scholarly journals Quaternary post-collision alkaline volcanism NW of Ahar (NW Iran): geochemical constraints of fractional crystallization process

2011 ◽  
Vol 62 (6) ◽  
pp. 547-562 ◽  
Author(s):  
Rahim Dabiri ◽  
Mohamad Emami ◽  
Habib Mollaei ◽  
Bin Chen ◽  
Mansor Abedini ◽  
...  
Keyword(s):  
Trace Element ◽  
Fractional Crystallization ◽  
Crystallization Process ◽  
Spinel Peridotite ◽  
Alkali Basalts ◽  
Nw Iran ◽  
Alkaline Volcanism ◽  
Nonlinear Trends ◽  
Geochemical Constraints ◽  
Fractional Crystallization Process

Quaternary post-collision alkaline volcanism NW of Ahar (NW Iran): geochemical constraints of fractional crystallization process Major and trace elements and Sr-Nd isotopic data are presented for the Quaternary alkaline volcanism NW of Ahar (NW Iran). The exposed rocks mainly consist of alkali basalts, trachybasalts, basaltic trachyandesites and trachyandesites. Alkali basalts and trachybasalts display microlithic porphyritic texture with phenocrysts of olivine, clinopyroxene, and plagioclase in microlithic groundmass. In the more evolved rocks (basaltic trachyandesites and trachyandesites), amphibole and biotite have appeared. Major and trace element abundances vary along continuous trends of decreasing MgO, TiO2, Fe2O3*, CaO, Co, Cr, V and Zn, and increasing K2O, Al2O3, Ba and Th with increasing SiO2. The Sr and Nd isotopic ratios vary from 0.704463 to 0.704921 and from 0.512649 to 0.512774, respectively. Alkali basalts with high 143Nd/144Nd ratio, low 87Sr/86Sr ratio and high MgO, Ni and Cr contents indicate that they were generated from relatively primitive magmas. Ba, Cr and La/Sm ratios versus Rb suggest that fractional crystallization of alkali basalts could have played a significant role in the formation of evolved rocks. Assimilation and fractional crystallization modelling, as well as Rb/Zr, Th/Yb and Ta/Yb ratios clearly indicate that crustal contamination accompanied by the fractional crystallization played an important role in petrogenesis of the trachyandesites. The small compositional differences between magma types, isotopic composition, mineralogy and nonlinear trends on Harker diagrams also indicate that magma mixing was not an essential process in the evolution of the Ahar magmas. Petrogenetic modelling has been used to constrain sources. Trace element ratio plots and REE modelling indicate that the alkali basalts were generated from a spinel-peridotite source via small degrees (~2.5%) of fractional melting.

Salt-forming regions of seawater type solution in the evaporation and fractional crystallization process

2014 ◽  
Vol 362 ◽  
pp. 281-287 ◽  
Author(s):  
Huan Zhou ◽  
Yanjuan Bao ◽  
Xiaoqin Bai ◽  
Ruoxin Ma ◽  
Lisha Huangfu ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Crystallization Process ◽  
Type Solution ◽  
Fractional Crystallization Process

scholarly journals O STOCK NEFELINA-SIENÍTICO RIO PARDO, PROVÍNCIA ALCALINA DO SUL DO ESTADO DA BAHIA

2012 ◽  
Author(s):  
Rita da Cunha Leal Menezes ◽  
Herbet Conceição ◽  
Maria de Lourdes da Silva Rosa ◽  
Marco Antonio Galarza ◽  
Débora Correia Rios ◽  
...  
Keyword(s):  
Rare Earth ◽  
Trace Element ◽  
Nepheline Syenite ◽  
Crystallization Process ◽  
The South ◽  
Trace Element Contents ◽  
Single Zircon ◽  
Age Range ◽  
Fractional Crystallization Process ◽  
Zircon Evaporation

