Robert sent in some interesting links. At https://www.livescience.com/archaeology/5-catastrophic-megathrust-earthquakes-led-to-the-demise-of-the-pre-aztec-city-of-teotihuacan-new-study-suggests …. the gist of the paper is that evidence of earthquakes found at Teotihuacan caused the demise of the pre-Aztec Mexican civilisation. Whereas that might be considered a catastrophic conclusion it is spoilt by the fact that at that point in time, from AD100 to 700, the Roman Empire also experienced some dramatic earthquakes. At Antioch, for example. The study comes from data from an analysis of three large pyramids in the city. They display distinct evidence of earthquake damage. Yet, they also say the pyramid was structurally altered in order to make it more resistant to earthquakes, and the dramatic fall in population did not occur until the 6th century AD. In the Roman world we have at least three major pandemics within that period – and that contributed to a drop in population numbers. So much so the Arab armies were able to take advantage of the situation and quickly take over the Levant and Middle East, and later, North Africa and Iran. In the aftermath of the Mexican de-population event it led to the rise of the Aztecs. Hence, we might assume a pandemic affected them – possibly at the same time as the Justinian Plague.
The second link … https://www.livescience.com/planet-earth/microbiology/hidden-biosphere-of-extreme-microbes-discovered-13-feet-below-atacama-desert-is-deepest-found-there-to-date … Microbial life in deep sediment layer. Robert comments – is this evidence of Thomas Gold’s deep hot biosphere. In this instance, not so deep.
The third link is https://www.livescience.com/planet-earth/geology/its-had-11-billion-years-to-accumulate-helium-reservoir-in-minnesota-has-mind-bogglingly-large-concentrations … discovery of an enormous reservoir of helium in Minnesota. Helium is scarce on earth – but abundant in the universe at large. Normally, helium is obtained as a by product of natural gas production. It accumulates underground in pockets of methane and other hydrocarbons. In Minnesota the helium exists without hydrocarbons, it would seem. It forms via nuclear fusion or the radioactive decay of uranium and thorium. Helium is found in Greenland and East Africa, for example, in granite rocks rich in uranium and thorium – as well as a rift system that opens up the rock and exposes the helium. Robert adds – here we see helium in igneous rocks. Thomas Gold actually suggested hydrocarbons might exist in igneous rocks but because the consensus geology view saw hydrocarbons as top down fossil fuels igneous rocks have hardly ever been explored to find hydrocarbon deposits.