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| Nuna (supercontinent) | |
|---|---|
| Name | Nuna |
| Type | Supercontinent |
| Era | Paleoproterozoic–Mesoproterozoic |
| Alternative names | Columbia |
| Formation | ~1.8–1.6 Ga |
| Breakup | ~1.3–1.0 Ga |
Nuna (supercontinent) was an early Proterozoic supercontinent assembled during the Paleoproterozoic and persisted into the Mesoproterozoic, playing a pivotal role in Precambrian tectonics, paleogeography, and the evolution of Earth's surface environments. Its reconstruction links rocks, orogenic belts, and cratons across what are now North America, South America, Africa, Australia, Antarctica, Eurasia, and other fragments, informing interpretations of Paleoproterozoic geodynamics, atmospheric change, and early life. Research on Nuna integrates data from field studies, laboratory geochronology, paleomagnetism, and plate reconstructions led by institutions and researchers across United States Geological Survey, Geological Survey of Canada, Geoscience Australia, and numerous universities.
The name derives from Indigenous terms and was formalized alongside alternative labels such as Columbia during debates in the Geological Society of America and at meetings of the International Union of Geological Sciences. Early usage appears in publications by scholars associated with the Geological Society of America Bulletin and the Precambrian Research community, with competing nomenclature discussed at conferences hosted by organizations like the American Geophysical Union and the European Geosciences Union. Key proponents included researchers affiliated with the Smithsonian Institution, Curtin University, University of California, Berkeley, and the Australian National University, who compared cratonic correlations and orogenic histories to justify the preferred term.
Nuna's assembly involved collisions and suturing of Archean and Paleoproterozoic cratons during orogenies such as the Trans-Hudson orogen, Sveconorwegian orogeny, Grenville orogeny (in its early stages), and the Mawson Continent-related events. Cratons implicated include the Siberian Craton, North China Craton, West African Craton, Amazonian Craton, Laurentia, Baltica, Yilgarn Craton, and the Kaapvaal Craton. The timing of amalgamation is constrained by high-precision dates from laboratories like Lamont–Doherty Earth Observatory, Geological Survey of Canada geochronology facilities, and isotope laboratories at ETH Zurich and University of Melbourne, which used methods developed by pioneers such as Allan Cox and W. A. McDonough.
Reconstructions place orogenic belts like the Trans-Hudson orogen adjacent to cratons such as Laurentia and Amazonia, while the Snowball Earth hypotheses interact with Nuna reconstructions via paleolatitudinal positions derived from paleomagnetism studies. Paleogeographic maps produced by teams at Purdue University, University of Texas at Austin, and the University of Oxford juxtapose the Superior Province, Pilbara Craton, Kaapvaal Craton, and Fennoscandia within contiguous landmasses, with proposed marine basins linked to deposits studied in the Huronian Supergroup, Katanga Supergroup, and Roper Group. Interpretations reference stratigraphic correlations published in journals such as Precambrian Research, Journal of Geology, and Geology.
Tectonic models invoke mechanisms ranging from classical Wilson cycle processes as articulated by John Tuzo Wilson to plume-related rifting proposals influenced by studies at Institute of Earth Physics centers. Orogenic sutures such as the Transamazonian orogeny and the Yavapai orogeny mark assembly pulses, while subsequent intracontinental deformation links to events recorded in the Grenville Province and Laxfordian orogeny. Plate reconstructions incorporate datasets from researchers at Columbia University, University of Buenos Aires, and University of Copenhagen combining structural geology, metamorphic petrology, and basin analysis exemplified by studies on the Sao Francisco Craton and West Gondwana precursors.
Paleomagnetic poles from cratons such as Laurentia, Amazonia, and Baltica provide paleolatitude constraints using techniques refined by teams at Scripps Institution of Oceanography and Macquarie University. Geochronological anchors rely on U-Pb zircon ages from laboratories at Arizona State University, University of California, Los Angeles, and Tohoku University, while Hf isotopes and Lu-Hf systematics from Massachusetts Institute of Technology and University of Toronto labs inform crustal evolution. Stratigraphic correlations use type sections in the Huronian Supergroup, Vindhyan Basin, and McArthur Basin and employ chemostratigraphy and detrital zircon provenance studies published by researchers at University of Kansas and University of Melbourne.
Nuna's configuration influenced atmospheric oxygenation episodes captured in the Great Oxidation Event records and in sulfur isotope anomalies studied in cores archived by the British Geological Survey and Geological Survey of India. Paleoclimatic implications link to glaciations evidenced in the Huronian glaciation and to sedimentary archives in the Transvaal Supergroup and Jiangnan Orogen, affecting early biosphere development including stromatolite communities recorded in the Pilbara craton and microbial mat ecosystems examined by researchers at University of Queensland and Australian National University.
Nuna's breakup between roughly 1.3 and 1.0 Ga led to reorganization culminating in later supercontinents such as Rodinia and ultimately Pannotia and Pangea, with rifted margins recorded in successions like the Koolyanobbing Basin and Keweenawan Rift. Legacy features include preserved orogenic belts that influenced later assembly events studied by teams at Yale University, University of Cambridge, and University of Cape Town, and the distribution of mineral deposits in provinces like the Superior Province and Slave Craton that continues to guide economic geology practiced by agencies such as the U.S. Geological Survey and industry partners.
Category:Supercontinents