scholarly journals High-Temperature Metamorphic Garnets from Grenvillian Granulites of Southwestern Oaxacan Complex (Southern Mexico): Petrology, Geochemistry, Geothermobarometry, and Tectonic Implications

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 805
Author(s):  
Laura Culí ◽  
Jesús Solé ◽  
Marc Campeny ◽  
Jeffry A. G. Oalmann
Keyword(s):  
Granulite Facies ◽  
Ultramafic Rocks ◽  
Southern Mexico ◽  
Grain Sizes ◽  
Mineral Phases ◽  
Northeastern Mexico ◽  
Almost All ◽  
Structural Levels ◽  
First Time ◽  
Rule Out

The basement of eastern Mexico comprises Grenvillian-age granulite-facies metamorphic rocks. The Oaxacan Complex represents the largest outcrop belt of this basement in Mexico. In this work, southwestern Oaxacan Complex garnets are studied from a petrographical, geochemical, and geothermobarometrical perspective for the first time. The studied garnets display different grain sizes nucleated in a polyphase evolution. The almandine end member proportion is similar in all of the studied lithotypes. The highest pyrope concentrations are found in Qz Fsp paragenesis and ultramafic rocks and the lowest pyrope concentrations are found in amphibolite. The highest grossular and spessartine concentrations are found in the amphibolite lithotype. Southwestern Oaxacan Complex garnets from paraderivate samples are more enriched in Rb, Ba, Pb, Ni, and Zn than those from orthoderivate samples enriched in Ti and V. This fact is related to the nature of the protoliths and the mineral phases that fractionate the same minor and trace elements. Garnets from para- and orthoderivate samples display 0.02–1.1 Eu/Eu* anomalies. This fact indicates that almost all of the garnets formed while the plagioclase was stable, and it does not rule out the interpretation that some garnets were peritectic. The pressure obtained using a Grt-Opx-Pl-Qz geobarometer in the southwestern Oaxacan Complex is higher than the pressure obtained in the northern part of the Complex, and it is consistent with the pressure obtained in the Grenvillian-age granulites of the Novillo Gneiss from northeastern Mexico. Geothermobarometric studies reveal different P-T features at the study site, so different structural levels of the orogen are inferred.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

scholarly journals Deciphering the effects of kosmotrope and chaotrope salts during aqueous two phase extraction (ATPE) of polyphenolic compounds and glycoalkaloids from the leaves of a nutraceutical plant, Solanum retroflexum, with the aid of UPLC-QTOF-MS

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Tebogo Mokgehle ◽  
Ntakadzeni Madala ◽  
Wilson Gitari ◽  
Nikita Tavengwa
Keyword(s):  
Polar Compounds ◽  
Ultra Performance Liquid Chromatography ◽  
Polyphenolic Compounds ◽  
Phase Extraction ◽  
Two Phase ◽  
Solanum Retroflexum ◽  
Chaotropic Salts ◽  
Almost All ◽  
First Time ◽  
Aqueous Two Phase Extraction

AbstractSolanum plants (Solanaceae) are renowned source of nutraceuticals and have widely been explored for their phytochemical constituents. This work investigated the effects of kosmotropic and chaotropic salts on the number of phytochemicals extracted from the leaves of a nutraceutical plant, Solanum retroflexum, and analyzed on the ultra-performance liquid chromatography hyphenated to a quadrupole time of flight mass spectrometer (UPLC-QTOF-MS) detector. Here, a total of 20 different compounds were putatively characterized. The majority of the identified compounds were polyphenols and glycoalkaloids. Another compound, caffeoyl malate was identified for the first time in this plant. Glycoalkaloids such as solanelagnin, solamargine, solasonine, β-solanine (I) and β-solanine (II) were found to be extracted by almost all the salts used herein. Kosmotrope salts, overall, were more efficient in extracting polar compounds with 4 more polyphenolic compounds extracted compared to the chaotropes. Chaotropes were generally more selective for the extraction of less polar compounds (glycoalkaloids) with 3 more extracted than the kosmotropes. The chaotrope and the kosmotrope that extracted the most metabolites were NaCl and Na2SO4, respectively, with 12 metabolites extracted for each salt. This work demonstrated that a comprehensive metabolome of S. retroflexum, more than what was previously reported on the same plant, can be achieved by application of kosmotropes and chaotropes as extractants with the aid of the Aqueous Two Phase Extraction approach. The best-performing salts, Na2SO4 or NaCl, could potentially be applied on a commercial scale, to meet the ever-growing demand of the studied metabolites. The Aqueous Two Phase Extraction technique was found to be efficient in simultaneous extraction of multiple metabolites which can be applied in metabolomics.

