Upper Jurassic carbonate buildups in the Miechów Trough, southern Poland – insights from seismic data interpretations

Abstract

The geometry and internal architecture of the Upper Jurassic carbonate depositional system in the epicontinental basin of central and western Europe and within the northern margin of the Tethyan shelf are hitherto only partly recognized, especially in areas with thick Cretaceous and younger cover such as the Miechów Trough. In such areas, seismic data are indispensable for the analysis of a carbonate depositional system, in particular for the identification of the carbonate buildups and the enveloping strata. The study area is located in the central part of the Miechów Trough that in the Late Jurassic was situated within the transition zone between the Polish part of the central and western European epicontinental basin and the Tethys Ocean. This paper presents the results of the interpretation of 2D seismic data calibrated by deep wells that document the presence of large Upper Jurassic carbonate buildups. The lateral extent of particular structures is in the range of 400–1000 m, and their heights are in the range of 150–250 m. The interpretation of seismic data revealed that the depositional architecture of the subsurface Upper Jurassic succession in the Miechów Trough is characterized by the presence of large carbonate buildups surrounded by basinal (bedded) limestone and marly-limestone deposits. These observations are compatible with depositional characteristics of well-recognized Upper Jurassic carbonate sediments that crop out in the adjacent Kraków–Częstochowa Upland. The presented study provides new information about carbonate open-shelf sedimentation within the transition zone in the Late Jurassic, which proves the existence of a much more extensive system of organic buildups which flourished in this part of the basin. The results obtained, due to the high quality of available seismic data, also provide an excellent generic reference point for seismic studies of carbonate buildups in other basins and of different ages.