Representative samples of high-Mg (picritic) rocks of Eocene to Oligocene age (38 to 21 Ma) from the České středohoří Mts. (CSM) in the Ohře/Eger Rift were studied and compared with Cenozoic high-Mg rocks from the Bohemian Massif. The picritic rocks of the CSM correspond to picrite, meimechite and basanite to tephrite. Individual petrographic types are characterised by the association of mafic minerals:

Natural occurrence of chrysotile, a rock-forming serpentine mineral, is largely associated with fluid-rich environments, thus making the fluid chemistry an important factor governing chrysotile growth and stability. Paper examines the effect of alkali chlorides, lowering the H2O activity in fluid, on chrysotile stability at high pressure. The behavior of natural chrysotile (Thetford) in the presence

Single crystals of SFCA-II with composition Ca2.46Fe3+8.57Fe2+0.52Al5.45O24 have been obtained from synthesis experiments in the temperature range between 1300 and 1200 °C. Diffraction experiments at ambient conditions yielded the following basic crystallographic data: space group P \( \overline{1} \), a = 10.3016(4) Å, b = 10.4656(4) Å, c = 17.9553(6) Å, α = 90.062(3), β = 89.977(3)°, γ = 109.510(3)°

We present an integrated study involving detailed field investigation, petrography, whole-rock geochemistry, Sr–Nd isotopic compositions, and zircon U–Pb–Hf isotopic compositions of Late Cretaceous granitoids and gabbroic diorites in the Shanba and Zongga plutons of the southern Lhasa subterrane, Tibet. We use the obtained data to assess the genetic relationship between the granitoids and gabbroic

The eastern Junggar Basin, controlled by continental extension (rift), was deposited by lacustrine dominated sediments during middle Permian Lucaogou period. An unusual porphyritic-like texture was observed in Lucaogou/Pingdiquan dark fine-grained organic-rich sediments in two sub-tectonic units in the basin. The “phenocrysts” are composed of two types of mineral assemblages. The first is a coarse

Several mafic-ultramafic layered intrusions were emplaced in the Fennoscandian Shield during wide-spread mantle-sourced magmatism at 2.5–2.4 Ga. The Näränkävaara intrusion (surface area 5 × 30 km2), northeastern Finland, contains a 1.5–2 km thick basal dunite (not dated), and a 1.5 km thick layered series (2436 ± 5 Ma). A newly discovered marginal series between the basal dunite and the layered series

Zircon from syenitic ejecta of Vesuvius (Campania, Italy) is unusually blue, a property shared with gem zircon from Ratanakiri province (Cambodia), which turns from natural reddish-brown to blue when heated under reducing conditions. Here, the origins of these unusual crystals were traced through geochronology, trace elements, and O-Hf isotopic compositions. The causes of its colour were investigated

A multi-methodological study was conducted in order to provide further insight into the structural and compositional complexity of rare earth element (REE) fluorcarbonates, with particular attention to their correct assignment to a mineral species. Polycrystals from La Pita Mine, Municipality de Maripí, Boyacá Department, Colombia, show syntaxic intergrowth of parisite–(Ce) with röntgenite–(Ce) and

Mesoproterozoic lamproite dykes occurring in the Banganapalle Lamproite Field of southern India show extensive hydrothermal alteration, but preserve fresh spinel, apatite and rutile in the groundmass. Spinels belong to three genetic populations. Spinels of the first population, which form crystal cores with overgrowth rims of later spinels, are Al-rich chromites derived from disaggregated mantle peridotite

Subduction of Neo-Tethys oceanic lithosphere beneath the Iranian plate during the Mesozoic formed several igneous bodies of ultramafic to intermediate and felsic composition. Intrusion of these magmas into a regional metamorphic sequence (the Sanandaj-Sirjan Zone) caused partial melting and formation of migmatites with meta-pelitic protoliths. The Alvand complex (west Iran) is a unique area comprising

Acid decomposition using concentrated H2SO4 at elevated temperature (>200 °C) is a common process to recover rare earth elements (REE) from refractory minerals where the reactions form REE sulfates, which are dissolved during a subsequent water leach. While the decomposition of REE orthophosphates and fluorocarbonates is well-documented, investigations focusing on REE silicates are more limited. The

This paper reports the discovery of columnar structures within paralavas from an active burning coal heap located in the formerly exploited coal basin of Saint-Étienne, Loire, France. The word “paralava” in this work refers to a rock that looks similar on the field to some volcanic rocks (e.g. basalts), and has been partially molten (with up to 50–60 vol% liquid). Here, the comparison between paralavas

