A piece of petrified wood with big implications

3 May 2021

William sent in the link to this story at www.yahoo.com/news/odd-fossil-found-mississippi-gravel-193528501.html ... and see also www.sunherald.com/news/nation-world/national/article250582244.html ... a rock found in central Mississippi has intrigued geologists. It is actually a piece of petrified wood - wood turned into stone. It was found deep in the ground, in sediments, including gravels, that are thought to be 100 feet deep. Naturally, the wood was dated to the time of the sediment laying down, during the Pleistocene. Now, after examination of the rock, or petrified wood, there is evidence it had been dragged along due to cut marks, for want of a better term. Cut marks as in abrasions caused by being dragged along. However, that is only the half of it as it has now been determined the fossil is older than the sediment within which it was found. It had become caught up in a meltwater rush of water from a melting glaciation, chewed out of the ground and dragged all the way down to Mississippi. A distance of hundreds, possibly thousands of miles is involved. At first, it was assumed it had travelled on the underside of a glacier, the normal interpretation for similar finds. However, there was never a glaciation as far south as Mississippi. It is just too distant from the ice sheet [of the Late Glacial Maximum for example]. Hence, geologists have had to accept that a meltwater pulse running down through the Mississippi river valley was responsible. It is described as a massive drainage ditch, with a huge amount of water ending up in the Caribbean Sea and the Atlantic. They now think outwash also occurred during earlier glacial events, quoting a date of 700,000 years ago for the formation. Back then the river was 15 miles away from its present position. However, do they take into account the fact a massive pulse of water would have involved the river running over its banks and causing streams of water to diverge from the course of the river, but ending up down in Cajun country.

Water rather than ice appears to be what caused the fossil to move. As the petrified wood is older than the sediments it must have been chewed up by the same watery outwash, suggesting the water was moving fast as well as powerfully. It sounds a great deal more violent than outwash, enough to cause silts and sands and gravels, as well as mud, to form a huge geological deposit. It may smack of a rapid melting of the ice, rather than a prolonged melting around the edges of the ice sheet. One could hazard a guess and say that might occur during pole movement - the ice sheet moving into a more temperature climate zone. However, the core of the glaciation, on the Canadian Shield, would have persisted for longer. One can look at the famous Scablands in the NW of the US, caused by the melting of the glaciers on the Cordillera. That involved a huge flood of water. It left gouges in the ground after its passage. The Mississippi flood left a heap of sediment - 100 feet thick. The contours of the region differed to those of the Scablands. One was a route down from the mountains and the other a splurge across a flat sort of landscape, a broad river valley.

Several interesting points emerge from this recognition, the serrations on the fossilised wood. There may be other examples that have been dated by the date of the gravels they were found in without anyone questioning that fact. In this instance, somebody did have the presence of mind to question it, and make his thoughts public. It also opens a hornets nest the geologist may not have intended. If glacial melt water could bring lumps of rock as far south as Mississippi where does that leave all the erratics normally dated to glacier movement. Might water have been involved in some of them. The discovery may lead to a reappraisal of the extent of former ice sheets as erratics are often touted as being pushed forwards by the snout of a glacier - especially in landscapes that are on a decline. In this instance, on the flat, that cannot so easily apply, and that must also be a factor in lots of other erratics around the world. Clearly, meltwater outwash should play a more prominent role that it does at present, in standard geology explanations.

Another point not in the thinking as yet is the manner of the ice melt. Was it rapid or a slow process. How does the latter explain the chewing up of the ground in the passage of the water. Geology has already accepted the occurrence of megafloods as a result of ice dams collapsing, a rather dubious process. Will they now be forced to think in terms of meltwater pulses independent of ice dams. They were able to reduce the catastrophic nature of the scablands by posing the idea of a succession of ice dam collapses on the way down from the high mountians but is that feasible in a lowland location. Neutering catastrophism is one thing the uniformitarians have been successful at, but in the case of accumulating evidence, which arrives more quickly than it did in the past, may be a bridge too far.