Turbidité, indicateur du fonctionnement perturbé du géosystème karstique de l’Atlas de Beni Mellal (Moyen Atlas méridional, Maroc), 2002, Elkhalki Yahia, Hafid Abdellatif

Turbidity, as an indicator of perturbed functioning of karst geosystem of Beni Mellal Atlas (Southern Middle Atlas, Morocco) - The turbidity of karst springs is a general phenomenon of anthropized Mediterranean limestone mountains. But actually we note that it has been somewhat neglected by karstologists. In other respects, it represents a pertinent indicator of the dysfunctioning of karst geosystems which have undergone a strong impact of human action. Cloudy waters distinguish Asserdoune spring, as the main outlet of Liassic aquifer. After dry periods, followed by brutal storms, water turbidity can exceed 2000 JTU (Jackson Turbidity Unit). Three factors are united to favour the turbidity water: 1) The climate: autumn rain storms which follow a long dry season, fall on soils that are dry and badly protected by vegetation. They cause an important mobilisation of fine particles, which infiltrate the epikarst.2) Inner karst structure: the advance of cloudy water toward Aïn Asserdoune spring is made easier by developed drains. Dye tracings have shown that the time of transit waters is comprised between 24 and 72 hours.3) Human impact: the agriculture modernisation of Tadla plain (140 000 ha irrigated) was accompanied with a violent action on forest resources of Beni Mellal Atlas. Clearings induced a large stripping of soils, which caused the excavation of covered karrens. Furthermore, the dysfunctioning of the karst geosystem of Beni Mellal Atlas is translated by the hindrance of present travertinisation at the downstream of springs.

Principles of protection of karst areas, 2008, Andrejchouk V. N. , Stefanov P.

Karst objects are characterised by high attractivity and often protected by low. However, the experience of their protection shows that in spite of high nature-protected status their progressive degradation often takes place. One of the reasons for this is that natural specifics of karst objects and areas is not taken into account. It is that karst process is a system-forming one, which organise (according to given regularities) the environment of its development and forms territorially unified and functionally whole formations – karst geosystems (KGS). KGS have a specific structure both in the vertical aspect (levels of interacting components: surface landscape↔underground cavities) and the horizontal aspect (paradynamic connection of karst features such as: doline↔catchment area etc.). The first principle of protection of karst objects and areas is based on the fact of vertical interaction of KGS parts: it is inadequate to protect separately underground or(and) surface parts of KGS. The fact of close lateral matter-energy connections of KGS parts tells us that it is necessary to take into account the horizontal functional links between KGS elements when establishing surface limits of protected objects or areas. Also extention of surface protected part have to correspond not only to the size of geotop (i.e. just karst  feature) but include also its paradynamic (paragenetic) surroundings. This is a second basic principle of protection of karst objects and areas. Both principles follow directly from the system-organizing nature of karst.

On the essence of karst, 2010, Klimchouk, O. B. , Andreychouk, V. N.

The long-lasting uncertainty with the central for karstology notion of karst hinders synthesis of knowledge and the development of a theoretical basis of this scientific discipline. This paper analyses the essence of karst, based on generalization of the modern ideas about regularities of the origin and evolution of conduit permeability in soluble rocks, viewed in the light of ideas of synergetics and non-equilibrium thermodynamics of I.P.Prigogine regarding self-organization in open systems and formation of ordered dissipative structures.

The presence of soluble rocks in the sedimentary environment determines a phenomena of self-organization of the flow structure, which brings the water-rock system into a new capacity-state, namely – karstic.  The property of self-organization of this geosystem realizes via specific (speleogenetic) mechanism of permeability development, which action radically changes (organizes in a special manner) the structure and functioning of the flow system.

The mechanism of self-organization of flow and of the formation of the karst geosystem (speleogenesis) includes: 1) early speleogenesis, positive feedback between flow and the rate of enlargement of initial flow paths (revealing of proto-conduits), 2) speleogenetic initiation: a cascade breakthroughs of proto-conduits to the condition of rapid dissolution kinetics, with accelerated growth of initiated conduits, hydrodynamic competition, respective destabilization and reorganization of the flow pattern and change in boundary conditions, and, 3) speleogenetic development: stabilization of the system at dynamic equilibrium at the expense of increased energy exchange with the environment, and further growth of conduits. As a result of this specific evolution the geosystem acquires ànew, «karstic», capacity and more complex of organization, with the establishment of one more level of permeability, the most contrast one.

The notion of karst is derived from the essence of progressive evolution of the geosystem containing permeable soluble rocks, driven by water exchange and speleogenetic mechanism of self-organization of the permeability structure. Regressive evolution of the karst geosystem includes processes of gravitational destruction and various accumulations, which lead to fragmentation and demolition of relict structures of karst permeability. Based on this new approach to definition of the notion of karst, criteria of distinction between proper karst and similar but not identical phenomena (merokarst, pseudokarst) are discussed.

The karst paradigm: changes, trends and perspectives, 2015, Klimchouk, Alexander

The paper examines representative definitions of karst (21), and discusses some concepts that influenced the modern un­derstanding of the phenomenon. Several trends are discussed that took karst science beyond the limits of the traditional par­adigm of karst. Dramatic progress in studies of speleogenesis plays the most significant role in changes taking place in the general understanding of karst. Also important is an adoption of the broad perspective to karst evolution which goes beyond the contemporary geomorphologic epoch and encompasses the entire life of a geological formation. Speleogenesis is viewed as a dynamic hydrogeological process of self-organization of the permeability structure in soluble rocks, a mechanism of the specific evolution of the groundwater flow system. The result is that these systems acquire a new, "karstic", quality and more complex organization. Since almost all essential attributes of karst owe their origin to speleogenesis, the latter is considered as the primary mechanism of the formation of karst. Two fundamental types of speleogenesis, hypogene and epigene, differentiate mainly due to distinct hydrodynamic characteristics of the respective groundwater flow systems: (1) of layered aquifer systems and fracture-vein flow systems of varying depths and degrees of confinement, and (2) of hydrodynamically open, near-surface unconfined systems. Accordingly, two major genetic types of karst are distinguished: hypogene and epigene. They differ in many characteristics, notably in relationships with the surface, hydrogeological behaviour, groundwater quality, and the areas of practical importance and approaches to solving karst-related issues. Although views on essential attributes of karst have been clearly changing, this was not reflected in definitions of the notion which are in broad use in the earth-science literature. A refined approach is suggested to the notion of karst in which it is viewed as a groundwater (fluid) flow system of a specific kind, which has acquired its peculiar properties in the course of speleogenesis.