When miners were sinking a ventilation shaft for the new Crinum Coal Mine in Central Queensland in 1993 (see map below) they unearthed a rare find.After digging through the thin surface sands and clays, followed by basalt, 21 metres (almost 69 feet) down they found pieces of wood entombed in the bottom basalt flow.The K-A ages provide another strong correlation of the odd phenomenon observed by the RATE Project.That there was evidently a burst of much accelerated radioactive decay at some point in the past. G'day Andrew, Congratulations on a very interesting article.
The bottom two images are of basalt with holes from former gas bubbles (left) and visible fossil tree roots in siltstone.
The pieces of wood recovered by the miners were examined and photographed, as too was the leaf imprint, but access to the ventilation shaft was not possible, nor were samples of the enclosing basalt available, having long been dumped with all the other rubble and waste rock.
However, an exploratory hole had been drilled close to where the shaft was eventually dug.
The local geological context makes the basalt flow approximately ‘30 million years old’, in keeping with other basalt flows in the region all regarded as of Tertiary age (in the conventional terminology).
Since the tree trunks were entombed in the basalt lava, the wood is thus supposedly at least 30 million years old.