scholarly journals PETROGRAPHY AND MINERAL CHEMISTRY OF OLIGOCENE SHOSHONITIC DACITES FROM THE CENTRAL BOSNIA

2020 ◽  
Vol 1 (22) ◽  
Author(s):  
Zehra Salkić ◽  
Boško Lugović ◽  
Elvir Babajić
Keyword(s):  
Pannonian Basin ◽  
Magma Mixing ◽  
Volcanic Rocks ◽  
Mafic Magma ◽  
Mineral Chemistry ◽  
Southeastern Part ◽  
Vardar Zone ◽  
High K ◽  
Insight Into ◽  
Zoned Plagioclase

Postorogenic volcanic rocks of different Tertiary ages are very common in the Sava-Vardar Zone of the Dinarides and in the southeastern part of adjoing Pannonian Basin. South of the Sava-Vardar Zone, in central Bosnia, Tertiary volcanic rocks occur within ophiolite sequences and genetically related sedimentary formations of the Dinaride Ophiolite Zone. Central Bosnia volcanic rocks are mostly dacites, and highly subordinately andesites as the members of the high-K calc-alkaline series.It appears from the mineralogical and petrographic characteristics obtained some insight into the processes that occurred during the genesis of the rocks. The presence of primary igneous minerals: clinopyroxene, orthopyroxene, hornblende and biotite from ferromagnesian minerals, and plagioclase, sanidine and quartz, indicates that the fractional crystallization played a significant role in the genesis of the rocks. Reaction edge on many rounded quartz phenocrysts indicates the possibility of magma mixing with the formation of Tertiary volcanic rocks of the central Bosnia. On magma mixing different temperature and chemical composition also indicates the existence of zoned plagioclase and amphibole phenocrysts.Complex compositional and zoning patterns of biotite and plagioclase phenocrysts and disequilibrium microstructures of plagioclase and quartz phenocrysts suggest interaction of fractionating, mantle derived melts with continental crust during a shalow level pre-eruptive stage and mixing with small amount of devolatilized phlogopite-phyric mafic magma before eruption.

scholarly journals Mineral Chemistry Studies and Evidences For Magma Mixing of Bala Zard Basic- Intermediate Volcanic Rocks, Lut Block, Iran

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 1194-1205 ◽  
Author(s):  
Omid Namin ◽  
Afshin Ardalan ◽  
Mohammad Razavi ◽  
Arash Gourabjeripour ◽  
Abdollah Yazdi
Keyword(s):  
Magma Mixing ◽  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Lut Block

Mineral chemistry of perpotassic lavas of the Vulsinian district, the Roman Province, Italy

1982 ◽  
Vol 46 (340) ◽  
pp. 379-386 ◽  
Author(s):  
Paul M. Holm
Keyword(s):  
Magma Mixing ◽  
Volcanic Rocks ◽  
Alkali Feldspar ◽  
Mineral Chemistry ◽  
Low Pressure ◽  
Major Elements ◽  
Crystal Fractionation ◽  
High Concentrations ◽  
Roman Province ◽  
Pressure Crystallization