scholarly journals Comparison on the Nutrient Plunder Capacity of Orychophragmus violaceus and Brassica napus L. Based on Electrophysiological Information

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 206
Author(s):  
Cheng Zhang ◽  
Yue Su ◽  
Yanyou Wu ◽  
Haitao Li ◽  
Ying Zhou ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Orychophragmus Violaceus ◽  
Nutrient Metabolism ◽  
Brassica Napus L ◽  
Adaptive Mechanisms ◽  
Capacitive Reactance ◽  
Time Determination ◽  
Almost All ◽  
First Time

The nutrient metabolism, growth and development of plants are strongly affected by its nutrient plunder, and plants have different adaptive mechanisms to low-nutrient environments. The electrophysiological activities involve almost all life processes of plants. In this study, the active transport flow of nutrient (NAF) and nutrient plunder capacity (NPC) of plants were defined based on leaf intrinsic impedance (IZ), capacitive reactance (IXc), inductive reactance (IXL) and capacitance (IC) to evaluate the nutrient plunder capacity of plants for the first time. The results indicate that Orychophragmus violaceus had higher (p < 0.01) NPC and IC and lower (p < 0.01) IR, IXc, IXL and IZ as compared to Brassica napus L., which supports a superior ion affinity and that it could be better adapted to low-nutrient environments. UAF and NPC of plants exhibited good correlations with crude protein, crude ash and water content, and precisely revealed the plunder capacity and adaptive strategies of plants to nutrients. The present work highlights that O. violaceus had superior NPC and ion affinity compared with B. napus, and provided a novel, rapid, reliable method based on the plant’s electrophysiological information for real-time determination of the nutrient plunder capacity of plants.

scholarly journals Mineralogy and Geochemistry of Ultramafic Rocks from Rachoni Magnesite Mine, Gerakini (Chalkidiki, Northern Greece)

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 934
Author(s):  
Evangelos Tzamos ◽  
Micol Bussolesi ◽  
Giovanni Grieco ◽  
Pietro Marescotti ◽  
Laura Crispini ◽  
...  
Keyword(s):  
Raw Materials ◽  
Mining Area ◽  
Ultramafic Rocks ◽  
Northern Greece ◽  
Icp Ms ◽  
Time In Literature ◽  
History Of ◽  
First Time ◽  
The Eu

The importance of magnesite for the EU economy and industry is very high, making the understanding of their genesis for the exploration for new deposits a priority for the raw materials scientific community. In this direction, the study of the magnesite-hosting ultramafic rocks can be proved very useful. For the present study, ultramafic rock samples were collected from the magnesite ore-hosting ophiolite of the Gerakini mining area (Chalkidiki, Greece) to investigate the consecutive alteration events of the rocks which led to the metallogenesis of the significant magnesite ores of the area. All samples were subjected to a series of analytical methods for the determination of their mineralogical and geochemical characteristics: optical microscopy, XRD, SEM, EMPA, ICP–MS/OES and CIPW normalization. The results of these analyses revealed that the ultramafic rocks of the area have not only all been subjected to serpentinization, but these rocks have also undergone carbonation, silification and clay alteration. The latter events are attributed to the circulation of CO2-rich fluids responsible for the formation of the magnesite ores and locally, the further alteration of the serpentinites into listvenites. The current mineralogy of these rocks was found to be linked to one or more alteration event that took place, thus a significant contribution to the metallo- and petrogenetic history of the Gerakini ophiolite has been made. Furthermore, for the first time in literature, Fe inclusions in olivines from Greece were reported.

