Mineralogical and chemical investigations of a sample from the Seqi olivine deposit, Greenland

Abstract

This report describes the mineralogical characteristics of a sample from the Seqi olivine deposit and presents chemical analyses of the same rock.The Seqi rock is a dunite with a grain size that varies from 0.2 to about 2 mm. The grain boundaries are regular and almost straight (granoblastic texture) indicating crystallization under static conditions. The rock is fresh with little serpentinization. Individual olivine grains are homogeneous with little internal fractures The rock contains 96% olivine, 2% enstatite, 1.5 % chromite and 0.5 % chlorite. Chemical analysis show that the rock contains 49.4% MgO, 0.7% Na2O+K2O and LOI is 0.60 %. Density measurements are in the range 3.27-3.28 g\/cm3, confirming that the rock has a low degree of serpentinization. Some older and open data on the general geology of the Seqi area and analytical data from GEUS, Denmark are also presented.