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Shao Yong Jiang - One of the best experts on this subject based on the ideXlab platform.
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in situ elemental and boron isotopic variations of Tourmaline from the maogongdong deposit in the dahutang w cu ore field of northern jiangxi province south china insights into magmatic hydrothermal evolution
Ore Geology Reviews, 2020Co-Authors: Shao Yong JiangAbstract:Abstract In this paper, we present a systematic investigation of in-situ major, trace elements and boron isotopic variations of Tourmaline from the Maogongdong deposit in the Dahutang W-Cu ore field of northern Jiangxi Province, South China, which demonstrates both the magmatic and hydrothermal origin for the formation of the Tourmalines. The Tourmaline occurs mainly in granites, pegmatites and quartz veins. Five types of Tourmaline are identified: (1) disseminated Tourmaline in the pegmatites (Tur-P type); (2) isolated and disseminated Tourmaline clots in the granites (Tur-R1 type); (3) typical anhedral quartz-Tourmaline nodulars in the granites (Tur-R2 type); (4) Tourmaline clots in quartz-tungsten-sulfide veins (Tur-Q1 type); (5) euhedral needle-columnar Tourmaline crystals in quartz or quartz-sulfide veins (Tur-Q2 type). These Tourmalines mostly fall into the alkali group representing schorl-dravite solid solution series. Petrography and chemical discrimination diagrams suggest that the Tur-P, Tur-R1 and Tur-R2 are of magmatic origin and the Tur-Q1 and Tur-Q2 are of hydrothermal origin. Hydrothermal Tourmalines have higher Mg/(Mg + Fe) ratios, higher Li, Be, Sn, Rb, Co, Sr, V, Pb, Zn, Ni contents and lower Na/(Na + Ca) ratios, lower Nb, Ta contents than the magmatic Tourmalines. The Tur-P show negative Eu anomalies and their REE patterns are equivalent to the muscovite granite. The Eu anomalies in Tur-R1 and Tur-R2 change from negative to positive. Compared with magmatic Tourmalines, Tur-Q1 and Tur-Q2 exhibit more pronounced positive Eu anomalies, and a majority of the Tur-Q1 and Tur-Q2 have higher ∑REE contents. Tourmalines from the Maogongdong deposit have a B isotopic composition range from −17.9‰ to −12.3‰. The average δ11B values of the Tur-P, Tur-R1 and Tur-R2 are −13.8‰, −14.8‰ and −14.5‰, respectively. Tourmalines in early hydrothermal veins have similar δ11B values (average −14.6‰), while the Tourmalines in later hydrothermal veins have slightly lower δ11B values (average −16.5‰). Boron isotopic variations of Tourmaline are controlled by temperature, Rayleigh fractionation and external fluid.
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in situ elemental and boron isotopic variations of Tourmaline from the sanfang granite south china insights into magmatic hydrothermal evolution
Chemical Geology, 2019Co-Authors: He Dong Zhao, Kuidong Zhao, Martin R Palmer, Shao Yong JiangAbstract:Abstract Tourmaline often occurs in boron-rich granites and its genesis is still in dispute either formed from residual boron-rich silicate melt or from magmatic hydrothermal fluids with or without external fluid involvement. Here, we present a systematic investigation of in-situ major, trace elemental and boron isotopic variations of Tourmaline from the Sanfang granite in Guangxi Province of South China, which demonstrate both the magmatic and hydrothermal origin for the formation of the Tourmalines. The Tourmaline occurs mainly in quartz-Tourmaline nodules and Tourmaline pegmatitic segregations within the Sanfang granite. Four types of Tourmaline are identified: (1) isolated and disseminated Tourmaline (Tur-D type) distributed in granite; (2) euhedral and subhedral Tourmaline in quartz-Tourmaline nodules (Tur-N type); (3) the earlier stage Tourmaline (Tur-PE type) in pegmatitic segregations and (4) the later stage Tourmaline (Tur-PL type) which replaced the Tur-PE type Tourmaline in pegmatitic segregations. All the Tourmalines belong to the alkali group representing dravite-schorl solid solution series with the former three types