Tracking Laurentia and its paleogeographic neighbors for the past 2 billion years
Abstract
The geologic and paleomagnetic record from the cratonic core of North America (Laurentia) is central to reconstructions of supercontinental assembly and breakup. It is the collisions associated with Laurentia's assembly (notably the terminal collision of the Trans-Hudson orogen) that lead to the hypothesis of a Paleoproterozoic supercontinent Nuna. The major continent-continent collision of the Grenvillian orogeny is what first led to the hypothesis of a Neoproterozoic supercontinent Rodinia. Continued additions to the paleomagnetic and geochronological database for Proterozoic Laurentia includes new Paleoproterozoic constraints I will present from the Superior Province soon after Laurentia's assembly as well as an updated compilation of rapid motion in the latest Mesoproterozoic leading up to Grenvillian orogenesis. These constraints add new perspective to the timing, configuration and plate rates associated with these paleogeographic transitions. It is very difficult to reconcile proposals of intermittent or late onset plate tectonics with the Laurentia record of plate motion, orogenesis and crustal growth. Rather, Laurentia gives us remarkable insight into plate tectonic processes across the supercontinent cycles of the past 2 billion years.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T42D..01S
- Keywords:
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- 1525 Paleomagnetism applied to tectonics: regional;
- global;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 8121 Dynamics: convection currents;
- and mantle plumes;
- TECTONOPHYSICS;
- 8157 Plate motions: past;
- TECTONOPHYSICS;
- 8178 Tectonics and magmatism;
- TECTONOPHYSICS