scholarly journals Geochemical Characterization of Intraplate Magmatism from Quaternary Alkaline Volcanic Rocks on Jeju Island, South Korea

2021 ◽  
Vol 11 (15) ◽  
pp. 7030
Author(s):  
Cheolhong Kim ◽  
Naing Aung Khant ◽  
Yongmun Jeon ◽  
Heejung Kim ◽  
Chungwan Lim
Keyword(s):  
Fractional Crystallization ◽  
Upper Mantle ◽  
Volcanic Rocks ◽  
Pacific Plate ◽  
Mantle Xenoliths ◽  
Jeju Island ◽  
Eurasian Plate ◽  
Intraplate Magmatism ◽  
The Pacific ◽  
Host Basalt

The major and trace elements of Quaternary alkaline volcanic rocks on Jeju Island were analyzed to determine their origin and formation mechanism. The samples included tephrite, trachybasalts, basaltic trachyandesites, tephriphonolites, trachytes, and mantle xenoliths in the host basalt. Although the samples exhibited diversity in SiO2 contents, the relations of Zr vs. Nb and La vs. Nb indicated that the rocks were formed from the fractional crystallization of a single parent magma with slight continental crustal contamination (r: 0–0.3 by AFC modeling), rather than by the mixing of different magma sources. The volcanic rocks had an enriched-mantle-2-like ocean island basalt signature and the basalt was formed by partial melting of the upper mantle, represented by the xenolith samples of our study. The upper mantle of Jeju was affected by arc magmatism, associated with the subduction of the Pacific Plate beneath the Eurasian Plate. Therefore, we inferred that two separate magmatic events occurred on Jeju Island: one associated with the subduction of the Pacific Plate beneath the Eurasian Plate (represented by xenoliths), and another associated with a divergent setting when intraplate magmatism occurred (represented by the host rocks). With AFC modeling, it can be proposed that the Jeju volcanic rocks were formed by the fractional crystallization of the upper mantle combined with assimilation of the continental crust. The xenoliths in this study had different geochemical patterns from previously reported xenoliths, warranting further investigations.

Ultramafic mantle xenoliths in the Late Cenozoic Volcanic rocks of the Antarctic Peninsula and Jones Mountains, West Antarctica

2021 ◽  
pp. M56-2019-44
Author(s):  
Philip T. Leat ◽  
Aidan J. Ross ◽  
Sally A. Gibson
Keyword(s):  
Antarctic Peninsula ◽  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Incompatible Trace Element ◽  
Mantle Xenoliths ◽  
South Shetland Islands ◽  
West Antarctica ◽  
Gondwana Margin

AbstractAbundant mantle-derived ultramafic xenoliths occur in Cenozoic (7.7-1.5 Ma) mafic alkaline volcanic rocks along the former active margin of West Antarctica, that extends from the northern Antarctic Peninsula to Jones Mountains. The xenoliths are restricted to post-subduction volcanic rocks that were emplaced in fore-arc or back-arc positions relative to the Mesozoic-Cenozoic Antarctic Peninsula volcanic arc. The xenoliths are spinel-bearing, include harzburgites, lherzolites, wehrlites and pyroxenites, and provide the only direct evidence of the composition of the lithospheric mantle underlying most of the margin. The harzburgites may be residues of melt extraction from the upper mantle (in a mid-ocean ridge type setting), that accreted to form oceanic lithosphere, which was then subsequently tectonically emplaced along the active Gondwana margin. An exposed highly-depleted dunite-serpentinite upper mantle complex on Gibbs Island, South Shetland Islands, supports this interpretation. In contrast, pyroxenites, wehrlites and lherzolites reflect percolation of mafic alkaline melts through the lithospheric mantle. Volatile and incompatible trace element compositions imply that these interacting melts were related to the post-subduction magmatism which hosts the xenoliths. The scattered distribution of such magmatism and the history of accretion suggest that the dominant composition of sub-Antarctic Peninsula lithospheric mantle is likely to be harzburgitic.

scholarly journals Redox state of southern Tibetan upper mantle and ultrapotassic magmas

Geology ◽  
2020 ◽  
Vol 48 (7) ◽  
pp. 733-736 ◽  
Author(s):  
Weikai Li ◽  
Zhiming Yang ◽  
Massimo Chiaradia ◽  
Yong Lai ◽  
Chao Yu ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Redox State ◽  
Volcanic Rocks ◽  
Mantle Xenoliths ◽  
Continental Plate ◽  
Cratonic Mantle ◽  
Tectonic Settings ◽  
Mantle Condition ◽  
Typical Range

