Formation of gravel pavements during fluvial erosion as an explanation for persistence of ancient cratered terrain on Titan and Mars

Howard, A. D.; Breton, Sylvain; Moore, Jeffrey M.

doi:10.1016/j.icarus.2015.05.034

Cited by 21 publications

(10 citation statements)

References 105 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our result is consistent with a warm and wet early Mars climate and the existence of an ancient northern ocean. If erosion of the VNs required significant chemical or physical weathering to produce transportable sediment, fluvial abrasion of channel beds 33 or transport of appreciable quantities of gravel 34 , the required volume of water may have been many times our conservative estimate.…”

Section: Discussionmentioning

confidence: 99%

New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate

2017

Self Cite

View full text Add to dashboard Cite

The volume of Martian valley network (VN) cavity and the amount of water needed to create the cavity by erosion are of significant importance for understanding the early Martian climate, the style and rate of hydrologic cycling, and the possibility of an ancient ocean. However, previous attempts at estimating these two quantities were based on selected valleys or at local sites using crude estimates of VN length, width and depth. Here we employed an innovative progressive black top hat transformation method to estimate them on a global scale based on the depth of each valley pixel. The conservative estimate of the minimum global VN volume is 1.74 × 1014 m3 and minimum cumulative volume of water required is 6.86 × 1017 m3 (or ∼5 km of global equivalent layer, GEL). Both are much larger than previous estimates and are consistent with an early warm and wet climate with active hydrologic cycling involving an ocean.

show abstract

Section: Discussionmentioning

confidence: 99%

New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate

2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our interpolated topography can now be used to understand surface‐atmosphere interactions, surface transport processes, and geophysical processes. This data set can also be used as an input to various models that will attempt to understand these processes and interactions on Titan (e.g., Howard et al, ; Neish et al, ). Below, we provide an initial qualitative overview of the new features in the topographic data.…”

Section: Discussionmentioning

confidence: 99%

Titan's Topography and Shape at the End of the Cassini Mission

Corlies

Hayes

Birch

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

With the conclusion of the Cassini mission, we present an updated topographic map of Titan, including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets available from the mission. We use radial basis functions to interpolate the sparse data set, which covers only ∼9% of Titan's global area. The most notable updates to the topography include higher coverage of the poles of Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We also present a statistical analysis of the error in the derived products and perform a global minimization on a profile‐by‐profile basis to account for observed biases in the input data set. We find a greater flattening of Titan than measured, additional topographic rises in Titan's southern hemisphere and better constrain the possible locations of past and present liquids on Titan's surface.

show abstract

“…The MARSSIM landscape evolution model is composed of various submodels of geomorphic processes and impact cratering interacting to produce realistic simulated landscapes. Planetary applications of the MARSSIM landscape evolution model include studies of Martian valley networks (Barnhart et al, ; Luo & Howard, ); the interaction of impact cratering with fluvial erosion (Howard, ); and sublimation‐driven landform degradation on Callisto, Hyperion, and Titan (Howard & Moore, ; Howard et al, , ).…”

Section: Methodsmentioning

confidence: 99%

“…We estimated the sediment transport flux in alluvial channels using a bed load transport formula expressed as the relationship between a dimensionless rate of transport, Ф, and a dimensionless shear stress, τ * :

normalΦ = K_{e} {\{τ^{*} - τ_{c}^{*}\}}^{p},

where

normalΦ = \frac{q_{sb} ((), 1 - μ)}{g^{1 / 2} d^{3 / 2}} and τ^{*} = \frac{τ}{ρ_{f} g ((), S_{s} - 1) d}

τ * c is the dimensionless shear stress at the threshold of motion ( τ * c = 0.05), q sb is the rate of bed sediment transport in bulk volume of sediment per unit time per unit channel width (m 3 m −1 s −1 ), S s is the specific gravity of the sediment ( S s = 2.65), d is the sediment grain size (m), and μ is alluvium porosity ( μ = 0.5). Fluvial transport using an assumed range of source sediment grain sizes can be simulated (e.g., Howard et al, ), but such simulations are computationally expensive and, given our lack of information on sediment sizes in the Martian fluvial system, not feasible.…”

Section: Methodsmentioning

confidence: 99%

Constraints on the Noachian Paleoclimate of the Martian Highlands From Landscape Evolution Modeling

2018

Self Cite

View full text Add to dashboard Cite

The progressive degradation and loss of impact craters throughout the Noachian Period on Mars indicate prolonged erosion, rather than only a brief spike around the Noachian/Hesperian transition. The purpose of this study is to determine which suite(s) of geomorphic processes and rates best reproduce the relict Noachian landscape. We modeled the evolution of two study areas in the Martian highlands, Noachis Terra and Terra Cimmeria, to constrain the long-term erosional processes and rates that prevailed~4.0-3.7 Ga, before the valley networks formed. Our model runs indicate a very low erosion rate and inefficient runoff production during the Middle and Late Noachian Epochs. The terrestrial equivalent of 2 and 1.5 Myr worth of erosional work under arid to semiarid conditions with inefficient runoff production was required in order to replicate the landscape at Noachis Terra and Terra Cimmeria, respectively, over~300 Myr. Low areas in the landscape filled with sediments, while mass wasting and fluvial erosion were focused on crater rims and interior walls. The surface characteristics that best reproduce the observed landscape are a bedrock weathering rate around 0.0005-0.001 m/year with regolith that is 100 times more erodible than bedrock, suggesting that impact comminution and aqueous weathering produced abundant transportable material on Noachian Mars. The simulation results suggest that the Noachian paleoclimate was more arid than around the Noachian/Hesperian transition, but it supported occasional precipitation (snow or rain) that weathered surface materials and transported sediments.Plain Language Summary Evidence shows that Mars was once wetter with liquid water flowing long enough on the surface to form valley networks. Previous studies indicate that the climate responsible for valley formation was short lived, although older craters are much more degraded than can be explained by short-term climate change. A landscape evolution model was used to recreate the landforms we see at two locations on Mars, Noachis Terra and Terra Cimmeria, to estimate the possible climatic conditions responsible for shaping the topography of early Mars before the formation of valley networks (~4.0-3.7 Ga). We controlled parameters such as aridity, the weathering rate of the surface material, and how much of the precipitation contributes to surface runoff. Our model runs indicate conditions similar to those of arid to semiarid environments on Earth with a very low erosion rate and inefficient runoff during the Middle and Late Noachian Epochs. Our results also show that crater impacts and aqueous weathering produced abundant loose materials that are transportable by surface flow. A major portion of early Mars was more arid than around the time of intense valley formation, but it supported occasional precipitation (snow or rain) that weathered and transported surface sediments. Howard et al., 2005; Irwin et al., 2015; Moore & Howard, 2005). A longer-term wet climate likely would result in MATSUBARA ET AL. 2958

show abstract

Formation of gravel pavements during fluvial erosion as an explanation for persistence of ancient cratered terrain on Titan and Mars

Cited by 21 publications

References 105 publications

New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate

New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate

Titan's Topography and Shape at the End of the Cassini Mission

Constraints on the Noachian Paleoclimate of the Martian Highlands From Landscape Evolution Modeling

Contact Info

Product

Resources

About