Impact-Induced Hydrothermal Activity on Earth and Mars

Hdl Handle:
http://hdl.handle.net/10150/193511
Title:
Impact-Induced Hydrothermal Activity on Earth and Mars
Author:
Abramov, Oleg
Issue Date:
2006
Publisher:
The University of Arizona.
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.
Abstract:
While several lines of evidence strongly hint at the biological importance of impact-induced hydrothermal systems during the impact cataclysm at ~3.9 Ga, these systems are not well understood. There is unambiguous evidence of hydrothermal activity at many terrestrial craters, but the available samples represent a very limited number of crater diameters and locations within the crater. Therefore, computer models are crucial for learning how impact-induced hydrothermal systems work, how long they last, and whether they provide suitable environments for thermophilic microorganisms. This dissertation presents detailed simulations of hydrothermal activity at the terrestrial craters Chicxulub and Sudbury, as well as at range of crater sizes on early Mars. A well-established computer code HYDROTHERM was used. The models for terrestrial craters were constrained by seismic, magnetic, and gravity surveys, as well as petrological, mineralogical, and chemical analyses of samples (by others).Sudbury crater is ~180 km in diameter, and 1.85 Ga. Simulation results indicate that a hydrothermal system at Sudbury crater remained active for several hundred thousand to several million years, depending on assumed permeability, and produced habitable volumes of up to ~20,000 km^3.Chicxulub crater is also ~180-km in diameter, but only 65 Ma. The lifetime of the hydrothermal system ranges from 1.5 Ma to 2.3 Ma depending on assumed permeability. The temperatures and fluxes observed in the model are consistent with alteration patterns observed by others in borehole samples.Another set of simulations modeled post-impact cooling of hypothetical craters with diameters of 30, 100, and 180 km in an early Martian environment. System lifetimes, averaged for all permeability cases examined, were 67,000 years for the 30-km crater, 290,000 years for the 100-km crater, and 380,000 for the 180-km crater. Also, an ap-proximation of the thermal evolution of a Hellas-sized basin (~2000 km) suggests poten-tial for hydrothermal activity for ~10 Myr after the impact. The habitable volume reached a maximum of ~6,000 km^3 in the 180-km crater model.Possible morphological and mineralogical signs of hydrothermal activity in Martian craters were observed, both in this work and by others. These observations, while by no means definitive, are generally consistent with model predictions.
Type:
text; Electronic Dissertation
Keywords:
impact cratering; hydrothermal systems; Mars; numerical modeling; groundwater hydrology; astrobiology
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Planetary Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Kring, David A.
Committee Chair:
Kring, David A.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleImpact-Induced Hydrothermal Activity on Earth and Marsen_US
dc.creatorAbramov, Olegen_US
dc.contributor.authorAbramov, Olegen_US
dc.date.issued2006en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © 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.en_US
dc.description.abstractWhile several lines of evidence strongly hint at the biological importance of impact-induced hydrothermal systems during the impact cataclysm at ~3.9 Ga, these systems are not well understood. There is unambiguous evidence of hydrothermal activity at many terrestrial craters, but the available samples represent a very limited number of crater diameters and locations within the crater. Therefore, computer models are crucial for learning how impact-induced hydrothermal systems work, how long they last, and whether they provide suitable environments for thermophilic microorganisms. This dissertation presents detailed simulations of hydrothermal activity at the terrestrial craters Chicxulub and Sudbury, as well as at range of crater sizes on early Mars. A well-established computer code HYDROTHERM was used. The models for terrestrial craters were constrained by seismic, magnetic, and gravity surveys, as well as petrological, mineralogical, and chemical analyses of samples (by others).Sudbury crater is ~180 km in diameter, and 1.85 Ga. Simulation results indicate that a hydrothermal system at Sudbury crater remained active for several hundred thousand to several million years, depending on assumed permeability, and produced habitable volumes of up to ~20,000 km^3.Chicxulub crater is also ~180-km in diameter, but only 65 Ma. The lifetime of the hydrothermal system ranges from 1.5 Ma to 2.3 Ma depending on assumed permeability. The temperatures and fluxes observed in the model are consistent with alteration patterns observed by others in borehole samples.Another set of simulations modeled post-impact cooling of hypothetical craters with diameters of 30, 100, and 180 km in an early Martian environment. System lifetimes, averaged for all permeability cases examined, were 67,000 years for the 30-km crater, 290,000 years for the 100-km crater, and 380,000 for the 180-km crater. Also, an ap-proximation of the thermal evolution of a Hellas-sized basin (~2000 km) suggests poten-tial for hydrothermal activity for ~10 Myr after the impact. The habitable volume reached a maximum of ~6,000 km^3 in the 180-km crater model.Possible morphological and mineralogical signs of hydrothermal activity in Martian craters were observed, both in this work and by others. These observations, while by no means definitive, are generally consistent with model predictions.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectimpact crateringen_US
dc.subjecthydrothermal systemsen_US
dc.subjectMarsen_US
dc.subjectnumerical modelingen_US
dc.subjectgroundwater hydrologyen_US
dc.subjectastrobiologyen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlanetary Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorKring, David A.en_US
dc.contributor.chairKring, David A.en_US
dc.contributor.committeememberBaker, Victor R.en_US
dc.contributor.committeememberMcEwen, Alfred S.en_US
dc.contributor.committeememberMendelson, Neil H.en_US
dc.contributor.committeememberTurtle, Elizabeth P.en_US
dc.identifier.proquest1580en_US
dc.identifier.oclc137356519en_US
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