31. On the north part of the island, there is a concentration of gabbro and diabase sills. 32. Dikes can vary in texture and their composition can range from diabase or basaltic to metamorphic segregations. 33. The diabase sill formed at roughly 2-3 kilometers beneath the surface ( Sevon 1999 ). 34. The hard diabase intrusions were more resistant to the ice and survived as a network of ridges. 35. This diabase cap is the erosional remnant of a sill that once extended over the entire area. 36. The more resistant diabase dikes remained, while the softer shales were bulldozed away by the glaciers. 37. Pigeon Point is the most eastern part of Minnesota; it is a diabase sill about thick. 38. This includes the Nipissing diabase and Temagami greenstone belt, which hosts a variety of mineral deposits. 39. The basalt cliffs are the margin of a diabase Period by the intrusion of molten magma upward into sandstone. 40. This magma cooled into the diabase dykes seen in the cliffs of Western Brook Pond and Ten Mile Pond.
