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The East Sarmatian Orogen (ESO) is located along the southwestern domain of the East European Craton and occupies a key tectonic link between the Sarmatian and Volgo-Uralian domains. Here we investigate the Paleoproterozoic Novaya Melovatka pluton and its mafic-ultramafic xenoliths to gain insights into the role of interaction between intermediate–felsic crustal melt with mantle rocks as a mechanism...
The initial Nd and Hf isotope ratios of a 420Ma post-collisional dioritic-granitic batholith from the Northern Tibetan plateau define a negative trend above and orthogonal to the ԐHf(t)-ԐNd(t) terrestrial array. This uncommon trend offers an insight into the origin of the puzzling Nd-Hf isotope decoupling in the crustal rocks. On this trend, samples depleted in heavy rare earth elements (HREEs, i...
The suprasolidus behaviour of apatite and monazite is examined for an average metapelite composition using phase equilibria modelling coupled with solubility equations of these minerals. Both closed- and open-system scenarios are considered. Partial melting above the solidus requires apatite and monazite breakdown in order to saturate the anatectic melt in phosphorus and the light rare earth elements...
This paper focuses on the pre-collisional mature arc magmatism (ca. 790 Ma) recorded in orthogneisses from the Várzea do Capivarita Complex (VCC), southern Mantiqueira Province (PM), Brazil. The complex comprises ortho- and paragneisses tectonically interleaved during a transpressive high grade regime (ca. 650 Ma), possibly related to oblique collision. The VCC orthogneisses are metaluminous to peraluminous...
Southwest Japan, as an active convergent margin, is one of the world's natural laboratories to investigate magmatic and metasomatic processes associated with a long-lived subduction zone. Rocks that carry the imprints of mantle metasomatism in this region include serpentinite, jadeitite, omphacitite, albitite, and rodingite. Here we investigate rodingites, serpentinites and pyroxenites from the accretionary...
Northeast China is located in the eastern part of the Central Asian Orogenic Belt (CAOB) and was influenced by Paleo-Pacific subduction during the Mesozoic. Abundant granitoids from the late Paleozoic to early Mesozoic in NE China record this process, including the Khanka Lake granitoids, which resulted in extensive growth of continental crust in the area. However, the question of how and when the...
Apatite-group phosphates are nearly ubiquitous in carbonatites, but our understanding of these minerals is inadequate, particularly in the areas of element partitioning and petrogenetic interpretation of their compositional variation among spatially associated rocks and within individual crystals. In the present work, the mode of occurrence, and major- and trace-element chemistry of apatite (sensu...
The 176Lu–176Hf radioactive decay system has been widely used to study planetary crust–mantle differentiation. Of considerable utility in this regard is zircon, a resistant mineral that can be precisely dated by the U–Pb chronometer and record its initial Hf isotope composition due to having low Lu/Hf. Here we review zircon U–Pb age and Hf isotopic data mainly obtained over the last two decades and...
Utilizing microstructures of Cl-bearing biotite in pelitic and felsic metamorphic rocks, the timing of Cl-rich fluid infiltration is correlated with the pressure-temperature-time (P-T-t) path of upper amphibolite- to granulite-facies metamorphic rocks from Perlebandet, Sør Rondane Mountains (SRM), East Antarctica. Microstructural observation indicates that the stable Al2SiO5 polymorph changed from...
The Late Cretaceous Catalão I carbonatite complex consists of ultramafic silicate rocks, phoscorites, nelsonites and carbonatites. The latest stages of the evolution of the complex are characterized by several nelsonite (magnetite–apatite rock) and carbonatite dykes, plugs and veins crosscutting earlier alkaline rocks. The interaction between the latter and late-stage carbonatites and/or carbo-hydrothermal...
A garnet-bearing leucogranite and two country rocks from the Transamazonian Tandilia belt of the Rio de la Plata craton were studied in detail. The leucogranite contains garnet with homogeneous composition of pyr6(gros+andr)2spes5alm87. In a garnet-biotite migmatite, the core and rim compositions of garnet are pyr1.7(gros+andr)5spes5.6alm87.7 and pyr1.2(gros+andr)5.5spes6.7alm86.6, respectively. These...
The 2.5Ga metavolcanic rocks in Changyukou, Northwestern Hebei, can be classified into three groups based on major and trace elements: high-Mg basalts, tholeiitic basalts, and the calc-alkaline series (basaltic andesites-andesites and dacites-rhyolites).Both high-Mg basalts and tholeiitic basalts have negative anomalies of Nb, Zr, Ti and Heavy Rare Earth Elements (HREE) as well as enrichments of Sr,...
The core of the Santander Massif in the northern Andes of Colombia is dominated by migmatitic gneisses with a <1.71Ga protolith and was affected by continuous interactions of oceanic plates to the west and the northwestern corner of the South American continental plate. The exposed metamorphic core of the massif offers a unique opportunity to understand the tectonic evolution of northwestern South...
Understanding the rheological behavior of the Tibetan Plateau and its response to geodynamic processes requires a clear knowledge of the composition, evolution and lithological properties of the deep crust. Here we present U–Pb–Hf isotopes of zircons, bulk-rock geochemistry and mineral compositions for seven intermediate gneiss xenoliths and their host Early Mesozoic granites (205±6Ma) in the central...
The 547±7Ma old Achas intrusion (Damara orogen, Namibia) includes magnesian, metaluminous to slightly peraluminous, calcic to calc-alkalic granodiorites and ferroan, metaluminous to slightly peraluminous, calc-alkalic to alkali-calcic leucogranites. For the granodiorites, major and trace element variations show weak if any evidence for fractional crystallization whereas some leucogranites are highly...
Connecting the North China Craton to the east and the Tarim Craton to the west, the Alxa Terrane is a key place in investigating the timing of the final closure of the Paleo-Asian Ocean (PAO). New LA-ICPMS zircon U–Pb dating results reveal ca. 300–268Ma gabbros and diorites in the Bayan Nuru area in the eastern part of the Alxa Terrane. The ~300Ma gabbros show plagioclase accumulations with anorthite...
A dry mafic dyke from a continental lower-crustal shear zone in the Seiland Igneous Province (northern Norway) experienced syn-kinematic melt-rock interaction. Viscous shearing occurred at T≈800°C, P≈0.75–0.95GPa and was coeval with infiltration of felsic melt from adjacent migmatitic metapelites. The dyke has a mylonitic microstructure where porphyroclasts of orthopyroxene, clinopyroxene and plagioclase...
The change in the stability field of clinopyroxene in mid-ocean ridge basalt (MORB) as a function of pressure has been used widely as a geobarometer. Based on results from crystallization experiments using MORB-like compositions it has been suggested that MORB differentiation occurs at relatively high pressures at ultraslow- and slow-spreading ridges. However, differentiation requires the loss of...
The Ankaratra volcanic field covers an area of ~3800km2 in central Madagascar and comprises of lava flows, lava domes, scoria cones, tuff rings and maars emplaced at different ages (Miocene to Recent). The volcanic products include ultramafic-mafic (olivine-leucite nephelinite, basanite, alkali basalt, hawaiite and tholeiitic basalt), intermediate (mugearite and benmoreite) and felsic rocks (trachyphonolite,...
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