Island arc and mid-ocean ridge volcanism, modelled by diapirism from linear source regions

1988 ◽  
Vol 88 (1-2) ◽  
pp. 143-152 ◽  
Author(s):  
Ross C. Kerr ◽  
John R. Lister
Keyword(s):  
Island Arc ◽  
Linear Source ◽  
Source Regions ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Protolith Oceanic Island Arc dari Granitoid Tipe M dan I di Karangsambung, Kebumen, Jawa Tengah

2019 ◽  
Vol 20 (4) ◽  
pp. 249
Author(s):  
Chusni Ansori ◽  
Shaban Godang ◽  
Defry Hastria ◽  
Isyqi Isyqi
Keyword(s):  
Field Studies ◽  
Oceanic Island ◽  
Island Arc ◽  
Rock Fragments ◽  
Geochemical Study ◽  
Mid Ocean Ridge ◽  
Granitoid Rocks ◽  
Ocean Ridge ◽  
Mantle Magma ◽  
Carbonatite Magma

Granitoid rocks which found at Luk Ulo melange complex as rock fragments with  pale gray colour and faneritic texture. Petrogenesis and geotectonic of the granitoid is under debate. Some geologists consider as plagiogranite, which is formed from the Mid Ocean-ridge (MOR); or leucogranite which is formed from continental collision, and others argue as arc-related granitoid type.The field studies ware carried out on 5 (five) tracks around Luk Ulo River and 1 (one) track at Lokidang River. The pale grey Karangsambung granitoid is composed of the mainly  K-feldspar (34-55%), plagioclase (10-25%) and quartz (25-35%), and chemically contains SiO2 (61.25 - 66.06%); Al2O3 (13.94 – 14.61%), K2O (2.53 - 4.00%), Na2O (3.42 - 4.10%), CaO (2.32 - 4.76%), Fe2O3 total (5.85 – 8.71%), MgO (0.98 – 1.97%). The granitoid is M- and I-type that were formed at 760o - 800o C with a depth of about 20-30 km, resulting from the differentiation of magma from a fragment origin of the K-enriched oceanic island arc originating from drifting of the IAB fragment. The sample of basalt 17D has a relatively high of Nb/Ta ratio (20), low Rb (<2 ppm), low Ba (17 ppm), and is interpreted as interacting with MORB mantle magma containing rutile-melt;whereas quartz monzonite (17A) has a relatively low of Zr/Sm ratio (3.86), which is indicated to have been contaminated by a carbonatite magma. The spidergram pattern of mantle metagabbro (sample no. 13) similar with the basalt from IAB-Bransfield Strait (Antarctica). Results of a comprehensive geochemical study proposes that the current condition of the Karangsambung zone is part of geotectonic of ACM-Eurasia, that composed of a combination of four rock fragments, i.e. (a) the rocks which sourced from IAB fragments, (b) mantle MORB, (c) continental crust from the origin of ACM-Eurasia, (d) the origin fragment from carbonatite magma.Keyword: Luk Ulo Melange Complex, pale grey granitoid, Island-arc granitoid, M  and I-type granitoid

Mid-ocean ridge and island-arc affinities in ophiolites from Iran: Palaeographic implications

1983 ◽  
Vol 39 (1-2) ◽  
pp. 39-63 ◽  
Author(s):  
Jacqueline Desmons ◽  
Luigi Beccaluva
Keyword(s):  
Island Arc ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Testing of multidimensional tectonomagmatic discrimination diagrams on fresh and altered rocks

2016 ◽  
Vol 67 (2) ◽  
pp. 197-323 ◽  
Author(s):  
M. Abdelaly Rivera-Gómez ◽  
Surendra P. Verma
Keyword(s):  
Case Studies ◽  
Tectonic Setting ◽  
Continental Rift ◽  
Island Arc ◽  
Ocean Island ◽  
Continental Arc ◽  
Mid Ocean Ridge ◽  
Weathered Rocks ◽  
Tectonic Settings ◽  
Ocean Ridge

AbstractWe evaluated 55 multidimensional diagrams proposed during 2004-2013 for the tectonic discrimination of ultrabasic, basic, intermediate, and acid magmas. The Miocene to Recent rock samples for testing the diagrams had not been used for constructing them. Eighteen test studies (2 from ocean island; 2 from ocean island/continental rift; 6 from continental rift; 4 from continental arc; 2 from island arc; 1 from mid-ocean ridge, and 1 from collision) of relatively fresh rocks fully confirmed the satisfactory functioning of these diagrams for all tectonic fields for which they were proposed. Eight additional case studies on hydrothermally altered or moderately to highly weathered rocks were also presented to achieve further understanding of the functioning of these diagrams. For these rocks as well, the diagrams indicated the expected tectonic setting. We also show that for testing or using these diagrams the freely-available geochemistry databases should be used with caution but certainly after ascertaining the correct magma types to select the appropriate diagram sets. The results encourage us to recommend these diagrams for deciphering the tectonic setting of older terranes or areas with complex or transitional tectonic settings.

PETROGENESIS OF GABBRO FROM ARCTIC GAKKEL MID-OCEAN RIDGE

2019 ◽  
Author(s):  
Yung Ping Lee ◽  
◽  
Jonathan E. Snow ◽  
Yongjun Gao
Keyword(s):  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Melt addition to mid-ocean ridge peridotites increases spinel Cr# with no significant effect on recorded oxygen fugacity

2021 ◽  
Vol 566 ◽  
pp. 116951
Author(s):  
Suzanne K. Birner ◽  
Elizabeth Cottrell ◽  
Jessica M. Warren ◽  
Katherine A. Kelley ◽  
Fred A. Davis
Keyword(s):  
Oxygen Fugacity ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

scholarly journals Sunda arc mantle source δ18O value revealed by intracrystal isotope analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Frances M. Deegan ◽  
Martin J. Whitehouse ◽  
Valentin R. Troll ◽  
Harri Geiger ◽  
Heejin Jeon ◽  
...  
Keyword(s):  
Mantle Source ◽  
Secondary Ion Mass Spectrometry ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Sunda Arc ◽  
Mid Ocean Ridge ◽  
Plumbing Systems ◽  
Ocean Ridge ◽  
Secondary Ion ◽  
Magma Plumbing

AbstractMagma plumbing systems underlying subduction zone volcanoes extend from the mantle through the overlying crust and facilitate protracted fractional crystallisation, assimilation, and mixing, which frequently obscures a clear view of mantle source compositions. In order to see through this crustal noise, we present intracrystal Secondary Ion Mass Spectrometry (SIMS) δ18O values in clinopyroxene from Merapi, Kelut, Batur, and Agung volcanoes in the Sunda arc, Indonesia, under which the thickness of the crust decreases from ca. 30 km at Merapi to ≤20 km at Agung. Here we show that mean clinopyroxene δ18O values decrease concomitantly with crustal thickness and that lavas from Agung possess mantle-like He-Sr-Nd-Pb isotope ratios and clinopyroxene mean equilibrium melt δ18O values of 5.7 ‰ (±0.2 1 SD) indistinguishable from the δ18O range for Mid Ocean Ridge Basalt (MORB). The oxygen isotope composition of the mantle underlying the East Sunda Arc is therefore largely unaffected by subduction-driven metasomatism and may thus represent a sediment-poor arc end-member.

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