Lithospheric displacement features on Europa and their interpretation
A geologic study of lithospheric displacements on the Jovian moon Europa reveals lateral motions and plate flexure. Tectonics are governed by the rotation rate, nature of the lithosphere and underlying decoupling layer, the nature and causes of lateral displacements, plus mechanisms for creating and...
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ftunivarizona:oai:repository.arizona.edu:10150/282707 2023-05-15T18:23:21+02:00 Lithospheric displacement features on Europa and their interpretation Tufts, Bruce Randall, 1948- Baker, Victor R. Greenberg, Richard J. 1998 http://hdl.handle.net/10150/282707 en_US eng The University of Arizona. http://hdl.handle.net/10150/282707 9901669 .b38806836 Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Geology Physics Astronomy and Astrophysics text Dissertation-Reproduction (electronic) 1998 ftunivarizona 2020-06-14T08:07:36Z A geologic study of lithospheric displacements on the Jovian moon Europa reveals lateral motions and plate flexure. Tectonics are governed by the rotation rate, nature of the lithosphere and underlying decoupling layer, the nature and causes of lateral displacements, plus mechanisms for creating and consuming surface area, and for restoring lithospheric rigidity. Astypalaea Linea is an 810-km-long strike-slip fault near the south pole, with 42 km of right-lateral offset, and includes a large pull-apart. Considering scale and contaminants, the lithosphere may have a tensile strength of ∼2.5 bars. The fault probably formed as a crack due to stresses from nonsynchronous rotation and diurnal tides, and was displaced by "walking" due to diurnal tides. Adjacent regional structures record earlier episodes of strike-slip. Wedge-shaped bands in the antijovian fracture zone are reconstructed, confirming the occurrence of block rotation and episodic dilation. A band on the leading side of the satellite is also reconstructed. Whether these bands formed under the influence of the same stress patterns which caused Astypalaea Linea is unclear; regional structures in the antijovian region suggest deformation by distributed shear. Dilation has also occurred across at least one ridge representative of a type independently interpreted as dilational based on ridge morphology. Other ridges apparently flex the underlying lithospheric plate downward. The lithosphere is inferred from flexural parameters at one locality to be 0.25-3.5 km thick. New lithosphere forms by ratchet-type spreading at bands and some ridges. Surface area may be removed by chaos formation or other processes. A global time marker based on a shift in ridge size is used to show that displacement was probably long-lived as well as widespread. During displacement, lithospheric plates were rigid and integral despite the appearance of cracks, perhaps due to annealing processes. Tides are the primary driving force for Europan tectonics and have produced a complex geologic history, consistent with Greenberg et al. (1997). A subsurface ocean, maintained by tidal heating, probably existed at the time of the displacements, which are relatively recent, and may well exist today. Thesis South pole The University of Arizona: UA Campus Repository South Pole |
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The University of Arizona: UA Campus Repository |
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ftunivarizona |
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English |
topic |
Geology Physics Astronomy and Astrophysics |
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Geology Physics Astronomy and Astrophysics Tufts, Bruce Randall, 1948- Lithospheric displacement features on Europa and their interpretation |
topic_facet |
Geology Physics Astronomy and Astrophysics |
description |
A geologic study of lithospheric displacements on the Jovian moon Europa reveals lateral motions and plate flexure. Tectonics are governed by the rotation rate, nature of the lithosphere and underlying decoupling layer, the nature and causes of lateral displacements, plus mechanisms for creating and consuming surface area, and for restoring lithospheric rigidity. Astypalaea Linea is an 810-km-long strike-slip fault near the south pole, with 42 km of right-lateral offset, and includes a large pull-apart. Considering scale and contaminants, the lithosphere may have a tensile strength of ∼2.5 bars. The fault probably formed as a crack due to stresses from nonsynchronous rotation and diurnal tides, and was displaced by "walking" due to diurnal tides. Adjacent regional structures record earlier episodes of strike-slip. Wedge-shaped bands in the antijovian fracture zone are reconstructed, confirming the occurrence of block rotation and episodic dilation. A band on the leading side of the satellite is also reconstructed. Whether these bands formed under the influence of the same stress patterns which caused Astypalaea Linea is unclear; regional structures in the antijovian region suggest deformation by distributed shear. Dilation has also occurred across at least one ridge representative of a type independently interpreted as dilational based on ridge morphology. Other ridges apparently flex the underlying lithospheric plate downward. The lithosphere is inferred from flexural parameters at one locality to be 0.25-3.5 km thick. New lithosphere forms by ratchet-type spreading at bands and some ridges. Surface area may be removed by chaos formation or other processes. A global time marker based on a shift in ridge size is used to show that displacement was probably long-lived as well as widespread. During displacement, lithospheric plates were rigid and integral despite the appearance of cracks, perhaps due to annealing processes. Tides are the primary driving force for Europan tectonics and have produced a complex geologic history, consistent with Greenberg et al. (1997). A subsurface ocean, maintained by tidal heating, probably existed at the time of the displacements, which are relatively recent, and may well exist today. |
author2 |
Baker, Victor R. Greenberg, Richard J. |
format |
Thesis |
author |
Tufts, Bruce Randall, 1948- |
author_facet |
Tufts, Bruce Randall, 1948- |
author_sort |
Tufts, Bruce Randall, 1948- |
title |
Lithospheric displacement features on Europa and their interpretation |
title_short |
Lithospheric displacement features on Europa and their interpretation |
title_full |
Lithospheric displacement features on Europa and their interpretation |
title_fullStr |
Lithospheric displacement features on Europa and their interpretation |
title_full_unstemmed |
Lithospheric displacement features on Europa and their interpretation |
title_sort |
lithospheric displacement features on europa and their interpretation |
publisher |
The University of Arizona. |
publishDate |
1998 |
url |
http://hdl.handle.net/10150/282707 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
http://hdl.handle.net/10150/282707 9901669 .b38806836 |
op_rights |
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
_version_ |
1766202930289967104 |