南极GRV 98003和其它3个铁陨石的化学组成及分类

用仪器中子活化测定了从南极回收的GRV98003铁陨石和乌珠穆沁铁陨石Cr,Co,Ni,Cu,Ga,Ge,As,Sb,W,Re,Ir,Pt及Au的浓度。根据化学组成,重新对这两个未分群的铁陨石进行了分类工作,其中将GRV98003铁陨石划分为IAB群,乌珠穆沁铁陨石划分为与IAB群相关的单独铁陨石。GRV98003铁陨石的元素丰度模式、元素对相关性(如NiAu,CoAu,AsAu,WAu,CuAu,SbAu)等与NWA468铁陨石(IAB)相似,但前者具有明显的难熔亲铁元素(Re,Ir)和中等挥发性元素(Ga,Ge)的贫化。此外,本文还对南丹铁陨石(IIICD)和邕宁铁陨石(IA)的化学群重新进行了讨论,提出将前者划分为IAB复合群的主群,而将后者划分为与IAB复合群相关的单独铁陨石的新观点。

CHEMICAL COMPOSITIONS AND CLASSIFICATION OF GROVE MOUNTAINS (GRV) 98003 AND OTHER THREE IRON METEORITES

Concentrations of Cr, Co, Ni, Cu, Ga, Ge, As, Sb, W, Re, Ir, Pt and Au of GRV 98003, from Antactica, and Ujimqin iron meteorites have been measured by instrumental neutron activation analysis. According to bulk chemistry, the ungrouped GRV 98003 is classified into IAB group, and the ungrouped Ujimqin as a unique iron of IAB iron meteorite complex. The elemental abundance pattern and correlation of elements (e.g. Ni Au, Co Au, As Au, W Au, Cu Au, Sb Au) of GRV 98003 are similar with those of NAW 468 (IAB), but significantly depleted in refractory siderophile elements (Re, It) and moderate volatile elements (Ga, Ge) relative to the latter. Furthermore, the Nantan (IIICD) and Yongning (IA) meteorites are re classified as a member of IAB main group (MG) and a unique iron meteorite related to IAB iron meteorite complex, respectively.