A garnet peridotite and a garnet-amphibole pyroxenite from South Harris, Outer Hebrides, and their bearing on the South Harris eclogite facies status

1967 ◽  
Vol 36 (279) ◽  
pp. 380-388 ◽  
Author(s):  
A. Livingstone
Keyword(s):  
Optical Properties ◽  
Granulite Facies ◽  
Garnet Peridotite ◽  
Ultramafic Rocks ◽  
Chemical Analyses ◽  
The South ◽  
Outer Hebrides ◽  
Eclogite Facies

SummaryA garnet-olivine metaperidotite and a garnet-amphibole pyroxenite are described. Chemical analyses are presented for six rocks and optical properties and chemical analyses are tabulated for clinopyroxene, almandine-pyrope garnet, and hastingsitie amphibole from the garnet-amphibole pyroxenite. A possible origin for the garnet peridotite and chemically similar granulite facies ultramafic rocks is suggested. The eclogite facies in South Harris is reinstated in the light of the data presented.

A New Sahidic Fragment of the Gospel of Luke from the Michigan Collection

2014 ◽  
Vol 56 (2) ◽  
pp. 198-204
Author(s):  
Brice C. Jones
Keyword(s):  
Gospel Of Luke ◽  
Almost All ◽  
First Time

AbstractThis article publishes for the first time the extant remains of a Sahidic Coptic manuscript containing portions of Luke 17-19. Almost all of the special Lukan pericope concerning Jesus and Zacchaeus is preserved (19:1-10), as well as most of the parable of the Dishonest Judge (18:1-8). The edition includes a transcription, translation, palaeographical analysis, critical apparatus, as well as images of the fragment.

Descriptive and illustrated diagnosis of Ophiuroidea fauna (Echinodermata) in the shallow waters of North-eastern Brazil

2015 ◽  
Vol 8 ◽  
Author(s):  
Fabilene Gomes Paim ◽  
Maria Cecília Guerrazzi ◽  
Michela Borges
Keyword(s):  
Brittle Star ◽  
Shallow Waters ◽  
Bottom Substrate ◽  
Eastern Brazil ◽  
North Eastern ◽  
Amphipholis Squamata ◽  
Biological Substrates ◽  
Almost All ◽  
First Time ◽  
Ophiocoma Echinata

In this study, we present descriptions, illustrations, comments, and bathymetric and geographic distributions of the brittle star species related to the estuary region of Camamu Bay, located in the State of Bahia, Brazil. The brittle star fauna lives on biological substrates, sand bottoms, mud and rubble in the Camamu Bay and comprises 12 species divided into five families. Almost all of them are common in the tropical and subtropical fauna of the regions of shallow water.Ophiophragmus filograneusis reported for the first time in Bahia, and nine other species are recorded for the first time in Camamu Bay:Amphipholis januarii, Amphipholis squamata, Ophiophragmus filograneus, Ophiostigma isocanthum,Ophioderma cinerea, Ophioderma januarii, Ophiactis lymani, Ophiactis savignyi andOphiocoma echinata.The results suggest that the ophiuroid assemblages are strongly affected by marine currents as well as by different kinds of bottom substrate.

scholarly journals A taxonomic revision of genus Phloeophila (Orchidaceae, Pleurothallidinae) in Ecuador

2021 ◽  
Vol 66 (1) ◽  
pp. 37-45
Author(s):  
Marco Marcelo Jiménez ◽  
Leisberth Alexis Vélez-Abarca ◽  
Luis Enrique Baquero ◽  
Carlos James Naranjo
Keyword(s):  
New Species ◽  
Morphological Characteristics ◽  
Taxonomic Revision ◽  
Identification Key ◽  
Southern Mexico ◽  
First Time ◽  
A New Species

The orchid genus Phloeophila is distributed from southern Mexico to Brazil and Bolivia, as well as Cuba. A taxonomic revision including the three Phloeophila species present in Ecuador is presented. Morphological characteristics, an identification key, maps of known localities and illustrations of the species are also included. In Ecuador, species of Phloeophila are only known from the Amazonian rainforests, growing from 890 to 1600 meters of altitude. Phloeophila condorana is described as a new species based on specimens collected in the Ecuadorian province of Zamora-Chinchipe and compared to Phloeophila nummularia. Phloeophila nummularia is reported for the first time in Peru. A lectotype for Pleurothallis echinantha is selected.

scholarly journals Exactly separable version of the Bohr Hamiltonian with the Davidson potential

2020 ◽  
Vol 16 ◽  
pp. 121
Author(s):  
D. Bonatsos ◽  
E. A. McCutchan ◽  
N. Minkov ◽  
R. F. Casten ◽  
P. Yotov ◽  
...  
Keyword(s):  
Dynamical Symmetry ◽  
Transition Rates ◽  
Stiffness Parameter ◽  
Oscillator Potential ◽  
Harmonic Oscillator Potential ◽  
Boson Model ◽  
Two Parameters ◽  
Almost All ◽  
First Time ◽  
Davidson Potential

