Dear colleagues
There is a 55 minute program tonight on Catalyst at 8pm EST, about the Chicxulub asteroid impact IODP Expedition 364 drilling in mid 2016. The blurb about it says “The day the dinosaurs died: takes a look at the expedition now underway to drill into the Chicxulub asteroid impact crater in Mexico”. This was filmed aboard the ship, as I remember it by the BBC.
The story is of course a great one, with the asteroid impact forming a crater 180 km across, the resultant incredibly hot rock debris spreading around the Earth, starting fires and wiping out sunlight for perhaps two years, and generating tsunamis that piled up metres of sediment in what is now central Texas and elsewhere. The result was the extinction of most plants and animals, the end of the dinosaurs and the rise of the mammals – leading in the end to that pinnacle of evolution, us.
The drilling was by a jack-up rig in shallow water in the Gulf of Mexico off Mexico, and it drilled hundreds of metres of the early Tertiary shallow water limestones deposited later at the site, the relatively thin tsunami deposits that formed in a few hours 66 million years ago, and the shattered and melted granitic rocks that had been forced down ward before rebounding upward to form a rim around the crater wall. The hole was drilled over two months and recovered an almost complete set of sediment and rock cores to the total depth of 1334 m below the sea bed – a wonderful success…
The aim of the expedition was to understand the sequence of events recorded in the cores, including the nature of the impact and its mechanical and chemical results, the impact of moving fluids in the shattered rock, the recolonising of some of the rocks by microbes, and the explosive evolution of new marine organisms over tens of thousands of years, to completely fill the niches emptied during this world-wide catastrophe.
This is a marvellous story and the drilling was a spectacular example of how science builds on existing theories by very innovative experimental methods. The results are now coming out in scientific literature, and some early results may perhaps be covered in this TV program. It is a huge credit to IODP (International Ocean Discovery Program) of which we are members. There was an Australia-based scientist, Marco Coolen, aboard.
For those who cannot watch it tonight it will be replayed at 3 pm on Saturday and be available on IView.
This should be quite a show and is a great piece of publicity for IODP as we are starting a new phase of scientific drilling expeditions in our region.
With regards Neville
