ED31C-0906
Citizen Science and the Unsolved Austral-Asian Tektite Mystery

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Thomas H. S. Harris, Lockheed Martin Corporation, Arlington, VA, United States
Abstract:
A growing body of mid-Pleistocene evidence suggests a 786 ka cosmic impact (MIS 20) at an oblique angle onto the North American ice sheet may have created both the Carolina Bays on the US Eastern coastal plane, as well as the 60 billion tons of Australasian (AA) tektites that cover ¼ to ⅓ of Earth. No AA impact structure has ever been identified. ~12 ka after the AA tektite event came the Brunhes-Matuyama geomagnetic reversal, Earth’s most recent.

In 1986, Richard Muller’s paper “Geomagnetic Reversals from Impacts on the Earth” explained how a geologically rapid change of Earth’s crustal spin rate relative to the liquid core would upset its convective cellular dynamo structure, disrupting and dismantling Earth’s magnetic field.

Muller proposed an impact-induced mini ice age to transport 10 meters of low- and mid-latitude sea into ice at the poles, changing the crustal polar moment of inertia and accelerating rotation relative to the core. Muller’s impact ice age is a weak point, but oblique cosmic impacts deliver tangential impulse directly.

The Carolina Bays are a depositional formation of high purity quartz sand, angular to subangular in grain texture, covering approximately 5% of the continental US, with an estimated volume of 1600 km3 over the east coastal plain and some of Nebraska. The bays themselves are depressions in the sand layer, expressed through depositional overburden. They range from a few hundred meters to several kilometers in scale.

Carolina Bays are now characterized with LiDAR altimetry. Their alignment is systematic by latitude. They conform to 6 archetype ovoid shapes, easily derived using suborbital mechanics. This implies suborbital mechanics was a governor of their transport: the imprint is a snapshot of the emplacement process.

Suborbital Analysis using co-aligned axes of 45,000 Carolina Bays indicates the ice sheet impact region was the Georgian Bay, across Lake Huron to Michigan’s Saginaw Bay. The average downrange distance of the sand equates to an imparted velocity and a linear impulse per the mass of the sand. This linear impulse applied over Earth’s radius gives a |Δω| the same order Muller predicted would be necessary, 0.03 cm/s at the core mantle boundary.

If the AA tektite impact was oblique, what other imprinted signatures may remain detectable, and where?