GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 112-4
Presentation Time: 8:50 AM


MACLEAN, John S., Geology, Southern Utah University, SC 309, 351 West University Boulevard, Cedar City, UT 84720 and SEARS, James W., Geosciences, University of Montana, Missoula, MT 59812,

The Siberia-west Laurentia reconstruction of Rodinia places Grenville foreland basin structures and sedimentary rocks near the SW corner of Laurentia against those near the SE corner of the Siberian craton, providing a strong Mesoproterozoic paleocontinental link between the cratons. Grenville structures are well exposed and documented in the Grand Canyon of Arizona, where five NE-trending, SE-side-up reverse faults with overlying NW-facing monoclines deform the Unkar Group, a clastic wedge of the Grenville foreland basin. The Unkar Group structures involve ~ 1 Ga mafic sills and flows. In the reconstruction, the Unkar Group structures parallel similar-scale reverse faults in the Sette-Daban basin of SE Siberia that similarly pass upward into monoclines. The Sette-Daban structures deform the Mayamkan Formation, a red-bed Grenvillian clastic wedge that was derived from outboard of the Siberian craton and that contains detrital zircons with a high similarity index to those of the Grenville clastic wedge of SW Laurentia. Detrital zircon age frequency distributions from Siberian rocks show a sudden and significant pulse of Grenville-age zircons as the Grenville foreland basin reached the region. Sette-Daban structures post-date ~ 1 Ga mafic sills and are overlain with angular unconformity by the Vendian (Ediacarian) Yudoma Group, which was deposited during Rodinia rifting when Grenville-age zircons were no longer able to cross the axis of the rift basin. The reconstruction presents a ~500-km wide transect of the Grenville foreland basin that evolved structurally and sedimentologically through the Grenville Orogeny and the rifting of Rodinia.