Thin crust and exposed mantle control sulfide differentiation in slow-spreading ridge magmas

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Geology 45 (2017): 935-938, doi:10.1130/G39287.1.Gabbroic veins enclosed in mantle peridotite from ocean core complexes next to oceanic transform faults demonstrate sub-crustal crystallization of silicate minerals from a MORB-like melt. Cooler lithosphere there may also affect sulfide crystallization and the metal budget of the lower and upper crust but the related sulfide behavior is poorly understood. Here, we use chalcophile elements to trace sulfide crystallization in a suite of MORB's erupted at the Kane Megamullion south of the Kane Fracture Zone along the Mid-Atlantic Ridge. Cool lithosphere there is inferred from a low magma supply, and lithostratigraphic evidence for thin crust with abundant mantle rock exposed to the seafloor (Dick et al., 2008). We show that the concentrations of Cu, Zn, As, Ga, Pb, Sb and Tl in the Kane Megamullion MORB's rise linearly with melt differentiation expressed by decreasing MgO and Ni content. The low-pressure fractional crystallization within the crust thus occurs at sulfur-undersaturated conditions. Sulfur-undersaturated MORB's are unusual. At the Kane Megamullion, however, the thin crust allows melt to more extensively interact with the shallow and serpentinized mantle. We argue that sulfur and chalcophile elements have been lost from the melt due to sulfide crystallization during melt-rock reaction in the shallow mantle.This research was funded by a Diamond Grant of the Polish Ministry of Science and Higher Education (DI2012 2057 42 to Ciazela), and partially supported by the European Association of Geochemistry (Early Career Science Ambassador grant to Ciazela) and the National Science Foundation (grant #’s OCE1434452 and OCE1637130 to Dick)

Sulfide enrichment at an oceanic crust-mantle transition zone : Kane Megamullion (23°N, MAR)

Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 230 (2018): 155-189, doi:10.1016/j.gca.2018.03.027.The Kane Megamullion oceanic core complex located along the Mid-Atlantic Ridge (23°30′N, 45°20′W) exposes lower crust and upper mantle directly on the ocean floor. We studied chalcophile elements and sulfides in the ultramafic and mafic rocks of the crust-mantle transition and the mantle underneath. We determined mineralogical and elemental composition and the Cu isotope composition of the respective sulfides along with the mineralogical and elemental composition of the respective serpentines. The rocks of the crust-mantle transition zone (i.e., plagioclase harzburgite, peridotite-gabbro contacts, and dunite) overlaid by troctolites are by one order of magnitude enriched in several chalcophile elements with respect to the spinel harzburgites of the mantle beneath. Whereas the range of Cu concentrations in spinel harzburgites is 7–69 ppm, the Cu concentrations are highly elevated in plagioclase harzburgites with a range of 90–209 ppm. The zones of the peridotite-gabbro contacts are even more enriched, exhibiting up to 305 ppm Cu and highly elevated concentrations of As, Zn, Ga, Sb and Tl. High Cu concentrations show pronounced correlation with bulk S concentrations at the crust-mantle transition zone implying an enrichment process in this horizon of the oceanic lithosphere. We interpret this enrichment as related to melt-mantle reaction, which is extensive in crust-mantle transition zones. In spite of the ubiquitous serpentinization of primary rocks, we found magmatic chalcopyrites [CuFeS2] as inclusions in plagioclase as well as associated with pentlandite [(Fe,Ni)9S8] and pyrrhotite [Fe1−xS] in polysulfide grains. These chalcopyrites show a primary magmatic δ65Cu signature ranging from −0.04 to +0.29 ‰. Other chalcopyrites have been dissolved during serpentinization. Due to the low temperature (<300 °C) of circulating fluids chalcophile metals from primary sulfides have not been mobilized and transported away but have been trapped in smaller secondary sulfides and hydroxides. Combined with the Cu deposits documented in the crust-mantle transition zones of various ophiolite complexes, our results indicate that the metal enrichment, increased sulfide modes, and potentially formation of small sulfide deposits could be expected globally along the petrological Moho.This research was funded by a Diamond Grant of the Polish Ministry of Science and Higher Education (DI2012 2057 42 to J. Ciazela), and partly supported by grants of the U.S. National Science Foundation (OCE1434452 and OCE1637130 to H.J.B. Dick), and the German Science Foundation (Bo2941/4-1 to R. Botcharnikov)

