ICOSAHEDRAL TESSELLATIONS OF EARLY MESOPROTEROZOIC LAURENTIA AND PHANEROZOIC HOTSPOTS: FUNDAMENTAL GENETIC LINK?

Icosahedral tessellation of a globe creates a precise geometric figure with 60 evenly spaced nodes at triple junctions among 12 pentagonal and 20 hexagonal plates. Five corners of the Laurentian craton, restored for Mesozoic-Cenozoic continental drift, conform to five nodes of an hexagonal cluster on an icosahedral tessellation of the Earth. Grenville and Appalachian strain appears to have displaced the sixth node of the cluster. The nodes coincide with geological regions of early Mesoproterozoic anorogenic magmatism, such as the Belt-Purcell basin, Ogilvie Mountains, north Greenland basin, Grenville anorthosite, and eastern Granite-Rhyolite Province. Fracture zones that localized early Mesoproterozoic dike swarms, sedimentary basins, and anorogenic magmatic suites link the nodes and define an icosahedral hexagon. The tessellation apparently originated during the early Mesoproterozoic tectonic quiet that fell after Paleoproterozoic consolidation of Laurentia's parent supercontinent. Neoproterozoic and/or Cambrian rift zones exploited the icosahedral fractures during breakout of Laurentia, and miogeoclines accumulated along the resulting Greenland-Caledonide, Innuitian, Cordilleran, Ouachita and Appalachian margins.

The distribution of Phanerozoic hotspots also approximates icosahedral tessellations of the Earth. Seventeen active hotspots conform to nodes defining two icosahedral tessellations, one for the Pacific basin, and one for the Atlantic-Indian basins. Evidently, these active hotspots originate in regions of the mantle characterized by uniform icosahedral fabric. The icosahedral tessellation may be an energy-efficient structural response to uniform dilation of a spherical shell.

The congruence of the scale and geometry of the Mesoproterozoic and Phanerozoic tessellations suggests that they may have a genetic link. The Mesoproterozoic nodes may represent breach points of mantle plumes that rose beneath the stalled supercontinent on an icosahedral grid. Because of its rigorous symmetry, the icosahedral tessellation may provide a framework for early Mesoproterozoic continental restorations.