scholarly journals Comparitive Study of the Geomorphological Characteristics of Valley Networks between Mars and the Qaidam Basin

2021 ◽  
Vol 13 (21) ◽  
pp. 4471
Author(s):  
Lu Chen ◽  
Yi Xu ◽  
Bo Li
Keyword(s):  
Liquid Water ◽  
Qaidam Basin ◽  
River System ◽  
River Networks ◽  
Martian Surface ◽  
The Past ◽  
Branching Angle ◽  
Valley Networks ◽  
Valley Network

The complex valley networks that cross the Martian surface offer geomorphologic evidence of the presence of liquid water at some point in its history. However, the derivation of both temporal and hydrological dimensions of this climate phase is far from settled. Studies comparing terrestrial fluvial networks of known formation environments with those on Mars can be used as a key to unlock the past. This work represents an analogy study and comparison between the river networks in the Qaidam Basin and those on Mars. As the Martian valley networks formed in different geologic periods with characteristic and unique features, three cases from the Noachian to the Amazonian were selected to be compared with streams in the Mangya area, where the climate is extremely arid. In terms of the maturity of the dendritic river system, shape, concave index, and branching angle (BA), the valley network in the Mangya area is comparable to Naktong Vallis, dated to the Hesperian. We also calculated throughout the valley networks on Mars the parameters of the BA and the concave index, both of which are important climatic indicators. The results show that the climate on Mars became progressively more arid, starting from the Noachian up to the Amazonian.

Combination between Ca, P and Y in the Martian Meteorite NWA 6963 could be used as a strategy to indicate liquid water reservoirs on ancient Mars?

2018 ◽  
Vol 18 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Bruno Leonardo do Nascimento-Dias
Keyword(s):  
Liquid Water ◽  
Hydrothermal Fluids ◽  
Martian Surface ◽  
X Ray ◽  
Geological Characteristics ◽  
The Past ◽  
Northwest Africa ◽  
Aqueous Environments ◽  
Martian Meteorites ◽  
History Of

AbstractAlthough we have learned much about the geological characteristics and history of Mars, the gaps in our knowledge certainly exceed what we understand. Martian meteorites, such as Northwest Africa (NWA) 6963, can be excellent materials for understanding the present and past of Mars, as part of the records of the planet's evolution is preserved in these extraterrestrial rocks. Micro X-ray fluorescence provided data, in which it was possible to verify the presence of Ca, P and Y elements, which are call attention because they were detected superimposed in certain regions. The way these elements were detected indicates the formation of minerals composed by the combination of these elements, such as, for example, Calcite (CaCO3), Apatite [Ca5(PO4)3(OH, F, Cl)], Merrilite [Ca9NaMg (PO4)7] and Xenotime (YPO4). These minerals are great indicators of aqueous environments. In general, the formation of these minerals is due to processes involving hydrothermal fluids or sources (>100 °C). Some geological indications suggest that in the past there might have been a large amount of liquid water, which could have accumulated large reservoirs below the Martian surface. Thus, the laboratory study of Martian meteorites and interpretations of minerals present in these samples can contribute in a complementary way to the existing results of telescopic observations and/or missions of space probes as a strategy to indicate reservoirs of liquid water.

scholarly journals A new vector-based global river network dataset accounting for variable drainage density

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peirong Lin ◽  
Ming Pan ◽  
Eric F. Wood ◽  
Dai Yamazaki ◽  
George H. Allen
Keyword(s):  
Spatial Variability ◽  
Flow Direction ◽  
River System ◽  
Drainage Density ◽  
River Network ◽  
River Networks ◽  
Digital Elevation ◽  
Machine Learning Approach ◽  
Elevation Model ◽  
National Hydrography Dataset

AbstractSpatial variability of river network drainage density (Dd) is a key feature of river systems, yet few existing global hydrography datasets have properly accounted for it. Here, we present a new vector-based global hydrography that reasonably estimates the spatial variability of Dd worldwide. It is built by delineating channels from the latest 90-m Multi-Error-Removed Improved Terrain (MERIT) digital elevation model and flow direction/accumulation. A machine learning approach is developed to estimate Dd based on the global watershed-level climatic, topographic, hydrologic, and geologic conditions, where relationships between hydroclimate factors and Dd are trained using the high-quality National Hydrography Dataset Plus (NHDPlusV2) data. By benchmarking our dataset against HydroSHEDS and several regional hydrography datasets, we show the new river flowlines are in much better agreement with Landsat-derived centerlines, and improved Dd patterns of river networks (totaling ~75 million kilometers in length) are obtained. Basins and estimates of intermittent stream fraction are also delineated to support water resources management. This new dataset (MERIT Hydro–Vector) should enable full global modeling of river system processes at fine spatial resolutions.

