Major, Trace, and Rare-Earth Element Geochemistry of Nb-V Rich Andradite-Schorlomite-Morimotoite Garnet from Ambadungar-Saidivasan Alkaline Carbonatite Complex, India: Implication for the Role of Hydrothermal Fluid-Induced Metasomatism

In situ major, trace and rare-earth element composition of Ti-rich garnets from Ambadungar-Saidivasan alkaline carbonatite complex (ASACC) are presented to constrain its likely genesis. The garnets are characterized by high andradite (42.7–57.3), schorolomite (22.0–31.0), and morimotoite (15.6–26.5) end members. No distinct chemical zonation is noticed except for minor variations in Ti content. The garnets are enriched in LREE (average 731 ppm) and relatively depleted in HREE (average 186 ppm) and show an M-type first tetrad that leads to a convex upward pattern between Ce and Gd. Mildly positive to no Eu anomalies are observed (Eu/Eu* = 1.06–1.17). The REE patterns (LaN/YbN = 1.11–2.11) are similar to those of garnets from skarn deposits. The presence of tetrad effect in the LREE pattern suggests an active role of metasomatic processes involving hydrothermal fluids during the growth of the garnets. These garnets also contain high Nb (282–2283 ppm) and V (1083–2155 ppm) concentrations, which stand out against the composition of the host rock. Therefore, late-stage metasomatic reactions of earlier formed minerals with hydrothermal fluid enriched in Fe, Si, LREE, Nb, V, and Ti led to the formation of garnet. The primary source for these elements could be magnetite, ilmenite, and pyrochlore present in different varieties of carbonatites in the ASACC, with the required elements being released during their interaction with the hydrothermal fluid. The hydrothermal fluid was likely to be moderately acidic, and having fluoride and sulfate as the primary ligands.

Pyroxenitic xenoliths from southern Scotland and what they tell us.

<p>Late Carboniferous/early Permian mafic volcanic rocks occurring in Scotland carry a broad spectrum of peridotitic and pyroxenitic xenoliths. The latter provide evidence of magmatic processes in the lower crust and the lithospheric mantle. In this study we present textural and compositional data on twenty-eight pyroxenitic xenoliths from six localities from southern Scotland (Midland Valley and Southern Uplands Terranes).</p><p>Most are interpreted as adcumulates (varying in grain size from fine to coarse) although some others are mesocumulates. They include both clinopyroxenites and websterites with variable amounts of olivine; phlogopite is present in only one sample. Cores of greenish clinopyroxene in three of the olivine clinopyroxenites are enveloped by brownish clinopyroxene, while one composite xenolith comprising coarse-grained olivine clinopyroxenite in sharp contact with harzburgite. Five groups, based on textural and mineralogical features were distinguished. Representatives of more than one group can be present in a single locality.</p><p>Most of the samples from the same textural group share similar chemical composition. In general, the clinopyroxenes are Ti,Al-diopside/augite with Mg#=0.74-0.86; where clinopyroxenes are zoned the rims have lower Mg# and higher Al content. The orthopyroxene is an Al (±Cr)-enstatite with Mg#=0.78-0.89, olivine (Fo<sub>76-77</sub>) is relatively NiO-rich (0.16-0.29 wt.%). In clinopyroxenites the pyroxenes are LREE-enriched (La<sub>N</sub>/Lu<sub>N</sub>=1.31-3.17) with convex-upward REE patterns (Sm<sub>N</sub>/Lu<sub>N</sub>=2.48-7.37).</p><p>The temperatures and pressures of clinopyroxene crystallization in most of the clinopyroxenites are 1220-1300°C and 1.08–1.30 GPa (Putirka, 2008), respectively. Only the composite xenolith and the coarse-grained clinopyroxenites recorded higher pressures (1.42 and 1.65-2.03 GPa, respectively). As the Moho beneath S Scotland is located at ~35 km (corresponding to ~1 GPa; Davis et al., 2012), most of the clinopyroxenites are considered to come from the uppermost portions of lithospheric mantle or lowermost continental crust; the coarse-grained clinopyroxenites and the composite xenolith sample lithospheric mantle.</p><p>Clinopyroxenites from the southern Scotland crystallized from alkaline basaltic magmas similar to those that entrained  them. Whilst Downes et al. (2007, 2001) had previously suggested this for clinopyroxenites from Midland Valley localities, our studies show that crystallization of mafic melts was more widespread. Strong chemical and textural variations in the pyroxenites together with relatively constant PT conditions of crystallization suggest that they formed either from melts of slightly different composition, perhaps in response to magma chamber processes such as magma replenishment and/ or mixing. While, the presence of mafic cumulates points to possible crustal underplating beneath S Scotland, the presence of a high-pressure clinopyroxenites and composite clinopyroxenitic-peridotitic xenolith imply that some of the pyroxenites originated in the lithospheric mantle.</p><p>Davis et al. (2012). Geoph.J. Int., 190, 705-725.</p><p>Downes et al., (2007). J. Geol. Soc., 164, 1217-1231.</p><p>Downes et al. (2001). Lithos, 58, 105-124.</p><p>Putirka et al. (2008). Rev. Min. Petr., 69, 61-120.</p><p>This study was funded by Polish National Science Centre to MMM no. DEC-2016/23/B/ST10/01905. EPMA analyses were done within the frame of the Polish-Austrian project WTZ PL/16 and WTZ PL 08/2018.</p><p> </p>

