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Pyrite corona nodules from the ∼2.7 Ga Kapai Slate, a thin, sulfidic carbonaceous shale horizon interbedded with basaltic lava flows in the Yilgarn Craton, Western Australia, have concentric compositional and isotopic zoning with distinctive textural differences between cores and mantles. The sieved-textured cores are enriched in highly compatible trace elements, incl. Ni, As, Ag, Te, Sb, Bi and Pb, and depleted in incompatible Mo and Tl, whereas the radiating-textured mantles are strongly depleted in compatible elements and enriched in incompatible elements, relative to the cores. A striking feature of the data is that both the compatible and incompatible elements are linearly correlated, with correlation coefficients as high as 0.99. A marked drop in the concentration of compatible elements and an increase in incompatible elements at the core-mantle boundary is attributed to a sudden change in the rate of growth of the nodules produced by eruption of the voluminous overlying Paringa Basalt. The weight of the basalt produced sudden compaction of the unconsolidated clays below resulting in upward advection of pore fluid, which thinned the boundary layer around the growing nodules, leading to a marked increase in the rate of pyrite growth. Rapid pyrite growth led to a dramatic depletion in highly compatible elements, and to a build-up in incompatible elements, in the boundary layers around the growing nodule mantles, which resulted in extreme depletion of compatible elements, and enrichment in incompatible elements in the nodule mantles, relative to the cores. The corona nodules are also isotopically zoned with cores that have higher δ34S, with small positive Δ33S values, and mantles that have lower δ34S and higher Δ33S. The increase in Δ33S towards the rims is attributed to S8 being advected to the growing mantles by upward fluid movement during sudden compaction, and the decrease in δ34S to the lighter S isotope, with its higher reactivity and diffusivity, being preferentially incorporated into the fast growing pyrite mantle. The extreme changes in the growth rates of the Kapai Slate corona pyrite nodules provide a new constraint on the partition coefficients of the trace elements between Archean ocean water and sedimentary pyrite. The compatibility of the analysed trace elements decreases in the order Bi > Te > Sb > Ag > Cu > Pb > Ni ≈ As > (Co, Zn, Se, Cd, Mn, W) > Tl > Mo, which is consistent with the order obtained from modern sedimentary pyrites by Large et al. (2014), except for the redox-sensitive elements Mn, Tl and Mo. These differences are attributed to the lower oxygen content of the Archean atmosphere and oceans.

40Ar/39Ar geochronology is one of the most important techniques for constraining the timing of basaltic events due to the paucity of suitable minerals in basalts for other geochronological techniques such as U–Pb (e.g., zircon, baddeleyite). Among a variety of materials from basaltic rocks that have been used for 40Ar/39Ar dating, plagioclase is the most important due to its common presence in basalts as a primary crystallizing phase, and its transparency so that fresh grains can be selected during sample preparation. However, plagioclase 40Ar/39Ar geochronology has often been compromised by alteration (e.g., sericitization by hydrothermal events), which, in practice, is difficult to identify using a petrographic microscope when the amount of alteration is low (e.g., We used laboratory step-heating experiments and theoretical simulations to characterize the 40Ar/39Ar age and Ca/K spectra of altered plagioclase so that 40Ar/39Ar dating results on altered samples can be identified and better interpreted. The step-heating experiments and theoretical simulations yielded consistent results, and show that with the presence of even a tiny amount of sericite (~0.01% for K-poor samples and ~0.1% for K-rich samples), the plagioclase samples yielded alteration plateau ages that are 3%–4% younger than the crystallization age. The difference between the alteration age of sericitized plagioclase and its crystallization age is primarily controlled by the time lapse between the crystallization and sericitization events, but also by the Ca/K ratios of the plagioclase. For plagioclase samples that experienced the same alteration event, the higher the Ca/K ratio is, the more sensitive the 40Ar/39Ar age is to alteration. We propose that the alteration signatures of plagioclase can be effectively identified through inspecting the 40Ar/39Ar age spectra, the Ca/K spectra, and the degassing curves. We also investigated the effect of sericitization of plagioclase microliths in basaltic groundmass and modelled the 40Ar/39Ar age and Ca/K spectra of altered groundmass samples. We validate our approach by revisiting published 40Ar/39Ar dating results for large igneous provinces, and showed that these dates should have been interpreted as alteration ages (minimum eruption ages) rather than crystallization ages. Finally, we demonstrate that with high degrees of alteration (~50% for K-poor and >70% for K-rich plagioclase samples), the age of hydrothermal alteration can be successfully dated.

We report the first zinc isotope data (expressed as δ66Zn relative to the JMC-Lyon standard) for chromian spinels (Cr-spinels) and coexisting olivines in oceanic peridotites. All spinel-olivine pairs fall on the 1:1 fractionation line in the diagram of δ66Znspinel versus δ66Znolivine, suggesting equilibrium isotope fractionation. Cr-spinels are always isotopically lighter than coexisting olivines (Δ66Znspinel-olivine = δ66Znspinel − δ66Znolivine = −0.50‰ to −0.33‰; n = 13), which is opposite to the positive Zn isotope fractionation between Al-spinel and olivine observed in cratonic peridotites. The “inverse” Zn isotope fractionation between Cr-spinel and olivine is unlikely to have been caused by low-temperature alteration of the oceanic peridotites, given the lack of correlation between Δ66Znspinel-olivine values and chemical indices of serpentinization and weathering (e.g., LOIs, MgO/SiO2). Ionic model calculation indicates that even considering that Zn occurs at both tetrahedral and octahedral sites in the crystal lattice of spinel, the magnitude of equilibrium fractionation is still inconsistent with the observed Zn isotope fractionation between Cr-spinel and olivine. We suggest a “chemical effect” in which the Zn O bond length (tetrahedral site) in spinel increases when Cr substitutes Al in octahedral site, which is corroborated by the striking negative correlation of δ66Zn with Cr# [molar Cr3+/(Cr3+ + Al)] in natural spinels. Therefore, Zn isotopic compositions of natural spinels can be highly variable depending on their chemical compositions. During magma differentiation, zinc is moderately incompatible in silicate minerals (olivine and pyroxene) but highly compatible in Cr-spinels/chromites that have Zn contents tens of times higher than those of basaltic melts. Given its light Zn isotopic composition, chromite crystallization–if any–can evidently elevate δ66Zn and lower Zn contents of the residual melts. Lunar mare basalts are typically characterized by higher δ66Zn and lower Zn contents relative to terrestrial basalts, but modelling suggests that chromite crystallization during magmatic differentiation is unlikely to account for Zn isotopic and elemental data of lunar mare basalts. Global ocean island basalts (OIBs) and some intraplate alkali basalts have systematically higher δ66Zn and higher Zn contents than those of the normal mantle-derived melts (e.g., mid-ocean ridge basalts; MORBs), which contradicts with a chromite crystallization model. Instead, such signatures can reflect recycling of surface carbonates into the Earth’s deep mantle, reinforcing the application of zinc isotopes as a tracer of deep carbonate recycling.

Bu çalışmada, farklı tür agregalardan üretilen silindirle sıkıştırılmış beton (SSB) örneklerinin özellikleri araştırılmıştır. Bağlayıcı olarak CEM I 42,5 R Portland çimentosu, dolomit, bazalt, mermer ve iki farklı tür kalker olmak üzere beş farklı agrega, doğal kum ve şebeke suyu kullanılmıştır. Agrega örnekleri üzerinde sıkışık ve gevşek birim hacim ağırlık, özgül ağırlık, su emme, Los Angeles parçalanma direnci tayini ve elek analizi deneyleri yapılmıştır. Farklı tür agregalarla yapılan karışımlarda su/çimento oranı 0,35 olarak sabit tutulmuştur. Dolomit, bazalt, mermer, iki farklı tür kalker olmak üzere beş farklı agreganın her biri 12-19 mm kırmataş II, 4-12 mm kırmataş I ve 0-4 mm kırmataş tozu olarak kullanılmıştır. Ayrıca farklı agrega ile üretilen betonların her birinde 0-4 mm boyutunda doğal kum kullanılmıştır. 7 ve 28 günlük basınç dayanımlarının belirlenmesi için 15 cm çapında ve 30 cm yüksekliğinde silindir, 28 günlük eğilme dayanımı için ise 15 cm×15 cm×75 cm boyutlarında prizmatik kiriş örnekler üretilmiştir. Eğilme dayanımı testinden önce 28 günlük prizmatik kiriş numunelerden yararlanılarak ultrases geçiş hızı ve dinamik elastisite modülü değerleri belirlenmiştir., In study, test results of roller compacted concrete (RCC) samples produced from different types of aggregates were researched. CEM I 42.5 R Portland cement, five different coarse aggregates (dolomite, basalt, marble, two different types of limestone), natural sand and tap water were used. The compact and loose bulk density, specific gravity, water absorption, Los Angeles abrasion resistance and sieve analysis tests were performed on the aggregate samples used. The water/cement ratio has been kept constant as 0.35 in mixtures produced with different types of aggregates. The RCC produced with five different aggregates: dolomite, basalt, marble and two different types of limestone, each were used as 12-19 mm crushed stone II, 4-12 mm crushed stone I and 0-4 mm crushed stone powder. In addition, 0-4 mm natural sand was used in each of the concretes produced with different aggregates. In order to determine the compressive strengths at the ages of 7 and 28 days, cylindrical specimens with 15 cm diameter and 30 cm height were used. Prismatic specimens with the dimensions of 15 cm×15 cm×75 cm were used to determine flexural strengths at the age of 28 days. Before bending test, ultrasonic pulse velocity and dynamic modulus of elasticity values were determined by using 28-day prismatic specimens.

