Question

Part II Questions 1. Analyze the rock sample in figure 5. The parent rock for this comerherock hade Layers that were folded during metamorphin Describes process that could account for how this rigid gneiss was folded without breaking during regionalnomorphism. Het How could you benda candlestick without breaking in 2. Analyze the metamorphic rock sample pictured in figure it using the analysis and classification chart at the end of this lab a. What are the rock's texturel features Here Gatis b. What are the rock's mineralogical composition and other distinctive features c. What is the metamorphic rock name? d. What was the parent rock? e. What is the rock used for? Non-foliated to What happens if the protolith Conssofony Sandstone or premesting The rockshorn metamorphic rock that does not per ottega 3. Analyze the metamorphic rock sample pictured in figure 6 using the analysis and classification chart at the end of this lab. c. What are the rock's textural features? b. What are the rock's mineralogical composition and other distinctive features? c. What is the metamorphic rock name? d. What was the parent rock? e. What is the rock used for? (Hour Marke with Perphyrblastic texture- large crystals called porphyroblasts, set in a finer grained ground mass t Figure 1: Schist with repor

the rocks used for image 5 is a Gneiss with folds. figure 6 is Marble with graphite. figure 11 is Schist with garnet prophyoblasts.

Answer 1

1. Such rigid gneisses can be folded ant higher temperatures and pressures, where the behave in a more ductile manner, like a clay. On cooling, they form the rigid gneisses we see in the figure.

2. a)The rock appears to be more or less granoblastic i.e. recrystallized by heating. It shows no foliations.

b) The rock is made of calcite and graphite.

c) The metamorphic name would be granoblastic marble with graphite to indicate its texture as well as composition.

d) The parent rock was a limestone with organic matter. The limestone recrystaillised to form the marble, while the organic matter formed graphite.

e) Marbles are often used as face stones on the walls and in the floorings of buildings. They are also used for artistic sculptures.

3. a)The rock is said to have schistose texture, with is a metamorphic texture with foliations or minerals arranged parallel to one another. Among these foliations, garnet has grown, and hence the term porphyroblast is used.

b) Individual schistose minerals cannot be identified from the photograph, but they appear to be a mica. Garnet is also present.

c) The metamorphic name for such a rock if composed of mica is mica schist with porphyroblastic garnet.

d) The parent rock was a sedimentary rock rich in aluminous sediment like a shale.

e) This rock can be used to extract garnets, which have a variety of use such as abrasives and gemstones.