In-Situ Trace Elements and Sr Isotopes in Peridotite Xenoliths from Jining:Implications for Lithospheric Mantle Evolution
Wang Ruixue
Liu Yongsheng
Zong Keqing
Hu Zhaochu
Abstract：Further research on the lithospheric mantle beneath western North China craton is significant in order to understand the degree and evolution of its thinning and transformation thoroughly.Mantle peridotite xenoliths in the Cenozoic alkaline basalts from Jining of western North China craton provide important constraints on the nature and evolution of the lithospheric mantle beneath this area.The samples were analyzed by using LA-ICP-MS and LA-MC-ICP-MS to obtain major element, trace element and Sr isotopic compositions.According to the mineral composition, the peridotites were classified into two groups: (1) Clinopyroxene (Cpx)-poor peridotites (Cpx<8%), which might have experienced high-degree partial melting, suggest relict of old and refractory lithospheric mantle under this area.(2) lherzolites (Cpx>13%).They might have experienced low-degree partial melting, representing the fertilized lithospheric mantle.Cpx grains in Type 1 peridotite have relatively low REE contents and show slightly LREE-enriched patterns, while Cpx grains in Type 2 peridotite show both LREE-enriched and slightly LREE-depleted REE patterns.Most Cpx grains show core-rim variations in strong incompatible elements and Sr isotopic compositions.These features indicate that the peridotites could have experienced metamorphism.Variations of (La/Yb)N and Ti/Eu ratios imply multistage metasomatism, which could have been caused by silicate and carbonatite melts/fluids associated with the Paleo-Asian oceanic plate subduction.
Keywords：western North China cratonJiningperdotite xenolithsin situSr isotopePaleo-Asian oceanic plategeochemistry
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：16( 511-526 )