Petrogenesis of the Cenozoic volcanic rocks in Baekdu volcano in northeastern Asia and the expected depth of the magma chamber based on geochemistry, mineral chemistry, and Sr-Nd-Pb isotope chemistry

Lithos ◽  
2021 ◽  
Vol 388-389 ◽  
pp. 106080
Author(s):  
Seung Hwan Lee ◽  
Chang Whan Oh ◽  
Youn Soo Lee ◽  
Seung-Gu Lee ◽  
Jia-qi Liu
Keyword(s):  
Magma Chamber ◽  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Northeastern Asia ◽  
Pb Isotope

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 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>

scholarly journals Building Arc Crust: Plutonic to Volcanic Connections in an Extensional Oceanic Arc, the Southern Alisitos Arc, Baja California

2019 ◽  
Vol 60 (6) ◽  
pp. 1195-1228 ◽  
Author(s):  
Rebecca A Morris ◽  
Susan M DeBari ◽  
Cathy Busby ◽  
Sarah Medynski ◽  
Brian R Jicha
Keyword(s):  
Reference Model ◽  
Volcanic Rocks ◽  
Three Dimensional ◽  
Mineral Chemistry ◽  
Major And Trace Elements ◽  
Low Velocity ◽  
Fractionation Process ◽  
Process Step ◽  
Rock Types ◽  
Plutonic Rocks

Abstract The ∼50 km long Rosario segment of the Cretaceous Alisitos oceanic arc terrane provides undeformed three-dimensional exposures of the upper 7 km of an oceanic extensional arc, where crustal generation processes are recorded in both the volcanic and underlying plutonic rocks. These exceptional exposures allow for the study of the physical and chemical links between the rock units and help constrain the differentiation processes active during the growth and evolution of arc crust. This study focuses on the southern third of the Rosario segment, previously referred to as the southern volcano-bounded basin, and its plutonic underpinnings. Upper crustal rocks in the Rosario segment consist of a 3–5 km thick volcanic–volcaniclastic section with hypabyssal intrusions. Plutons intrude these units at various levels along-strike, but at each intrusive contact the transition is complete over a distance of <150 m, where stoped volcanic blocks are present. There is striking compositional overlap in whole-rock and mineral chemistry between the plutonic and volcanic units, suggesting a comagmatic source. Whole-rock geochemistry shows coherent trends in major and trace elements in mafic to intermediate compositions, but less coherent trends above 63 wt % SiO2. Units are predominantly low-K with flat rare earth element patterns, and show large ion lithophile element enrichment and high field strength element depletion. Initial Nd and Pb isotope ratios overlap for all units and imply no cratonic continental involvement. This agrees with low Sr/Y ratios of all rock types, indicative of thin, immature oceanic arc crust. Modeling results show that closed-system fractional crystallization drove crustal differentiation from mafic to intermediate compositions, but open-system processes likely occurred to produce some of the felsic compositions. Differentiation occurred in a two-step fractionation process. Step 1, from basaltic andesite to andesite, fractionated an anhydrous gabbroic cumulate (∼40% crystallization). Step 2, from andesite to rhyolite, fractionated a hydrous amphibole cumulate (∼65% crystallization, total), which is similar to what fluid dynamical models suggest for production of rhyolite (between 50–70% crystallization). Our results can be used as a reference model for differentiation processes relating to the growth of the middle and upper crust within active extensional arc systems. The Rosario segment plutonic rocks may be analogous to the low-velocity zone (Vp = 6·0–6·5 km s–1) imaged within the extensional Izu–Bonin arc. The chemistry of the plutonic and volcanic rocks is most similar to those of volcanic rocks in the Izu–Bonin active rift.

scholarly journals Trace-Element and Pb Isotope Evidence on Extracting Sulfides from Potassic Melts beneath Longmenshan and Molabushan Volcanoes, Wudalianchi, Northeast China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 319 ◽  
Author(s):  
Sergei Rasskazov ◽  
Yi-Min Sun ◽  
Irina Chuvashova ◽  
Tatyana Yasnygina ◽  
Chen Yang ◽  
...  
Keyword(s):  
Trace Element ◽  
Volcanic Rocks ◽  
Volcanic Field ◽  
Lava Flows ◽  
Pb Isotope ◽  
Linear Pattern ◽  
Wide Range ◽  
Mantle Sources ◽  
Isotope Evidence ◽  
Isotope Study

In the Wudalianchi volcanic field, eruptions started with low-Mg potassic lava flows 2.5–2.0 Ma ago and later changed to both low- and moderate-Mg potassic compositions. Volcanic rocks from the Molabushan and Longmenshan volcanoes record an unusually wide range of Pb abundances (from 3.7 ppm to 21 ppm relative to predominant range of 10–15 ppm). To determine the cause of these, we performed a comparative trace-element and Pb isotope study of rocks from these volcanoes and older lava flows. On a uranogenic lead diagram, older low-Mg lavas from lithospheric mantle sources plot on a secondary isochron with a slope corresponding to an age of 1.88 Ga. This contrasts with moderate-Mg volcanic rocks from the Molabushan cone, interpreted to have been derived from a recent convective mantle source, which define a flat linear pattern. Low-Mg rocks from the Molabushan flow have lead isotopic compositions that indicate mixed Gelaqiu and Molabu sources. Relative to rocks from the Molabushan cone, moderate-Mg lavas and slags from the East Longmenshan volcano have modified compositions characterized by Pb, S, and Ni abundances, Ni/Co, Ni/MgO ratios as well as 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, Ce/Pb, Th/Pb, and U/Pb ratios. We infer that the older Wudalianchi magmas were likely derived from a Paleoproterozoic lithospheric fragment, related to the evolved primordial mantle, and that later magmas were generated in the convecting mantle. These were influenced by segregation of small amounts of sulfides.

