PACROFI VI - Electronic Program


A New Oil Immersion Vessel For Optical Spindle Stage Examination Of Fluid And Solid Inclusions

Alan J Anderson

Department of Geology, St. Francis Xavier University, P.O. Box 5000, Antigonish, Nova Scotia, Canada, B2G 2W5


A new oil immersion vessel has been developed for petrographic analysis of fluid inclusions with a spindle stage. With this vessel, immersion liquid is retained during rotation of the spindle with an oil-seal-shaft. The shaft projects through a wall in the vessel and is used to rotate a circular, disc-shaped magnet about a horizontal axis. A mineral grain or polished wafer may be attached to the end of a metal stub which is held within the vessel by the circular magnet. A fluid inclusion can be positioned along the horizontal axis of rotation by movement of the stub across the surface of the magnet with a centering screw. Positioning along the vertical axis of rotation is achieved by translating the immersion vessel in a direction parallel to the horizontal rotation axis.

This modified oil immersion vessel has several advantages relative to the prototype described by Anderson and Bodnar (American Mineralogist, 1993). These are: (1) it is much easier to change and position samples, (2) it can be used with a wider range of refractive index oils, (3) it is simpler and more durable, (4) it is less expensive because a goniometer head is not needed for sample positioning, and (5) the number of rotations about the horizontal axis is unlimited.

The design and operation of the modified spindle stage will be described. A microscope with an attached video camera and monitor will be available for demonstration.