|
|||||
|
|
Magnitude of global contraction on Mars from analysis of surface faults: Implications for martian thermal history |
|
| Authors: | Amanda L Nahm Richard A Schultz |
| Institution: | a Geomechanics - Rock Fracture Group, Department of Geological Sciences and Engineering, MS 172, University of Nevada, Reno, NV 89557-0138, United States b Center for Lunar Science and Exploration, USRA - Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058, United States c NASA Lunar Science Institute, United States |
| Abstract: | Faults provide a record of a planet’s crustal stress state and interior dynamics, including volumetric changes related to long-term cooling. Previous work has suggested that Mars experienced a pulse of large-scale global contraction during Hesperian time. Here we evaluate the evidence for martian global contraction using a recent compilation of thrust faults. Fault-related strains were calculated for wrinkle ridges and lobate scarps to provide lower and upper bounds, respectively, on the magnitude of global contraction from contractional structures observed on the surface of Mars. During the hypothesized pulse of global contraction, contractional strain of −0.007% to −0.13% is indicated by the structures, corresponding to decreases in planetary radius of 112 m to 2.24 km, respectively. By contrast, consideration of all recognized thrust faults regardless of age produces a globally averaged contractional strain of −0.011% to −0.22%, corresponding to a radius decrease of 188 m to 3.77 km since the Early Noachian. The amount of global contraction predicted by thermal models is larger than what is recorded by the faults at the surface, paralleling similar studies for Mercury and the Moon, which suggests that observations of fault populations at the surface may provide tighter bounds on planetary thermal evolution than models alone. |
| Keywords: | Tectonics Thermal histories Mars Surface |
| 本文献已被 ScienceDirect 等数据库收录！ | |