Journal of Metamorphic Geology最新文献

{"title":"Implications of garnet nucleation overstepping for the P–T evolution of the Lesser Himalayan Sequence of central Nepal","authors":"Shashi Tamang,&nbsp;Chiara Groppo,&nbsp;Frédéric Girault,&nbsp;Franco Rolfo","doi":"10.1111/jmg.12695","DOIUrl":"10.1111/jmg.12695","url":null,"abstract":"<p>Recent studies have demonstrated that kinetic factors can significantly influence garnet nucleation, delaying its appearance with respect to the equilibrium predictions. Overstepping of garnet nucleation occurs in both contact and regional metamorphic settings, with extremely variable degrees: The factors controlling such highly variable degrees of overstepping are still unclear. This study focuses on garnet nucleation and growth in aluminous metapelites from the Barrovian inverted metamorphic pile of the upper portion of the Lesser Himalayan Sequence (Upper-LHS; central Nepal), with the aim of (i) investigating if (and how) the bulk-rock composition can influence overstepping of garnet nucleation and (ii) which are the implications of garnet nucleation overstepping for the P–T evolution of a Barrovian metamorphic sequence. Detailed petrographic, microstructural and compositional data are presented for six phyllitic schists, containing porphyroblasts of garnet, staurolite and/or kyanite. Their P–T evolution is constrained through thermodynamic forward modelling (i.e., isochemical phase diagrams combined with isopleth thermobarometry), assuming that equilibrium was attained at every stage of their metamorphic evolution. Comparison between the P–T conditions inferred for the growth of garnet core, the assemblages predicted to be stable at these P–T conditions and the modelled garnet-in reaction boundary suggests that the studied samples have experienced different degrees of apparent thermal (ΔT) and/or baric (ΔP) overstepping of garnet nucleation. We suggest that the bulk-rock MnO and CaO amounts might have influenced the apparent ΔT and ΔP overstepping of the garnet-in reaction: more specifically, the higher the bulk-rock MnO content, the more pronounced the apparent ΔT overstepping, whereas the lower the bulk-rock CaO content, the greater the ΔP overstepping. However, rather than an effective delay of garnet appearance with respect to equilibrium predictions, the apparent ΔT overstepping of garnet nucleation could reflect the attainment of the critical 0.5% threshold of garnet abundance, below which garnet is not readily detected in thin section. Kinetic factors seem much less critical in controlling the growth of the garnet rim at peak P–T conditions, confirming that peak metamorphic conditions constrained through equilibrium approaches based on the composition of garnet rim and of the matrix assemblage can be considered as reliable. Overall, the P–T paths of the studied samples are characterized by prograde heating coupled with tectonic overload (peak-P conditions of 9.5–10.5 kbar, 580–590°C), followed by heating during exhumation (peak-T conditions of 8.2–8.9 kbar, 610–630°C), supporting those thermo-mechanical models that predict a period of slowdown (or quiescence) of the Main Central Thrust activity.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 2","pages":"271-297"},"PeriodicalIF":3.4,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49146471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the tectonometamorphic history of subducted metapelites using quartz-in-garnet and Ti-in-quartz (QuiG–TiQ) geothermobarometry—A key for understanding burial in the Scandinavian Caledonides","authors":"Pauline Jeanneret,&nbsp;Iwona Klonowska,&nbsp;Christopher Barnes,&nbsp;Jarosław Majka,&nbsp;Johanna Holmberg,&nbsp;Mattia Gilio,&nbsp;William Nachlas,&nbsp;Matteo Alvaro,&nbsp;Karolina Kośmińska,&nbsp;Henning Lorenz,&nbsp;Thomas Zack,&nbsp;Anna Ladenberger,&nbsp;Hemin Koyi","doi":"10.1111/jmg.12693","DOIUrl":"10.1111/jmg.12693","url":null,"abstract":"&lt;p&gt;The Seve Nappe Complex is a subduction-related high-grade metamorphic unit that was emplaced onto the margin of Baltica during Caledonian orogenesis. In this paper, the tectonometamorphic evolution of the Lower Seve Nappe in the Scandinavian Caledonides was characterized with the help of the continuous Collisional Orogeny in the Scandinavian Caledonides (COSC-1) drill core, using a combination of various P–T estimation techniques based on garnet–quartz mineral pairs (quartz-in-garnet and Ti-in-quartz [QuiG–TiQ]), conventional thermobarometry and thermodynamic modelling of phase equilibria. This multi-method approach yields complementary results and delivers critical data to constrain a comprehensive pressure–temperature–deformation–time (P–T–D–t) evolutionary