SPATIAL AND TEMPORAL ANALYSIS OF BLUESTONE QUARRIES IN NEW YORK STATE

Devonian sandstone units occurring in the Catskill magnafacies in southeastern NY have been a source of dimension stone, collectively known as bluestone, for almost 200 years. During that time, the locations of quarries, both geographic and stratigraphic, have changed. To quantify this change, quarry locations were interpreted from airphotos, circa 1968, through a twelve quad, 1,507,632 km2 , area and their locations, elevations, and geologic units digitized. It was determined, at that time, 348 quarries existed in three stratigraphic units ranging in elevation from 1060 to 2400 ft., with an average elevation of 1760 ft. The production of a new series of airphotos, circa 1998, enabled the locations, elevations, and geologic units of the then open quarries to be digitized showing that 752 quarries in four stratigraphic units ranging in elevation from 900 to 2500 ft and averaging 1730 ft., existed the same twelve quad area. Also the areas of 1998 quarrying activity were measured showing that 0.16% of this twelve quad area is affected by quarry activity. The density of quarrying activity in this area increased from 0.468 quarries/km2 in 1968 to 0.742 quarries/km2 in 1998 and the area of maximum density shifted almost 5 km to the northeast. The 1968 quarry point data was compared to the centroids of the 1998 area data to show that of the 346 1968 quarries, only 68 (19.65%) are still visible on the 1998 airphotos. Using the 1998 quarry area data, only 46 (13.29%) of the 1968 quarries fall within 100m of quarry areas identified. In light of proposed scenic by legislation, viewshed analysis was conducted for four potentially impacted quads in the study area. While the number of quarries increased by 58.1% from 1968 to 1998, there was a 2.2% decrease in visibility from the proposed state scenic highways.