THE FEATURE OF THE REFLECTANCE SPECTRA OF UNEQUIUBRIUM QINGZHEN ENSTATITE CHONDRITE (EH3)

The visible and near-infrared reflectance spectra. of unequilibrium Qingzhen enstatite chondrite (EH3) were measured. It is found that the reflectance spectra are different not only from those of Abee enstatite chondrite (EH4), showing Ni, Fe metal signature, but also from those of EH5 and EL6 enstatite chondrite, showing troilite feature. These unusual reflectance spectra of Qingzhen chondrite may originate from its metal grains which are coated with an accretionary layer of optical thickness. The layer is probably composed of perryite and/or mixture of perryite and sulfide. These metal grains probably have very low oxygen fugacity and are very easy to be oxidized by. air. The cosmochemical mechanism causing different reflectance spectra features of EH3, EH4, EH5 and EL6 enstatite chondrites are discussed.