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- Kornprobst, Jacques, et al.
(författare)
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Boris Choubert: Unrecognized visionarygeologist, pioneer of the global tectonics.
- 2018
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Ingår i: BSGF - Earth Science Bulletin. - : EDP Sciences. - 0037-9409 .- 1777-5817. ; 189:2, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- This work is a review of Boris Choubert’s paper (1935), which was published in French under the rather devalorizing title: “Research on the Genesis of Palaeozoic and Precambrian Belts.” Despite its innovative content, this article had no impact either at the time of its publication or even later. It begins with the construction of a remarkable fit of the circum-Atlantic continents. This was based on the 1.000 meters isobath instead of the shoreline. Thirty years before Bullard et al. (1965), it demonstrated in an indisputable way the reality of the continents motion on the surface of the Earth. Therefore, Choubert designated Wegener’s “continental drift” as the main cause of tectonics. Even going beyond Wegener’s theory, he argued that this mechanism was efficient well before the formation of the Triassic Pangæa, during the whole Palaeozoic to result in the building of the Caledonian and Hercynian mountains. Although he was still encumbered by the vocabulary of the time regarding geosynclines, Boris Choubert described tectonics based on the horizontal mobility of the Precambrian continental blocks. Oddly enough, he did not apply this model to the Precambrian structures, which he attributed to the effects of the Earth’s rotation on the continental crust during its solidification. At the time of its publication, this paper was a very important step towards understanding global tectonics. Unfortunately, Choubert’s contemporaries did not generally recognize its significance.
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| 2. |
- Palkopoulou, Eleftheria, et al.
(författare)
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A comprehensive genomic history of extinct and living elephants
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 115:11, s. E2566-E2574
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Tidskriftsartikel (refereegranskat)abstract
- Elephantids are the world's most iconic megafaunal family, yet there is no comprehensive genomic assessment of their relationships. We report a total of 14 genomes, including 2 from the American mastodon, which is an extinct elephantid relative, and 12 spanning all three extant and three extinct elephantid species including an similar to 120,000-y-old straight-tusked elephant, a Columbian mammoth, and woolly mammoths. Earlier genetic studies modeled elephantid evolution via simple bifurcating trees, but here we show that interspecies hybridization has been a recurrent feature of elephantid evolution. We found that the genetic makeup of the straight-tusked elephant, previously placed as a sister group to African forest elephants based on lower coverage data, in fact comprises three major components. Most of the straight-tusked elephant's ancestry derives from a lineage related to the ancestor of African elephants while its remaining ancestry consists of a large contribution from a lineage related to forest elephants and another related to mammoths. Columbian and woolly mammoths also showed evidence of interbreeding, likely following a latitudinal cline across North America. While hybridization events have shaped elephantid history in profound ways, isolation also appears to have played an important role. Our data reveal nearly complete isolation between the ancestors of the African forest and savanna elephants for similar to 500,000 y, providing compelling justification for the conservation of forest and savanna elephants as separate species.
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| 3. |
- Kumpulainen, Risto A., et al.
(författare)
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Sweden to review its geological nomenclature
- 2017
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 139:1, s. 1-2
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Forskningsöversikt (refereegranskat)abstract
- All geoscientists working with the geology of Sweden are invited to join a common effort to review Swedish geological nomenclature and the naming of geological units and other features. A new guide, the Guide for geological nomenclature in Sweden, provides advice for this review process. The Geological Survey of Sweden will set up a new open and freely accessible database for geological names, and a dedicated name committee with mandate to formally approve proposed names will supervise the naming process. The success of this vital long-term commitment will depend on active participation of the geoscientific community at large.
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