Topic
Gondwana
About: Gondwana is a research topic. Over the lifetime, 6078 publications have been published within this topic receiving 263050 citations. The topic is also known as: Gondwanaland.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, U-Pb data reveal that during the mid-Cambrian the central part of West Gondwana was still undergoing a high-grade tectonometamorphic event corresponding to collision.
233 citations
TL;DR: It is shown that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea, and originated during the Triassic.
Abstract: Most extant genus-level radiations in gymnosperms are of Oligocene age or younger, reflecting widespread extinction during climate cooling at the Oligocene/Miocene boundary [∼23 million years ago (Ma)]. Recent biogeographic studies have revealed many instances of long-distance dispersal in gymnosperms as well as in angiosperms. Acting together, extinction and long-distance dispersal are likely to erase historical biogeographic signals. Notwithstanding this problem, we show that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea. A phylogeny was generated for 122 representatives covering all genera, using up to 10,000 nucleotides of plastid, mitochondrial, and nuclear sequence per species. Relying on 16 fossil calibration points and three molecular dating methods, we show that Cupressaceae originated during the Triassic, when Pangea was intact. Vicariance between the two subfamilies, the Laurasian Cupressoideae and the Gondwanan Callitroideae, occurred around 153 Ma (124-183 Ma), when Gondwana and Laurasia were separating. Three further intercontinental disjunctions involving the Northern and Southern Hemisphere are coincidental with or immediately followed the breakup of Pangea.
233 citations
TL;DR: Newland geology reflects four main tectonic phases: (1) early Mesozoic development of subduction-related terranes and their accretion to the Gondwana margin; (2) Cretaceous passive margin development and sea-floor spreading during the gondwana breakup; (3) foundering of an oceanic basin and the Eocene arrival of thinned Gondaline margin crust at a southwest-facing subduction zone, resulting in collisional orogenesis and obduction of an ophiolitic nappe from the northeast; and (4
Abstract: New Caledonia preserves evidence that constrains models for the tectonic evolution of the southwest Pacific region. Onland geology reflects four main tectonic phases: (1) early Mesozoic development of subduction-related terranes and their accretion to the Gondwana margin; (2) Cretaceous passive margin development and sea-floor spreading during the Gondwana breakup; (3) foundering of an oceanic basin and the Eocene arrival of thinned Gondwana margin crust at a southwest-facing subduction zone, resulting in collisional orogenesis and obduction of an ophiolitic nappe from the northeast; and (4) detachment faulting during extensional collapse, resulting in unroofing of metamorphic core complexes. The last phase explains supposedly anomalous metamorphic gradients in the northeast of the island.
231 citations
TL;DR: In this paper, an inspection of the available stratigraphic and geochronological data on sedimentary, volcanic, and plutonic units of the southern Central Andes of northern Chile and northwestern Argentina reveals a lull in magmatic and metamorphic activity lasting for ~100 m.y., from Early Silurian to early Late Carboniferous time.
Abstract: In Ordovician time, Gondwana in the area of northwestern Argentina and northern Chile had a west-facing active margin. The evolution of this margin culminated in the Ocloyic orogeny at the end of Ordovician time. This orogeny was caused by the collision of the allochthonous Arequipa-Antofalla terrane with this margin. The early Paleozoic evolution of northwestern Argentina and northern Chile contrasts markedly with the accretionary history of central Argentina and central Chile, where the Precordillera and Chilenia terranes docked in the Late Ordovician and Late Devonian periods, respectively. An inspection of the available stratigraphic and geochronological data on sedimentary, volcanic, and plutonic units of the southern Central Andes of northern Chile and northwestern Argentina reveals a lull in magmatic and metamorphic activity lasting for ~100 m.y., from Early Silurian to early Late Carboniferous time. This is interpreted as corresponding to a tectonic scenario in which the present Andean margin was a passive margin of Gondwana. This passive margin developed in response to the rifting off of a part of the Arequipa-Antofalla terrane; the present location of this block is unknown. Late Carboniferous time marks the renewed onset of subduction, initiating the Andean plate tectonic setting still prevalent today. Recently proposed models explain the Late Ordovician orogeny by the collision of Laurentia with western South America during Laurentia’s clockwise motion around South America and away from its position in the Neoproterozoic supercontinent. In its present form, this hypothesis is difficult to reconcile with the Paleozoic tectonostratigraphic evolution of the southern Central Andean region.
230 citations