ORIGIN AND AGE OF SALINE WATERS IN BUSKO SPA (SOUTHERN POLAND) DETERMINED BY ISOTOPE, NOBLE-GAS AND HYDROCHEMICAL METHODS - EVIDENCE OF INTERGLACIAL AND PRE-QUATERNARY WARM CLIMATE RECHARGES

In the Busko and Solec Spas, saline sulphide and sulphate waters are e xploited at different depths. The shallow water system in Busko is rel ated to an interglacial or interstadial period shown by the lack of tr itium and C-14 and its delta(18)O and delta D values equal to that of modern water. The noble gas temperatures (NGT) are somewhat lower than the present air temperatures, but the He-4 and Ar-40 ages of about 90 -480 ka confirm a Pleistocene recharge. The delta(18)O and delta D val ues of the deep system are much heavier than those of local modern wat ers, which may mean the recharge of a warm pre-quaternary climate. The He-4, Ar-40 and Ne-21 contents and the NGT values confirm the deep sy stem to be recharged at the pre-Quaternary stages of the present hydro logic cycle, i.e. after the sea transgression in the Badenian. High SO 42- contents indicate that the Cl- and SO42- in both systems originate d from simultaneous leaching of NaCl and gypsum. Other components can be explained by cation exchange between water and Badenian clay minera ls in marls (e.g. Ca2+ for Mg2+ and Na+ for K+) and by the decay of ma rine organic matter supplying Br-, I- and B. (C) 1997 Elsevier Science Ltd.