Electronic probe, fluid inclusion homogenization temperature, Raman spectroscopy and laser ablation inductively coupled plasma mass spectrometry were utilized to identify the hydrothermal fluid-rock interactions in the second member of the Paleogene Kongdian Formation of Zaoyuan oilfield in Bohai Bay Basin (Kong 2 Member for short) of Well Z56 to find out the relationship between zeolite and hydrothermal fluid. The experimental results show that: (1) Pyrobitumen coexists with hydrothermal fluid characteristic minerals such as chlorite, barite, chalcopyrite, pyrite, natrolite and analcime in mudstone fractures. (2) The temperatures calculated from laser Raman spectrum of pyrobitumen, from the chlorite geothermometer and from measured homogenization temperature of natrolite inclusions are 324–354 °C, 124–166 °C and 89–196 °C, respectively; although vary widely, all the temperatures are obviously higher than the normal geothermal temperature. (3) The positive Eu anomaly of chlorite and barite, and the similar distribution pattern in rare earth elements between natrolite and basalt indicate they are from magmatic hydrothermal fluid. Moreover, drilling data shows that the Kong 2 Member in Well Z56 has several sets of basalt interlayers, suggesting there was geologic base of magmatic hydrothermal fluid activity. The magmatic hydrothermal fluid-rock interaction may be one of the reasons for the abnormal enrichment of zeolite in Kong 2 Member of the Cangdong Sag.

Spinel lherzolite xenoliths from Coyhaique, Chilean Patagonia, are located ~320 km from the Chile Trench and, therefore, their geochemical and isotopic compositions may record slab-derived metasomatism from current and/or earlier subduction zones. We present new mineral and whole-rock major and trace elements that are discussed together with noble gas data (He, Ne, Ar) and Sr-Nd isotopic ratios. Partial melting is recorded by negative correlations between basaltic elements vs. MgO in whole-rock and minerals. In general, silicate minerals show depleted light-rare earth element (LREE) over heavy-REE (HREE) patterns. Whole-rock compositions and clinopyroxene record variable degrees of partial melting (1–15%), which is corroborated by the Sr-Nd depleted character of the lherzolites. Cryptic metasomatism is evidenced by: 1) enriched LREE patterns in whole-rock and type-2 clinopyroxenes; 2) negative anomalies of Nb-Ta-Ti in whole-rock samples coupled with enrichment of large ion lithophile elements and chalcophile elements over high field strength elements and HREE; 3) positive correlations of Pb and U vs. La and negative correlations of Nb/Nb* and Ti/Ti* vs. La in clinopyroxene, and 4) positive anomalies of Li in all silicate minerals. Geochemical differences between whole-rocks and their mineral constituents indicate selective enrichment of the whole-rock samples due to grain-boundary components. 3He/4He ratios reported here are the first strongly radiogenic values found in the Patagonian subcontinental lithospheric mantle (SCLM; 0.20–2.52 RA). Most Ne isotopic ratios are indistinguishable from air composition with few samples showing a nucleogenic component, whereas Ar isotopic ratios are extensively affected by an atmospheric component. The correlation between 3He/4He and 4He/40Ar* corroborates the metasomatism recorded by lithophile and chalcophile elements. Therefore, we identify a heterogeneous SCLM affected by low but variable degrees of partial melting and subsequent enrichment by melts or fluids from recycled subduction-related materials in the spinel stability field (1.06–1.90 GPa and 886–1150 °C).

A detailed petrological study is presented to constrain the origin of a suite of alkali olivine basalt and hawaiite (>5 wt% MgO) lavas that were erupted in a rift zone within the western Mexican arc (Trans-Mexican Volcanic Belt), adjacent to the Sangangüey andesitic stratovolcano, together with more evolved lavas (mugearites and benmoreites; 9 wt%) SB crystallized at higher temperatures and lower melt-water contents (0–1.3 wt%) compared to high-MgO arc basalts (≤5.7 wt% H2O) erupted in the west-central Mexican arc. The Sangangüey lavas with 5–8 wt% MgO display evidence of mixing between high-MgO alkali olivine basalts and low-MgO mugearites. It is proposed that the unique composition of the mugearites (i.e., low SiO2 contents and elevated FeO and TiO2 contents) is the result of partial melting of mafic lower crust driven by the influx of high-MgO intraplate basalts under relatively hot, dry, and reduced conditions. On the basis of crystal textures and compositional zoning patterns, it is shown that both phenocryst growth and magma mixing occurred rapidly, most likely during ascent along fractures, and not slowly during prolonged storage in a crustal magma chamber.

Shergottites were derived from mantle reservoirs through various magmatic processes, recording geochemical signatures of the martian mantle. But the U-Pb isotopic system of shergottites remains obscured including the geological significance of Pb isotope composition, the role of martian Pb contamination, and other factors. Here we present in situ U-Pb and/or Pb-Pb analyses on minerals of the basaltic shergottite Northwest Africa (NWA) 8653 after detailed petrological and mineralogical studies. The aims of the project are to evaluate the formation process, the crystallization age as well as the characteristic Pb isotope composition of NWA 8653. Texture, major and trace element composition plus geochemical modeling suggest that NWA 8653 is an enriched shergottite derived from mixing of depleted (e.g., fractionated Yamato 980459) and enriched components (e.g., NWA 1068) in the mantle, instead of crustal assimilation. U-Pb and Pb-Pb isotopes of baddeleyite reveal a young crystallization age (187.6 ± 8.0 Ma). Pb isotope compositions of maskelynite, feldspathic intergrowth, and the majority of phosphate cluster near the predicted initial Pb and a 4.1 Ga isochron. For these minerals, calculations suggest that mixing of Pb from different reservoirs with μ (238U/204Pb) varying from 1.4 to 4.7 could explain the apparent 4.1 Ga isochron in young shergottites. Variable extents of mixing among mantle sources could further increase the isotopic heterogeneity of shergottites. Our results demonstrate that NWA 8653 was derived from a heterogeneous mantle source in terms of trace element and isotope composition. Mixing of Pb from different reservoirs in the mantle plays an important role in shaping Pb in minerals with negligible U. This study provides additional geochemical evidence for a highly heterogeneous martian mantle.

The Eastern Pontides Orogenic Belt (EPOB) in northeastern Turkey is a continental arc that is part of the Himalayan-Alpine orogeny. Late Cretaceous magmatism in this belt is dominated by high-K calc-alkaline, shoshonitic, and alkaline rocks that occur over an area of ~600 km (E-W) and ~200 km (N-S). We present new geochemical data (whole rock major and trace element analyses, mineral compositions, U-Pb zircon and titanite ages, zircon trace element data, and Sr-Nd-Pb isotopic analyses) for 153 samples, with compiled data for an additional 265 samples. Magmatism is diachronous across the arc. In the north, Cycle-I (92–84 Ma) commenced with tholeiitic and calc-alkaline basalts and andesites, and continued with felsic extrusive rocks. Cycle-II (84–70 Ma) includes mainly intermediate and felsic extrusive rocks. Over time,the low-K granitoids progressively give way to calc-alkaline granitoids in the north. In the south, Cycle-I (84–78 Ma) includes high-K trachyandesites, trachytes and felsic extrusive rocks. Cycle-II (78–65 Ma) comprises leucitites, trachybasalts, and other K-rich rocks. Shoshonitic granitoids in the south show ages between 80 and 65 Ma. Clinopyroxene compositions in trachyandesites and leucitites indicate initial crystallization at ~38 km depth and 1120 °C. Amphibole joins the phase assemblage at ~8 km depth and T

