Wody szczelinowe kredy lubelskiej
Abstract
FISSURE WATERS IN THE CRETACEOUS IN THE LUBLIN REGION
Summary
The paper presents a hydrogeological model for the Lublin Cretaceous. The massif built of carbonate rocks displays dense and relatively regular network of fissures. The most important fissures, i.e. those bearing decisive influence on circulation and accumulation of waters, are supracapillary ones (over 0.25 mm in width), related to orthogonal joint system. In turn, intensity of flow appears controlled by fissures which accompany dislocation zones cutting the massif. The latter form concentrated flows as they drain water flowing in dispersed way in a network of minor fissures. The width and depth range of water-bearing fissures depends on lithological development and mechanic properties of rocks, especially their strength to compression and susceptibility to swelling. The above mentioned features of the massif are responsible for vertical and lateral zonation in its hydrogeological properties.
Despite of the above mentioned zonal differentiation of properties, Upper Cretaceous rocks form a single aquifer with hydraulic connections. Waters present in this aquifer are mainly related to direct percolation of precipitation water or percolation through a thin cover of usually permeable Quaternary sediments. Groundwaters flowing northwards form local, transitional and regional systems of circulation. About 70% of waters take part in local circulation systems, using about 30 to 60% of thickness of the intensively saturated zone whereas the remaining part supplies transitional and regional circulation systems.
Summary
The paper presents a hydrogeological model for the Lublin Cretaceous. The massif built of carbonate rocks displays dense and relatively regular network of fissures. The most important fissures, i.e. those bearing decisive influence on circulation and accumulation of waters, are supracapillary ones (over 0.25 mm in width), related to orthogonal joint system. In turn, intensity of flow appears controlled by fissures which accompany dislocation zones cutting the massif. The latter form concentrated flows as they drain water flowing in dispersed way in a network of minor fissures. The width and depth range of water-bearing fissures depends on lithological development and mechanic properties of rocks, especially their strength to compression and susceptibility to swelling. The above mentioned features of the massif are responsible for vertical and lateral zonation in its hydrogeological properties.
Despite of the above mentioned zonal differentiation of properties, Upper Cretaceous rocks form a single aquifer with hydraulic connections. Waters present in this aquifer are mainly related to direct percolation of precipitation water or percolation through a thin cover of usually permeable Quaternary sediments. Groundwaters flowing northwards form local, transitional and regional systems of circulation. About 70% of waters take part in local circulation systems, using about 30 to 60% of thickness of the intensively saturated zone whereas the remaining part supplies transitional and regional circulation systems.