Multiple mantle sources of the Early Permian Panjal Traps, Kashmir, India

J.g  Shellnutt*, Ghulam M. Bhat, Kuo Lung Wang, Meng-Wan Yeh, Michael E. Brookfield, Bor Ming Jahn

*此作品的通信作者

    研究成果: 雜誌貢獻期刊論文同行評審

    22 引文 斯高帕斯(Scopus)

    摘要

    The Early Permian Panjal Traps of northern India are the volcanic remnants of continental rifting that led to the formation of the Neotethys Ocean and the ribbon-like continent Cimmeria. The Traps are one of at least five major mafic eruptions of flood basalts during the Late Palaeozoic however their origin and petrogenesis are poorly constrained. Basalts from the Kashmir Valley were collected and analyzed for chemical and isotopic (Sr, Nd) compositions in order to characterize their mantle source and evaluate the petrogenetic processes related to opening of the Neotethys Ocean. Samples collected from the eastern side (Guryal Ravine, Pahalgam, PJ3) of the Kashmir Valley are chemically similar to mildly alkaline to tholeiitic, within-plate flood basalts. The TiO2 contents (TiO2 = 0.8 to 3.1 wt.%), La/YbN values (La/YbN=1.8 to 6.1) and εNd(t) values (εNd(t)=-5.3 to +1.3) along with partial melt modeling indicates that the basalts were likely derived from a spinel peridotite source. In contrast, samples collected from the western side (PJ4) of the Kashmir Valley (Buta Pathri) are more primitive in composition and show evidence for clinopyroxene fractionation. The basalts from the western side of the Kashmir Valley have higher Mg# (Mg#=60 to 78) values and εNd(t) values (εNd(t)=+0.3 to+4.3) suggesting they were derived by slightly higher amounts of partial melting and from a more depleted spinel peridotite source. The changing bulk composition of the basalts from 'enriched OIB-like' on the eastern side to 'depleted MORB-like' compositions on the western side is likely due to the changing nature of the Panjal rift from a nascent continental setting to one transitioning to a mature ocean basin. In comparison to Pangaean and post-Pangaean flood basalt provinces, the Panjal Traps are more chemically similar to the flood basalts from the post-Pangaean provinces that are associated with plate separation.

    原文英語
    頁(從 - 到)589-619
    頁數31
    期刊American Journal of Science
    315
    發行號7
    DOIs
    出版狀態已發佈 - 2015 一月 1

    ASJC Scopus subject areas

    • 地球與行星科學(全部)

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