Describe the nature and mode of origin of the main types of rock at the earth's crust.

Rocks at earth's crust are mostly igneous, sedimentary, metamorphic rocks. Nature and Mode of Origin of earth Igneous rocks: (1) Crystalline rocks & highly minerals content by Marble (2) Non-fossiliferous rocks B Origin → Magma based origin from interior of earth by Volcanic origin (Granite, Plutonic or intrusive rocks) Sedimentary: (1) By Fine sediments and extreme of rocks (2) Fossiliferous rocks Metamorphic rocks: (1) These are non-fossiliferous (2) Have nature of rocks it is composed of B Origin → Foliation and bending due to contact & thermal metamorphism here due to pressure & temperature rock changes by Gneiss → Granite slate → Limestone These deep in doing paleoclimatic, paleomagnetic, geomagnetic studies further of a region

QUICK: (1) Based on sedimentation and lithification process by Limestone, shale (2) Based on solidification of erosion materials Metamorphic rocks (1) These are non-fossiliferous (2) Have nature of rocks it is composed of B Origin → Foliation and bending due to contact & thermal metamorphism here due to pressure & temperature rock changes by Gneiss → Granite state → Limestone These deep in doing paleoclimatic, paleomagnetic, geomagnetic studies further of a region

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