Thermal properties of the crust and the lithosphere–asthenosphere boundary in the area of Poland from the heat flow variability and seismic data

Abstract

High-resolution 3D seismic P-wave velocity model of Poland (Grad et al., Tectonophysics 666:188-210, 2016) and corrected for paleoclimate heat flow map (Majorowicz and Wybraniec, Int J Earth Sci 100(4):881-887, 2011) gridded to a common mesh are used together with four independent thermal models of the crust and upper mantle to calculate heat flow variation with depth and geotherms. Heat flow at Moho depth are calculated and mapped and both confirm large variability with an elevated mantle heat flow (circa 30-40 mW/m 2) in the Paleozoic Platform which is some 10-20 mW/m 2 higher than Moho heat flow in the northeastern and southeastern Poland which belong to a variety of tectonic terranes (the oldest Precambrian Craton, younger Cadomian, Trans-European Suture Zone, Carpathians). Temperatures calculated for the crust show consistent pattern: higher temperatures beneath the Paleozoic Platform and lower temperatures beneath the Precambrian and Cadomian units. At 10 km depth this difference is about 150 °C, about 300 °C at 20 km depth, and about 400 °C at 50-60 km. Assuming the calculated isotherm 580 °C as Curie temperature the magnetic crust thickness was determined as 5-10 km only beneath the Polish Basin, circa 20 km in Carpathians, circa 30 km in Sudetes, and 35-40 km beneath the Precambrian and Cadomian units. Such a thick magnetic crust results from a great depth of Curie temperature, thick crystalline crust, and thin sediments. Mantle heat flow variability is mainly correlating with measured surface heat flow and influences geotherms. Calculated thermal LAB depth follows patterns of heat flow and Moho heat flow variability through Poland with thinnest lithosphere in the high surface heat flow and high mantle heat flow areas. Comparison of this thermal LAB depth estimates with seismic data based LAB depth shows general coincidences when Precambrian Craton vs Paleozoic Platform are considered along the P4 seismic experiment data model (circa 190 km depth vs some 90 km depth, respectively). However, significant differences exist in many areas and especially for the SE Poland when compared with map for the whole of Poland compiled from other seismic reported data.

Terrestrial heat flow versus crustal thickness and topography – European continental study

“…However, it may be biased by differences in radiogenic crustal heat production in both areas of different geological history. It seems that thicker crust of the cratons is characterized by low upper crustal heat production than the younger and thinner crust of the Paleozoic platform (Majorowicz et al 2019). Therefore, thinner crust -higher heat flow, thicker crust lower heat flow leads to negative HF vs Moho depth correlation seen in Figure 1.…”

Burial and Thermal History Modeling of the Paleozoic–Mesozoic Basement in the Northern Margin of the Western Outer Carpathians (Case Study from Pilzno-40 Well, Southern Poland)

“…10 Ma [34], which allows maximum burial age in the study area to be established. Apatite fission track analyses and helium dating indicate that the foredeep Miocene succession in the Pilzno-40 area has not been buried deeper than 1.5 to 2 km [34], assuming a paleogeothermal gradient of the order of 25 to 29 • C/km [35,36]. This interpretation is consistent with reconstruction based on the seismic data [34], and the low thermal maturity of organic matter in the Miocene strata of the Carpathian Foredeep, which is in the range of 0.3 to 0.6%VR [37,38].…”

Retrofit Decarbonization of Coal Power Plants—A Case Study for Poland

“…Research conducted by Majorowicz et al [77] has recently produced ground temperature maps for Poland depths up to 60 km, allowing for the exploration of deeper-drill EGS system potential across Poland. Majorowicz et al also defined Curie temperature depth, defined as temperature at which rocks and minerals lose their permanent magnetic properties (which occurs at a temperature close to 580 • C) [78].…”

“…If the technology for drilling and extracting geothermal heat out of very deep, very high temperature rock were to be developed, the ability to re-use a coal power plant or unit site and equipment requires that the geothermal wells are drilled at, or adjacent to, the existing coal power plant sites. The prospect for this can be explored by overlaying major coal power units with the heat temperature maps produced by Majorowicz et al [77]. At 10 km depth, as seen on the left side in Figure 9 (red dots mark major coal units), the Poznań-Karolin and Pątnów plants are within areas expected to have ground temperatures in excess of 300 • C. While no coal plant steam cycle equipment could effectively be re-used at such low temperature without modifications, the theoretical potential for re-use of site and some of the site equipment (make-up water supply, district heating connections, switchyard) cannot be excluded.…”