Research subject. Olivine of deep-seated inclusions from Late Cenozoic volcanic rocks of the Tunka valley.Materials and methods. Electron probe microanalysis of minerals with determination of calcium in olivine by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). A complex of methods of quantitative chemical analysis for determination of major oxides in rocks.Results. Deep-seated nodules from Late Cenozoic volcanic rocks in the Tunka Valley characterize the root part of the Slyudyanka metamorphic subterrane, formed during collisional accretion of the Khamar-Daban terrane to the Siberian paleocontinent in the Early Paleozoic and reactivated in the Late Cenozoic. From bulk compositions of deep-seated nodules, groups of xenoliths (restites, rocks closed to the primitive mantle composition, and metasomatites) and cognate rocks (magmatic and magmatic-metasomatic genesis) were distinguished. The polygenetic character of this assemblage is designated by variations of major and trace-element abundances in olivine. In olivine of xenoliths, forsterite (Fo) ranges from 86 to 91% under abundances of NiO – 0.2–0.5, MnO – 0.1–0.2, and CaO < 0.16 wt %. In olivine of magmatic rocks and those of mixed (magmatic-metasomatic) genesis, Fo decreases to 64% with a decrease in NiO (Ni/Mg ratio) and an increase in MnO and CaO. Magmatic olivine shows 0.16–0.21 wt % MnO and about 0.1 wt % CaO, in contrast to olivine of magmatic-metasomatic genesis, enriched in these oxides to 0.5 wt % and 0.45 wt %, respectively, with an increase in the Mn/Fe and Ca/Fe ratios. Olivine trends of the shallow polygenetic assemblage of inclusions are emphasized when compared with those of the deeper ones from volcanic rocks of the Vitim and Oka plateaus that represent a transition from the garnet to the spinel-pyroxene facies in mantle peridotites.Conclusion. Olivine compositions are indicative of the shallow origin of peridotite and pyroxenite nodules from the crust and crust–mantle transition in the root part of the Slyudyanka collision zone reactivated in the Late Cenozoic.

The petrological studies and geochemical analysis carried out on the basalts of Mandla Lobe (MB), Madhya Pradesh of eastern Deccan Volcanic Province (EDVP) to evaluate their petrogenetic and tectonic evolution. A variety of lavas such as columnar, vesicular, amygdaloidal, inflated pahoehoe flows and red bole interflow horizons around the study areas Chutka, Mandla and Jabalpur-Niwas sectors of Mandla lobe are found. These basalts are fine to medium grained porphyritic and non-porphyritic composed of calcic plagioclase (An36 Ab61 Or3 to An74 Ab25 Or1; labradorite to bytonite), clinopyroxene (Wo24–42, En30–52, Fs15–43; augite-ferroaugite), altered olivine, chlorophaeite, opaque and glass usually show a variety of intersertal (seriate, ophitic and subophitic), intergranular (porphyritic, glomeroporphyritic, poikilitic) textures indicating variable cooling histories and melt replenishment in a magma chamber. The MB samples exhibit tholeiitic trends evidenced by iron enrichment on AFM diagram. The La/Yb ratios of MB suggest relative enrichment of LREE over HREE without significant Europium anomalies. Low HREE ratios such as (Tb/Yb)N and Dy/Yb suggest the precursor melts derived by low to moderate degree partial melting of a spinel peridotite mantle source. In the geochemical discrimination plots such as TiO2 vs MgO, Ba/Y vs Zr/Nb and Rb/Y vs Nb/Y and discriminant function analysis (DFA) show the MB correspond to the overlapping field between Poladpur and Ambenali Formations of Wai subgroup imply uncontaminated to significant crustal contamination (Nb/La range from 0.18–1.31; Nb/La=1 is the boundary condition) well characterized in Western Ghat sections of WDVP.

Mt. Fuji is an active basaltic volcano near the Tokyo metropolitan area; future eruptions could thus have serious nationwide impacts. To better understand recent volcanism at Fuji Volcano, we here clarify temporal variations of eruption rate and magma composition since 5.6 ka based on time-series volumetric and geochemical data of eruptive products in a new stratigraphic sequence. Volcanic activity during the studied period consisted of (i) the emission of many lava flows that formed a new volcanic edifice between 5.6 and 3.45 ka, (ii) a period dominated by explosive events both at the summit and on the flanks of the volcano between 3.45 and 2.25 ka, and (iii) a period dominated by flank fissure eruptions since 2.25 ka. The eruption rate (dense-rock equivalent, DRE) was 3.5 km3 DRE/kyr during the edifice-building period, decreased to 0.8 km3 DRE/kyr during the explosive period, and then increased to 2.0 km3 DRE/kyr since 1.5 ka. Erupted magmas were dominantly basaltic and geochemically similar through time, except for increased Sr contents and decreased Ca/Sr ratios during the explosive period. Similarly, the geochemical properties of the parental magmas did not change greatly, although the Sr contents and Ca/Sr ratios of magmas erupted during the explosive period reflect the delayed fractionation of plagioclase due to the increased water contents of the parental magmas at that time.

The Cenozoic basalts exposed in Bo Phloi Gem Field, Kanchanaburi Province, western Thailand are a host to different gem materials (e.g., sapphire, black spinel, black pyroxene and zircon) as well as other xenocrysts and xenoliths from the deep-seated formations onto the earth surface. However, only felsic xenoliths have never been investigated and reported in detail though they are in fact significant evidence of ancient tectonic processes of this area. In this study, the felsic xenoliths were sampled and classified, on the basis of petrochemistry, into granite, syenogranite, and syenite. However, they contain similar mineral assemblages including essentials of quartz, K-feldspar, and plagioclase with different proportions and accessories of biotite, zircon, and opaque minerals. Moreover, large phenocrysts of K-feldspar and plagioclase commonly present as a primary texture which are frequently corroded and replaced by ‘sieved texture’ with secondary cumulative fringe of tiny feldspar and quartz. These secondary textures clearly indicate quenching after re-heating during transportation by basaltic magma. Geochemical analyses indicate that the alkaline and peraluminous magma show enrichment of Rb and depletion of Ba, Nb, Ta, Ti with steep slope of LREE/HREE enrichment patterns. These evidences suggest low-degree partial melting of crustal materials related to the collisional S-type granite magmatism. In addition, U-Pb dating of zircon from a felsic xenolith yields 211.6±1.3 Ma comparable to the Late Triassic magmatism of the central belt granite in this region which is resulted from the collision between Sibumasu and Indochina terranes.

A área a norte de Bannach, Pará, é formada por trondhjemitos, leucogranodioritos, biotita granodioritos, tonalitos com anfibólio (± quartzo dioritos), biotita tonalitos (enclaves) e granitoides finos. O grupo de rochas com alta sílica (> 70% SiO2), representado pelos trondhjemitos, leucogranodioritos e granitoides finos, apresenta altos teores de Al2O3, CaO e Na2O em detrimento ao Fe2O3, MgO, Ni e Cr. Esse grupo exibe elevadas razões La/Y e padrão elementos terras raras (ETR) fortemente fracionado, caracterizado pela ausência de anomalias negativas de Eu. Os leucogranodioritos apresentam enriquecimentoem Na2O, Ba e Sr. Os granitoides de baixa sílica, representados pelos biotita granodiorito, tonalito com anfibólio e enclaves tonalíticos apresentam alto conteúdo de Fe2O3, MgO, Ni e Y. Os biotita granodioritos apresentam altos teores de Ba-Sr-K e moderadas a altas razões La/Yb, enquanto os demais apresentam baixas razões La/Yb. A origem dos trondhjemitos é atribuída à fusão parcial de granada anfibolitos em ambiente de subducção e os leucogranodioritos têm seu controle composicional associado a diferentes graus de fusão de basaltos enriquecidos da base da crosta. O caráter geoquímico ambíguo dos biotita granodioritos (altos conteúdos de Rb e Ba, Sr, Y e razões La/Y e Sr/Y elevadas) os aproxima dos granitos tipo Closepet. Por sua vez, o caráter menos evoluído dos tonalitos com anfibólio, bem como as baixas razões La/Yb e Sr/Y, indicam que estas possuem afinidade mantélica e que foram formadas em baixas profundidades. Admite-se que a origem dessas rochas esteja relacionada ao manto metassomatizado por fluidos da slab em ambiente de subducção.

Garnet is an important mineral phase in the upper mantle as it is both a key component in bulk mantle rocks, and a primary phase at high pressure within subducted basalt. Here, we focus on the strength of garnet and the texture that develops within garnet during accommodation of differential deformational strain. We use X-ray diffraction in a radial geometry to analyze texture development in situ in three garnet compositions under pressure at 300 K: a natural garnet (Prp60Alm37) to 30 GPa, and two synthetic majorite-bearing compositions (Prp59Maj41 and Prp42Maj58) to 44 GPa. All three garnets develop a modest (100) texture at elevated pressure under axial compression. Elasto-visco-plastic self-consistent (EVPSC) modeling suggests that two slip systems are active in the three garnet compositions at all pressures studied: {110} and {001}. We determine a flow strength of ~5 GPa at pressures between 10 to 15 GPa for all three garnets; these values are higher than previously reported yield strengths measured on natural and majoritic garnets. Strengths calculated using the experimental lattice strain differ from the strength generated from those calculated using EVPSC. Prp67Alm33, Prp59Maj41, and Prp42Maj58 are of comparable strength to each other at room temperature, which indicates that majorite substitution does not greatly affect the strength of garnets. Additionally, all three garnets are of similar strength as lower mantle phases such as bridgmanite and ferropericlase, suggesting that garnet may not be notably stronger than the surrounding lower mantle/deep upper mantle phases at the base of the upper mantle.

