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Lenses of ultramafic rocks occur in supracrustal high-grade gneiss in the northern Haskard Highlands, Shackleton Range, East Antarctica. Olivine-bearing garnet pyroxenite is the dominant rock type that is associated with hornblendite and subordinate spinel peridotite and amphibolite. The high-pressure (23–25kbar) garnet–olivine assemblage of the pyroxenite formed during Pan-African eclogite-facies...
Archean mafic–ultramafic melts, crystallized as layered intrusions in the upper crust and extruded as komatiitic flows, are primary probes of upper mantle chemistry. However, the message from their primary chemical composition can be compromised by different modes of contamination. Contaminants are typically cryptic in terms of their geochemical and isotopic signals but may be related to metasomatised...
Pre-thickened hot orogenic crust is often considered a necessary condition for the formation of continental metamorphic core complexes (MCCs). However, the discovery of MCCs in the Liaodong Peninsula, where the crust has a normal thickness (~35km), challenges the universality of this scenario. Therefore, we implement a series of 2-D numerical thermo-mechanical modeling experiments in which we investigate...
Zircon Hf isotope composition is widely used to trace the growth and evolution of continental crust. However, it is controversial whether the Hf isotope composition of magmatic zircons can faithfully reflect that of their sources, especially for S-type granites. In order to provide an insight into this issue, we have revisited the published Lu–Hf isotope data of zircons from well-studied migmatites...
The Aber-Ildut/North-Ouessant Variscan granitoid complex in the Armorican Massif is an example of high-K alkali-calcic zoned pluton, c. 304Ma in age. A first magmatic batch intruded through a northern EW-trending sinistral transcurrent shear zone, before injecting southwards as a huge horizontal zoned sill, with moderately peraluminous muscovite-free granitoids in the north and strongly peraluminous...
40Ar/39Ar dating of metamorphic rocks sometimes yields complicated datasets which are difficult to interpret in terms of timescales of the metamorphic cycle. Single-grain fusion and step-heating data were obtained for rocks sampled through a major thrust-sense shear zone (the Main Central Thrust) and the associated inverted metamorphic zone in the Sikkim region of the eastern Himalaya. This transect...
Our knowledge of the lithospheric mantle beneath the Central Asian Orogenic Belt is still sparse. Petrologic, major- and trace-element studies on the peridotite xenoliths from the Cenozoic volcanic fields in the Aershan area, the central part of the Great Xing'an Range, NE China, provide insights into the nature and evolution of the lithospheric mantle beneath the eastern part of the belt. According...
This study presents compositional data for a statistically significant number (n=180) of heated and quenched (recreated) carbonate melt inclusions trapped in magnetite and clinopyroxene in jacupirangite from Kerimasi volcano (Tanzania). On the basis of homogenization experiments for clinopyroxene-hosted melt inclusions and forsterite–monticellite–calcite phase relations, a range of 1000 to 900°C is...
To constrain the Permian–Early Mesozoic tectonic evolution of the eastern segment of the Paleo-Asian Ocean, we conducted zircon U–Pb dating and whole-rock geochemical analyses on six middle Permian–Middle Triassic intrusive plutons in central–eastern Jilin Province, NE China. Zircons from the six plutons display distinct oscillatory zoning and striped absorption in cathodoluminescence (CL) images,...
Located in the east section of the Central Asian orogen in northeastern China, the Xilamulun district comprises several newly discovered molybdenum deposits, primarily of porphyry type and Mesozoic ages. This district is divided by the Xilamulun fault into the southern and the northern parts. In this paper, we present new zircon U–Pb dating, trace elements and Hf isotope, and/or whole rock Sr–Nd–Pb...
The Central Anatolian Crystalline Complex (CACC) is a large continental domain exposed in central Turkey that was affected by high temperature metamorphism during the Late Cretaceous. As a result of this event, Paleozoic sediments became metamorphosed, initially under Barrovian conditions, then overprinted locally by high temperature–low pressure metamorphism, and intruded by widespread batholiths...
The Great Dyke contains the world's second largest platinum resource after the Bushveld Complex. Isotopic and trace element data from the interval straddling the contact between the Ultramafic and Mafic Sequences of the Great Dyke indicate a less enriched composition than in the Bushveld Complex (Great Dyke: Sri 0.7024–0.7028, εNd mostly −1 to +1, Ce/Sm 2–6; Bushveld: Sri 705–0.709, εNd −5 to −7,...
The Doros Complex is a relatively small (maximum 3.5km×7.5km) shallow-level, lopolithic, layered mafic intrusion in the early Cretaceous Paraná–Etendeka Large Igneous Province. The stratigraphy broadly comprises a minor, fine-grained gabbroic sill and a sequence of primitive olivine-cumulate melagabbros, with a basal chilled margin, an intermediate plagioclase-cumulate olivine gabbro, and a sequence...
Adakitic rocks are often considered as a key to deciphering the genesis of Archean TTGs and the early crustal growth. Granites from the Huichizi pluton in the North Qinling (NQ) unit have high Sr/Y and (La/Yb)N ratios similar to adakites. Their relatively high SiO2, K2O, and Na2O and very low MgO, Cr, and Ni contents are in the range of high-SiO2 adakites and early Archean TTGs and are compositionally...
Once situated between the Central Tianshan and Junggar terranes during Paleozoic time, the Junggar Ocean was a major southern branch of the Paleo-Asian Ocean. Thus, when and how it was closed are essential in understanding the final assembly of the Central Asian Orogenic Belt. However, the exact closure time of the Junggar Ocean remains unresolved due to the lack of reliable timing of collision-related...
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