being schorl and the Tur-PL type being dravite. Petrography, chemical discrimination diagrams and Al occupations in the Y-site suggest that the Tur-D, Tur-N and Tur-PE type Tourmalines are of magmatic origin and the Tur-PL type Tourmalines are of hydrothermal fluid origin. Elemental and boron isotopic composition variations of Tourmalines reflect the compositional and environmental evolution from late boron-rich magma to exsolved hydrothermal fluids. Chemical variations from the Tur-D to the Tur-N Tourmalines are controlled by magma differentiation. The increase of Mg/(Mg + Fe) and Ca/(Ca + Na) ratios from the Tur-N to the Tur-PE Tourmalines suggests the contamination of surrounding strata (e.g. the Sibao Group). Hydrothermal Tourmalines have higher Mg/(Mg + Fe) and lower Na/(Na + Ca) ratios than the magmatic Tourmalines. There is clear correlation at least in some trace elements (e.g. Sr, Pb) with major elements for all Tourmalines, indicating the potential crystal chemical effects on their incorporation. Other trace element incorporation in Tourmaline is largely controlled by melt and fluid composition. Hydrothermal Tourmalines have high and stable V, Co and Ni contents, indicating relatively constant partition coefficient between hydrothermal Tourmalines and the fluid. Hydrothermal Tourmalines exhibit lower total REE contents but more pronounced positive Eu anomalies than the magmatic Tourmalines. The δ11B values of all Tourmalines from the Sanfang granite vary from −14.4‰ to −9.3‰, which indicate the boron in the Sanfang granite was mainly derived from partial melting of the metasedimentary source rocks. Boron isotopic variations of Tourmaline are controlled by fractionation between melt-fluid and Rayleigh fractionation.
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chemical and textural features of Tourmaline from the spodumene subtype koktokay no 3 pegmatite altai northwestern china a record of magmatic to hydrothermal evolution
Canadian Mineralogist, 2008Co-Authors: Aicheng Zhang, Rucheng Wang, Shao Yong Jiang, Hui ZhangAbstract:The Koktokay No. 3 pegmatite, Altai, northwestern China, is a spodumene-subtype granitic pegmatite. In this study, we report textural and chemical features of Tourmaline from the altered country-rock, the contact zone, and the pegmatite. The Tourmaline ill the altered country-rock, Ca- and Fe-rich dravite, shows an obvious chemical heterogeneity within individual grains. Tourmaline in the contact zone consists of two generations: zoned Ca- and Fe-rich dravite and in interstitial foitite-schorl solid solution. Tourmaline from the altered country-rock and the contact zone reflects interaction between the country rock (metagabbro) and the pegmatite-forming melt or fluids derived from it. The chemical variation of these Tourmalines depends on various contributions of components from the country rock and the pegmatite. The Tourmaline in the outer zones (zones I to IV) of the pegmatite is elbaite-schorl solid solution with all intermediate composition between the end members; it is generally homogeneous within individual grains. In the inner zones (zones V, VI, and VIII), the Tourmaline is dominantly elbaite with rare rossmanite in zone V. Elbaite is either abruptly zoned within individual grains, or has a replacement texture. Chemically, elbaite in the inner zones has a higher proportion of X-site vacancy than elbaite-schorl in the outer zones. Chemical trends of Tourmaline compositions in the spodumene-subtype Koktokay No. 3 pegmatite are generally similar to those in other pegmatite subtypes (lepidolite, petalite, and elbaite subtype). Systematic variations in the internal textures of Tourmaline from the outer zones to the inner zones suggest that exsolution of fluids occurred between zone IV and zone V. The outer zones crystallized from a volatile-unsaturated pegmatite-forming magma, whereas the inner zones crystallized from a hydrothermal system. This evolution process is consistent with the London model of internal evolution of granitic pegmatites.
