Chicxulub crater Leicester researchers investigate what killed the dinosaurs

A team of scientists, including University of Leicester researchers, has now reached the midpoint of an International Ocean Discovery Programme investigating the Chicxulub crater site - the location of the meteorite impact associated with a mass extinction event 66 million years ago that wiped out most forms of life and is largely believed to be what killed the dinosaurs.

Situated off of the coast of Mexico, the Chicxulub crater is the only impact crater on Earth with an intact peak ring: a circular structure within the crater also observed on other rocky bodies and planets such as the Moon or Venus.

"Leicester is very much involved in part of the operations, so we're the team providing the expertise and the equipment to a certain part of the science to support the scientists," said IODP Group Principal Investigator Sarah Davies, Professor of Sedimentology in the University of Leicester's Department of Geology. This is a mission-specific platform expedition conducted for IODP by the European Consortium for Ocean Research Drilling (ECORD). The operations are undertaken by the ECORD Science Operator, comprising the British Geological Survey, the University of Bremen and the European Petrophysics Consortium in which the University of Leicester is the lead.

Professor Davies added: "At Leicester, we provide equipment and people to take measurements on the rock that we bring back to the surface. We call that core. That core is then put through a piece of equipment that measures different properties of the rocks." How magnetic the rocks are and what their density is are just a few of the many properties being measured. "Once the core has been taken out, you're left with a hole beneath the sea floor and we put tools into that hole to measure again the properties of the rock."

Due to its involvement with ECORD, the University of Leicester mounts various different expeditions and has been playing a unique role in this one: Two members of the IODP Group in the Department of Geology - Dr Erwan Le Ber and 2015 Leicester graduate Laurence Phillpot - were on the drilling platform, with Dr Le Ber being offshore for the entire expedition. Alongside partners from the UK, France and Germany, they undertook downhole logging in situ measurements and measured the physical properties of the cores received.

Speaking to Nathan Ifill from the University of Leicester News Centre, Professor Sarah Davies and Dr Erwan Le Ber have been giving an overview of the project, how the University of Leicester is involved and where they have got to to-date.

The project hopes to shed light on what caused the changes which lead to the mass extinction 66 million years ago; how rocks are weakened when craters are formed during large impacts; and how peak rings such as the one at the Chicxulub crater are formed and what they consist of. Another question that researchers will be trying to address is whether the impact was so violent that the Earth's rocks behaved like a fluid.

"The expedition aims to address several questions including: 1) what rocks comprise a topographic peak ring and how are peak rings formed; 2) how are rocks weakened during large impacts to allow them to collapse and form relatively wide, flat craters; 3) what caused the environmental changes that led to a mass extinction and what insights arise from biologic recovery in the Paleogene; and 4) what effect does a large impact have on the deep subsurface biosphere and can impacts generate habitats for chemosynthetic life?" - ESO - Chicxulub K-Pg Impact Crater Expedition 364

The team at Chicxulub drilled into the crater to a maximum depth of 1334.69m and cores of rock were retrieved from up to 828.99 metres beneath the sea bed. The samples and data collected will improve our understanding of the physical, environmental and biological processes involved both during and immediately after such a dramatic event.

Summary of IODP Expedition 364 Offshore Phase

  • Number of holes: 1
  • Number of expedition days: 55
  • Total depth drilled: 1334.69m
  • Open hole drilled: 0-505.7m
  • Length cored: 828.99m
  • Length recovered: 839.55m
  • Recovery: 100%
  • Number of core bits used: 8
  • Number of cores: 303
  • Number of sections: 830
  • Number of samples: 1075
  • Total length of open hole downhole logs: 5.8km
  • During the expedition, astronaut Tim Peake tweeted a photo of the crater from the international space station.

    The drilling has been taking place off the coast of Mexico, near the town of Chicxulub after which the crater is named. The crater itself is more than 180 kilometers (110 miles) in diameter and is over 20 kilometers (12 miles) deep and is partially buried under the Yucatán Peninsula.

    As the crow flies, the Chicxulub crater is situated almost 5,000 miles away from the University of Leicester campus.

    Understandably, the expedition has generated significant media interest: Articles about the project have featured on BBC News, CNN, Science, the Daily Mail and The Conversation.

    The next phase of the Chicxulub crater expedition will take place at the IODP Bremen Core Repository, Germany in October 2016. This exciting project will continue to generate exciting scientific discoveries over the coming months and years. To keep up-to-date with all of expedition developments, follow @EPC_Research on Twitter.