Ion microprobe discovery of archaean and early proterozoic zircon xenocrysts in southwest Sweden
A single zircon grain dated by ion probe with a minimum age of 3432±30 Ma was found in a microgranite dyke, which cuts norite of 916±11 Ma Hakefjorden Complex at Älgön on the Swedish west coast north of Gothenburg. Zircons are a rare accessory mineral in this dyke. They could be classified by morphology as orthocrysts and xenocrysts. Data from four orthocrysts show that the dyke originated between
