Late Precambrian ash-flow tuffs and associated rocks of the Harbour Main Group near Colliers, eastern Newfoundland: chemistry and magmatic affinities

1979 ◽  
Vol 16 (1) ◽  
pp. 167-181 ◽  
Author(s):  
G. T. Nixon ◽  
V. S. Papezik
Keyword(s):  
Bulk Composition ◽  
Main Group ◽  
Small Bodies ◽  
Clastic Sediments ◽  
Tectonic Environment ◽  
Extensional Tectonic ◽  
Intrusive Rocks ◽  
Volcanic Pile ◽  
High Level ◽  
Bulk Chemistry

The Colliers Peninsula, a typical area in the western part of the Harbour Main Group in eastern Newfoundland, is underlain by three steeply-dipping sequences of ash-flow tuffs 250–500 m thick, separated by clastic sediments, conformably overlain by subaerial mafic flows and cut by small bodies of high-level intrusive rocks rich in plagioclase phenocrysts. All rocks are of low metamorphic grade.The two lower pyroclastic sequences have a bulk composition of rhyolite and alkali rhyolite; they contain phenocrysts of albite, quartz, and biotite. Na/K ratios are highly variable; the albite crystals may be pseudomorphous after anorthociase. The upper sequence, rhyodacitic in bulk composition, has lower Si and higher Na; it lacks quartz and biotite phenocrysts but contains small amounts of calcic augite and altered olivine. The mafic flows (50% SiO2) show high Al and alkalies and low Ca and Ti. The porphyritic intrusives have 60–65% SiO2, but their bulk chemistry is otherwise similar to that of the ash-flow tuffs.The present composition of the rocks reflects complex chemical adjustments, both contemporaneous with and subsequent to the magmatic event. However, mineralogical and chemical data and trends considered to be a part of the original magmatic heritage are consistent with suggestions that the western (probably lower) part of the Harbour Main volcanic pile was formed in a continental, extensional tectonic environment.

Features of psychoemotional condition and stress-assosiatate hormons bioproduction in pregnant women after application of assisted reproductive technologies

2018 ◽  
pp. 118-121
Author(s):  
L.M. Vygivska ◽  
◽  
I.A. Usevych ◽  
I.V. Maidannyk ◽  
V.F. Oleshko ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Emotional State ◽  
Assisted Reproductive Technologies ◽  
Past History ◽  
Reproductive Technologies ◽  
Main Group ◽  
Psychological Status ◽  
Perinatal Complications ◽  
History Of ◽  
High Level

The article represents the results of a prospective clinical and paraclinical examination of women with a history of infertility, pregnancy in which occurred as a result of the assisted reproductive technologies application. The objective: was to study the dynamics of pregnancy features of the psycho - emotional state and the concentration of stress-associated hormones in the serum of pregnant women after the application of assisted reproductive technologies in order to improve the tactics of antenatal care and prevention of obstetric and perinatal complications. Materials and methods. The main group consisted of 80 pregnant women with endocrine infertility, in which pregnancy occurred as a result of therapeutic cycles of ART, control – 50 first-pregnant women with spontaneous fertilization, taken in an arbitrary order of clinical, statistical and laboratory and instrumental studies. In pregnant women of the study groups, in order to determine the psycho emotional state in the screening mode, a clinical interview was conducted by filling out questionnaires that contained the Spilberger test questions in modification of Y.L. Hanina and «Test of relationof pregnant» by the method of I.V. Dobryakova. In the dynamics of pregnancy, the concentration of prolactin (PRL) and cortisol (K) was determined by the enzyme immunoassay on the Reader-MSR-1000 apparatus using test systems manufactured by Hema-Medicament (Russia). Results. Pregnant women with infertility in past history were characterized by a state of chronic stress. According to the results of the Spielberger test in modification Y .L. Hanina every second pregnant of main group had a high level of reactive and every fourth personal anxiety. Almost 90.0% of pregnant women after art are characterized by the presence of pathological PKGD, among which an alarming and depressive type was registered in every sixth and twelfth pregnant woman, respectively. The obtained data are confirmed by the results of the study of the level of K and PRL. For women with a history of infertility and pregnancy, which is the result of therapeutic cycles of ART, inherent in increasing concentrations of stress-associated hormones – cortisol and prolactin, which is one of the reasons for the complicated course of pregnancy and requires reasonable pathogenetic correction. Conclusion. For women who are pregnant as a result of the use of therapeutic cycles of art characterized by a high level of personal and reactive anxiety and PKGD, which confirm the presence of neuropsychiatric and afferent disorders. Increasing the concentration of stress-associated hormones is one of the causes of complicated pregnancy and requires a reasonable pathogenetic correction. Key words: pregnancy, infertility, assisted reproductive technologies, psychological status, cortisol, prolactin.

