The role of fractional crystallization and late-stage peralkaline melt segregation in the mineralogical evolution of Cenozoic nephelinites/phonolites from Saghro (SE Morocco)

2009 ◽  
Vol 73 (1) ◽  
pp. 59-82 ◽  
Author(s):  
J. Berger ◽  
N. Ennih ◽  
J.-C. C. Mercier ◽  
J.-P. LiéGeois ◽  
D. Demaiffe
Keyword(s):  
Fractional Crystallization ◽  
Late Stage ◽  
Nepheline Syenite ◽  
Major Element ◽  
Eudialyte Group ◽  
Intermediate Composition ◽  
Group Mineral ◽  
Melt Segregation ◽  
Evolution Trend

The Saghro Cenozoic lavas form a bimodal suite of nephelinites (with carbonatite xenoliths) and phonolites emplaced in the Anti-Atlas belt of Morocco. Despite the paucity of samples with intermediate composition between the two main types of lava (only one phonotephrite flow is reported in this area), whole-rock major element modelling shows that the two main lithologies can be linked by fractional crystallization. The most primitive modelled cumulates are calcite-bearing olivine clinopyroxenites, whereas the final stages of differentiation are characterized by the formation of nepheline-syenite cumulates. This evolution trend is classically observed in plutonic alkaline massifs associated with carbonatites. Late-stage evolution is responsible for the crystallization of hainite- and delhayelite-bearing microdomains, for the transformation of aegirine-augite into aegirine (or augite into aegirine-augite), and for the crystallization of lorenzenite and a eudialyte-group mineral as replacement products of titanite. These phases were probably formed, either by crystallization from late residual peralkaline melts, or by reaction of pre-existing minerals with such melt, or hydrothermal peralkaline fluid.

Metabentonite geochemistry: magmatic cycles and graptolite extinctions at Dob's Linn, southern Scotland

1988 ◽  
Vol 79 (1) ◽  
pp. 19-41 ◽  
Author(s):  
R. A. Batchelor ◽  
J. A. Weir
Keyword(s):  
Trace Elements ◽  
Deleterious Effect ◽  
Major Element ◽  
Magma Mixing ◽  
Volcanic Origin ◽  
Intermediate Composition ◽  
Ash Composition ◽  
Mineralogical Study ◽  
Local Extinctions ◽  
Phosphorus Levels

ABSTRACTThe Moffat Shale Group is a condensed, variable and partly pelagic sequence of mudrocks of Llandeilo—Llandovery age. The sequence has a five-fold lithological subdivision based mainly on the occurrence of grey mudstones within a succession otherwise dominated by fully euxinic black graptolitic mudrocks. Associated with the black mudrocks, especially in the Llandovery, are metabentonite beds which achieve a climax, both in thickness and in number, within the top quarter of the mudrock sequence. A geochemical and mineralogical study has confirmed a volcanic origin for the metabentonites. Major element data highlight a carbonate-dominated environment above the gregarius—convolutus Zones boundary. Phosphorus levels reach a peak at the same boundary, as well as at the Caradoc—Ashgill boundary where phosphorite horizons are known from Wales and Norway. Immobile trace elements have highlighted regular changes in source magma composition. Prolonged periods of crystal fractionation in magmas of intermediate composition gave rise, on eruption, to large volumes of silicic ash which had a deleterious effect on graptolite species and led to local extinctions. Regular fluctuations in ash composition from silicic to intermediate are ascribed to alternating fractionation and magma mixing cycles.

3-methyadenine inhibits lipopolysaccharides-induced pulmonary inflammation at the early stage of silicosis via blocking NF-κB signaling pathway

2021 ◽  
pp. 074823372110394
Author(s):  
Yujing Zhang ◽  
Shuai Huang ◽  
Shiyi Tan ◽  
Mingke Chen ◽  
Shang Yang ◽  
...  
Keyword(s):  
Lung Injury ◽  
Late Stage ◽  
Caspase 3 ◽  
Inflammatory Responses ◽  
Early Stage ◽  
Pulmonary Inflammation ◽  
Mechanism Study ◽  
Silica Dust ◽  
Tnf Α