O Stock Nefelina-Sienítico Rio Pardo se localiza na porção sul do conjunto de intrusões alcalinas que constitui a Província Alcalina do Sul do Estado da Bahia. Esse corpo aflora numa área de 46 km2, sendo constituído por sienito, sienito com nefelina, nefelina sienito e sodalita sienito. A idade Pb-Pb obtida em monocristal de zircão para esse stock foi de 725 ± 2 Ma, a qual se insere no intervalo de idades para o magmatismo da parte sul dessa província alcalina (732 Ma a 720 Ma). Os dados litoquímicos obtidos para esse stock o posicionam na suíte alcalina subsaturada em SiO2 da Província Alcalina do Sul do Estado da Bahia. Os conteúdos de elementos traços asseguram sua afinidade anorogênica. Sua evolução, controlada por cristalização fracionada, se marca por acentuado enriquecimento em Na2O (até 15%) e Al2O3 (até 25%) e marcantes decréscimos em SiO2 (63% a 45%) e Elementos Terras Raras.Palavras-chave: nefelina sienito, idade Pb-Pb, Rio Pardo, BahiaABSTRACT: THE RIO PARDO NEPHELINE-SYENITIC STOCK, SOUTH BAHIA ALKALINE PROVINCE. The Rio Pardo nepheline-syenitic intrusion is located in the southern sector of the South Bahia Alkaline Province. It crops out over an area of 46 km2 and consists of syenite, nepheline-bearing syenite, nepheline syenite and blue-sodalite syenite. The Pb-Pb single-zircon evaporation age of 725 ± 2 Ma obtained for the Rio Pardo stock is in agreement with the age range (732 Ma to 720 Ma) for the southern part of province. Lithochemical data provide evidence to consider the Rio Pardo stock as a body of the SiO2 sub-saturated alkaline suite of the South Bahia Alkaline Province. Trace element contents indicate anorogenic afinity and the stock evolution, controlled by a fractional crystallization process, resulted in an outstanding enrichment of Na2O (up to 15%) and Al2O3 (up to 25%), and an important depletion of SiO2 (63% to 45%) and Rare Earth Elements.Keywords: nepheline syenite, Pb-Pb age, Rio Pardo, Bahia State.,

Petrogenetic modelling of Quaternary post-collisional volcanism: a case study of central and eastern Anatolia

2004 ◽  
Vol 141 (1) ◽  
pp. 81-98 ◽  
Author(s):  
PINAR ALICI ŞEN ◽  
ABİDİN TEMEL ◽  
ALAIN GOURGAUD
Keyword(s):  
Trace Element ◽  
Mantle Source ◽  
Lithospheric Mantle ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Central Anatolia ◽  
Eastern Anatolia ◽  
Alkali Basalts ◽  
Alkaline Volcanism ◽  
Trace Elemental

Extensive continental collision-related volcanism occurred in Turkey during Neogene–Quaternary times. In central Anatolia, calc-alkaline to alkaline volcanism began in the Middle–Late Miocene. Here we report trace elemental and isotopic data from Quaternary age samples from central and eastern Anatolia. Most mafic lavas from central Anatolia are basalt and basaltic andesite, with lesser amounts of basaltic trachyandesite and andesite. All magma types exhibit enrichment in LILE (Sr, Rb, Ba and Pb) relative to HFSE (Nb, Ta). Trace element patterns are characteristic of continental margin volcanism with high Ba/Nb and Th/Nb ratios. 87Sr/86Sr and 143Nd/144Nd isotopic ratios of central Anatolian lavas range between 0.704105–0.705619 and 0.512604–0.512849, respectively. The Quaternary alkaline volcanism of eastern Anatolia has been closely linked to the collision between the Arabian and Eurasian plates. Karacadaǧ and Tendürek volcanic rocks are represented by alkali basalts and basaltic trachyandesites, respectively. As expected from their alkaline nature, they contain high abundances of LIL elements, but Tendürek lavas also show depletion in Nb and Ta, indicating the role of crustal contamination in the evolution of these magmas. 87Sr/86Sr and 143Nd/144Nd ratios of the Karacadaǧ and Tendürek lavas range from 0.703512 to 0.704466; 0.512742 to 0.512883 and 0.705743 to 0.705889 and 0.512676, respectively. Petrogenetic modelling has been used to constrain source characteristics for the central and eastern Anatolian volcanic rocks. Trace element ratio plots and REE modelling indicate that the central Anatolian volcanism was generated from a lithospheric mantle source that recorded the previous subduction events between Afro-Arabian and Eurasian plates during Eocene to Miocene times. In contrast, The Karacadaǧ alkaline basaltic volcanism on the Arabian foreland is derived from an OIB-like mantle source with limited crustal contamination. Tendürek volcanism, located on thickened crust, north of the Bitlis thrust zone, derived from the lithospheric mantle via small degrees (1.5 %) of partial melting.

scholarly journals Caracterização Petrográfica e Geoquímica da Parte Leste do Granito Europa, Distrito Mineiro de Pitinga, AM

2007 ◽  
Vol 34 (1) ◽  
pp. 77 ◽  
Author(s):  
MAURÍCIO PRADO ◽  
JOSÉ TADEU MAXIMINO MIRRAS FERRON ◽  
EVANDRO FERNANDES DE LIMA ◽  
ARTUR CEZAR BASTOS NETO ◽  
VITOR PAULO PEREIRA ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Genetic Relationship ◽  
Crystallization Process ◽  
Volcanic Rocks ◽  
Alkali Feldspar ◽  
Mineral Deposits ◽  
Geochemical Data ◽  
Principal Mechanism ◽  
Amazonian Region ◽  
Fractional Crystallization Process

