4D. Geophysical Reconnaissance in the Mount Independence Area: Larrabee’s Point to Chipman Point

Geophysical Reconnaissance in the Mount Independence Area: Larrabee’s Point to Chipman Point. Patricia Manley, Roger Flood, Todd Hannahs. May 1995.

Sediment bedforms are generated at the sediment water interface by the interaction of bottom water flow and bottom topography. Bedforms can be found in rivers, lakes and oceans. The dynamics of these sediment bedforms have been widely studied (Allen, 1985) such that it is possible to determine the direction and to some extent the magnitude of the bottom currents that formed them. Further information about sedimentation processes can be gleaned from analyzing sediments from these features.

A survey was conducted at the southern end of Lake Champlain; from Larabee’s Point ferry crossing to Chipman Point. This survey was designed to locate cultural artifacts. Since submerged cultural artifacts represent obstructions to bottom water flow, they can be the cause of some sediment bedforms. Erosion and deposition processes which create sediment bedforms, might also have an effect on the management and preservation of submerged cultural resources in Lake Champlain. We utilized side-scan sonar, precision depth recorders, a magnetometer and sediment coring in identifying the orientation and location of all cultural artifacts and sediment bedforms. From our analysis, we inferred the average bottom water flow direction in this study region, discuss the nature and formation of the sediment bedforms, and assess the effects of erosion and deposition on the observed cultural artifacts.