Asteroid impacts could create habitats for life, suggests Chicxulub crater study

Posted by ap507 at Nov 18, 2016 09:21 AM |
University of Leicester scientists part of international research team

Issued by University of Leicester Press Office on 18 November 2016

Images of the team available here: https://www.dropbox.com/sh/oanin803u2qhkmm/AAAWiUCDW7OvcEh38zXJ_5t_a?dl=0

Image captions: Dr Erwan Le Ber is pictured kneeling, with gloves. His colleague from Montpellier (Johanna Lofi), co-author on the paper, is on the picture as well, standing up next to him. This is a part of the ECORD Science Operator team. © DSmith @ECORD_IODP.

Scientists studying a 65-million-year old crater in the Gulf of Mexico, caused by an asteroid impact, claim it could have provided a habitat for early life to take hold on earth.  

The research into the Chicxulub crater, involving a team from the University of Leicester, has shown how large asteroid impacts deform rocks in a way that may produce a suitable environment for early life.

Around 65 million years ago a massive asteroid crashed into the Gulf of Mexico causing an impact so huge that the blast and subsequent knock-on effects wiped out around 75 per cent of all life on Earth, including most of the dinosaurs. This is known as the Chicxulub impact.

In April and May 2016, an international team of scientists undertook an offshore expedition and drilled into part of the Chicxulub impact crater. Their mission was to retrieve samples from the rocky inner ridges of the crater – known as the ‘peak ring’ - drilling 506 to 1335 metres below the modern day sea floor to understand more about the ancient cataclysmic event.

Now, the researchers have carried out the first analysis of the core samples. They found that the impact millions of years ago deformed the peak ring rocks in such a way that it made them more porous, and less dense, than any models had previously predicted.

Porous rocks provide niches for simple organisms to take hold, and there would also be nutrients available in the pores, from circulating water that would have been heated inside the Earth’s crust. Early Earth was constantly bombarded by asteroids, and the team have inferred that this bombardment must have also created other rocks with similar physical properties. This may partly explain how life took hold on Earth.

The study, which is published today in the journal Science, also confirmed a model for how peak rings were formed in the Chicxulub crater, and how peak rings may be formed in craters on other planetary bodies.

The team’s new work has confirmed that the asteroid, which created the Chicxulub crater, hit the Earth’s surface with such a force that it pushed rocks, which at that time were ten kilometres beneath the surface, farther downwards and then outwards. These rocks then moved inwards again towards the impact zone and then up to the surface, before collapsing downwards and outwards again to form the peak ring. In total they moved an approximate total distance of 30 kilometres in a matter of a few minutes.

Professor Joanna Morgan, lead author of the study from the Department of Earth Science and Engineering at Imperial College, said: “It is hard to believe that the same forces that destroyed the dinosaurs may have also played a part, much earlier on in Earth’s history, in providing the first refuges for early life on the planet. We are hoping that further analyses of the core samples will provide more insights into how life can exist in these subterranean environments.”

Dr Erwan Le Ber, at the University of Leicester, and Dr Johanna Lofi at Montpellier are co-authors on the paper as part of the team with responsibility for measuring and interpreting the physical properties downhole and in core. Erwan and Johanna worked on the offshore expedition and during the first analysis phase.

As part of the ECORD Science Operator, research and technical staff from the European Petrophysics Consortium, led by the Department of Geology of the University of Leicester, were highly involved in data acquisition. Recent Leicester MGeol Geology graduates, Laurence Phillpot, Zeinab Adeyemi and Grace Howe, worked as technicians alongside colleagues from Montpellier, Aachen, the Bremen Core Repository and wider Science team providing expertise in physical properties (e.g. porosity and density measurements), producing a first crucial dataset that helped the team to test their models.

Lead for the European Petrophysics Consortium at Leicester, Professor Sarah Davies said: “This is an incredibly exciting expedition where we have provided expertise and equipment to support an international team of scientists. Our own early career researchers have had the opportunity to make a significant scientific contribution through their involvement in the initial research.”

The next steps will see the team acquiring a suite of detailed measurements from the recovered core samples to refine their numerical simulations. Ultimately, the team are looking for evidence of modern and ancient life in the peak-ring rocks. They also want to learn more about the first sediments that were deposited on top of the peak ring, which could tell the researchers if they were deposited by a giant tsunami, provide them with insights into how life recovered, and when life actually returned to this sterilised zone after the impact.

Notes to editors:

‘The formation of peak rings in large impact craters’, published on 18 November in the journal Science.

About the European Petrophysics Consortium (EPC)

The EPC involves three European universities: University of Leicester (UK); University of Montpellier (France); and Aachen University (Germany). The EPC undertakes petrophysics research and combines borehole geophysics, laboratory experiments and geology. The central office is located at the University of Leicester and is responsible for management of the consortium. Leicester represents the EPC within ECORD (European Consortium for Ocean Research Drilling) and IODP (International Ocean Discovery Program). The ECORD Science Operator (ESO) undertakes mission-specific platform (MSP) operations for ECORD on behalf of IODP. ESO is a consortium involving operations (British Geological Survey), curation (University of Bremen), downhole logging and petrophysics (EPC).                                                                                                                                                                                                                                                   

About the International expedition to the Chicxulub impact crater

The expedition was conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition is also supported by the International Continental Scientific Drilling Programme (ICDP). The expedition would not have been possible without the support and assistance of the Yucatán Government, Mexican federal government agencies and scientists from the National Autonomous University of Mexico (UNAM) and the Centro de Investigación Científica de Yucatán (CICY).

University of Leicester contact details:

Erwan Le Ber

E: elb51@le.ac.uk

 

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