Abstract The redox state of Earth’s upper mantle in several tectonic settings, such as cratonic mantle, oceanic mantle, and mantle wedges beneath magmatic arcs, has been well documented. In contrast, oxygen fugacity () data of upper mantle under orogens worldwide are rare, and the mechanism responsible for the mantle condition under orogens is not well constrained. In this study, we investigated the of mantle xenoliths derived from the southern Tibetan lithospheric mantle beneath the Himalayan orogen, and that of postcollisional ultrapotassic volcanic rocks hosting the xenoliths. The of mantle xenoliths ranges from ΔFMQ = +0.5 to +1.2 (where ΔFMQ is the deviation of log from the fayalite-magnetite-quartz buffer), indicating that the southern Tibetan lithospheric mantle is more oxidized than cratonic and oceanic mantle, and it falls within the typical range of mantle wedge values. Mineralogical evidence suggests that water-rich fluids and sediment melts liberated from both the subducting Neo-Tethyan oceanic slab and perhaps the Indian continental plate could have oxidized the southern Tibetan lithospheric mantle. The conditions of ultrapotassic magmas show a shift toward more oxidized conditions during ascent (from ΔFMQ = +0.8 to +3.0). Crustal evolution processes (e.g., fractionation) could influence magmatic , and thus the redox state of mantle-derived magma may not simply represent its mantle source.

Cenozoic upper mantle plumes in east Siberia and central Mongolia and subduction of the Pacific plate

2006 ◽  
Vol 409 (1) ◽  
pp. 723-726 ◽  
Author(s):  
Yu. A. Zorin ◽  
E. Kh. Turutanov ◽  
V. M. Kozhevnikov ◽  
S. V. Rasskazov ◽  
A. V. Ivanov
Keyword(s):  
Upper Mantle ◽  
Pacific Plate ◽  
Mantle Plumes ◽  
East Siberia ◽  
Central Mongolia ◽  
The Pacific

The Late Cenozoic Volcanic Groups in the South Daxing'anling, NE China: Geology, Geochemistry, and Chronology

2020 ◽  
pp. SP510-2020-28
Author(s):  
Ni Li ◽  
Yong-Wei Zhao ◽  
Li-Wen Gong ◽  
Jia-Long Wang
Keyword(s):  
Inner Mongolia ◽  
Large Scale ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Mantle Xenoliths ◽  
Late Cenozoic ◽  
The South ◽  
Ne China ◽  
The Pacific ◽  
Eastern Inner Mongolia

AbstractDuring the late Cenozoic, the extensional tectonic setting in northeastern China caused large-scale block uplifts and depressions, and thus a large amount of magma erupted along structural fractures in the eastern Inner Mongolia, NE China. The Abaga, Beilike, Dalinor and Wulanhada (ABDW) volcanic rocks along the Daxing'anling-Taihangshan Gravity Lineament in the southern section of the Daxing'anling are characterized by their extensive distribution, numerous volcanic cones and various eruption types. Each volcanic group has distinctive volcanic landforms and geochemical characteristics. The geochronological data have revealed that the volcanism spanned Miocene to late Pleistocene. The ABDW volcanic rocks contain primary alkaline basalts and subordinate tholeiites. The trace element curve pattern is similar to that of OIB, but completely different from that of MORB, while the LREE are more enriched than HREE. The geochemical features of the volcanic rocks and the entrained mantle xenoliths reveal the broad heterogeneities of the lithospheric mantle and varieties of the volcanic rock evolution in the south Daxing'anling. The Cenozoic volcanism in eastern Inner Mongolia, and even within the east Asian plate, is attributed to the westward subduction and rolling backward of the Pacific slab as well as the trench retreat.

scholarly journals Pemakaian Bracing Pada Bangunan Tahan Gempa dengan Analisis Pushover (The Usage of Bracing on Earthquake Resistant Buildings with Pushover Analysis)

2016 ◽  
Vol 1 (01) ◽  
pp. 84
Author(s):  
Dwi Wahyu Anggraeni ◽  
Erno Widayanto ◽  
Dwi Nurtanto
Keyword(s):  
Collision Energy ◽  
Pushover Analysis ◽  
Pacific Plate ◽  
Earthquake Response ◽  
Eurasian Plate ◽  
High Rise ◽  
Australian Plate ◽  
The Pacific ◽  
Earthquake Resistant ◽  
The Difference

