French Cave yields startling find
Broken stalagmites forming two circles within a deep cave in France are reported in the journal Nature this week and dated to 176,000 years ago. Stalagmites are limestone objects on the floors of caves, formed as limestone bearing water drips from the cave ceiling. No stone tools of fossilized human bone were found in the cave, called Bruniquel, but as the only hominins in the region at that time were Neanderthals, this is believed to be a Neamderthal site.
There is evidence of controlled fire, comprising both charcoal and burnt limestone. Charcoal contains carbon but radiocarbon dating is not possible beyond 50,000 years and so dating was achieved by means of uranium series. Uranium series is also known as uranium thorium (UT) dating and relies upon various frabctiond of the isotope U230 in the sample.
Inasmucch as no artifacts other than the broken stalagmites arranged in two circles were found, it is inferred Bruniquel Cave was a ritual site and not an occupation site. The large chamber in which the circles were found is over 300 meters from the cave entrance.
Read the Nature article "Early Neanderthal constructions deep in Bruniquel Cave in southwestern France"