Geochemical and Isotopic Evolution of Late Oligocene Magmatism in Quchan, NE Iran

Magmatic activity that accompanied the collision between Arabia and Eurasia at ∼27 Ma, provides unique opportunities for understanding the triggers and magma reservoirs for collisional magmatism and its different styles in magmatic fronts and back-arcs. We present new ages and geochemical-isotopic results for magmatic rocks that formed during the collision between Arabia and Eurasia in NE Iran, which was a back-arc region to the main magmatic arcs of Iran. Our new zircon U-Pb ages indicate that collisional magmatism began at ∼24 Ma in the NE Iran back-arc, although magmatism in this area started in the Late Cretaceous time and continued until the Pleistocene. The collisional igneous rocks are characteristically bimodal, and basaltic-andesitic and dacitic-rhyolitic components show significant isotopic differences; εNd(t) = +4.4 to +7.4 and εHf(t) = +5.4 to +9.5 for mafic rocks and εNd(t) = +0.2 to +8.4 and εHf(t) = +3.4 to +12.3 for silicic rocks. The isotopic values and modeling suggest that fractional crystallization and assimilation-fractional crystallization played important roles in the genesis of felsic rocks in the NE Iran collisional zone. Trace element and isotopic modeling further emphasize that the main triggers of the magmatism in NE Iran comprise a depleted to the enriched mantle and the Cadomian continental crust of Iran. Our results also emphasize the temporal magmatic variations in the NE Iran back-arc from Late Cretaceous to Pleistocene. © 2021. The Authors

Lateral and vertical heterogeneity in the lithospheric mantle at the northern margin of the Pannonian Basin reconstructed from peridotite xenolith microstructures

International audienceThis study analyzes the microstructures and deformational characteristics of spinel peridotite xenoliths from the Nógrád‐Gömör Volcanic Field (NGVF), located on the northern margin of a young extensional basin presently affected by compression. The xenoliths show a wide range of microstructures, bearing the imprints of heterogeneous deformation and variable degrees of subsequent annealing. Olivine crystal preferred orientations (CPOs) have dominantly [010]‐fiber and orthorhombic patterns. Orthopyroxene CPOs indicate coeval deformation with olivine. Olivine J indices correlate positively with equilibration temperatures, suggesting that the CPO strength increases with depth. In contrast, the intensity of intragranular deformation in olivine varies as a function of the sampling locality. We interpret the microstructures and CPO patterns as recording deformation by dislocation creep in a transpressional regime, which is consistent with recent tectonic evolution in the Carpathian‐Pannonian region due to the convergence between the Adria microplate and the European platform. Postkinematic annealing is probably linked to percolation of metasomatism by mafic melts through the upper mantle of the NGVF prior to the eruption of the host alkali basalt. Elevated equilibration temperatures in xenoliths from the central part of the volcanic field are interpreted to be associated with the last metasomatic event, which only shortly preceded the ascent of the host magma. Despite well‐developed olivine CPOs in the xenoliths, which imply a strong seismic anisotropy, the lithospheric mantle alone cannot account for the shear wave splitting delay times measured in the NGVF, indicating that deformation in both the lithosphere and the asthenosphere contributes to the observed shear wave splitting

Estimated Costs and Returns for Catfish Farms with Recirculating Ponds Along the Upper Texas Coast.

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Dellagiustaite: A Novel Natural Spinel Containing V2+

Dellagiustaite, ideally Al2V2+O4, is a new spinel-group mineral from Sierra de Comechingones, San Luis, Argentina, where it is found associated with hibonite (containing tubular inclusions, 5\u2013100 \ub5m, of metallic vanadium), grossite, and two other unknown phases with ideal stoichiometry of Ca2Al3O6F and Ca2Al2SiO7. A very similar rock containing dellagiustaite has been found at Mt Carmel (northern Israel), where super-reduced mineral assemblages have crystallized from high-T melts trapped in corundum aggregates (micro-xenoliths) within picritic-tholeiitic lavas ejected from Cretaceous volcanoes. In the holotype, euhedral grains of dellagiustaite are found as inclusions in grossite. The empirical average chemical formula of dellagiustaite is (Al1.09 V2+ 0.91 V3+ 0.87 Mg0.08 Ti3+ 0.04 Mn0.01)\u3a33O4, but it may show limited replacement of V2+ by Mg and of V3+ by Al. As Al is the dominant trivalent cation, the ideal formula is Al2V2+O4 according to the current IMA rules. Dellagiustaite shows the usual space group of spinel-group minerals (Fd3m, R1 = 1.46%) with a = 8.1950(1) \uc5. The observed mean bond lengths = 1.782(2) \uc5 and = 2.0445(9) \uc5, the observed site scattering (T = 13.3 eps, M = 22.5 eps), and the chemical composition show that dellagiustaite is an inverse spinel: T tetrahedra are occupied by Al3+, whereas M octahedra are occupied by V2+ and V3+, leading to the site assignment asTAlM(V2+ 0.91 V3+ 0.88 Al3+ 0.09 Mg0.08 Ti3+ 0.03 Mn0.01)O4. \ua9 2018 by the authors. Licensee MDPI, Basel, Switzerland