Occupational exposure to silica dust is related to pulmonary inflammation and silicosis. Lipopolysaccharides (LPSs) could aggravate apoptosis in alveolar macrophages (AMs) of human silicosis through autophagy, yet how the reduction of autophagy attenuated LPS-induced lung injury and the related mechanisms need to be investigated. In the study, we aim to understand the role of 3-methyladenine (3-MA), an inhibitor of autophagy, in LPS-mediated inflammatory responses and fibrosis. We collected AMs from observers/silicosis patients. The results showed that LPS induced NF-κB-related pulmonary inflammation in observers and silicosis patients, as confirmed by an increase in the expression of IL-1β, IL-6, TNF-α, and p65, which could be inhibited by 3-MA treatment. In mice models, at the early stage (7d) of silicosis, but not the late (28d) stage, blocking autophagy reversed the increased levels of IL-1β, IL-6, TNF-α, and p65 caused by LPS. Mechanism study revealed that LPS triggered the expression of LC3 II, p62, and cleaved caspase-3 at the early stage exposed to silica, which could be restored by 3-MA, while there was no difference in the expression of LAMP1 either at the early or late stage of silicosis in different groups. Similarly, 3-MA treatment did not prevent fibrosis characterized by destroyed alveoli, collagen deposition, and increased expression of α-SMA and Col-1 induced by LPS at the late stage of silicosis. The results suggested that 3-MA has a role in the protection of lung injury at the early stage of silicosis and provided an experimental basis for preventive strategies of pulmonary inflammation and silicosis.

Application of the Vineyard Geologic Identity Concept to Two Marquette-producing Vineyards in the Champlain Valley, Vermont, USA

2021 ◽  
Author(s):  
Jeffrey Munroe
Keyword(s):  
Major Element ◽  
Base Cations ◽  
Nutrient Status ◽  
Exchange Capacity ◽  
Laser Scattering ◽  
Physical Foundation ◽  
Geologic Setting ◽  
Marine Embayment ◽  
Future Work

<p>The concept of “Vineyard Geological Identity” (VGI) was introduced (Ferretti, 2019: <em>Catena</em>) in recognition of the role of geologic setting in contributing to fertility, hydrology, and other important aspects of vineyard soils.  This study applied the VGI concept to two vineyards in the Champlain Valley of Vermont, USA where a burgeoning wine-making industry has been catalyzed by the development of French-American hybrid grape variety capable of surviving cold winters and bringing fruit to ripeness in relatively cool summers.  The vineyards studied here, “LP” and “SV”, both produce the hybrid grape known as “Marquette”, are at a similar elevation (~100 m), have a similar macroclimate (MAT ~7 °C, MAP ~ 850 mm, ~1400 GDD), and were inundated by proglacial Lake Vermont during deglaciation (~15,000 years ago).  Notable differences between the sites are the lithology of the underlying bedrock (Ordovician carbonate at LP, and Cambrian quartzite at SV), and the fact that the SV site was located at the edge of a marine embayment at the Pleistocene/Holocene transition after Lake Vermont drained.  The hypothesis tested was the prediction that despite their broadly similar physical settings and geologic histories, the VGI of the two vineyards would vary as a result of differences in their underlying bedrock and the soil parent materials at these settings.  Samples were collected at depths of 25, 50, 75, and 100 cm from 10 locations within the Marquette block at in each vineyard.  All samples were evaluated for grain size distribution (with the hydrometer method and a laser scattering analyzer), thermogravimetric analysis (from 25 to 1000 °C), pH, nutrient status, base saturation, and cation exchange capacity.  The deepest samples were also analyzed for mineralogy (with XRD) and major element chemistry (with XRF).  Results confirm the tested hypothesis.  Most base cations are significantly more abundant in the samples from the LP site (reflecting the underlying carbonate bedrock), and the LP site is significantly finer grained (reflecting its former deepwater location in Lake Vermont).  Conversely, at the SV vineyard Na is significantly more abundant and samples are significantly coarser, consistent with the former location of this site in the nearshore zone of a marine embayment.  In future work these results could be used as a physical foundation for evaluating the possible role of terroir in controlling aspects of the flavors expressed in Marquette wines from these two vineyards.</p>

Sergevanite, Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, a new eudialyte-group mineral from the Lovozero alkaline massif, Kola Peninsula

2020 ◽  
Vol 58 (4) ◽  
pp. 421-436 ◽  
Author(s):  
Nikita V. Chukanov ◽  
Sergey M. Aksenov ◽  
Igor V. Pekov ◽  
Dmitriy I. Belakovskiy ◽  
Svetlana A. Vozchikova ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Structural Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Eudialyte Group ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness ◽  
Alkaline Massif

