Chicxulub on EARTH Magazine

Fossil leaves reveal effect of "impact winter"

Fri, 30 Jan 2015 14:29:58 -0500

In an analysis of fossil leaves from the Cretaceous-Paleogene boundary, when the Chicxulub impact occurred, scientists saw an increase in vein density (A to B) and a decrease in leaf mass per area (C to D). Credit: B. Blonder et al., 2014, PLOS Biol. 12(9): e1001949.

When the Chicxulub bolide struck the Yucatán Peninsula at the end of the Cretaceous about 66 million years ago, widespread extinctions of land and marine animals resulted. However, the blast’s lasting effects on plants, which tend to be more resilient against impact-related fallout, have been less clear. Now, a new analysis of fossil leaves dating to around the end-Cretaceous offers some of the first quantitative evidence of a substantial shift in plant communities — toward more deciduous plants — following the impact.

Africa's impact is one that even the dinosaurs would have seen coming

Tue, 12 Aug 2014 18:37:46 -0400

An artist's rendering of an asteroid impacting Earth. Credit: NASA/Don Davis.

The crater left by the infamous Chicxulub asteroid responsible for finishing off the dinosaurs about 65 million years ago, was more than 19 kilometers deep and 177 kilometers in diameter. Those dimensions correspond to a huge energy release estimated at 100 teratons of TNT, but that’s puny compared to an impact that struck South Africa’s Barberton Greenstone Belt about 3.26 billion years ago. Now, researchers have estimated just how big that massive asteroid was and the catastrophic effect it might have had on Earth and its budding plate tectonic system.

Acid oceans followed Chicxulub impact

Fri, 08 Aug 2014 10:36:16 -0400

The proposed mechanism by which the oceans could have been acidified within days after the Chicxulub impact 65.5 million years ago. Credit: Kathleen Cantner, AGI.

Within days after the massive Chicxulub impact that ended the Cretaceous Period 65.5 million years ago, a deluge of acid rain may have turned Earth’s ocean surfaces into suddenly inhospitable homes for a multitude of microorganisms, ultimately pushing them to extinction, according to a new study.

Travels in Geology: Journeying through Cuba's geology and culture

Fri, 19 Jul 2013 11:36:04 -0400

The Moncada Formation, which lies at the Cretaceous-Paleogene boundary, is a 2-meter-thick unit that records the Chicxulub impact event. Abundant shocked quartz and a high iridium concentration lend evidence to the formation's genesis from impact events. The Cretaceous-Paleogene contact in this section is indicated by the pen. Debra Hanneman

Our geologic guide, Manuel Iturralde-Vinent, shows the contact of Late Jurassic thick-bedded limestone with overlying, thin-bedded to laminated, chert-rich Cretaceous limestone, which outcrops north of Pinar del Río, in Los Órganos near Cueva del Indio. Debra Hanneman

Tobacco is big business in Cuba. A drying barn at a Viñales Valley tobacco farm is shown here. Debra Hanneman

Traveling by bicitaxis is a fun way to see the city of Remedios. Debra Hanneman

It’s not every day that you get the chance to go to Cuba, so when I found out that the Association for Women Geoscientists (AWG) was offering an organized trip there in March 2013, I jumped at the opportunity. The excursion — nearly two weeks of exploration of our southern neighbor’s geology and culture — did not disappoint.