when sedimentary rock is buried it may change into metamorphic rock. describe two causesof this change.
Check these sites.
http://www.athro.com/earth_science/rocks.html
http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry13.html
When sedimentary rock is buried, it may undergo a transformation and become metamorphic rock. There are two main causes for this change:
1. Increased Temperature: When sedimentary rocks are buried deep within the Earth's crust, they are exposed to higher temperatures. This increase in temperature can lead to the metamorphism of the rock. Heat causes the minerals within the sedimentary rock to recrystallize and rearrange their structures, resulting in the formation of new minerals and a change in the rock's texture.
The increase in temperature can be caused by several factors, such as geothermal gradient (the natural increase in temperature with depth), proximity to igneous intrusions or volcanic activity, or tectonic forces pushing the rocks deeper into the Earth's interior.
2. Increased Pressure: Burial of sedimentary rocks also leads to an increase in pressure. As layers of sediment accumulate over time, the weight of the overlying material puts immense pressure on the underlying sedimentary rocks. This pressure causes the minerals within the rock to rearrange and realign themselves, resulting in the development of new textures and structures characteristic of metamorphic rocks.
Pressure within the Earth's crust can stem from various sources like tectonic forces, lithostatic (confining) pressure, or even the weight of the overlying rock layers. The increase in pressure helps create conditions for the metamorphism of sedimentary rocks.
It is important to note that both temperature and pressure are interrelated and often occur simultaneously during the metamorphic process. These two factors, acting over long periods of time, alter the composition and structure of sedimentary rocks, ultimately transforming them into metamorphic rocks.