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petrographic chemical and b isotopic insights into the origin of Tourmaline rich rocks and boron recycling in the martinamor antiform central iberian zone salamanca spain
Journal of Petrology, 2005Co-Authors: Alfonso Pesquera, Jose Torresruiz, Pedro P Gilcrespo, Shao Yong JiangAbstract:Tourmaline in the Martinamor antiform occurs in tourmalinites (rocks with >15–20% Tourmaline by volume), clastic metasedimentary rocks of the Upper Proterozoic Monterrubio formation, quartz veins, pre-Variscan orthogneisses and Variscan granitic rocks. Petrographic observations, back-scattered electron (BSE) images, and microprobe data document a multistaged development of Tourmaline. Overall, variations in the Mg/(Mg þ Fe) ratios decrease from tourmalinites (0 36–0 75), through veins (0 38–0 66) to granitic rocks (0 23–0 46), whereas Al increases in the same order from 5 84–6 65 to 6 22–6 88 apfu. The incorporation of Al into Tourmaline is consistent with combinations of cAl(NaR)–1 and AlO(R(OH))–1 exchange vectors, where c represents X-site vacancy and R is (Mg þ Fe2þ þ Mn). Variations in c/( c þ Na) ratios are similar in all the types of Tourmaline occurrences, from 0 10 to 0 53, with low Ca-contents (mostly <0 10 apfu). Based on field and textural criteria, two groups of Tourmaline-rich rocks are distinguished: (1) pre-Variscan tourmalinites (probably Cadomian), affected by both deformation and regional metamorphism during the Variscan orogeny; (2) tourmalinites related to the synkinematic granitic complex of Martinamor. Textural and geochemical data are consistent with a psammopelitic parentage for the protolith of the tourmalinites. Boron isotope analyses of Tourmaline have a total range of dB values from 15 6 to 6 8%; the lowest corresponding to granitic Tourmalines ( 15 6 to 11 7%) and the highest to veins (1 9 to 6 8%). Tourmalines from tourmalinites have intermediate dB values of 8 0 to þ2 0%. The observed variations in dB support an important crustal recycling of boron in the Martinamor area, in which pre-Variscan tourmalinites were remobilized by a combination of mechanical and chemical processes during Variscan deformation, metamorphism and anatexis, leading to the formation of multiple Tourmaline-bearing veins and a new stage of boron metasomatism.
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trace and rare earth element geochemistry in Tourmaline and cassiterite from the yunlong tin deposit yunnan china implication for migmatitic hydrothermal fluid evolution and ore genesis
Chemical Geology, 2004Co-Authors: Shao Yong JiangAbstract:Abstract Yunlong tin deposit is a medial-sized hydrothermal deposit in western Yunnan province of China. This deposit is unusual because the tin mineralization occurs exclusively within the migmatite bodies. The genesis of the ore deposit has been hotly debated and various models have been proposed including granite-related magmatic–hydrothermal and migmatitic–hydrothermal origins. This paper reports a systematic trace and rare-earth elements (REE) geochemical study in Tourmaline and cassiterite from the orebodies and associated migmatites from the Yunlong tin deposit. Tourmaline and cassiterite from this deposit show light REE (LREE)-enriched patterns with variable Eu and Ce anomalies consistent with hydrothermal fluids being derived from local high-grade metamorphism and migmatization. The data suggest that Tourmaline and cassiterite were likely precipitated from migmatitic–hydrothermal fluids and indicate that the Yunlong tin deposit was probably formed during migmatitic–hydrothermal process. The high concentrations of transition metals (e.g., Sc, Ti, V, Cr, Mn, and Zn) in Tourmalines are also consistent with this model. The high concentrations of Sn, Sr, and especially Sc, V, and Cr in Tourmalines can be used to discriminate Tourmaline from barren deposits relative to those associated with economic tin mineralization.