The Ecology and Management of Wood in World Rivers

2003 ◽  
Keyword(s):  
Spatial Patterns ◽  
General Framework ◽  
River System ◽  
Field Studies ◽  
Transport Processes ◽  
River Networks ◽  
Spatial And Temporal Patterns ◽  
History Of ◽  
World Rivers ◽  
Trapping Sites

<em>Abstract.</em>—A landscape perspective of wood in world rivers accounts for spatial and temporal patterns of sources of wood from streamside forests, processes of wood delivery to channels, transport of wood through river networks, and trapping sites of wood. Amounts of wood in a river system also depend on productivity of forests in source areas and decomposition rates. Collectively, these factors determine the amount and arrangement of individual pieces and accumulations of wood through a river network, which, in turn, affect ecological, geomorphic, social, and other features of rivers. Research to date deals with subsets of these components of wood in rivers, but there has been limited development of a general framework for wood in river networks. This chapter considers a framework for examining the arrangement of wood in river landscapes and how it may reflect the history of spatial patterns and timing of wood input and redistribution. Field studies provide examples of different spatial patterns and architectures of wood accumulations. Wood accumulations are shaped by input processes, trapping sites, and transport processes. Reaches in river networks may switch from wood patterns dominated by one set of controls to another because of gradual or abrupt input and redistribution. A framework for future studies and management includes interpretation of these different controls through time and over river networks.

River basin management, described for the example of the Emschergenossenschaft

2003 ◽  
Vol 47 (7-8) ◽  
pp. 141-147 ◽  
Author(s):  
H.-C. Baumgart ◽  
F. Sperling ◽  
J. Stemplewski
Keyword(s):  
Structural Changes ◽  
River System ◽  
Industrial Area ◽  
River Basin Management ◽  
Recent Time ◽  
Basin Management ◽  
Ruhr Area ◽  
The Past ◽  
Drainage Capacity ◽  
Private Effort

Considerable problems concerning drainage capacity made it necessary, at the beginning of the 20th Century, to make a joint public-private effort, because the existence of the Ruhr Area as an industrial location was endangered. By Prussian law a co-operative was established for wastewater and drainage-management of the entire Emscher river system. In the past the Emscher Association and the later founded Lippe Association have proved to be the best instrument to cope with the wastewater problems of a densely-populated industrial area. In recent time, the Emscher area is undergoing fundamental structural changes. To increase its attractiveness increased efforts are needed for a modernisation of the wastewater transport and treatment system. To deal with the various and complex tasks to reshape the Emscher system, the joint association again provides a highly efficient and competent instrument.

River discharge, sedimentation, and benthic environmental variations in Miramichi Inner Bay, New Brunswick

1983 ◽  
Vol 20 (3) ◽  
pp. 388-398 ◽  
Author(s):  
C. T. Schafer ◽  
J. N. Smith
Keyword(s):  
New Brunswick ◽  
River Discharge ◽  
River System ◽  
Circulation Pattern ◽  
Foraminiferal Assemblage ◽  
Cross Sectional ◽  
Tidal Circulation ◽  
The Past ◽  
Environmental Variations ◽  
Sequential Studies

Sequential studies of benthonic foraminifera in the Miramichi estuary, New Brunswick over a 12 year period indicate that a "transitional" foraminiferal assemblage, which defines a zone of interaction of river and open bay environmental factors, has developed in Miramichi Inner Bay since 1964. Abundance variations of the transitional foraminiferal indicator species Ammotium cassis relative to Miliammina fusca (upper estuarine indicator) and Elphidium excavatum forma clavata (marginal marine indicator) in short cores suggest that the regional extent of this transitional thanatotope in the western part of Miramichi Inner Bay has varied considerably during the past 80–100 years. These changes appear to be related to total annual river discharge variations, competence of the Miramichi River system, and. possibly, changes in the tidal circulation pattern of bay water. Tidal circulation may have been altered by the location and cross-sectional area of several channels that occur between the barrier islands on the seaward side of the bay.

scholarly journals The glacial geomorphology of the Antarctic ice sheet bed

2014 ◽  
Vol 26 (6) ◽  
pp. 724-741 ◽  
Author(s):  
Stewart S.R. Jamieson ◽  
Chris R. Stokes ◽  
Neil Ross ◽  
David M. Rippin ◽  
Robert G. Bingham ◽  
...  
Keyword(s):  
Large Scale ◽  
Landscape Evolution ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Glacial Erosion ◽  
Antarctic Ice Sheet ◽  
The Past ◽  
Valley Network ◽  
The Antarctic ◽  
Antarctic Ice Sheets