path for the metasedimentary rocks of the Lower Seve Nappe. In the garnetiferous metasedimentary rocks, quartz inclusions in garnet preserve the P–T conditions of three distinct garnet growth stages corresponding to three metamorphic stages Ms1 to Ms3, including prograde and peak metamorphic conditions. Ms1 and Ms2 stages were constrained via quartz inclusions in garnet core and mantle. They are relatively close in the P–T space and could be considered as one single continuous prograde event occurring at epidote–amphibolite facies conditions of 460–520°C and 0.6–0.85 GPa. The growth of the garnet outermost rim defines the Ms3 stage at amphibolite facies conditions of 590–610°C and 1.13–1.18 GPa and corresponds to the peak metamorphic conditions. The microstructural analysis shows that the finite ductile strain pattern of the Lower Seve Nappe results from the superposition of four deformation phases. The initial phase D1 is defined by the S1 foliation that is still preserved as a curved inclusion trail in the garnet core. The D2 phase initiated contemporaneously with garnet core growth and the development of muscovite–biotite–plagioclase S2 foliation. Garnet outermost rim growth marks the end of the prograde path and peak metamorphic conditions. This stage is overprinted by the D3 phase and Ms4 stage associated with the development of the main regional metamorphic and mylonitic fabric S3 associated with C′-type shear bands along the retrograde path. Ms4 stage, which was constrained using traditional thermobarometric techniques, corresponds to the chemical re-equilibration of the metasedimentary minerals and occurred under amphibolite facies conditions at ~570–610°C and 0.78–1.00 GPa. The D3 phase is then generally weakly to strongly overprinted by later lower grade deformation D4 phase at greenschist facies conditions (Ms5). &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar ages of syn-kinematic white mica and biotite indicate that the final stage of the thrusting of the Lower Seve Nappe and thus the timing of its emplacement onto the Offerdal Nappe occurred at c. 423 Ma. Collectively, these results are consistent with previous estimates of the timing and conditions of metamorphism derived from the Lower Se","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 2","pages":"235-270"},"PeriodicalIF":3.4,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmg.12693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48503326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isothermal compression of an eclogite from the Western Gneiss Region (Norway)","authors":"Martin Simon,&nbsp;Pavel Pitra,&nbsp;Philippe Yamato,&nbsp;Marc Poujol","doi":"10.1111/jmg.12692","DOIUrl":"10.1111/jmg.12692","url":null,"abstract":"<p>In the Western Gneiss Region in Norway, mafic eclogites form lenses within granitoid orthogneiss and contain the best record of the pressure and temperature evolution of this ultrahigh-pressure (UHP) terrane. Their exhumation from the UHP conditions has been extensively studied, but their prograde evolution has been rarely quantified although it represents a key constraint for the tectonic history of this area. This study focused on a well-preserved phengite-bearing eclogite sample from the Nordfjord region. The sample was investigated using phase-equilibrium modelling, trace-element analyses of garnet, trace- and major-element thermobarometry and quartz-in-garnet barometry by Raman spectroscopy. Inclusions in garnet core point to crystallization conditions in the amphibolite facies at 510–600°C and 11–16 kbar, whereas chemical zoning in garnet suggests growth during isothermal compression up to the peak pressure of 28 kbar at 600°C, followed by near-isobaric heating to 660–680°C. Near-isothermal decompression to 10–14 kbar is recorded in fine-grained clinopyroxene–amphibole–plagioclase symplectites. The absence of a temperature increase during compression seems incompatible with the classic view of crystallization along a geothermal gradient in a subduction zone and may question the tectonic significance of eclogite facies metamorphism. Two end-member tectonic scenarios are proposed to explain such an isothermal compression: Either (1) the mafic rocks were originally at depth within the lower crust and were consecutively buried along the isothermal portion of the subducting slab or (2) the mafic rocks recorded up to 14 kbar of tectonic overpressure at constant depth and temperature during the collisional stage of the orogeny.