Final Branch Clubs & Delegates -24 Jan (Central Rift - North Rift)
Tectonomagmatic Evolution of the Midcontinent Rift
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Tectonomagmatic Tectonomagmatic Evolution of the Evolution of the Midcontinent Rift Midcontinent Rift
description
Tectonomagmatic Evolution of the Midcontinent Rift. North America (Laurentia) at 1.1 Ga. Continental Rifting- The creation of ocean basins. Mantle Plumes and Flood Basalts. Magmatic Underplating of the Crust A Consequence of Mantle Plume Magmatism. LIPs-Large Igneous Provinces. - PowerPoint PPT Presentation
Transcript of Tectonomagmatic Evolution of the Midcontinent Rift
Tectonomagmatic Evolution of the Tectonomagmatic Evolution of the Midcontinent RiftMidcontinent Rift
North America (Laurentia)at 1.1 Ga
Continental Continental Rifting-Rifting- The creation of ocean basins
Mantle Plumes and
Flood Basalts
Magmatic Underplating of the Crust
A Consequence of Mantle Plume Magmatism
LIPs-Large Igneous Provinces
Simple Tectonic Model for the
MCR
Evidence of a Starting Mantle Plume
• Rapid early rates of volcanism
• Large total volume of mafic magmatism (> 20 km volcanic edifice in central axis of rift)
• εNd of mafic rocks = 0 to slightly +
North Shore
Volcanic
Gp Portage Lake volcanics
Powdermill Group
Mamainse Pt Volcanics
Osler Group
Chengwatana volcanics
Duluth Complex
Beaver Bay Complex
NipigonSills
LoganSills
Coldwell Complex
Mellen Complex
Michipichoten Island Volcanics
Isle Royale Fault
Douglas Fault
Main IgneousMain IgneousUnits of the Units of the MCRMCR
Geophysical Evidence of Underplating
Lo-PHi-P
Primitive Ol Tholeiite
DifferentiatedDifferentiatedBasalts of the NSVGBasalts of the NSVG
Geochronology of the MCR
Hoaglund (2010)
Proposed Tectonomagmatic Model for the Midcontinent Rift
Why Didn’t the MCREvolve to an Ocean Basin?- Dissipation of the Plume- Resurgence of Grenville Compression