In this study, the petrography, mineralogy, geochemistry and petrology of Miocene aged rhyolitic, dacitic and basaltic lava flows and their pyroclastics cropping out in the Tepekent region (Konya-Central Anatolia) were investigated. The investigated rocks are basaltic trachy-andesite, andesite, dacite and rhyolite rocks with high potassium content according to the Total Alkali-Silica (TAS) diagram. However, the basaltic trachy-andesites examined are also called shoshonite according to their Na2O-K2O content. Dacitic rocks contain enclaves varying in size from mm to dm. The enclaves fall into the trachy-basalt area in the TAS diagram and exhibit a more mafic composition than the host-rocks. Basaltic trachy-andesites show holocrystalline porphyric texture, while dacites display hypocrystalline porphyric texture with varying volcanic glass contents. Basaltic trachy-andesites contain olivine, clinopyroxene, plagioclase and Fe-Ti oxide, show zeolitisation in places and iddingsitization in olivines. Dacites have a paste content consisting of volcanic glass in addition to microcrystals of the same minerals, in which amphibole, biotite, plagioclase, Fe-Ti oxide and occasionally quartz micro-phenocrysts are dispersed into it. Enclaves located in dacitic host-rocks have the fine-grained texture often found in magma mixing enclaves, however, they are composed of bladed biotite, quenched amphibole and sieve-textured plagioclase. Rhyolites contain significant amounts of sanidine and biotite as well as quartz, plagioclase and Fe-Ti oxide microphenocryst. However, they have more volcanic glass content than dacites and exhibit hypohialine porphric texture. In the Mid-Ocean Ridge Basalts (MORB) normalized trace element diagram an enrichment is observed within large ion radius lithophile elements (LILE, Sr, K, Rb, U and Th) composition, while a depletion is observed. within the high field strength elements (HFSE, Nb, Ta, Ti) contents. Rare earth element distributions normalized to chondrite, (La/Lu)N generally vary between 14-15 and present a spoon-patterned distribution describing amphibole fractionation. In the rhyolites, on the other hand, a clearly negative Eu anomaly, which expresses the plagioclase fractionation, is observed. In the light of the obtained data, it is suggested that the investigated volcanic rocks are post-collisional bimodal volcanism products bearing subduction marks and are derived from the enriched lithospheric mantle., Bu çalışmada, Tepekent yöresi (Konya-Orta Anadolu) yüzeyleyen Miyosen yaşlı riyolitik, dasitik ve bazaltik lav akıntıları ve bunların piroklastiklerinin petrografisi, mineralojisi, jeokimyası ve petrolojisi incelenmiştir. İncelenen kayalar Toplam alkali-silika (TAS) diyagramına göre yüksek potasyum içerikli bazaltik traki-andezit, dasit ve riyolit bileşiminde kayalardır. Bununla birlikte incelenen bazaltik traki-andezitler Na2O-K2O içeriklerine göre şoşonit olarak da adlandırılmaktadır. Dasitik kayalar yer yer mm’den dm’ye değişen boyutta anklav içermektedir. Anklavlar TAS diyagramında traki-bazalt alanına düşmekte olup ana kayalarından daha mafik bir bileşim sergilemektedir. Bazaltik traki-andezitler holokristalin porfirik doku gösterirken, dasitler değişen volkanik cam içerikleri ile hipokristalin porfirik doku sergilemektedir. Bazaltik traki-andezitler olivin, klinopiroksen, plajiyoklaz ve Fe-Ti oksit içermekte, nadiren zeolitleşme ve olivinlerde iddingsitleşmeler göstermektedir. Dasitler amfibol, biyotit, plajiyoklaz, Fe-Ti oksit ve nadiren de kuvars mikro fenokristallerinin içerisine dağıldığı, aynı minerallerin mikrokristallerine ilaveten volkanik camdan oluşan hamur içeriğine sahiptir. Dasitik ana kayalarda yer alan anklavlar ana mafik mineral olarak amfibol içermekte olup, magma mixing anklavlarında sık sık rastlanan ince taneli dokuya sahiptir, bununla birlikte, bıçaksı biyotit, söndürülmüş amfibol ve elek dokulu plajiyoklaz gibi dokusal özellikler sergilemektedir. Riyolitler ise kuvars, plajiyoklaz ve Fe-Ti oksit mikrofenokristalinin yanı sıra önemli derecede sanidin ve biyotit içermektedir. Bununla birlikte dasitlere göre daha fazla volkanik cam içeriğine sahip olup, hipohiyalin porfirik doku sergilemektedir. İncelenen kayaların Okyanus Ortası Sırtı Bazaltları’na (OOSB) göre normalize iz element diyagramında, büyük iyon yarıçaplı litofil element bileşiminde (BİYE, Sr, K, Rb, U ve Th) bir zenginleşme izlenirken, yüksek alan enerjili elemente (YAEE, Nb, Ta, Ti) bileşiminde ise bir fakirleşme görülmektedir. Kondrite göre normalize nadir toprak element dağılımları, (La/Lu)N genel olarak 14-15 arasında değişim göstermektedir ve amfibol fraksiyolaşmasını anlatan kaşık desenli bir dağılım sunmaktadır. Riyolitlerde ise plajiyoklaz fraksiyonlaşmasını ifade eden belirgin biçimde negatif Eu anomalisi ve sanidin fraksiyonlaşmasına işaret eden önemli derecede negatif Ba anomalisi gözlemlenmektedir. Elde edilen veriler ışığında, incelenen volkanik kayaların yitim izi taşıyan çarpışma sonrası bimodal volkanizmanın ürünleri olduğu ve zenginleşmiş litosferik mantodan türemiş oldukları önerilmektedir.

The current work deals with an experimental investigation about the influence of cut-outs on dynamic characteristics of basalt/carbon hybrid fiber reinforced composite laminates. The composite samples have been fabricated via vacuum assisted resin transfer molding technique and cut-outs in the form of triangular, square and circular shapes with equal areas have been processed on them to systematically analyze the influences of cut-outs. The dynamic characteristics of the samples have been examined by conducting free vibration-damping tests and expressed in terms of natural frequency and damping ratio using the frequency response and time-acceleration response. The results show that the damping characteristics of the composite samples can be remarkably improved with the help of cut-outs which provide improvements approximately between 2.41% and 16.65% in damping ratio values. The maximum and minimum variations in damping ratio have observed for non-hybrid carbon fiber reinforced composite samples with triangular cut-out (T-C6) and hybrid basalt/carbon fiber reinforced composite samples with circular cut-out (C-B6), respectively. On the other hand, the presence of cut-outs have led to decreases in natural frequency values as a result of reduction in stiffness caused by the cut-outs. This point out that employment of cut-outs can be a promising application to meet the natural frequency requirements of engineering systems constructed with hybrid fiber reinforced composite laminates., Mevcut çalışma, kesiklerin bazalt / karbon melez fiber takviyeli lamine kompozitlerin dinamik özellikleri üzerindeki etkisi hakkında deneysel bir araştırma ile ilgilidir. Kompozit numuneler, vakum destekli reçine transfer kalıplama tekniği ile imal edilmiş ve kesiklerin etkilerini sistematik olarak analiz etmek için üzerlerinde eşit alanlara sahip üçgen, kare ve dairesel şekiller şeklinde delikler açılmıştır. Numunelerin dinamik özellikleri, serbest titreşim sönümleme testleri yapılarak incelenmiş ve frekans tepkisi ve zaman-ivme tepkisi kullanılarak doğal frekans ve sönümleme oranı cinsinden ifade edilmiştir. Sonuçlar, kompozit numunelerin sönümleme özelliklerinin, sönümleme oranı değerlerinde yaklaşık %2,41 ile %16,65 arasında artışlar sağlayan kesikler yardımıyla önemli ölçüde iyileştirilebileceğini göstermektedir. Sönümleme oranındaki maksimum ve minimum varyasyonlar, sırasıyla üçgen kesikli hibrit olmayan karbon fiber takviyeli kompozit numuneler (T-C6) ve dairesel kesikli hibrit olmayan bazalt fiber takviyeli kompozit numuneler (C-B6) için gözlemlenmiştir. Öte yandan, kesiklerin varlığı, deliklerin neden olduğu sertlikte azalmanın bir sonucu olarak doğal frekans değerlerinde düşüşlere yol açmıştır. Bu, kesiklerin kullanılmasının, hibrit fiber takviyeli kompozit laminatlarla inşa edilen mühendislik sistemlerinin doğal frekans gereksinimlerini karşılamak için umut verici bir uygulama olabileceğini göstermektedir.

