【作 者】Yangting LIN1, Sen HU1, Bingkui MIAO2, Lin XU3, Yu LIU1, Liewen XIE1,Lu FENG1, and Jing YANG
【摘 要】Grove Mountains (GRV) 020090 is an enriched lherzolitic she rgottite, distinctfrom other lherzol itic shergottites, except RBT 04262/1. Its characteristics include highabundance of plagioclase (24.2 vol% in the nonpoikiliti c area), presence of K-feldspar,common occurrence of baddeleyite, high FeO contents of olivin e (bimodal peaks at Fa33 mol% and Fa 41 mol%) and low-Ca pyroxenes (bimodal peaks at Fs 23.8–31.7 mol%and Fs 25.7–33.9 mol%), and significant LREE enrichm ent of phosphates (500–610 9 CI).The bulk co mposition of GRV 020090 suggests deriva tion from partial melting of anenriched reservoir. However, the REE patterns of the cores of pigeonite oikocrysts and theolivine ch adacrysts are indistinguishable from those of GRV 99027 and other moderatelydepleted lherzolitic shergottites, and reveal a LREE-depleted pattern of the pr imordialparent magma. We propose that the primordial parent magma of GRV 020090 was derivedfrom a moderately depleted Martian upper mantle reservoir, and later the residual melt wascontaminated by oxidized and enriched Martian crustal materials as it ascended up to thesubsurface. GRV 020090 and RBT 04262/1 may have sampled an igneous unit differentfrom other lherzolitic shergottites.