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"181-203"},"PeriodicalIF":3.4,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46410956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal pulse induced by emplacement of Ramba leucogranites in southern Tibet","authors":"Xu Chu,&nbsp;Ozan Akça,&nbsp;Fred Gaidies,&nbsp;Ivano Gennaro,&nbsp;Weiqiang Ji","doi":"10.1111/jmg.12690","DOIUrl":"10.1111/jmg.12690","url":null,"abstract":"<p>The thermal histories of Himalayan leucogranites provide critical information for unravelling the post-collisional geodynamics of the Himalayas. The Ramba Dome is located at the intersection of the Tethyan Himalayan leucogranite belt with the Yadong–Gulu Rift and hosts several generations of granitic intrusions. Of these intrusions, the 8-Ma two-mica granites and garnet leucogranite dykes are the youngest of Himalayan leucogranites. In this study, we focus on the carbonaceous staurolite schist located ~1.3 km from the intrusion to constrain the thermal history of the aureole that marked the cessation of leucogranite magmatism. The schist contains euhedral garnet and staurolite porphyroblasts in a foliated matrix of muscovite + biotite + chlorite + plagioclase + quartz + graphite. The staurolite shows minor compositional variations from the inclusion-free core to the inclusion-rich rim. By contrast, the garnet features a distinctive bell-shaped Mn profile and increasing Mg# from the garnet core to rims. In a graphite-bearing equilibrium phase diagram for a modified bulk composition with garnet cores removed, the garnet rim composition suggests a peak temperature of ~550°C, consistent with an independent thermometer based on the Raman spectra of carbonaceous materials (RSCM; 548 ± 9°C). The P–T condition lies within the narrow low-variance field bracketed by the staurolite-in and chlorite-out boundaries, indicating minimal overstepping of staurolite nucleation and growth. On the other hand, the garnet core composition indicates 520°C at 2.5 kbar, about 40°C higher than the predicted garnet-in boundary (~480°C). This apparent temperature overstep corresponds to a small chemical affinity (&lt;5 kJ/mol 12 O) for garnet nucleation, comparable to previous estimates. The sharp boundaries of the high-Ca sector zoning in the core indicate limited diffusion modification (~1.5 Ma if at the peak temperature). The short thermal pulse involves advective heat transfer by leucogranite emplacement, followed by rapid cooling toward the end of Himalayan magmatism and rapid exhumation likely facilitated by the Yadong–Gulu Rift.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"121-141"},"PeriodicalIF":3.4,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46321107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significance of selective crystal entrainment and differential crystal-melt separation in petrogenesis of granites from the Tongbai orogen","authors":"Qiang-Qiang Zhang,&nbsp;Xiao-Ying Gao,&nbsp;Yong-Fei Zheng","doi":"10.1111/jmg.12691","DOIUrl":"10.1111/jmg.12691","url":null,"abstract":"&lt;p&gt;Partial melting has been shown to be an important mechanism for intracrustal differentiation and granite petrogenesis. However, a series of compositional differences between granitic melt from experiments and natural granites indicate that the processes of crustal differentiation are complex. To shed light on factors that control the processes of crustal differentiation, and then the compositions of granitic magma, a combined study of petrology and geochemistry was carried out for granites (in the forms of granitic veins and parautochthonous granite) from a granulite terrane in the Tongbai orogen, China. These granites are characterized by high SiO&lt;sub&gt;2&lt;/sub&gt; (&gt;72 wt%) and low FeO and MgO (&lt;4 wt%) with low Na&lt;sub&gt;2&lt;/sub&gt;O/K&lt;sub&gt;2&lt;/sub&gt;O ratios (&lt;0.7). Minerals in these granites show variable microstructures and compositions. Phase equilibrium modelling using P–T pseudosections shows that neither anatectic melts nor fractionated melts match the compositions of the target granites, challenging the conventional paradigm that granites are the crystallized product of pure granitic melts. Based on the microstructural features of minerals in the granites, and a comparison of their compositions with crystallized minerals from anatectic melts and minerals in granulites, the minerals in these granitoids are considered to have three origins. The first is entrained garnets, which show comparable compositions with those in host granulites. The second is early crystallized mineral from melts, which include large plagioclase and K-feldspar (with high Ca contents) crystals as well as a part of biotite whose compositions can be reproduced by crystallization of the anatectic melts. The compositions of other minerals such as small grained plagioclase, K-feldspar and anorthoclase in the granites with low Ca