T117 Innovative Ideas in Tectonics of Earth and Other Planetary Bodies: a Session in Memory of An Yin (Posters)

Monday, 23 September 2024
8:00 AM - 5:30 PM
Hall D

DO ARCHEAN GREENSTONE BELTS RECORD PRE-/NON- PLATE TECTONICS?

Paper number: T117-7
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Early Earth was uniformitarian, or it was not. Here we advocate for non-uniformitarianism, first briefly recapping the relevant geology (granitoid-greenstone terranes) and then reviewing proposed pre-/non- plate tectonic models. These models range from entirely volcanic worlds which would not be out of place in a science fiction film, to systems that blur the conceptual boundary between plate and non-plate tectonics. Next, published criticism of pre-/non- plate tectonic models, both in general and with respect to the best-preserved early Archean greenstone belts, will be addressed. Finally, we will explore how the combined monotony and thickness of supracrustal rock production during ~3.55–3.22 Ga at the Barberton Greenstone Belt of southern Africa) and East Pilbara Terrane of northwestern Australia represent spatiotemporal records that appear inconsistent with the dominance of plate tectonics. The Phanerozoic (plate tectonic) Earth has displayed no capacity to create any comparable records. Furthermore, it is almost certainly significant that all other pre-3.2 Ga Archean greenstone belts – although more fragmentary and/or otherwise transformed vs. the Barberton Greenstone Belt and the East Pilbara Terrane – have protolith lithologies and primary structural relationships comparable to those at Barberton and Pilbara. The take-away message is: known Hadean to early Archean records can be non-uniquely interpreted via pre-/non-plate tectonic models. Plate tectonics is challenging to disprove thanks to its diversity of geologic settings, and arguments for post-3.22 Ga plate (or episodic subduction) tectonics are compelling. The uniformity observed in the earliest crust globally can be attributed to the dominance of pre-/non-plate tectonics, or to plate tectonics, but the latter interpretation requires an extraordinary preservation bias. ... An Yin favored outrageous hypotheses, so long as they were viable. Early Earth yet awaits its version of the 1960s revolution for ongoing tectonics, i.e., a breakthrough that permits our understandings to coalesce into theory-level knowledge. Outrageous hypotheses are needed.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-403845

© Copyright 2024 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.