scholarly journals Two‐Stage Mafic‐Felsic Magma Interactions and Related Magma Chamber Processes in the Arc Setting: An Example from the Enclave‐Bearing Calc‐alkaline Plutons, Chinese Altai

2021 ◽  
Author(s):  
Xing Cui ◽  
Min Sun ◽  
Guochun Zhao ◽  
Yunying Zhang ◽  
Jinlong Yao
Keyword(s):  
Magma Chamber ◽  
Felsic Magma ◽  
Calc Alkaline ◽  
Two Stage ◽  
Magma Chamber Processes ◽  
Arc Setting

A proposed model for the formation of reversely zoned plutons based on a study of the Lacorne Complex, Superior Province, Quebec

1987 ◽  
Vol 24 (12) ◽  
pp. 2506-2520 ◽  
Author(s):  
James Bourne ◽  
Daniel Danis
Keyword(s):  
Trace Element ◽  
Magma Chamber ◽  
Magma Mixing ◽  
Outer Zone ◽  
Stage Model ◽  
Calc Alkaline ◽  
Two Stage ◽  
The Third ◽  
Proposed Model ◽  
Reverse Zoning

The Lacorne Complex is a calc-alkaline mass of Archean age located in the Abitibi region of Quebec. The complex can be subdivided into three zones. The inner zone varies in composition from hornblende > biotite gabbro breccia to monzonite, with all rocks containing ≤ 5 % modal quartz. The outer zone rocks contain more than 5% modal quartz and range in composition from biotite > hornblende quartz diorite to granodiorite. The third zone, consisting of muscovite–biotite–garnet leucomonzogranite, is exposed only in the northwestern portion of the complex. The transition between each zone is relatively abrupt but continuous. Based on 400 modal estimates of stained slabs and 107 whole-rock and trace-element analyses, it is demonstrated that both the inner zone and the outer zone rocks are reversely zoned: mafic cores are surrounded by more felsic borders. Various methods that could explain the observed geochemical trends are considered. The data indicate that crystal–liquid equilibria were maintained during crystallization and that mechanisms such as magma mixing can be rejected. A two-stage model involving sidewall crystallization and upwelling of fractionated magma accumulating near the roof of the magma chamber is proposed to explain the reverse zoning.

PETROCHEMISTRY AND MAGMA CHAMBER PROCESSES OF THE PERUVIAN COASTAL BATHOLITH GRANITES IN THE NORTHERN PART OF THE AREQUIPA SEGMENT

2016 ◽  
Author(s):  
Ana Maria Martinez ◽  
◽  
Benjamin L. Clausen ◽  
Scott R. Paterson ◽  
Vali Memeti
Keyword(s):  
Magma Chamber ◽  
Magma Chamber Processes

scholarly journals Editorial for the Special Issue “Mineral Textural and Compositional Variations as a Tool for Understanding Magmatic Processes”

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Silvio Mollo ◽  
Flavio Di Stefano ◽  
Francesca Forni
Keyword(s):  
Magma Chamber ◽  
Igneous Rocks ◽  
Eruption Dynamics ◽  
Special Issue ◽  
Magma Chamber Processes ◽  
Magmatic Processes ◽  
Compositional Variations

This Special Issue of Minerals collects seven different scientific contributions highlighting how magma chamber processes and eruption dynamics studied either in the laboratory or in nature may ultimately control the evolutionary histories and geochemical complexities of igneous rocks [...]

scholarly journals Petrogenesis of the synplutonic high-magnesian porphyritic dykes from the mafic-granitoid plutons of the East-European Craton, Voronezh crystalline massif

2019 ◽  
Vol 64 (4) ◽  
pp. 356-371
Author(s):  
R. A. Terentiev
Keyword(s):  
Trace Elements ◽  
Magma Chamber ◽  
Earth Element ◽  
Parent Magma ◽  
Chrome Spinel ◽  
Calc Alkaline ◽  
East European ◽  
Fine Grained ◽  
Mineral Inclusions ◽  
Metasomatized Mantle