contents are not well reconstructed, so they are considered as the third origin of crystallized products of fractionated melts. The results of mass balance calculation show that the compositions of these granites can be produced by mixing between different proportions of crystallized minerals and fractionated melts with variable amounts of entrained minerals. However, the calculated modal proportions of different crystallized minerals (plagioclase, K-feldspar, biotite and quartz) in the granites are significantly different from those predicted by melt crystallization modelling. Specifically, some rocks have lower modes of biotite and plagioclase, whereas others show lower K-feldspar modes than those produced by melt crystallization. This indicates that the crystallized minerals would be differentially separated from the primary magmas to form the evolved magmas that produce these granites. Therefore, the crystal entrainment and differential melt-crystal separation make important contributions to the composition of the target granites. Compared with leucogranites worldwide, the target granites show comparable compositions. As such, the leucogranites m","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"143-179"},"PeriodicalIF":3.4,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44419884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low temperature eclogite facies rocks discovered in the Eastern Himalayan Syntaxis: Poly-cyclic metamorphic evolution and implications","authors":"Wangchao Li,&nbsp;Changqing Yin,&nbsp;Zeming Zhang,&nbsp;Peter A. Cawood,&nbsp;Shun Li,&nbsp;Jian Zhang,&nbsp;Huixia Ding,&nbsp;Jiahui Qian,&nbsp;Yanling Zhang","doi":"10.1111/jmg.12689","DOIUrl":"10.1111/jmg.12689","url":null,"abstract":"<p>We report the first occurrence of poly-cyclic high-pressure low-temperature (HP-LT) rocks from the easternmost Indus-Yarlung suture zone, formed during subduction of Neo-Tethyan oceanic lithosphere. Petrology, mineral composition and P–T pseudosection modelling reveal two low-temperature eclogite facies metamorphic events with an initial high-pressure P–T condition of 16.4–18.7 kbar and 510–520°C, exhumation to 10.5–12.0 kbar and 580–590°C and a subsequent second high-pressure P–T condition of ~16 kbar and ~560°C and exhumation to ≤9 kbar and ≤600°C. This history implies a complex ‘yo-yo type’ P–T path. In situ monazite dating and textural relationships show that late-stage exhumation, cooling and garnet breakdown occurred at c. ~25–22 Ma. We interpret the first burial event to represent subduction of the Neo-Tethys Ocean at the eastern Indus-Yarlung suture zone. Initial exhumation, reburial and final exhumation represent material transport in a large-scale convective circulation system in the subduction channel. Convective overturn in the subduction channel evidently serves both as a mechanism to produce poly-cyclic metamorphism and to exhume LT eclogite facies rocks.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"97-119"},"PeriodicalIF":3.4,"publicationDate":"2022-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43854787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"P–T–t–D records of Early Palaeozoic Andean-type shortening of a hot active margin: The Dunhuang block in NW China","authors":"Jérémie Soldner,&nbsp;Pavla Štípská,&nbsp;Karel Schulmann,&nbsp;Chao Yuan,&nbsp;Robert Anczkiewicz,&nbsp;Yingde Jiang,&nbsp;Marta Koziarska,&nbsp;Le Zhang,&nbsp;Yunying Zhang,&nbsp;Xinyu Wang","doi":"10.1111/jmg.12688","DOIUrl":"10.1111/jmg.12688","url":null,"abstract":"&lt;p&gt;High-pressure (H&lt;i&gt;P&lt;/i&gt;) granulites form either in the domain of the subducted plate during continental collision or in supra-subduction systems where the thermally softened upper plate is shortened and thickened. Such a discrepancy in tectonic setting can be evaluated by metamorphic pressure–temperature–time-deformation (&lt;i&gt;P–T–t–D&lt;/i&gt;) paths. In the current study, &lt;i&gt;P–T–t–D&lt;/i&gt; paths of Early Palaeozoic H&lt;i&gt;P&lt;/i&gt; granulite facies rocks, in the form of metabasic lenses enclosed in migmatitic metapelite, from the Dunhuang block, NW China, are investigated in order to constrain the nature of the H&lt;i&gt;P&lt;/i&gt; rocks and shed light on the geodynamic evolution of a modern hot orogenic system in an active margin setting. The rocks show a polyphase evolution characterized by (1) relics of horizontal or gently dipping fabric (S1) preserved in cores of granulite lenses and in garnet porphyroblasts, (2) a N-S trending sub-vertical fabric (S2) preserved in low-strain domains and (3) upright folds (F3) associated with a ubiquitous steep E-W striking axial planar foliation (S3). Garnet in the granulites