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Paths to the Energy Miracles
Published in H. B. Glushakow, Energy Miracles, 2022
Figure 125 is a diagram of the cross-sectional area of the Earth. The Earth’s crust is 35 km (21 miles) thick on average. At the boundary between crust and mantle, temperatures range from 500 to 1000°C (932 to 1864°F). At the deeper levels of the mantle bordering on the outer core, the temperature rises to 4000°C (7230°F).
Petroleum Pre-Period
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Temperature and pressure both modify the minerals’ crystal structural forms. The earth’s mineral materials exist in solid as well as in liquid forms because of temperature and pressure effects. Temperature and pressure increase with depth but not uniformly. The temperature gradient in the crust is 10–50°C/km. The average temperature gradient of the earth is 30°C/km. In deeper zones the temperature gradient is much higher. The crust is made of heterogeneous solid minerals. The upper mantle is in a mixed solid/plastic state. This is because different layers of minerals have different melting points. The temperature ranges from 300 to 900°C at the boundary between the crust and mantle. The temperature is as high as 4000°C at the border of the lower mantle and outer core. The outer core contains mainly Fe–Ni alloy in a liquid state because of high temperatures. The temperature between the inner and outer core boundary is 5400°C. The inner core of the earth is a solid state of dominant Fe–Ni alloy. Deep inside the inner core the temperature is as high as 7000°C.
Our Earth, its minerals and ore bodies
Published in Odwyn Jones, Mehrooz Aspandiar, Allison Dugdale, Neal Leggo, Ian Glacken, Bryan Smith, The Business of Mining, 2019
Odwyn Jones, Mehrooz Aspandiar, Allison Dugdale, Neal Leggo, Ian Glacken, Bryan Smith
The main driving force for the movement of the lithospheric plates comes from the Earth’s internal heat energy, which is primarily driven by radioactive decay of elements such as uranium and residual heat from the formation of the planet 4.55 billion years ago. Within the mantle, heat is transferred by convection in which hot rocks rise upwards but as they cool they begin to sink leading to the formation of convection cells. In areas where the litho-sphere is extended or thinned, the asthenosphere will be closer to the earth’s surface which can focus the upwelling hot rocks which leads to the melting of the asthenosphere below the lithosphere boundary and the intrusion of hot primary mantle derived magma. The volume of the intruded magma forces the lithospheric plates to push apart and separate. The episodic nature of ocean basin opening and closing was first noted by John T Wilson in the early 1960s and is known as the Wilson Cycle (Wilson, 1963). Recent, seismic tomography maps of the Earth’s interior show zones of fast and slow seismic S-wave velocity (Wookey and Dobson, 2008). Data collected from depths of ~ 2770 km in the lowermost part of the lower mantle shows two major areas of low S-wave velocity which are interpreted to represent gigantic mantle plumes named Great African and Central Pacific super plumes. It is suggested that the presence and magmatism associated of these super plumes may initiate lithospheric plate movement.
Scientific ocean drilling in the Australasian region: a review
Published in Australian Journal of Earth Sciences, 2022
While plate tectonics represents the dominant process creating and modifying the Earth’s surface topography (modified also by erosion and deposition), mantle plumes are a style of mantle convection that is prominent in surface expression as oceanic plateaus (and subaerial volcanic buildups when on continental crust) and chains of islands, atolls and seamounts (Wilson, 1963). Numerous examples of these are developed in the Australasian region. Initial magma production upon arrival of a decompressing and expanding plume head at the Earth’s surface can be sufficient to create basaltic crustal thicknesses, over a few million years, equivalent to the average continental crust (∼35 km, e.g. Hill et al., 1992), as was the case with the Ontong Java Nui plateau (Chandler et al., 2015). These massive effusions are also known as large igneous provinces (LIPs). The Ontong Java Nui plateau has disaggregated into the Ontong Java, Manihiki, and Hikurangi plateaus (Taylor, 2006). Arrival of oceanic plateaus at subduction zones is a primary mechanism leading to reversal in the respective geometry of subducting and overriding plates, e.g. Ontong Java adjacent to the Solomons and New Hebrides arcs, or the partial jamming of the subduction zone, e.g. the Hikurangi Plateau adjacent to the North Island of New Zealand.
Study of Love-type wave propagation in an isotropic tri layers elastic medium overlying a semi-infinite elastic medium structure
Published in Waves in Random and Complex Media, 2018
Amares Chattopadhyay, Pooja Singh, Pulkit Kumar, Abhishek Kumar Singh
The study of seismic waves in heterogeneous layered media allows us to make inferences about certain properties of Earth interior through which the wave travels. It can be seen that the applications of seismic waves are in various engineering fields likewise, crystal physics and solid Earth geophysics. To study the effects of heterogeneities of the crust on the dispersion curves, it is desirable to consider an Earth model in which the layers are taken to be heterogeneous. It is known that the materials in the Earth may not homogeneous rather their elastic properties vary with depth from one region to another. The interior structure of Earth is a form of layers and is divided into silicate solid crust, highly viscous mantle, and liquid outer core. The internal structure of the Earth is based on observation of topography and bathymetry, samples taken to the surface from greater depths by volcanic activity [1].
High-pressure studies on electronic and mechanical properties of FeBO3 (B = Ti, Mn, Cr) ceramics – a first-principles study
Published in Phase Transitions, 2018
N. Kishore, V. Nagarajan, R. Chandiramouli
In recent decades, the perovskite nanostructured materials are of technological interest among research community owing to their tunable properties such as superconductivity, ferroelectricity, piezoelectricity and colossal magnetoresistance [1–4]. Investigations of perovskites-based compounds under high pressure are useful to fine-tune its electronic and mechanical properties [5]. Moreover, the lower mantle of the Earth and other planets is composed of perovskite structure ((Fe, Mg)(Al, Si)O3). FeTiO3 exhibits a large electric conductivity at ambient conditions, which provides electric conduction in the earth interiors [6]. FeTiO3 has a wide band gap of around 2.54 eV and have antiferromagnetic property [7]. Due to its wide band gap and antiferromagnetic property, FeTiO3 is suitable for spintronics, integrated circuits, and radiation immune solar cells [8,9]. FeTiO3 can be prepared by a variety of methods, namely sol–gel, colloid emulsion technique, ball-milling and solid-state reaction between oxides in vacuum and high-temperature environment [10,11]. The advancement in communication systems and microelectronics leads to the miniaturization of antiferromagnetic materials. However, to achieve high antiferromagnetic property in small volume, the particle size should be reduced to tune its magnetic and semiconducting properties.