Adult attachment style across individuals and role-relationships: Avoidance is relationship-specific, but anxiety shows greater generalizability

A generalisability study examined the hypotheses that avoidant attachment, reflecting the representation of others, should be more relationship-specific (vary across relationships more than across individuals), while attachment anxiety, reflecting self-representation, should be more generalisable across a person’s relationships. College students responded to 6-item questionnaire measures of these variables for 5 relationships (mother, father, best same-gender friend, romantic partner or best opposite-gender friend, other close person), on 3 (N = 120) or 2 (N = 77) occasions separated by a few weeks. Results supported the hypotheses, with the person variance component being larger than the relationship-specific component for anxiety, and the opposite happening for avoidance. Anxiety therefore seems not to be as relationship-specific as previous research suggested. Possible reasons for discrepancies between the current and previous studies are discussed

Subduction initiation and back-arc opening north of Neo-Tethys: Evidence from the Late Cretaceous Torbat-e-Heydarieh ophiolite of NE Iran

How new subduction zones form is an ongoing scientific question with key implications for our understanding of how this process influences the behavior of the overriding plate. Here we focus on the effects of a Late Cretaceous subduction-initiation (SI) event in Iran and show how SI caused enough extension to open a back-arc basin in NE Iran. The Late Cretaceous Torbat-e-Heydarieh ophiolite (THO) is well exposed as part of the Sabzevar-Torbat-e-Heydarieh ophiolite belt. It is dominated by mantle peridotite, with a thin crustal sequence. The THO mantle sequence consists of harzburgite, clinopyroxene-harzburgite, plagioclase lherzolite, impregnated lherzolite, and dunite. Spinel in THO mantle peridotites show variable Cr# (10−63), similar to both abyssal and fore-arc peridotites. The igneous rocks (gabbros and dikes intruding mantle peridotite, pillowed and massive lavas, amphibole gabbros, plagiogranites and associated diorites, and diabase dikes) display rare earth element patterns similar to MORB, arc tholeiite and back-arc basin basalt. Zircons from six samples, including plagiogranites and dikes within mantle peridotite, yield U-Pb ages of ca. 99−92 Ma, indicating that the THO formed during the Late Cretaceous and was magmatically active for ∼7 m.y. THO igneous rocks have variable εNd(t) of +5.7 to +8.2 and εHf(t) ranging from +14.9 to +21.5; zircons have εHf(t) of +8.1 to +18.5. These isotopic compositions indicate that the THO rocks were derived from an isotopically depleted mantle source similar to that of the Indian Ocean, which was slightly affected by the recycling of subducted sediments. We conclude that the THO and other Sabzevar-Torbat-e-Heydarieh ophiolites formed in a back-arc basin well to the north of the Late Cretaceous fore-arc, now represented by the Zagros ophiolites, testifying that a broad region of Iran was affected by upper-plate extension accompanying Late Cretaceous subduction initiation

Diagnostic criteria and symptom grading for delayed gastric conduit emptying after esophagectomy for cancer: international expert consensus based on a modified Delphi process

Delayed gastric conduit emptying (DGCE) after esophagectomy for cancer is associated with adverse outcomes and troubling symptoms. Widely accepted diagnostic criteria and a symptom grading tool for DGCE are missing. This hampers the interpretation and comparison of studies. A modified Delphi process, using repeated web-based questionnaires, combined with live interim group discussions was conducted by 33 experts within the field, from Europe, North America, and Asia. DGCE was divided into early DGCE if present within 14 days of surgery and late if present later than 14 days after surgery. The final criteria for early DGCE, accepted by 25 of 27 (93%) experts, were as follows: >500 mL diurnal nasogastric tube output measured on the morning of postoperative day 5 or later or >100% increased gastric tube width on frontal chest x-ray projection together with the presence of an air-fluid level. The final criteria for late DGCE accepted by 89% of the experts were as follows: the patient should have 'quite a bit' or 'very much' of at least two of the following symptoms; early satiety/fullness, vomiting, nausea, regurgitation or inability to meet caloric need by oral intake and delayed contrast passage on upper gastrointestinal water-soluble contrast radiogram or on timed barium swallow. A symptom grading tool for late DGCE was constructed grading each symptom as: 'not at all', 'a little', 'quite a bit', or 'very much', generating 0, 1, 2, or 3 points, respectively. For the five symptoms retained in the diagnostic criteria for late DGCE, the minimum score would be 0, and the maximum score would be 15. The final symptom grading tool for late DGCE was accepted by 27 of 31 (87%) experts. For the first time, diagnostic criteria for early and late DGCE and a symptom grading tool for late DGCE are available, based on an international expert consensus process

Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe