Hypervelocity impacts and the evolution of planetary surfaces and interiors

The thesis consists of five studies relating impact processes to the evolution of planetary interiors as well as impact structures on planetary surfaces. Chapter 2 is concerned with developing methods for estimating the amount of heat deposited deep in terrestrial mantles by large impacts. Chapter 3 makes use of these results to compute the consequences of impact-related thermal buoyancy perturbations in numerical models of subsolidus convection. Among the important results of this work is a relation for the time-scale on which a buoyancy anomaly flattens and spreads before it is halted by convective downflows, as well as a condition that indicates for what perturbation magnitudes and Rayleigh numbers the flow is significantly slowed at a global scale. Chapter 4 describes a structural model of Endurance Crater in Meridiani Planum on Mars, which is constrained by observations gathered by the MER-B Opportunity rover. These results reveal new insights about the planform shape of the crater excavation flow, as well as the connection between crater shape and pre-existing structures in target materials. The study presented in chapter 5 relates the planimetric shape of simple impact craters on Mars (D < 5 km) to the geological targets in which they form, as well as rim diameter. Planform crater shape is characterized by a suite of morphometric parameters, including Fourier harmonic amplitudes and phase angles, as well as measures of deviation from radial symmetry and convexity.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Watters, Wesley Andrés, 1976-

Advisor dc:contributor.advisor

• Maria T. Zuber and John P. Grotzinger.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/46806

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/46806