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A comprehensive database of zircon composition in West Australian magmatic rocks reveals negative correlations between both U and Th zircon/whole rock ratio and the zircon saturation temperature, with the observed change with temperature less for U (zircon/whole rock) than for Th (zircon/whole rock) . This observation implies a systematic increase in the zircon/rock ratio with falling...
We report concentrations of hydrogen (H) in upper mantle minerals of peridotites (olivine and pyroxenes) transported by alnöitic lavas, which erupted on the southwestern border of the Ontong Java Plateau (Malaita, Solomon Islands, West Pacific). Unpolarized FTIR analyses show that olivine, orthopyroxene, and diopside contain 2–32ppm, 162–362ppm and 159–459ppm wt H 2 O, respectively. In the...
The Namche Barwa Complex exposed in the Eastern Himalayan Syntaxis, south Tibet, underwent high-pressure (HP) and high-temperature (HT) granulite-facies metamorphism and associated anatexis. The HP pelitic granulites contain garnet, kyanite, sillimanite, cordierite, biotite, quartz, plagioclase, K-feldspar, spinel, ilmenite and graphite. These minerals show composite reaction texture and varying chemical...
We present the results of a geochemical and geochronological study for Late Triassic (230‒220Ma) adakitic plutons within the Archean terrane of the eastern part of the North China Craton (NCC). These plutons show adakitic signatures with high Sr, Sr/Y, (La/Yb) N , and low Cr and Ni. The enriched Nd–Hf isotopic compositions (ε Nd (t)=−13.3 to −12.9; ε Hf (t)=−17.4 to −14.6)...
A combined study of mineral inclusions, U–Pb ages and trace elements was carried out on zircon from migmatites in the Dabie orogen. The results provide insights into multistage anatexis of ultrahigh-pressure metamorphic rocks in the continental collision orogen. Zircon grains in thin sections and mounts record four episodes of magmatic, metamorphic and anatectic events: (1) middle Neoprotrozoic U–Pb...
The Meso-Cenozoic geodynamic evolution of the Eastern Pontides Orogenic Belt, which is one of the key areas of the Alpine-Himalayan system, is still controversial due to lack of systematic geological, geophysical, geochemical and chronological data. The prevailing interpretation is that this belt represents the southern margin of Eurasia during the Mesozoic and its geodynamic evolution is related...
Impure marbles from ultra-high pressure (UHP) metamorphic belts bear significant information on the metamorphic evolution and carbon cycling during continental subduction and exhumation. In this study, detailed petrological data are presented and a P–T–X(CO 2 ) path is constructed for the impure marbles from the Dabie UHP terrane. Coesite relicts are discovered as inclusions within dolomite...
Observed geochemical and geophysical signatures in the southern Svecofennian domain (SD) and the Transscandinavian Igneous Belt (TIB) are explained through a model of tectonic cycling and episodic south-westward migration of a subduction zone system. The Västervik area is located between these two major tectonic domains and as such has received much attention. Granitoids of the Västervik area were...
In order to determine the extent and timing of dyke formation related to possible E–W extension along the southern margin of Eurasia during Early Cenozoic time, we examined ca. 30 mostly andesitic dykes intruding the Ladakh batholith from 10 to 50km west of Leh (NW India). The dykes in the east of the area trend E–NE and those in the west trend N–NW. The difference in orientation is also evident in...
Mesozoic kimberlitic magmatism was geographically widespread across central New York State, and nearly 90 distinct intrusions have been discovered since the first “serpentinite body” was described over 175years ago. Most of the intrusions are narrow (<30cm wide), near vertical, north–south oriented dikes, although three larger, irregular diatremes are also known. Previous studies assumed that all...
The Lüliang Complex is situated in the central part of the western margin of the Trans-North China Orogen (TNCO) in the North China Craton (NCC), and consists of metamorphic volcanic and sedimentary rocks and granitoid intrusions. The Yuanjiacun Formation metasediments occupy roughly the lowest part of the Lüliang Group and are mainly represented by well-bedded meta-pelites (chlorite schists and sericite–chlorite...
Abundant and widely distributed unmetamorphosed mafic dikes intrude Mesoproterozoic rocks of the New Jersey Highlands. The age of the dikes is imprecisely known but interpreted to fall between 615 and 576Ma, which is consistent with the range of ages of mafic dikes from Labrador and Nova Scotia south to Pennsylvania that were emplaced along the rifted eastern Laurentian margin. New Jersey Highlands...
Northeastern China is characterized by widespread Mesozoic volcanic rocks and Au–Cu–Mo mineral deposits with a total gold reserve of >2000t. Amongst those gold deposits, the newly discovered Sandaowanzi has a total reserve of ≥25t of Au and an average grade of 15g/t. This deposit is important because it is the first reported case of a dominantly Au(±Ag)-telluride deposit containing economically...
Petrological investigations of active volcanoes are often supported by mass balance, thermodynamic calculations and/or experiments performed at key conditions. Conversely, the compositions of mineral phases found in natural products are generally used as input data for predictive models calibrated to derive the intensive variables of the magmatic system. In order to evaluate the extent to which mineral...
Carboniferous igneous rocks constitute volumetrically minor components of Iranian crust but preserve important information about the magmatic and tectonic history of SW Asia. Ghushchi granites and gabbronorites in NW Iran comprise a bimodal magmatic suite that intruded Ediacaran–Cambrian gneiss and are good representatives of carboniferous igneous activity. Precise SIMS U–Pb zircon ages indicate that...
We present new Fe isotope data of 42 S-, I- and A-type (ferroan) granites from the Cambrian Delamerian orogen in South Australia, the Palaeozoic Lachlan Fold Belt and Western USA. Interpretation of these data, together with modelling suggests that magmatic processes do result in quite complex Fe-isotopic differentiation trends and can lead to granites with isotopically heavy iron with δ 5 ...
Abundant Jurassic bimodal igneous rocks are present in the Nanling region, southeastern China. Their relationship with the tectonic evolution of southeastern China in the Jurassic is still a matter of debate. The ~194Ma Xialan gabbroic intrusion is the oldest mafic intrusion in the Jurassic Nanling igneous belt discovered to date. The intrusion also hosts a significant Fe–Ti oxide deposit. Thus, this...
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