Application of microwave heating technique is highly promising in assisting rocks breakage and recycling coarse aggregate in waste concrete. This work focus on crack propagation behavior and hence damage of hard rocks subjected to microwave irradiation. Heating effects of basalt and its main mineral components are investigated experimentally using a multimode industrial microwave system. Crack characterization of basalt after irradiating are observed using scanning electron micrograph (SEM). A theoretical model based on heating effects of mineral components is established to deduce crack propagation within basalt under microwave irradiation. Temperature rise of magnetite is drastic while that of other mineral components are tardy. Fracture of basalt is induced by predominant radial crack propagation around the rapidly heated mineral particle. Cracks can be divided into short cracks and long cracks by a characteristic length during extending. Microwave energy required for extension of cracks with characteristic length is minimum. Propagation of initial short cracks results in greater extent of damage evolution instantaneously. Moreover, damage increases with the mineral content of magnetite and decreases with crack density.

The Galapagos Archipelago is the surface expression of an active hotspot or long-lived mantle plume. The Archipelago consists of a group of 13 main islands which are located in the eastern central Pacific Ocean about 1,000 km west of the northern edge of the South American continent, east of the East Pacific Rise and south of the Galapagos spreading center. Because of the large distance to the nearest continental land mass, Galapagos can be seen as an almost isolated sedimentary system. A provenance study conducted on samples collected from seventeen beaches on eleven islands, demonstrates that mineral grains and particles were derived from weathering of predominantly basaltic rocks and were transported within the islands, between the islands or inside the coastal area around the Archipelago. The exclusion of external sources allows advanced studies about erosion processes, transport pathways of particles and the accumulation of autochthonous sediments. The combined usage of optical particle size and shape analysis with RAMAN spectroscopy allows a successful spatial delimitation of host rocks and a reconstruction of transport pathways. The analyzed samples can be subdivided into three groups: 1) Type-A sediments: fine-grained and sampled on beaches of the oldest islands in the eastern part of Galapagos. The composition of volcanic minerals corresponds to the alkaline character of the basaltic source rocks. 2) Type-B: well sorted sediments characterized by medium-grained olivine, pyroxene, plagioclase and even a small amount of quartz grains. The islands of this group are located in the central region of the Archipelago. 3) Type-C samples: olivine and pyroxene are the predominant volcanic minerals. These samples indicate bimodal, coarse-grained size distributions and large proportions of pumice and are found in Floreana in the south and the youngest islands Isabela and Fernandina in the west of Galapagos.

Early Paleozoic ophiolitic melanges in the Altyn Tagh Orogen, southeastern Tarim, yield a large range of formation ages and geochemical affinities. This study focused on the Hongliugou ophiolitic melange in the North Altyn Tagh subduction-accretion belt and involved mineral chemical, zircon geochronological, and whole-rock elemental and isotopic investigations of the ultramafic and mafic rocks. In the studied lherzolite samples, Cr-spinel, olivine, and pyroxene show mineral chemistry akin to that of abyssal peridotite. Subhedral-anhedral Cr-spinel grains with high Cr# values (100*Cr/[Cr+Al] of 30–40) and negative oxygen fugacity (fO2) values represent original spinel formed during mid-ocean ridge basalt (MORB) melt extraction. Other subhedral-anhedral and euhedral Cr-spinel with low Cr# values of

Inclusions of basaltic melt trapped inside of olivine phenocrysts during igneous crystallization provide a rich, crystal-scale record of magmatic processes ranging from mantle melting to ascent, eruption, and quenching of magma during volcanic eruptions. Melt inclusions are particularly valuable for retaining information on volatiles such as H2O and CO2 that are normally lost by vesiculation and degassing as magma ascends and erupts. However, the record preserved in melt inclusions can be variably obscured by postentrapment processes, and thus melt inclusion research requires careful evaluation of the effects of such processes. Here we review processes by which melt inclusions are trapped and modified after trapping, describe new opportunities for studying the rates of magmatic and volcanic processes over a range of timescales using the kinetics of post-trapping processes, and describe recent developments in the use of volatile contents of melt inclusions to improve our understanding of how volcanoes work. ▪ Inclusions of silicate melt (magma) trapped inside of crystals formed by magma crystallization provide a rich, detailed record of what happens beneath volcanoes. ▪ These inclusions record information ranging from how magma forms deep inside Earth to its final hours as it ascends to the surface and erupts. ▪ The melt inclusion record, however, is complex and hazy because of many processes that modify the inclusions after they become trapped in crystals. ▪ Melt inclusions provide a primary archive of dissolved gases in magma, which are the key ingredients that make volcanoes erupt explosively.

Recycling of asphalt mixes can be defined as the restoration of aged mixes. The purpose of this research is to evaluate some old asphaltic surface courses in Damietta governerate for their potential of being recycled. Two types of old asphalt surface in Damietta were sampled and transported to the highway laboratory at Mansoura University. One of the two mixes was a dolomite crushed stone mixed at 6.64 asphalt content and the other was a basalt aggregate mixed at 5.2% asphalt content. Control mixes were also prepared using two virgin aggregates similar to those aggregates under study and designed according to Marshall method. It was found that the two Damietta asphalt mixes had high potential to be hot recycled after the addition of a 12% softener and 30% virgin aggregate. No extra addition of asphalt cement was needed in most cases.

Mid-Tertiary volcanism in the Western Desert Egypt was associated with the opening of the Red Sea, a period of 30 Ma. Basalts are composed of plagioclase, pyroxene, and olivine minerals. Basalt used as natural volcanic pozzolans materials; represent large interest of researches as a real alternative to replace ordinary Portland cement (OPC). The present work was performed on six samples of experimental cement clinker, one with ordinary raw materials (limestone & shale) as a reference sample, and five others with various substance (limestone & basalts), which show the possibility of the utilization of natural pozzolan for maintainable construction material. The chemical, mineralogical composition and texture produced clinkers were determined by scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD) and differential thermal analysis (DTA). It is concluded that the produced clinkers which made from basalt are coincidence ordinary Portland cement clinker. They are characterized by increasing in setting time, compressive strength and resistance to sulfate attack.

This article provides data on cristobalite and tridymite from the Arsenatnaya active fumarole of the Tolbachik volcano, Kamchatka, Russia. The minerals occur in associations with fumarolic sylvite, sanidine, cassiterite, hematite, pseudobrookite, johillerite, tilasite, and badalovite. Fumarolic cristobalite is tetragonal (α-modification); the unit-cell parameters for one sample are: а = 4.975 (7) A, с = 6.944 (13) A, and V = 171.89 A3. There are two types of tridymite, that is, monoclinic (MC) and orthoorthorhombic (PO-10), in the Arsenatnaya fumarole. The unit-cell parameters of these tridymite modifications are: a = 18.553 (5) A, b = 5.006 (1) A, с = 25.952 (10) A, β = 117.68 (2)°, V = 2134.3 (11) A3 (MC); a = 9.941 (2) A, b = 17.165 (4) A, с = 82.362 (18) A, and V = 14053.4 (29) A3 (PO-10). Mineral assemblages of cristobalite and tridymite indicate high-temperature formation conditions of these minerals not lower 450–500°С with considerable participation of HCl and HF in process of basalt alteration by fumarolic gas. The surrounding basalt was a source of silicon. This element was probably transported in the form of SiX4, where X = F, Cl.

Peridotites of an unusual orbicular structure, attributed to the impregnated type of rocks, were found in ophiolites of the Voikar massif (Polar Urals). Orbicules in these rocks are composed of a secondary clinochlore–diopside aggregate containing grains of primary clinopyroxene and pargasite. The morphology and composition of orbicules make it possible to attribute them to segregations (globules) of the melt in the olivine matrix of peridotites that have experienced partial crystallization in situ. According to geochemical modeling results, these melts had characteristics transitional to boninites, corresponding to the suprasubduction conditions. The formation of orbicular peridotites was associated with blocking intergranular channels of the percolating basaltic melts.

The newly discovered East Longjing-2 hydrothermal field (ELHF-2) is located on the Dragon Horn oceanic core complex of the ultraslow-spreading Southwest Indian Ridge, approximately 12 km from the ridge axis. This study measured the chemical compositions of pyrite from ELHF-2 using a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate the genesis of the field. Three generations of pyrite were classified, and found that: Py1 and Py2, rich in V, Mn, U, and Se, occur in altered basalt debris and the silica alteration matrix, respectively. Py3 was mainly intergrown with chalcopyrite in quartz veins and had higher Cu, In, Ag, Sb, and Au contents than Py1 and Py2. Some elements, such as Au, Se, and Pb, are likely presented as direct substitution with Fe2+ in pyrite, while Cu, Zn, Co, Ni, and Ag probably occur both as direct substitution with Fe and as distributed micro- to nanoparticle-sized sulfides. Meanwhile, the occurrence of V, Mn, and U is likely presented as oxide inclusions. Trace element geochemistry suggested that the pyrite was formed under high-temperature conditions, and the ore forming elements were likely derived from ultramafic rocks. In addition, Py1 and Py2 were formed under higher water/rock ratio and higher temperature conditions, with more seawater involvement compared with Py3. The formation of ELHF-2 was probably driven by exothermic serpentinization reactions with an additional magmatic heat. This study shows that high-temperature hydrothermal circulation driven by magmatic activity can be developed on distal rift flank areas of magma-starved ultraslow-spreading ridges.