Glass-bearing felsic nodules from the crystallizing sidewalls of the 1944 Vesuvius magma chamber

2000 ◽  
Vol 64 (3) ◽  
pp. 481-496 ◽  
Author(s):  
P. Fulignati ◽  
P. Marianelli ◽  
A. Sbrana
Keyword(s):  
Magma Chamber ◽  
Melt Inclusions ◽  
Mineral Chemistry ◽  
Glassy Matrix ◽  
Crystal Mush ◽  
Stratigraphic Sequence ◽  
Shallow Magma Chamber ◽  
Mineral Assemblages ◽  
Pressure Crystallization

AbstractIn the 1944 Vesuvius eruption, the shallow magma chamber was disrupted during the highly energetic explosive phases. Abundant cognate xenoliths such as subvolcanic fergusites and cumulates, hornfels, skarns and rare marbles occur in tephra deposits.Mineral chemistry, melt inclusions in minerals and glassy matrix compositions show that fergusites (highly crystalline rocks made of leucite, clinopyroxene, plagioclase, olivine, apatite, oxides and glass) do not correspond to melt compositions but result from combined sidewall accumulation of crystals, formed from K-tephriphonolitic magma resident in the chamber, and in situ crystallization of the intercumulus melt. Very low H2O contents in the intercumulus glass are revealed by FTIR and apatite composition. Whole rock compositions are essentially determined by the bulk mineral assemblages.Glass–bearing fergusites constitute the outer shell of the magma chamber consisting of a highly viscous crystal mush with a melt content in the range 20–50 wt.%. The leucite/(clinopyroxene+olivine) modal ratio, varies with the extraction order of magmas from the chamber, decreasing upwards in the stratigraphic sequence. This reflects a vertical mineralogical zonation of the crystal mush. These data contribute to the interpretation of the subvolcanic low–pressure crystallization processes at the magma chamber sidewalls affecting alkaline potassic magmas.

scholarly journals Mineral chemistry of barium- and titanium-bearing biotites in calc-alkaline volcanic rocks from the Mezitler area (Balikesir-Dursunbey), western Turkey.

2002 ◽  
Vol 36 (6) ◽  
pp. 563-580 ◽  
Author(s):  
Fuat Yavuz ◽  
Ali Haydar Gültekin ◽  
Yüksel Örgün ◽  
Nurgül Çelik ◽  
Muazzez Çelik Karakaya ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Calc Alkaline ◽  
Western Turkey

Polyphase tectonothermal events recorded in metamorphic basement rocks from the northern Altyn Tagh, southeastern Tarim Craton

2020 ◽  
Author(s):  
Zhongmei Wang ◽  
Chunming Han ◽  
Wenjiao Xiao ◽  
Patrick Asamoah Sakyi
Keyword(s):  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Metasedimentary Rocks ◽  
Exposed Rock ◽  
Altyn Tagh ◽  
Argillaceous Rocks ◽  
Southeastern Margin ◽  
Minimum Age ◽  
Tarim Craton

&lt;p&gt;&amp;#160; Paleoproterozoic is a pivotal time for understanding the geochronological framework of the Tarim Craton. Located on the southeastern margin of the Tarim Craton, the northern Altyn Tagh is the main exposed region for Paleoproterozoic magmatic-metamorphic rocks. These rocks are diverse, diachronous and modified by multiple magmatic and/or metamorphic events. In this study, we performed systematic analyses on the amphibolite, felsic gneisses, and metasedimentary rocks in the Aketashitage area, southeastern Tarim Craton, including petrography, mineral chemistry, and whole-rock geochemistry, as well as in-situ zircon U-Pb ages and Hf isotopes, to examine the Paleoproterozoic magmatic-metamorphic events in the northern Altyn Tagh. Geochemically, the amphibolite and felsic gneisses in the Aketashitage area seemingly represent the typical bimodal associations of mafic and acidic volcanic rocks. In addition, the felsic gneisses are characterized by high Sr and low Y contents, with high Sr/Y and La&lt;sub&gt;N&lt;/sub&gt;/Yb&lt;sub&gt;N&lt;/sub&gt; ratios, and indistinctive Eu anomalies, closely resembling high-SiO&lt;sub&gt;2&lt;/sub&gt; adakites derived from subducted basaltic slab-melt. The palimpsest textures and geochemical features of the Aketashitage metasedimentary rocks suggest that their protoliths are argillaceous rocks. The amphibolite has a metamorphic age of 1.96 Ga, and the felsic gneisses yield crystallization ages of 2.54-2.52 Ga. For the metasedimentary rocks, the major age peaks of 2.72 Ga, 2.05 Ga and 1.97 Ga are consistent with the magmatic and/or metamorphic events in the study area. The minimum age peak suggests that the depositional age is no earlier than 1.97 Ga. The geochemical and geochronological evidences documented by the exposed rock associations in the Aketashitage area suggest a subduction-related tectonic setting in the Paleoproterozoic. Our new data combined with the previous studies indicate that the Paleoproterozoic magmatism and metamorphism in the northern Altyn Tagh area are nearly synchronous, and both are likely related to oceanic subduction.&lt;/p&gt;

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