At http://phys.org/print372520223.html … it seems that coal was formed 300 million years ago just as Pangea was in the process of coming together – or that is the current theory on offer in PNAS (January 2016). This contradicts a popular theory geologists seem to have taken a fancy to over the last few years and this is that coal was formed in the Carboniferous in a 60 million year gap between the appearance of forested landscapes and the evolution of wood eating microbes in between. The idea was that the dead plant matter was buried and fossilised as coal as there was nothing around to break down the plant structure of the new woody plants. One wonders how such a theory took off but the new paper sets out to demolish it – but both theories avoid catastrophism.
We must not forget the prerequisite for swampy conditions as the coal measures display evidence of water having a role in the process of burial and preservation, which is not surprising as we are again talking about estuarine locations. The new research points out that not all the vegetation was actually woody in nature and therefore the fact wood could not be digested by certain small creatures was immaterial. The new research suggests coal was formed as a result of tectonic pressure (the drawing together of the continents in order to form Pangea) and climate change – virtually code for catastrophe. That of course won't go down well with the uniformitarians so we are told other considerations were necessary, as this all took place over millions of years rather than instantly, and therefore a hole was required that could be filled by all this semi tropical vegetation. No hole in the ground – no coal. The holes in this case are between the colliding continents – or as a result of colliding continents. Organic matter was turned to coal over long periods of time. We may note that a lot of this semi tropical vegetation was composed of various varieties of fern – some of which have survived into the modern world in a diminutive form. If ferns at that time were of overlarge proportion how big were the trees?