Structural position of high-pressure felsic to intermediate …
At the northeastern edge of the Moldanubian Zone, a large body of felsic to intermediate granulite with relics of high-pressure mineral assemblage is exposed within medium …
Teal Gold Mine
The Teal deposit lies within a group of predominantly felsic volcanic rocks located approximately 700m west of the Abattoir Shear ultramafic contact. It is …
Granulite (felsic)
Garnet-bearing mafic and felsic granulites associated with magnetite deposits that have undergone high-pressure (HP) and ultrahigh-temperature (UHT) …
Geochronological constraints on the evolution of high-pressure felsic
A combined geochronological, geochemical, and Nd isotopic study of felsic high-pressure granulites from the Snowbird Tectonic Zone, northern Saskatchewan, Canada, has been carried out through the application of integrated electron microprobe and isotope dilution thermal ionization mass spectrometry (ID-TIMS) techniques. The terrane …
First finding of microdiamond, coesite and other UHP phases in felsic
The kyanite-bearing felsic granulites in the Kutná Hora Complex belong to a series of high-grade rocks, forming up to 20 km long bodies and massifs, that occur with granulite gneisses and migmatites in the Moldanubian zone (Fig. 1).The granulites exposed along the eastern border of the Moldanubian Zone are known as the Gföhl unit …
Granulite (felsic)
Granulite (felsic) Granulite: Granulite is a high-grade metamorphic rock in which Fe-Mg-silicates are dominantly hydroxyl-free; the presence of feldspar and the absence of primary muscovite are critical, cordierite …
High-pressure granulites from Cariré, Borborema Province, …
The felsic granulites yield a U–Pb age of 2110 Ma, while the mafic granulites yield U–Pb zircon ages of 613 and 589 Ma for the metamorphic recrystallization. Sm–Nd and Lu–Hf T DM ages for the mafic granulites are similar (1.6–1.3 Ga) and share positive values of ε Nd and ε Hf, which suggests that these mafic rocks were derived …
Gabbro-derived Granulites from the Northern Apennines …
The mafic granulites from the Northern Apennines commonly contain significant amounts of either olivine or Fe–Ti-oxide phases. On the basis of mineralogy and whole-rock major and trace element compositions, their protoliths are recognized as cumulus rocks derived from variably evolved tholeiitic liquids. Clinopyroxenes from the olivine-bearing rocks …
Geochronological Constraints on the Origin of the …
Metamorphic studies demonstrate that pelitic and felsic granulites recorded similar clockwise P-T paths, of which pelitic granulites were characterized by peak high-pressure metamorphism and post-peak near-isothermal decompression processes, with their P-T conditions constrained at 11–15 kbar/800–850 °C and 5.7–6.2 kbar/800–815 …
Felsic xenoliths in Triassic quartz-monzodiorite dykes from …
Felsic xenoliths occur locally in the Early Triassic quartz-monzodiorite dykes that crosscut the Sarhlef basin in Central Jebilet, Morocco. Irrespective of the secondary features linked to entrapment, three types of xenoliths are distinguished on the basis of textural evidence: 1) isotropic rocks of broad granitic appearance; 2) foliated samples …
Late Neoarchean and Paleoproterozoic tectonothermal and …
The Paleoproterozoic clockwise P–T–t paths with near-isothermal decompression segments and low geothermal gradients (c. 21–26 °C/km) of HP mafic and felsic granulites indicate a rapid post-collisional exhumation process after the significantly crustal thickening, and this long-term orogeny along the TNCO (c. 1.95–1.85 Ga; > 100 …
High-pressure partial melting and melt loss in felsic granulites …
Section snippets Geological setting. Numerous occurrences of garnet- and kyanite-bearing felsic granulites are associated with metasedimentary gneisses and migmatites in the Variscan orogen of Europe (e.g., O'Brien and Rötzler, 2003, Pin and Vielzeuf, 1983).In the Moldanubian zone, most granulites and migmatites are situated …
Protracted zircon geochronological record of UHT garnet-free granulites …
The K-feldspar clusters suggest an in source partial melting process while the microfilms and pools suggest an in situ partial melting process responsible for the formation of the leucocratic (felsic leucosomes) and mesocratic to melanocratic bands (granulites or residues; Figs. 3 F, 4 B, 5 A).
Quantitative P-T-X constraints on orthopyroxene-bearing …
High-pressure granulites are generally characterized by the absence of orthopyroxene. However, orthopyroxene is reported in a few high-pressure, felsic–metapelitic granulites, such as the ...
Felsic granulite with layers of eclogite facies rocks in the …
Garnet porphyroblasts from both felsic and mafic granulites reveal a well-preserved core to rim zonation of major and trace elements. Selected compositional maps and profiles of major elements and some trace elements (Y, Na, Ti, P) from both mafic and felsic granulites obtained by detailed X-ray maps are illustrated in Fig. 5, Fig. 6, Fig. 7.
