Showing papers in "Precambrian Research in 2005"

TL;DR: In this paper, the authors proposed a model for the evolution of the North China Craton that envisages discrete Eastern and Western Blocks that developed independently during the Archean and collided along the Trans-North China Orogen during a Paleoproterozoic orogenic event.

TL;DR: In this article, a geochemical and geochronological analysis of zircon cores from the Aghbar trachytic sill and from the Bou Madine rhyolitic dome has been shown to be of Statherian age (ca. 1600-1800 Ma).

TL;DR: The Mamianshan felsic rocks were most likely generated by partial melting of the regional Paleoproterozoic Mayuan amphibolites as mentioned in this paper, with an eruption age of 818 ± 9 Ma.

TL;DR: The Mantiqueira Province (MPV) is a large, complex structural province deformed by the Neoproterozoic/Early Paleozoic Brasiliano Orogenic event in South America as discussed by the authors.

TL;DR: In this paper, the SHRIMP analyses of zircons from the volcanic rocks at the bottom of the Beiyixi Formation yield a weighted mean 206Pb/238U age of 755±-15-Ma.

TL;DR: In this article, a provenance study of Neoproterozoic siliciclastic successions in the stratigraphically and tectonically lowermost and uppermost parts of the Pan-African Gariep Belt (Stinkfontein Subgroup and Oranjemund Group, respectively) in southwestern Africa, as well as in the Rocha Group of the Punta del Este Terrane (Dom Feliciano Belt) in Uruguay, revealed that the ORANJemund and rocha groups can be correlated and most

TL;DR: A detailed account of research recently reported by as mentioned in this paper on the type and recollected material, involving optical and electron microscopy, digital image analysis and other techniques, is illustrated here, and the context for all the published materials is reevaluated.

TL;DR: In this article, detrital zircon populations in the 2.4-2.2-Ga time window are representative of the proportion of juvenile crust in their primary sources, and they yield little evidence for significant volumes of juvenile continental crust of this age.

TL;DR: The Fig Tree Group as mentioned in this paper consists of deep- to shallow-water shale, greywacke, jaspilitic banded iron formation (BIF), and carbonaceous chert.

TL;DR: In this article, a combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman Spectroscopy was used to investigate the organic structure and composition of individual Proterozoic acritarchs.

TL;DR: In this paper, the late Archean/Paleoproterozoic atmosphere prior to the rise of O 2 has been studied and it was shown that CO 2 and CH 4 were responsible for keeping the early climate warm.

TL;DR: In this article, the authors proposed a volcanic caldera setting as a likely depositional environment where jasper and siderite precipitated as alternating bands in response to episodic changes in ambient water chemistry.

TL;DR: The early Paleoproterozoic Snowy Pass Supergroup of the Medicine Bow Mountains and Sierra Madre, USA and Huronian Supergroup, Ontario, Canada were deposited along the present-day southern flank of the Wyoming and Superior cratons.

TL;DR: Babel profiles B, C, 1, 6, 7 and C image the internal architecture of the Southern and Central Finland arcs as mentioned in this paper, which can be associated with both the accretionary Svecofennian orogeny and the following Subjotnian and Jotnian rift-stages.

TL;DR: Zircon and monazite U-Pb dates, garnet Sm-Nd dates and hornblende 40 Ar/39 Ar data from the transpressional Kaoko Belt of the late Neoproterozoic Pan-African Orogenic system confirm three distinct tectono-metamorphic cycles: M1 (655-645 Ma), M2 (580-550 Ma) and M3 (535-505 Ma) as discussed by the authors.

TL;DR: The Shishkhid ophiolite is a well-preserved 13 km-thick mafic-ultramafic assemblage which comprises (from bottom to top): mantle tectonites (∼6 km), layered and isotropic gabbro(∼4.5 km), sheeted dykes (up to 0.7 km), as well as andesitic pyroclastic rocks ( ∼2 km) as mentioned in this paper.

TL;DR: In this article, an integrated sensitive high-mass resolution ion microprobe (SHRIMP) was used to detect U-Pb zircon, geochemical and Sm-Nd isotopic data from the late Archaean Gawler Craton, southern Australia, constrain major basin-forming and magmatic processes to the interval 2560-2500 ǫ.

TL;DR: Scherer et al. as discussed by the authors used U-Pb and Hf isotopic measurements on zircons from the western Superior province to confirm that the area contains at least three distinct terrane types.

TL;DR: The high-P, low-T peak metamorphic conditions of the high-grade terrain of the Barberton greenstone belt are very similar to estimates from other areas of high grade terrain and were attained during the main phase of terrain accretion in the Greenstone belt at 3230-Ma as mentioned in this paper.

TL;DR: For the late Neoproterozoic and early Cambrian (∼600 to 542 ǫ Ma), a wide range of sulphate sulphur isotope data has previously been reported.

TL;DR: In this article, the SHRIMP U-Pb zircon dates Baiyisi volcanic rocks in the Xishankou area at the northern edge of the Tarim Block, Northwest China.

TL;DR: The Strelley Pool Chert and its associated dike complex were found to be an integral part of a hydrothermal mineralogical complex in the early Archean terranes of Western Australia as discussed by the authors.

TL;DR: In this article, a U-Pb zircon geochronological study using TIMS and SHRIMP dating reveals new insights into the magmatic and metamorphic evolution of the Siberian Craton.

TL;DR: In this paper, the authors show that the deformation in the Wadi Mubarak belt can be correlated with the accepted scheme of deformation events in the Eastern Desert of Egypt and that its geometry and apparently cross-cutting orientation is controlled by a large granite complex that intruded prior to the structural evolution.

TL;DR: In this paper, high-resolution ion microprobe (SHRIMP) U-Pb zircon geochronology in the newly defined Warumpi Province of the southern Arunta Region, central Australia has identified a succession of granulite facies metasedimentary rocks (the Yaya Metamorphic Complex) that has undergone a polymetamorphic Proterozoic evolution.

TL;DR: U-Pb dating of detrital zircons from the Chiquitania and San Ignacio groups of Eastern Bolivia shows that these rocks were derived mostly from a 1765-Ma source and were deposited after 1690-Ma.

TL;DR: The Eglab massif as discussed by the authors is a metamorphic batholith composed of various juvenile calc-alkaline orogenic suites, compatible with a mature island-arc setting.

TL;DR: A felsic eruptive event within the Rio das Velhas Greenstone belt is mainly represented by volcaniclastic and resedimented volcanic-lastic rocks, besides rare lava flows of dacitic composition as mentioned in this paper.

TL;DR: The Neoproterozic Bou Azzer ophiolite, Anti-Atlas, Morocco as discussed by the authors, is one of the best preserved ophiola of Neoproglobalozic age.

TL;DR: In this article, the authors proposed a geotectonic model for the Sao Gabriel block and the eastern margin of the Rio de la Plata craton, which showed the existence of Meso/Neoproterozoic juvenile oceanic crust and island arc rocks during the Brasiliano orogenic events.