Petrogenetic evolution of Lichi volcanics from Arunachal Himalaya, Northeast India: Insights from geochemical modelling,Geological Journal

当前位置： X-MOL 学术 › Geolog. J. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Petrogenetic evolution of Lichi volcanics from Arunachal Himalaya, Northeast India: Insights from geochemical modelling
Geological Journal ( IF 1.4 ) Pub Date : 2022-08-02 , DOI: 10.1002/gj.4563
Neeta Moni Sharma ₁ , Purbajyoti Phukon ₂ , Pramathesh Bhattacharyya ₁

Affiliation

The Lichi volcanic rocks crop out along the Main Boundary Thrust (MBT) of the Arunachal Himalaya, northeast India are comprised primarily of sub-alkaline basalt (SiO₂ ranges from 48.66 to 50.62 wt%), with minor trachy-andesite (SiO₂ ranges from 57% to 61.42 wt%). The distribution of incompatible trace elements, low concentrations of large-ion lithophile elements, and REE behaviour suggests an enriched nature of the studied rocks and limited influence of the crustal contamination during their evolution. Linear distribution trends of major oxide, consistent patterns of trace elements, and REEs on primitive mantle- and chondrite-normalized diagrams suggest the cogenetic nature of mafic basaltic rocks and intermediate trachy-andesite. The variation in Ti/Y (256.00–469.95) and Zr/Y (7.65–36.96) ratios indicates that garnet was present in the source. The well-defined geochemical trends on variation diagram and the sub-parallel trends on the chondrite-normalized REE patterns suggest that fractional crystallization processes have played a major role in the evolution of parental magma. Petrogenetic modelling implies that the sub-alkaline basalts and intermediate rocks were derived from low-degree partial melting (1%–5%) of a garnet bearing peridotite source. The melt further evolved by fractional crystallization. We conclude that the geochemical attributes of the Lichi volcanics of the Arunachal Himalaya imply their emplacement in a continental extensional regime and possibly resulted from the Cretaceous Kerguelen plume activities.

中文翻译：

印度东北部阿鲁纳恰尔喜马拉雅山荔枝火山的岩石成因演化：来自地球化学模拟的见解

印度东北部阿鲁纳恰尔喜马拉雅山脉主边界逆冲断层 (MBT) 沿线出露的荔枝火山岩主要由亚碱性玄武岩 (SiO ₂含量在 48.66 至 50.62 wt% 之间) 和少量粗面安山岩 (SiO ₂范围从 57% 到 61.42 wt%)。不相容微量元素的分布、低浓度的大离子亲石元素和稀土元素行为表明所研究的岩石具有丰富的性质，并且在其演化过程中地壳污染的影响有限。主要氧化物的线性分布趋势、微量元素的一致模式以及原始地幔和球粒陨石归一化图上的 REE 表明基性玄武岩和中间粗面安山岩的共生性质。Ti/Y (256.00–469.95) 和 Zr/Y (7.65–36.96) 比率的变化表明石榴石存在于源中。变化图上明确的地球化学趋势和球粒陨石归一化稀土元素模式的次平行趋势表明，分步结晶过程在母体岩浆的演化中发挥了重要作用。岩石成因模型表明，亚碱性玄武岩和中间岩来源于含石榴石橄榄岩源的低度部分熔融（1%–5%）。通过分级结晶进一步形成熔体。我们的结论是，阿鲁纳恰尔喜马拉雅山荔枝火山的地球化学属性表明它们位于大陆伸展区域，并且可能是白垩纪凯尔盖朗火山喷发活动的结果。岩石成因模型表明，亚碱性玄武岩和中间岩来源于含石榴石橄榄岩源的低度部分熔融（1%–5%）。通过分级结晶进一步形成熔体。我们的结论是，阿鲁纳恰尔喜马拉雅山荔枝火山的地球化学属性表明它们位于大陆伸展区域，并且可能是白垩纪凯尔盖朗火山喷发活动的结果。岩石成因模型表明，亚碱性玄武岩和中间岩来源于含石榴石橄榄岩源的低度部分熔融（1%–5%）。通过分级结晶进一步形成熔体。我们的结论是，阿鲁纳恰尔喜马拉雅山荔枝火山的地球化学属性表明它们位于大陆伸展区域，并且可能是白垩纪凯尔盖朗火山喷发活动的结果。

更新日期：2022-08-02

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11