The distribution of trace elements during strong fractionation of basic magma—a further study of the Skaergaard intrusion, East Greenland

摘要: Abstract A number of trace elements have been determined spectrographically in the rocks and minerals Skaergaard intrusion, East Greenland. The original basic magma from which varied complex were developed is shown to had a normal element composition. sorting out into various mineral series produced by strong fractional crystallization traced detail means analyses separated minerals. Certain (Cr, Ni) are be strongly concentrated early so that later fractions little or none them; other (P, V, Cu, Sc, Mn, S) reach maximum values middle, late middle stages represented certain olivine-free gabbros ferrogabbros; (Li, Zr, Y, La, Ba, Rb) tend remain residual liquid during fractionation thus abundant latest granite fraction. Still (Co, Sr, Ga, Mo) show only small changes amount throughout series. Of these Co more stages, Sr Ga Mo but not stages. distribution considered relation varying composition processes an attempt made discuss compositions terms crystal chemical concepts. sequence differentiation gabbros, through ferrogabbros, common trend at high levels crust, observed therefore regarded as having wide geochemical significance. intermediate differentiates significantly different diorites reported workers suggests some origin than magma. On hand many granites resembles fraction intrusion.