The lithosphere is made up of different types of rock. They are classified depending on mode of formation as igneous, sedimentary and metamorphic rocks. The igneous rocks are the oldest types of rocks. Igneous is a Greek word meaning fire. These rocks are formed as a result of heating up of the earths crust to form magma. When magma cools slowly beneath the earths surface it forms coarse grained intrusive igneous rocks. When the magma due to earthquakes or volcanic eruption is extruded into the surface of the earth it is called lava. The fast cooling of the lava on the earth surface leads to formation of fine grained extrusive igneous rocks. The lava may be extruded into the air or in the ocean. Basalt is the igneous rock that results when these eruptions occurs in the ocean and forms most of the earth crust in the oceans. Other examples of igneous rocks include granite, gabbro, scoria, kimberlite, pumice etc Analysis: The three main processes in the sea are erosion, transportation and deposition of materials and debris in the sea. Wave erosion occurs when waves produced in the sea posses so much energy and erode the rocks at the coastline.