Engineering Geology Essay

1063 WordsMay 2, 20125 Pages
ENGINEERING GEOLOGY METAMORPHIC ROCKS SUBMITTED TO: SIR IMRAN MEHMOOD SUBMITTED BY: FAISAL ABBAS (57) USMAN JAVED KHAN (67) INAM UR REHMAN (96) QASIM RIAZ (63) RANA SANAULLAH (46) CIVIL ENGINEERING (SEC: B) INTRODUCTION & FORMATION Metamorphism occurs when any previously existing rock, the parent rock, is buried in the earth under layers of other rock. The deeper the rock is buried the hotter it gets, and the higher the pressure becomes. Eventually, rock must adjust to the new conditions, whether it is baked, or squeezed, or both, and in the process becomes a metamorphic rock. [pic] The temperature is going up because the center of the earth is molten, and the closer we get to that heat the hotter it gets. This rise in temperature with depth is called the geothermal gradient. In the phase diagram shown above, temperature increases to the right and pressure and depth increased downward. The arrow is the geothermal gradient. Observe on the far right that the temperature becomes hot enough to melt the rock. TYPES The metamorphic rocks are of following types which have been dominating during the process of transformation ➢ Contact/Thermal metamorphic rocks ➢ Dynamic metamorphic rocks ➢ Thermodynamic metamorphic rocks Contact Metamorphism Contact metamorphism is the name given to the changes that take place when magma is injected into the surrounding solid rock (country rock). The changes that occur are greatest wherever the magma comes into contact with the rock because the temperatures are highest at this boundary and decrease with distance from it. Dynamic Metamorphism The dynamic metamorphism is a structural change in rock that occurs through excretion of pressure. The

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