Phlogopitization of pyroxenite; its bearing on the composition of carbonatite magmas

1975 ◽  
Vol 112 (5) ◽  
pp. 503-507 ◽  
Author(s):  
J. Gittins ◽  
C. R. Allen ◽  
A. F. Cooper
Keyword(s):  
Evolutionary History ◽  
Ultramafic Rock ◽  
Aqueous Fluid ◽  
Typical Development ◽  
Experimental Phase ◽  
Carbonatite Complex ◽  
History Of ◽  
The Common ◽  
Alumina Activity ◽  
Carbonatite Magma

SummaryPhlogopitization of pyroxenite is common in contact zones between clinopyroxenites and carbonatite dikes of the Cargill ultramafic rock—carbonatite complex near Kapuskasing, Ontario. The most typical development is a mica zone 1–10 cm wide but phlogopite is also developed in a more pervasive manner throughout the groundmass of several types of ultramafic rock. Fenitization is most commonly thought of as a process whereby aegirine and riebeckitic amphiboles are formed in the host rock while feldspar is recrystallized and silica progressively removed. Phlogopitization of pyroxenite can properly be referred to, however, as a type of fenitization. It is clearly related to the intrusion of carbonatite into pyroxenite and is further testimony to the fact that many carbonatite magmas are initially alkalic but lose alkalies to the surrounding rocks and crystallize as calcitic and dolomitic carbonatite with alkali contents restricted to the amounts that could be fixed as micas, pyroxenes or amphiboles. This in turn is controlled by the silica and alumina activity of the carbonatite magma. Abundant evidence for considerable amounts of fluorine in carbonatite magmas suggests that alkalies may be transported into the country rocks as fluorides. It is further suggested that late-stage feldspathization in carbonatite complexes is explained by the abstraction of potassic halide solutions from the crystallizing carbonatite magma. The conclusion seems inescapable that alkali carbonatite magmas, far from being the curiosity thought by many petrologists, are in fact very common during the evolutionary history of carbonatites. The common calcitic and dolomitic carbonatites have not generally crystallized from a magma of the same composition but are the residue remaining after the abstraction of an alkali-rich aqueous fluid. Consequently, there is a need to redesign the experimental phase equilibrium approach to problems of carbonatite genesis in order to take account of the presence of alkalies in most carbonatite magmas.

First North African record of a melanistic common genet (Genetta genetta Linnaeus, 1758)

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mourad Ahmim ◽  
Hafid Aroudj ◽  
Farouk Aroudj ◽  
Saaid Saidi ◽  
Samir Aroudj
Keyword(s):  
North Africa ◽  
Evolutionary History ◽  
North African ◽  
Mammal Species ◽  
Genetta Genetta ◽  
History Of ◽  
The Common ◽  
True Occurrence

Abstract The common genet (Genetta genetta Linnaeus, 1758) is a rare and protected mammal species in Algeria. We report the first melanistic individual of this species ever recorded in North Africa. Such animals have only been recorded in Spain and Portugal so far. It is unclear why melanistic common genets seem to be so rare in its African range. More research is needed to determine the true occurrence of melanistic individuals, and what the evolutionary history of melanism is in common genets.

scholarly journals The evolutionary history of the two karyotypic groups of the common shrew, Sorex araneus, in Poland

Heredity ◽  
2002 ◽  
Vol 88 (4) ◽  
pp. 235-242 ◽  
Author(s):  
M Ratkiewicz ◽  
S Fedyk ◽  
A Banaszek ◽  
L Gielly ◽  
W Chȩtnicki ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Common Shrew ◽  
Sorex Araneus ◽  
History Of ◽  
The Common ◽  
Common Shrew Sorex Araneus

scholarly journals Tribalism Is Human Nature

2019 ◽  
Vol 28 (6) ◽  
pp. 587-592 ◽  
Author(s):  
Cory J. Clark ◽  
Brittany S. Liu ◽  
Bo M. Winegard ◽  
Peter H. Ditto
Keyword(s):  
Evolutionary History ◽  
Cognitive Biases ◽  
Meta Analysis ◽  
Human Cognition ◽  
Partisan Bias ◽  
Selective Pressures ◽  
Group Loyalty ◽  
History Of ◽  
The Common ◽  
Political Spectrum

Humans evolved in the context of intense intergroup competition, and groups comprised of loyal members more often succeeded than groups comprised of nonloyal members. Therefore, selective pressures have sculpted human minds to be tribal, and group loyalty and concomitant cognitive biases likely exist in all groups. Modern politics is one of the most salient forms of modern coalitional conflict and elicits substantial cognitive biases. The common evolutionary history of liberals and conservatives gives little reason to expect protribe biases to be higher on one side of the political spectrum than the other. This evolutionarily plausible null hypothesis has been supported by recent research. In a recent meta-analysis, liberals and conservatives showed similar levels of partisan bias, and several protribe cognitive tendencies often ascribed to conservatives (e.g., intolerance toward dissimilar other people) were found in similar degrees in liberals. We conclude that tribal bias is a natural and nearly ineradicable feature of human cognition and that no group—not even one’s own—is immune.

