Title of article :
New observations of Warrego Valles, Mars: Evidence for precipitation and surface runoff
Author/Authors :
Ansan، نويسنده , , V. and Mangold، نويسنده , , N.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2006
Pages :
24
From page :
219
To page :
242
Abstract :
Most valley networks have been identified primarily in the heavily cratered uplands which are Noachian in age (>3.5 Gyr). A striking exception to this general observation is Warrego Valles located on the southeastern part of the Tharsis bulge. Recent data obtained by the Mars Orbiter Laser Altimeter, the Thermal Emission Imaging System (THEMIS) spectrometer and the Mars Orbiter Camera give new insight into the formation of valley networks and the early Mars climate. We focus our study on the southern Thaumasia region especially on Warrego Valles and determine the organisation of valleys in relation to regional topography and structural geology. Warrego Valles is the most mature valley network that incised the southern side of Thaumasia highlands. It developed in a rectangular-shaped, concave-up drainage basin. Four times more valleys are identified in THEMIS infrared images than in Viking images. Valleys exist on both sides of the main tributary contrary to what was visible in Viking images. Their distribution is highly controlled by topographic slope, e.g. there is a parallel pattern on the sides and dendritic pattern on the central part of Warrego Valles. We quantitatively analyse valley morphology and morphometry to determine the processes responsible for valley network formation. Warrego Valles displays morphometric properties similar to those of a terrestrial fluvial valley network. This valley network is characterised by seven Strahlerʹs orders, a bifurcation ratio of 3, a length ratio of 1.7, a drainage density of 0.53 km−1 and a ruggedness number of 3.3. The hypsometric curve and integral (0.46) indicate that Warrego Valles reached the mature Davis’ stage. Valleys have undergone external degradation since their incision, which masks their main morphological characteristics. Our study supports the assertion that valley networks formed by fluvial processes controlled by an atmospheric water cycle. Further, they seem to develop by successive stages of erosion that occurred during Noachian through the late Hesperian.
Keywords :
Warrego Valles , Mars , water , Fluvial process , Noachian–Hesperian , Valley network
Journal title :
PLANETARY AND SPACE SCIENCE
Serial Year :
2006
Journal title :
PLANETARY AND SPACE SCIENCE
Record number :
2312566
Link To Document :
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