Global Geomorphology

Any global view of landforms must include an evaluation of the link between plate tectonics and geomorphology. To explain the broad features of the continents and ocean floors, a basic distinction between the tectogene and cratogene part of the Earth's surface must be made. The tectogene areas are those that are dominated by crustal movements, earthquakes and volcanicity at the present time and are essentially those of the great mountain belts and mid ocean ridges. Cratogene areas comprise the plate interiors, especially the old lands of Gondwanaland and Laurasia. Fundamental as this division between plate margin areas and plate interiors is, it cannot be said to be a simple case of a distinction between tectonically active and stable areas. Indeed, in terms of megageomorphology, former plate margins and tectonic activity up to 600 million years ago have to be considered

Geomorphology of Mountainous Deserts

The peculiar land forms of the desert are due largely (1) to the paucity of plant growth, in consequence of which (2) disintegrated rock, produced more by physical than by chemical processes, which (3) vary with rock nature (hence granitic rocks assume forms of special interest), does not remain near its source long enough in the earlier stages of erosion to be reduced to very fine texture before (4) it is carried by stream floods or sheet floods toward or to (5) playa basins of rising base-level; but in an advanced stage of the arid cycle (6) the playa surface may be lowered by the wind, whereupon the rock slopes previously weathered down to sheet-flood grade and buried with sheet-flood waste will be (7) trenched by stream floods with respect to the sinking baselevel, and the buried rock floors will be laid bare until again reduced to sheet-flood grade. But (8) in deserts draining to the ocean these various processes will work with respect to a relatively fixed baselevel; also (9) in deserts where the action of water floods is dominated by wind action, the carving of the surface will be in part independent of any baselevel

Geomorphology of the Kaikoura area

The major physiographic units in the Kaikoura area are the Peninsula Block, Beach Ridges and Raised Beaches, Hard Rock Areas and the Alluvial Fans. Erosion of the Seaward Kaikoura Mountains and the transfer of the debris to the sea by fan streams have contributed to coastline pro gradation so that a former offshore island, now called the Kaikoura Peninsula, has been joined to the mainland. On the piedmont alluvial plain between the mountains and the sea Otiran Glacial Stage and Holocene fan deposits have covered up older fan surfaces. Stillstands during the tectonic uplift of the Peninsula Block when marine processes cut shore platforms and also higher stands of interglacial sea levels in the Late Pleistocene have contributed to the development of erosion surfaces. Along the coast beach ridges and raised beaches have developed during post-glacial times

Geomorphology, tectonics, and exploration

Explorationists interpret satellite images for tectonic features and patterns that may be clues to mineral and energy deposits. The tectonic features of interest range in scale from regional (sedimentary basins, fold belts) to local (faults, fractures) and are generally expressed as geomorphic features in remote sensing images. Explorationists typically employ classic concepts of geomorphology and landform analysis for their interpretations, which leads to the question - Are there new and evolving concepts in geomorphology that may be applicable to tectonic analyses of images

Lava tubes of the cave basalt, Mount Saint Helens, Washington

Geomorphology of basaltic lava tubes from Mount St. Helens, Washingto

A New Global Geomorphology?

Geomorphology is entering a new era of discovery and scientific excitement centered on expanding scales of concern in both time and space. The catalysts for this development include technological advances in global remote sensing systems, mathematical modeling, and the dating of geomorphic surfaces and processes. Even more important are new scientific questions centered on comparative planetary geomorphology, the interaction of tectonism with landscapes, the dynamics of late Cenozoic climatic changes, the influence of cataclysmic processes, the recognition of extremely ancient landforms, and the history of the world's hydrologic systems. These questions all involve feedback relationships with allied sciences that have recently yielded profound developments

Mega-geomorphology and neotectonics

For several decades, subtle neotectonic effects involving several square kilometers have been studied in detail using remote sensing, primarily various types of stereo-aerial photographs at scales of 1:10,000 to 1:80,000. These subtle effects, especially local uplifts associated with growing structures of differential compaction, have been detected by the effect on drainage patterns, changes in hydraulic geometry of individuals channels or groups of channels, tonal halos (soil) and fracture patterns. The studies were extended with the advent of thermal IR imagery particularly in tonal analysis, and SLAR primarily in fracture pattern studies. Lately, quantitative efforts have begun attempting to link measured uplift over known structures with measured changes in hydraulic geometry and alluvial deposition. Thus, efforts are now underway attempting to quantify the relationship between neo- (micro-) tectonic changes and geomorphic parameters of drainage systems

The Channeled Scabland

The geomorphology and hydrodynamics of high velocity flood erosion in the channeled scabland of the Columbia Basin are discussed

Géomorphologie : géographie globale – géographie totale – associations internationales

The great advances that geomorphology has made in recent years make necessary a critical re-examination of the relationships between this science and the field of geography. Is geomorphology truly geographical ? And if not, how can it become so ?Geomorphology has its roots in geology and was, of course, not designed to meet the specific needs of geographers. Under the leadership of W. M. Davis, geographers eventually adopted the study of geomorphology but did Utile to adapt it to particular purposes of their discipline. Most geographers can never aspire to true excellence in geomorphology because of their generally inadequate training in the physical sciences. We have found that most geographers tend to fall into one of four groups : 1. Those who consider themselves to be geomorphologists (about one-fourth of all geographers) ;2. Those who just try to be informed in geomorphology ;3. Those who ignore the existence of geomorphology ;4. The « complete » geographer who practices a « functional » geomorphology. It also appears that the majority of geographers do not consider land-man relations to be their principal field of interest. The definition that we as geographers give to geography tends to sanction the kind of geography that we are capable of doing. For example, the classical géographie globale, which is characterized by an explanatory description of a complex of physical and human eclectic elements, does not normally require either a « complete » or a genetic geomorphology ; also, complex techniques of geomorphological investigation are not essential. Of greater importance is a geomorphology'-which is functional to geography and which will help us to understand better man's distribution and activities on the surface of the earth. This partial or « functional » geomorphology has achieved its greatest development in France (as an integral part of géographie globale) and is practised by a large number of geographers. Géographie totale, an expression which refers more to the subject matter of this geography than to its methodology, is an ensemble of specialized yet inter-related disciplines (one of which is geomorphology). This pluralistic geography daims many more adherents than does géographie globale. Géographie totale allows us to study all aspects of what is now called geomorphology (but which may eventually be termed « cosmomorphology  »). This new geomorphology is based on geophysical laws and is strictly quantitative. It is an integral part of the physical sciences but this does not mean that it is automatically divorced from man. Scientists of both the United States and the U. S. S. R. are actively engaged in this new geomorphology. We believe that it would be mutually advantageous for both the « functional » and the « complete » geomorphologists to group themselves into a new international association. To achieve this end we urge that the structures of the international Geographical Union be modified or that an « International Association of Geomorphology » be founded