| MEXICO
-- Located offshore of the town of Progreso lies the Chicxulub
Impact Crater, buried deep under hundreds of meters of sediment.
And in 2008 NASA is advocating that the site be declared a World
Heritage Site.
HISTORY
Some 65 million years ago, an iridium-rich asteroid at least
10 kilometers-wide struck the earth and which many suggest caused
the extinction of 45% of species on Earth, including dinosaurs.
Scientists estimate that more than 200 thousand cubic kilometers
of the earth's crust was instantly vaporized, melted, or ejected
from the crater. The impact left a stratum of iridium - an element
rare on this planet but common in asteroids and comets.
DISCOVERY
The existence of the crater was first detected during offshore
petroleum explorations in the 1950s. Mexico's federal oil company,
Petroleos Mexicanos (PEMEX), found sediment that did not correspond
with that of the surrounding area. The crater was named after
the nearby Mayan village of Chicxulub, and geologists continue
to study the area.
Estimates of its size vary according to how scientists read
the deviations in gravitational and magnetic field lines. With
a width of 200 kilometers (124, Chicxulub is not the largest
crater on Earth. That honor goes to Vredefort
in South
Africa. This crater has a width of 300 kilometers (186 miles)
and was formed two billion years ago.
DEEP IMPACT
Whether or not the meteor's impact was responsible for the
demise of the dinosaurs (first proposed in 1980 by Walter Alvarez
of the University of California at Berkeley) is argued in scientific
circles, but an obvious consequence of the impact can be found
in the nearby geography.
Scientists have described a 177-kilometer (110-mile) wide ring
of cenotes outlining the crater. The ring of fractured bedrock
strikes the coast at Celestún
and Bocas de Dzilam. These springs provide fresh water to the
lagoons and the variety of species that live in them. |