This paper documents the data on high-Mg porphyrite dykes (PDs) from the mafic to felsic (~2.09 Ma) plutons of Elan complex (EC). The low-thickness (first centimeters) synplutonic dykes are characterized by sharp straight contacts without visible chilling zones, in contrast to the larger (up to 119 m) dykes that have gradual transitions. The dykes are fresh, porphyritic (bronzite, Al-enstatite, labradorite) and has fine-grained mainly quartzo-feldspathic (+biotite, sulfides, accessories, ±hypersthene) matrix. Based on geochemistry data the PDs are intermediate rocks (SiO2 = 58.9–60.3 wt. %) and plot into calc-alkaline series with high magnesian of whole rock (Mg# ~0.7) and felsic (68.9–70.2 wt. %) matrix (Mg# ~0.5). The PDs show differentiated rare-earth element patterns with negligible Eu anomalies. The bronzite phenocrysts varying sizes are characterized by block zoning and contain irregular inclusions of olivine (Mg# ~0.85), clinopyroxene (Mg# ~0.88), phlogopite (Mg# up to 0.94), labradorite, chrome spinel, graphite and sulfides. The Al-enstatite phenocrysts are practically sterile with respect to trace elements and mineral inclusions. The geochemical features as well as diffusion zones, reaction rims, and resorbed faces of the phenocrysts such as orthopyroxene and plagioclase indicate processes of recrystallization and/or partial dissolution of nonequilibrium crystals in the melt and indicate intratelluric nature of the dyke phenocrysts that cores are inherited from the EC derivatives/cumulate. The mineral thermometry estimates are: (1) the parent magma starting temperatures of 1200–1400 °С and (2) the EC crystallization temperatures 1080–1155 °С, (3) the PD emplacement temperatures 910–1070 °С. The petrogenetic model supposes the generation of EC high-temperature magmas similar to boninites from an upper metasomatized mantle. The melt is contaminated with continental crust lithologies. It implies the half-way evolved magma chamber in the crust. The PD melt, as a result of ending of the half-way magma chamber evolution, was emplaced into the still unheated EC plutons.

Mineral chemistry and geothermobarometry of the Balıkesir Volcanites (NW Anatolia, Turkey) 

2021 ◽  
Author(s):  
Alp Ünal ◽  
Şafak Altunkaynak
Keyword(s):  
Mineral Composition ◽  
Magma Chamber ◽  
Magma Mixing ◽  
Textural Properties ◽  
Mineral Chemistry ◽  
Oscillatory Zoning ◽  
Magma Chamber Processes ◽  
Crystallization Conditions ◽  
Compositional Variations ◽  
Opaque Minerals

<p>Balıkesir Volcanites (BV) are included into the Balıkesir Volcanic Province and contain various products of Oligo-Miocene volcanic activity in NW Anatolia. BV are formed from trachyandesite, andesite and dacite lavas with associated pyroclastic rocks. In this study, we report the petrographical investigations, mineral chemistry results and geothermobarometry calculations of the Balıkesir Volcanites in order to deduce the magma chamber processes and crystallization conditions. Andesites present a mineral composition of plagioclase (An35–50) + amphibole (edenitic hornblende) +biotite ± quartz and opaque minerals. The major phenocryst phases in dacite lavas are plagioclase (An39–53), quartz, amphibole (magnesio-hornblende), biotite, sanidine and opaque minerals. The mineral composition of the trachyandesites, on the other hand, is represented by plagioclase (An38–57) + amphibole (pargasitic hornblende) + biotite + clinopyroxene (endiopside- augite) ± sanidine ± quartz ± opaque minerals. Balıkesir Volcanites present distinct textural properties such as rounded plagioclase phenocrysts with reaction rims, oscillatory zoning, honeycomb and sieve textures in plagioclase, reverse mantled biotite and hornblende crystals. The plagioclase- amphibole geothermobarometry calculations of Balıkesir volcanites indicate that, andesite and dacite lavas present similar crystallization temperature and pressures conditions of 798- 813°C and 1,98- 2.17 kbar. Oppositely, trachyandesites were crystallized under 857°C and 3,72 kbar temperature and pressure conditions. These results show that the andesite and dacite lavas were originated from the same magma chamber with the depth of 7km whereas trachyandesites were evolved in a deeper magma chamber with 13 km depth. Combined mineral chemistry, petrography and geothermobarometry studies indicate that the open system processes such as magma mixing/mingling and/or assimilation fractional crystallization (AFC) were responsible for the textural and compositional variations of the Balıkesir Volcanites.</p>

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