Rocks formed from the cooling lava of volcanic eruptions are
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When lava reaches the surface of the Earth through volcanoes or through great fissures the rocks that are formed from the lava cooling and hardening are called extrusive igneous rocks.
igneous rocks. Igneous rocks are formed when molten magma or lava cools and solidifies. When a volcanic eruption occurs, the hot lava is ejected from the volcano and exposed to the air or water, causing it to rapidly cool and harden. This process of cooling and solidification leads to the formation of igneous rocks.
To understand and identify rocks formed from the cooling lava of volcanic eruptions, we can follow these steps:
1. Study the Rock's Texture: Igneous rocks formed from volcanic lava usually have a fine-grained or glassy texture. This occurs because the lava cools quickly on the surface, preventing large mineral crystals from forming.
2. Look for Volcanic Features: Examine the rock for any visible volcanic features, such as vesicles (tiny holes) or gas bubbles. These features indicate that the rock was formed from volcanic eruptions.
3. Analyze the Composition: Determine the mineral composition of the rock by inspecting its color and texture. Common minerals found in volcanic igneous rocks include silica-rich minerals like quartz and feldspar, as well as dark-colored minerals like pyroxene and olivine.
4. Consult Geological Maps and Field Guides: To get more accurate identification, refer to geological maps or field guides specific to the area where the rock was collected. These resources can provide information on the geological history and types of volcanic rocks found in that region.
Remember, proper identification of igneous rocks formed from volcanic eruptions requires careful observation of the rock's texture, mineral composition, and appearance of any volcanic features. Consulting geological resources can also provide valuable information for identification.