Geological Society of America

T198 Assembling Laurentia: Paleozoic Mobile Margins I

Thursday, 29 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

PANNOTIA: EVIDENCE FOR ITS EXISTENCE AND THERMAL LEGACY

Paper number: T198-3
Program: Technical Sessions
Time: 2:00 PM – 2:15 PM

Authors

Brendan Murphy Presenting Author
St. Francis Xavier University, Antigonish, NS
Sergei Pisarevsky
The Institute for Geoscience Research (TIGeR), Perth
Peir Pufahl
Queen's University, Kingston, ON
Cecilio Quesada
and Facultad de Geológicas; Universidad Complutense de Madrid, Madrid
Christopher Spencer
Queen’s University Department of Geological Sciences and Geological Engineering, Kingston, ON
Robin Strachan
Hayling Island, NH
Lei Wu
McGill University, Montréal, QC
R. Nance
Ohio University, Athens, OH
Peter A. Cawood
Monash University, Australia, Clayton, VIC
William J. Collins
The Institute for Geoscience Research (TIGeR),, Perth, WA
Wei Dan
Guangzhou Institute of Geochemistry (GIG), Guangzhou
Luc S. Doucet
The Institute for Geoscience Research (TIGeR), Perth, WA
Philip J. Heron
Durham University, Durham
Zheng-Xiang Li
The Institute for Geoscience Research (TIGeR), Perth, WA
Ross Mitchell
Institute of Geology and Geophysics, Beijing

Abstract

The status of Pannotia as an Ediacaran supercontinent, or even its mere existence as a coherent large landmass, is controversial. The effect of its hypothesized amalgamation is generally ignored in mantle convection models claiming the transition from Rodinia to Pangaea represents a single supercontinent cycle. We apply three geodynamic scenarios to Pannotia amalgamation that are tested using regional geology. Scenarios involving quasi-stationary mantle convection patterns are not supported by the geological record. A scenario involving feedback between the supercontinent cycle and global mantle convection patterns predicts upwellings beneath the Gondwanan portion of Pannotia and the arrival of plumes along the entire Gondwanan (but not Laurentian) margin beginning at c. 0.6 Ga. Such a scenario is compatible with regional geology, but the candidates for plume magmatism we propose require testing by detailed geochemical and isotopic studies. If verified, this scenario could provide geodynamic explanations for the origins of the late Neoproterozoic and Early Paleozoic Iapetus and Rheic oceans and the terranes that were repeatedly detached from their margins.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-354991

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