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The key difference between igneous rocks and metamorphic rocks is that igneous rocks are the oldest rocks on earth, while metamorphic rocks are derivatives of igneous rocks and sedimentary rocks.Igneous rocks, and metamorphic rocks are the major three rock types in the earth’s crust. Geologist made this classification based on the geological process that formed these rocks. Igneous rocks are formed when melted rock or cools and solidifies while sedimentary rocks are formed when sediments get solidified. Metamorphic rocks, on the other hand, are rocks that have changed from igneous rocks or metamorphic rocks.
Like the water cycle, there exists a rock cycle (geological cycle) in geology. It is the process by which rocks are formed, degraded and reformed by the internal geological processes like plutonism, volcanism, uplift and/or by external geological processes like erosion, weathering, and deposition. What are Igneous Rocks?Igneous rocks are the oldest type of rocks on the earth. All the other types of rocks form from igneous rocks. Igneous rocks form when magma (molten materials) rise from the earth’s interior. We can classify these rocks further according to their depth of formation. The rocks that form below the earth surface are, while rocks that form on the earth surface are the (volcanic rocks).
There are 3 different types of rocks; igneous, sedimentary and metamorphic. Igneous rock is formed when magma or lava from volcanoes cools. Sedimentary rocks are formed over millions of years when sediments (tiny pieces of rocks and animal skeletons) are pressed together at the bottom of seas and rivers. Igneous and sedimentary rocks mainly undergo this change and become metamorphic rocks. The existing rock type which undergoes a change is referred to as the protolith. Hence, the study of metamorphic rocks provides an understanding of the pressure.
Figure 01: An Igneous RockThese rocks contain 40% to 80% silica. Magnesium and iron are important components among other components. Granite, pegmatite, gabbro, dolerite, and basalt are some examples of igneous rocks.
What are Metamorphic Rocks?Metamorphic rocks form due to metamorphism from existing igneous or sedimentary rocks, or even from existing metamorphic rocks. When existing rocks undergo changes due to high pressure and/or high temperature and/or high shearing stresses, metamorphic rocks form. What is the Difference Between Igneous Rocks and Metamorphic Rocks?The key difference between igneous rocks and metamorphic rocks is that igneous rocks are the oldest rocks on earth, while metamorphic are derivatives of igneous rocks and sedimentary rocks. Furthermore, Igneous rocks make up the major proportion (nearly 95%) of total rocks, while metamorphic rocks are present in a very small percentage.Moreover, igneous rocks are made up of two or more minerals, while metamorphic rocks are usually made up of only one mineral. So, this is also a significant difference between igneous rocks and metamorphic rocks. Besides, another important difference between igneous rocks and metamorphic rocks is that metamorphic rocks are harder than igneous rocks.
However, resistance to weathering and erosion is less in metamorphic rocks compared to igneous rocks. Also, the tendency to react with acids is higher in metamorphic rocks when compared to igneous rocks.Summary – Igneous Rocks vs Metamorphic RocksIgneous rocks, sedimentary rocks, and metamorphic rocks are the major three rock types in the earth’s crust.
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The key difference between igneous rocks and metamorphic rocks is that igneous rocks are the oldest rocks on earth while metamorphic are derivatives of igneous rocks and sedimentary rocks. “Igneous Rock: Definition, Classification, Types and Formation.” Rocks For Kids,. Image Courtesy:1. “Pumice” By via2. “Metamorphic rock talc” By Tiia Monto via.
Metamorphic rocksrocks are formed from other rocks that are changed because of heat or pressure. They are not made from molten rock – rocks that do melt form igneous rocks instead.Earth movements can cause rocks to be deeply buried or squeezed. As a result, the rocks are heated and put under great.
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They do not melt, but the minerals they contain are changed chemically, forming metamorphic rocks. Metamorphic rocks may form from rocks heated by nearby magma What are metamorphic rocks like?Marble is formed from limestone and contains tiny interlocking grains. The layers in slate, formed from shale, are arranged in layers. This makes slate useful for making roof tiles because it can be split into separate flat sheets.
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