SynopsisThe Vulsinian district is the largest and northernmost of the Roman Provinces. There is very little modern mineralogical data on the Italian Pliocene to Recent perpotassic alkaline volcanic rocks and this account deals with the compositions of the phenocrysts in the Vulsinian lavas.The lavas comprise two suites: a leueite-bearing undersaturated series of leucitites, leueite tephrites, leucite phonolites, and trachytes; and a subordinate hy-normative series of mainly trachytes and latites. All lavas are porphyritic with mostly 1–15 vol. % phenoerysts. No cumulates were found. Major elements, and Cr and Ni were determined in the phenocrysts by microprobe analysis and more than 20 trace elements were determined on mineral separates by PIXE.The undersaturated suite. Ubiquitous clinopyroxene phenoerysts belong to the Di-Hedss series and range from Di97 to Di46. Important amounts of Fe3+ are always present. In the mafic rocks the diopside is chromian, but Ti is low. AI mainly substitutes in the Z positions in all lavas. Only minor Na enrichment occurs with increasing total Fe (0–7 mole % acmite) and thus Ca ferri-Tschermak's component is important. In many of the maric lavas diopside mantles green cores of salite, which has a composition very like the salite of felsic lavas. Leucites contain 5–22 mole % orthoelase in solid solution, but show no systematic variation. Plagioclase, mostly An93-An72, occurs in the felsie lavas, and alkali feldspar only in some phonolites. They both have exceptionally high concentrations of Sr and Ba, with a maximum of 1.3 wt. % SrO and 5.6 wt. % BaO in hyalophanes. Olivine, Fo92-Fo66, occurs in some leucititic lavas in mostly accessory amounts. Phlognpite, magnetite and nepheline are accessory phases of the felsic lavas. Apatite only occur as micro-phenocrysts of the fclsic lavas. Haüyne in trace amounts is found in a few phonolites. Pargasitic amphibole microphenocrysts are found in one lava.In most marie members diopside ±leuctie ±olivine were liquidus phases. This study does not confirm that these rocks are related by crystal fractionation. In more felsie lavas clinopyroxene (salite-ferrosalite) and leucite are joined by: plagioclase, magnetite ±phlogopite, and Ba-rich alkali feldspar ±haüyne. The felsic rocks are thought to be related by crystal fractionation.Salitic green cores of phenocrystic pyroxene, mantled by diopside in rocks which also carry normally-zoned diopside, are relicts which provide evidence of either a relatively high PH2O, prior to the crystallization of diopside or magma mixing in the earlier life of these lavas. Pyroxene chemistry points towards low-pressure crystallization (2 kbar), generally in a dry environment.The hy-normative suite. All lavas have phenocrysts of augite, sanidine, plagioclase, magnetite, biotite, and olivine. The pyroxene is less calcic and has less alumina, but is otherwise rather similar to the salites of the undersaturated suite. Compared to the undersaturated suite, feldspars do not have high Sr and Ba, magnetite has higher TiO2 and olivine crystallized from even the felsic lavas. The pyroxenes show the signs of low-pressure crystallization.

Perovskite from the Dutoitspan kimberlite, Kimberley, South Africa: implications for magmatic processes

2009 ◽  
Vol 73 (6) ◽  
pp. 915-928 ◽  
Author(s):  
R. C. Ogilvie-Harris ◽  
M. Field ◽  
R. S. J. Sparks ◽  
M. J. Walter
Keyword(s):  
South Africa ◽  
Magma Mixing ◽  
Mineral Chemistry ◽  
Minor Components ◽  
Sharp Boundary ◽  
Volatile Content ◽  
Wide Range ◽  
The Relationship ◽  
Diamondiferous Kimberlite ◽  
Insight Into

AbstractPerovskite compositions are used to investigate the relationship between the minor components (i.e. LREE, Fe3+ and Nb) and the oxygen fugacity (fo2) of perovskite in four different kimberlite lithofacies from the Dutoitspan pipe, Kimberley, South Africa, which range from diamondiferous to barren. The perovskite textures and chemical variations provide insight into magmatic and eruptive processes. Some crystals display cores with rims separated by a sharp boundary. The cores contain larger Na and LREE contents relative to the rims, which show a large increase in Fe3+ and Al. The mid-grade and barren kimberlites have bi-modal cores, reflected in the mineral chemistry, signifying multiple batches of magma and magma mixing. The fo2 of the magma is determined by an Fe-Nb oxygen barometer. The most diamondiferous kimberlite has the greatest Fe3+ content and highest fo2 (NNO –3.6 to –1.1). The kimberlite containing large diamonds has the smallest Fe3+ content and lowest fo2 (NNO –5.2 to –3.0). The barren and mid-grade kimberlites display a wide range of fo2,(NNO –5.3 to –1.5) as a result of perovskites forming in different melts and subsequently mixing together. Chemical and petrological evidence suggests that the volatile content, degassing, decompression and rate of crystallization can influence the rate at which the magma is erupted. One possibility is that the most oxidized magma, containing the highest volatile content, is therefore erupted much more rapidly, preserving diamond as a consequence.

