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.
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TL;DR: The South Sandwich volcanic arc system originated in Neogene westward-directed subduction beneath oceanic crust formed between South America and Antarctica and serves as an excellent tectonic laboratory as mentioned in this paper.
Abstract: The Scotia arc is the eastward-closing loop of mountains and locally emergent submarine ridges extending from the southernmost Andes through the active South Sandwich volcanic arc to the Antarctic Peninsula. Its origins lie in the Jurassic initial fragmentation of Gondwana. This fragmentation involved extreme intercratonic extension, Pacificward translation of rotating crustal blocks, and an ignimbrite flare-up. Relative motion between South America, Africa, and East Antarctica during the opening of the southern ocean basins resulted in mid-Cretaceous uplift of the Pacific margin cordillera and translation of elevated crustal blocks eastward to form the North and South Scotia Ridges. The South Sandwich volcanic arc system originated in Neogene westward-directed subduction beneath oceanic crust formed between South America and Antarctica and serves as an excellent tectonic laboratory. The physiography of the entire Scotia arc region has profoundly influenced the onset and development of the Antarctic Circu...
140 citations
TL;DR: In this paper, an integrated investigation involving U-Pb dating of igneous and detrital zircon, geochemical analysis of igniferous rocks, compositional analysis of sedimentary strata, and a synthesis of existing work across the Qilian Shan, Qaidam Basin, and the Eastern Kunlun Range of central and northern Tibet was conducted.
Abstract: In order to better constrain the evolution of the Tethyan orogenic system, we conducted an integrated investigation involving U-Pb dating of igneous and detrital zircon, geochemical analysis of igneous rocks, compositional analysis of sedimentary strata, and a synthesis of existing work across the Qilian Shan, Qaidam Basin, and the Eastern Kunlun Range of central and northern Tibet. This effort reveals five stages of arc magmatism at 1005–910 Ma, 790–720 Ma, 580–500 Ma, 490–375 Ma, and 290–195 Ma, respectively. Arc activities were interrupted by repeated continent-continent collision followed by ocean opening along the older suture zones first created in the Neoproterozoic. This suggests that Wilson cycles have played a controlling role in constructing the southern Asian continent. The magmatic history and regional geologic constraints allow us to construct a coherent tectonic model that has the following key features. (1) The linked South Qilian suture in the west and North Qinling suture in the east formed the northern boundary of the coherent Kunlun–Qaidam–North Qinling Terrane in the early Paleozoic. (2) The Songpan-Ganzi Terrane has been the western part of the Yangtze craton since the Neoproterozoic. (3) Development of the wide (>700 km) Permian–Triassic arc across the Kunlun-Qaidam Terrane was induced by flat subduction and rapid slab rollback, which also caused extreme extension of the Songpan-Ganzi Terrane. (4) The formation of the Anymaqen-Kunlun-Muztagh Ocean (= the Neo–Kunlun Ocean in this study) was created within Laurasia rather than being a preexisting ocean between Gondwana and Laurasia as postulated by most early studies.
140 citations
TL;DR: Basement inliers of high-grade metamorphic rocks within the eastern Colombian Andes record a Grenvillian history as mentioned in this paper, which can confirm that these domains took part in the aggregation of Rodinia.
Abstract: Basement inliers of high-grade metamorphic rocks within the eastern Colombian Andes record a Grenvillian history. Among them,
the Garzon Complex and the Dibulla, Bucaramanga and Jojoncito gneisses were studied using different geochronological methods
to produce better correlations in the context of the reconstruction of the Grenville belt and of the supercontinent of Rodinia.
The dynamic evolution of all of these units includes a final collisional event with exhumation of high-grade rocks. Such a
tectonic history bears strong similarities with the Grenville Province in Canada and seems to confirm that these domains took
part in the aggregation of Rodinia. Mesoproterozoic U-Pb zircon ages indicate heritage from magmatic protoliths, and the Sm-Nd
model ages, as well as the e Nd values, suggest derivation from an evolved continental domain, such as the Amazonian craton, with some mixing with juvenile
Neoproterozoic material. When these continental fragments are correlated with similar terrains in Mexico and the Central Andes,
a large crustal fragment is implied; very probably it made up the southern portion of the Grenville belt within Rodinia, which
was disrupted when Laurentia separated from Gondwana forming the Iapetus Ocean, leaving behind cratonic fragments that were
later accreted to the South American Platform.
139 citations
TL;DR: The development of the Early Cretaceous to Palaeogene West and Central African rift system can be related to the build-up of intraplate tensional stresses during the break up of Gondwana, which caused reactivation of pre-existing zones of lithospheric weakness as mentioned in this paper.
139 citations
01 Jul 1998
TL;DR: The Parana Basin, a vast sedimentation area during Paleozoic and Mesozoic times, holds a stratigraphic record ranging in age from late Ordovician to late Cretaceous and comprising six supersequences or unconformity-bounded units as discussed by the authors.
Abstract: The Parana Basin, a vast sedimentation area during Paleozoic and Mesozoic times, holds a stratigraphic record ranging in age from late Ordovician to late Cretaceous and comprising six supersequences or unconformity-bounded units (Milani, 1997): Rio Ivai (Ordovician-Silurian), Parana (Devonian), Gondwana I (Carboniferous-early Triassic), Gondwana II (middle-late triassic), Gondwana III (late Jurassic-early Cretaceous), and Bauru (late Cretaceous). Three of them coincide with major Paleozoic transgressive-regressive cycles, and the others are Mesozoic continental sedimentary packages with associated igneous rocks. These supersequences are the remnant record of successive phases of sediment accumulation alternating with times of erosion. The evolution of each supersequence was constrained by a particular tectonic and climatic setting. The Rio Ivai supersequence is closely associated with basin inception and its geometry suggests that deposition was to some extent controlled by normal faulting. The Parana supersequence deposited during a time of widespread marine flooding over the cratonic area of southwester Gondwana. From the deposition of the Gondwana I supersequence onward tru intracration conditions were established. Sharing Gondwana's dessication trend the Parana Basin sedimentation history culminated with extensive desertic conditions during the Jurassic. The Lower Cretaceous Serra Geral continental flood basalts are related to the initial moments of South Atlantic rifting and the upper Cretaceous Bauru continental cover ended the history of the basin. The hydrocarbon potential of the Parana Basin is related to two well defined source beds: the Devonian shales (Ponta Grossa Formation) and the upper Permian bituminous shales and limestones (Irati Formation). Sandy reservoirs can be found in the lower Devonian Furnas Formation, in the upper Carboniferous/lower Permian Iatarare Group and in the lower Permian Rio Bonito Formation. The role of intrusive bodies in the maturation of source rocks and in the trapping of hydrocarbons seems to be crucial and deserves more investigation. (author)
139 citations