Rocks and Minerals
The Rock Cycle
- Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains).
- The earth's surface is shaped in part by the motion of water (including ice) and wind over very long times, which acts to level mountain ranges. Rivers and glacial ice carry off soil and break down rock, eventually depositing the material in sediments or carrying it in solution to the sea.
- Sediments of sand and smaller particles (sometimes containing the remains of organisms) are gradually buried and are cemented together by dissolved minerals to form solid rock again.
- Sedimentary rock buried deep enough may be re-formed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it.
- Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers.
- Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms.
- The earth first formed in a molten state and then the surface cooled into solid rock.
What are the three types of rock?
What is the rock cycle?
How are metamorphic rocks formed?
How are sedimentary rocks formed?
What is sedimentation?
How does sediment form?
What is weathering?
What is erosion?
What is deposition?
What is compaction?
What is cementation?
How are igneous rocks formed?
What is lava?
What is magma?
What types of rocks are formed from the processes of weathering and erosion, and compaction and cementation of sediment?
What types of rocks are formed from the processes of intense heat and pressure?
What type of rocks are formed from the processes of melting, cooling, and hardening of lava and/or magma?
Key Content Vocabulary:
- Asthenosphere – the somewhat fluid portion of the mantle upon which the lithosphere is located
- Cementation – process of binding and hardening sediments into hard rock
- Compaction – process by which overlying pressure from rocks and soil reduces the size or volume of sediments
- Compositional layers – structural layers of Earth defined by the materials from which they are made
- Core – the central region of the Earth; primarily made of nickel and iron
- Igneous – a type of rock formed when crystallized through melting and cooling rock
- Lithosphere – the solid and rigid outer layer of the Earth consisting of the crust and the solid portion of the upper mantle; positioned between the atmosphere and the asthenosphere
- Mantle – the region inside the Earth between the core and the crust
- Mechanical layers – structural layers of Earth defined on the basis of how materials act
- Mesosphere – the region of the mantle beneath the lithosphere and asthenosphere, but above the outer core
- Metamorphic – a type of rock formed when igneous or sedimentary rocks are put under intense heat and / or pressure in the Earth’s crust
- Plasticity – the quality of being easily shaped or molded
- Rock cycle – the continual process by which rocks can be changed into different types of rock
- Sedimentary – a type of rock formed through the accumulation, compaction, and cementation of sediment
- Sedimentation – the deposition of solid material from being suspended in a fluid (water)
- Semi-solid – having the qualities of both a solid and a liquid; exceptionally thick substance
- Inner core
- Lower mantle
- Outer core
- Upper mantle