What can you infer about metamorphic rocks?

What can you infer about metamorphic rocks?

From the name ”metamorphic,” we can infer that these rocks were formed by being changed or metamorphosed from something else.

What inferences can you draw from the texture of an igneous rock?

The size of mineral crystals in an igneous rock generally indicates the rate at which the lava or magma cooled to form a rock. We can use the textures to infer the rate of cooling that the igneous rock went through during their formation.

What are the three types of rock according to origin?

There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water.

What can you infer on the formation of sedimentary rock?

For sediment to become sedimentary rock, it usually undergoes burial, compaction, and cementation. Clastic sedimentary rocks are the result of weathering and erosion of source rocks, which turns them into pieces—clasts—of rocks and minerals. They are most often transported by water and deposited as layers of sediment.

What is obsidian rock made of?

obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass.

What makes a rock different from other rocks?

Rocks are made of minerals. Rocks can be a mixture of different kinds of minerals, a mixture of many grains of the same kind of mineral, or a mixture of different grains of rocks. When you split a rock into very small pieces, the pieces are different from each other.

What makes a rock look like an igneous rock?

These coarse-grained crystals make the rock look sugary as the flat crystal faces reflect the light in hundreds of little sparkles. The name of the igneous rock depends on what minerals are present. If there are lots of light-colored minerals and the rock is coarse grained, it is granite.

Which is an example of a porphyritic igneous rock?

Phenocrysts are the crystals surrounded by the matrix; these are usually large, straight-sided, and glassy minerals unless they have been weathered. Porphyritic is used as an adjective to modify the name of any fine-grained igneous rock that has less than 50% phenocrysts in it. Example: Porphyritic basalt, porphyritic andesite.

How are fossils used to date sedimentary rocks?

Of course, fossils can be used to date sedimentary rocks, but equally importantly, they tell us a great deal about the depositional environment of the sediments and the climate at the time.