A layer of granite 1 m thick is present in a sequence of sedimentary rocks, parallel to the bedding in the sedimentary rocks (Fig. 3.8). Is it a dike, a sill, or a stock?
Answer to relevant QuestionsRefer to the previous problem. How can one tell whether it is a sill which intruded between rock layers or whether it is a lava flow which was extruded on top of sedimentary rock and then was covered with other sediments?Why was obsidian a much sought after rock which was traded far and wide by the Native Americans? (For example, obsidian from Yellowstone Park was traded as far east as Ohio.)How would one distinguish between an amygdaloidal basalt and a porphyritic basalt?Note the map of major igneous rock bodies along western North America (Fig. 3.15). Name the type of igneous bodies shown, and name the likely dominant rock type present.What causes chemical weathering?
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