What is a laccolith and a batholith?Im learning about rock formations, relative/absolute age, unconformities and such in my science class and on a paper it asks to describe what...

What is a laccolith and a batholith?

Im learning about rock formations, relative/absolute age, unconformities and such in my science class and on a paper it asks to describe what a  laccolith and a batholith are and i dont understand what they are. Please try to describe what they are to me, it would be greatly appriciated! :)

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trophyhunter1 | College Teacher | (Level 1) Educator Emeritus

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A Batholith is formed from igneous intrusive rock that is made of magma cooled within the Earth's crust. It consists of felsic rock--light colored rocks such as granite, diorite and others. Batholiths are large bodies of igneous rock. The magma is buoyant and rises through surrounding native rock. Therefore, when it cools, it solidifies 5 to 30 kilometers underground as plutons. When these plutons come together, they form a mammoth granitic rock formation called a batholith. An example is the Sierra Nevada Batholith. A laccolith is a sheet intrusion between two layers of sedimentary rock. Because the magma has pressure, it raises the overlying rock layers and it forms a dome shape. Magmas that crystallize to diorite, granite and granodiorite which cool underground, slowly over time, are found in laccoliths. When the surface sedimentary rock erodes over time, it leaves the igneous rock below. Devils Tower in Wyoming is an example of a laccolith.

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