Fluid-inclusion studies were conducted on amethyst quartz from three different geological environments: basalt cavities; hydrothermal veins; and granitic pegmatites of Eastern Brazil, to understand the conditions of amethyst crystallisation in each of these environments. In samples from basalt cavities, fluid inclusions are exclusively one-phase aqueous types suggesting a low-temperature formation environment. Crystals from the two other environments show that fluid inclusions can be either one-phase aqueous, two-phase aqueous, three-phase aqueous carbonic, or three-phase aqueous with the presence of precipitated solid halite. The carbonic composition of the system H2O–CO2–NaCl was confirmed by Raman spectroscopic analysis and suggests a metamorphic or magmatic fluid source. Fluid inclusions trapped in samples from hydrothermal veins reveal at least two different fluid generations based on homogenisation temperatures. The first generation has minimum trapping temperatures between 249°C and 391°C. The second generation of lower temperature fluids has minimum trapping temperatures varying from 82°C to 203°C. Fluid inclusions of this group record eutectic temperatures that indicate the presence of Ca and Fe cations in addition to Na. Fluid inclusions trapped in amethyst from a pegmatite body have moderate salinity values between 15 and 25 eq. wt.% NaCl, thus reflecting the elevated salt content in pegmatite-forming fluids. In this sample, the first fluid generation is represented by aqueous fluid inclusions with minimum trapping temperatures ranging from 268°C to 375°C. The estimated eutectic temperatures, generally below –50°C, indicate the presence of Ca cations in addition to Na. Minimum trapping temperatures correspond to temperatures of late-to-post-pegmatitic hydrothermal stages. The second generation records minimum trapping temperatures between 125°C and 247°C. Amethyst from both hydrothermal veins and pegmatite environments contain solid inclusions of hematite, an indication that the mineralising fluid was Fe rich and thus, possibly magmatic in origin.

The highly siderophile element (HSE) or platinum group element (PGE) and Os isotope systematics of basaltic volcanics have recently received a significant attention because of their potential to constrain the petrological processes on magma generation and evolution. The HSE and Os isotope data, which are generally observed at very low concentrations in basalts and obtained by modern enrichment and analytical techniques, are frequently used in petrological studies. The HSE contents and ratios from whole-rock analysis of basalts, and combined evaluation with the theoretical knowledge and modelling of HSE behaviour during the partial melting of mantle and the differentiation of basaltic magma would provide opportunity for geochemical modelling on mantle melting. Besides, HSE contents and Pd-PGE/Ir-PGE ratios are important indicators for the nature of mantle sulfides, the sulfur saturation conditions of the mantle source, sulfide segregation, fractional crystallization, crustal assimilation and partial melting degrees in the origin and evolution of mantle-derived magmas. Therefore, in addition to the traditional whole-rock geochemical data obtained from Cenozoic aged basalts observed widely in Turkey, HSE and Os isotope systematics of these basalts can contribute to define the geochemical features of the mantle source, and to model petrological processes which are effective in the magma evolution. © 2022 General Directorate of Mineral Research and Exploration (MTA). All rights reserved.

The volcanic region of Campo de Calatrava, which is located in the centre of the Iberian Peninsula, is characterized by monogenetic, strombolian and hydromagmatic volcanic activity. It is made up of more than two hundred volcanoes distributed over an area of about 4000 km2. They are mainly comprised of sodic alkaline and ultra-alkaline rocks, few evolved rocks (basalts, basanites, olivine nephelinites and olivine melilitites) and occasionally ultrapotassic rocks (olivine leucitites) and carbonatites. New radiometric ages (K/Ar and 40Ar/39Ar) allow a better understanding of the distribution and temporal evolution of volcanic activity in this region. The oldest volcanism is ultrapotassic and restricted to a single vent. The new 40Ar/39Ar ages date this centre between 7.4 Ma and 7.1 Ma, so it was contemporary with other ultrapotassic activity in the Iberian Peninsula (the lamproites of the SE of Spain). After a break of about 3 million years, the main volcanic activity in the region took place, without apparent major pauses, from about 4 Ma to less than 0.7 Ma, with most radiometric ages concentrated between 3.5 and 1.5 Ma. Except in the case of olivine leucitites, there are no significant compositional differences related to the ages of the volcanoes, although there may be minor variations. The mildly alkaline volcanoes (basalts and basanites) tend to be concentrated in the central areas of the region, while on the peripheral areas, the volcanoes are essentially ultra-alkaline. The spatial age distribution of the volcanoes seems to show a shift of the volcanic activity over time towards the northeast. The spatial age distribution of the volcanoes seems to show a displacement of volcanic activity over time towards the northeast, accompanied by an increase in its intensity.

Basalt stone tools were collected from some Iraqi Archaeological Sites. Twenty-one samples were studied petrographically, mineralogically, and chemical composition. Five samples were from the Gaara Depression north of Rutba town, seven samples from Tarmiya, north Baghdad, seven samples from Dalmij site, east of Diwaniya city, and two samples from Jordan, which were used for comparison. The studied samples were classified into three groups, according to their mineralogy and texture: Group A: Vesicular Basalt, Group B: Dolerite, and Group C: Olivine Basalt. These stones most probably were used as a hand axe, grinder, hammer, and other uses, as well as for buildings, like those used in Qasar Al- Azraq and Umm Al- Jamal archaeological sites in Jordan. These basalt rocks most probably were transported by an ancient man from Harrat Al-Sham, which extends through Syria-Jordan-Saudi Arabia, or from NE Syria through a trade route that connected between source areas and the studied archaeological sites in Iraq.

Weathered basalt (WB) is a useless and costless material with a negative environmental impact. The use of WB to replace clay in Portland clinker manufacturing is a successful strategy to enhance clinker quality, cost and reduce environmental impact. In this study, four mixes were prepared by replacing clay with 25, 50, 75 and 100 wt% of WB (M1-M4, respectively) keeping the ratio of the other mix constituents (limestone, sand and iron ore) constants. Another mix (M5) was prepared using 100% WB, with increasing sand percent and deduction iron ore content. The major innovation presented in M5 is the possibility to make a substitution of clay and iron ore with WB. This allows for much higher levels of mixture cost reduction. WB allows higher levels of substitution down of the number of raw mix components and improvement in burnability. Also promotes the formation of main clinker phases, especially alite phase.

The earth crust is made up of variety of minerals. These minerals are having very significant applications in our day today life. The various studies, characterizing physical, chemical, electrical, structural properties, have been carried out on the Lonar crater for studying mineralogy, surface morphology and geology but has not been done by remote sensing technology. So, the proposed work focused on exploring the mineralogy at the Lonar crater by using high resolution hyperspectral imageries. The spectral reflectance of minerals was characterized by using FieldSpec4 spectroradiometer. The minerals at Lonar crater were explored by performing preprocessing and spectral analysis. The techniques used in the work are Spectral Angle Mapper and Spectral Feature Fitting. The results of the work marked the presence of pigeonite and augite at Lonar crater which indicates that this crater is the result of extrusive volcanic activity. Also, the presence of augite underneath basaltic igneous rocks as the rock type of Lonar crater. The salinity of the Lonar lake is proved by the presence of mirabilite and salt. Thus, the important results of this work are presence of minerals quartz, actinol, jarosite, pigeonite, augite, albite, mirabilite and scolecite. The significance of these minerals related to the crater is discussed here. It also validated the existence of these minerals which were identified through the previous geological, chemical, physical, electrical and magnetic studies and the minerals pyrite, chlorite, richter, illite, limonite, allanite, amphibolite and margarite were also identified.

The thermoelastic properties of minerals in mantle xenoliths combined with the thermal states can provide an integrated understanding of the petrophysics of the lithospheric mantle. Here, we conducted high-pressure and high-temperature experiments on the main minerals (e.g. olivine, orthopyroxene, clinopyroxene, spinel, and garnet) in peridotite xenoliths from basalt of the eastern North China Craton (NCC) using in situ synchrotron single-crystal X-ray diffraction combined with diamond anvil cells. The pressure-temperature-volume data were fitted to the third-order Birch-Murnaghan equations of state and yielded the thermoelastic parameters that included bulk modulus, pressure and temperature derivatives, and thermal expansion coefficients. The density profiles of the eastern NCC during the destruction process since the Mesozoic are presented from the temporal and spatial aspects. The lithospheric density dramatically decreased during destruction, and high heat flow may have been a trigger. The spatially distributed density profile also provides firm evidence for lateral heterogeneities in the eastern NCC. This may suggest that the present mantle is characterized by heterogeneous destruction of the NCC.