The Ferguson Lake deposit: an example of Ni–Cu–Co–PGE mineralization emplaced in a back-arc basin setting?

2018 ◽  
Vol 55 (8) ◽  
pp. 958-979 ◽  
Author(s):  
P. Acosta-Góngora ◽  
S.J. Pehrsson ◽  
H. Sandeman ◽  
E. Martel ◽  
T. Peterson
Keyword(s):  
Mineral Exploration ◽  
Ultramafic Rocks ◽  
Geodynamic Setting ◽  
Ocean Ridges ◽  
Tectonic Environment ◽  
Pge Mineralization ◽  
Extensional Tectonic ◽  
Basaltic Composition ◽  
Greenstone Belts ◽  
Back Arc

The world’s largest Ni–Cu–Platinum group element (PGE) deposits are dominantly hosted by ultramafic rocks within continental extensional settings (e.g., Raglan, Voisey’s Bay), resulting in a focus on exploration in similar geodynamic settings. Consequently, the economic potential of other extensional tectonic environments, such as ocean ridges and back-arc basins, may be underestimated. In the northeastern portion of the ca. 2.7 Ga Yathkyed greenstone belt of the Chesterfield block (western Churchill Province, Canada), the Ni–Cu–Co–PGE Ferguson Lake deposit is hosted by >2.6 Ga hornblenditic to gabbroic rocks of the Ferguson Lake Igneous Complex (FLIC), which is metamorphosed up to amphibolitic facies. The FLIC has a basaltic composition (Mg# = 31–72), flat to slightly negatively sloped normalized trace element patterns (La/YbPM = 0.7–3.5), and negative Zr, Ti, and Nb anomalies. The FLIC rocks are geochemically similar to the 2.7 Ga back-arc basin tholeiitic basalts from the adjacent Yathkyed and MacQuoid greenstone belts (Mg# = 30–67; La/YbPM = 0.3–3.0), but the Ferguson Lake intrusions appear to be more crustally contaminated. We interpret the FLIC to have formed in an equivalent back-arc basin setting. This geodynamic setting is rare for the formation of Ni–Cu–PGE occurrences, and only few examples of this tectonic environment (or variations of it, e.g., rifted back-arc) are found in other Proterozoic and Archean sequences (e.g., Lorraine deposit, Quebec). We suggest that back-arc basin-derived mafic rocks within the Yathkyed and other Neoarchean greenstone belts of the Chesterfield block (MacQuoid and Angikuni) could represent important targets for future mineral exploration.

Geochemistry, zircon ages and whole-rock Nd isotopic systematics for Palaeoproterozoic A-type granitoids in the northern part of the Delhi belt, Rajasthan, NW India: implications for late Palaeoproterozoic crustal evolution of the Aravalli craton

2006 ◽  
Vol 144 (2) ◽  
pp. 361-378 ◽  
Author(s):  
PARAMPREET KAUR ◽  
NAVEEN CHAUDHRI ◽  
INGRID RACZEK ◽  
ALFRED KRÖNER ◽  
ALBRECHT W. HOFMANN
Keyword(s):  
Source Region ◽  
Magma Source ◽  
Crustal Evolution ◽  
Nd Isotope ◽  
Tectonic Environment ◽  
Granulite Metamorphism ◽  
Extensional Tectonic ◽  
Aravalli Craton ◽  
Isotope Systematics

