It’s wet and miserable here at the farm so I am browsing the internet and stumbled over some geological descriptions of Ellesmere Island and its coal beds that contain, would you believe un-coalified wood.
Here’s one description:
At the site where I worked on Ellesmere Island, there were large Metasequoia logs and tree stumps still rooted in situ in the coal layers. Picking apart the coal layers, I could pull out Metasequoia leaves, twigs, and male and female cones. The siltstones between the coals preserved beautiful fossil impressions of a variety of tree leaves and stems.
And a photo showing an example:
(Metasequoia stump in its growth position, Stenkul Fiord, Ellesmere Island
(photo by Anne Jefferson))
Coal is supposed to form from the result of the burial of vegetation by the application of vertical pressure. Here we have coal beds outcropping with insitu tree trunks sitting in coalified vegetation but which contain un-coalified remnants of tree trunks and what nots.
It reminds me of December 1975 when on a Macquarie University Geology Society (MUGS) trip to Tasmania and Victoria we visited the Morwell open cut lignite mine. There too one could see beds of smashed up forests and upright tree trunks that were snapped off a few feet from the ground, now represented by the sedimentary lignite deposit (brown coal).
So how do you produce coal? If compression due to burial is your answer, then you have a problem, like that at Ellesmere Island, because this mechanism of vertical compression from burial is not observed empirically. Those tree trunks should have been flattened and turned into coal. They have not, and thus the explanation fails.
The more likely explanation is that the buried vegetation was preferentially replaced by the deposition of carbon from upwelling methane from the Earth’s mantle.
All rather unsettling, no?
Next thing they will be asserting diamonds are formed from compressing coal!