Upper mantle scale enrichment of Cenozoic intraplate magmatism in Northeast Asia: He-Sr-Nd-Pb-O isotope geochemistry of the basalts around the Korean peninsula

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research Pub Date : 2024-10-14 DOI:10.1016/j.gr.2024.09.016

Donghwan Kim , Hyunwoo Lee , Mi Jung Lee , Changkun Park , Andrea Luca Rizzo

{"title":"Upper mantle scale enrichment of Cenozoic intraplate magmatism in Northeast Asia: He-Sr-Nd-Pb-O isotope geochemistry of the basalts around the Korean peninsula","authors":"Donghwan Kim , Hyunwoo Lee , Mi Jung Lee , Changkun Park , Andrea Luca Rizzo","doi":"10.1016/j.gr.2024.09.016","DOIUrl":null,"url":null,"abstract":"<div><div>The Earth’s mantle is considered to be geochemically heterogeneous, which is reflected by the diverse compositions of oceanic island basalts (OIB). The mantle enrichment resulting in this is primarily attributed to the influx of recycled crustal materials into the mantle through subduction. Additionally, the sub-continental lithospheric mantle (SCLM) complicates the elucidation of mantle heterogeneity. From this perspective, Northeast Asia, where the Pacific stagnant slab in the mantle transition zone and the SCLM distribution are presented, is the suitable site for examining the upper mantle scale enrichment. Here we report He-Sr-Nd-Pb-O isotope compositions of Cenozoic basalts found around the Korean Peninsula to illustrate the source lithology and components that caused mantle heterogeneity. Our measured helium isotope ratios ranging from 5.7 to 7.3 Ra (3He/4He ratio of air, Ra = 1.39 x 10-6) are mostly within the SCLM range (6.1 ± 0.9 Ra) but lower than the mid-ocean ridge basalt range (MORB; 8 ± 1 Ra). The Sr-Nd-Pb isotope compositions of the basalts generally display a mixture of depleted MORB mantle (DMM), enriched mantle 1 (EM1), and enriched mantle 2 (EM2) components. In addition, the basalts have δ18Oolivine (vs. V-SMOW) values ranging from 4.7 to 5.7 ‰ that deviate from the DMM range (δ18Oolivine = 5.1 ± 0.2 ‰). Our isotopic analysis results highlight the role of a pyroxenite source in the metasomatized SCLM in the genesis of basalts, and the low 3He/4He ratios of the basalts indicates a significant contribution of SCLM. Moreover, the delaminated cratonic SCLM and asthenosphere-lithosphere interaction are scenarios for the low 3He/4He ratios. Therefore, we propose that mixing of DMM (high 3He/4He ratio; 7 to 9 Ra) and the metasomatized SCLM (low 3He/4He ratio; 5 to 7 Ra) allowed enrichment within the upper mantle scale for the Cenozoic intraplate magmatism in Northeast Asia.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"137 ","pages":"Pages 349-364"},"PeriodicalIF":7.2000,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gondwana Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1342937X24002879","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

The Earth’s mantle is considered to be geochemically heterogeneous, which is reflected by the diverse compositions of oceanic island basalts (OIB). The mantle enrichment resulting in this is primarily attributed to the influx of recycled crustal materials into the mantle through subduction. Additionally, the sub-continental lithospheric mantle (SCLM) complicates the elucidation of mantle heterogeneity. From this perspective, Northeast Asia, where the Pacific stagnant slab in the mantle transition zone and the SCLM distribution are presented, is the suitable site for examining the upper mantle scale enrichment. Here we report He-Sr-Nd-Pb-O isotope compositions of Cenozoic basalts found around the Korean Peninsula to illustrate the source lithology and components that caused mantle heterogeneity. Our measured helium isotope ratios ranging from 5.7 to 7.3 R_a (³He/⁴He ratio of air, R_a = 1.39 x 10^-6) are mostly within the SCLM range (6.1 ± 0.9 R_a) but lower than the mid-ocean ridge basalt range (MORB; 8 ± 1 R_a). The Sr-Nd-Pb isotope compositions of the basalts generally display a mixture of depleted MORB mantle (DMM), enriched mantle 1 (EM1), and enriched mantle 2 (EM2) components. In addition, the basalts have δ¹⁸O_olivine (vs. V-SMOW) values ranging from 4.7 to 5.7 ‰ that deviate from the DMM range (δ¹⁸O_olivine = 5.1 ± 0.2 ‰). Our isotopic analysis results highlight the role of a pyroxenite source in the metasomatized SCLM in the genesis of basalts, and the low ³He/⁴He ratios of the basalts indicates a significant contribution of SCLM. Moreover, the delaminated cratonic SCLM and asthenosphere-lithosphere interaction are scenarios for the low ³He/⁴He ratios. Therefore, we propose that mixing of DMM (high ³He/⁴He ratio; 7 to 9 R_a) and the metasomatized SCLM (low ³He/⁴He ratio; 5 to 7 R_a) allowed enrichment within the upper mantle scale for the Cenozoic intraplate magmatism in Northeast Asia.

