Ningejibu kwa kiswahili ila bahati mbaya elimu niliyoipata sijafundishwa kwa kiswahili
Sedimentary rocks are formed through the gradual accumulation of
for example, sand on a beach or mud on a river bed. As the sediments are buried they get compacted as more and more material is deposited on top.
Eventually the sediments will become so dense that they would essentially form a rock . This process is known as lithification .
Igneous rocks are rocks which have crystallized from a melt or
The melt is made up of various components of pre-existing rocks which have been subjected to melting either at subduction zones or within the Earth 's mantle. The melt is hot and so passes upward through cooler country rock .
As it moves it cools and various rock types
will form through a process known as fractional crystallization .
Igneous rocks can be seen at mid ocean ridges, areas of island arc volcanism or
in intra-plate hotspots .
Metamorphic rocks are rocks which once existed as igneous or
sedimentary rocks but have been subjected to varying degrees of
pressure and heat within the Earth's crust.
The processes involved will
change the composition and fabric of the rock and their original nature is often hard to distinguish. Metamorphic rocks are typically found in areas of mountain building .