@article{b509443d22f64d8b8565b51935ec4aba,
title = "Paleoarchean bedrock lithologies across the Makhonjwa Mountains of South Africa and Swaziland linked to geochemical, magnetic and tectonic data reveal early plate tectonic genes flanking subduction margins",
abstract = "The Makhonjwa Mountains, traditionally referred to as the Barberton Greenstone Belt, retain an iconic Paleoarchean archive against which numerical models of early earth geodynamics can be tested. We present new geologic and structural maps, geochemical plots, geo- and thermo-chronology, and geophysical data from seven silicic, mafic to ultramafic complexes separated by major shear systems across the southern Makhonjwa Mountains. All reveal signs of modern oceanic back-arc crust and subduction-related processes. We compare the rates of processes determined from this data and balance these against plate tectonic and plume related models. Robust rates of both horizontal and vertical tectonic processes derived from the Makhonjwa Mountain complexes are similar, well within an order of magnitude, to those encountered across modern oceanic and orogenic terrains flanking Western Pacific-like subduction zones. We conclude that plate tectonics and linked plate-boundary processes were well established by 3.2–3.6 Ga. Our work provides new constraints for modellers with rates of a {\textquoteleft}basket{\textquoteright} of processes against which to test Paleoarchean geodynamic models over a time period close to the length of the Phanerozoic.",
keywords = "Barberton Greenstone Belt, Geochemistry and geophysics, Geologic bedrock and structural maps, Onverwacht Suite, Paleoarchean, Plate tectonics",
author = "{de Wit}, Maarten and Harald Furnes and Scott MacLennan and Moctar Doucour{\'e} and Blair Schoene and Ute Weckmann and Uma Martinez and Sam Bowring",
note = "Funding Information: Field work for this MMt project was rooted in the SA Geodynamics Project, coordinated by Louis O. Nicolaysen, and funded from 1978 by the SACUGS (South African Committee for the International Union of Geological Sciences) on behalf of the CSIR (Council for scientific and Industrial Research) . After 1981, funding continued through the South African FRD (Foundation for Research and Development) and its successor, the NRF (National Research Foundation) . By 2004, NRF funding was largely met through the joint SA-German Inkaba yeAfrica program, which by 2014 had evolved into Iphakade funded through the Global Change Program of DST (Department of Science and Technology). In the 1980s and early 1990s, geochemistry and isotope analyses for this project were driven through Hugh Alsop, Bill Compston, Derek York, Don Davies and Ed Spooner, undertaken by Richard Armstrong, Rodger and Roger Hart, Marian Tredoux, Alan Wilson, Sandra Kamo and Cornel de Ronde. From 2004, geochemistry was undertaken in Bergen, Norway, funded through the Norwegian Research Council and the Meltzer Fund ( University of Bergen ). Drilling through the Noisy and Kromberg/Mendon Complexes in 2007 was enabled by funding from the Centre for Geobiology, University of Bergen. Paleomagnetic work was funded through Cor Langereis and Andrew Biggin ( University Utrech t) by the Dutch ALWNWO (Aard-en Levenswetenschappen division of the Nederlandse Organisatie voor Wetenschappelijk Onderzoek); MT work through DFG and the GFZ-Potsdam. The foundation of this work is based on field mapping, much of which was undertaken by dedicated students and postdoctoral researchers as mentioned in the text. We are grateful to Hugh Berg, Roger Hart, Hubert Staudigel, Karlis Muehlenbachs, Neil Banerjee and Tanja Zegers for help in the field. We would like to thank the local communities, farmers and mine owners for their help and generous access to, and camping on, their communal land, properties and mines, respectively; Johan Eksteen and Louis Loock of the Mpumalanga Parks Board, and Reserve Managers Property Mokoena, Jerry Myeni and S. Shoba, for access to the Songimvelo nature reserve; and Fred Daniel for his generosity in hosting many field teams in his cottage and across his {\textquoteleft}Cradle of Life{\textquoteright} game reserve. The maps were initially digitized and collated into GIS by Laura Middlemann, refined and completed by Uma Martinez ( Map 1 ) and Bastien Linol ( Map 2 ). We would like to thank anonymous reviewers for critical comments, which improved this contribution, and we express our gratitude to the editors of this volume to provide the space and opportunity to include our maps. MdW would like to dedicate this work to Roger Hart, Seal Rock, Oregon, USA, who passed away in 2011. He was an exceptionally generous person, an astute, creative scientist and ecosystem champion. Roger first explored the concepts of Archean hydrothermal processes during collaborative fieldwork in 1981 across the Makhonjwa Mountains, just after the first active black and white smokers were discovered in the Pacific Ocean; and for the next 15 years helped to apply these concepts to the rocks of the MMts. This is AEON contribution number 175 and Iphakade number 186. Publisher Copyright: {\textcopyright} 2018 China University of Geosciences (Beijing) and Peking University",
year = "2018",
month = may,
doi = "10.1016/j.gsf.2017.10.005",
language = "English (US)",
volume = "9",
pages = "603--665",
journal = "Geoscience Frontiers",
issn = "1674-9871",
publisher = "China University of Geosciences (Beijing) and Peking University",
number = "3",
}