R. B. Trumbull - One of the best experts on this subject based on the ideXlab platform.
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chemical and boron isotopic composition of hydrothermal Tourmaline from the panasqueira w sn cu deposit portugal
Chemical Geology, 2017Co-Authors: Marta S Codeco, R. B. Trumbull, Philipp Weis, Filipe Pinto, Pilar Lecumberrisanchez, Franziska D H WilkeAbstract:Abstract Tourmaline is a locally abundant hydrothermal mineral in the wallrocks surrounding the W-Sn-Cu mineralized veins in the Panasqueira deposit (Portugal) and a minor phase within the veins themselves. Tourmaline chemical and boron-isotope compositions have been determined from three settings: (1) pervasive fine-grained tourmalinization zones in wallrocks within 10 cm of the veins, (2) coarser Tourmaline in wallrock-hosted fault zones, and (3) needle-shaped Tourmaline from late-stage vugs in the quartz veins. All Tourmalines from Panasqueira have ferromagnesian compositions with significant octahedral aluminum contents and variable X-site vacancies. Tourmaline compositions show significant chemical variations at the grain and sample scale but are homogeneous on the deposit scale. Tourmaline is typically optically and chemically zoned, showing significant increases in Fe and F and decrease in Mg, Ca and Al from core to rim. Moreover, as a general trend, Al increases and Mg decreases with proximity to the vein contact. The observed chemical variation seems to have been controlled mainly by the vectors: FeMg−1; X□AlNa−1(R2+)−1; X□Al(OH)Na−1(R2+)−1F−1; R2+(OH,F)Al−1O−1 and X□Al2O Na−1(R2+)−2(OH,F)−1. The total range in Tourmaline δ11B values from the Panasqueira W-Sn-Cu deposit is from −3.7 to −12.7‰, including Tourmaline from the three settings. The calculated B-isotope composition of the hydrothermal fluid based on the average Tourmaline composition of −9‰ and an estimated alteration temperature in the wallrocks, based on Ti-in-quartz thermometry, of 500 °C is −7.1‰. This isotopic composition is permissive of a boron source from local metasediments or an S-type granite, but the high boron concentration in the wallrocks, with > 50 vol% Tourmaline, along with the typical element association of Panasqueira (W, Sn, F, Nb, Ta, Rb) makes a granitic source more likely. Late-stage Tourmaline needles in vugs within the mineralized veins show the same patterns and ranges in both chemical and boron isotope composition, suggesting that exsolved magmatic fluids were injected in at least two pulses. The variations in chemical and boron isotopic compositions of Tourmaline combined with estimates from Ti-in-quartz thermometry suggest that hydrothermal ore formation is associated with fluid cooling and geochemical fluid-rock interactions.
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stable isotope b h o and mineral chemistry constraints on the magmatic to hydrothermal evolution of the varutrask rare element pegmatite northern sweden
Chemical Geology, 2016Co-Authors: Karin Siegel, R. B. Trumbull, Thomas Wagner, Erik Jonsson, Gabriella Matalin, Markus Walle, Christoph A HeinrichAbstract:Abstract The internal evolution of the Varutrask rare-element pegmatite (Skellefte District, Northern Sweden) has been investigated using stable isotope (B, H, O) geochemistry of Tourmaline and coexisting micas, feldspar and quartz. Varutrask is a classic and typical example of highly fractionated LCT-type pegmatites, with a pronounced concentric zoning pattern composed of well-developed border, wall and intermediate zones and a quartz core. The pegmatite displays considerable rare-element enrichment, culminating in the formation of albite-lepidolite and pollucite units in the innermost zones. Major and trace element variations in Tourmaline from the main pegmatite zones correlate well with the internal zoning pattern. Mineral compositions record an abrupt change in fractionation trends between the barren outer and intermediate zones and the inner, late-stage assemblages that carry rare-element mineralization. This change is also shown by the B-isotope variations of Tourmaline. Early and mid-stage Tourmalines record a systematic increase in δ 11 B from − 14.6‰ to − 6.2‰ which can be explained by closed-system melt-mineral isotope fractionation whereby crystallization of large amounts of muscovite preferentially removes 10 B from the residual melt. In contrast, Tourmaline from late-stage assemblages in the inner zones and cross-cutting veinlets shows a reversal in the B isotope trend, with a decrease in δ 11 B from − 8‰ to − 14.1‰. This reversal cannot be explained by mineral-melt isotope fractionation, but requires fluid-melt partitioning and partial fluid loss. Hydrogen isotope variations in mica support this model. The systematic increase in δD from − 75‰ in the outer zones (muscovite) to − 63‰ and − 53‰ in the inner zones (Li-micas) cannot be explained by closed-system variations in temperature or melt-mica fractionation, but it is consistent with late fluid exsolution. Oxygen isotope compositions of Tourmaline (δ 18 O from 9.7‰ to 11.6‰), quartz (13.3‰ to 14‰) and mica (10.3‰ to 11.3‰) show good agreement with equilibrium partitioning and yield temperatures in the range 450 °C to 600 °C. Combining this with the stability fields of Li-aluminosilicates petalite and spodumene indicates crystallization pressures of 2–3 kbar. Taken together, the stable isotope and mineral chemistry data demonstrate that rare-element enrichment in the innermost fractionated assemblages in the Varutrask pegmatite was associated with the transition from purely magmatic crystallization to conditions where a separate aqueous fluid phase became important.
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Tourmaline as a Recorder of Ore-Forming Processes
Elements, 2011Co-Authors: John F Slack, R. B. TrumbullAbstract:Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fluids. Because of its broad range in composition and retention of chemical and isotopic signatures, Tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related Tourmaline provide valuable insights into hydrothermal systems in seafloor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in Tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.
