Subduction and Diamonds

23 Jun 2019

At ... researchers simulate the extreme pressure and heat in the earth's Mantle - or what they assume is the extreme pressure exerted by the Mantle. This is not simulation via computer make believe as they seem to have conducted a genuine experiment - simulating the subduction process and the manufacture of diamonds. I may be wrong but that is how the press release reads - or my interpretation of what they are saying. The idea of the simulation is to understand how diamonds are formed - and conversely to keep the mainstream mantra alive and kicking. Diamonds are crystals of carbon formed in the bowels of the earth and transported upwards by kimberlites (and thence to the surface via volcanic eruptions. Previous research found sodium and potassium was required to form diamonds but the source of these remained a mystery. The experiment, or simulation, was therefore to find a process by which said two chemicals came together in the formation of diamonds - as it was assumed they were a necessary part of that formation. The laboratory experiment involved recreating the pressure and heat assumed to take place during subduction (and assumes subduction is a reality). This is the idea that sea bed plates slide under the continents and subsequently sink into the Mantle. It was thought the subduction process had to happen very quickly so that diamond could be formed before the sea floor plate began to melt itself out of existence.

For the experiment they stacked marine sediments and rocks thought to derive from earth's Mantle in small capsules and then exerted pressure and extreme temperature. At depths equivalent to 120 to 180 km down from the surface (the simulation side of things)  small salt crystals (sodium) began to form between layers - corresponding exactly to the sodium inclusions in diamonds. The sediments provided the potassium. Does this verify Plate Tectonics theory?

At ... Plate Tectonics may have driven the 'Cambrian Explosion' according to a new study - thereby solving another mystery (it is hoped). The Cambrian Explosion is supposed to have happened very quickly as an extinction event provides lots of fossils to mark the end of the period - but why did all this life suddenly explode into existence. That was the dilemma. In a catastrophist scenario there is of course no reason to think those life forms evolved suddenly as it is only the catastrophic event in which the fossils were produced that is recorded in the rocks. The actual process of coming into being could have occurred over a long period of time - but this is not what is required in mainstream gradualist thinking. The fact the geological record does not record earlier life forms is a mystery. It remains a mystery from a gradualist point of view as they assume the rocks record life as it evolved. Therefore the sudden appearance of lots of dead life forms appears to indicate they came into being quickly - and this needs to be explained in a uniformitarian manner. A rise in oxygen levels is thought to be involved and the new study says oxygen levels would have risen as a result of global plate tectonics. It revolves around the idea the continents join up into a series of Pangea like formations and periodically split apart and reform again. The Cambrian Explosion, it is theorised, was preceded by the formation of the super continent Gondwana. There was a remarkable increase in volcanicity as a result of plates bashing up against each other leading to the release of bucket loads of co2 from subducted sedimentary rocks. This supplied the nutrient phosphorous to the ocean in order to drive photosynthesis and oxygen production. Clever stuff by the study authors but reliant on a series of assumptions. Are they right?

At ... we have another extinction event and it is being blamed - on trees. A study published in Scientific Reports claims there is geochemical evidence for the oldest forest in SE North America spreading across a barren continent (a super continent no less) millions of years earlier than previously thought. This is then said to shed light on a global extinction event 360 or so million years ago - and gives 'credence' to a theory that a lack of oxygen in the oceans killed off large dollops of marine life because - those forests dumped nutrient rich soil into the oceans. Credence to some might be incredulity to others. The period in question is the Devonian - long after the Cambrian Explosion. We are told there were three super continents in existence at this moment in time and North American was joined to Greenland and much of Europe. The first large plants with wood tissue (trees) are thought to have evolved in the Devonian (somewhere near modern New York, we are assured). This is now being dated to the Middle Devonian, 380 million years ago, or thereabouts. Not long after, in geological terms, just 20 million years later, we had the extinction event which primarily affected ocean life - trilobites, corals, and plankton for example. At this point a surprising sentence is thrown into the ring. It has been suggested the event was caused by global cooling, volcanism, or an asteroid impact (or all three at the same time). However, the gradualists clearly prefer a more mundane cause and effect and their preferred option is a rapid drop in oxygen levels in the oceans. This study is therefore a proposal in support of the mainstream position and provides its proponents with a hypothetical means for that to have occurred without bringing in a catastrophe (from under the ground or out of the clear blue sky). The appearance of trees in the environment are said to have caused erosion and the leaching of nutrient rich soil into the oceans, even though a barren landscape would have been more open to erosion as it is generally recognised that trees and plants bind the soil together and stop it being dispersed by the wind. I suppose they are thinking that rain can erode peat rich soils - into rivers and therefore into the sea. It might be worth while having another look at this idea of a barren landscape in the Devonian. Did this idea solely come about as a result of a lack of fossils of land animals - or a lack of a catastrophic event creating land animal fossils. It seems quite extreme to have a barren landscape but I suppose it all fits into a uniformitarian landscape where land animals evolved later than marine life. Something else to bear in mind is the creation of soil in the first place. It is basically a composition that includes particles of eroded rock - where the rock surface has been worn down by nature (wind, rain, frost etc). However, it also contains particles of humus, the remains of vegetation digested by bacteria and beetles etc. What came first - the trees or the beetles? It seems like a quite complicated theory - and aired, it would seem, solely to prop up uniformitarianism. A cosmic body impacting in the oceans might explain how marine life was fossilised but land animals were left untouched - but even that theory has problems. A tsunami wave would have also affected any life on land and in its path.