Figure 4. Outcrop of biotite granite located on the summit road between the second and third turns from the summit of Burke Mountain and on the right side of the road if descending. Note the “sheeting structure” or flat joint surface which slopes or dips into the road. This flat break in the rock was probably caused by the release in pressure of the overlying glacial ice when it melted from this region.
Figure 5. East side of parking area, summit of Burke Mountain. Outcrop of granite with many metamorphic rock inclusions (hammer, center of picture, rests on large inclusion). Layering or banding in the inclusions is almost vertical.
Figure 6. Outcrop located about midway down the Bear Den Ski Trail. Alternating metamorphic quartzite and phyllite invaded by lighter colored and speckled biotite granite. Note how the granite cross-cuts the layered or banded metamorphic rocks. This cross-cutting points out the fact that the layering or banding was present prior to the invasion of the granite.
Figure 7. Outcrop located about midway down the Bear Den Ski Trail. Metamorphic quartzite and phyllite (darker color) and invading biotite granite (light speckled appearance). Here the granite has a more or less conformable relationship to the layers or bands in the metamorphic rock. Compare this relationship with the cross-cutting relationship in [Fig. 6]. For scale, the handle of the geologic hammer or pick is about 12 inches long.
Now, what is the relationship of one to the other? That is, where you can see both of these rock types exposed together in one outcrop, can you describe the physical contact of one with the other? For instance, look at [Figure 6], which was taken about midway down the Bear Den Trail, here you see the granite (the white speckled igneous rock which cuts horizontally across the picture) cutting across the distinctly layered or banded metamorphic rocks. The granite is said to have a cross-cutting relationship to the metamorphic rocks. In some outcrops the granite is more or less parallel to the layers of metamorphic rock ([Fig. 7]). Here, the granite is said to have a conformable relationship with the metamorphic rocks. Still another relationship between the granite and the metamorphic rock is seen in [Figure 8]. Here, blocks of metamorphic rocks are inclosed by granite. These inclosed blocks are called inclusions and are pieces of invaded rock which fell into or were encircled by the invading granite.
