| 研究実績の概要 |
The research we proposed in our proposal was intended to understand the early (Noachian; a Hadean equivalent to Earth) tectonic condition of Mars in order to understand Martian heat loss mechanism. On Earth, such structures are totally resurfaced due to surface geological processes including plate tectonics and weathering. For this research we are considering both internal and external driving forces, i.e. behavior of early Mars’ internal mantle dynamics and impact induced dynamic behavior.
The second part of the research work was intended to understand the effect of Hellas impact in early Martian thinner crust (i.e. its control over generation of volcanoes and volcanoes in the surrounding region). For this purpose, I have collaborated with Prof. Masanori Kameyama from Ehime University and Prof. Kosuke Kurosawa from Chiba Institute of technology.
Currently, I am working on mapping of the compressional features (with focus on the Wrinkle Ridge) on a global scale. It is the initial phase to understand the orientation and distribution of the structures. My mapping will also help to understand the compressional zones on Mars (Ruj et al. in prep.).
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| 今後の研究の推進方策 |
Collaborating with Prof. Masanori Kameyama, I have been able to construct a numerical model to explain the extensional structures of southern highlands of Mars. Our model is also able to explain the volcanism surrounding the huge Hellas impact basin. We consider a time-dependent thermal convection of a fluid with an infinite Prandtl number and a temperature-dependent viscosity under the Boussinesq approximation in a cylinder. The height H and radius R of the cylinder are 2000 km and 4000 km (keeping morphology of the study area in mind), respectively, and the fluid in the modeled domain is heated both from bottom and from within. In order to reduce the computational costs as much as possible, the convection (however, convection on Mars is strongly questioned by the scientific community) is two-dimensionalized by imposing the axisymmetry around the vertical axis in the horizontal planes. However, in the later part we must adjust our initial condition with meteorite impacted and excavated crust.
After the completion of the mapping and I will discriminate the zones according to the morphology. Thereafter, wrinkle ridges from each discriminate zone will be used for morphometric analysis with the high-resolution satellite image sets. The digital elevation models will be assessed for the research. The ages extracted using Crater Size Frequency Distribution and estimation of strain will provide us better idea of Martian heat loss mechanism.
For future, I need to work on the altered initial condition by huge Hellas impact.
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