Question

noic arains ehtly md shale Lab #4 M maine too Has alie aplits hoets Lab #4: Metamorphic Rocks or more slowle a. When the isotherms are more closely spaced, is the temperature changing more guickly Circle one. ls me 3. The rate at which the temnerature increases with denth is called the geothermal gradient. bndan b. On the diagram on the previous page there is a vertical line marked A. This line represents about 40 km on the diagram. Calculate the average geothermal gradient for this line. Show your work (no calculations, no credit) egrep light ery J Hint: refer to your pre-lab reading for the geothermal gradient formula. Assume that the line starts at the surface at a temperature of 0 C. Use the isotherms you drew to estimate the temperature at the bottom end of the line. Include units (Ckm) Line A: c. Increasing pressure causes rocks to become more dense as they get metamorphosed. Look at where eclogite forms. Do you expect eclogite to be very dense? Although rare, eclogite is occasionally found at the Earth's surface. How can a dense rock, deep in a subduction zone, appear at the surface? Activity 3: A Comprehensive Review Now that you have seen all three main types of rocks (igneous, sedimentary, metamorphic), think about the characteristics of each group. Imagine you are holding the rock samples in your hand, and you are describing the yisual differences between the following examples. 1. What is the difference between a rock from a mineral? 2. How can you tell a non-foliated metamorphic rock from a plutonic igneous rock (other than dunite)? (hint: think abost composition) 3. How are breccia/conglomerate like a porphyritic igneous rock? How are they different? 4. List two tests you might use to tell a biochemical sedimentary rock from a fine-grained clastic sedimentary rock? 78

Answer 1

1- Rock is formed the group of combined mineral. Simply rock can be made up of homogenous mineral or may be heterogenous mineral. Example limestone is a rock which is made up of mineral Calcite.

2-Non foliated metamorphic rock are formed around magma chamber where temperature is high and pressure is low and also they show no banding. Mainly they identified by mineral composition like sillimanite, kyanite etc and rock like marble are classified by the CaCo3

3- Porphyritic is a texturd in igneous rock in which large crystal masses are embedded in finer grain (ground mass). Same as in the conglomerate /breccia they are made up of Angular or rounded fragments and the spaces between these fragments are filled with matrix or cement of finer particles.

The main difference is they are of sedimentary origin.

4- Formation of coal

Chert

Diatomite