Given a passage and a query based on the passage, generate an unambiguous, concise and simple answer to the query from information in the passage. Note that the answer may not be present in exact form.
Q: 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. As the adjacent diagram illustrates, each of the types of rocks is altered or destroyed when it is forced out of its equilibrium conditions. An igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. 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. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle During the rock cycle process, sedimentary rocks can become metamorphic or igneous rocks as they are buried in the planet's crust with younger layers of rock above them. Eventually they can metamorphose under heat and pressure at great depth, or melt to form new magma. Uplifting of rock layers by earth forces can bring rocks near the surface again at any point in the cycle. Igneous and metamorphic rocks can weather to form sediments that later become sedimentary rocks. Igneous rocks can metamorphose when subjected again to heat and pressure. Metamorphic rocks can metamorphose in repeat episodes or melt into magma, which later cools to form igneous rocks. Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill. It has a composition similar to gabbro. The difference between basalt and gabbro is that basalt is a fine-grained rock while gabbro is a coarse-grained rock. Basalt (pronounced /bslt/, /bslt/ or /bslt/) is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of lava basalt flows. A: Basalt is primarily formed by the extrusion of lava flows onto the surface of the earth during a volcanic eruption. The intrusion of a narrow sill or igneous dike below the crust also results in the formation of basalt. Basalt is a type of igneous rock that is typically dark in coloration with a fine-grained texture. It is the most predominant rock type found in Earth's crust, and mainly consists of pyroxene and plagioclase minerals. Volcanoes that form basalt are commonly found near the ocean basins. IGNEOUS ROCKS (obsidian, granite, scoria, basalt) - all samples seem to be hard and not breakable. GRANITE: Granite is an igneous rock that cooled very slowly. We know this because the minerals in granite are very large. It takes a long time (hundreds of thousands of years) for rocks to grow to visible size. BASALT: Basalt cooled more quickly than granite. A type of igneous rock. Basalt is the most common rock type in the earth's crust and makes up most of the ocean floor. A process that turns sediment into sedimentary rock. Over time, sediment accumulates in oceans, lakes, and valleys, eventually building up in layers and weighing down the material underneath. Molten rock that flows beneath the earth's surface and is made up of gases, liquids, and crystals. When magma reaches the surface, it is called lava. Marble A type of metamorphic rock formed when limestone is pushed down into the earth and subjected to intense heat and pressure for a long period of time. Melting dating: The global tectonic rock cycle that allow black lava, called basalt, to reach the surface. The portion that remains in a fissure below the surface usually forms a vertical black tubular body known as a dike (or dyke). Basalt Rocks Basalt is an extrusive igneous rock that is very dark in color. It is the most common type of rock in the Earth's crust and it makes up most of the ocean floor. It is made of many dark colored minerals such as pyroxene and olivine. Basalt also contains some light colored minerals such as feldspar and quartz, but the amounts are small. Query: how is basalt formed in rock cycle
A:
Basalt is primarily formed by the extrusion of lava flows onto the surface of the earth during a volcanic eruption.