Mineralogical Evidence of Pre-caldera Magma Petrogenesis in the Jemez Mountains Volcanic Field, New Mexico, USA

2020 ◽  
Vol 61 (7) ◽  
Author(s):  
Jie Wu ◽  
Michael C Rowe ◽  
Shane J Cronin ◽  
John A Wolff
Keyword(s):  
Low Temperature ◽  
Magma Mixing ◽  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Volcanic Field ◽  
Magmatic System ◽  
Upward Migration ◽  
Jemez Mountains ◽  
Almost All ◽  
Shallow Crust

Abstract The Jemez Mountains volcanic field (JMVF) is the site of the two voluminous, caldera-forming members of the Bandelier Tuff, erupted at 1·60 and 1·25 Ma, following a long and continuous pre-caldera volcanic history (∼10 Myr) in this region. Previous investigations utilizing whole-rock geochemistry identified complex magmatic processes in the two major pulses of pre-caldera magmatism including assimilation–fractional crystallization (AFC) and magma mixing. Here we extend the petrological investigation of the pre-caldera volcanic rocks into the micro-realm and use mineral chemistry and textural information to refine magma evolution models. The results show an increasing diversity of mineral populations as the volcanic field evolved. A range of plagioclase textures (e.g. sieved cores and rims) indicate disequilibrium conditions in almost all pre-caldera magmas ranging from andesite to rhyolite, reflecting plagioclase dissolution and regrowth. Coarsely sieved or dissolved plagioclase cores are explained by resorption via water-undersaturated decompression during upward migration from a deep melting, assimilation, storage and homogenization (MASH) zone. Plagioclase crystals with sieved rims are almost ubiquitous in dacite-dominated magmatism (La Grulla Plateau andesite and dacite erupted at ∼8–7 Ma, as well as Tschicoma Formation andesite, dacite and rhyolite at ∼5–2 Ma), reflecting heating induced by magma mixing. These plagioclase crystals often have An-poor cores that are chemically distinct from their An-rich rims. The existence of different plagioclase populations is consistent with two distinct amphibole groups that co-crystallized with plagioclase: a low-Al, low-temperature, high-fO2 group, and a high-Al, high-temperature, low-fO2 group. Calculation of melt Sr, Ba, La, and Ce concentrations from plagioclase core and rim compositions suggests that these chemical variations are largely produced by magma mixing. Multiple mafic endmembers were identified that may be connected by AFC processes in the MASH zone in the middle to lower crust. The silicic component in an early andesite-dominated magmatic system (Paliza Canyon andesite, dacite and rhyolite, 10–7 Ma) is represented by contemporaneous early rhyolite (Canovas Canyon Rhyolite). A silicic mush zone in the shallow crust is inferred as both the silicic endmember involved in the dacite-dominant magmatic systems and source of the late low-temperature rhyolite (Bearhead Rhyolite, 7–6 Ma). Recharging of the silicic mush by mafic melts can explain observed diversity in both mineral disequilibrium textures and compositions in the dacitic magmas. Overall, the pre-caldera JMVF magmatic system evolved towards cooler and more oxidized conditions with time, indicating gradual thermal maturation of local crust, building up to a transcrustal magmatic system, which culminated in ‘super-scale’ silicic volcanism. Such conditioning of crust with heat and mass by early magmatism might be common in other long-lived volcanic fields.

scholarly journals PETROLOGY - GEOCHEMISTRY AND METALLOGENESIS OF VOLCANIC ROCKS IN THE PETROTA GRABEN/MARONIA, W.THRACE

2004 ◽  
Vol 36 (1) ◽  
pp. 482 ◽  
Author(s):  
Κ. Αρίκας ◽  
Π. Βουδούρης ◽  
M. R. Kloos ◽  
Ch. Tesch
Keyword(s):  
Fractional Crystallization ◽  
Magma Mixing ◽  
Volcanic Rocks ◽  
Calc Alkaline ◽  
Mixing Processes ◽  
Geochemical Study ◽  
High K

The penological, mineralogical and geochemical study of tertiary volcanic rocks from Petrota Graben/Maronia, resulted in the distinction of the following pétrographie groups: a) a high-K calcalkaline group (andesites-dacites), b) a shoshonitic group (shoshonitic andésites, trachytic lavas, c) rhyodacitic ignimbrites and ignimbritic tuffs with high-K calc-alkaline to shoshonitic affinity, and d) rhyolites. The shoshonitic volcanic rocks and the rhyolites are probably originated from the neighbouring Maronia plutonio complex. In addition the calc-alkaline group is related to similar volcanics outcroping in the Mesti-Kassiteres area (the northeastern extension of the Graben). The petrogenesis of the volcanic rocks of the Petrota gragen is attibuted to fractional crystallization and/or magma mixing processes. Epithermal style mineralizations in Mavrokoryfi, Perama Hill and Odontoto are believed to be genetically related to the rhyolitic magmatism in the area.

