scholarly journals The Panasqueira Rare Metal Granite Suites and Their Involvement in the Genesis of the World-Class Panasqueira W–Sn–Cu Vein Deposit: A Petrographic, Mineralogical, and Geochemical Study

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 562 ◽  
Author(s):  
Christian Marignac ◽  
Michel Cuney ◽  
Michel Cathelineau ◽  
Andreï Lecomte ◽  
Eleonora Carocci ◽  
...  

Elucidation of time-space relationships between a given wolframite deposit and the associated granites, the nature of the latter, and their alterations, is a prerequisite to establishing a genetic model. In the case of the world-class Panasqueira deposit, the problem is complicated because the associated granites are concealed and until now poorly known. The study of samples from a recent drill hole and a new gallery allowed a new approach of the Panasqueira granite system. Detailed petrographic, mineralogical, and geochemical studies were conducted, involving bulk major and trace analyses, BSE and CL imaging, EPMA, and SEM-EDS analyses of minerals. The apical part of the Pansqueira pluton consisted of a layered sequence of separate granite pulses, strongly affected by polyphase alteration. The use of pertinent geochemical diagrams (major and trace elements) facilitated the discrimination of magmatic and alteration trends. The studied samples were representative of a magmatic suite of the high-phosphorus peraluminous rare-metal granite type. The less fractionated members were porphyritic protolithionite granites (G1), the more evolved member was an albite-Li-muscovite rare metal granite (G4). Granites showed three types of alteration processes. Early muscovitisation (Ms0) affected the protolithionite in G1. Intense silicification affected the upper G4 cupola. Late muscovitisation (Fe–Li–Ms1) was pervasive in all facies, more intense in the G4 cupola, where quartz replacement yielded quartz-muscovite (pseudo-greisen) and muscovite only (episyenite) rocks. These alterations were prone to yield rare metals to the coeval quartz-wolframite veins.

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 548
Author(s):  
Lia N. Kogarko ◽  
Troels F. D. Nielsen

The Lovozero complex, Kola peninsula, Russia and the Ilímaussaq complex in Southwest Greenland are the largest known layered peralkaline intrusive complexes. Both host world-class deposits rich in REE and other high-tech elements. Both complexes expose spectacular layering with horizons rich in eudialyte group minerals (EGM). We present a detailed study of the composition and cryptic variations in cumulus EGM from Lovozero and a comparison with EGM from Ilímaussaq to further our understanding of peralkaline magma chambers processes. The geochemical signatures of Lovozero and Ilímaussaq EGM are distinct. In Lovozero EGMs are clearly enriched in Na + K, Mn, Ti, Sr and poorer Fe compared to EGM from Ilímaussaq, whereas the contents of ΣREE + Y and Cl are comparable. Ilímaussaq EGMs are depleted in Sr and Eu, which points to plagioclase fractionation and an olivine basaltic parent. The absence of negative Sr and Eu anomalies suggest a melanephelinitic parent for Lovozero. In Lovozero the cumulus EGMs shows decrease in Fe/Mn, Ti, Nb, Sr, Ba and all HREE up the magmatic layering, while REE + Y and Cl contents increase. In Lovozero EGM spectra show only a weak enrichment in LREE relative to HREE. The data demonstrates a systematic stratigraphic variation in major and trace elements compositions of liquidus EGM in the Eudialyte Complex, the latest and uppermost part of Lovozero. The distribution of elements follows a broadly linear trend. Despite intersample variations, the absence of abrupt changes in the trends suggests continuous crystallization and accumulation in the magma chamber. The crystallization was controlled by elemental distribution between EGM and coexisting melt during gravitational accumulation of crystals and/or mushes in a closed system. A different pattern is noted in the Ilimaussaq Complex. The elemental trends have variable steepness up the magmatic succession especially in the uppermost zones of the Complex. The differences between the two complexes are suggested to be related dynamics of the crystallization and accumulation processes in the magma chambers, such as arrival of new liquidus phases and redistributions by mush melts.


2021 ◽  
pp. 002216782110180
Author(s):  
Luke Hockley

This article explores what it means to feel film. It does so through an exploration of the interconnections between Bergson, Deleuze, and Jung. Central to the argument is the ontological status of the image in these different philosophical and psychological traditions. In particular, image is seen as an encapsulation of coming into being, or what Bergson terms durée. To feel film is to engage with its therapeutic capacity to bring us into being. In the consulting room and in the cinema, this process is embodied and in some way created either between client and therapist or viewer and screen. The elusive present moment is the site at which the past permeates the present, creating as it does feeling toned entry into the process of becoming. Jung thought of this as central to individuation and Bergson as central to being. Feeling film from this perspective becomes a way of finding ourselves in both the world of the film and in our individual psyche.


2020 ◽  
Vol 29 (1) ◽  
pp. 63-79
Author(s):  
Frida Hastrup

Dating back to medieval times, fruit cultivation in Hardanger in western Norway is rooted in what is portrayed as a perfect microclimate naturally yielding the best apples in the world. However, the viability of the comparatively minute Norwegian fruit trade is continuously threatened by competition from outside, spurring all kinds of initiatives and policies to make it sustainable. The Norwegian fruit landscape, in other words, is both the natural and perfect home of world-class fruit and a site for continuous, often state-driven interventions to make it so; indeed, the perfection of the place accentuates the need to do what it takes to make it thrive. The necessary means to accomplish such viability, however, make up a complex terrain, as the resourcefulness of the Norwegian fruit landscape is ‘measured’ according to very different units.


2021 ◽  
pp. 104433
Author(s):  
Sebastián Hreus ◽  
Jakub Výravský ◽  
Jan Cempírek ◽  
Karel Breiter ◽  
Michaela Vašinová Galiová ◽  
...  
Keyword(s):  

2009 ◽  
Vol 17 (2) ◽  
pp. 143-176 ◽  
Author(s):  
Rachel Adelman

AbstractThroughout the midrash Pirqe de-Rabbi Eliezer (PRE), motifs are recycled to connect primordial time to the eschaton. In this paper, I read passages on the well “created at twilight of the Sixth Day” in light of Bakhtin's notion of “chronotope” (lit. time-space). The author of PRE disengages the itinerant well from its traditional association with the desert sojourn and links it, instead, to the foundation stone of the world (even shtiyah) at the Temple Mount. The midrash reflects the influence of Islamic legends about the “white stone” around which the Dome of the Rock was built (ca. 690 C.E.). Over the course of the discussion, PRE is understood in terms of the genre “narrative midrash” and compared to classical rabbinic literature in order to illustrate changes in both form and content arising from the author's apocalyptic eschatology.


2020 ◽  
Vol 22 ◽  
pp. 385-397
Author(s):  
Tommaso Tuppini ◽  
Keyword(s):  

We typically conceive of sensation as a residue of empiricism and idealism, both of which claim to reduce our experience to a sum of elementary data that the subject encounters. For Merleau-Ponty, sensation is none of these things: it defines our ability to let ourselves be solicited by the relief and questions of the world. What is sensed is not an inert datum but a gesture of existence that concerns me, invites me to correspond to it and follow it. When I respond to the invitations of what I sense, the connection between me and the world functions as the immobile axis around which the whirls of a whirlwind are formed. Whirlwind of sensation or whirlwind of sleep, because sensing is also made of a night time-space in which the connection with things seem to be broken. The inertia of sleep is whirling in its own way, just as the dynamism of sensation has its own condition of possibility in an immeasurable measure of apathy and indifference.


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