The object of my research was to create a series of maps that describe the distribution of minerals and paleokarst in Linwood Mine in an attempt to understand the conditions under which these minerals formed. Linwood Mine is an underground room-and-pillar limestone mine characterized by paleokarst, which is defined as ancient topographic features that resulted from groundwater flow and dissolution of carbonate rock.
With the Geographic Information System ArcView, I created computerized maps, using a digitizing tablet and puck to trace over pre-existing hand-drawn maps that show the location of the dissolution cavities. A database from previous studies of the mine documents a wide variety of information about each cavity, including its size, the minerals it contains, and the geologic feature that controlled its formation. The database was imported from Microsoft Excel and joined to the images in ArcView. Cavities corresponding with specific values for these attributes may be displayed as maps, which then can be overlaid for viewing simultaneously. Viewing maps in combination with one another enables the ArcView user to see how attributes may be related or influence other attributes. Analyses of many different combinations of maps revealed that most minerals,
including calcite, iron sulfides, and barite, are distributed randomly throughout Linwood Mine, suggesting that past conditions favoring mineral formation have been widespread. Sphalerite and chalcopyrite exhibit smaller, more defined ranges. Because of its close association with mineralized cavities, the presence of green clay is believed to play a role in the precipitation of minerals.
Jennifer Carrell, ’99 Portland, OR
Majors: Geology, Environmental Studies, Russian
Sponsor: Paul Garvin