Origin of the Martian global dichotomy by crustal thinning in the late Noachian or early Hesperian

Journal Article · Fri Aug 10 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB08p12595· OSTI ID:5013196

McGill, G E; Dimitriou, A M ^[1]

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1. Univ. of Massachusetts, Amherst (United States)

The marked dichotomy in topography, surface age, and crustal thickness between the northern lowland and southern upland Mars has been explained as due to an initially inhomogeneous crust, a single mega-impact event, several overlapping large basin impacts, and first-order convective overturn of the martian mantle. All of the published hypotheses propose that the dichotomy was formed early in martian history; before the end of the primordial heavy bombardment. A primordial origin is inherent in the initial crustal inhomogeneity hypothesis, and required for both impact hypotheses. Endogenic hypotheses are not so constrained. Geological data indicate episodes of fracturing and faulting in the late Noachian and the early Hesperian. This fracturing and faulting occurred primarily within the northern lowland and along the boundary between lowland and highland. Igneous activity also peaked in the late Noachian and early Hesperian. These data suggest a tectonic event near the Noachian/Hesperian boundary characterized by enhanced heat loss and extensive fracturing, including formation of the faults that define much of the highland/lowland boundary. The authors argue that the major result of this tectonic event was formation of the dichotomy by thinning of the crust above a large convection cell or plume.

• OSTI ID: 5013196
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:B8; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640000* -- Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AGE ESTIMATION
DIMENSIONS
ENERGY LOSSES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
HEAT LOSSES
IMPACT SHOCK
LOSSES
MARS PLANET
PLANETARY EVOLUTION
PLANETS
SOLAR SYSTEM EVOLUTION
TECTONICS
THICKNESS
TOPOGRAPHY