Kerguelen, and drumlins

22 Apr 2011

The idea of the geoid readjusting itself as a result of changes in the axis of rotation may not be acceptable to academic geology but it might explain a story in New Scientist 20th February 1999. An ancient land in the Southern Ocean is a geological fact of life. The Kerguelen Plateau, situated between Australia and the Antarctic, has on at least three occasions been dry land. Marine geologists discovered this piece of continental shelf system was formerly above sea level as sediments were found containing plant spores, seeds, pollen, fragments of wood and charcoal. Geologists speculated that periodically the crust was pushed up by intense volcanic activity - a magma plume. However, it is a more simple explanation to think in terms of the geoid changing and the world's oceans realigning themselves as a result of this.

In Scientific American of December 1989, John Shaw, a physical geographer of Queens University in Kingston Ontario, thought drumlins in northern Saskatchewan were ambiguous. Shaw suggested they were associated with melt waters as they resemble features in stream beds caused by turbulence - fast water flow. Such drumlins  might form, we may note, looking at it from a catastrophist angle, during a rapid retreat of a polar ice cap. Shaw, in a paper published in Geology proposed that the drumlin fields of Saskatchewan, and there are lots of fields and not just drumlins themselves, came about as a result of a turbulent floods of melt water that raged beneath the North American ice sheet at the end of the Ice Age. Flood waters scoured pits on the underside of the ice and debris carried by the surging water accumulated in cavities and was milded into long narrow hillocks which remained on the landscape after the ice itself had disappeared. In conjunction with the drumlins, we may also note, there are a multitude of lakes, ponds, streams and bogs with a direct origin in the ice sheet. 

A paper in the Journal of Coastal Research, a Special Issue, No 17, and Fletcher and Sharma, 'Submerged shorelines on O'alu, Hawai'i; an archive of episodic transgression during the deglaciation?' - which again is a piece of geology subject to controversy. O'alu has a shallow submerged slope, formed in a stepped topography, a series of sand covered shelves separated by eroded palaeo-reef. One of the shelves dates back to the end of the Ice Age when sea level change occurred. However, another shelf was said to date from the Younger Dryas period - end of Pleistocene event, and another rapid change in sea level at the  end of the Boreal and transition to the Mid Holocene Warm Period. In the periods between rapid rise the reef systems developed normally - so what are we seeing here? Three transgressions associated with a rapid change in the earth's geoid and the oceans readjusting themselves to the new axis of rotation? One is bad enough for uniformitarians to swallow - but three of them?

Penny Barton and Rosy Wood (Cambridge), 'Tectonic evolution of the North Sea basin; crustal stretching and subsidence' (1984) published in the Geophysical Journal of the Royal Astronomical Society say that the lithosphere model for the stretching of sedimentary basins such as the North Sea is associated with crustal thinning and basement subsidence that took place over a long period of time - going as far back as the Jurassic. The basin has been stretched by some 70km, and as such, we may note, recent sea level change in the North Sea would appear to be due to a change in the geoid rather than seismic factors, the oceans readjusting themselves after an 'event' of some kind and in this instance, flooding a large section of the continental shelf system around NW Europe. It is significant that this is generally dated to the last of the shelf systems' transgression events, on Hawai'i, namely at the end of the Boreal (around 6000BC).