Wednesday, July 25, 2007

I know! I know! God did it!.......

Saw this on the 'net last week. You know it's going to be used by creationists as proof of the flood. A paper published in Nature last week proposes that:

...a significant flood event eroded a network of large ancient valleys on the floor of the English Channel.
Of course, the creationists will only read that part, and not the following sections of the abstract (or, let's face it, the whole paper). Reading further:
...we analyse a new regional bathymetric map of part of the English Channel derived from high-resolution sonar data, which shows the morphology of the valley in unprecedented detail. We observe a large bedrock-floored valley that contains a distinct assemblage of landforms, including streamlined islands and longitudinal erosional grooves, which are indicative of large-scale subaerial erosion by high-magnitude water discharges. Our observations support the megaflood model, in which breaching of a rock dam at the Dover Strait instigated catastrophic drainage of a large pro-glacial lake in the southern North Sea basin.
Apparently there were two separate flood events. During glacial periods, the North Sea's connection to the Atlantic would be blocked by ice, resulting in a glacial lake fed by melting ice and many of the rivers of Western Europe. Once that lake filled to the point where it ran over the top of any barriers between it and the Channel, rapid erosion would force a catastrophic failure. The image below shows evidence for the two events - the features suggest that an initial flood carved a broad valley about 45 km across into the bedrock of the channel, and the second carved a number of deeper and narrower channels into the floor of this valley.
It's interesting to speculate that flood events like these are probably responsible for the flood myths we see in many religions - as stories passed down from generation to generation recount memories of local floods, some (as here) clearly catastrophic. No magic sky fairy required.