At www.q-mag.org/neanderthal-the-painter-and-installation-artist.html … we have already dealt, last week, with the cave paintings ascribed to Neanderthals, but we now have something just as remarkable – Neanderthals constructing a concentric ring of stalagmites deep inside a cave. In the cave of Bruniquel in France (Tarn et Garonne) they built a circular structure made out of 400 sawn off pieces of stalagmite (but what they used as a cutting tool is as yet unknown). They form two concentric circles – a design we usually associate with modern humans in the Neolothic megalithic era. It is also supposed stone circles have a focus on the sky but a circle inside a cave could hardly have anything to do with heavenly alignments (unless it was a replica of something also existing outside the cave).
… The stalagmite circles are said to weight 2.2 tons in gross weight. They were discovered in 1990 by a budding speleologist (a new dating method using stalagmites and other cave deposits). The cave had underground lakes, floating calcite, translucid draperies, and various concretions – and it also had the bones of Pleistocene animals and evidence of bear lairs. Some 336m inside the cave was the stalagmite circle. In the vicinity was the evidence of fires – camp fires. Using C14 to date a piece of burnt bone they came up with a date of 47,600 years ago. However, this is the very upper limit date that C14 methodology can produce and therefore all this date meant was that the burnt bone was probably older than that date.
The cave was then ignored until 2013 until a Belgian scientist came across a reference to it during a visit to the region. She was a cave specialist and went on to recruit some well known French fellows and they explored the circle in earnest. Using the uranium-thorium methodology they came up with the astonishing date of 176,500 years ago. The date was so outrageous they had to double check it.