کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4732426 | 1640442 | 2006 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The neodymium isotopic and geochemical composition of serpentinites from ophiolitic assemblages in the Qilian fold belt, northwest China
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The neodymium isotopic and geochemical composition of serpentinites from ophiolitic assemblages in the Qilian fold belt, northwest China The neodymium isotopic and geochemical composition of serpentinites from ophiolitic assemblages in the Qilian fold belt, northwest China](/preview/png/4732426.png)
چکیده انگلیسی
Serpentinites are a common component of ophiolitic assemblages in the Qilian fold belt. Samples associated with MORB-like basalts in the northern low-grade blueschist belt of the North Qilian terrane have lherzolitic and pyroxenitic compositions, high εNd(T) values of +5.5 to +6.9, and likely represent residues from melting along spreading ridge segments. Despite evidence for incompatible element enrichment by hydrothermal fluids which had interacted with the ocean floor sediment pile, samples at the Ayougou locality retain original isotope Sm-Nd systematics and yield a Silurian age of 422±20 Ma with εNd(T)=+6.8. Serpentinites in the southern high-grade blueschist belt of the North Qilian terrane and from the Lha-Jyi terrane of the South/Central Qilian belt are associated with volcanic arc rocks, and include lherzolitic, harzburgitic and dunitic compositions characterised by low εNd(T) values of +3.8 to â2.2. Harzburgitic samples from these localities display U-shaped REE profiles, and weakly developed negative Nb-anomalies superimposed on incompatible element enrichments, and are interpreted as remnants of oceanic lithosphere metasomatised by slab-derived fluids in a supra-subduction zone environment. Anomalous enrichments in the mobile elements U, Sr and Ba in serpentinites throughout the Qilian belt may be attributed to post-obduction alteration by groundwater.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 28, Issues 2â3, 15 November 2006, Pages 119-132
Journal: Journal of Asian Earth Sciences - Volume 28, Issues 2â3, 15 November 2006, Pages 119-132
نویسندگان
Alan D. Smith, Houng-Yi Yang,