Sulfide enrichment along igneous layer boundaries in the lower oceanic crust: IODP Hole U1473A, Atlantis Bank, Southwest Indian Ridge

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pieterek, B., Ciazela, J., Boulanger, M., Lazarov, M., Wegorzewski, A., Pańczyk, M., Strauss, H., Dick, H. J. B., Muszyński, A., Koepke, J., Kuhn, T., Czupyt, Z., & France, L. Sulfide enrichment along igneous layer boundaries in the lower oceanic crust: IODP Hole U1473A, Atlantis Bank, Southwest Indian Ridge. Geochimica et Cosmochimica Acta, 320, (2022): 179–206, https://doi.org/10.1016/j.gca.2022.01.004.Reactive porous or focused melt flows are common in crystal mushes of mid-ocean ridge magma reservoirs. Although they exert significant control on mid-ocean ridge magmatic differentiation, their role in metal transport between the mantle and the ocean floor remains poorly constrained. Here we aim to improve such knowledge for oceanic crust formed at slow-spreading centers (approximately half of present-day oceanic crust), by focusing on specific igneous features where sulfides are concentrated. International Ocean Discovery Program (IODP) Expedition 360 drilled Hole U1473A 789 m into the lower crust of the Atlantis Bank oceanic core complex, located at the Southwest Indian Ridge. Coarse-grained (5–30 mm) olivine gabbro prevailed throughout the hole, ranging locally from fine- (30 mm). We studied three distinct intervals of igneous grain size layering at 109.5–110.8, 158.0–158.3, and 593.0–594.4 meters below seafloor to understand the distribution of sulfides. We found that the layer boundaries between the fine- and coarse-grained gabbro were enriched in sulfides and chalcophile elements. On average, sulfide grains throughout the layering were composed of pyrrhotite (81 vol.%; Fe1-xS), chalcopyrite (16 vol.%; CuFeS2), and pentlandite (3 vol.%; [Ni,Fe,Co]9S8), which reflect paragenesis of magmatic origin. The sulfides were most commonly associated with Fe-Ti oxides (titanomagnetites and ilmenites), amphiboles, and apatites located at the interstitial positions between clinopyroxene, plagioclase, and olivine. Pentlandite exsolution textures in pyrrhotite indicate that the sulfides formed from high-temperature sulfide liquid separated from mafic magma that exsolved upon cooling. The relatively homogenous phase proportion within sulfides along with their chemical and isotopic compositions throughout the studied intervals further support the magmatic origin of sulfide enrichment at the layer boundaries. The studied magmatic layers were likely formed as a result of intrusion of more primitive magma (fine-grained gabbro) into the former crystal mush (coarse-grained gabbro). Sulfides from the coarse-grained gabbros are Ir-Platinum Group Element-rich (PGE; i.e., Ir, Os, Ru) but those from the fine-grained gabbros are Pd-PGE-rich (i.e., Pd, Pt, Rh). Notably, the sulfides from the layer boundaries are also enriched in Pd-PGEs, and therefore elevated sulfide contents at the boundaries were likely related to the new intruding melt. Because S concentration at sulfide saturation level is dependent on the Fe content of the melt, sulfide crystallization may have been caused by FeO loss, both via crystallization of late-precipitating oxides at the boundaries, and by exchange of Fe and Mg between melt and Fe-bearing silicates (olivine and clinopyroxene). The increased precipitation of sulfide grains at the layer boundaries might be widespread in the lower oceanic crust, as also observed in the Semail ophiolite and along the Mid-Atlantic Ridge. Therefore, this process might affect the metal budget of the global lower oceanic crust. We estimate that up to ∼20% of the Cu, ∼8% of the S, and ∼84% of the Pb of the oceanic crust inventory is accumulated at the layer boundaries only from the interaction between crystal mush and new magma.This research was funded by National Science Centre Poland (PRELUDIUM 12 no. 2016/23/N/ST10/00288), Graduate Academy of the Leibniz Universität Hannover (60421784), and ECORD Research Grant to J. Ciazela, as well as Deutsche Forschungsgemeinschaft (KO1723/23-1) to J. Koepke and H. Strauss. J. Ciazela is additionally supported within the START program of the Foundation for Polish Science (FNP). This is CRPG contribution No. 2813

Оцінка морфофункціонального стану організму щурів за вивчення токсичності препарату на основі тилмікозину

