How do you introduce igneous rocks?
Introduction to Igneous Rocks An igneous rock is any crystalline or glassy rock that forms from cooling of a magma. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase.
What are two ways to describe igneous rocks?
The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.
What are three classifications of igneous rock?
Igneous rocks may be simply classified according to their chemical/mineral composition as felsic, intermediate, mafic, and ultramafic, and by texture or grain size: intrusive rocks are course grained (all crystals are visible to the naked eye) while extrusive rocks may be fine-grained (microscopic crystals) or glass ( …
What is the introduction of rock?
Rocks are aggregates of different mineral grains and can be divided into three major families or rock groupings. First are the Igneous (or “fire-formed”) Rocks, usually created by outpourings from various volcanoes or by cooling deep under the crust.
Which term best describes igneous rocks?
igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth material. Igneous rocks constitute one of the three principal classes of rocks, the others being metamorphic and sedimentary.
What is igneous rock used for?
One of the most common igneous rocks is granite (Figure 4.1). Granite is used extensively in building materials and making statues. Perhaps you have used a pumice stone to smooth your skin or to do jobs around the house. Pumice is another example of an igneous rock (Figure 4.2).
Who discovered igneous rocks?
The rock was described by Moore and Hayness (1920, pp. 183-187) and they gave credit for its discovery to T. S. Harrison of Denver, Colo. The rock is an igneous breccia or aglomerate comprising a ground-mass of basalt and inclusions consisting principally of shale in various stages of alteration.
How are igneous rocks named?
The word igneous is derived from the Latin ignis, meaning “of fire”. Volcanic rocks are named after Vulcan, the Roman name for the god of fire. Intrusive rocks are also called “plutonic” rocks, named after Pluto, the Roman god of the underworld.
How are the minerals in igneous rocks arranged?
These eight minerals form the bulk of igneous rocks. They are arranged in Bowen’s Reaction Series (BRS) by temperature of formation, high temperature ones at the top and low temperature ones at the bottom. Although it is useful to know these minerals they are not essential for a basic understanding of igneous rocks.
What’s the name of the molten rock at the surface?
Below the surface the molten rock is called magma; at the earth’s surface it becomes lava, although nothing has changed except the name. The fresh magma is white hot, brillant enough that you would have trouble looking at it. But as it cools it turns yellow, and then various shades of red.
How are igneous rocks similar to the Moon?
O ne of the most important ideas geology has discovered is that igneous rocks evolve. That the earth began with a composition similar to that of the moon, that is, composed mostly of an mafic/ultramafic parent rock, and from that simple beginning all the other rocks have evolved through a sequence of fractionation processes.