High-Al garnet-sillimanite-graphite gneisses (khondalites) from the Matale area in central Sri Lanka show evidence for open system formation of symplectites. Three types of khondalite (type A, B, and C) were collected from two localities (Lo1 and Lo2) in this area. In Lo1, khondalite type A shows a stable mineral assemblage with garnet (Grt), ribbon quartz (Qtz), prismatic sillimanite (Sil), alkali

In the Hamadan region, Sanandaj-Sirjan Zone (SaSiZ), W Iran, a pegmatite-aplite vein occurs that contains up to 15 vol% sapphire. The Hamadan sapphire is black to blue, and translucent to opaque, which reveals its semi-gem and gem quality. On the basis of petrographic studies, the Hamadan sapphire-bearing pegmatite-aplite vein represents alkali syenitic to syenitic composition and its adjacent granitoids

Feldspars are major components of terrestrial planetary surfaces. For future space application and the setup of a comprehensive reference database, Na- and K-rich alkali feldspars, NaAlSi3O8 – KAlSi3O8, have been investigated by infrared reflectance spectroscopy. We related the feldspar spectra to the chemical composition and state of Al,Si order/disorder. The infrared measurements were analyzed with

Results of a spectroscopic and microstructural investigation of mineral grains extracted from lava-like fuel-containing materials – Chernobyl “lava” – are presented. Raman, photoluminescence and infrared spectra reveal the presence of abundant U4+, traces of Sm3+ and Cr3+ in grains of U-containing zircon and ZrO2. No oxidation of UO2 particles is observed. The ZrO2 grains consist predominantly of the

Potassic-hastingsite (IMA2018–160), ideally KCa2(Fe2+4Fe3+)(Si6Al2)O22(OH)2,was discovered in Danailingou, Inner Mongolia, China. Potassic-hastingsite is black to dark green with a vitreous luster, brittle with conchoidal fracture. The {110} cleavage is perfect and the calculated density is 3.541 g·cm−3. It is biaxial negative with α = 1.708 (2), β = 1.716 (3) and γ = 1.718 (3). Combined electron probe

Titanite from various rocks of the Karkonosze granitoid pluton (South-Eastern Poland) was studied, in order to evaluate its precision in recording magma evolution processes. The rocks are of lamprophyric, dioritic, granodioritic and granitic composition, including hybrid structures such as microgranular magmatic enclaves and composite dykes. Based on textures, chemistry and Zr-in-titanite geothermometry

Sulfur is an important element present in natural kimberlites and along with CO2, S can play a role in the kimberlite degassing. We have investigated experimentally the change in S content and CO2 solubility in synthetic kimberlitic melts in response to a range of pressure (0.5 to 2.0 GPa) and temperature (1500 to 1525 °C). Several initial S concentrations were investigated ranging from 0 to 24000

The granites and granite gneisses from a tectono-metamorphic complex exposed along the Shyok Valley in the Karakoram region, India, forms the southern margin of Asian plate in the India-Asia collision zone. These rocks have been subjected to mineralogical, geochemical, and U-Pb zircon geochronological investigations to constrain the petrogenetic and geodynamic evolution of the Karakoram terrane. Outcrop-scale

Arsenotučekite, Ni18Sb3AsS16, is a new mineral discovered in the abandoned chromium mine of Tsangli, located in the eastern portion of the Othrys ophiolite complex, central Greece. Tsangli is one of the largest chromite deposit at which chromite was mined since 1870. The Tsangli chromitite occurs as lenticular and irregular bodies. The studied chromitites are hosted in a strongly serpentinized mantle

Roterbärite, PdCuBiSe3, is a new mineral species from the Roter Bär mine, Harz Mountains, Germany. It forms euhedral to subhedral grains, up to 50 μm across, embedded in clausthalite, which is spatially associated with gold, mertieite-II, bohdanowiczite, hematite, chalcopyrite, baryte, ankerite and dolomite. Roterbärite is brittle and has a metallic luster. In plane-polarized light, roterbärite is

The Dimra Pahar Pluton is composed of arfvedsonite ± aegirine - alkali-feldspar granites with homophanous and mylonitic features. The pluton was emplaced along a regional shear zone during the post-collisional stage of the orogeny. Arfvedsonite and aegirine crystallized after alkali feldspar and quartz. The rocks are slightly peraluminous (alkali-index – AI: 0.92) to peralkaline (AI: 1.11). The pluton

Three types of amphibolites were found around a large serpentinite body in the basement of the Ohmachi Seamount in the Izu-Bonin-Mariana arc: epidote-albite amphibolite, epidote-garnet amphibolite, and garnet-zoisite amphibolite. The epidote-albite amphibolite shows a mid-ocean ridge basalt geochemical affinity based on whole-rock chemistry and Nd and Sr isotopes. The epidote-garnet amphibolite originated

