Wkład profesora Henryka Jurkiewicza w poznanie budowy geologicznej regionu świętokrzyskiego i Ponidzia

Henryk Jurkiewicz graduated in geology from the Jagiellonian University in Cracow and began his professional career in the Petroleum Exploration Company in Cracow, later continued in Krosno and Jasło. He worked in the Carpathians and the Carpathian Foredeep, contributing to the discovery of numerous oil and gas fields (Fig. 1). Intensive exploration in eastern Małopolska allowed the deep-seated geology of the Carpathian Foredeep to be recognized within a few years, encouraging further drilling in the region of the Holy Cross Mountains and the Nida River. This matter was taken up by the Kielce Branch of the Geological Institute, where H. Jurkiewicz (Fig. 2)started working in 1961. In the first stage, he designed three drillings (one in the Holy Cross Mountains and two on its western margin). In the second stage, there were already 12 drillings within the central and northern parts of the Miechów Synclinorium (Nida River region), and the third stage involved six drillings in the far western and northern margin of the Holy Cross Mountains (Fig. 3). The drilling results ruled out the potential for hydrocarbon occurrence within the Holy Cross Mountains due to the lack of regional sealing of Paleozoic sediments. A different situation exists in the Miechów Synclinorium, where Paleozoic sediments are covered by Permian, Triassic, Jurassic and Cretaceous formations. However, drilling results showed that their lithological composition and thickness vary significantly depending on the region and the activity of palaeotectonic structures, with particular emphasis on the Włoszczowa Swell (Fig. 4, Fig. 5). Deep subsurface reconnaissance in the Miechów Synclinorium, combined with results from the third stage of drilling, also provided the opportunity for correlation and comparisons, especially of Devonian formations, which developed in shallower basins (Kielce Zone) and deeper depositional environments (Łysogóry Zone to the north, and the Miechów Zone to the south) (Fig. 6). Petrographic data from drillings also allowed determining the geotectonic position of the Holy Cross Mountains and Nida River region, as well as neighbouring areas, classifying this region as a province with Cadomian basement consolidation (Fig. 7). The geological and structural development in the described area was conditioned by numerous episodes of tectonic movements from the Paleozoic to the Neogene. The most significant ones occurred at the end of the Variscan and Alpine epochs, all under epicratonic platform conditions. The spatial and temporal diversity resulting from various geological processes is well represented by the sub-Permian map for Jurkiewicz’s drilling projects conducted between 1963 and 1977.