David, I downloaded the actual journal article and will have a good read of it later on. I did skim through it and I'm quite happy with their interpretation of it being an impact structure. However, I would like to see some evidence for more impact specific structures and mineralogy. Although, the evidence that they have found is consistent with their interpretation of an impact in wet sediments. What is interesting is that its age is coeval with similar sized impact at around the same time that have been confirmed in the Nth Hemisphere (e.g. Chesapeake Bay, Popigai)...around 35Ma. If that is the case, then we have a possible asteroid/fragment train caused by the breakup of a larger body, much like Shoemaker-Levy...possibly a large comet or asteroid that broke up during a collision with another body or during a close approach to the Earth at some previous time in its orbit. Looking at the size of the impacts, they were substantial fragments...at least 4-6kms in size. It's known that the Chesapeake Bay impact did cause substantial local extinctions and it would be interesting to see if this impact caused similar effects in the biota. They occurred in similar circumstances, i.e. shallow continental shelf seas with carbonate-mud shelf sediments.
More work to be done, I guess
