The purpose of this project is to experimentally determine the chemical variability of several granite samples collected from two small islands. The two islands, SwanÕs and Long are part of the Coastal Maine Magmatic Province (Chapman, 1962). These two islands may be part of two plutons that may have interacted sometime in the past. The samples were examined looking for biotite and plagioclase feldspar to compare. The comparisons may tell us something about the formation of the two islands. The Scanning Electron Microscope and the Energy Dispersive X-Ray system were used for this examination. The EDS system delineates chemical compositions using the characteristic x-rays produced by the specimens when the electron beam strikes them.
This specimen is a coarse grained granite with large quartz crystals and lots of potassium feldspar and few mafics. Spectra were collected from the biotites, hornblendes and the plagioclase crystals. Other phases that were present included quartz. The electron micrograph and the elemental map show very distinct hornblende and plagioclase crystals, which have developed together. There is also some large plagioclase crystals on the lower part of the picture