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The Viseu area is located in the Central Iberian Zone of the Iberian Variscan Belt and hosts numerous post-thickening, collision-related granitoids intruded into upper and middle crustal levels. The present paper reports high precision U–Pb zircon and monazite ages for four plutons of the Viseu area: the syn-kinematic granitoids of Maceira (314±5 Ma), Casal Vasco (311±1 Ma) and Junqueira (307.8±0...
Ion-microprobe U–Pb zircon dating of lower-crust metasedimentary granulite are reported on samples from two localities in Europe in order to determine (a) how this environment recorded the Variscan and eo-Alpine events, and (b) whether the transition between the two orogenic cycles was continuous or separated by a gap. The samples come from enclaves hosted by Miocene volcanoes at Bournac in the French...
We report U–Pb zircon and baddeleyite age results for two mafic units in the Kangerlussuaq area which are part of the Paleogene East Greenland igneous province; the Kangerlussuaq macrodyke, which represents a feeder to some flood basalts, and the nearby Kærven Gabbro. Baddeleyite from the macrodyke yielded a concordant age of 54.7±0.4 (2σ)Ma and this is among the most precise age determinations from...
In the Eclogite Zone of the Tauern Window, a layer of strongly retrogressed leucocratic jadeite-bearing gneiss is intercalated between mafic kyanite-eclogites. The jadeite-gneiss consists of garnet+quartz+paragonite±phengite±zoisite+zircon+rutile+apatite+pyrite. Kyanite, jadeite or omphacite are exclusively present as inclusions in garnet. Retrogressive hydration during exhumation led to a breakdown...
Three types of zircon coexist in an unusual lower crustal xenolith from the Valle Guffari diatreme (Hyblean Plateau, Sicily): igneous Type 1 (near-euhedral, weakly zoned; Ce/Ce ⁎ >1); partially recrystallised Type 2 (ovoid, structureless; weak Ce anomaly); hydrothermal Type 3 (sugary, spongy-textured, probably related to F-rich aqueous fluids). U–Pb dating by LAM-ICPMS, supported by in...
The Huziyan basalts, occurring in the southern Hunan province, contain abundant mafic xenoliths. These xenolith and the basalt samples offer a unique opportunity to investigate the origin and nature of the lower crust beneath the inland area of the South China Block and to shed new light on the study of the early crustal evolution in the region. We carried out combined SHRIMP U–Pb geochronology and...
U–Pb spot zircon ages from metagabbros and metasediments of the Variscan lower crust in the Serre massif (southern Calabria) have been determined using LA-ICPMS and SIMS. The results, together with the literature data deriving from conventional and spot zircon ages and from Rb–Sr whole-rock isochrons, allow the geological history of the crustal block to be more tightly constrained from the Late Neoproterozoic...
The Tongbaishan area is situated at the junction between the Paleozoic North Qinling orogen and the Mesozoic South Qinling–Dabie–Sulu orogen. The area contains an important geological section for understanding the assembly of the Sino-Korean and Yangtze cratons. Two eclogite zones were recently recognized in this area. The peak metamorphic conditions are estimated to be 530–610 °C and 17–20 kbar for...
The Kozara Mountains of northern Bosnia and Hercegovina form part of the internal Dinarides and host two tectonically juxtaposed ophiolitic successions of different age. The southern part of the Kozara Mountains exposes the Western Vardar Ophiolitic Unit, which was obducted onto the Adriatic margin in the Late Jurassic. The northern part exposes a bimodal igneous succession that was thrust onto the...
Whole-rock major-trace elements and Sr–Nd isotopes, mineral chemistry, and zircon U–Pb and Lu–Hf isotope compositions are reported for I-type monzogranite and its mafic microgranular enclaves from the Triassic Mishuling granite in the Qinling orogen, central China. Zircon U–Pb dating yields an age of 212±5 Ma for the mafic enclaves and 213±3 Ma for the host monzogranite. Whole-rock major-trace elements,...
