The stages From the rock cycle
The rock cycle is a basic concept in geology that describes the time-consuming transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each of the types of rocks is altered or destroyed when it is forced out of its equilibrium conditions. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and are forced to change as they encounter new environments. The rock cycle is an illustration that explains how the three rock types are related to each other, and how processes change from one type to another over time.
Heat and Pressure Rocks are created and destroyed in a cycle known as the rock cycle. Over time rocks change from one type to another. One component of the rock cycle is metamorphism, which is a process of changing the mineralogy, texture and chemical composition of preexisting rocks into Metamorphic Rocks by heat, pressure and chemical processes. Temperatures increase the further rocks descend into Earth's crust. 100-200km below Earth's surface the temperatures are hot enough to melt most rocks, and turn them in to molten magma.The resulting type of rock is known as a metamorphic rock. The process of metamorphism typically occurs beneath the Earth’s surface, where temperatures are high enough to modify rocks while in a solid state, and pressure from other rocks causes the rock to change. Cooling Igneous rocks are the result of cooling and crystallizing magma. Igneous crystals are formed when freely moving atoms in melted rock become arranged in orderly patterns as they cool. As melted rock cools, the heat energy that allows atoms to move past one another decreases, and the natural attraction between atoms causes them to stick together with similar atoms in a crystalline structure. This process takes a long time to grow big enough to be seen. igneous rocks can form on Earth's surface and underneath it forming a different type of igneous rock. The cooling process is different in these separate locations as on Earth's surface lava emitted from a volcano cools at a much more rapid rate due to the cooler temperatures surrounding it. Underneath Earth's surface this is not possible as there is a natural high temperature, but still this can drop, cooling the magma at a slow rate taking hundreds, thousands, or even millions of years. Weathering and Erosion Mechanical weathering physically breaks up rock. One example is called frost action or frost shattering. Water gets into cracks and joints in bedrock. Weathering is the process where rocks are dissolved, worn away or broken down into smaller and smaller pieces. Organic weathering happens when plants break up rocks with their growing roots or plant acids help dissolve rock. There are mechanical, chemical and organic weathering processes. Mechanical weathering physically breaks up rock. One example is called frost action or frost shattering. Water gets into cracks and joints in bedrock. When the water freezes it expands and the cracks are opened a little wider. Over time pieces of rock can split off a rock face and big boulders are broken into smaller rocks and gravel. Once the rock has been weakened and broken up by weathering it is ready for erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity. |