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fluid sources and metallogenesis in the blackbird co cu au bi y ree district idaho u s a insights from major element and boron isotopic compositions of Tourmaline
Canadian Mineralogist, 2011Co-Authors: R. B. Trumbull, John F Slack, M.-s. Krienitz, Harvey E Belkin, Michael WiedenbeckAbstract:Tourmaline is a widespread mineral in the Mesoproterozoic Blackbird Co–Cu–Au–Bi–Y–REE district, Idaho, where it occurs in both mineralized zones and wallrocks. We report here major-element and B-isotope compositions of Tourmaline from stratabound sulfide deposits and their metasedimentary wallrocks, from mineralized and barren pipes of Tourmaline breccia, from late barren quartz veins, and from Mesoproterozoic granite. The Tourmalines are aluminous, intermediate in the schorl–dravite series, with Fe/(Fe + Mg) values of 0.30 to 0.85, and 10 to 50% X -site vacancies. Compositional zoning is prominent only in Tourmaline from breccias and quartz veins; crystal rims are enriched in Mg, Ca and Ti, and depleted in Fe and Al relative to cores. The chemical composition of Tourmaline does not correlate with the presence or absence of mineralization. The δ 11 B values fall into two groups. Isotopically light Tourmaline (−21.7 to −7.6‰) occurs in unmineralized samples from wallrocks, late quartz veins and Mesoproterozoic granite, whereas heavy Tourmaline (−6.9 to +3.2‰) is spatially associated with mineralization (stratabound and breccia-hosted), and is also found in barren breccia. At an inferred temperature of 300°C, boron in the hydrothermal fluid associated with mineralization had δ 11 B values of −3 to +7‰. The high end of this range indicates a marine source of the boron. A likely scenario involves leaching of boron principally from marine carbonate beds or B-bearing evaporites in Mesoproterozoic strata of the region. The δ 11 B values of the isotopically light Tourmaline in the sulfide deposits are attributed to recrystallization during Cretaceous metamorphism, superimposed on a light boron component derived from footwall siliciclastic sediments ( e.g. , marine clays) during Mesoproterozoic mineralization, and possibly a minor component of light boron from a magmatic–hydrothermal fluid. The metal association of Bi–Be–Y–REE in the Blackbird ores suggests some magmatic input, but involvement of granite-derived fluids cannot be conclusively established from the present database.
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chemical and boron isotope compositions of Tourmaline from the jaduguda u cu fe deposit singhbhum shear zone india implications for the sources and evolution of mineralizing fluids
Chemical Geology, 2010Co-Authors: Dipak C Pal, R. B. Trumbull, Michael WiedenbeckAbstract:Abstract The Proterozoic Jaduguda U (–Cu–Fe) deposit in the Singhbhum shear zone, eastern India hosts the oldest and most productive uranium mine in India. The polymetallic ores in Jaduguda are hosted in altered, sheared and metamorphosed volcano-sedimentary rocks, and this complexity has lead to a confusion in ore genetic models for the deposit. A characteristic of the mineralization is the presence of abundant Tourmaline, locally exceeding 50 vol.%, which is spatially associated with U and Cu mineralization in all rock types and its chemical and B-isotopic variations provide important constraints on fluid source(s) and ore deposit affinity. We examined Tourmaline from the U–Cu ore zone and adjacent footwall and hanging wall meta-sedimentary rocks. Tourmaline grew in three different stages. Pre-kinematic Tourmaline-1, represented by fractured and porphyroblastic grains, is ubiquitous in the wall rocks and the U–Cu zone. Syn-kinematic Tourmaline-2 and post-kinematic Tourmaline-3 are found exclusively in the U–Cu zone, where intense shear deformation has focussed fluid flow, alteration and metamorphism. All Tourmalines belong to the alkalic group and most are dravitic. Systematic contrasts in major element compositions between Tourmaline-1 and Tourmaline-2 are attributed to the influence of high fluid/rock ratios in the U–Cu ore zone. Tourmaline from the Jaduguda deposit exhibits a wide overall range of δ11B values from − 6.8 to + 17.2‰. Positive values of Tourmaline-1 are irrespective of host rock and ore association (U or U + Cu), and range between + 2.3 to + 17.2‰ (n = 44). The calculated δ11B values of fluid in equilibrium with this Tourmaline (for mineralization