Icosahedral fracture tessellation of early Mesoproterozoic Laurentia

Authors
Citation
Jw. Sears, Icosahedral fracture tessellation of early Mesoproterozoic Laurentia, GEOLOGY, 29(4), 2001, pp. 327-330
Citations number
59
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGY
ISSN journal
0091-7613 → ACNP
Volume
29
Issue
4
Year of publication
2001
Pages
327 - 330
Database
ISI
SICI code
0091-7613(200104)29:4<327:IFTOEM>2.0.ZU;2-K
Abstract
The boundaries of the Laurentian craton conform to edges of two adjacent fa ces on a truncated icosahedral projection of Earth. The congruence of the g eology and the icosahedral tessellation has tectonic significance. It appar ently originated as a large-scale fracture pattern during the tectonically quiet early Mesoproterozoic, 100-200 m.y. after Paleoproterozoic consolidat ion of a parent supercontinent, Homogeneous stretching of the young superco ntinent across a geoid high above an insulated and thermally expanded mantl e may have induced the fractures. Neoproterozoic and Cambrian rift zones ex ploited the icosahedral fractures during breakout of Laurentia, and miogeoc lines accumulated along the margins. The Grenville and Appalachian orogenie s appear to have shortened the tessellation. Because of its high geometric symmetry, the rift tessellation may provide a reference frame for restorati on of an early Mesoproterozoic supercontinent.