Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications

We present geological, bulk-rock geochemical and Sr–Nd–Hf isotopic data for mafic rocks from the West Philippine Basin (WPB). These mafic rocks comprise pillow basalts characterized by a vesicular structure. The mid-ocean ridge basalt (MORB)-normalized trace element patterns of basalts from the stud...

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Autores principales:	Zhengxin Yin, Weiping Wang, Liang Chen, Zhengyuan Li, Qiang Liu, Anyuan Xie
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	basalt geochemistry isotopes West Philippine Basin Mineralogy QE351-399.2
Acceso en línea:	https://doaj.org/article/cde251e269164758b29abeaff8b1412a
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spelling	oai:doaj.org-article:cde251e269164758b29abeaff8b1412a2021-11-25T18:26:47ZBasalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications10.3390/min111112772075-163Xhttps://doaj.org/article/cde251e269164758b29abeaff8b1412a2021-11-01T00:00:00Zhttps://www.mdpi.com/2075-163X/11/11/1277https://doaj.org/toc/2075-163XWe present geological, bulk-rock geochemical and Sr–Nd–Hf isotopic data for mafic rocks from the West Philippine Basin (WPB). These mafic rocks comprise pillow basalts characterized by a vesicular structure. The mid-ocean ridge basalt (MORB)-normalized trace element patterns of basalts from the study area display depletions in Nb. In addition, the chondrite-normalized lanthanide patterns of basalts from the WPB are characterized by significant depletions in the light lanthanides and nearly flat Eu to Lu segments. The investigated rocks have initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (<sup>87</sup>Sr/<sup>86</sup>Sr(i)) of 0.703339–0.703455 and high ε<sub>Nd</sub>(t) values (8.0 to 8.7). Furthermore, basalts from the WPB have <sup>176</sup>Hf/<sup>177</sup>Hf ratios that range from 0.28318 to 0.28321 and high ε<sub>Hf</sub>(t) from 15.2 to 16.3. Semi-quantitative modeling demonstrates that the parental melts of basalts from the study area were derived by ~20% adiabatic decompression melting of a rising spinel-bearing peridotite source. The Sr–Nd–Hf isotopic compositions of basalts from the WPB indicate that their parental magmas were derived from an upper mantle reservoir possessing the so-called Indian-type isotopic anomaly. Interpretation of the isotopic data suggests that the inferred mantle source was most likely influenced by minor inputs of a sediment melt derived from a downgoing lithospheric slab. Collectively, the petrographic and geochemical characteristics of basalts from the study area are analogous to those of mafic rocks with a back-arc basin (BAB)-like affinity. As such, the petrogenesis of basalts from the WPB can be linked to upwelling of an Indian-type mantle source due to lithospheric slab subduction that was followed by back-arc spreading.Zhengxin YinWeiping WangLiang ChenZhengyuan LiQiang LiuAnyuan XieMDPI AGarticlebasaltgeochemistryisotopesWest Philippine BasinMineralogyQE351-399.2ENMinerals, Vol 11, Iss 1277, p 1277 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	basalt geochemistry isotopes West Philippine Basin Mineralogy QE351-399.2
spellingShingle	basalt geochemistry isotopes West Philippine Basin Mineralogy QE351-399.2 Zhengxin Yin Weiping Wang Liang Chen Zhengyuan Li Qiang Liu Anyuan Xie Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
description	We present geological, bulk-rock geochemical and Sr–Nd–Hf isotopic data for mafic rocks from the West Philippine Basin (WPB). These mafic rocks comprise pillow basalts characterized by a vesicular structure. The mid-ocean ridge basalt (MORB)-normalized trace element patterns of basalts from the study area display depletions in Nb. In addition, the chondrite-normalized lanthanide patterns of basalts from the WPB are characterized by significant depletions in the light lanthanides and nearly flat Eu to Lu segments. The investigated rocks have initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (<sup>87</sup>Sr/<sup>86</sup>Sr(i)) of 0.703339–0.703455 and high ε<sub>Nd</sub>(t) values (8.0 to 8.7). Furthermore, basalts from the WPB have <sup>176</sup>Hf/<sup>177</sup>Hf ratios that range from 0.28318 to 0.28321 and high ε<sub>Hf</sub>(t) from 15.2 to 16.3. Semi-quantitative modeling demonstrates that the parental melts of basalts from the study area were derived by ~20% adiabatic decompression melting of a rising spinel-bearing peridotite source. The Sr–Nd–Hf isotopic compositions of basalts from the WPB indicate that their parental magmas were derived from an upper mantle reservoir possessing the so-called Indian-type isotopic anomaly. Interpretation of the isotopic data suggests that the inferred mantle source was most likely influenced by minor inputs of a sediment melt derived from a downgoing lithospheric slab. Collectively, the petrographic and geochemical characteristics of basalts from the study area are analogous to those of mafic rocks with a back-arc basin (BAB)-like affinity. As such, the petrogenesis of basalts from the WPB can be linked to upwelling of an Indian-type mantle source due to lithospheric slab subduction that was followed by back-arc spreading.
format	article
author	Zhengxin Yin Weiping Wang Liang Chen Zhengyuan Li Qiang Liu Anyuan Xie
author_facet	Zhengxin Yin Weiping Wang Liang Chen Zhengyuan Li Qiang Liu Anyuan Xie
author_sort	Zhengxin Yin
title	Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
title_short	Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
title_full	Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
title_fullStr	Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
title_full_unstemmed	Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications
title_sort	basalt from the extinct spreading center in the west philippine basin: new geochemical results and their petrologic and tectonic implications
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/cde251e269164758b29abeaff8b1412a
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Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic Implications

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