Bone Bed Dakota

2 Apr 2019

The K/T boundary vent is back in the news - see www.sciencedaily.com/releases/2019/03/190329144223.htm ... in the aptly named Hell Creek formation in North Dakota we have a bone bed laid down by a giant wave - or waves. There is a certain amount of scepticism abroad amongst other geologists and paleontologists - but is that sour grapes. Or is it all just too neat. Nobody is disagreeing that such a bone bed should exist if the asteroid strike had caused the demise of the dinosaurs but usually, geology is thought to distance the event from the actual disappearance of the dinosaurs (by sedimentary layers). In other words, some geologists have faith in the uniformitarian dates for such sedimentary layering whereas others might point to the Mount St Helens eruption when thick layers of sedimentary material formed in days - if not in a matter of hours.

One should therefore employ some scepticism towards both points of view. The researchers have been working on the site for a long time and now say that violent shaking raised giant waves in the waters of an inland sea - followed by a rain of glass (tektites) and landscape fires. In the water fish struggled to breathe. The heaving ground and seich of water developed into a huge wall of water tossing hundreds if not thousands of fish such as sturgeon and paddlefish on to a sand bar. Fossilised fish were found stacked up on top of each other and mixed up with tree parts and vegetation, dead animals, massive bone inserts, and part of a Triceratop (dinosaur) with a great quantity of micro organisms etc. This is the first definite mass death assemblage directly linked to the K/T boundary event, we are told, which is why there has been a certain amount of disbelief. The researchers discount a tsunami wave as they rush forwards and then tend to recede straightaway. The researchers decided some other wave action was responsible for dumping the bone bed. They have suggested seismic waves induced by the impact on the Yucatan peninsular formed within 10 minutes of the impact - or less.

One find was a charred log or tree trunk 4m in length and covered in amber. The rain of ashe and debris actually covered the tektites proving that they rained down after the central impact (blasted on high by the explosion).

See also www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died/ ... which describes the whole story in some detail - including the nature of the K/T boundary. Very good read.