Planetary landscape systems: a limitless frontier

Abstract

If it is to be a complete science of landforms and landscapes, geomorphology is not appropriately limited geographically to the terrestrial portions of Earth's surface. Various systems of landforms and their generative processes are best understood in a full planetary context. Moreover, by extending its purview to include the nature of landscapes on Earth-like planets, geomorphological inquiry is not appropriately limited in its philosophical presumptions to the reductionist views that have so successfully guided much of physics. Holistic thinking, exemplified by some aspects of evolutionary biology, and a systems framework may prove to be particularly fruitful for understanding future extraterrestrial discoveries and the general nature of landforms and landscapes. Figure 1. Incised meanders and inset channel of Nanedi Vallis, Mars (Latitude 5·2°N, Longitude 311·8°E). This image from the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter shows a scene 6 km wide.discovery (Baker et al., 1992). Here, another important aspect of analogical reasoning comes into play. If we provisionally accept an analogy as true, then we must infer what would be expected in a planetary system that would be consistent with that presumption. Obviously, we then need to see if the expected associations are indeed present. For an aqueous origin of Venus channels to be reasonable we would expect many other water-related landforms to be present on Venus. However, Venus is dominated by volcanic landforms; there are no associated water-related landforms, other than the channels, all of which exist in volcanic contexts. Figure 2. Lobate debris apron (relict, debris-covered glacial lobe) in Deuteronilus Mensae, Mars (Latitude 39·8°N, Longitude 23·1°E). This HiRISE image shows a scene 6 km wide. Glacial flow features (Kargel, 2004) indicate ice movement converging at the top of the scene (north) and extending toward the lower left, and terminating in a lobate flow front. Profiles for similar lobate debris aprons are consistent with solid state deformation of ice up to a few hundred metres thick (Mangold and Allemand, 2001).Figure 3.Dendritic network on Titan revealed on a mosaic of three images acquired by the Huygens Descent Imager. The width of the imaged scene is approximately 6·5 km. The scene has been stretched to enhance the contrast between the relatively dark channels and the brighter upland terrains into which they are incised.

Introduction to the special issue: Planetary geomorphology

“…And surface investigations (also listed in Table 1) are enhancing these orbital data with outcrop-type information, critical to constraining geomorphic processes. Publications from the Mars Exploration Rover missions and most recently from the Mars Science Laboratory (Curiosity) show numerous examples of planetary surface data providing constraints on impact, aeolian, fluvial, and lacustrine processes (Arvidson et al, 2011;Hayes et al, 2011;Squyres et al, 2012;Williams et al, 2013).…”

“…Traveling to and gaining information from planetary bodies beyond Earth are the newest endeavor in this exploration of landscapes (Baker, 2008). As the science of geomorphology continues to benefit from analyses of terrestrial landscapes under different climatic, lithologic, and tectonic conditions, so the analysis of extraterrestrial landscapes under different gravitational regimes, crustal and sedimentary compositions, and geophysical forcing mechanisms expands our understanding of geomorphologic processes (Baker, 2012).…”

The cryosphere and glacial permafrost as its integral component

“…A stand on geomorphology, as complementary to the proposed rule of Spatial Uniformitarianism, such as has been formulated for planetary landscape systems, is presented by Victor R. Baker in his impressive work [9]. I will take the liberty of quoting one of the conclusions: " …”

Palaeohydrology: the past as a basis for understanding the present and predicting the future.

“…Though it may be many decades before adequate resolution is achieved to analyze surface details on the immense number of potential planets on which to pursue future geomorphology, the science of earthlike planetary surfaces (Baker, 2008c) will continue to be focused on Earth's surface and that of nearby neighbors, particularly Mars. Its scientific scope will involve both the range of landscape phenomena to be studied and also the range of approaches that will be taken in that study.…”