Presentation on theme: "February 2013 Expedition to the Empty Quarter Goals: 1.Reach the Wabar Crater in the middle of the Empty Quarter 2.Search for ancient arrowheads and other."— Presentation transcript:
February 2013 Expedition to the Empty Quarter Goals: 1.Reach the Wabar Crater in the middle of the Empty Quarter 2.Search for ancient arrowheads and other pointers in a dry lake bed 3.Return alive from the world’s largest sand desert (size of Utah)
Desert Wolves: George and his Saudi Exploring Partners Faisal and Jim
Reaching the Wabar Crater – youngest major meteorite site on earth. Approximately 200 years since the 250 yard-wide meteor struck Arabia. Today, sand dunes are quickly covering the impact site. Casey viewing multiple impact sites from a sand dune.
What did we find at the crater site? The USGS website explains There are three kinds of ejecta [at the Wabar Crater]: Rare, iron-nickel fragments of the original bolide. Generally these are small and usually highly oxidized when buried in the top 40 centimeters of sand; these samples are a type IIIa medium octahedrite. These were spalled off of the incoming bolide at initial contact with the sand as the reversed shock-wave reached the back of the object. When these fragments are found on the surface, they are covered by a black patina and are almost indistinguisable from the glass. In the dense ejecta field there is also black, melted slag (we call this "glass") formed by admixture at the shock front of the impacting meteorite (7-10%) and the sand that it hit (90-93%). Almost all of the incoming iron-nickel asteroid was converted to this material in a turbulent, high-temperature mixing process that probably consumed a 30-meter hemisphere of local sand beneath the largest fragment within the first two seconds after impact. There are also abundant bleached, shocked sandstone fragments (that we are informally calling "insta-rock" or impactite) formed from the sand by the pressure and heat of the impact shock wave. Typically, the black slag-like "glass" was ejected at high velocity, initially as a rapidly-expanding cone-shaped liquid "jet" forming around the edges of the contact between the asteroid and the sand, later as part of a complex process forming a huge cloud of debris that towered over the impact site. This fireball probably looked like a nuclear-detonation mushroom cloud, and may easily have reached the stratosphere. Often, slower-moving chunks of white impactite were engulfed by this molten "glass" while the latter was still in the air. When the envelopment was complete, the temperatures were so high that it was common for the impactite fragment inside to have been converted to a bubbly, white glassy pumice. Contrary to earlier reports, we do not believe that there was any bedrock involvement at the Wabar site. Most of the proximal black glassy slag was derived from "jetting" into the air during the initial contact of the Wabar object, and additional glass was distributed northwestward by prevailing winds by the fireball cloud. Glass fragment size correlates inversely with distance from the crater rims, with fist-sized chunks of lava-like material found close to the crater rims, while droplets of 2- 4 millimeters are common 850 meters northwest of the Philby "A" crater. http://volcanoes.usgs.gov/jwynn/3wabar.htm
Large piece of “impactite” and small glass “pearls” formed from molten sand cooling and dropping from the sky.
Young LDS explorers find large piece of “Impactite” The only place in the world where this mineral can be found.
Big Blue – truck breaks down near Wabar Crater. We make camp and plan to head out of the Empty Quarter short one truck.
Leaving Big Blue in the dunes, 70 miles from the nearest gravel road and hours from the nearest village.
Next stop, an ancient lake bed where we searched for flint pointers. During the Ice Age Arabia was a green land with many lakes. Hunters would hunt in the shallows of the lakes for birds, often losing the arrow and spear heads.
An example of the two dozen flint pointers we found.
Bedu road crew company who somehow retrieved “Big Blue” from the sand dunes, repaired the truck and drove it nine hours north to its home. They refused to take any money for their incredible feat of traditional Arab friendship and hospitality..