscape.

We know that Stonehenge is a centre of sacred monumentality, and an astronomical function is clear from its major orientation, the alignment to the Summer and Winter solstices. These are the primary axis of its current form. The Avenue points to the two solstice alignments, but it frames the geology that was already there. The glacial striations discovered beneath Stonehenge Avenue provide significant insight into the monument's solstice alignments. These natural grooves align with the summer and winter solstices. This suggests that the Neolithic builders may have chosen the location and orientation of Stonehenge Avenue not only for its natural features but also due to these pre-existing glacial formations, which mirrored their astronomical and ceremonial needs, connecting natural forces with their cultural practices. What is more, the alignment of the much older Mesolithic Post holes suggest they were marking this natural feature, bring earth and heavens together into a sacred alignment long before the Neolithic. The work of Terrance Meaden illustrates this further with his observations of the role of shadows at Stonehenge summer solstice (see my previous post Neolithic Astronomy at Avebury Henge…Part 1) that suggest a ritualised sacred marriage between Father Sun and Mother Earth built into both Avebury and Stonehenge stone circles.

A Deeper Connection Between Nature and Culture.

The interplay between natural and human history is evident beneath the Stonehenge Avenue. The aligned glacial striations underscore the fact that the landscapes humans chose for their sacred sites were not merely random; they were influenced by natural forces that predated civilization itself. The Neolithic builders of Stonehenge were working in harmony with a landscape that had already been shaped by powerful geological events. In many ways, this discovery enriches our understanding of Stonehenge, not just as a cultural monument but as a place deeply connected to the Earth’s ancient past. The avenue’s route, possibly influenced by natural glacial formations, adds a layer of intrigue to the already mysterious site. It’s a reminder that human history and natural history are intertwined, with each influencing the other in ways we are only beginning to comprehend.

The Beginnings of Stonehenge

In the old carpark at Stonehenge a remarkable discovery was made. Three, possibly more, ancient post holes were discovered that represent the possible human foundation site of the landscape here at Stonehenge. The Mesolithic postholes at Stonehenge represent some of the earliest known activity at the site, dating back to approximately 8000 BCE and contemporary with the settlement at Blick Mead spring area (see my post on Blik Mead). These postholes were discovered during excavations near the modern-day visitor centre just outside the main Stonehenge monument near the Avenue. There are at least three confirmed postholes, but some researchers suggest that more may exist, scattered across this area.

Location and Discovery.

The postholes were unearthed in the 1960s and 1980s during routine construction work. They are situated roughly 200 meters from the central monument of Stonehenge, near its entrance at the Avenue. These pits contained evidence of large timber posts, which may have been standing monuments or markers during the Mesolithic period. Personally, I strongly suspect they were marking the natural solstice aligned glacial striations that were monumentalised by the Avenue at the end of the Stonehenge building period.

Structure and Contents.

Each posthole was approximately 1 meter in diameter and up to 1.5 meters deep, suggesting that the timber posts they held were substantial in size—likely several meters tall.

The fill of the postholes contained charcoal and other organic material, which was radiocarbon dated to around 8000–7000 BCE, providing evidence of human activity on the site long before the construction of Stonehenge began.

Function.

The exact purpose of these postholes is still debated, but they are thought to have been part of a Mesolithic ceremonial or ritual structure. Their significance is often linked to the possibility of astronomical alignments, making them potentially early markers of the solstice, which as we have seen would later become central to the construction of Stonehenge in the Neolithic. Although the postholes themselves are not as precisely aligned as the later phases of Stonehenge, some archaeologists have suggested that they may represent early attempts to mark key astronomical events like the midwinter solstice. This theory aligns with my suspicions that the site of Stonehenge is all about the geology and positioning of the glacial striations. The alignment hypothesis suggests that the posts at least could have been positioned to frame certain celestial events, such as the rising or setting of the sun or moon. This would have established the site as an important place of observation and ritual, with deep spiritual or seasonal significance to Mesolithic peoples, and a foundation setting for the later monument. While this connection to the solar cycle is speculative it does gain weight from the fact that Stonehenge itself, constructed millennia later, would ultimately be built with a strong alignment to the midwinter and midsummer solstices. The idea that Stonehenge’s significance as a site of celestial observation started in the Mesolithic adds a rich layer to the overall interpretation of the landscape.

Cultural Context.

The Mesolithic people who placed these posts were hunter-gatherers, living in small mobile groups. The postholes suggest that this area had already become a special place long before the famous stone monument was built. Their use of timber—rather than stone—points to different symbolic or ritual practices that reflect the needs and beliefs of the era. The proximity to Blick Mead,  also suggests that this area of the Salisbury Plain was a centre of long-term occupation and importance. Blick Mead’s continual use and potential ritual significance may have influenced the later monumentalisation of the landscape.

Significance.

These Mesolithic postholes provide evidence that Stonehenge did not emerge in isolation. Instead, the landscape had already been a place of ritual and observation for thousands of years before the famous stones were erected. They are critical to understanding the prehistory of Stonehenge, indicating that the site’s sacred importance stretches back much further than the Neolithic period.

Conclusion.

The discovery of glacial striations beneath Stonehenge Avenue offers a unique glimpse into a time long before humans built their stone circles. It speaks to the power of glaciers that once shaped the land and reminds us that the story of Stonehenge is as much about the Earth’s natural history as it is about human endeavour. As we continue to study these markings and the site itself, we gain a greater appreciation for the dynamic forces—both human and natural—that shaped one of the world’s most famous and mysterious monuments. Stonehenge, it turns out, is not just a symbol of human history but also a record of the Earth’s ancient climatic changes and geological past. The Mesolithic people were the first to memorialise this before the later Neolithic pastoralists dramatically changed the landscape during the Stonehenge period. My next post on Blick Mead Palaeolithic site explores these ideas in more detail.

Dr Alexander Peach, Bandung, September 2024.