The Chu Lai granite is widespread throughout the northern Kontum massif and is an important key in understanding the evolution of the Kontum region and its vicinity. The study presents new data on geochemistry, zircon U-Pb ages, and Nd-Hf isotopes from the Chu Lai granite which allows to constrain the Paleozoic tectonic evolution of the Kontum massif. The Chu Lai granite contains alumina-rich minerals

To provide new insights into the origin of garnet megacrysts and evolution of kimberlite melts, we studied in detail the polymineralic and monomineralic inclusions and their host garnets from the Grib kimberlite (Arkhangelsk diamond province, Russia). Low-Cr and high-Cr garnet megacrysts and eclogitic garnets contain abundant polymineralic and rare monomineralic inclusions. Monomineralic inclusions

Stergiouite is a new mineral from the Plaka area in the northern part of the Lavrion Mining District, Greece. The mineral occurs as clusters of stacked, platy crystals, associated with galena, sphalerite, native arsenic and sulfur. The crystals are white to colorless, with a pearly luster and white streak. No luminescence under ultraviolet (UV) radiation is observed. Stergiouite is brittle and has

The emerald mineralization in the Habachtal (Austria) is geologically and tectonically complex, and previous investigators have identified fluid inclusion evidence for a hydrothermal/metamorphic origin for the emeralds. In this paper we report the discovery of emeralds with a distinctly different inclusion population including melt inclusions, which demonstrates that at least some and probably most

The Xinxing granitic pluton is a large batholith cropping out in southern South China with its long axis parallel to the regional NE–trending faults. We conduct the first comprehensive study of zircon laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U–Pb chronology and trace element chemistry, rock-forming mineral chemistry and whole-rock element and Sr–Nd isotope geochemistry

Peraluminous orthogneisses represent a typical rock type of the Monotonous and Varied units of the Moldanubian Zone. The most probable setting for the generation of these rocks is the Cambro-Ordovician magmatic event linked to crustal anataxis, which is related to the thermal relaxation of thickened continental crust. According to their geological position, the mineralogy and geochemistry can be traced

Monchetundraite, Pd2NiTe2 is a new mineral discovered in the the Monchetundra layered intrusion, Kola Peninsula, Russia. It forms euhedral grains (up to about 20 μm) intergrown with kotulskite and pentlandite. Monchetundraite is brittle and has a metallic lustre. In plane-polarized light, monchetundraite is white to creamy pinkish white, strongly pleochroic and strongly anisotropic on prismatic sections

An airborne magnetometer survey together with field measurements of magnetic susceptibility have distinguished two main granitic suites within the eastern zone of the Brno batholith (the exposed part of the Brunovistulicum). Highly magnetic biotite-amphibole tonalites, forming widespread positive magnetic anomalies (up to 300 nT), have susceptibility (χ) regularly above 5 × 10−3. Less magnetic biotite

We report mineral compositions and bulk rock geochemistry of mafic dykes intruded in the western part of Bastar craton, comprising of Archaean Amgaon Group and Proterozoic Dongargarh Supergroup of rocks. Field relations show two distinct trends of these dykes which are almost perpendicular to each other but having similar mineralogical and geochemical characteristics. Dykes are mostly composed of pyroxenes

This paper describes specific features of isomorphism of unusual amphiboles containing up to 23 wt% ZnO and up to 1.3 wt% CuO from sulfide-free metasomatic rocks of the “Mixed Series” metamorphic complex, Pelagonian Massif, Republic of North Macedonia, in which chalcophile elements (Pb, Cu, Zn, Sb, As) occur in high concentrations in the form of oxides and oxysalts. The studied amphiboles belong to

A detailed study on petrology and mineral chemistry of 12 mantle xenoliths from Late Cretaceous basaltic lava flows at Daxizhuang has been conducted to constrain the nature and secular evolution of the Mesozoic lithospheric mantle beneath the eastern North China Craton (NCC). The Daxizhuang mantle xenoliths are mainly anhydrous spinel lherzolite, with subordinate olivine websterite and rare spinel

Yellow diamonds from the CH-7 (Chidliak) and the Misery (Ekati Mine) kimberlites in northern Canada are characterised for their nitrogen characteristics, visible light absorption, internal growth textures, and carbon isotope compositions. The diamonds are generally nitrogen-rich, with median N contents of 1230 (CH-7) and 1030 at.ppm (Misery). Normally a rare feature in natural diamonds, single substitutional

