Gull Island
 

Click on the thumbnail images to view Gull Island Reef perspective images at full size, or use the Location Map at the bottom of the page to navigate to perspective views of other locations.

Figure 3.1 - Shaded relief map of Gull Island Reef. The morphologies are similar to those at Boulder Reef, with the rough relief related by video data to cobble and boulder substrate with less than a meter of local variation. (Greg Kennedy, personal communication) The arcuate shape to the shallowest portions of the reef suggest derivation from a small lobe of ice moving eastward. This contrasts with the southward ice motion suggested by the morphology at Boulder Reef. Erosional or depositional ridges and channels radiate outward to the northeast from the shallowest (3m) portion of the reef, including a pronounced 1 km long and straight ridge at the shallowest part of the ridge. Along the north and east edges of the reef smoother morphologies and bottom sample suggests a modern sand sheet drapes the substrate. Morphologic expression (such as along strike bedding and intraformational boundaries) of the presumed underlying Detroit River Group and Bois Blanc Formation (Fig. 1.1) are not obvious. (See full-size JPEG--284 kb)

Thumbnails

Figure 3.2 - Oblique view looking southeast toward the middle of Lake Michigan. The front of the arcuate ridge and radiating parallel ridges of gravel and boulders are emphasized in this view. Distance across the bottom of image is about 3.4 km. (JPEG 387k)

Location Map
Click on the boxes within the Location Map below to view the mapview and perspective images of those locations.