Abstract Rock properties are a crucial control of landform development. The purpose of this chapter is to examine the progress that was made in studying rock properties in general and then to discuss developments in the study of landforms in three main rock types: granite, limestone and sandstone. From the mid-1960s onwards, geomorphology witnessed an increasing concern with the quantification of rock properties and their relationship to landforms and landscape evolution. Japanese geomorphologists led in this endeavour. Studies crossed a range of scales from those of a large size that were susceptible to field measurements to those of small size that involved laboratory studies. Among the basic characteristics of rocks that have been studied are fracturing and jointing, rock mass strength, hardness as determined by the Schmidt Hammer, resistance as determined by laboratory simulations, slaking susceptibility, porosity, water absorption capacity, water content and permeability, and petrological thin-section analyses. The investigation of forms and processes in granite, limestone and sandstone areas has shown the value of combined geological and geographical approaches, and the increasing internationalization of studies.

North American research on surface karst landforms has tended to focus on factors affecting the development and distribution of sinkholes. There have been important quantitative contributions to understanding the formation of solutional, suffosional, and collapse sinks, and a major series of applied geotechnical studies has been published. Gypsum karst, and the impacts of repeated glaciations and permafrost on carbonate, gypsum, and salt karst have received much attention in recent years. North American research dominated the general field of speleogenesis until the past two decades. There are well-understood models for dissolutional cave development in young, newly emerged limestones, for situations where cool or thermal waters ascend from deeper formations, and for descending, unconfined meteoric waters. Worldwide, there is now intensive computer modeling of conduit initiation and enlargement and their relation to the evolution of karst aquifers. There have been many important advances in the study of cave deposits. Clastic sediments may be dated approximately by paleomagnetics, more precisely by cosmogenic 10 Be/ 26 Al decay of quartz sands or pebbles, and by 39 Ar/ 40 Ar where clays have been converted to alunite by H 2 S reactions. Currently, there is a bandwagon in paleoenvironmental studies of speleothems. They can be precisely dated back to 500,000 yr B.P. by U-series methods, their C and O isotope ratios track local and regional environmental changes over the course of the glacial cycles, and many display annual or other significant periodic banding.

Abstract Studies of the paleomagnetism and rock magnetism of speleothems have shown that their natural remanent magnetizations (NRMs) are either detrital remanent magnetizations (DRMs), chemical remanent magnetizations (CRMs), or a mixture of both. The DRM arises from magnetic particles deposited by cave floods, and the evidence is unequivocal. The CRM results from organic-chelated iron or bacteria, and the evidence is circumstantial. The frequent presence of organic materials in speleothems is easily demonstrated, and they may be soluble, insoluble, or both. Organics account for the color of many speleothems. Whether the remanence is DRM or CRM, the signal is contemporaneous with the precipitation of the host calcite matrix and is measurably free of depositional inclination error effects. It is suggested that the studies summarized here have relevance for the timing of remanence in diagenetic limestone calcite, faithfulness of this remanence in its alignment along the ambient magnetic field at the site, and to hydrocarbon-magnetite associations in carbonate rocks.

Abstract Karst landscapes are the foremost examples of ground-water erosion on this planet. The sculpturing and removal of bedrock is predominantly by solution, aided in some cases by soil piping and collapse. Karst landforms develop best in limestones and dolomites, gypsum, and salt. Carbonate rocks crop out over approximately 10 p.rcent of the earth’s land area and are found in most nations and all climatic regions. It is estimated that 25 p.rcent of the world's population depends on fresh water in karst aquifers. Karst rocks and their contained minerals, oil, and gas are of considerable importance to the extractive industries, while caves and other karst features have been of great cultural significance. Karst aquifers are the mavericks of hydrogeology. Closed depressions input a recharge that is intermediate between the classic ideas of infiltration and surface runoff. Integrated conduit systems act as short circuits for the ground-water flow system. Conduits are gross heterogeneities in the permeability distribution, and flow within them does not obey Darcy’s Law. The purpose of this chapter is to outline some of the geomorphic features of karst areas and to indicate their relationship to karstic aquifers. Recent English language books on karst studies include Sweeting (1972), Ford and Cullingford (1976), Bögli (1980), Milanović (1981), Jennings (1985), James and Choquette (1988), and White (1988).