Chemical Composition and Layering of Earth
E. Suess has thrown light on the chemical composition of the earth’s interior. The crust is covered by a thin layer of sedimentary rocks of very low density. There are three major and almost concentric layers in the earth. E. Suess explains these, and they are SIAL, SIMA and NIFE.
SIAL
It is the topmost layer of the earth found just below the sedimentary thin cover of the crust. Silicon (Si) and Aluminum (Al) are two very important elements found in abundance in this layer. They are named SIAL.
The average density of this layer is 2.75 to 2.90 g/cm3, and its average depth is 40 km. It is very thin below oceanic water (5 to 10 km), but below the mountains, it is very thick (up to 70 km). The main rock in this zone is granite.
SIMA
It is the second layer after SIAL from the surface towards the interior. It is named after Silicon (SI) and Magnesium (MA), as both elements are abundant in this layer. It is a very thick layer which goes almost up to a depth of 2900 km. It starts from a depth of 70 km below continents, while below the oceans, it is 5 to 10 km deep.
Its average density varies from 2.90 g/cm3 to 4.75 g/cm3. The main rocks in this layer are silicates of magnesium and iron. This layer is largely composed of basalt.
NIFE
It is the innermost layer of the earth. This layer is made up of Nickle (NI) and Ferrous (FE), and so it is named NIFE. It is just below the SIMA from a depth of 2900 km to the earth’s centre encircling from all directions.
Nickle and Ferrous are found here. They are very heavy and denser elements. Therefore, this layer has a higher density. Its density is about 11 to 12 g/cm3. It is believed that the existence of nickel and iron in the NIFE is the main cause of the earth’s magnetic properties.
Read More in Geomorphology
- Earth Movements: Meaning and Types
- Epeirogenic Earth Movements
- Orogenic Earth Movements
- Cymatogenic Earth Movements
- Concept of Stress and Strain in Rocks
- Folds in Geography
- Fault in Geography
- Mountain Building Process
- Morphogenetic Regions
- Isostasy: Concept of Airy, Pratt, Hayford & Bowie and Jolly
- Continental Drift Theory of Alfred Lothar Wegener (1912)
- Plate Tectonics: Assumptions, Evidences, Plate Boundaries and Features Formed
- Volcanoes: Process, Products, Types, Landforms and Distribution
- Earthquakes: Processes, Causes and Measurement
- Plate Tectonics and Earthquakes
- Composition and Structure of Earth’s Interior
- Artificial Sources to Study Earth’s Interior
- Natural Sources to Study Earth’s Interior
- Internal Structure of Earth
- Chemical Composition and Layering of Earth
- Weathering: Definition and Types
- Mass Wasting: Concept, Factors and Types
- Models of Slope Development: Davis, Penck, King, Wood and Strahler
- Davis Model of Cycle of Erosion
- Penck’s Model of Slope Development
- King’s Model of Slope Development
- Alan Wood’s Model of Slope Evolution
- Strahler’s Model of Slope Development
- Development of Slope
- Elements of Slope
- Interruptions to Normal Cycle of Erosion
- Channel Morphology and Classification
- Drainage System and Drainage Pattern
- River Capture or Stream Capture
- Stream Channel Pattern
- Fluvial Processes and Landforms: Erosional & Depositional
- Delta: Definition, Formation and Types
- Aeolian Processes and Landforms: Erosional & Depositional
- Desertification: Definition, Problem and Prevention
- Glacier: Definition, Types and Glaciated Areas
- Glacial Landforms: Erosional and Depositional
- Periglacial: Meaning, Processes and Landforms
- Karst Landforms: Erosional and Depositional
- Karst Cycle of Erosion
- Coastal Processes: Waves, Tides, Currents and Winds
- Coastal Landforms: Erosional and Depositional
- Rocks: Types, Formation and Rock Cycle
- Igneous Rocks: Meaning, Types and Formation
- Sedimentary Rocks: Meaning, Types and Formation
- Metamorphic Rocks: Types, Formation and Metamorphism
- Morphometric Analysis of River Basins
- Soil Erosion: Meaning, Types and Factors
- Urban Geomorphology: Concept and Significance
- Hydrogeomorphology: Concept, Fundamentals and Applications
- Economic Geomorphology: Concept and Significance
- Geomorphic Hazard- Earthquake: Concept, Causes and Measurement
- Geomorphic Hazard- Tsunami: Meaning and Causes
- Geomorphic Hazard- Landslides: Concept, Types and Causes
- Geomorphic Hazard- Avalanches: Definition, Types and Factors
- Integrated Coastal Zone Management: Concept, Objectives, Principles and Issues
- Watershed: Definition, Delineation and Characteristics
- Watershed Management: Objective, Practice and Monitoring
- Applied Geomorphology: Concept and Applications