Abstract Image

查看原文本刊更多论文

东北亚新生代板内岩浆活动的上地幔尺度富集：朝鲜半岛周围玄武岩的 He-Sr-Nd-Pb-O 同位素地球化学研究

地球的地幔被认为是地球化学异质的，这反映在大洋岛屿玄武岩（OIB）的不同成分上。造成这种情况的地幔富集主要归因于通过俯冲作用将回收的地壳物质涌入地幔。此外，次大陆岩石圈地幔（SCLM）也使地幔异质性的阐释变得更加复杂。从这个角度来看，地幔过渡带太平洋停滞板和SCLM分布的东北亚是研究上地幔尺度富集的合适地点。在此，我们报告了在朝鲜半岛周围发现的新生代玄武岩的 He-Sr-Nd-Pb-O 同位素组成，以说明造成地幔异质性的源岩性和成分。我们测量到的氦同位素比值从5.7到7.3 Ra（空气的3He/4He比值，Ra = 1.39 x 10-6）不等，大部分在SCLM范围内（6.1 ± 0.9 Ra），但低于洋中脊玄武岩范围（MORB；8 ± 1 Ra）。玄武岩的 Sr-Nd-Pb 同位素成分一般显示出贫化 MORB 地幔（DMM）、富集地幔 1（EM1）和富集地幔 2（EM2）成分的混合物。此外，玄武岩的δ18Oolivine（vs. V-SMOW）值在 4.7 至 5.7 ‰之间，偏离了 DMM 的范围（δ18Oolivine = 5.1 ± 0.2 ‰）。我们的同位素分析结果表明，在玄武岩的成因过程中，变质SCLM中的辉绿岩源起着重要作用，玄武岩的低3He/4He比值表明SCLM起了重要作用。此外，板块状SCLM的分层和岩石圈与星体层的相互作用也是3He/4He比值低的原因。因此，我们认为，DMM（高3He/4He比值；7-9 Ra）和变质SCLM（低3He/4He比值；5-7 Ra）的混合使得东北亚新生代板内岩浆活动在上地幔尺度内富集。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Gondwana Research 地学-地球科学综合

CiteScore

12.90

自引率

6.60%

发文量

298

审稿时长

65 days

期刊介绍： Gondwana Research (GR) is an International Journal aimed to promote high quality research publications on all topics related to solid Earth, particularly with reference to the origin and evolution of continents, continental assemblies and their resources. GR is an "all earth science" journal with no restrictions on geological time, terrane or theme and covers a wide spectrum of topics in geosciences such as geology, geomorphology, palaeontology, structure, petrology, geochemistry, stable isotopes, geochronology, economic geology, exploration geology, engineering geology, geophysics, and environmental geology among other themes, and provides an appropriate forum to integrate studies from different disciplines and different terrains. In addition to regular articles and thematic issues, the journal invites high profile state-of-the-art reviews on thrust area topics for its column, ''GR FOCUS''. Focus articles include short biographies and photographs of the authors. Short articles (within ten printed pages) for rapid publication reporting important discoveries or innovative models of global interest will be considered under the category ''GR LETTERS''.