ABSTRACT The new eudialyte-group mineral sergevanite, ideally Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, was discovered in highly agpaitic foyaite from the Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are microcline, albite, nepheline, arfvedsonite, aegirine, lamprophyllite, fluorapatite, steenstrupine-(Ce), ilmenite, and sphalerite. Sergevanite forms yellow to orange-yellow anhedral grains up to 1.5 mm across and the outer zones of some grains of associated eudialyte. Its luster is vitreous, and the streak is white. No cleavage is observed. The Mohs' hardness is 5. Density measured by equilibration in heavy liquids is 2.90(1) g/cm3. Calculated density is equal to 2.906 g/cm3. Sergevanite is nonpleochroic, optically uniaxial, positive, with ω = 1.604(2) and ε = 1.607(2) (λ = 589 nm). The infrared spectrum is given. The chemical composition of sergevanite is (wt.%; electron microprobe, H2O determined by HCN analysis): Na2O 13.69, K2O 1.40, CaO 7.66, La2O3 0.90, Ce2O3 1.41, Pr2O3 0.33, Nd2O3 0.64, Sm2O3 0.14, MnO 4.15, FeO 1.34, TiO2 1.19, ZrO2 10.67, HfO2 0.29, Nb2O5 1.63, SiO2 49.61, SO3 0.77, Cl 0.23, H2O 4.22, –O=Cl –0.05, total 100.22. The empirical formula (based on 25.5 Si atoms pfu, in accordance with structural data) is H14.46Na13.64K0.92Ca4.22Ce0.27La0.17Nd0.12Pr0.06Sm0.02Mn1.81Fe2+0.58Ti0.46Zr2.67Hf0.04Nb0.38Si25.5S0.30Cl0.20O81.35. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3, with a = 14.2179(1) Å, c = 30.3492(3) Å, V = 5313.11(7) Å3, and Z = 3. In the structure of sergevanite, Ca and Mn are ordered in the six-membered ring of octahedra (at the sites M11 and M12), and Na dominates over Fe2+ at the M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.12 (70) (110), 5.711 (43) (202), 4.321 (72) (205), 3.806 (39) (033), 3.551 (39) (220, 027), 3.398 (39) (313), 2.978 (95) (), 2.855 (100) (404). Sergevanite is named after the Sergevan' River, which is near the discovery locality.

scholarly journals Eudialyte Group Minerals from the Lovozero Alkaline Massif, Russia: Occurrence, Chemical Composition, and Petrogenetic Significance

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1070
Author(s):  
Julia A. Mikhailova ◽  
Yakov A. Pakhomovsky ◽  
Taras L. Panikorovskii ◽  
Ayya V. Bazai ◽  
Victor N. Yakovenchuk
Keyword(s):  
Chemical Composition ◽  
Nepheline Syenite ◽  
Granite Gneiss ◽  
Lovozero Massif ◽  
Eudialyte Group ◽  
Magmatic Stage ◽  
Late Magmatic Stage ◽  
Volcaniclastic Rocks ◽  
Layered Complex ◽  
Alkaline Massif

The Lovozero Alkaline Massif intruded through the Archean granite-gneiss and Devonian volcaniclastic rocks ca. 360 Ma ago and formed a large laccolith-type body. The lower part of the massif (the Layered complex) is composed of regularly repeating rhythms: melanocratic nepheline syenite (lujavrite, at the top), leucocratic nepheline syenite (foyaite), foidolite (urtite). The upper part of the massif (the Eudialyte complex) is indistinctly layered, and lujavrite enriched with eudialyte-group minerals (EGM) prevails there. In this article, we present the results of a study of the chemical composition and petrography of more than 400 samples of the EGM from the main types of rock of the Lovozero massif. In all types of rock, the EGM form at the late magmatic stage later than alkaline clinopyroxenes and amphiboles or simultaneously with it. When the crystallization of pyroxenes and EGM is simultaneous, the content of ferrous iron in the EGM composition increases. The Mn/Fe ratio in the EGM increases during fractional crystallization from lujavrite to foyaite and urtite. The same process leads to an increase in the modal content of EGM in the foyaite of the Layered complex and to the appearance of primary minerals of the lovozerite group in the foyaite of the Eudialyte complex.

scholarly journals KLF7: a new candidate biomarker and therapeutic target for high-grade serous ovarian cancer