AbstractIn 1976, David Sugden and Brian John developed a classification for Antarctic landscapes of glacial erosion based upon exposed and eroded coastal topography, providing insight into the past glacial dynamics of the Antarctic ice sheets. We extend this classification to cover the continental interior of Antarctica by analysing the hypsometry of the subglacial landscape using a recently released dataset of bed topography (BEDMAP2). We used the existing classification as a basis for first developing a low-resolution description of landscape evolution under the ice sheet before building a more detailed classification of patterns of glacial erosion. Our key finding is that a more widespread distribution of ancient, preserved alpine landscapes may survive beneath the Antarctic ice sheets than has been previously recognized. Furthermore, the findings suggest that landscapes of selective erosion exist further inland than might be expected, and may reflect the presence of thinner, less extensive ice in the past. Much of the selective nature of erosion may be controlled by pre-glacial topography, and especially by the large-scale tectonic structure and fluvial valley network. The hypotheses of landscape evolution presented here can be tested by future surveys of the Antarctic ice sheet bed.

scholarly journals On the probability of habitable planets

2013 ◽  
Vol 12 (3) ◽  
pp. 177-185 ◽  
Author(s):  
François Forget
Keyword(s):  
Liquid Water ◽  
Climate Models ◽  
Climatic Conditions ◽  
Point Of View ◽  
Habitable Zone ◽  
One Dimensional ◽  
The Past ◽  
Surface Liquid ◽  
New Generation ◽  
Global Mean

AbstractIn the past 15 years, astronomers have revealed that a significant fraction of the stars should harbour planets and that it is likely that terrestrial planets are abundant in our galaxy. Among these planets, how many are habitable, i.e. suitable for life and its evolution? These questions have been discussed for years and we are slowly making progress. Liquid water remains the key criterion for habitability. It can exist in the interior of a variety of planetary bodies, but it is usually assumed that liquid water at the surface interacting with rocks and light is necessary for emergence of a life able to modify its environment and evolve. The first key issue is thus to understand the climatic conditions allowing surface liquid water assuming a suitable atmosphere. These have been studied with global mean one-dimensional (1D) models which have defined the ‘classical habitable zone’, the range of orbital distances within which worlds can maintain liquid water on their surfaces (Kasting et al. 1993). A new generation of 3D climate models based on universal equations and tested on bodies in the solar system are now available to explore with accuracy climate regimes that could locally allow liquid water. The second key issue is now to better understand the processes which control the composition and the evolution of the atmospheres of exoplanets, and in particular the geophysical feedbacks that seem to be necessary to maintain a continuously habitable climate. From that point of view, it is not impossible that the Earth's case may be special and uncommon.

scholarly journals Ice on Mars

1974 ◽  
Vol 13 (68) ◽  
pp. 173-185 ◽  
Author(s):  
Robert P. Sharp
Keyword(s):  
Liquid Water ◽  
Polar Regions ◽  
Martian Surface ◽  
Ground Ice ◽  
Water Ice ◽  
Small Areas ◽  
Ice Caps ◽  
The North ◽  
Patterned Structures ◽  
Water Substance

Ice unquestionably exists on Mars. Annual polar-region frost blankets are principally solid CO2, and perennial residual ice caps near each pole are probably water ice, except for a part of the north polar cap which may consist of a 1 km thick mass of solid CO2. Minor amounts of carbon-dioxide clathrate (CO2 · ≈ 6H2O) presumably accompany the solid CO2. The annual frost blankets may have a concentric banding with an outermost very thin layer of water frost, an intermediate narrow zone of clathrate, and a major central core of solid CO2. Layered deposits and underlying homogeneous materials mantle large areas within both polar regions. These blankets are probably composed of dust, volcanic ash, or both, and possibly contain frozen volatiles. They may comprise the largest reservoir of water substance on the Martian surface. Ground ice formed by the freezing of ascending de-gassed water substance may underlie the surface of Mars. Localized collapse of small areas may be due to ground-ice deterioration, and recession of steep slopes may have been caused by ground-ice sapping. If liquid water ever existed in significant quantities on the Martian surface, intense frost shattering, widespread creep, and prolific development of patterned structures should have occurred because the thermal regimen of the surface is highly favorable to the freeze–thaw process. It is ineffective at present owing to the lack of liquid water. No evidence suggests that the residual ice caps have ever acted like terrestrial glaciers in terms of erosion and deposition. Currently, they are too thin, too cold, and presumably frozen to their substrates. Their most important function is to buffer the atmosphere in terms of its H2O and CO2 content, thereby exerting a modifying influence on the surface environment of the entire planet.

scholarly journals Mars: Occurrence of liquid water

1971 ◽  
Vol 40 ◽  
pp. 247-250
Author(s):  
Andrew P. Ingersoll
Keyword(s):  
Liquid Water ◽  
Evaporation Rate ◽  
Heat Sources ◽  
Martian Surface ◽  
Concentrated Solutions ◽  
Water Condensation

In the absence of juvenile liquid water, condensation and subsequent melting of ice are the only means of producing liquid water on the Martian surface. However, the evaporation rate is so high that the available heat sources cannot melt ice on Mars. Melting might occur only in concentrated solutions of strongly deliquescent salts.

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