temperatures of 300–450 °C) range from ~+4 to ~+20‰. The δ11B values of syn-kinematic Tourmaline-2 are much lower than Tourmaline-1, between − 6.8 and + 4‰ (n = 7) and the corresponding fluid δ11B values are − 4.8 + 6‰. The high values of δ11B for Tourmaline-1 and early fluid suggest a marine evaporite or basinal brine was the source of boron, and this fits with abundant mineralogical and geochemical evidence for highly-saline fluids during mineralization. We propose that the isotopically lighter fluid associated with Tourmaline-2 and related syn-kinematic mineralization/mobilization was derived from the metamorphic volcano-sedimentary rocks at high fluid/rock ratios in and around the shear zone. Post-kinematic Tourmaline-3 is compositionally and isotopically (δ11B = + 4 to + 11.1‰, n = 5) similar to Tourmaline-1 in the same samples, suggesting it formed by local recrystallization of the early Tourmaline or from a renewed influx of saline fluids similar to those which formed the pre-kinematic mineralization. Integrating the results of this Tourmaline study with the geological and geochemical characteristics of the Jaduguda U–(Cu–Fe) mineralization suggests that it is best regarded as a variant of the Fe-oxide (Cu–U–REE) or IOCG class of deposits.
Chaohui Wang - One of the best experts on this subject based on the ideXlab platform.
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environmental effects and enhancement mechanism of graphene Tourmaline composites
Journal of Cleaner Production, 2020Co-Authors: Chaohui Wang, Qian Chen, Qiang LiAbstract:Abstract Through releasing negative ions and infrared radiation, Tourmaline can absorb dust and hazardous substances to purify air. The purpose is to improve the air purification efficiency of Tourmaline through the remarkable electrical properties of graphene. The efficient preparation method of graphene/Tourmaline composite was proposed. The environmental properties of the graphene/Tourmaline composites, such as infrared radiation and negative ion release, were systematically analyzed. The Hall effect was used to reveal the enhancement mechanism of graphene on Tourmaline. This laid a solid foundation for the application of composites in the air purification fields. The results demonstrated that graphene could significantly enhance the environmental effect of Tourmaline. The ball milling method was the optimum preparation method, and the parameters were determined as follows: ball milling speed = 200 rpm and ball milling time = 2 h. The optimum graphene content was 0.5% of the mass of Tourmaline. The negative-ion release performance of graphene/Tourmaline composites was higher than that of Tourmaline by over 11.9%. The infrared emissivity and negative-ion release of graphene/Tourmaline composites were observed to be significantly correlated with the band gap. The main reason for the enhancement in the environmental properties of Tourmaline by graphene was that the band gap of Tourmaline was reduced when graphene was compounded with Tourmaline.
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performance evaluation of Tourmaline modified asphalt mixture based on grey target decision method
Construction and Building Materials, 2019Co-Authors: Qian Chen, Chaohui Wang, Penghui Wen, Xiaolong Sun, Tengteng GuoAbstract:Abstract Tourmaline modified asphalt mixture has the air purification effect and is an excellent low-carbon road material. However, previous studies mainly focused on the improvement of road performance for Tourmaline modified asphalt mixture. There were few studies on its comprehensive performance evaluation. In order to further promote the application of Tourmaline in the field of modified asphalt mixtures, Tourmaline modified asphalt mixture was prepared. The comprehensive performance evaluation system for Tourmaline modified asphalt mixture was established based on the grey target decision method. Based on two mixing methods, the road performance of Tourmaline modified asphalt mixture were systematically analyzed, the comprehensive performance of Tourmaline modified asphalt mixture was evaluated, the suitable content of Tourmaline in the modified asphalt mixture was determined. The results show that the comprehensive performance evaluation system based on grey target decision method has good reliability and practicability. The comprehensive performance of Tourmaline modified asphalt mixture achieves its best with 10% Tourmaline.
