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Phreatomagmatic explosive origin of Hrad Vallis , Mars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Wilson, Lionel Mouginis-Mark, Peter J. |
| Copyright Year | 2003 |
| Abstract | [1] Hrad Vallis is a 370 m deep, 800 km long depression located at 34 N, 218 W, in Elysium Planitia, Mars. A distinctive deposit, present on both sides of the source area of Hrad Vallis, has a maximum width of 70 km along the strike of the depression, a lower unit extends for nearly 100 km away from the depression on either side, and an upper unit extends for 50 km. Viking and Mars Orbiter Camera (MOC) images show lobate deposit boundaries, rheomorphic deformation, and numerous craters 270–580 m in diameter within the deposit. The deposit coincides with a broad topographic rise 30 km wide and 100–150m high extending along the sides of the valley for at least 100 km along strike. We propose that these features formed when a dike underlying the axis of the valley generated a shallow sill, which in turn is partly responsible for the rise topography. The remainder of the rise consists of a mud-like deposit of ejecta from a large-scale phreatomagmatic explosion due to violent mechanical and thermal mixing between the central part of the sill and ice-rich rock layers in the upper few hundred meters of the crust in a fuel-coolant-type interaction. The observed range and thickness of ejecta and the depth of the Hrad depression imply explosion steam pressures up to 360 MPa, ejecta speeds of 400 m s , and a sill at least 150 m thick intruded at a depth of 350– 400 m below the original surface. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.higp.hawaii.edu/~pmm/Wilson_MM_Hrad_JGR.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 3-Mercaptopropionic Acid Apache Axis Axis vertebra Cineraria vallis-pacis Depressive disorder Diameter (qualifier value) Hymenodontopsis vallis-gratiae Scab Thickness (graph theory) Topography Vitreous chamber of eyeball anatomical layer width |
| Content Type | Text |
| Resource Type | Article |