Geochemistry and geodynamic constraint of volcanic and plutonic magmatism within the Banfora Belt (Burkina-Faso, West-Africa): contribution to mineral exploration

2020 ◽  
pp. SP502-2019-86
Author(s):  
Hermann Ilboudo ◽  
Sâga Sawadogo ◽  
Gounwendmanaghre Hubert Zongo ◽  
Seta Naba ◽  
Urbain Wenmenga ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Mineral Exploration ◽  
Volcanic Rocks ◽  
Mafic Magma ◽  
Calc Alkaline ◽  
High K ◽  
Tectonic Settings ◽  
Arc Setting ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

AbstractPredominant volcano-plutonic (mafic–felsic) activity is expressed in the eastern Banfora Belt. The geochemical signature shows different geodynamic settings: (1) mafic rocks are tholeiitic, subalkaline and show high-Mg tendency, whereas pyroxenolite (MgO c. 15.4 wt%) has komatiite affinity; (2) felsic volcanic rocks are subalkaline; and (3) granitoids surrounding the Banfora Belt are alkaline to calc-alkaline, high K, peraluminous to metaluminous. The geochemistry of mafic volcanic rocks shows an unusual evolution from Mid Oceanic Ridge Basalt to Arc-related. The Western Granite and Eastern Granites were emplaced by fractional crystallization and partial melting, respectively, but sourced from igneous protolith (I-type magma) in a volcanic arc setting. The Sodingue granite was emplaced by fractional crystallization from A-type magma in a ‘within-plate setting’. Two-mica S-type granites located at the central portion of the belt relate to syn-collisional fractional crystallization. The paper highlights the complexity of the magma process through a diversity of sources, geochemical patterns and tectonic settings. An emphasis on the komatiite affinity of mafic magma is a challenge for related commodities, such as copper and gold resources.

Evidence for mixed contribution of mantle and lower and upper crust to the genesis of Jurassic I-type granites from Macao, SE China

2020 ◽  
Vol 133 (1-2) ◽  
pp. 37-56 ◽  
Author(s):  
Pedro Quelhas ◽  
João Mata ◽  
Ágata Alveirinho Dias
Keyword(s):  
Magma Mixing ◽  
Mineral Chemistry ◽  
Granitic Rocks ◽  
Geochemical Data ◽  
Mafic Enclaves ◽  
Group I ◽  
High K ◽  
Depleted Mantle ◽  
Charge And Radius ◽  
Se China

Abstract Much controversy has occurred in the past few decades regarding the nature of the sources, the petrogenetic processes, and the tectonic regime(s) of the Jurassic magmatism within the Southeast China magmatic belt. This study aims to contribute to the discussion with mineral chemistry, and whole-rock element and Sr-Nd-Hf-Pb isotopic geochemical data from granitic rocks and microgranular mafic enclaves from Macao, where two discrete groups of I-type biotite granites have been identified (referred to as Macao Group I [MGI] and Macao Group II [MGII]). It is proposed that the granitic magmas were generated by partial melting of infracrustal medium- to high-K, basaltic Paleoproterozoic to Mesoproterozoic protoliths (Nd depleted mantle model age [TDM2] = 1.7–1.6 Ga and Hf TDM2 = 1.8–1.6 Ga), triggered by underplating of hot mantle-derived magmas in an extensional setting related to the foundering of a previously flat slab (paleo–Pacific plate) beneath the SE China continent. The main differences between the two groups of Macao granites are attributed to assimilation and fractional crystallization processes, during which upper-crustal Paleozoic metasediments were variably assimilated by MGI magmas. This is evidenced by an increase in initial 87Sr/86Sr ratios with degree of evolution, presence of metasedimentary enclaves, and high percentage of zircon xenocrysts with Paleozoic ages. In addition, other processes like late-stage fluid/melt interaction and magma mixing also left some imprints on granite compositions (rare earth element tetrad effect plus non–charge-and-radius-controlled behavior of trace elements and decoupling between different isotope systems, respectively). The distribution of isotopically distinct granites in SE China reflects the nature of the two Cathaysia crustal blocks juxtaposed along the Zhenghe-Dapu fault.

