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Chicxulub, Yucatan, Mexico

 

Chicxulub

 

During April and May 2016, DOSECC participated as part of a joint IODP-ICDP Mission Specific Platform on Expedition 364 on the L/B Myrtle in the Chicxulub Crater as part of the European Consortium for Ocean Research Drilling.  The team was tasked with drilling to 1,500 m below the bottom of the ocean to obtain the first offshore core samples from the peak ring in the central zone of the crater.  

The Chicxulub Crater is an impact crater straddling land and sea on the Mexican Yucatán Peninsula.  The estimated date of the impact which created the crater is now widely accepted as the event that triggered the mass extinction of over 70% of life on earth during the the Cretaceous–Paleogene boundary (K–Pg boundary), approximately 66 million years ago, including the global extinction of non-avian dinosaurs.

The crater itself is believed to have been created by an asteroid with an estimated diameter of 60 km, leaving a crater over 180 km in diameter and 20 km deep. After its discovery in the 1970s, it was confirmed in 1991 as an impact crater due to the discovery of shocked quartz, a gravity anomaly, and tektites in surrounding areas, including samples high in iridium. The minerals around the crater layer include limestone and marl to a depth of almost 1,000 m (3,300 ft) and date to the Paleocene era.  Underneath this layer, another 500 m of andesite glass and breccia are found.  However, within the crater, these andesitic igneous rocks were only found as shocked quartz and the K–Pg boundary is depressed to 600 to 1,100 m (average depth is about 500 m surrounding the crater).

The Chicxulub Crater is the only known crater on the planet with a remaining impact peak ring.  However, the ring is located under 600 m of sediment.  This project revealed the peak ring to be a thick layer of broken, melted rock just beneath a layer of sandstone, which may point to the possibility of an enormous tsunami triggered by the impact.

Upon the successful completion of the project, the samples were shipped to Bremen, Germany, where ECORD Science Party members will then analyze the samples to determine the formation of the peak ring and to calculate total impact energy. Samples taken reflect the post-impact conditions from the Eocene era, between 50 and 55 million years ago, and will likely reveal through the sediment and fossil record new information about how the environment and life began to recover after the cataclysm.

Read related blog posts:

Preparing for Chicxulub: Time Lapse of the Load

A Birds-Eye View of the Rig at Chicxulub, DOSECC Core Drilling Services

Chicxulub Project Watched Around the World

Chicxulub Project Report from the Yucatan

DOSECC Recognized by ESO Expedition 364 at the Chicxulub Impact Crater

DOSECC Chicxulub Project Covered on MSN

NPR Coverage of DOSECC Drilling Project in Chicxulub

Shattered Earth Making Rock Flow – ESO Expedition 364

BBC Coverage on how cores from this project are being studied