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preparation and improved negative ion release of graphene Tourmaline composite
Materials Research Express, 2019Co-Authors: Yaolu Luo, Chaohui Wang, Qian Chen, Tengteng GuoAbstract:The purpose is to further improve the negative ion release of Tourmaline and broaden the application of Tourmaline in the field of environmental protection. The new method for preparing graphene/Tourmaline composite by ball milling was proposed. The optimum preparation process of graphene/Tourmaline composite was determined through microscopic tests. The influence of graphene content on negative ion release of composites at different conditions was studied systematically. The enhancement mechanism of graphene/Tourmaline composite on negative ion release was analyzed. The results show that graphene can significantly enhance negative ion release of Tourmaline. And it is more advantageous to increase negative ion release of graphene/Tourmaline composite by appropriately increasing temperature while adding graphene. The optimum ball milling parameters are determined as ball milling speed of 200 rpm and time of 2 h. Compared with Tourmaline, the graphene/Tourmaline composite has an increase in negative ion release of 11.9%.
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laboratory investigation of dynamic rheological properties of Tourmaline modified bitumen
Construction and Building Materials, 2015Co-Authors: Chaohui Wang, Peng Wang, Yongzhe ZhaoAbstract:Abstract Tourmaline modified bitumen was prepared by blending base bitumen with Tourmaline powder. Effect of temperature, frequency as well as the content of Tourmaline powder on the complex modulus and phase angle of the bitumen was investigated by dynamic shear rheometer (DSR). The results indicate that the complex modulus decreased whereas the phase angle increased with the increasing of temperature and frequency, the complex modulus of modified bitumen exhibit good linear relationship with the logarithmic value of loading frequency. Compared with base bitumen, the bitumen containing Tourmaline powder exhibit higher rutting factor, indicating that the rutting resistance of bitumen at high temperature was improved by Tourmaline, for the rigidity of bitumen was enhanced by Tourmaline.
Michael Wiedenbeck - One of the best experts on this subject based on the ideXlab platform.
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late magmatic immiscibility during batholith formation assessment of b isotopes and trace elements in Tourmaline from the land s end granite sw england
Contributions to Mineralogy and Petrology, 2015Co-Authors: Kristian Drivenes, Michael Wiedenbeck, Rune B Larsen, Axel H E Muller, Bjorn Eske Sorensen, Morten RaanesAbstract:last crystallization, and are significantly higher in Sr and Sn, and isotopically heavier. Tourmaline associated with Sn mineralization is also high in Sr and Sn, but has boron isotopic compositions close to that of the magmatic Tourmaline, and is not formed by the same fluids responsible for the blue overgrowths. The ore-forming fluids precipitating Tourmaline and cassiterite are likely derived from the same magma source as the granite, but exsolved deeper in the magma chamber, and at a later stage than orbicule formation. Tourmaline from massive quartz–Tourmaline rocks is concentrically zoned, with major and trace element compositions indicating crystallization from a similar melt as for the orbicules, but shows a more evolved signature.
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fluid sources and metallogenesis in the blackbird co cu au bi y ree district idaho u s a insights from major element and boron isotopic compositions of Tourmaline
Canadian Mineralogist, 2011Co-Authors: R. B. Trumbull, John F Slack, M.-s. Krienitz, Harvey E Belkin, Michael WiedenbeckAbstract:Tourmaline is a widespread mineral in the Mesoproterozoic Blackbird Co–Cu–Au–Bi–Y–REE district, Idaho, where it occurs in both mineralized zones and wallrocks. We report here major-element and B-isotope compositions of Tourmaline from stratabound sulfide deposits and their metasedimentary wallrocks, from mineralized and barren pipes of Tourmaline breccia, from late barren quartz veins, and from Mesoproterozoic granite. The Tourmalines are aluminous, intermediate in the schorl–dravite series, with Fe/(Fe + Mg) values of 0.30 to 0.85, and 10 to 50% X -site vacancies. Compositional zoning is prominent only in Tourmaline from breccias and quartz veins; crystal rims are enriched in Mg, Ca and Ti, and depleted in Fe and Al relative to cores. The chemical composition of Tourmaline does not correlate with the presence or absence of mineralization. The δ 11 B values fall into two groups. Isotopically light Tourmaline (−21.7 to −7.6‰) occurs in unmineralized samples from wallrocks, late quartz veins and Mesoproterozoic granite, whereas heavy Tourmaline (−6.9 to +3.2‰) is spatially associated with mineralization (stratabound and breccia-hosted), and is also found in barren breccia. At an inferred temperature of 300°C, boron in the hydrothermal fluid associated with mineralization had δ 11 B values of −3 to +7‰. The high end of this range indicates a marine source of the boron. A likely scenario involves leaching of boron principally from marine carbonate beds or B-bearing evaporites in Mesoproterozoic strata of the region. The δ 11 B values of the isotopically light Tourmaline in the sulfide deposits are attributed to recrystallization during Cretaceous metamorphism, superimposed on a light boron component derived from footwall siliciclastic sediments ( e.g. , marine clays) during Mesoproterozoic mineralization, and possibly a minor component of light boron from a magmatic–hydrothermal fluid. The metal association of Bi–Be–Y–REE in the Blackbird ores suggests some magmatic input, but involvement of granite-derived fluids cannot be conclusively established from the present database.
