Answer:
The tectonic style and viability of modern plate tectonics in the early Earth is still debated. Field observations and theoretical arguments both in favor and against the uniformitarian view of plate tectonics back until the Archean continue to accumulate. Here, we present the first numerical modeling results that address for a hotter Earth the viability of subduction, one of the main requirements for plate tectonics. A hotter mantle has mainly two effects: 1) viscosity is lower, and 2) more melt is produced, which in a plate tectonic setting will lead to a thicker oceanic crust and harzburgite layer. Although compositional buoyancy resulting from these thick crust and harzburgite might be a serious limitation for subduction initiation, our modeling results show that eclogitization significantly relaxes this limitation for a developed, ongoing subduction process. Furthermore, the lower viscosity leads to more frequent slab breakoff, and sometimes to crustal separation from the mantle lithosphere. Unlike earlier propositions, not compositional buoyancy considerations, but this lithospheric weakness could be the principle limitation to the viability of plate tectonics in a hotter Earth. These results suggest a new explanation for the absence of ultrahigh-pressure metamorphism (UHPM) and blueschists in most of the Precambrian: early slabs were not too buoyant, but too weak to provide a mechanism for UHPM and exhumation.
Explanation:
Answer:
C. Involves a metal and a nonmetal.
Explanation:
Ionic compound involves a metal and a non-metal. Ionic compounds have electrovalent bonds between them.
These compounds are usually made up of metals and non - metals combining to form a unit.
- The metals usually has low electronegativity and transfers it electrons to the non - metal.
- The non-metal has high affinity for the electron.
- The electrostatic attraction between the ions formed results in the ionic bond.
Answer:
lower price and higher voltage capacity for the weight.
1. <span>C. accept an electron pair
2. </span><span>E. solid, liquid, and gas
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