High-pressure/ultrahigh-temperature mafic and felsic granulites
Garnet-bearing mafic and felsic granulites associated with magnetite deposits that have undergone high-pressure (HP) and ultrahigh-temperature (UHT) metamorphism occur in the Yangjiazhai area of ...
Metamorphic evolution of high-pressure felsic and pelitic …
Felsic granulites experienced high-pressure metamorphism up to ∼12 kbar, while pelitic granulites estimated peak pressure is 11–15 kbar. The decompression stage (M 2) is indicated by cordierite + sillimanite symplectite and/or cordierite coronae with …
High-pressure granulites of the Podolsko complex, …
The Podolsko complex, Bohemian Massif, is a mid-crustal migmatite–granite dome exposed along a tectonic boundary separating the upper crust from the deeply eroded interior of the Variscan orogen, referred to as the Moldanubian Zone. This study examines metamorphic history of mafic and felsic granulites that occur in this complex as minor …
Archean UHT metamorphism with counterclockwise P–T
Dong et al. (2018) interpreted the microgranular aggregates of Crn + Spl ± Pl between garnet and kyanite in felsic granulites from the South Altyn Tagh of West China, to be formed at 900–1000 °C, 3–4 kbar due to rapid decompression.
P-T-t evolution of Neoarchaean to Paleoproterozoic pelitic granulites …
A subduction process is supported from the M 1 to M 2 stages, which brought the sedimentary precursors to a depth. Conclusions (1) ... U Pb zircon dating results reveal the protoliths of the felsic granulites were emplaced at 2537–2503 Ma and metamorphosed at 2503–2464 Ma. This study indicates that the UHT metamorphism …
Deformation-induced, retrograde transformation of kyanite …
Detailed microstructural, microfabric and chemical analyses of felsic granulite within and around a ductile shear zone at the Plešovice quarry in the southern Bohemian Massif revealed deformation-induced, retrograde transformation of kyanite to andalusite.Although andalusite is absent outside the shear zone, its fraction among Al 2 …
Metamorphic and geochronological evolution of …
Three half-meter-wide pelitic granulite interlayers are found within mafic, intermediate, and felsic granulites in Chicheng of the Trans-North China Orogen, they help to understand the assembly of the Eastern and Western blocks of the the North China Craton (NCC). ... The P-T paths of chicheng mafic HPG present a hairpin-shape, which …
Rheology of Felsic Granulite at High Temperature …
First, the mafic granulites have water concentrations (0.16–0.28 wt% H 2 O) far more than those (0.034 wt% H 2 O) of the …
Paleoproterozoic ultrahigh-temperature metamorphism in …
The Khondalite Belt is situated in the northwestern North China Craton (NCC) and is representative of a quintessential granulite-facies metamorphic orogen (Fig. 1) and distinguished by the prevalent distribution of HT garnet-sillimanite ± spinel granulites (e.g., Li et al., 2019; Liu et al., 2012; Qiao et al., 2016), with infrequent occurrences of UHT …
Ultrahigh-temperature metamorphism of the felsic granulites …
Basic granulites in the Taipingzhai ovate-structural domain are mainly of medium-grained two-pyroxene granulites, but some samples show the over assemblages consisting of tiny vermicular ...
Kumdykolite, kokchetavite, and cristobalite crystallized in
Kumdykolite, kokchetavite, and cristobalite crystallized in nanogranites from felsic granulites, Orlica-Snieznik Dome (Bohemian Massif): Not an evidence for ultrahigh-pressure conditions
Crustal evolution of the Southern Granulite Terrane, south …
The HP mafic granulites exhibit clockwise P–T paths with a considerable heating process (ca. 150–180 °C) from the pressure-peak stage (HP-granulite sub-facies) to the temperature-peak stage (UHT-granulite sub-facies). Zircon U-Pb dating yields an age of 2513 ± 29 indicates that the metamorphism took place in the Neoarchean.
Origin of felsic granulite microstructure by heterogeneous
It shows that the precursor of the Variscan felsic granulites was a high-pressure alkali feldspar-rich coarse-grained layered orthogneiss. Its S1 subhorizontal layering is defined by the alignment of alkali feldspar porphyroclasts alternating with monomineralic bands of quartz and bands rich in plagioclase and garnet.
LASS U–Th–Pb monazite and rutile geochronology of felsic …
LASS U–Th–Pb monazite and rutile geochronology of felsic high-pressure granulites (Rhodope, N Greece): Effects of fluid, deformation and metamorphic reactions in local subsystems ... Here we explore the micro-scale record of this process using syn-kinematic monazite in two shear zones in a >20,000 km 2 terrane of exhumed lower …
Stealth Metasomatism in Granulites from Ivrea (NW Italy): …
Granulites and associated dykes from the less well-studied southern Ivrea–Verbano Zone (around Ivrea town) are characterized by combining field, macro, micro and chemical (major and trace-element mineral composition) data to identify chemical and rheological variations in the lower crust that could be relevant for geodynamic …