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chemical and boron isotope compositions of Tourmaline from the jaduguda u cu fe deposit singhbhum shear zone india implications for the sources and evolution of mineralizing fluids
Chemical Geology, 2010Co-Authors: Dipak C Pal, R. B. Trumbull, Michael WiedenbeckAbstract:Abstract The Proterozoic Jaduguda U (–Cu–Fe) deposit in the Singhbhum shear zone, eastern India hosts the oldest and most productive uranium mine in India. The polymetallic ores in Jaduguda are hosted in altered, sheared and metamorphosed volcano-sedimentary rocks, and this complexity has lead to a confusion in ore genetic models for the deposit. A characteristic of the mineralization is the presence of abundant Tourmaline, locally exceeding 50 vol.%, which is spatially associated with U and Cu mineralization in all rock types and its chemical and B-isotopic variations provide important constraints on fluid source(s) and ore deposit affinity. We examined Tourmaline from the U–Cu ore zone and adjacent footwall and hanging wall meta-sedimentary rocks. Tourmaline grew in three different stages. Pre-kinematic Tourmaline-1, represented by fractured and porphyroblastic grains, is ubiquitous in the wall rocks and the U–Cu zone. Syn-kinematic Tourmaline-2 and post-kinematic Tourmaline-3 are found exclusively in the U–Cu zone, where intense shear deformation has focussed fluid flow, alteration and metamorphism. All Tourmalines belong to the alkalic group and most are dravitic. Systematic contrasts in major element compositions between Tourmaline-1 and Tourmaline-2 are attributed to the influence of high fluid/rock ratios in the U–Cu ore zone. Tourmaline from the Jaduguda deposit exhibits a wide overall range of δ11B values from − 6.8 to + 17.2‰. Positive values of Tourmaline-1 are irrespective of host rock and ore association (U or U + Cu), and range between + 2.3 to + 17.2‰ (n = 44). The calculated δ11B values of fluid in equilibrium with this Tourmaline (for mineralization temperatures of 300–450 °C) range from ~+4 to ~+20‰. The δ11B values of syn-kinematic Tourmaline-2 are much lower than Tourmaline-1, between − 6.8 and + 4‰ (n = 7) and the corresponding fluid δ11B values are − 4.8 + 6‰. The high values of δ11B for Tourmaline-1 and early fluid suggest a marine evaporite or basinal brine was the source of boron, and this fits with abundant mineralogical and geochemical evidence for highly-saline fluids during mineralization. We propose that the isotopically lighter fluid associated with Tourmaline-2 and related syn-kinematic mineralization/mobilization was derived from the metamorphic volcano-sedimentary rocks at high fluid/rock ratios in and around the shear zone. Post-kinematic Tourmaline-3 is compositionally and isotopically (δ11B = + 4 to + 11.1‰, n = 5) similar to Tourmaline-1 in the same samples, suggesting it formed by local recrystallization of the early Tourmaline or from a renewed influx of saline fluids similar to those which formed the pre-kinematic mineralization. Integrating the results of this Tourmaline study with the geological and geochemical characteristics of the Jaduguda U–(Cu–Fe) mineralization suggests that it is best regarded as a variant of the Fe-oxide (Cu–U–REE) or IOCG class of deposits.
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boron isotopes in the puga geothermal system india and their implications for the habitat of early life
Astrobiology, 2019Co-Authors: Luke Steller, Eizo Nakamura, Tsutomu Ota, Chie Sakaguchi, Mukund Sharma, Martin J Van KranendonkAbstract:Abstract Boron is associated with several Archean stromatolite deposits, including the Tourmaline-rich Barberton stromatolites in South Africa and Tourmaline-bearing pyritic laminae associated with...
