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A history of manufactured gas and natural gas
Published in Anthony N. Penna, A History of Energy Flows, 2019
Natural gas, composed of mostly methane is the cleanest fossil fuel. Like oil, the organisms that lived in the oceans millions of years ago provided the substance that eventually became oil and gas. While some organisms consumed others, those that remained became buried in overlaying ocean sediments. Increasing sediments subjected the surviving organic matter to steadily increasing temperatures and pressures. The rising temperatures reflected the heat from Earth’s mantle, referred to as the geothermal gradient. At greater depths of 7 kilometers, or more than 4.5 miles, temperatures greater than 230 degrees Celsius, or 446 degrees Fahrenheit, produce low molecular-weight hydrocarbons that make the formation of natural gas possible. Much of it migrates to the surface of the oceans and is released into the atmosphere as methane. Some of it is captured by impermeable rock or trapped shale. Millions of years later, modern civilization hungry for this stored energy tapped into these reserves to power industry and households.20
Earth Systems and Cycles
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Carbonate minerals and CO2 reach the deep Earth when subduction carries them into Earth’s mantle. Metamorphism associated with subduction, or during orogenesis, may cause new carbonate minerals to form, moving carbon from one mineral to another. The presence of calcite-rich veins in metamorphic rocks suggests that carbon may also move through the deep Earth when carbonate minerals dissolve in water and flow along cracks and fractures. Metamorphism may give way to igneous activity if temperatures get hot enough. When melting occurs, CO2 enters melts and is carried back toward the surface to be recycled.
Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Silicate groups of minerals are rock-forming material and constitute about 99% of the molten magma of the earth’s mantle and igneous rock. Silicate mineral consists of anions of silicon and oxygen atoms (SiO4)–n together with metallic cations of Al, Na, K, Fe, Ca, Mg and some other metals.
Convection in an internally cooled fluid layer heated from below
Published in Geophysical & Astrophysical Fluid Dynamics, 2018
Convection layers cooled or heated from within and heated or cooled at one boundary, while the other boundary is insulating, have received increasing attention in recent years. Many geophysical and astrophysical convection systems can be described in this way in first approximation. The Earth’s atmosphere is an example in that heating by solar radiation occurs at the ground, while heat is radiated into space in a more homogeneous way in the upper regions. See, for example, the discussion of Berlengiero et al. (2006). Plate tectonics is believed to be a manifestation of convection in the Earth’s mantle which is driven mainly by heat sources generated by the decay of radioactive elements. A similar situation occurs in the meltdown of a nuclear reactor and there are numerous other engineering examples where convection is driven by nearly homogeneous heating, while cooling occurs at a boundary.