The present study is a multi-analytical approach to the characterization of several basalt stone samples, from Umm el-Jimāl Cultural Heritage site, northern Jordan, which represents ancient trade routes between Arabian Peninsula and Syria. In particular, Micro-X-ray Fluorescence Mapping as new in the mineralogy, X-ray Diffraction Energy Dispersive X-ray spectroscopy are used for the determination of the petrological, geochemical, and mineralogical characteristics of the basalt used in this archeological site for conservation purposes. The results reveal that it belongs to the alkaline trachy-basalt to basanite-tephrite type. With predominant quartz, olivine, pyroxene, and plagioclase (albite) as major elements, the vesicular texture is occupied with secondary minerals such as biotite, gypsum, and calcite.

The Maguan (MG) region in the southwestern part of the South China Block contains many Neogene potassic basaltic volcanic rocks along the Ailao Shan–Red River (ASRR) shear zone. These alkaline volcanic rocks contain abundant peridotite xenoliths which are mostly spinel (Spl)-facies lherzolite. We examined xenoliths in young, ~12 Ma, alkaline basalts. Most contain clinopyroxene (Cpx), >15 vol%, and minor xenoliths contain low Cpx, ~10 vol%. Olivine (Ol) shows forsterite components ranging from 88.6 to 90.1 in most lherzolite and from 90.4 to 90.8 in depleted lherzolite, Spl Cr# (=Cr/(Cr + Al)) between 0.08–0.11 for lherzolite and 0.17–0.22 for depleted lherzolite. Platinum group elements (PGE) show a near flat primitive mantle-normalized pattern; the ratios of IPGE/PPGE are 1.3–1.8 for lherzolite and 2.1 for depleted lherzolite. The xenoliths do not contain metasomatic minerals, but Cpx in depleted lherzolite samples is enriched in light rare earth elements (LREE; (La/Sm)N = 0.97–1.74). Two pyroxene geothermometry gives the temperatures ranging from 1029 °C to 1148 °C (average 1087 °C, n = 13). Spl–Ol geothermobarometry yields the oxidation state ranging from FMQ −1.5 to −0.25 with an average value of FMQ −0.59 (n = 13), which is comparable to those of abyssal peridotite and the asthenospheric mantle. The calculated temperatures and oxidation state are similar among samples independent of mineralogy and mineral chemistry, suggesting that partial melting and the cryptic metasomatism did not change the oxidation conditions. The data suggest that the subcontinental lithospheric mantle (SCLM) beneath the region formed from the asthenosphere mantle. Since the South China Block is generally underlain by Proterozoic SCLM, the data obtained this study suggest that the ancient lithosphere was replaced by the asthenospheric mantle in the local extension along the ASRR shear zone.

The present study deals with the use of locally prepared rice husk ash (RHA)-based sodium silicate for alkaline activation of laterites (uncalcined (LNW) and calcined (LCA)). RHA-based activator (SSR) was prepared by adding as-collected RHA to 6 M NaOH at a solid/liquid mass ratio of 0.56. The various proportions of metakaolin (MK) and basalt powder (BA) influenced the final properties of the geopolymer products. After 28 days of curing at room temperature, XRD, SEM and FT-IR analyses were used to study the evolution phases. Uncalcined laterite-based formulations showed their highest compressive strength at 29.86 MPa with 20 wt.% of MK, whereas calcined ones showed the most elevated strength at 47.02 MPa, with the addition of 25 wt.% MK. Further additions above these thresholds tend to reduce strength and increase setting time. Substitution of calcined laterite with basalt powder permitted to control the porosity of samples at low values with the consequent reduction of strength. In general, the water absorption and apparent porosity decrease with addition of metakaolin in raw laterite-based formulations and relatively decrease with addition of basalt powder in calcined laterite-based formulations, while bulk density remains relatively constant. The locally produced RHA-based alkaline activator is efficient for laterite geopolymerization, resulting in products with robust mechanical and physical properties capable of fostering application in quality housing.

The Proterozoic rock record displays secular change from ferruginous to an oxic hydrosphere over the course of 2 billion years; however, debate continues on the periodicity, rate of change and steps in following atmospheric oxygenation that ultimately led to an oxygenated ocean. This is partly due to poor preservation of the Paleoproterozoic marine sedimentary record in the few hundred million years after the Great Oxidation Event. Whereas the 2.0 Ga rock record preserves only rare chemical sediments, it contains significant mafic igneous provinces, which are known to locally host volcanogenic massive sulfide (VMS) deposits. These hydrothermal environments fossilize the ancient interaction at the seafloor interface between volcanic rocks and seawater. In this context, the 2.01 Ga Degrussa VMS deposit of the Paleoproterozoic Capricorn Orogen, Western Australia offers an opportunity to probe the ancient ocean composition. The Degrussa VMS deposit preserves massive sulfide mineralisation (pyrite – chalcopyrite – pyrrhotite ± sphalerite ± galena) hosted in turbiditic sedimentary rocks interlayered with basaltic flows and cut by numerous gabbroic sills. Exhalite layers are composed of hematite and jasper associated with magnetite. This study documents the multiple sulfur isotope composition of the Degrussa VMS deposit through an integrated analytical approach, which comprises bulk fluorination gas chromatography isotope ratio mass spectrometry and in situ secondary ion mass spectrometry. By comparing the ultra-high precision bulk measurements (n = 21) with in situ measurements of variably-textured grains of pyrite, chalcopyrite and pyrrhotite (n = 252), we determine that VMS mineralisation yields δ34S between +2‰ and +5‰ with a peak at ∼+2.9‰, and negative Δ33S signal ranging from −0.08 to 0.00‰. A two component δ34S-Δ33S mixing model indicates 11% of H2S derived from thermochemically reduced seawater sulfate mixed with magmatic H2S. The most negative Δ33S values must be explained by interaction with sulfate in the near-surface, undergoing complex dissolution-reprecipitation reactions, necessitating a minimum seawater sulfate reservoir of ∼2 mmol/L, or 7% modern seawater at 2.01 Ga.

The southwest Sabzevar basin situated in the Sabzevar zone is considered to be an attractive metallogenic province in Iran that hosts both volcanogenic massive sulfide (VMS) and stratiform manganese deposits. The Nudeh Besshi-type VMS deposit is located in the Lower Late Cretaceous volcano-sedimentary sequence. The ore mineralization in this deposit is hosted in the alkali olivine basalt flow and tuffaceous silty sandstone rocks. The Nudeh VMS deposit consists of 2 million metric tons of Cu-Zn massive sulfide overlying a Cu-Fe-rich stringer. The massive sulfide orebody consists dominantly of pyrite, chalcopyrite, friedrichite, magnetite, and sphalerite, together with minor quartz, chlorite, and sericite. Chloritization, silicification, and sericitization are the main wall-rock alteration types; alteration intensity increases towards the stringer zone. Chloritized footwall rocks extend up to 20 m below the stringer zone. The quartz-bearing stringer veins also contain pyrite, chalcopyrite, magnetite, and bornite. Magnetite crystals from the stringer ores show variable contents of many elements, such as MgO (0.05 wt%), Al2O3 (0.63 wt%), TiO2 (0.07 wt%), V2O3 (0.045 wt%), SiO2 (0.65 wt%), CoO (0.10 wt%), NiO (0.009 wt%), ZnO (0.023 wt%), and CaO (0.03 wt%). The moderate to high V contents are interpreted to result from relatively reduced, seafloor hydrothermal activiy. Compositional variations of magnetite are possibly related to variations in oxygen fugacity, temperature, and water/rock interaction. Within the stringer zone, chlorite 2 (Chl-2) in the vein-veinlets and chlorite 1 (Chl-1) in the chloritized alkali olivine basalt rock are chemically indistinguishable, with 26.92–34.67 wt% FeO and 5.99–14.01 wt% MgO. Chlorite geothermometer studies indicate crystallization formation temperatures of 414 °C (Chl-1) and 303 °C (Chl-2), respectively.

Background Three stages of basalt weathering are known: early or incipient weathering, intermediate weathering and advanced weathering. The Late Oligocene basalt of Gebel Qatrani in Fayum Depression, Egypt, shows signs of early weathering, particularly exhibited in basalt spheroids found at the top of the basalt flow. The present paper gives the results of detailed petrographical, mineralogical and geochemical study of the weathering of these basalt spheroids. Results The core-stones of the basalt spheroids are composed of phenocrystals of plagioclase feldspars and clinopyroxenes set in a groundmass of tiny feldspars and pyroxenes, relatively altered olivine and opaque minerals. The basalt is subalkali (tholeiitic). The outer weathered shells surrounding the core-stones are composed of partly altered feldspars and pyroxenes. The calculated weathering indices show that there is marked weathering trend from the core-stones of the spheroids to the outer shells. The chemical mobility of the elements shows marked depletion of Mg, Ca, Na and K from the core-stones to the outer shells due to the weathering of olivine, pyroxene and feldspars. The trace elements Rb, Sr, Ni, V, Cr and Zn are also depleted. Conclusions The weathering of basalt spheroids from Gebel Qatrani, Fayum Depression, Egypt, is of the incipient type. The degree of weathering from the core-stones of the basalt spheroids to the corresponding weathered shells indicates that the weathering occurred under predominantly semiarid to arid conditions.

