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Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
Scientific deep drilling in an impact structure to detect the traces of mass extinction of species 65 million years ago at the Chicxulub crater, Mexico
International Continental Scientific Drilling Program ICDP:
Deep Impact and the Mass Extinction of Species 65 Mio. Years Ago
Chicxulub workshop at University of Merida, Mexico
From March 22 to 24, Professors Jaime Urrutia-Fucugauchi and Dante Morán-Zenteno of the Universidad Nacional Autónoma de México are organizing at the University of Merida an international workshop on the drilling of the Chicxulub crater. This workshop is co-sponsored by the International Continental Scientific Drilling Program (ICDP), an organization, financed by the United States, Germany and China, to support research projects which require deep drilling to understand specific Earth processes. The aim of this Merida workshop is to bring together Mexican scientists and international experts on cratering and mass extinction to plan the deep drilling of the Chicxulub crater, which
is believed to have caused the extinction of the dinosaurs, some 65 million years ago.
Chicxulub and the Cretaceous-Tertiary boundary problem.
Some 65 million years ago at the boundary between the Cretaceous (the last geological period of the Mesozoic) and the Tertiary era, a large asteroid came rushing out of space at a velocity of more than 15 km per second and impacted the Earth at the tip of the Yucatan platform.The enormous amount of energy generated by this impact, equivalent to 10 thousand time the whole world nuclear arsenal, lofted in the atmosphere huge quantities of dust particles and gases.The asteroid penetrated the Earth's crust down to a depth of more than 20 km; on its way it vaporized melted and shattered the Yucatan target rock composed of carbonate, evaporite and granite. As a result, a crater some 200 km in
diameter formed. Over a short period of time (a few minutes) several hundred billion tons of CO2, SO2 and water vapor released by the vaporized target rock were injected into the Earth atmosphere. An abrupt and global perturbation of the Earth System followed: the climate and the oceans became unstable, the fine dust suspended in the atmosphere blocked sunlight, decreasing or stopping photosynthesis.
This ecological catastrophe is believed to have caused the famous Cretaceous-Tertiary (KT) boundary mass extinction which saw the demise of the dinosaurs and more than 50% of the Earth fauna and flora on land and in the oceans.The hypothesis that a asteroid or comet impact induced the mass
extinction at the KT boundary was first proposed in 1980 by a team from the University of California at Berkeley led by Nobel price winner physicist Luis Alvarez and his geologist son Walter.Very controversial at first because of its catastrophic aspect, this hypothesis was confirmed in the early 1990 when scientists realized that the impact
structure which laid buried under approximately 1 km of Yucatan platform sediments was in fact the long sought KT boundary crater predicted by the Alvarez hypothesis.
This huge bowl-shaped structure, centered at Puerto Chicxulub near Merida is clearly outlined by gravity and magnetic geophysical anomalies.It had first been identified as a potential impact crater by geophysicists Antonio Camargo-Zanoguera and Glen Penfield while exploring for Pemex the potential oil reserves of Yucatan. The structure had been drilled, although unsuccessfully for oil. In the early nineties, studies of the recovered core samples confirmed that the Chicxulub structure was indeed a huge crater.
Dating of the impacted lithologies indicated that it was precisely of KT boundary age, coeval with the mass extinction of organisms. Exactly how the Chicxulub impact induced the perturbation of the Earth System and the mass extinction of organisms is not yet fully understood.The study of the crater and its internal lithology in the framework of an ICDP scientific deep drilling project will provide answers to this fundamental question.
Cratering an important process in the formation of planets.
The ICDP deep drilling project in the Chicxulub crater will also help Earth scientists to better understand the mechanisms of crater formation.Cratering is a key process in formation and evolution of the rocky planets.
With a diameter of approximately 200 km in diameter Chicxulub is one of the largest and best preserved crater on Earth. Chicxulub can thus serve as a prototypical and accessible large planetary impact structure providing key information as to the formation and early evolution of Earth and on both dry (Moon, Mercury) and volatile-rich planets (Mars, Venus).
Significance.
The goal of the Merida meeting is to design a plan for the deep drilling of the Chicxulub crater, discuss potential drilling sites,define the scientific questions to be adressed,evaluate logistical needs and outline scientific collaborations and research strategies.
Drilling a hole several km deep in such a unique and key location as the Chicxulub crater will be a major technical and scientific achievement. It will greatly increase our understanding of the fundamental processes which influence the biological and geological evolution of the Earth such as impact induced mass extinction, and the formation of large
craters on the Earth and the other rocky planets. From the technical point of view much can be learned in term of
drilling, coring and well-logging techniques from a deep drilling project in the Chicxulub structure.Expertise and experience acquired during other ICDP supported drilling projects such as the more than 9 km deep KTB borehole (German Continental Deep Drilling Program, today the
Deep Crustal Laboratory of the GFZ Potsdam which provides the Operational Support Group of ICDP) in north-eastern Bavaria will be applied and refined.
Major technology transfers, scientific exchanges and education opportunities will take place between scientists, students, engineers and technicians from the different
nations involved in the ICDP Chicxulub deep drilling project.
GEOFORSCHUNGSZENTRUM POTSDAM (GFZ)
GeoForschungsZentrum, Public Relations, Telegrafenberg, D- 14473 Potsdam
Tel. 0331 - 288 - 1040,
Fax: 0331 - 288 - 1044,
e-mail:ossing@gfz-potsdam.de
contact: Franz J. Ossing
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