Take an in depth look at the first Iturralde Crater Expedition in August 1998.

File Type: FLASH

Investigate the native Araona people who call the Bolivian rainforest home.
In perhaps the remotest and wildest part of the Bolivian lowlands, in an area hundreds of kilometers from the closest town, NASA scientists have identified what they believe to be the youngest complex meteorite impact crater on earth. Based on what is known about the geology of the region, they believe the meteorite slammed into the Earth sometime between 5,000 and 20,000 years ago, making it the youngest "large" impact crater on Earth. The crater is approximately 8 km across and is unique in that the target material was soft sediment

The crater was originally identified in the mid-1980s with satellite imagery, but a previous attempt to visit the site in 1987 was unsuccessful due to the remoteness of the locality. However, Campbell et al (1989) were able to make an excellent circumstantial case for an impact origin for the Iturralde structure based on the following observations:

o The structure is unique to the area and indeed may be unique to the Amazon basin which is devoid of geologic expression other than that of surficial Quaternary sedimentation and fluvial erosive activity

o The structure is superimposed upon the local topography

o The depth to basement is estimated to be 3 kilometers and together with tens of meters of loose Pleistocene alluvium within which the structure lies makes it very unlikely that the structure reflects any basement expression.

o The structure is > 500 Kilometers from the nearest known volcanic or karst terrain within which circular features are sometimes found

o The general form of the structure- elevated rim, annular trough, and central uplift- is that of a complex impact structure

The above were derived mostly from the interpretation of a Landsat image

In October 1998 the expedition reached the crater impact site after traveling by jet airliner, small airplane, motor boat, dugout canoe, and finally by cutting a 15 km long trail through the forest. Field data gathered during the expedition supports the hypothesis that the circular feature is a meteorite impact crater. The rings visible on the satellite image correspond to slight ridges not more than 2 m in elevation, but sufficiently higher to support upland forest vegetation, while the interior of the crater is either inundated savanna or flooded forest. However, only sophisticated methods using seismology and magnetometry can definitively prove the existence of a meteorite or meteorite fragments buried beneath hundreds of meters of alluvial deposits.

© 2002 Blue Ice International