Magma ascent, ponding and mixing in a Middle Triassic plumbing system: clues from clinopyroxene chemical-textural features in the Cima Pape volcano-plutonic complex (Southern Alps, Italy)

<p>Zoned crystals play a fundamental role in modern volcanology as a key to unravel the geometry and the dynamics of plumbing systems. Ancient volcano-plutonic complexes, nowadays exposed at the surface, can sometimes preserve textural-chemical record of such dynamics inside their constituting mineral phases. This is the case of the Cima Pape Middle Triassic complex (Dolomites, Southern Alps), which is composed by a 50 to 300 metres thick gabbroic to monzodioritic sill overlaid by basaltic to trachyandesitic volcanites with high Porphyricity Index (P.I. 43-48 %).</p><p>Volcanites contain a large number of concentric-zoned clinopyroxenes, while intrusive rocks are mostly made up of homogeneous and unzoned crystals. In volcanites, the typical clinopyroxene zoning pattern consists of one or more high-Mg# and high Cr<sub>2</sub>O<sub>3</sub> bands (Mg# 84-91; Cr<sub>2</sub>O<sub>3</sub> up to 1.2 wt%) with variable thickness, formed between cores and rims with relatively lower Mg# and Cr contents (Mg# 70-77; Cr<sub>2</sub>O<sub>3</sub> <0.1 wt%). Chondrite-normalized incompatible element patterns of low-Mg# portions show Nb, Ta, Sr, Zr and Ti negative anomalies and Th-U positive peaks, while high-Mg# bands have a generally more depleted patterns maintaining similar profile. REE patterns in both high-Mg# and low-Mg# domains have a convex-upward shape and La/Yb<sub>N</sub> from 1.3 to 2.1. Thermobarometric calculations reveal that the high-Mg# bands were in equilibrium with a more primitive, hotter and more H<sub>2</sub>O depleted melt (Mg# = 65-70; T = 1130-1150°C; H<sub>2</sub>O = 2.1-2.6 wt%) than cores and rims, which likely formed in a colder, H<sub>2</sub>O-rich evolved melt (Mg# = 43-45; T = 1035-1075°C; H<sub>2</sub>O = 2.6-3.8 wt%). According to our model, a first crystallization stage in a high crystallinity (P.I. almost 50%) “mush-type” system led to the formation of low-Mg# clinopyroxenes (Mg# 70-77) at P of 2-4 kbar. The ascent of one or multiple pulses of primitive, hot, and H<sub>2</sub>O-poor basaltic magmas (Casetta et al., 2020) in the shallower portions of the plumbing system led to the formation of the high-Mg# bands. Later on, re-equilibration of clinopyroxene with the post-mixing melt system resulted in the formation of the low-Mg# rims. Cima Pape products have many textural-chemical similarities with those reported at the active Stromboli volcano, suggesting that they were formed through similar dynamics at comparable T-P conditions (Petrone et al., 2018; Di Stefano et al., 2020). The peculiarity of clinopyroxene texture in Cima Pape rocks allowed us to study the processes occurred in the plumbing system beneath an ancient volcano and offered the opportunity to test the approaches/models currently adopted for active systems.</p><p> </p><p>Casetta, F., et al., 2020. The Variscan subduction inheritance in the Southern Alps Sub-Continental Lithospheric Mantle: Clues from the Middle Triassic shoshonitic magmatism of the Dolomites (NE Italy). Lithos, 105856.</p><p>Di Stefano, F., et al., 2020. Mush cannibalism and disruption recorded by clinopyroxene phenocrysts at Stromboli volcano: New insights from recent 2003–2017 activity. Lithos, 360–361.</p><p>Petrone, C. M., et al., 2018. Rapid mixing and short storage timescale in the magma dynamics of a steady-state volcano. Earth and Planetary Science Letters, 492, 206–221.</p>