The article presents the study results of the acute and subacute toxicity of the veterinary drug “Tylmozyn 25” (solution for oral administration) based on tilmicosin. Intra-gastric administration of “Tylmozyn 25” to white mice at a dose of 25000 mg/kg of body weight caused the death of 100% of the animals, a dose of 15000 mg/kg of body weight caused the death of 66% of the white mice. The average time of death was 2 and 5 hours correspondingly. While determining the toxicity of “Tylmozyn 25” in white rats, we did not spot the death of any studied animal at any administered dose (5000, 15000, 25000 mg/kg of body weight). Based on the result of our study, we conclude that the veterinary drug Tylmozyn 25 belongs to the fourth of toxicity class – low toxic substances. LD50 of Tylmozyn 25 in white mice is 14167 mg/kg, while in white rats LD50 is higher than 25000 mg/kg. Testing on white rats intra-gastric drug “Tylmozyn 25” during for 14 days, both in therapeutic (80 mg/kg of body weight) and 10-fold doses (800 mg/kg of body weight) did not cause animal death, but caused a decrease in body weight, a significant decrease in the coefficients of weight of the liver and spleen and a tendency to increase the coefficients of weight of the heart and lungs compared with the animals of the control group. Animals which got the drug at a dose of 800 mg/kg of body weight showed erythrocytosis, leukopenia, increased enzymatic activity of AST, ALT, and LDH, the content of total protein against to decrease urea and creatinine, which may indicate impaired liver, kidney function and hematopoietic organs. The macroscopic and microscopic structure of the internal organs of the experimental rats is preserved. Rats receiving a tenfold therapeutic dose of the drug for 14 days, histologically revealed the most granular protein dystrophy in the liver and kidneys, which was manifested by discomplexation of the lamellae, presence of hepatocytes with uneven granular cytoplasm, slightly colored cytoplasm, hypertrophied nuclei, renal convoluted tubules and narrowing of their lumen, compaction of the mesh of the renal corpuscle. In the myocardium, the branching, swelling of the muscle fibers, swelling of the stroma with cell infiltrates, mainly of the lympho-histiocytic series, was observed, which indicated the development of serosa myocarditis. Structural changes in the liver, kidneys and heart were confirmed by biochemical parameters of the enzymatic activity of the serum of rats of this group.У статті наведені результати вивчення гострої та підгострої токсичності препарату “Тилмозин 25” (розчин для перорального застосування), виготовленого на основі тилмікозину. Внутрішньошлункове введення препарату “Тилмозин 25” білим мишам, у дозі 25000 мг/кг маси тіла викликало 100% загибель тварин, доза 15000 мг/кг – 66% загибелі тварин. Середній час загибелі становив 2 та 5 годин відповідно. При визначенні гострої токсичності препарату “Тилмозин 25” на білих щурах загибелі тварин не виявляли за введення жодної з доз (5000, 15000, 25000 мг/кг маси тіла). У результаті проведених досліджень було встановлено, що препарат “Тилмозин 25” належить до 4-го класу токсичності – малотоксичні речовини. ЛД50 при його внутрішньошлунковому введенні білим мишам становить 14167 мг/кг, а для білих щурів є більшою за 25000&nbsp;мг/кг. Застосування білим щурам внутрішньошлунково препарату “Тилмозин 25” впродовж 14 діб як у терапевтичній (80 мг/кг маси тіла), так і 10-кратній дозах (800 мг/кг маси тіла) не викликало загибелі тварин, проте спричиняло зменшення маси тіла, достовірне зниження коефіцієнтів маси печінки та селезінки і тенденцію до збільшення коефіцієнтів маси серця і легень порівняно з тваринами контрольної групи. У тварин, які отримували досліджуваний препарат в дозі 800 мг/кг маси тіла, встановлено еритроцитоз, лейкопенію, підвищення активності АлАТ, АсАТ, ЛДГ, вмісту загального білка на фоні зниження вмісту сечовини та креатиніну, що може вказувати на порушення функції печінки, нирок та органів кровотворення. Макроскопічна та мікроскопічна структура внутрішніх органів досліджуваних груп щурів збережена. У щурів, які отримували 10-кратну терапевтичну дозу препарату впродовж 14 діб, гістологічно виявляли вогнища зернистої білкової дистрофії в печінці та нирках, що проявлялося дискомплексацією пластинчатої будови печінкових часточок, наявність гепатоцитів з неоднорідною, зернистою, слабо забарвленою цитоплазмою та гіпертрофованими ядрами, набуханням епітелію звивистих ниркових канальців та звуженням їхнього просвіту, ущільненням сітки ниркових клубочків. У міокарді спостерігали розволокнення, набухання м’язових волокон, набряк строми з клітинними інфільтратами переважно лімфо-гістіоцитарного ряду, що вказувало на розвиток серозного міокардиту. Встановлені структурні зміни у печінці, нирках, серці були підтверджені біохімічними показниками ферментативної активності сироватки крові щурів даної групи