The important mineral deposits of the Pitinga Mine, in the Amazonian region are related to A-type granites intruded in the Iricoumé Group. The Europa granite is one of these A-type rocks, intruded in the Iricoumé Group, which is represented by subaerial vulcanoclastic rocks (crystal-rich ignimbrites, thin massive tuffs and siltic tufaceous arenites) and minor hipabissal rhyolites. The volcanic rocks were probably generated in a caldera environment. The Europa granite is an alkali-feldspar peralkaline granite (hipersolvus) without genetic relationship with to the volcanic rocks of the Iricoumé Group, but it could have been generated during the resurgence stages. The petrographic and geochemical data attest that fractional crystallization process was the principal mechanism during the crystallization, which led to the generation of two different granitic facies. The Nb soil anomalies overprinted on the more differentiated facies are related to the astrophillite weathering.

Etude geochimique des elements en traces dans les series de roches volcaniques du rift d'Asal; identification et analyse des processus d'accretion

1980 ◽  
Vol S7-XXII (6) ◽  
pp. 851-861 ◽  
Author(s):  
J. L. Joron ◽  
M. Treuil ◽  
H. Jaffrezic ◽  
B. Villemant
Keyword(s):  
Partial Melting ◽  
Fractional Crystallization ◽  
Closed System ◽  
Mantle Source ◽  
Crystallization Process ◽  
Tectonic Activity ◽  
Dynamic Evolution ◽  
Mantle Material ◽  
Spreading Rates ◽  
Fractional Crystallization Process

Abstract Study of samples of the main volcanic units of the Afar rift, from margins to late axial series, have yielded the following conclusions: 1) the magmatic liquids are strongly differentiated by a fractional crystallization process in shallow chambers, the evolution of which is limited by injection of new primary liquids as shown in the latest axial series; 2) primary liquids are generated by melting of a homogeneous mantle source, a process whereby successive partial melting in a closed system is stopped by percolation of the generated liquid. The degrees of partial melting are closely related to spreading rates; 3) the magmatic processes involve a discontinuous dynamic evolution of spreading displayed by a pulsatory magmato-tectonic activity which is controlled by the speed of decompression of mantle material.

scholarly journals Effect of coolant temperature and cooling time on fractional crystallization of biodiesel and glycerol

2017 ◽  
Vol 13 (4) ◽  
pp. 676-679
Author(s):  
Shafirah Samsuri ◽  
Nurul Aini Amran ◽  
Loh Jia Zheng ◽  
Muhammad Muhaimin Mohd Bakri
Keyword(s):  
Methyl Ester ◽  
Fractional Crystallization ◽  
Crystallization Process ◽  
Current Method ◽  
Cooling Time ◽  
Coolant Temperature ◽  
Time Range ◽  
Separation And Purification ◽  
Wastewater Treatment Process ◽  
Fractional Crystallization Process

In the middle of the era of technology and fast-growing industry nowadays, biodiesel (methyl ester) has been identified as a sustainable fuel to replace petroleum. Hence, the separation and purification of the methyl ester after the trans-esterification process is essential since the purification of methyl ester is compulsory for the fuel industry in order to fulfill the strict global standard particulars for methyl ester. One of the current method used for separation and purification of methyl ester is called wet washing technology. However, this technology has its own drawbacks such as huge amount of water consumption as well as high cost for the wastewater treatment process. Due to these drawbacks, fractional crystallization process is proposed in order to save water and minimize the time consumed for the process of separation and purification of methyl ester. Fractional crystallization is a process that involved a solid-liquid separation where the process takes place in a crystallizer. In this process, methyl ester was separated from the glycerol based on their differences in term of melting point of the components. By observing the layer formation of the components, the effect of cooling time and coolant temperature on the performance of separation and purification of methyl ester by fractional crystallization process were studied. The purified methyl ester obtained was placed in a gas chromatographer in order to test the purity of methyl ester and to evaluate the efficiency of the process based on two parameters that has been investigated which are effective partition constant (K) and concentration efficiency (Eff). It was found that to achieve highest effectiveness of fractional crystallization system and highest concentration efficiency where K and Eff are 0.51 and 47.71%, respectively, the fractional crystallization must operate at coolant temperature range of -10 to -12ºC and cooling time range of 30 to 35 minutes.

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