Understanding the mechanisms responsible for the interplay between mafic and felsic magmas is the key to retrieving information on their sources, and characterizing the exchange of mass between them. In order to characterize compositional and mineralogical changes in the mafic end-member during mafic-felsic magma interaction and to better understand the nature of early Paleozoic intracontinental magmatism

Polycrystalline calcite was deformed to high strain at room-temperature and confining pressures of 1–4 GPa using high-pressure torsion. The high confining pressure suppresses brittle failure and allows for shear strains >100. The post-deformation microstructures show inter- and intragranular cataclastic deformation and a high density of mechanical e\( \left\{01\overline{1}8\right\} \) twins and deformation

Geochemistry and Sr-Nd isotopes were determined in Triassic calcalkaline metalava and metapyroclastic rocks from Attica and Argolida, central Greece, to ascertain their origin, evolution, and emplacement timing. Sample protoliths were lavas, tuffs, and, subordinately, tuffites of basaltic to rhyolitic composition. Despite up to low-grade hydrothermal metamorphism, samples retain primary structures

We report olivine chemistry in basaltic rocks from the Mt. Cameroon Volcanic area, which is used as a proxy to understand mantle and early igneous processes along the ocean-continent segment of the Cameroon Volcanic Line. Most primitive olivine phenocrysts in this study have forsterite contents of 86–87.5%. Their Li concentrations are below 3.5 ppm and occur in similar concentrations in all the samples

A Ba- and Ti-rich mica (up to 14.0 wt% BaO and 13.1 wt% TiO2) occurs in nephelinites from the Middle Atlas Volcanic Province, Morocco. The rocks show a porphyritic texture composed of olivine, Ti-rich augite, nepheline and Ti-rich magnetite. Oxyphlogopite is found in secondary assemblages consisting of zeolites, clinopyroxene and Ti-oxides. This mineral occurs mostly as euhedral to subhedral crystals

The Ghorveh-Seranjic (GS) skarn is located in the northern part of the Sanandaj-Sirjan zone, NW Iran, which is part of Alpine-Himalaya orogenic belt. The GS metamorphic complex is the oldest unit in the GS area composed of marble, dolomitic marble, greenschist, and amphibolite of Early Jurassic age. The complex is intruded by NW-SE trending Late Jurassic peraluminous granitoids, which caused contact

Water solubility in Mg-endmember silicates is suggested to correlate with cation diffusivity. This study proposes a thermodynamic model by introducing the concept of transient Frenkel defect for Mg ions to quantify the relationship between water solubility and Mg diffusivity in mantle silicates. The formation of the Mg transient Frenkel defect is regarded as the escape of Mg from Mg-O polyhedron, and

The Mariana Trough, a relatively simple intra-oceanic back-arc basin, is ideal for investigating magmatic processes and mantle-crust interaction in a subduction setting. We present new major- and trace element compositions for 31 basaltic lava and glass samples from the Mariana Trough back-arc spreading center. The studied lavas include phenocrysts of plagioclase, olivine and pyroxene. Major element

We present here a new set of mineralogical and geochemical data from a cluster of east southeast-trending mafic dykes that intrude a lava flow of Sylhet traps. These tholeiitic dykes remained largely unattended in recent petrological and geochemical characterization of the Sylhet traps. This flood basalt province is believed to be a lava outpouring of Kerguelen plume active in the Northeastern India

Na-metasomatic augite and aegirine-augite episyenites are hosted by subalkaline amphibole granites in the 1.644 Ga Suomenniemi rapakivi granite complex, southeastern Finland. In an examined drill core, episyenites are bordered by up to 50-cm-wide zones of Na-enriched augite-bearing granite in which alkali feldspar forms rims on plagioclase, and aggregates of augite and magnetite have formed by fluid-induced

As a proxy of magmatic oxidation state, the accurate characterization of the Ce anomaly of zircon is of great significance since it can give important information for provenance studies of rocks as well as for exploration of intrusion-related mineral deposits. The magnitude of the zircon Ce anomaly has been traditionally described by Ce/Ce*, where Ce* is the theoretical Ce value derived from a chondrite-normalized

The microwave high-temperature irradiation was introduced to deal with the low efficiency of traditional microwave treatments for breaking granite. Structural evolution of granite between 300 °C and 800 °C was assessed through the morphology, mineral characteristics and mechanical performance. A spherical melt cavity with radial cracks formed near the biotite-rich area at 600 °C and the rock completely

