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195-3 Paired Paleomagnetic and Geochronologic Data on Igneous influenced units associated with the Paleoproterozoic Penokean Orogeny: Testing Connections between Nuna related Orogenesis and Redox Revolutions

Session: Evolution of Orogenic Belts Through Time: Insights from Sedimentation, Deformation, Magmatism, and Metamorphism (Posters)

Poster Booth No.: 189

Presenting Author:

Athena Eyster

Authors:

Eyster, Athena¹, Frank, Abigail², Brengman, Latisha Ashley³, Fu, Roger⁴, Ramezani, Jahandar⁵

(1) Tufts University, Medford, MA, USA, (2) Tufts University, Medford, MA, USA, (3) University of Minnesota Duluth, Earth and Environmental Sciences, Duluth, MN, USA, (4) Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA, (5) Massachusetts Inst Technology, EAPS, Cambridge, MA, USA,

Abstract:

Earth’s plate tectonics, including supercontinent dynamics, have been invoked throughout Earth’s evolution as key drivers of its habitability. In particular, the proposed Paleoproterozoic supercontinent Nuna and the increase in orogenesis manifested in the Penokean orogeny, involving the collision of the Superior craton and accreted arc terranes ~1.85 billion years ago, have been regarded by some as "kickstarting" modern plate tectonics preceding the "boring" or "balanced" billion. The Penokean orogeny resulted in intrusive and extrusive volcanism, accompanied by deformation and metamorphism, with some suggesting it may be a primary control on basinal subsidence, redox shifts, and iron deposition. Recent research into the kinematics of the Penokean orogeny has sparked renewed interest, leading to the development of diverse tectonic models. In contribution to this effort, we present results from ongoing paired geochronological and paleomagnetic investigations of a suite of volcanically influenced units across Minnesota, northern Michigan, and Wisconsin. The present scope of study includes units across the Superior Craton (Emperor, Clarksburg and Hemlock Volcanics, Biwabik Iron Formation, Belleview Sill) and magmatic terranes (Twelve Foot Falls Quartz Diorite and Pemene formation). Preliminary paleomagnetic data interpreted as primary extends the Paleoproterozoic APWP and facilitates a reconstruction consistent with a generally westward facing margin. Interpreted secondary remagnetizations highlight an intense period of overprinting associated with orogenesis ~1.8 Ga. Geochronological investigations reveal several units bearing euhedral zircon that are the focus of continuing work. Future work will inform paleogeographic models and allow further testing of the connections between the kinematics of Penokean orogeny, the dynamics of the supercontinent Nuna, and marine redox shifts that could be choke-points for habitability.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9545

Paired Paleomagnetic and Geochronologic Data on Igneous influenced units associated with the Paleoproterozoic Penokean Orogeny: Testing Connections between Nuna related Orogenesis and Redox Revolutions

Description

Session Format: Poster

Presentation Date: 10/21/2025

Presentation Room: HBGCC, Hall 1

Poster Booth No.: 189

Author Availability: 9:00–11:00 a.m.

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