Determination of zircon ages as well as geochemical and Sm–Nd isotope systematics of granitoids in the Khetri Copper Belt of the Aravalli mountains, NW India, constrain the late Palaeoproterozoic crustal evolution of the Aravalli craton. The plutons are typical A-type within-plate granites, derived from melts generated in an extensional tectonic environment. They display REE and multi-element patterns characterized by steep LREE-enriched and almost flat HREE profiles and distinct negative anomalies for Sr, P and Ti. Initial εNd values range from −1.3 to −6.2 and correspond to crustal sources with mean crustal residence ages of 2.5 to 2.1 Ga. A lower mafic crustal anatectic origin is envisaged for these granitoids, and the heterogeneous εNd(t) values are inferred to have been acquired from the magma source region. Zircon Pb–Pb evaporation and U–Pb ages indicate widespread rift-related A-type magmatism at 1711–1660 Ma in the northern Delhi belt and also suggest a discrete older magmatic event at around 1800 Ma. The emplacement ages of the compositionally distinct A-type granitoid plutons, and virtually coeval granulite metamorphism and exhumation in another segment of the Aravalli mountains, further signify that part of the Aravalli crust evolved during a widespread extensional event in late Palaeoproterozoic time.

A Grenville-age layered intrusion in the subsurface of west Texas: petrology, petrography, and possible tectonic setting

1995 ◽  
Vol 32 (12) ◽  
pp. 2159-2166 ◽  
Author(s):  
Hulusi Kargi ◽  
Calvin G. Barnes
Keyword(s):  
Tectonic Setting ◽  
Basaltic Magma ◽  
Layered Intrusion ◽  
Mafic Magma ◽  
Magma Source ◽  
Rock Types ◽  
Hornblende Gabbro ◽  
Tectonic Environment ◽  
Extensional Tectonic ◽  
General Order

The Nellie intrusion is a thick (more than 4420 m) mafic to ultramafic layered intrusion with a radiometric age of ~1163 Ma. Rock types change abruptly with stratigraphic height and include norite, pyroxenite, gabbronorite, hornblende gabbro, gabbro, anorthosite, harzburgite, and lherzolite. Norite is most abundant, but gabbro and hornblende gabbro are locally abundant. Rare olivine-rich layers are also present. The general order of crystallization was olivine, orthopyroxene, plagioclase + clinopyroxene, and hornblende. Mg#'s, expressed as 100 Mg/(Mg + Fe), range from 76.3 to 85.8 for olivine, 56.7 to 84.9 for orthopyroxene, 62.5 to 90.3 for clinopyroxene, and 52.4 to 82.8 for amphibole. Mg#'s vary with height and display abrupt reversals, which indicate open-system addition of new mafic magma. Eleven cyclic units were identified on the basis of evidence for injection of basaltic magma; these can be grouped into three megacyclic units. The abundance of orthopyroxene, and mineral compositional evidence for Fe enrichment within cyclic units, indicates that parental magmas were subalkaline and tholeiitic. Plagioclase in equilibrium with olivine ranges from An65 to An46, which precludes an arc-related magma source. Although the intrusion is approximately coeval with Keweenawan magmatism and with emplacement of diabasic dikes in western North America, it is dissimilar in detail to both suites of rocks. Nevertheless, its composition and geophysical setting are consistent with emplacement in an extensional tectonic environment.

scholarly journals Use of Organosilicon Compounds towards the Rational Design of Antiparasitic and Antiviral Drugs

1995 ◽  
Vol 2 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Gérard Déléris
Keyword(s):  
Reverse Transcriptase ◽  
Antisense Oligonucleotides ◽  
Rational Design ◽  
Chemical Properties ◽  
Therapeutic Agents ◽  
Main Group ◽  
Biologically Active ◽  
Hiv Reverse Transcriptase ◽  
Antiparasitic Drugs ◽  
High Level

One of the major problems met for the conception of antiviral or antiparasitic drugs is to reach a high level of selectivity towards the pathogenic agent versus the host. We shall describe two synthetic approaches where main group organometallics have been used towards this goal. A series of nucleoside sila-analogues was synthesized as potential therapeutic agents designed to inhibit HIV Reverse Transcriptase. In a second approach novel organosilicon derivatives have been synthesized as mimics of antisense oligonucleotides.Infectious agents, namely viruses or parasites, more or less use cellular machinery. Therefore therapeutic agents must interfere with biochemical mechanisms or possess high affinity towards specific molecular cellular components, to reach selectivity.We thought that main group organometallics could show many advantages for designing biologically active molecules in this field. They allow a high synthetic flexibility for the modulations of physico-chemical properties and they show a mechanistic behaviour which may be close to the one of several heteroelements present in living organisms such as sulfur or phosphorus.We tried to use this approach towards two directions involving the synthesis of organosilicon derivatives i.e:-the synthesis of organosilicon derivatives as inhibitors of HIV Reverse Transcriptase,-the synthesis of organosilicon precursors of modified antisense oligonucleotides.

