Changes in chemical composition of peridotite olivine crystals as a result of xenolith–host rock interaction (Jeziorna, Lower Silesia, SW Poland)

Abstract Petrological observations and major elements analyses in olivine crystals in small xenoliths (>1.5 cm in diameter) from the Jeziorna locality, SW Poland, are presented. The olivines show very large variations in the composition of Mg, Fe, Ca and Ni, which suggests the influence of many possible factors, such as (1) regional variability of the samples; (2) changes in temperature during movement and storage of Cenozoic magmas; (3) weathering; and (4) the interaction of basaltic magma with xenoliths in the mantle or during magma ascent. The latter processes are the final changes recorded in the olivine composition. This study contributes to our understanding of which of the changes in chemical composition can be attributed to these final changes, whether they occur only at the xenolith–host rock contact, or whether they also change the olivine composition inside the xenolith.