The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In order to investigate partial melting and melt evolution during exhumation of deeply subducted continental crust, we carried out a combined study on layered leucosomes and pegmatitic veins from the Weihai-Rongcheng migmatites in the Sulu ultra-high pressure (UHP) metamorphic terrane, eastern China. The leucosomes are millimetric to centimetric in thickness and mainly consists of K-feldspar+quartz+plagioclase...
Great progress has been made in the last twenty years in understanding the unification of the North China Craton. According to a prevailing model it developed by amalgamation of four sub-blocks by three spatially and temporally separate orogenic belts: the first at ~1950Ma formed the Western Block, the second at ~1900Ma created the Eastern Block, and the third at ~1850Ma unified the Eastern and Western...
Intra-oceanic subduction has been taken as one of the most important contributors to the crustal growth of the immense Central Asian Orogenic Belt (CAOB), however, the detailed geological processes of the development and growth of numerous island arcs still remain unclear. In order to explore the development history of representative ancient island arcs, we have conducted geochronological and geochemical...
The Early Jurassic (ca. 177Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska, cross-cuts Paleozoic igneous and metasedimentary rocks of the Alexander terrane of the North American Cordillera and was emplaced during a rifting event. The complex is a circular body (~3km in diameter) of peralkaline granitic composition that has a core of arfvedsonite...
The Qalander ophiolite is a small, poorly preserved and incomplete mélange-type complex situated within the Eocene–Oligocene Walash–Naopurdan Group in the Iraqi Zagros Suture Zone (IZSZ). It is one of six fragmented ophiolite complexes emplaced in the IZSZ during the Cretaceous and Tertiary. Within the Qalander ophiolite, serpentinized dunite and harzburgite hosts small lens-shaped podiform high-Al...
Cu–Au mineralization in the Yangtze River belt is closely related to the formation of adakitic rocks. The origin of these rocks is still controversially discussed. In this study, we report zircon U–Pb ages, major-trace element and Pb–Sr–Nd isotopes of Cu–Au related adakitic rocks from the Anqing and Tongling areas of the lower Yangtze River belt (LYRB). Geochemically, the rocks show similarities to...
A detailed study on petrology and mineral chemistry of 32 mantle xenoliths has been conducted to decipher the physical and chemical characteristics of the lithosphere beneath NE Iran. Spinel lherzolite, the most abundant xenolith type, is made up of olivine, orthopyroxene, clinopyroxene, and spinel. Clinopyroxenes in the spinel lherzolites display a primitive mantle-like composition, typical of non-cratonic...
Oxygen isotopes are useful tracers of silicate melt generation processes because of the relatively constant abundance of oxygen in silicate reservoirs and the large isotopic fractionation that can occur between 18 O and 16 O during low (<350°C) and high (>350°C) temperature alteration processes at Earth's surface. Studies of oceanic island basalts (OIB) have demonstrated the...
Textural, mineralogical and geochemical data on F-rich rhyolite (ongonite) from the Ary-Bulak massif of eastern Transbaikalia help constrain the formation of magmatic topaz. In these rocks, topaz occurs as phenocrysts, thus providing compelling evidence for crystallisation at the orthomagmatic stage. Cathodoluminescence images of topaz and quartz reveal growth textures with multiple truncation events...
Heavy mineral fractions and polished thin sections from felsic granulites from the Moldanubian Zone of the Bohemian Massif were thoroughly studied by means of Raman microspectroscopy combined with optical microscopy and scanning electron microscopy. The following phases were identified, among others, as inclusions in robust minerals such as garnet and zircon: Diamond, characterized by an intense narrow...
The Gifford Creek Ferrocarbonatite Complex (GFC), located in the Neoarchean–Palaeoproterozoic Gascoyne Province, Western Australia, comprises sills, dykes, and veins of ferrocarbonatite intruding the Pimbyana Granite and Yangibana Granite of the Durlacher Supersuite and metasedimentary rocks of the Pooranoo Metamorphics. The ferrocarbonatites are associated with complex and irregularly distributed...
Active continental margins represent both sites of crustal loss by tectonic erosion, and gain by juvenile magmatism and oceanic arc–plateau accretion. Estimating the gain component depends on distinguishing between growth of margins by either accretion of oceanic crust, or juvenile magmatic addition during extension. Distinguishing between these allochthonous and autochthonous models is frequently...
The Pozantı-Karsantı ophiolite consists of a mantle unit and overlying crustal rocks. The mantle peridotite is composed of harzburgitic to dunitic rocks that are depleted in Al 2 O 3 and CaO compared to primitive mantle. The low whole-rock Al and Ca values are consistent with the high Cr# [=100×Cr/(Cr+Al)] values of spinel that range from 44 to 70. These spinels generally have low...
Mid-ocean ridge basalts (MORBs) are the most abundant magmas produced on Earth. They are widely studied to infer mantle compositions and melting processes. However, MORB liquids are also the complex end-product of a variety of intra-crustal processes such as partial or fractional crystallization, melt–rock interaction, and contamination. Deciphering the relative contribution of these different processes...
This study shows lithosphere evolution history in the west North China Craton (NCC) from the early Cretaceous to Quaternary by studying the major element, trace element and Sr–Nd–Hf isotope compositions in Jining basalts of 119.6–108.6Ma, 23.5–21.9Ma and 1.3–0.11Ma.The early Cretaceous basalts (119.6–108.6Ma) display enriched characteristics with high contents of incompatible elements, high 87...
The Dahutang deposit is a newly discovered tungsten deposit, which is within the largest ones in the world with an estimated WO 3 reserve of 2 million tones. W-mineralization is considered to be related with the Late Mesozoic granites in the district. However, the precise emplacement ages, sources of these granites, and their relationship with mineralization are not well understood. In this...
S-type peraluminous granite can crop out in various tectonic settings. The Paleozoic Piaochi granitic intrusion is a large S-type peraluminous intrusion located in the North Qinling orogen, and has important implication for its tectonic evolution. Though intensively studied, the age and tectonic setting of this intrusion are still controversial. In this study, we carried out an integrated study of...
Mafic dike–granitoid associations are common in extensional tectonic settings and provide important opportunities for understanding mantle and crust melting during the tectonic evolution of host orogenic belts. We report results of petrologic, whole rock geochemical, Sr–Nd isotopic data and in situ zircon U–Pb and Hf isotopes for a mafic dike–granitoid association from the Zhongyangchang pluton in...
The Cardigan Pluton of New Hampshire exhibits a positive correlation between peraluminosity with maficity, with as much as 8% normative corundum in rocks with 53wt.% SiO 2 . No mafic magmas of these compositions exist; the whole-rock compositions reflect high concentrations of garnet. The mafic rocks have higher CaO concentrations than garnet and require high concentrations of plagioclase...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.