Author Information

Jennifer Fruzzetti


The physico-chemical mechanisms by which rock-forming minerals dissolve in natural fluids are controlled by a number of environmental factors. In this study, we investigate dissolution mechanisms by observing how the nanometer-scale surface topography of calcite is affected by the acidity of etching solutions. Here we report atomic force microscope (AFM) observations of calcite crystal surfaces both before and after chemical etching for 10 seconds in 0.01%, 0.1%, and 1.0% HCl solutions. AFM observations show that unetched, freshly-cleaved calcite {10ī4} crystal surfaces are characterized by flat layers separated by steps oriented parallel to calcite cleavage planes. Calcite {10ī4} crystal surfaces etched in 0.01% HCl are characterized by relatively flat surfaces with deep, well-defined V-shaped (pointed bottom) etch pits. Calcite {10ī4} crystal surfaces etched in 0.1% HCl are characterized by more irregular surfaces, with poorly-defined flat-bottom etch pits. Calcite {10ī4} crystal surfaces etched in 1.0% HCl are characterized by a highly irregular surfaces with a high density of poorlydefined, round-bottom etch pits. The findings from this study are consistent with previously published observations that indicate fluid acidity strongly controls the resultant surface topography of etched calcite. Agreement between the nanometerscale observations made here and those from previous studies provides greater confidence that the new AFM on the campus of Bridgewater State University is fully calibrated and can accurately resolve nanometer-scale topographic features on the surfaces of natural materials.

Note on the Author

Jennifer Fruzzetti graduated from BSU in May 2012 with a Bachelor of Science degree in Earth Sciences and a concentration in Environmental Geosciences. This research was conducted during the spring 2012 semester with her advisor Dr. Stephen E. Kaczmarek and was funded by the ATP Semester Grant Program. Her research was presented at the spring 2012 Undergraduate Research Symposium.

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