An exactly separable version of the Bohr Hamiltonian, is obtained by using a potential of the form V (β, γ) = u(β) + u(γ)/β2, with a Davidson potential for u(β) and a stiff harmonic oscillator potential centered around γ = 0o, for u(γ).Using two parameters (β0 and the γ-stiffness parameter) the band features and B(E2) transition rates of almost all well-deformed rare-earth and actinide nuclei are reproduced, while the spectrum of the SU(3) dynamical symmetry of the Interacting Boson Model can be obtained, for the first time using the Bohr Hamiltonian.

scholarly journals U-Pb geochronology of rutile: deciphering the cooling history of the Oaxacan Complex granulites, southern Mexico

2020 ◽  
Vol 37 (2) ◽  
pp. 135-145
Author(s):  
Miguel Gerardo Adame-Martínez ◽  
Luigi Augusto Solari ◽  
Carlos Ortega-Obregón ◽  
Fanis Abdullin
Keyword(s):  
Sudden Change ◽  
Granulite Facies ◽  
High Grade ◽  
Southern Mexico ◽  
Cooling Rates ◽  
Clastic Rocks ◽  
The North ◽  
Precise Calculation ◽  
Fast Cooling ◽  
North And South

Rutile (TiO2) is a heavy mineral, commonly found as accessory in many lithologies, such as basic igneous rocks, high-grade metamorphic units, as well as a detritus in sedimentary clastic rocks. Its chemical composition is sensitive to the crystallization environment, allowing a characterization of either metabasic or metasedimentary protoliths in metamorphic rocks. Thanks to the capability to accept U in its crystalline network, at least in metasedimentary, high-grade protoliths, rutile can be dated by U-Pb geochronology. Furthermore, its closure temperature of ca. 600 °C for the U-Pb system makes rutile a suitable chronometer, complementary to zircon, to unravel provenance and exhumation paths in both sedimentary siliciclastic cover and basement units. Besides, the Zr-in thermometer allows for a very precise calculation of the rutile crystallization temperature. In the example case presented here, focused on granulite facies units of the Grenvillian Oaxacan Complex (OC), rutile crystallisation took place in the range 808–873 °C. Data for different localities indicate that cooling and exhumation after the Zapotecan granulite facies event (ca. 990 Ma) was heterogeneous among the different tectonic slices that constitute the OC. Cooling occurred in the central sector (Nochixtlán-Oaxaca) right after the granulite peak, with fast cooling rates of ca. 40 °C/Ma. To the north and south, the cooling to ca. 600 °C was much slower, with calculated cooling rates of ca. 3 °C/Ma for the northern OC outcrops in Coatepec (Puebla) to ca. 6 °C/Ma south of Ejutla (Oaxaca). This can be related to a combination of factors, such as an early collapse of some sectors of the orogen, a change of conditions in the subducing plate, or more in general, to a sudden change in the geodynamic conditions during the Zapotecan orogeny and Amazonia-Baltica amalgamation. This application example to some metasedimentary lithologies belonging to the OC demonstrates how the exhumation after the Zapotecan granulite facies event (ca. 990 Ma) was heterogeneous among the different tectonic slices that compose the OC, having occurred in the central sector (Nochixtlán-Oaxaca) right after the granulite peak, with fast cooling rates of ca. 40 ºC/M.y., whereas to the North and South the cooling to ca. 600 ºC was much slower, with calculated cooling rates of ca. 3 ºC/M.y. (north, OC outcrops in Coatepec, Puebla) to ca. 5.5 ºC/M.y. south of Ejutla (Oaxaca). This can be related to a combination of factors, such as an early collapse of some sectors of the orogen, change of conditions in the subjecting plate, or more in general, to a sudden change in the geodynamic conditions during the early stages of the Rodinia amalgamation. This example sharply illustrates the advantage of employing microanalytical techniques, able to resolve restricted crystal-domain chemical variations, to obtain accurate and precise temperature and age values. Furthermore, it is paramount to combine several mineral species with different closure temperatures, and collected in well-defined, recognized tectonic slices, to understand their behavior and construct meaningful cooling curves through geologic time, capable to better characterize and interpret their tectonic evolution.

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