scholarly journals Sustainable Modularity Approach to Facilities Development Based on Geothermal Energy Potential

2021 ◽  
Vol 11 (6) ◽  
pp. 2691
Author(s):  
Nataša Ćuković Ignjatović ◽  
Ana Vranješ ◽  
Dušan Ignjatović ◽  
Dejan Milenić ◽  
Olivera Krunić
Keyword(s):  
Geothermal Energy ◽  
Architectural Design ◽  
Pannonian Basin ◽  
Thermal Power ◽  
Chemical Compositions ◽  
Energy Potential ◽  
Southeastern Part ◽  
Geothermal Resources ◽  
Heating And Cooling ◽  
Different Temperatures

The study presented in this paper assessed the multidisciplinary approach of geothermal potential in the area of the most southeastern part of the Pannonian basin, focused on resources utilization. This study aims to present a method for the cascade use of geothermal energy as a source of thermal energy for space heating and cooling and as a resource for balneological purposes. Two particular sites were selected—one in a natural environment; the other within a small settlement. Geothermal resources come from different types of reservoirs having different temperatures and chemical compositions. At the first site, a geothermal spring with a temperature of 20.5 °C is considered for heat pump utilization, while at the second site, a geothermal well with a temperature of 54 °C is suitable for direct use. The calculated thermal power, which can be obtained from geothermal energy is in the range of 300 to 950 kW. The development concept was proposed with an architectural design to enable sustainable energy efficient development of wellness and spa/medical facilities that can be supported by local authorities. The resulting energy heating needs for different scenarios were 16–105 kW, which can be met in full by the use of geothermal energy.

scholarly journals Extreme isotopic heterogeneity in Samoan clinopyroxenes constrains sediment recycling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jenna V. Adams ◽  
Matthew G. Jackson ◽  
Frank J. Spera ◽  
Allison A. Price ◽  
Benjamin L. Byerly ◽  
...  
Keyword(s):  
Mantle Source ◽  
Magma Mixing ◽  
Major And Trace Elements ◽  
Mantle Heterogeneity ◽  
Isotopic Data ◽  
Nd Isotopes ◽  
Isotopic Heterogeneity ◽  
Total Variability ◽  
High Silica ◽  
Insight Into

AbstractLavas erupted at hotspot volcanoes provide evidence of mantle heterogeneity. Samoan Island lavas with high 87Sr/86Sr (>0.706) typify a mantle source incorporating ancient subducted sediments. To further characterize this source, we target a single high 87Sr/86Sr lava from Savai’i Island, Samoa for detailed analyses of 87Sr/86Sr and 143Nd/144Nd isotopes and major and trace elements on individual magmatic clinopyroxenes. We show the clinopyroxenes exhibit a remarkable range of 87Sr/86Sr—including the highest observed in an oceanic hotspot lava—encompassing ~30% of the oceanic mantle’s total variability. These new isotopic data, data from other Samoan lavas, and magma mixing calculations are consistent with clinopyroxene 87Sr/86Sr variability resulting from magma mixing between a high silica, high 87Sr/86Sr (up to 0.7316) magma, and a low silica, low 87Sr/86Sr magma. Results provide insight into the composition of magmas derived from a sediment-infiltrated mantle source and document the fate of sediment recycled into Earth’s mantle.

Early Cretaceous crust–mantle interaction linked to rollback of the Palaeo-Pacific flat-subducting slab: constraints from the intermediate–felsic volcanic rocks of the northern Great Xing’an Range, NE China

2021 ◽  
pp. 1-22
Author(s):  
Jia-Hao Jing ◽  
Hao Yang ◽  
Wen-Chun Ge ◽  
Yu Dong ◽  
Zheng Ji ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Volcanic Rocks ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Ne China ◽  
Asthenospheric Mantle ◽  
High K ◽  
Wide Range ◽  
Great Xing’An Range ◽  
Subducting Slab

Abstract Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time (c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵHf(t) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵHf(t) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.

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