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10 - The Tectonic Character of Mercury
- Edited by Sean C. Solomon, Larry R. Nittler, Carnegie Institution of Washington, Washington DC, Brian J. Anderson
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- Book:
- Mercury
- Published online:
- 10 December 2018
- Print publication:
- 20 December 2018, pp 249-286
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Summary
Mercury is a tectonic world: the planet has experienced a long and complicated history of deformation, recorded by its preserved tectonic landforms. As the study of tectonics naturally intersects with volcanology, chemistry, interior structure, and thermal evolution, understanding the tectonic character of Mercury is a crucial means by which to more fully comprehend the planet’s geological history. In this chapter, we seek to tie together the various strands of observational and analytical studies of the tectonics of Mercury conducted since the first Mercury flyby of the MESSENGER mission. We describe the shortening and extensional structures on the innermost planet, as well as an enigmatic set of long-wavelength topographic warps that may have been tectonically driven, before reviewing our understanding of the structure and properties of Mercury's lithosphere. The mechanisms for tectonic deformation are next discussed, and we then explore the other major aspect of Mercury's tectonics – when deformation took place – as we work to describe at least in broad terms the tectonic history of the planet. The influence of tectonics on Mercury's volcanic activity is then addressed. Finally, we list some major questions regarding Mercury’s tectonics that remain open and suggest how they might yet be answered.
11 - The Volcanic Character of Mercury
- Edited by Sean C. Solomon, Larry R. Nittler, Carnegie Institution of Washington, Washington DC, Brian J. Anderson
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- Book:
- Mercury
- Published online:
- 10 December 2018
- Print publication:
- 20 December 2018, pp 287-323
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- Chapter
- Export citation
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Summary
Mercury is a volcanic world: the planet has experienced a geological history that included partial melting of the interior and the transport of magma to, and eruption onto, the surface. In this chapter, we review Mercury’s volcanic character, first in terms of effusive volcanism (as characterized by lava plains, erosional landforms, and spectral characteristics), next in regard to the planet’s explosive volcanic activity, and then from the perspective of intrusive magmatism. We also visit the planet’s ancient yet spatially expansive intercrater plains and the prospect that they, too, are volcanic. We combine the observations of and inferences for Mercury’s smooth and intercrater plains to propose a model for the planet’s crustal stratigraphy. The extent of our understanding of the petrology of surface materials on Mercury is then discussed, including compositions and lithologies, mineral assemblages, physicochemical properties, and volatile contents. We then describe in broad terms the history of effusive and explosive volcanism on the planet, before addressing the influence that the planet’s lithospheric properties and tectonic evolution have played on volcanism. We finish by listing some major outstanding questions pertaining to the volcanic character of Mercury, and we suggest how those questions might best be addressed.