Loess again

2 Apr 2016

A few weeks ago we had an article that associated loess formations with water - a river cutting a channel through the Tibetan Plateau and carrying downstream debris from the eroded rock in that part of the world. This was contrary to normal mainstream thinking in regard to loess formation. The consensus view is that loess is formed by wind as the erosion agent. Not water. It was therefore a surprise to find an article based on field research that actually stated water erosion had caused at least one loess formation in China. Of Course there is a lot more loess in China than could have been produced by a single river cutting a channel through rock that was in its way. In fact, there are immense amounts of loess in China and a lot of it dates to the Pleistocene and earlier as it has the bones of now extinct animals within it (or layered within it). The loess was laid down on more than one occasion. Hence, there would have been multiple melt water events from multiple Ice Ages if water is involved. However, this is not too different from the wind model as loess in China is generally thought to have an origin in tundra conditions on the edge of the ice sheets, blowing dust inland towards East Asia.

Loess is also common outside China and an article at http://phys.org/print378621582.html ... concerns deposits in Iran and Tajikstan. These locations are far from the tundra and the hypothetical ice sheets and therefore another source of dryness is required - and central Asia is envisaged as a massive desert during the Ice Ages. The wind whipped up the sand and dry soil particles and deposited them in the south. Simples.

It involves dust storms that are thought to come in cycles (like the ice sheets). Fundamentally, the wind blown model requires the existence of a substantial source of dust that can only come from arid conditions - hence the idea of a vast desert in central Asia. It is hypothetical but underlies the mainstream theory - as it is necessary. In a water borne model they would have to  explain where the water came from - not easy without a catastrophe of some kind. This explains why they keep saying an arid zone 'must' of existed here ... and here etc. If no arid zone existed their theory is without substance. Basically, the climatic history of central Asia appears to be guesswork. Are the Russians involved? If not why not.

At http://phys.org/print378633631.html ... oxygen depletion in the upper waters of the southern ocean during glacial periods is the subject, a theory is proposed to account for why co2 levels are lower at the Poles than elsewhere. It involves looking at foraminifera plankton shells and analysing them. The evidence confirms what they thought to begin with - co2 levels are higher in warmer conditions than cooler.