scholarly journals The evolutionary history of haptophytes and cryptophytes: phylogenomic evidence for separate origins

2012 ◽  
Vol 279 (1736) ◽  
pp. 2246-2254 ◽  
Author(s):  
Fabien Burki ◽  
Noriko Okamoto ◽  
Jean-François Pombert ◽  
Patrick J. Keeling
Keyword(s):  
Evolutionary History ◽  
Expressed Sequence Tag ◽  
Level Data ◽  
Guillardia Theta ◽  
History Of ◽  
The Common ◽  
Genome Level ◽  
Phylogenomic Analyses ◽  
New Hypothesis ◽  
Expressed Sequence

An important missing piece in the puzzle of how plastids spread across the eukaryotic tree of life is a robust evolutionary framework for the host lineages. Four assemblages are known to harbour plastids derived from red algae and, according to the controversial chromalveolate hypothesis, these all share a common ancestry. Phylogenomic analyses have consistently shown that stramenopiles and alveolates are closely related, but haptophytes and cryptophytes remain contentious; they have been proposed to branch together with several heterotrophic groups in the newly erected Hacrobia. Here, we tested this question by producing a large expressed sequence tag dataset for the katablepharid Roombia truncata , one of the last hacrobian lineages for which genome-level data are unavailable, and combined this dataset with the recently completed genome of the cryptophyte Guillardia theta to build an alignment composed of 258 genes. Our analyses strongly support haptophytes as sister to the SAR group, possibly together with telonemids and centrohelids. We also confirmed the common origin of katablepharids and cryptophytes, but these lineages were not related to other hacrobians; instead, they branch with plants. Our study resolves the evolutionary position of haptophytes, an ecologically critical component of the oceans, and proposes a new hypothesis for the origin of cryptophytes.

Bridging Darwin's Origin of Species & Wegener's Origin of Continents and Oceans:

2016 ◽  
Vol 78 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Cristina Sousa
Keyword(s):  
Evolutionary History ◽  
Charles Darwin ◽  
Common Ancestor ◽  
Teaching Strategy ◽  
Origin Of Species ◽  
History Of ◽  
The Common ◽  
Research And Education ◽  
Evolution By Natural Selection ◽  
Biology Research

The common ancestor and evolution by natural selection, concepts introduced by Charles Darwin, constitute the central core of biology research and education. However, students generally struggle to understand these concepts and commonly form misconceptions about them. To help teachers select the most revelant portions of Darwin's work, I suggest some sentences from On the Origin of Species and briefly discuss their implications. I also suggest a teaching strategy that uses history of science and curriculum crosscutting concepts (cause and effect) that constitute the framework to explain the evolutionary history of ratites (flightless birds) as described by Darwin, starting in the Jurassic, with the breakup of Gondwanaland, as first described by Alfred Wegener in The Origin of Continents and Oceans.

The common evolutionary history of badnaviruses and banana

2014 ◽  
Vol 21 ◽  
pp. 83-89 ◽  
Author(s):  
Marie-line Iskra-Caruana ◽  
Pierre-Olivier Duroy ◽  
Matthieu Chabannes ◽  
Emmanuelle Muller
Keyword(s):  
Evolutionary History ◽  
History Of ◽  
The Common

scholarly journals Protofeathers were likely to have existed within the common ancestor of dinosaurs

2015 ◽  
Author(s):  
Chan-gyu Yun
Keyword(s):  
Evolutionary History ◽  
Common Ancestor ◽  
Whole Body ◽  
Collagen Fibres ◽  
History Of ◽  
The Common

In this paper, I comment on Barrett et al. (2015) "Evolution of dinosaur epidermal structures". Though the original authors made some very interesting results, the conclusions made by them are likely influenced by inappropriate or incorrect assumptions such as very little preserved skin fragments represent whole body covering or dinosaurian integumentary structures might represent a degraded collagen fibres. Therefore, their result might represent small size of current datas or preservational bias rather than actual evolutionary history of dinosaurian feathers.

Religion in the Perspective of“Big History”

2014 ◽  
Vol 107 (1) ◽  
pp. 114-126
Author(s):  
S. Mark Heim
Keyword(s):  
Evolutionary History ◽  
Human Species ◽  
History Of ◽  
First Millennium ◽  
Robert Bellah ◽  
Magnum Opus ◽  
The Common ◽  
American Society ◽  
Common Era ◽  
Primordial Soup

At the pinnacle of his career, the renowned sociologist Robert Bellah did not choose to write a magnum opus refining the influential work of a lifetime, focused particularly on contemporary American society. Nor did he choose to offer an unbuttoned reflection on the future of his discipline or the culture he had so closely studied. Instead, he devoted thirteen years to a project of breathtaking scope, religion in the evolutionary history of the human species, from the primordial soup to the Dalai Lama. He asked where religion had come from, not where it was going. He eventually felt compelled to truncate this story at the “axial age,” in the first millennium before the Common Era. This 700-page “fragment” of the original vision (before his recent death, he held out hope for a smaller companion book to round it off) is a work of judicious audacity. It is high tribute to Bellah's intellect and industry that it merits the first modifier no less than the second.

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