preserves relics of a prograde mineral assemblage M1a equilibrated at ~11.5 kbar and ~770–780°C, whereas the matrix granulite assemblage (M1b) from the S1 fabric attained peak pressure at ~13.5 kbar and ~850°C. The granulites were overprinted at ~8–11 kbar and ~850–900°C during crustal melting (M2) followed by partial re-equilibration (M3) at ~8 kbar and ~625°C. A garnet Lu–Hf age of 421.6 ± 1.2 Ma dates metamorphism M1, while a garnet Sm–Nd age of 385.3 ± 4.0 Ma reflects M3 cooling of the granulites. The mineral assemblage, M1, of the host migmatitic metapelite formed at ~9–12.5 kbar and ~760–810°C, partial melting and migmatization (M2) occurred at ~7 kbar and ~760°C and re-equilibration (M3) at ~5–6 kbar and ~675°C. A garnet Lu–Hf age of 409.7 ± 2.3 Ma dates thermal climax (M2) and a garnet Sm–Nd age of 356 ± 11 Ma constrains M3 for the migmatitic metapelites. The timing of this late phase is also bracketed by an emplacement age of syntectonic granite dated at c. 360 Ma. Decoupling of M1 and M2 &lt;i&gt;P–T&lt;/i&gt; evolutions between the mafic granulites and migmatitic metapelites indicates their different positions in the crustal column, while the shared pressure–temperature (&lt;i&gt;P–T&lt;/i&gt;) evolution M3 suggests formation of a mélange-like association during the late stages of orogeny. The high-pressure event D1-M1 is interpreted as a result of Late Silurian–Early Devonian moderate crustal thickening of a thermally softened and thinned pre-orogenic crust. The high-temperature (H&lt;i&gt;T&lt;/i&gt;) re-equilibration D2-M2 is interpreted as a result of Mid-Devonian shortening of the previously thickened crust, possibly due to ‘Andean-type’ underthrusting. The D3-M3 event reflects Late Devonian supra-subduction shortening and continuous erosion of the sub-crustal lithosphere. This tectono-metamorphic sequence of events is explained by polyphased Andean-type deformation of a ‘Casca","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"59-96"},"PeriodicalIF":3.4,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48137191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Social Satisfaction and Living Alone: Predictors of Self-Perception of Mental Health Improvement After Psychosis.","authors":"Patricia R Turner, Emily R Saeteurn","doi":"10.1093/schizbullopen/sgac052","DOIUrl":"10.1093/schizbullopen/sgac052","url":null,"abstract":"<p><strong>Background: </strong>Psychosis recovery can accompany social and self-stigma for the survivor, which can interfere with the person reaching their personal recovery goals. We hypothesized that there would be a strong association between social satisfaction and self-perceived mental health improvement, and that living alone would be a risk factor to self-perceived improvement.</p><p><strong>Study design: </strong>Our strengths-based quantitative study aims to identify the most important factors to psychosis survivors for their mental health recovery. Survey responses from wave 5 of the Population Assessment of Tobacco and Health (PATH) study were used, specifically from those who self-identified as psychosis survivors (<i>n</i> = 710), analyzing the association between self-reported mental health symptoms, social satisfaction changes in the last year, living alone, and demographic variables, with self-reported mental health recovery in the last year.</p><p><strong>Study results: </strong>Ordinary least squares regression analysis revealed three predictors of self-reported mental health improvement for psychosis survivors: social satisfaction, living alone, and lower anxiety. As hypothesized, social satisfaction was the largest determinant in self-perceived mental health improvement, but contrary to our hypothesis, living alone was a protective factor.</p><p><strong>Conclusion: </strong>Prioritizing social satisfaction over group living environments for people recovering after psychosis.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"36 1","pages":"sgac052"},"PeriodicalIF":0.0,"publicationDate":"2022-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11249963/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85981622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HTLP metamorphism and fluid-fluxed melting during multistage anatexis of continental crust (N Sardinia, Italy)","authors":"Leonardo Casini,&nbsp;Matteo Maino,&nbsp;Antonio Langone,&nbsp;Giacomo Oggiano,&nbsp;Stefania Corvò,&nbsp;Joan Reche Estrada,&nbsp;Montserrat Liesa","doi":"10.1111/jmg.12687","DOIUrl":"10.1111/jmg.12687","url":null,"abstract":"<p>The Variscan high-grade metamorphic basement of northern Sardinia and southern Corsica record lower Carboniferous anatexis related to post-collisional decompression of the