Feasibility study of the construction of foundations with a convex upward curved shape of the contact surface

In the article the comparison of the two technologies of foundations: the traditional technology of cast-in-situ solid slab Foundation and the alternative technology foundations with the upward-convex curved shape of the contact surface. The foundation with an upward curved contact surface is a geometrically complex structure consisting of monolithic belts (support contours), united by flat cylindrical shells convex upwards with respect to the ground, made along the curved surface of the soil mass with an undisturbed natural structure. Due to the joint work of monolithic belts and a reinforced concrete shell located in the span of the foundation, made along the curved contact surface of the ground mass, this foundation structure is an alternative to a solid slab foundation. When the support contours are drained under load, the reinforcement of the shell is tensioned, the soil under the shell is compressed and thus the soil is involved in the work, which allows increasing the strength characteristics of the foundation and reducing the overall draft of the building. The author of the article describes the structural and technological features of this type of foundation. Due to the complex geometric shape of the foundation under study, the total labor costs and the duration of the work increase in the construction practice. As part of the study, two types of foundations were compared according to technological and economic indicators, using the example with the specified geometric parameters. As a result of the obtained data, an increase in labor costs for performing manual molding of the soil mass and the device of a monolithic convex up shell of the foundation in comparison with the traditional technology of the device of a solid slab foundation was revealed. But at the same time, a reduction in direct costs by 30 % was revealed in the construction of a band-shell foundation, due to a reduction in the consumption of steel and concrete, which determines the effectiveness of this type of foundation and expands its scope in the construction of buildings and structures.

Negative Mood States Are Related to the Characteristics of Facial Expression Drawing: A Cross-Sectional Study

An assessment of mood or emotion is important in developing mental health measures, and facial expressions are strongly related to mood or emotion. This study thus aimed to examine the relationship between levels of negative mood and characteristics of mouth parts when moods are drawn as facial expressions on a common platform. A cross-sectional study of Japanese college freshmen was conducted, and 1,068 valid responses were analyzed. The questionnaire survey consisted of participants’ characteristics, the Profile of Mood States (POMS), and a sheet of facial expression drawing (FACED), and the sheet was digitized and analyzed using an image-analysis software. Based on the total POMS score as an index of negative mood, the participants were divided into four groups: low (L), normal (N), high (H), and very high (VH). Lengths of drawn lines and between both mouth corners were significantly longer, and circularity and roundness were significantly higher in the L group. With increasing levels of negative mood, significant decreasing trends were observed in these lengths. Convex downward and enclosed figures were significantly predominant in the L group, while convex upward figures were significantly predominant and a tendency toward predominance of no drawn mouths or line figures was found in the H and VH groups. Our results suggest that mood states can be significantly related to the size and figure characteristics of drawn mouths of FACED on a non-verbal common platform. That is, these findings mean that subjects with low negative mood may draw a greater and rounder mouth and figures that may be enclosed and downward convex, while subjects with a high negative mood may not draw the line, or if any, may draw the line shorter and upward convex.

APPRAISAL OF SNOW IN CONTEXT OF TEMPERATURE VARIATIONS IN GILGIT BASIN

The study on Appraisal of Snow in Context of Temperature Variations in Gilgit Basin was conducted to find the snow cover change over Gilgit and Hunza Rivers. Hypsometric curve for this catchment was convex upward between normalized area and elevation. Using the MODIS snow cover product classification of snow cover was done which indicate the present of snow in the catchment. Change detection technique indicates there was high level of snow cover area change during the melting period of 2011. This area of snow which melted during melting period of 2011 was 9358.762km2. There was high level of snow cover change detection appeared in the melting period of 2011, 2012 and 2015 along the Gilgit-Hunza Rivers. The minimum snow area change was observed in 2014 during the melting period. During this year snow melting was observed with low level of change detection. Besides there was also low level of snow cover change detection observed in 2013 melting period. There was decreasing trend in snow cover change appeared in this basin.

