Asteroids and Dinosaurs and Jungles, Oh My!

From January 16 to 28, 2001, The Planetary Society invites armchair explorers worldwide to join an expedition to Belize -- via the Internet -- in search of what killed the dinosaurs. The Belize Diary will link Internet users with scientists in the field who are searching for evidence of the asteroid impact that many believe ended the age of the dinosaurs 65 million years ago.

Scientists and volunteer field workers will post daily expedition reports and images in the Belize Diary on the Society web site. They will also select daily questions to answer from those that are submitted by e-mail.

This fourth Society expedition to Belize will continue the quest to build a more complete picture of what really happened when a comet or asteroid collided with Earth off the coast of the Yucatan. The resultant Chicxulub crater is regarded by many researchers as the smoking gun for what caused dinosaurs to disappear from our planet. When that asteroid collided with Earth, it ejected millions of tons of debris into the atmosphere, ignited wildfires, generated tsunamis, and probably altered our planet's environment so that the dinosaurs, and most other living things, could not survive.

Team leaders Adriana Ocampo of NASA and Kevin Pope of Geo Eco Research will lead a group of geological adventurers into the jungles of Belize to look for further evidence of the impact. Past Society expeditions to the region have collected samples of ejecta blanket material -- debris blasted from the Chicxulub crater when the asteroid crashed just off the coast of the Yucatan. The crater, now buried under the accumulated sediment of millions of years, is 200 to 300 kilometers across (about 125 to 190 miles across).

This year's expedition has numerous scientific objectives:

• To determine how far from the point of impact debris fell in Quintana Roo, Mexico and Northern and Central Belize.
• To identify and map the distribution of material deformed by the explosion (i.e. Pook's pebbles).
• Determine the stratigraphical relationships between ejecta (debris falling from impact) deposits in Quintana Roo, Mexico and Northern and Central Belize.
• To collect samples for detailed laboratory analysis.
• To perform a survey with a magnetometer to determine the extent of ejecta blanket and look for hydrothermal deposits.
• To measure the size of cobbles and pebbles in ejecta to determine the effect of atmospheric sorting during ballistic transport.
• To look for fossils to determine the age of rocks under, over, and in the ejecta blanket.

Discoveries from previous Belize expeditions include:

• The identification of a new species of crab that went extinct at the end of the Cretaceous period, named Carcineretes planetarius in honor of the Planetary Society;
• Identification of shocked quartz in northern Belize;
• Identification in Albion in northern Belize of an unusually high concentration of iridium at the boundary layer between the Cretateous and Tertiary periods;
• Identification of possible condensate material from the impact's vapor plume, including Pook's pebbles.
• Giant ejecta boulders 8 meters across; and
• A significant outcrop of ejecta material in Mexico, the closest of all known samples to the point of impact.

While this is the Planetary Society's fourth expedition to Belize, it is the fifth sent by the Society to study evidence of the Chicxulub impact. Another expedition went to Italy in 1996 to study core samples from that same time period.