Crustal structure at the Trans-European Suture Zone in northwest Poland based on gravity data

Abstract

A new gravity model of the crustal structure of the Trans-European Suture Zone in the northwestern Poland has been constructed. The Bouguer anomaly map, obtained after stripping off the three-dimensional gravity effect of the sedimentary cover down to the Zechstein formations, is characterized by a 50 mGal gravity anomaly. We have assumed that the short-wavelength components derive from upper crustal intrusions and the long-wavelength components reflect crustal thickness and lateral heterogeneity which are strongly supported by the new seismic data along the LT-7 geotraverse. Quantitative modelling of gravity data along three profiles crossing the area indicate the presence of anomalous masses within the Lower Palaeozoic sequence, mainly along the Teisseyre-Tornquist Zone. Two of the profiles crossing the long-wavelength 'stripped' gravity high suggest the existence of a zone of 35 km crust above a dense upper mantle along the Teisseyre-Tornquist Zone. The extent of the zone can be determined based on the Bouguer anomalies interpretation.

The Trans-European Fault: a critical reassessment

“…While the changes across this area are not as marked as elsewhere along the profile, it is still of some significance. Gravity analysis confirms the presence of an anomaly in the same location, although it is less marked than other anomalies in the area (Krolikowski & Petecki, 1997). This anomaly could be due to the overlying sediments or possible deeper structures.…”

Crustal structure of the Trans‐European suture zone region along POLONAISE'97 seismic profile P4

“…The adjacent Paleozoic terranes to the southwest and the EEC to the northeast are characterized by near‐zero to positive gravity anomalies of up to +20 and +10 mGal, respectively. In spite of differences in the interpretation of crustal densities and structures reported by Grabowska and Raczyńska [1991] and Królikowski and Petecki [1997] for profiles across the TESZ, these workers agree on the existence of denser upper mantle beneath the TESZ (100–130 kg/m 3 ) than in neighboring regions.…”

Seismic basement in Poland

“…The EEC basement density of 2.71-2.75 g/cm 3 was modeled across the Skagerrak Graben (Lassen and Thybo 2012). In NW Poland, Królikowski and Petecki (2002) obtained a 2D density model along the LT-7 profile with basement values of 2.68 g/cm 3 for WEP and 2.82 g/cm 3 for EEP. Similar values were applied by Maystrenko and Scheck-Wenderoth (2013) in a 3D density model of the Central European Basin System and adjacent areas: 2.79-2.83 g/cm 3 for EEC basement, 2.67 g/cm 3 for Variscan granitoids, and 2.79 g/cm 3 for Variscan upper crust.…”