Layering of Loess

20 May 2010

At Nigel Calder has a post on the 1960s discovery by Czech geologist George Kukla, who counted the layers of loess, each separated by darker bands of material thought to be left over from warm interglacial periods. Kukla found too many layers of loess - and this did not fit into current thinking. Until then everyone had been thinking in terms of just four Ice Ages. Cesare Emiliani had found traces of variations in heavy oxygen seabed fossils and had said there were seven Ice Ages - which received your usual academic response (we know best). Kukla went further - he counted nine loess layers. These are thought to be windblown mineral dust ground down by glaciers - but Allen and Delair would beg to differ. Nowadays, there is thought to have been more than nine glaciations within the last 3 million years but Kukla is back in favour it seems ... but read the story.

At reports on the May 13th issue of Nature and the discovery of early Ordovician marine animal fossils - with preservation of their soft body parts (fossilised), some 1500 of them (in SE Morocco). They include sponges, tube worms, molluscs and crabs - one of the latter being a species that is still living today (480 million years later). The Cambrian Explosion was followed by the Great Ordovician Biodiversification Event - which represents a huge increase in the number of fossilised marine animal genera. In addition, Burgess shale fossils, thought to have died out in the Cambrian event at 499 million years ago, appear to have survived into the Ordovician (on the Morocco evidence) - or at least until the boundary event. The soft bodied fossils appear to have been buried fairly rapidly - by bottom sediments it is assumed but catastrophically is the other option.

At we are informed that in nature evolution takes place over eons of time, a slow accumulation of adaptations gradually produces new traits and new species. However, in the laboratory evolution can take place very quickly. It is known as directed evolution, a process to discover new proteins that do not occur in nature (as far as it is known) to produce new drugs to treat ailments (such as cancer), new microbial enzymes to convert yeasts into biofuel, and imaging agents for magnetic resonance imaging. Most proteins are complex and it is difficult to predict how they might alter their structure and function. Trial and error methodology is used and occasionally a new protein with desirable traits is produced - in a fraction of the time it is thought to take place in nature.

Meanwhile, at May 13th ... a paper in Science indicates water and other big volatiles may have been present in some of earth's original building blocks. This convenient theory is able to sidestep the idea earth aquired water from comets.