What is igneous sedimentary and metamorphic rocks

Login or Register to add to your saved resources. Different combinations of minerals form rocks; minerals are made of elements. There are 3 different types of rocks; igneous, sedimentary and metamorphic. Igneous rock is formed when magma or lava from volcanoes cools. Examples include basalt and granite. Most igneous rock is very hard. Some of the most spectacular rock formations on our planet are made of igneous rock; in Britain we see granite shapes called tors in south-western locations like Bodmin Moor, Dartmoor and Land's End.

Download fantastic science resources today! Experiments And Science Fun pack Science Learning Programme for each school year All the instructions, questions and information you need. Download FREE resources. Sedimentary rocks are formed over millions of years when sediments tiny pieces of rocks and animal skeletons are pressed together at the bottom of seas and rivers.

Examples include sandstone, coal and chalk. Some sedimentary rocks contain fossils bones or shells of living things that were buried long ago and have turned to stone. Variations in these two factors have created many different types of igneous rocks. When the magma cools at different rates, it creates different sized minerals. Quick cooling magmas have small minerals with the exception of obsidian, which is actually composed of silica, but has no crystalline structure. Basalt, for example, has small minerals, most of which can only be seen under a microscope.

Quick cooling lavas are called volcanic rocks. Magma that cools slowly creates rocks like granite, which have large minerals that can be seen with the naked eye. These igneous rocks cool inside the lithosphere, and are called plutonic rocks. Clastic material pieces of other rocks or fragments of skeletons may become cemented together and chemical precipitation and evaporation can form sedimentary rocks.

Organic sedimentary rocks, like coal, form from hard, biological materials like plants, shells, and bones that are compressed into rock.

The formation of clastic and organic rocks begins with the weathering , or breaking down, of the exposed rock into small fragments. Through the process of erosion , these fragments are removed from their source and transported by wind, water, ice, or biological activity to a new location. Once the sediment settles somewhere, and enough of it collects, the lowest layers become compacted so tightly that they form solid rock.

Chemical sedimentary rocks, like limestone, halite, and flint, form from chemical precipitation. A chemical precipitate is a chemical compound—for instance, calcium carbonate, salt, and silica—that forms when the solution it is dissolved in, usually water, evaporates and leaves the compound behind. These dissolved minerals are precipitated when the water evaporates. Metamorphic Rocks Metamorphic rocks are rocks that have been changed from their original form by immense heat or pressure.

Metamorphic rocks have two classes: foliated and nonfoliated. When a rock with flat or elongated minerals is put under immense pressure, the minerals line up in layers, creating foliation. Foliation is the aligning of elongated or platy minerals, like hornblende or mica, perpendicular to the direction of pressure that is applied. An example of this transformation can be seen with granite, an igneous rock.

Granite contains long and platy minerals that are not initially aligned, but when enough pressure is added, those minerals shift to all point in the same direction while getting squeezed into flat sheets. Nonfoliated rocks are formed the same way, but they do not contain the minerals that tend to line up under pressure and thus do not have the layered appearance of foliated rocks.

Sedimentary rocks like bituminous coal, limestone, and sandstone, given enough heat and pressure, can turn into nonfoliated metamorphic rocks like anthracite coal, marble, and quartzite. Nonfoliated rocks can also form by metamorphism, which happens when magma comes in contact with the surrounding rock. The dark brown rounded minerals are garnet, and everything you see with a whiteish tint is the mica.

The reddish areas are rusty mica. Image modified from Willowleaf Minerals. Sediment is a naturally occurring material that is broken down by the processes of weathering and erosio n a nd is subsequently naturally transported or not.

An old, red sandstone. Image via Ian Hopkinson. They typically contain very fine particles and are transported as suspended particles by turbulent flow in water or air, depositing once the flow settles. In other words, most limestone you see today comes from the skeletons of organisms such as corals, mollusks, and foraminifera. Coal is another example of biochemical rock. There are also other types of specific sedimentary rocks — for example , the ones formed in hot springs.

As I mentioned wit h bi ochemical rocks, fossils can become rocks in time.