New findings on submerged patch reefs and reefal carbonate rocks at water depths of 70–100 m on the insular shelf off Miyako-jima, southern Ryukyus, Japan

Sub-bottom profiling (SBP) surveys and bathymetric mapping conducted off the shore of Miyako-jima, which belongs to the southern Ryukyus in the Ryukyu Island Arc, have revealed the presence of mound-shaped structures 3–8 m high and 50–120 m wide at depths of 70–100 m. The SBP surveys showed that the mounds possess strong distinct, convex upward reflector shapes at the top, which we interpret as submerged reefs and reefal sediments. Additionally, modern stratified sediment layers that cover these mound-shaped structures indicate that those reefs began forming and advancing shoreward in a back-stepping fashion as a result of sea-level rise. An analysis of the mound distribution shown by SBP and multibeam echo sounding (MBES) surveys suggest that they might have been formed during the lowstand stage of sea-level change, which includes the Last Glacial Period, because the distribution of these mounds is limited to water depths of 70 to 100 m, deeper than where present-day reefs grow. The SBP images hint that such high-resolution seismic profiles, accompanied by detailed bathymetric mapping off the reefal area, have the potential to provide effective indicators of not only coral reef paleoenvironment development, but also the tectonic setting of this offshore area.

New Findings on Submerged Patch Reefs and Reefal Carbonate Rocks at Water Depths of 70-100 meters on the Insular Shelf off Miyako-jima, Southern Ryukyus, Japan

Sub-bottom profiling (SBP) surveys and bathymetric mapping conducted off the shore of Miyako-jima, which belongs to the southern Ryukyus in the Ryukyu Island Arc, have revealed the presence of mound-shaped structures 3-8 m high and 50-120 m wide at depths of 70-100 m. The SBP surveys showed that the mounds possess strong distinct, convex upward reflector shapes at the top, which we interpret as submerged reefs and reefal sediments. Additionally, modern stratified sediment layers that cover these mound-shaped structures indicate that those reefs began forming and advancing shoreward in a back-stepping fashion as a result of sea-level rise. An analysis of the mound distribution shown by SBP and multibeam echo sounding (MBES) surveys suggest that they might have been formed during the lowstand stage of sea-level change, which includes the Last Glacial Period, because the distribution of these mounds is limited to water depths of 70 m to 100 m, deeper than where present-day reefs grow. The SBP images hint that such high-resolution seismic profiles, accompanied by detailed bathymetric mapping off the reefal area, have the potential to provide effective indicators of not only coral reef paleoenvironment development, but also the tectonic setting of this offshore area.

Pyroxenite xenoliths record complex melt impregnation in the deep lithosphere of the northwestern North China Craton

Transformation of refractory cratonic mantle into more fertile lithologies is the key to the fate of cratonic lithosphere. This process has been extensively studied in the eastern North China Craton (NCC) while that of its western part is still poorly constrained. A comprehensive study of newly-found pyroxenite xenoliths from the Langshan area, in the northwestern part of this craton is integrated with a regional synthesis of pyroxenite and peridotite xenoliths to constrain the petrogenesis of the pyroxenites and provide an overview of the processes involved in the modification of the deep lithosphere. The Langshan pyroxenites are of two types, high-Mg# [Mg2+/(Mg2++Fe2+)*100 = ∼ 90, atomic ratios] olivine-bearing websterites with high equilibration temperatures (880 ∼ 970 oC), and low-Mg# (70 ∼ 80) plagioclase-bearing websterites with low equilibration temperatures (550 ∼ 835 oC). The high-Mg# pyroxenites show trade-off abundances of olivine and orthopyroxene, highly depleted bulk Sr-Nd (ƐNd = +11.41, 87Sr/86Sr = ∼0.7034) and low clinopyroxene Sr isotopic ratios (mean 87Sr/86Sr = ∼0.703). They are considered to reflect the reaction of mantle peridotites with silica-rich silicate melts derived from the convective mantle. Their depletion in fusible components (e.g., FeO, TiO2 and Na2O) and progressive exhaustion of incompatible elements suggest melt extraction after their formation. The low-Mg# pyroxenites display layered structures, convex-upward rare earth element patterns, moderately enriched bulk Sr-Nd isotopic ratios (ƐNd = -14.20 ∼ -16.74, 87Sr/86Sr = 0.7070 ∼ 0.7078) and variable clinopyroxene Sr-isotope ratios (87Sr/86Sr = 0.706-0.711). They are interpreted to be crustal cumulates from hypersthene-normative melts generated by interaction between the asthenosphere and heterogeneous lithospheric mantle. Combined with studies on regional peridotite xenoliths, it is shown that the thinning and refertilization of the lithospheric mantle was accompanied by crustal rejuvenation and that such processes occurred ubiquitously in the northwestern part of the NCC. A geodynamic model is proposed for the evolution of the deep lithosphere, which includes long-term mass transfer through a mantle wedge into the deep crust from the Paleozoic to the Cenozoic, triggered by subduction of the Paleo-Asian ocean and the Late Mesozoic lithospheric extension of eastern Asia.