HR: 0800h
AN: P31C-0550    [Abstracts]
TI: Terrestrial Analogue and Origin of the Spiral Troughs in Martian Polar Ice Caps
AU: * Zeng, Z
EM: zuoxun.zeng@126.com
AF: Faculty of Earth Sciences,China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: * Zeng, Z
EM: zuoxun.zeng@126.com
AF: Department of Earth and Environmental Science, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: * Zeng, Z
EM: zuoxun.zeng@126.com
AF: Research Center of Space Science and Technology, China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: * Zeng, Z
EM: zuoxun.zeng@126.com
AF: Tectonomechanical Research Center, China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: Xie, H
AF: Department of Earth and Environmental Science, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Birnbaum, S
AF: Department of Earth and Environmental Science, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Liu, L
AF: Faculty of Earth Sciences,China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: Liu, L
AF: Tectonomechanical Research Center, China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: Zhu, M
AF: Department of Earth and Environmental Science, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, United States
AU: Zhu, M
AF: Research Center of GIS and RS, East China Institute of Technology, 56 Xuefu Road, Fuzhou, JX 344000, China
AU: Yang, W
AF: Faculty of Earth Sciences,China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AU: Yang, W
AF: Tectonomechanical Research Center, China University of Geosciences, 388 Lumo Road, Wuhan, HB 430074, China
AB: The characteristics and origin of spiral troughs in the Martian polar ice caps have been studied over three decades and it has been claimed that there is no terrestrial analogue of its kind. Several hypotheses have been proposed to explain the origin of the spiral troughs. However, it remains unclear how the spiral troughs form and what controls their spacing, orientation, curvature and spiral-out senses. To understand the formation and origin of spiral troughs on Mars, we first introduce and investigate its terrestrial analogue of vortex fracture systems developed and found in Earth's crust, though not in Earth's polar ice caps. One such pattern is found in Inner Mongolia of China. It consists of five arcuate fractures arranged in a spiral pattern. A second such pattern showing spiral or vortex principal stress trajectories is located in the Western Alpine arc with the center of the spiral stress field located around Torino, Italy. We propose a model of differential rotation between the permanently frozen inner part, and the movable outer part, of the Martian polar ice cap to explain the origin of spiral troughs. Observation of the Martian polar ice caps suggests this model. This model is further supported by physical modeling using a brittle-coating, by an analytic solution employing elasticity theory, and by finite element numerical modeling. Based on our preliminary study, the proposed new model explains the formation of spiral troughs in both the northern and southern polar ice caps with spiral arrangements displaying different spiral-out senses. The new model infers an increase in the rotational velocity of Mars during the past hundred thousands of years.
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
DE: 5422 Ices
DE: 5455 Origin and evolution
DE: 5462 Polar regions
DE: 5475 Tectonics (8149)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting