Name: Course/Section: Date: A Analyze the samples of sedimentary limestone and m

Question

Name: Course/Section: Date: A Analyze the samples of sedimentary limestone and metamorphic marble in Fig. A3 1. These rocks are both composed of the same mineral. What is it? What test could you perform on the rocks to be sure? How is the texture of these two rocks different? 2. limestone marble Figure A3.1 BFigure A3.2 shons three metamorphic rocks that had a mudsione or shale protolith and that display excellent foliation The three specimens represent different metamorphic grades. Highergrade types can also be formed from protoliths other than mudstone, but we are going to think about a progression from mudstone through successively more intense metamorphism. 1. Describe the change in grain size from slate to schist. 2. How does the texture of phyllite differ from that of schis? S. Why do you think that the micas (flat minerals) in these rocks are all parallel, or nearly so, to one another? phyllite schist slate cm A3.2 Analyze the rock sample in Fig. SA. The whise layers in this metamorphic rock-a gneiss-were originally flat, parallel layers that were later folded during metamorphism. Describe a process that could account for how this strong, dense gneiss was folded without breaking during regional metamorphism. (Hint How could you bend a brittle candlestick without breaking it?) D Analyze the foliated metamorphic rock sample in Fig. A3.3 I. What mineral defines the foliation in this rock? Notice that the rock consists mostly of muscovite but also contains scattered garnet crystals. What is the name for this kind of texture?

Explanation / Answer

A 1. The figure is showing limestone (fossiliferous limestone biogenic origin) and marble, both of which contains the mineral calcite (CaCO3). The difference is limestone is a sedimentary rock while the marble is the metamorphic rock formed by the metamorphism of limestone.

We can react it with mild acid and this will produce effervescence which will confirm the presence of calcite (CaCO3).

A 2. The texture is different in both the rock as in the left we have a biogenic rock which contains the shells and other hard parts of organisms (most probably oceanic origin) while on the right we have particle small in size.

B 1. As the extent of metamorphism increases the rock crystals in the metamorphic rocks become more and more coarse grained. Slate is low grade metamorphic rock while schist in medium grade metamorphic rock and hence the size of grain would be more in schist.

B 2. Again using the principle above we can say that Phyllite is a fine-grained metamorphic rock while Schist have more coarse-grained particles. In Phyllite we can see a well developed laminar structure while is schist their is the presence of layers of different minerals and can be split into thin irregularplates.

As per chegg's policy we are adviced to attempt only the first four parts of a questioner, please post the remaing questions as a different questioner. Thanks

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