Analiza pola geotermicznego Polski na tle Europy ze szczególnym uwzględnieniem zagadnień tektonofizycznych i hydrogeotermalnych
Abstract
AN ANALYSIS OF GEOTHERMAL FIELD OF POLAND ON THE BACKGROUND OF EUROPE, WITH A SPECIAL ATTENTION PAID TO TECTONOPHYSICAL AND HYDROTERMAL PROBLEMS
Summary
A map of heat flow in Poland and surrounding areas and maps of geothermal gradient and geoisoterms from 1 km and 2 km depths are given. The image of distribution of heat flow in Poland was included to the geothermal map of Europe (31). The problem of interpretation of distribution of geothermal field of Poland versus that of Europe was analysed taking into account the problems of tectonophysics and the knowledge of hydrogeothermal potential. The analysis of several facts concerning the heat field, seismoIogical structure of Earth crust and upper mantle as well as the history of tectonic development of Poland and Europe has shown that differences in values of heat flow for geotectonic areas of different age are presumably related to differences in values of subcrustal Earth heat flow which is generally higher in tectonically younger areas. This is also connected with the depth of occurrence of zone of partial melting of the upper mantle. The temperature prevailing in the crust/upper mantle transitional zone equals about 750°C and 550°C in the areas of the Fore-Sudetic Monocline with Variscan basement (Q = 1.6 • 10-6 cal/cm2s) and the Precambrian Platform (Q = 1 • 10-6 cal/cm2s), respectively. It is also shown that the interdependance between heat flow and surficial heat production is of universal nature for pre-Variscan, tectonically stable regions as well as younger, Meso-Cenozoic orogens. The value of heat flow in western and north-western Poland, northern GDR, GFR and North Sea is equally high as the values Q for the western Europe, which are in contrast with low values of heat flow for the East European Precambrian Platform. This speaks against the hypothesis of extension of the Precambrian Platform westwards as far as southern England. It is shown that the areas of south-western and central Poland are favourable for obtaining high-thermal waters with temperatuaes exceeding 50°C at depths from 1.2 to 1.5 km.
Summary
A map of heat flow in Poland and surrounding areas and maps of geothermal gradient and geoisoterms from 1 km and 2 km depths are given. The image of distribution of heat flow in Poland was included to the geothermal map of Europe (31). The problem of interpretation of distribution of geothermal field of Poland versus that of Europe was analysed taking into account the problems of tectonophysics and the knowledge of hydrogeothermal potential. The analysis of several facts concerning the heat field, seismoIogical structure of Earth crust and upper mantle as well as the history of tectonic development of Poland and Europe has shown that differences in values of heat flow for geotectonic areas of different age are presumably related to differences in values of subcrustal Earth heat flow which is generally higher in tectonically younger areas. This is also connected with the depth of occurrence of zone of partial melting of the upper mantle. The temperature prevailing in the crust/upper mantle transitional zone equals about 750°C and 550°C in the areas of the Fore-Sudetic Monocline with Variscan basement (Q = 1.6 • 10-6 cal/cm2s) and the Precambrian Platform (Q = 1 • 10-6 cal/cm2s), respectively. It is also shown that the interdependance between heat flow and surficial heat production is of universal nature for pre-Variscan, tectonically stable regions as well as younger, Meso-Cenozoic orogens. The value of heat flow in western and north-western Poland, northern GDR, GFR and North Sea is equally high as the values Q for the western Europe, which are in contrast with low values of heat flow for the East European Precambrian Platform. This speaks against the hypothesis of extension of the Precambrian Platform westwards as far as southern England. It is shown that the areas of south-western and central Poland are favourable for obtaining high-thermal waters with temperatuaes exceeding 50°C at depths from 1.2 to 1.5 km.