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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MDPI AG
2021-11-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/11/11/1277 |
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| 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 |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-03-10T05:15:08Z |
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| id | doaj.art-cde251e269164758b29abeaff8b1412a |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T05:15:08Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-cde251e269164758b29abeaff8b1412a2023-11-23T00:32:57ZengMDPI AGMinerals2075-163X2021-11-011111127710.3390/min11111277Basalt from the Extinct Spreading Center in the West Philippine Basin: New Geochemical Results and Their Petrologic and Tectonic ImplicationsZhengxin Yin0Weiping Wang1Liang Chen2Zhengyuan Li3Qiang Liu4Anyuan Xie5South China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaSouth China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaSouth China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaSouth China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaSouth China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaSouth China Sea Marine Survey and Technology Center, State Oceanic Administration, Guangzhou 510300, ChinaWe 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.https://www.mdpi.com/2075-163X/11/11/1277basaltgeochemistryisotopesWest Philippine Basin |
| spellingShingle | 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 Minerals basalt geochemistry isotopes West Philippine Basin |
| title | 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_short | 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 |
| topic | basalt geochemistry isotopes West Philippine Basin |
| url | https://www.mdpi.com/2075-163X/11/11/1277 |
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