We present U–Pb zircon age determinations of two Variscan ultrapotassic plutonic rocks from the Moldanubian Zone (Bohemian Massif). Equant, multifaceted zircons without inherited cores from a two-pyroxene–biotite quartz monzonite of the Jihlava Pluton yielded a precise age of 335.12±0.57Ma, interpreted as dating magma crystallization. The majority of both tabular and prismatic grains from the amphibole–biotite...
The Permo-Triassic Qinling–Tongbai–Dabie–Sulu collision zone between the Sino-Korean and Yangtze cratons hosts a number of terranes; some of them carry evidence for ultrahigh-pressure (UHP) metamorphism. Discovery of retrograded high-pressure (HP) eclogites in the Tongbai Complex, in the middle of the orogen, brings fresh information to correlate segments of the orogen and understand dynamics of the...
The studied ultrahigh-pressure (UHP) eclogites, located in the southwestern part of the North Dabie complex zone (NDZ) in central China, represent deeply subducted mafic lower continental crust of the South China Block and display a multiple metamorphic evolution. However, the exact timing of the UHP metamorphism in the NDZ is poorly constrained, and thus impedes our understanding of the tectonic...
Bir Safsaf is one of the four Precambrian inliers of the southern Egyptian Western Desert; it is located midway between the juvenile crust of the Arabian–Nubian Shield and the Archean terranes of Gebel Kamil, near the Libyan border. Contrary to previous belief, Bir Safsaf is exclusively composed of late Pan-African granitoids, with U/Pb SHRIMP ages between 627Ma and 595Ma. The presence of pre-Pan-African...
Relict magmatic titanite was identified in the core of a few titanite grains with the overgrown rim of metamorphic titanite in UHP metagranite in the Dabie orogen. LA–ICPMS U–Pb dating gave Neoproterozoic ages for the magmatic titanite but Triassic ages for the metamorphic titanite. The magmatic and metamorphic titanites are clearly distinct by differences in petrological and geochemical compositions...
The Spanish Central System (SCS) is one of the largest granite batholiths in the European Variscan Belt. Zircons from five granitic intrusions from the eastern SCS have been separated and analysed for Hf isotopes by laser ablation MC-ICPMS, in order to evaluate the nature of granitic magma source. Two samples are cordierite-bearing S-type granites, the rest are amphibole-bearing I-type monzogranites...
A review of the geochronology, geochemistry and distribution of the 1380Ma Mashak Large Igneous Province (LIP) of the eastern margin of the East European craton indicates a potential link to a major breakup stage of the Mesoproterozoic supercontinent Columbia (Nuna), link to a major stratigraphic boundary (Lower–Middle Riphean), and economic significance for hydrocarbons and metallogeny. Specifically,...
Whole-rock geochemistry, Sr–Nd isotope and zircon U–Pb isotope data are reported for seven granitoid intrusions from the eastern Lhasa terrane. Our zircon U–Pb data exhibit three periods of magmatism: 164–125Ma, 83Ma, and 71–45Ma. Granitoids from the Middle Jurassic to Early Cretaceous (164–125Ma) display evolved Nd isotope composition, with ε Nd (t)=−8.6 to −15.5 and T 2DM =1.6 to...
The tectonic evolution of the Qinling orogen, central China, is the key to understanding the assembly of the Sino-Korean and Yangtze cratons. The Wuguan complex, between the early Paleozoic North Qinling and Mesozoic South Qinling tectonic belts, can provide important constraints on the late Paleozoic evolutionary processes in the Qinling orogen. U–Pb zircon analyses, using laser ablation-multicollector-inductively...
The almost unknown Ambohimirahavavy ring complex in the Cenozoic alkaline province of northwestern Madagascar has recently attracted considerable interest because of the discovery of important rare-metal mineralization. The complex consists of arc-shaped bodies made up of silica-under- and -oversaturated syenites and extremely evolved peralkaline granitic dykes, as well as several mafic to felsic...
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