orogen. Migmatites exposed in the Punta Bianca locality (Italy) consist of quartz + biotite + plagioclase + K-feldspar orthogneisses, garnet and cordierite-bearing diatexite and metatexites, derived from metasediments. Field evidence, petrographic observations, ELA-ICP-MS zircon and monazite dating and pseudosection modelling suggest that anatexis was apparently episodic involving two main stages of partial melting. Using pseudosection modelling, we infer that the first stage of partial melting is in the upper amphibolite facies (~0.45 GPa at ~740°C). Cordierite overgrowths replacing sillimanite, combined with the composition of plagioclase and K-feldspar, suggest decompression followed cooling below the solidus at low pressures of ~0.3 GPa. The age of the first anatectic event is not precisely constrained because of extensive resetting of the isotopic systems during the second melting stage, yet few zircons preserve a lower Carboniferous age which is consistent with the regional dataset. This lower Carboniferous migmatitic fabric is offset by a network of pseudotachylyte-bearing faults suggestive of cooling to greenschist facies conditions. Garnet/cordierite-bearing diatexites incorporate fragments of pseudotachylite-bearing orthogneiss and metatexites. Pseudosection modelling indicates nearly isobaric re-heating up to ~750°C, followed by further cooling below the solidus. The inferred <i>P–T</i> path is consistent with decompression and cooling of the Variscan crust through post-collisional extension and collapse of the thickened orogenic crust, followed by nearly isobaric re-heating at low pressures (~0.3 GPa) yielding to a second melting stage under <i>LP-HT</i> conditions. U/Th-Pb monazite ages for diatexite migmatites indicate an upper bound of 310–316 Ma for the second melting stage, suggesting that the second melting stage is coincident with the regional phase of crustal shearing. The cause of the high geothermal gradient required for re-heating during the second melting stage is unknown but likely requires some heat source that was probably related to dissipation of mechanical work within crustal-scale shear zones. According to this interpretation, some upper Carboniferous peraluminous granite precursors of the Corsica–Sardinia Batholith could be the outcome rather than the cause of the late-Variscan high-T metamorphism.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"25-57"},"PeriodicalIF":3.4,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmg.12687","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47426088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace-element heterogeneity in rutile linked to dislocation structures: Implications for Zr-in-rutile geothermometry","authors":"Rick Verberne,&nbsp;Hugo W. van Schrojenstein Lantman,&nbsp;Steven M. Reddy,&nbsp;Matteo Alvaro,&nbsp;David Wallis,&nbsp;Denis Fougerouse,&nbsp;Antonio Langone,&nbsp;David W. Saxey,&nbsp;William D. A. Rickard","doi":"10.1111/jmg.12686","DOIUrl":"10.1111/jmg.12686","url":null,"abstract":"<p>The trace-element composition of rutile is commonly used to constrain <i>P</i>–<i>T</i>–<i>t</i> conditions for a wide range of metamorphic systems. However, recent studies have demonstrated the redistribution of trace elements in rutile via high-diffusivity pathways and dislocation-impurity associations related to the formation and evolution of microstructures. Here, we investigate trace-element migration in low-angle boundaries formed by dislocation creep in rutile within an omphacite vein of the Lago di Cignana unit (Western Alps, Italy). Zr-in-rutile thermometry and inclusions of quartz in rutile and of coesite in omphacite constrain the conditions of rutile deformation to around the prograde boundary from high pressure to ultra-high pressure (~2.7 GPa) at temperatures of 500–565°C. Crystal-plastic deformation of a large rutile grain results in low-angle boundaries that generate a total misorientation of ~25°. Dislocations constituting one of these low-angle boundaries are enriched in common and uncommon trace elements, including Fe and Ca, providing evidence for the diffusion and trapping of trace elements along the dislocation cores. The role of dislocation microstructures as fast-diffusion pathways must be evaluated when applying high-resolution analytical procedures as compositional disturbances might lead to erroneous interpretations for Ca and Fe. In contrast, our results indicate a trapping mechanism for Zr.</p>","PeriodicalId":16472,"journal":{"name":"Journal of Metamorphic Geology","volume":"41 1","pages":"3-24"},"PeriodicalIF":3.4,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42846995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}