GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 165-1
Presentation Time: 9:00 AM-6:30 PM


WISE, Donald, Department of Geosciences, University of Massachusetts, Amherst, MA 01003,

Big History lacks a credible lunar origin. Despite almost universal acceptance of giant impact models, no computer simulation has duplicated isotopic composition of lunar samples nor explained recent findings of trace water. One solution may be an upgraded 1960's scenario of core-driven fission. That Big History begins during late stages of planetary accretion when grazing merger of Proto-planet Theia spun Proto-Earth almost to its stability limit. Core/mantle segregation over the next ~50 - 100 m.y. finally drove whole body fission of asymmetric blobs, Moon and Vesta, each with Earth’s primitive crust on one face and mantle on the other. Vesta escaped while Moon’s umbilical cord collapsed as the Procellarum Basin. Moon’s entrapment in close orbit allowed tidal resonance transfer of excess angular momentum to the Sun while tidal friction raised internal temperatures for a silicate atmosphere to engulf both bodies, volatiles to pass on to space, and basaltic magmas to spread new crust over both hemispheres. Doubled farside crust preserves original asymmetry with no need for a magma ocean. Escape to higher orbit ended that era at ~ 200 m.y., a zircon cooling age. Heavy bombardment for another 400 m.y, produced large basins and deep impact energy for another b.y. of mare lava flow. Subsequent slow global cooling formed minor thrust systems.

Retro-dictions test much of this scenario while radar may test its wet predictions with a sinuous rille model, substitute for a dry Moon's fatally flawed collapse of lava-tubes. Freezing regolith temperatures trap rising water vapor in shallow permafrost layers, hot volcanic gasses melt a migrating, subsurface puddle for meandering tunnel advance while melt water sinks into the regolith. The overall hypothesis produces a Moon of isotopic composition identical to Earth's mantle, explains Vesta and Moon’s first order asymmetric geology, makes Procellarum the lunar navel, and predicts lunar water in volumes beyond current dreams.

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