Electron-probe microanalysis of coronas in a

• Main Author: Troctolite From Sulitjelma
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1967
• Subjects: Norway; Sulitjelma; Northern Norway
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.622.3972; http://www.minersoc.org/pages/Archive-MM/Volume_36/36-280-504.pdf

Summary. The results of the electron-probe mieroanatysis ofthe three minerals from orthopyroxene-amphibole spinel coronas between olivine and plagioelase in a troctolite from Sulitjelma, Norway, are presented. They are shown to be incom-patible with a late.magmatic origin for the coronas, but compatible with an origin by diffusion of material in solution in an aqueous medium across the olivine-plagioclase interface. This theory is discussed on a quantitive basis in the light of the mieroanalytical data. EACTION zones, or 'coronas', between olivine and plagioelase are often found in coarse-grained basic or ultrabasic igneous rocks. The reaction zones may consist of a variety of minerals but commonly two zones are present: a zone of orthopyroxene nex ~ to the olivine and a zone of an intergrowth of amphibole and spine] next to the plagioclase (BrSgger, 1934; Shand, 1945). This paper describes an electron-micro-probe study of such zones from a troctolite in the narrow marginal facies of a layered basic igneous pluton at Sulitjelma, northern Norway. The