Identification and characterization of the maize arogenate dehydrogenase gene family

In plants, the amino acids tyrosine and phenylalanine are synthesized from arogenate by arogenate dehydrogenase and arogenate dehydratase, respectively, with the relative flux to each being tightly controlled. Here the characterization of a maize opaque endosperm mutant (mto140), which also shows retarded vegetative growth, is described The opaque phenotype co-segregates with a Mutator transposon insertion in an arogenate dehydrogenase gene (zmAroDH-1) and this led to the characterization of the four-member family of maize arogenate dehydrogenase genes (zmAroDH-1–zmAroDH-4) which share highly similar sequences. A Mutator insertion at an equivalent position in AroDH-3, the most closely related family member to AroDH-1, is also associated with opaque endosperm and stunted vegetative growth phenotypes. Overlapping but differential expression patterns as well as subtle mutant effects on the accumulation of tyrosine and phenylalanine in endosperm, embryo, and leaf tissues suggest that the functional redundancy of this gene family provides metabolic plasticity for the synthesis of these important amino acids. mto140/arodh-1 seeds shows a general reduction in zein storage protein accumulation and an elevated lysine phenotype typical of other opaque endosperm mutants, but it is distinct because it does not result from quantitative or qualitative defects in the accumulation of specific zeins but rather from a disruption in amino acid biosynthesis

Biocompatibility of Graphene Oxide

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 μg/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 μg/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered

Atmospheric River Tracking Method Intercomparison Project (ARTMIP): project goals and experimental design

The Atmospheric River Tracking Method Intercomparison Project (ARTMIP) is an international collaborative effort to understand and quantify the uncertainties in atmospheric river (AR) science based on detection algorithm alone. Currently, there are many AR identification and tracking algorithms in the literature with a wide range of techniques and conclusions. ARTMIP strives to provide the community with information on different methodologies and provide guidance on the most appropriate algorithm for a given science question or region of interest. All ARTMIP participants will implement their detection algorithms on a specified common dataset for a defined period of time. The project is divided into two phases: Tier 1 will utilize the Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) reanalysis from January 1980 to June 2017 and will be used as a baseline for all subsequent comparisons. Participation in Tier 1 is required. Tier 2 will be optional and include sensitivity studies designed around specific science questions, such as reanalysis uncertainty and climate change. High-resolution reanalysis and/or model output will be used wherever possible. Proposed metrics include AR frequency, duration, intensity, and precipitation attributable to ARs. Here, we present the ARTMIP experimental design, timeline, project requirements, and a brief description of the variety of methodologies in the current literature. We also present results from our 1-month proof-of-concept trial run designed to illustrate the utility and feasibility of the ARTMIP project

Distinct Genetic Architectures for Male and Female Inflorescence Traits of Maize

We compared the genetic architecture of thirteen maize morphological traits in a large population of recombinant inbred lines. Four traits from the male inflorescence (tassel) and three traits from the female inflorescence (ear) were measured and studied using linkage and genome-wide association analyses and compared to three flowering and three leaf traits previously studied in the same population. Inflorescence loci have larger effects than flowering and leaf loci, and ear effects are larger than tassel effects. Ear trait models also have lower predictive ability than tassel, flowering, or leaf trait models. Pleiotropic loci were identified that control elongation of ear and tassel, consistent with their common developmental origin. For these pleiotropic loci, the ear effects are larger than tassel effects even though the same causal polymorphisms are likely involved. This implies that the observed differences in genetic architecture are not due to distinct features of the underlying polymorphisms. Our results support the hypothesis that genetic architecture is a function of trait stability over evolutionary time, since the traits that changed most during the relatively recent domestication of maize have the largest effects