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(Solved): 1(a) Identify the rock's mafic colour index (MCI) as shown in the top of figure 5.5.1(b) The dark co ...
1(b) The dark coloured minerals in the sample are most likely….
1(c) The white minerals are most likely….
1(d) Describe the texture of the rock by using figure 5.4.
1(e) Determine the name of the rock, using the flowchart in figure 5.4 and the expanded classification chart in figure 5.5.
\r\nIGNEOUS ROCKS CLASSIFICATION 1. Mafic Color Index (MCl) Estimate the rock's percent of mafic (green, dark gray, and black) mineral crystals. You can also use visual estimators in GeoTools 1 and 2. 2. Minerals Identify minerals in the rock, if possible, and the percent of each one. You can use visual estimators in GeoTools 1 and 2. Skip this step if the rock is glassy or aphanitic. Fesic Intermediate Mafic Ultramafic Felsic Intermediate 15 Intermediate Mafic Ultramafic (> 85\\% mafic crystals) \\( { }^{1} \\) Phenocrysts are crystals conspicuously larger than the finer grained groundmass (main mass, matrix) of the rock. FIGURE 5.5 Igneous Rock Classification Chart. Obtain data about the rock in Steps 1-3, then use that data to select the name of the rock (Step 4). Also refer to FIGURE 5.4 and the examples of classified igneous rocks in FIGURES 5.8-5.14. Igneous Rocks and Processes 137