GEOCHEMISTRY OF THE YELLOWKNIFE VOLCANIC ROCKS

1966 ◽  
Vol 3 (1) ◽  
pp. 9-30 ◽  
Author(s):  
W. R. A. Baragar
Keyword(s):  
Bulk Composition ◽  
Volcanic Rocks ◽  
River Section ◽  
Magma Chambers ◽  
Tholeiitic Magma ◽  
Composite Form ◽  
High Level ◽  
Mafic Lavas ◽  
Stratigraphic Height ◽  
Volcanic Cycles

Results of rapid-method chemical analyses of samples taken at about 500-ft stratigraphic intervals through two sections of Yellowknife Group volcanic rocks are presented in graphical and composite form. The Yellowknife section is about 40 000 ft thick with the base undefined; the Cameron River section, about 45 mi northeast, is about 7 000 ft thick and may be complete.Two aspects of the volcanic chemistry considered are (1) variation in composition with stratigraphic height; (2) bulk composition of the volcanic rocks.Chemical data of the Yellowknife section define two volcanic cycles in each of which mafic lavas show a small but significant increase in sialic components with stratigraphic height culminating abruptly in acidic layers. The Cameron River section shows a similar but less well-defined trend. Iron–magnesium ratios stage a succession of systematic increases, each persisting for a few thousand stratigraphic feet, but no overall systematic variation. The two types of chemical variation correspond to calc-alkali and tholeiitic differentiation trends respectively. The tholeiitic trend is attributed to fractionation in high-level magma chambers, demonstrated for Yellowknife magma by the Kam Point sill, and the calc-alkali trend to contamination of tholeiitic magma by sialic crust.Frequency distribution diagrams show Yellowknife volcanic rocks to be similar to Chayes' circumoceanic basalts in TiO2, CaO, and MgO and to his oceanic basalts in Al2O3. The characteristic rock type is basalt.

Precise U–Pb zircon dates from the Avalon Terrane in Newfoundland

1988 ◽  
Vol 25 (3) ◽  
pp. 442-453 ◽  
Author(s):  
T. E. Krogh ◽  
D. F. Strong ◽  
S. J. O'Brien ◽  
V. S. Papezik
Keyword(s):  
North America ◽  
High Precision ◽  
Western Europe ◽  
Main Group ◽  
Eastern North America ◽  
Broad Area ◽  
Separate Event ◽  
Pan African ◽  
Intrusive Rocks ◽  
Group Flow

The following new U–Pb dates are provided for zircons from volcanic and intrusive rocks of the Avalon Terrane of Newfoundland: Burin Group ophiolite (Wandsworth pegmatitic gabbro), [Formula: see text]; Marystown Group ash-flow tuff, [Formula: see text]; Rock Harbour Group rhyolite clast in conglomerate, [Formula: see text]; Harbour Main Group ash-flow tuff, [Formula: see text]; Harbour Main Group flow-banded rhyolite, [Formula: see text]; porphyritic rhyolite plug intruding Harbour Main Group, 632 ± 2 Ma; Holyrood Granite, [Formula: see text]; rhyolite dyke, Harbour Main Group, [Formula: see text]; and welded ash-flow tuff, "Grand Beach porphyry," [Formula: see text]. All of the dated zircons are simple, single-age populations with no trace of inheritance. These dates confirm that the ophiolitic Burin Group represents an older and separate event that correlates precisely with the Bou Azzer ophiolite of Morocco and that the Rock Harbour Group does not represent continental volcanism that preceded that event. The Rock Harbour, Marystown, and Harbour Main groups and the Holyrood Granite (632–608 Ma) are all part of the younger 650–550 Ma pulse of Pan-African orogenesis that affected a broad area extending through Africa, Asia, western Europe, southern England and Wales, and eastern North America. However, a shortage of high-precision dates throughout these terranes precludes very exact correlations and thus very exact interpretations in terms of specific tectonic or magmatic events. Although these dates require some revisions in the stratigraphy of the Newfoundland Avalon Terrane, they do not support suggestions that the Avalon Terrane comprises a "collage of suspect terranes." The age of the Grand Beach porphyry (394 Ma) places it squarely with the Acadian granites of the Appalachians and removes it from consideration as part of the Marystown Group.

