Dichotomy in crustal melting on early Mars inferred from antipodal effect
Summary: The Martian crustal dichotomy (MCD) between the southern highlands and the northern lowlands is the planet’s most ancient crustal structure, but its origins and evolution remain enigmatic. Understanding of the MCD comes largely from present-day and shallow crustal constraints. Lacking ancie...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-09-01
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| Series: | The Innovation |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666675822000765 |
| _version_ | 1811294786563342336 |
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| author | Lei Zhang Jinhai Zhang Ross N. Mitchell |
| author_facet | Lei Zhang Jinhai Zhang Ross N. Mitchell |
| author_sort | Lei Zhang |
| collection | DOAJ |
| description | Summary: The Martian crustal dichotomy (MCD) between the southern highlands and the northern lowlands is the planet’s most ancient crustal structure, but its origins and evolution remain enigmatic. Understanding of the MCD comes largely from present-day and shallow crustal constraints. Lacking ancient and deeper constraints, hypotheses for the origin of the MCD range from an early giant impact, partial melting from sustained mantle convection, or some combination. We investigate with seismological modeling the best-preserved case of the “antipodal effect”—energy from an impact that concentrates and induces uplift and fracturing promoting volcanism at its antipode—the Hellas crater and the Alba Patera volcano on Mars. The volcano is latitudinally offset ∼2° (∼119 km) from the expected antipode, and we explore whether the MCD can explain this deflection. Variations across the MCD in topography, thickness, and composition have only minor effects. Simulations capable of sufficiently decelerating southern surface waves require the presence of 2%–5% more partial melt in the southern highlands. As the age of impact ca. 4 billion years ago post-dates the formation of the MCD, our partial melting results thus imply that, with or without an early giant impact, the MCD was modified by mantle convection in order to supply enough heat for crustal melts for several hundreds of millions of years after Mars formation. |
| first_indexed | 2024-04-13T05:22:40Z |
| format | Article |
| id | doaj.art-205399716d0f4fbdb957c963374fd70f |
| institution | Directory Open Access Journal |
| issn | 2666-6758 |
| language | English |
| last_indexed | 2024-04-13T05:22:40Z |
| publishDate | 2022-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | The Innovation |
| spelling | doaj.art-205399716d0f4fbdb957c963374fd70f2022-12-22T03:00:42ZengElsevierThe Innovation2666-67582022-09-0135100280Dichotomy in crustal melting on early Mars inferred from antipodal effectLei Zhang0Jinhai Zhang1Ross N. Mitchell2Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China; Corresponding authorState Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Corresponding authorSummary: The Martian crustal dichotomy (MCD) between the southern highlands and the northern lowlands is the planet’s most ancient crustal structure, but its origins and evolution remain enigmatic. Understanding of the MCD comes largely from present-day and shallow crustal constraints. Lacking ancient and deeper constraints, hypotheses for the origin of the MCD range from an early giant impact, partial melting from sustained mantle convection, or some combination. We investigate with seismological modeling the best-preserved case of the “antipodal effect”—energy from an impact that concentrates and induces uplift and fracturing promoting volcanism at its antipode—the Hellas crater and the Alba Patera volcano on Mars. The volcano is latitudinally offset ∼2° (∼119 km) from the expected antipode, and we explore whether the MCD can explain this deflection. Variations across the MCD in topography, thickness, and composition have only minor effects. Simulations capable of sufficiently decelerating southern surface waves require the presence of 2%–5% more partial melt in the southern highlands. As the age of impact ca. 4 billion years ago post-dates the formation of the MCD, our partial melting results thus imply that, with or without an early giant impact, the MCD was modified by mantle convection in order to supply enough heat for crustal melts for several hundreds of millions of years after Mars formation.http://www.sciencedirect.com/science/article/pii/S2666675822000765Marsantipodal effectcrustal meltingHellas basinAlba Patera |
| spellingShingle | Lei Zhang Jinhai Zhang Ross N. Mitchell Dichotomy in crustal melting on early Mars inferred from antipodal effect The Innovation Mars antipodal effect crustal melting Hellas basin Alba Patera |
| title | Dichotomy in crustal melting on early Mars inferred from antipodal effect |
| title_full | Dichotomy in crustal melting on early Mars inferred from antipodal effect |
| title_fullStr | Dichotomy in crustal melting on early Mars inferred from antipodal effect |
| title_full_unstemmed | Dichotomy in crustal melting on early Mars inferred from antipodal effect |
| title_short | Dichotomy in crustal melting on early Mars inferred from antipodal effect |
| title_sort | dichotomy in crustal melting on early mars inferred from antipodal effect |
| topic | Mars antipodal effect crustal melting Hellas basin Alba Patera |
| url | http://www.sciencedirect.com/science/article/pii/S2666675822000765 |
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