Harvesting quantitative fO2 information from synchrotron μ-XANES measurements of Cr2+/ΣCr in olivine phenocrysts requires robust thermodynamic or empirical models that can accurately predict Cr2+/ΣCr in basaltic liquids as a function of fO2, temperature, and liquid chemistry. We present the results from a combined experimental-XANES study designed to illuminate how evolving liquid chemistry and decreasing temperature influence the equilibrium Cr2+/ΣCr ratios in crystallizing basaltic liquids. The Cr valence dataset produced from these experiments was fit with a symmetric regular solution model; this fitting generated a model equation that predicts the Cr2+/ΣCr in basaltic magmas. Using MELTS in conjunction with the newly calibrated Cr valence model, we calculated the Cr2+/ΣCr of a tholeiitic liquid undergoing isobaric equilibrium crystallization at 2.5 °C intervals. The modeling results indicate that Cr2+/ΣCr evolves dynamically in crystallizing liquids composition and may be partially decoupled from bona fide changes in magmatic fO2. These calculations suggest that the increasing iron content of the residual liquid is the most influential factor influencing the Cr2+/ΣCr of the residual liquid. Olivine normative tholeiitic liquids following a liquid line of descent parallel to an oxygen fugacity buffer curve experience significant decreases in the equilibrium Cr2+/ΣCr of their residual liquids. Our modeling also demonstrates that Cr2+/ΣCr values preserved in early olivine phenocrysts indeed reflect the magmatic fO2 conditions under which they grew; however, the effects of magmatic fO2 are also superimposed on the underlying influences of temperature and melt chemistry.

Basaltic rocks and their content of ultramafic xenoliths are common in the Ghab Pliocene Volcanic Field in northwestern Syria in the form of lava flows, cinder cones and pyroclastic deposits. The rocks occur within the Ghab pull- apart graben that formed by sinister strike slip faults within the zone that defines the boundary between the African and the Arabian plates. Three petrographic types occur: basanite, olivine basalt and more commonly alkali olivine basalt. The peridotite xenoliths are spinel lherzolite and harzburgite. Geochemical analysis indicates that the basalts are mostly alkaline to subalkaline. A distinctive feature of these rocks is the narrow compositional variations in the content of most major oxides and minor elements, SiO2 (44.33 - 46.43 wt%) and MgO (4.01 - 8.28 wt%). Some of the refractory and high field strength elements and incompatible minor elements in the basalts are relatively high (Cr average = 303 ppm and Ni average = 185 ppm) compared with their content in average basalts. These geochemical characteristics reflect crystallization of the Ghab basalts from pristine and primary magmas that have experienced minimal fractional crystallization and crustal contamination. Similarly, chemical compositions of the ultramafic xenoliths vary within a restricted geochemical range. They are compatible with the generation of these rocks from partial melting of a primitive mantle pyrolite to yield the xenoliths. These magmatic processes operated during the Pliocene in a regional transtensional stress environment attending the development of the Dead Sea Rift.

Most heritage monuments in India are made of stones, representing the rich cultural traditions of the region. Due to human interventions and natural causes these monuments are undergoing deterioration and need effective intervention. The weathering of stone monuments can be attributed to stone characteristics and also to the environment. This study attempts to investigate and assess extent of deterioration in two monuments, Khidrapur temple and Panhala Fort. Engineering properties and chemical composition of stones were determined. XRD analysis revealed the presence of minerals, pyroxene and olivine. SEM images show the formation of detritus minerals indicating the intrinsic weathering of rock. These studies reveal that agents of weathering have deteriorated the building stones from outside and inside also. Micro structural analysis also helped to identify the intrinsic characteristics of stone, which will aid in formulating preservative treatments and procedures. This study forms a base for sustainable conservation of these heritage monuments. The outcome of the study will be applicable for determining conservation strategies for the monuments built in basalt and laterite.

Abstract We conducted the geochemical modeling of trace element contents for primary melts of olivine-phyric rocks from Kamchatsky Mys. This modeling reveals substantial chemical heterogeneity of their source while the average source composition is close to the enriched DMM (E-DMM). The average estimation of the melting degree is in the range from 9.1 ± 3.8% for the model of modal batch melting to 15.4 ± 5.2% for the model of accumulated fractional melting, which is slightly higher than the estimation for primitive mid-ocean ridge basalt (MORB) glasses (7.4 ± 2.2% and 12.5 ± 3.8% respectively). It is in a good agreement with high melting degrees estimated earlier for other rocks of the Kamchatsky Mys ophiolites. Low pressure of mantle melting caused by the elevated speed of decompression relative to the average MORB could explain elevated melting degrees estimated for Kamhcatsky Mys ophiolites as well as their characteristic Sr-anomalies and sulfide saturation on the earliest stages of magmatic evolution.

Alkaline basalts of Bafang and its environs are consisted of feldspars, olivines, pyroxenes and oxides which appear as phenocrysts, microphenocrysts and microcrysts. Feldspars are plagioclases (An67.97-15.84Ab69.19-30.43Or20.59-1.51) and anorthoclases (Ab68.11-61.20Or33.87-20.91An10.98-4.93). Plagioclases are the most abundant amount these feldspars. Anorthoclases appear only in mugearite (BAF 3 and BAF 37) the most differentiated of the studied alkaline-basalts. In High Magnesian basalt, (HMg-B) plagioclases are labradorites (An67.97-59.30Ab38.74-30.43Or2.75-1.60) and sanidine (An45.44-31.82Ab62.66-51.79Or5.52-2.77), whereas in Low Magnesian basalt (LMg-B) there are labrador (An67.4.75-51.96Ab44.98-33.72Or3.06-1.51), andesine (An45.44-31.82Ab62.66-51.79Or5.52-2.77), oligoclase (An26.65-15.84Ab69.19-63.57Or20.59-8.55) and anarthoclase (Ab68.11-61.20Or33.87-20.91An10.98-4.93). Olivines are magnesian (Fo86.7-50.1) and ferriferous (Fo48.8-37.8). In HMg-B, olivine are only magnesian. These olivines are chrysolites and hyalositerite. In LMg-B, olivines are magnesian and ferriferous with the predominance of ferriferous. They are chrysolites, hyalositerite and hortonolite. Pyroxenes are Ca, Mg and Fe clinopyroxenes. There are diopsides (Wo51.94-45.02En44.41-33.16Fs16.42-10.70) and augites (Wo44.88-43.64En41.03-37.04Fs18.25-14.43). Oxides are magnetites represented by ulvospinel (Usp90-75Sp2-7Mt5-23). Fractionation of ferromagnesian minerals (opaque oxide, olivine and pyroxene) is the main differentiation process. Two stages of fractional crystallization can be distinguished: the first stage comes with basanites and the second with hawaiites to mugearites. Chemical compositions of phenocrystals in studied basaltics lavas record signatures of magma recharge by pulsatory intrusions of new magma into the existing magma reservoir before the eruptions.

Intracrystalline distortions (like undulose extinction, dislocations, and subgrain boundaries) in olivine from naturally-deformed peridotites are generally taken as signs of dislocation creep. However, similar features in olivine phenocrysts that have been found in basaltic magmas are still not well understood. In particular, whether subgrain boundaries in olivine phenocrysts arise from plastic deformation or grain growth is still debated (in the latter case, they are essentially grain boundaries but not subgrain boundaries. Therefore, we used hereinafter subgrain-boundary-like structures instead of subgrain boundaries to name this kind of intracrystalline distortion). Here we carried out a detailed study on dislocations and subgrain-boundary-like (SG-like) structures in olivine phenocrysts from two Hawaiian basaltic lavas by means of petrographic microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). Abundant and complex dislocation substructures (free dislocations, dislocation walls, and dislocation tangles) were observed in the decorated olivine grains, similar to those in olivine from peridotite xenoliths entrained by the Hawaiian basalts. The measured average dislocation density is (2.9±1.3)×1011 m−2, and is three to five orders of magnitude higher than that in laboratory-synthesized, undeformed olivine. TEM observations on samples cut across the SG-like structures by FIB (focused ion beam) demonstrated that this kind of structures is made of an array of dislocations. These observations clearly indicate that these structures are real subgrain boundaries rather than grain boundaries. These facts suggest that the observed high dislocation densities and subgrain boundaries cannot result from crystal crystallization/growth, but can be formed by plastic deformation. These deformation features do not prove that the olivine phenocrysts (and implicitly mantle xenoliths) were deformed after their capture by the basaltic magmas, but can be ascribed to a former deformation event in a dunitic cumulate, which was formed by magmatic fractionation, then plastically deformed, and finally disaggregated and captured by the basaltic magma that brought them to the surface.