scholarly journals Modern depressive disorder phenomena associated with suicidal male behavior

2020 ◽  
Vol 86 (1) ◽  
pp. 46-50
Author(s):  
G. Koltsova
Keyword(s):  
Suicidal Behavior ◽  
Depressive Disorders ◽  
Severe Depression ◽  
Main Group ◽  
Anxiety And Depression ◽  
Control Group ◽  
Self Awareness ◽  
Comprehensive Survey ◽  
High Level ◽  
Severe Anxiety

It was conducted a comprehensive survey of 100 men with depressive disorders. The clinical, psychopathological and pathopsychological features of depressive disorders associated with suicidal behavior in men were analyzed. All subjects were divided into two groups: the main group consisted of 51 patients with signs of suicidal behavior, control group consisted of 49 patients without signs of suicidal behavior. It has been shown that the clinical structure of depressive disorders is presented by sad (in 35.5 % of patients in the main group and in 34.7 % of control group), emotionally labile (in 29.9 % and in 31.3 %, respectively) and apathetic (in 34.6 % and in 34.0 %) variants. It has been established, that men with depressive disorders associated with self-destructive behavior have a high level of suicidal risk, low self-awareness of death, major or moderate depressive episode by MADRS, severe depression by HAM-D, clinically severe anxiety and depression by HADS, presence of serious suicidal intentions on the Columbian scale. Suicidogenic factors in men with depressive disorders are frustration of basic needs, loss of targeted personality installations and alcohol consumption. Keywords: depressive disorders, depression, anxiety, suicidal behavior.

scholarly journals Psychodiagnostics of suicide

2019 ◽  
pp. 3-9
Author(s):  
G. K. Dzub ◽  
V. A. Protzyc ◽  
V. A. Protzyc
Keyword(s):  
Depressive Disorders ◽  
Self Esteem ◽  
Psychological Research ◽  
Main Group ◽  
Control Group ◽  
Self Assessment ◽  
Suicidal Attempts ◽  
The Difference ◽  
High Level ◽  
And Control

An original hypothesis for the detection of suicidal readiness has been proposed: the dissociation between low self-esteem of personal qualitiesand high level of claims in behavior exists in all types of suicides. The main point is that suicide occurs in a situation where environmental conditions are appear to be completely incompatible with a person’s self-esteem; preserving the personality then the protective adaptive response of the personality is accomplished in the most radical way – self-destruction. Therefore, to detect readiness for suicide, you can use the methods of experimental psychological (psychodiagnostic) research. These are methods of self-assessment of a situation, that is, a tests assessing one's own merits and determining the level of claims in behavior. Discrepancies in the performance of these tests will reflect the degree of readiness for suicide. Confirmation has been obtained through clinical and experimental psychological research. On the material of 240 subjects, the modified methods of Dembo – Rubinstein and Hoppe were used. The main group consisted of 160 persons who committed suicidal attempts, of which 98 women and 62 men, average age (41.0 ± 9.7) years, including 86 with depressive disorders, 46 with neurotic disorders and 28 mentally healthy. In the control group there were 80 healthy individuals who did not commit suicidal attempts, with identical gender balance, average age and social status. The modification of the methods was that the results were presented in quantitative terms in points. In the main group, the dissociation indicators between the high level of claims and low self-esteem according to the methods of Dembo – Rubinstein and F. Hoppe were 46.8 ± 4.6, and in the control group – 27.00 ± 5.24 (P < 0,001). The difference between dissociation in the main and control groups is very significant (P < 0,0005), a score of 40–45 points indicates a suicidal risk, and 50–55 and more confidently point to the upcoming suicide attempt. As a result, the hypothesis is confirmed and a valid method of predicting suicide or assessing the degree of its risk arises; the method is suitable for practical use.

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