AbstractMost of Indonesia area is an earthquake- prone region. This is caused by the confluence of three major plates world that are subduction. Indo-Australian Plate colliding with the Eurasian plate off the coast of Sumatra, Java and Nusa Tenggara, while the Pacific plate in northern Guinea and North Maluku. In the vicinity of the meeting location this plate collision energy accumulated in the form of earthquake. The quake destroyed much of the multi-storey buildings that do not have adequate strength. Therefore , the higher the building, the greater the effects of the earthquake were received by the building. One way to acquire resistance to earthquake response was to add rigidity to a building. How to obtain the stiffness of a building is to install bracing for high-rise buildings. The purpose of this analysis was conducted to determine usage behavior particularly bracing displacement. The Results of this analysis showed a reduction in horizontal deviation of the building due to the addition of frame bracing. The difference in the percentage of horizontal deviation without bresing building and building using bresing X is 82.519%. While the difference in the percentage of horizontal deviation without order bresing building and building using bresing V is 64.904%.Keywords: pushover analysis , bracing, displacement,earthquake AbstrakSebagian besar wilayah Indonesia merupakan wilayah rawan gempa. Hal ini disebabkan oleh pertemuan tiga lempeng utama dunia yang bersifat subdaksi. Lempeng Indo- Australia bertabrakan dengan lempeng Eurasia di lepas pantai Sumatra, Jawa dan Nusa Tenggara, sedangkan lempeng Pasific di utara Irian dan Maluku Utara. Di sekitar lokasi pertemuan lempeng ini akumulasi energi tabrakan terkumpul sehingga lepas berupa gempa bumi. Gempa banyak menghancurkan bangunan- bangunan bertingkat yang tidak mempunyai kekuatan yang memadai. Oleh karena itu, semakin tinggi bangunan maka semakin besar pula efek gempa yang diterima oleh bangunan tersebut. Salah satu cara untuk memperoleh ketahanan terhadap respon gempa adalah menambah kekakuan pada suatu bangunan. Cara memperoleh kekakuan suatu bangunan adalah dengan memasang pengekang (bracing) untuk bangunan tinggi. Tujuan dari analisa ini dilakukan untuk mengetahui perilaku pemakaian bracing khususnya displacement. Hasil dari analisa ini menunjukkan terjadinya pengurangan simpangan horizontal gedung karena adanya penambahan rangka bracing. Selisih presentase simpangan horizontal gedung tanpa bresing dan gedung dengan menggunakan bresing X adalah 82,519%. Sedangkan selisih presentase simpangan horizontal gedung tanpa rangka bresing dan gedung dengan menggunakan bresing V adalah 64,904%.Kata kunci: analisa pushover , bracing, displacement, gempa

RHEOLOGY OF THE LOWER CRUST AND UPPER MANTLE IN THE ACTIVE BOUNDARY BETWEEN THE PACIFIC PLATE AND BAJA CALIFORNIA MICROPLATE

2017 ◽  
Author(s):  
Vasileios Chatzaras ◽  
◽  
Thomas van der Werf ◽  
Leo M. Kriegsman ◽  
Andreas K. Kronenberg ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Lower Crust ◽  
Baja California ◽  
Pacific Plate ◽  
Crust And Upper Mantle ◽  
The Pacific

The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?

2008 ◽  
Vol 45 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Jaroslav Dostal ◽  
J Duncan Keppie ◽  
B Neil Church ◽  
Peter H Reynolds ◽  
Cheryl R Reid
Keyword(s):  
Volcanic Rocks ◽  
Pacific Plate ◽  
North American Plate ◽  
Volcanic Complex ◽  
Canadian Cordillera ◽  
Continental Flood Basalts ◽  
The North ◽  
South Central ◽  
The Pacific ◽  
Back Arc

The Tertiary (Paleogene and Neogene) geological record in south-central Canadian Cordillera is dominated by the 350–400 km wide, lower Eocene volcanic arc and the overlying Miocene–Recent back-arc lavas that are separated by a hiatus in magmatic activity between 48 and 24 Ma. In the Black Dome area (~240 km north of Vancouver), the Eocene volcanic rocks are mainly continental margin calc-alkaline andesite and dacite, resulting from the melting of a juvenile mafic source at the base of the crust. In contrast, the Miocene volcanic rocks resemble continental flood basalts. Both Eocene and Miocene rocks from the Black Dome volcanic complex have high positive εNd values (+7.2 to +7.4 and +6.4 to +7.6, respectively) and low initial Sr isotopic ratios (0.702 516 – 0.703 528 and 0.703 376 – 0.703 392, respectively) comparable to modern oceanic basalts. The onset of the hiatus in magmatism at 48 Ma coincides with capture of the Kula Plate by the Pacific Plate resulting in a change in convergence direction with the North American Plate from orthogonal to margin-parallel. The margin-parallel motion is inferred to have removed a 50–100 km sliver of the Eocene forearc that formed the boundary between the Pacific and subducted Kula Plate. Reinitiation of arc magmatism at 24 Ma is related to subduction of the Farallon and associated plates and it superimposed back-arc tholeiitic magmatism on top of the Eocene arc.

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