DETAILED GRAVITY AND MAGNETIC SURVEY ACROSS THE CHIPPEWA CREEK FAULT, NY

The Chippewa Creek fault is located in the St. Lawrence Valley in Northwestern New York. The fault is located midway between Massena, NY and Lake Ontario. The fault is named for the linear northeast oriented Chippewa Creek Valley. Field studies indicate the Chippewa Creek fault is a normal fault with the upthrown side in the southeast.

Fifty-eight magnetic measurements and sixty-five gravity measurements were made along Oak Point Road across the fault at 50-meter intervals to better understand the origin of the fault. Gravity and magnetic surveys are excellent tools for locating faults because faults commonly juxtapose rocks of different densities and intensities of magnetization. Variations in the Earth's gravitational and magnetic fields due to faulting are usually detected from gravity and magnetic measurements.

The gravity and magnetic surveys offer supporting evidence for faulting. The gravity and magnetic traverses indicated gravity and magnetic highs along the traverse in the northwest and gravity and magnetic lows in the southeast. The inflection point of the profiles is taken as the location of the fault. The rocks involved in the fault are Precambrian granite and gneisses. The profiles also revealed many closely spaced gravity and magnetic anomalies probably due to fractures in the rocks.