The Pleistocene epoch, which began 2.6 million years in the past and lasted till about 11,700 years in the past, was crucially essential for our hominin ancestors.
Homo sapiens first developed on this period, about 200,000 years in the past. Then, within the latter interval of the Pleistocene, our ancestors began to show indicators of cognitive complexity: amongst different improvements, they made extra refined instruments, started to reap seafood, used compound paints and adhesives, engraved objects with geometric designs and strung shell beads.
A few of these historical people lived in and travelled by way of what’s immediately South Africa’s Cape south coast. They, like the various animals that occupied this house, left their tracks in aeolianites, the cemented stays of dune surfaces; the oldest of those surfaces are round 400,000 years outdated and the youngest are about 35,000 years outdated. One hominin tracksite that our analysis workforce discovered, at Brenton-on-Sea on the Cape south coast, contained 40 human footprints relationship again round 90,000 years. Since then we’ve identified an extra three hominin tracksites. Previously reported sites from the Cape’s east and west coasts convey the entire variety of reported Pleistocene hominin tracksites in southern Africa to 6.
These rock surfaces do not simply present the place and the way our ancestors walked or jogged. In addition they reveal how they foraged or left stone tools – and made patterns within the sand. The patterns that we’ve discovered consisted of circles, grooves, “hashtags”, fan shapes and even what gave the impression to be a sand sculpture that resembled a sting-ray. In our research paper about these discoveries, we launched the time period “ammoglyph” to explain a sample created by people in sand that’s now evident in rock.
Now we have discovered two new triangular patterns that we consider are ammoglyphs. That is but more evidence that South Africa’s shoreline is a spot the place our human forebears turned truly modern. Right here they developed the complicated cognition that defines us immediately.
It seems that the realm’s dunes and seashores shaped an enormous canvas of sand on which our ancestors may go away their mark, maybe in the identical approach that immediately we get pleasure from inscribing patterns on the seaside or making sandcastles with our children. Remarkably, these surfaces at the moment are amenable to our inspection and interpretation, if we all know the place to look.
This latest discovery got here in 2019. Three members of our analysis workforce had been exploring a rugged and distant stretch of shoreline at low tide, looking for newly uncovered tracksites. As we clambered over a bunch of rocks and regarded up, we may hardly consider our eyes. Forward of us, on a big rock that had tumbled down from the cliffs above, was an association of linear groove options that shaped a near-isosceles triangle, full with an virtually excellent bisector.
The edges of the triangle had been near a metre in size. Our first query was whether or not this could possibly be modern graffiti. Thankfully we had been simply capable of exclude that risk, as disturbance of the underlying layers of rock implied that this triangular function had been created when the floor was sand, not rock.
We documented the location and took pictures for photogrammetry, so we may generate digital 3D photos.
After we returned a number of weeks later we had been amazed to discover a comparable however smaller rock proper beside the rock we had initially recognized. It additionally contained a triangular function, however this time a near-right-angled triangle. It possible got here from the identical unique floor, and excessive tides should have overturned it since our preliminary go to.
These triangular options, we argue in our new paper, are in all probability ammoglyphs. Geological correlation to a dated website about 2km to the east suggests an age vary of between 130,000 and 80,000 years, however we do not but know precisely after they had been made; we’ve submitted rock samples for relationship research and hope to have these outcomes quickly.
The world the place we discovered the triangular options is comparatively near Blombos Cave. This website is internationally well-known due to what will be termed its “palaeo-art”, epitomised by an engraved piece of ochre and an abstract drawing.
The engraving sample at Blombos Cave has been analysed by quite a few consultants, with various interpretations. Nonetheless, it will possibly clearly be thought to be a collection of triangles. Might what we’ve discovered and described symbolize a model of this sample on an unprecedented, massive scale? In any case, it might have been simpler for our ancestors to inscribe a big sample in sand utilizing a stick than to have to hold ochre an extended distance to a cave after which meticulously get to work on engraving. For now, till we discover extra examples, that is pure hypothesis. However it’s an intriguing risk.
It’s also thrilling to suppose that the document of historical artwork could possibly be deepened by these kinds of finds. Examples of palaeo-art grow to be much less widespread with growing distance in time, partly as a result of some supplies like bone or wooden or rock artwork deteriorate sooner than others, like stone. Some researchers have lamented how a lot historical artwork should have been created in perishable supplies and, so, been lost to the archaeological record.
With the emergence of potential ammoglyphs on South Africa’s Cape south coast, it seems that such a lament could have been untimely. The addition of sand as one other medium by way of which palaeo-art can probably be recognised is an sudden growth within the understanding of our human origins – and is one thing to be cherished.