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Marta De Donato ◽  
Gabriele Babini ◽  
Simona Mozzetti ◽  
Marianna Buttarelli ◽  
Alessandra Ciucci ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Overall Survival ◽  
Prognostic Marker ◽  
Late Stage ◽  
Therapeutic Target ◽  
Family Members ◽  
High Grade ◽  
Serous Ovarian Cancer

Abstract Background In spite of great progress in the surgical and clinical management, until now no significant improvement in overall survival of High-Grade Serous Ovarian Cancer (HGSOC) patients has been achieved. Important aspects for disease control remain unresolved, including unclear pathogenesis, high heterogeneity and relapse resistance after chemotherapy. Therefore, further research on molecular mechanisms involved in cancer progression are needed to find new targets for disease management. The Krüppel-like factors (KLFs) are a family of transcriptional regulators controlling several basic cellular processes, including proliferation, differentiation and migration. They have been shown to play a role in various cancer-relevant processes, in a context-dependent way. Methods To investigate a possible role of KLF family members as prognostic biomarkers, we carried out a bioinformatic meta-analysis of ovarian transcriptome datasets in different cohorts of late-stage HGSOC patients. In vitro cellular models of HGSOC were used for functional studies exploring the role of KLF7 in disease development and progression. Finally, molecular modelling and virtual screening were performed to identify putative KLF7 inhibitors. Results Bioinformatic analysis highlighted KLF7 as the most significant prognostic gene, among the 17 family members. Univariate and multivariate analyses identified KLF7 as an unfavourable prognostic marker for overall survival in late-stage TCGA-OV and GSE26712 HGSOC cohorts. Functional in vitro studies demonstrated that KLF7 can play a role as oncogene, driving tumour growth and dissemination. Mechanistic targets of KLF7 included genes involved in epithelial to mesenchymal transition, and in maintaining pluripotency and self-renewal characteristics of cancer stem cells. Finally, in silico analysis provided reliable information for drug-target interaction prediction. Conclusions Results from the present study provide the first evidence for an oncogenic role of KLF7 in HGSOC, suggesting it as a promising prognostic marker and therapeutic target.

The role of dithiophosphate as a co-collector in the flotation of a platinum group mineral ore

2012 ◽  
Vol 36-38 ◽  
pp. 100-104 ◽  
Author(s):  
K.C. Corin ◽  
J.C. Bezuidenhout ◽  
C.T. O’Connor
Keyword(s):  
Platinum Group Mineral ◽  
Group Mineral ◽  
Platinum Group

The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada

2019 ◽  
Vol 56 (7) ◽  
pp. 715-737 ◽  
Author(s):  
Yong-hua Cao ◽  
David J. Good ◽  
Robert L. Linnen ◽  
Iain M. Samson
Keyword(s):  
Major Element ◽  
Mineral Chemistry ◽  
Ultramafic Rocks ◽  
Chemical Compositions ◽  
Olivine Gabbro ◽  
Additional Observation ◽  
Midcontinent Rift ◽  
Layered Series ◽  
Incompatible Elements

The Layered Series of the Midcontinent Rift related Coldwell Complex comprises thick sections of gabbro, without any known associated ultramafic rocks. It represents a major early intrusive unit of the Coldwell Complex and consists of thick accumulations of olivine gabbro and oxide augite melatroctolite. This study combines petrography, mineral chemistry, and lithogeochemistry to constrain the magma composition and petrogenesis of the Layered Series. The presence of cumulus orthoclase together with the observation that the Layered Series rocks plot in the alkaline field on a total alkali–silica diagram indicate that the Layered Series magma has an alkaline parentage. The stratigraphy of the Layered Series cannot be fully correlated between different areas using lithogeochemistry and mineral chemistry. This together with observed normal and reverse trends for mineral chemical compositions in different areas suggest that the processes related to magma emplacement and crystallization were different in different locations. The whole-rock concentrations of incompatible elements and the compositions of major minerals of the olivine gabbro and oxide augite melatroctolite units are chemically similar. However, major element lithogeochemistry is variable, dominantly due to differences in the abundances of olivine, clinopyroxene, plagioclase, and magnetite. An additional observation is that olivine and clinopyroxene are not in chemical equilibrium. Together, these observations are interpreted to reflect a combination of multiple injections of magma and crystal sorting in an open system.

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