In this paper, we describe the metamorphic conditions of Fe-rich granulite and variations in rare earth elements (REE) between peak garnet porphyroblasts and secondary garnet coronae. The Fe-rich granulites were collected from Vesthaugen, Sør-Rondane Mountains, East Antarctica, and consist mainly of cordierite, garnet, spinel, perthite, K-feldspar, plagioclase, and orthopyroxene or sillimanite. Temperatures

This paper aims to reveal the formation process of pitchblende by analyzing its microstructural features on the nanoscale and atomic scale. Herein, we selected pitchblende samples from drilling cores from the Miaoershan area, southern China, as the research objects. The microstructural features of pitchblende particle cores were analyzed using high-resolution transmission electron microscopy (HRTEM)

In this paper, new main and trace elements and isotopic data are presented for 14 coarse-grained eclogite xenoliths from the V. Grib kimberlite pipe in the central part of the Arkhangelsk Diamondiferous Province. Based on reconstructed whole rock MgO content, this suite is divided into high-MgO and low-MgO varieties. Eclogitic groups have a similar range of variations in the trace element compositions

Mafic-ultramafic intrusions within continental flood basalt terrains are frequently associated with Cu-Ni-PGE mineralization. This study aims to constrain the petrogenesis of early crystal phases in a promising exploration target, the Morungava mafic-ultramafic intrusion that is associated with the Paraná flood basalts. Therefore, we analyzed the composition of chromiferous spinel and associated olivine

The scheelite exploration target Messelingscharte (Eastern Tyrol, Austria) is located in vicinity of the world-class Felbertal tungsten deposit. W-(Sn) mineralisation occurs in Early Palaeozoic amphibolites (Basal Amphibolite unit) in the Tauern Window of the Eastern Alps. The most important mineralisation type is a Sn-bearing clinozoisite-scheelite skarn of pre-Alpine (Variscan?) age. It occurs as

An assemblage of tantalite-(Mn), tantalian rutile, tapiolite-(Fe), titanowodginite, ferrotitanowodginite, and hydroxycalciomicrolite occurs in the Nancy granitic pegmatite, San Luis range, Argentina. The Nancy beryl-type, beryl–columbite–phosphate subtype of LCT (Li-Cs-Ta) rare-element pegmatite was emplaced in the Paleozoic Conlara pegmatitic field. The assemblage occurs at the core margin of the

Coronae between olivine and plagioclase are a common replacement texture in mafic rocks by magmatic and metamorphic processes. Mafic dykes from Palghat Cauvery Shear Zone (PCSZ) of the granulite terrane of southern India display such multilayer coronae between olivine (Ol) and plagioclase (Pl), composed of orthopyroxene-magnetite (OM) and amphibole (Prg). Deformation twins, kinking, bending and fractures

This study investigates the paragenesis and ore mineral composition of xenotime [(Y,HREE)PO4] and florencite [LREEAl3(PO4)2(OH)6] from heavy rare earth element (HREE) deposits/prospects of the Tanami and Hall Creek regions of Western Australia. Two stages of xenotime-(Y) formation are recognized: (1) early xenotime-(Y) in breccias (breccia-hosted) and in quartz-xenotime-(Y) veins (vein-type); and (2)

The structural behaviour of maruyamaite (K-dominant tourmaline) X(K0.54Na0.28Ca0.19)Y(Mg1.3Al1.17Fe0.39Ti0.14)Z(Al5Mg)[Si5.95Al0.05O18](BO3)3V,W[O1.69(OH)2.31] from the ultrahigh-pressure metamorphic rocks of Kokchetav massif was studied using synchrotron based single-crystal diffraction up to 20 GPa. Within the whole pressure range the compression is regular and anisotropic, with the c direction being

This study presents mineralogical characterization of opaque assemblages from I- and S-type granites from the Araçuaí orogen, southeastern Brazil that belong respectively, to the pre- and syn-collisional stages of the orogeny. Although these granites are geochemically well-characterized, with a robust geochemical, isotopic and geochronological database, their opaque minerals have not yet been investigated

Complementary nano- and atomic-scale data from SEM, FIB, HRTEM, and EELS observations of after-coal impact diamonds from the giant Kara astrobleme are described, presenting their particular nano-sized porous polycrystalline structure, which consists of well-shaped single 20-30 nm nanocrystals that are free of deformation defects and do not contain lonsdaleite. The porous micro- and nanostructure is

The Huizachal–Peregrina Anticlinorium basement of the Sierra Madre Oriental in north-eastern (NE) Mexico comprises a wide variety of Precambrian and Paleozoic units. A granitic unit, described in this work as the Peregrina Tonalite (PTo), intruded the Neoproterozoic Novillo Gneiss, which is the northernmost expression of the Oaxaquia microcontinent. In contrast, the PTo’s contact with the Carboniferous