Seismic and Field Traces of the Holešov and Kroměříž faults

KOLAČNÝ, Radek; David KOLAČNÝ; Rostislav MELICHAR a Martin ŠUŤJAK. Seismic and Field Traces of the Holešov and Kroměříž faults. In 21st Meeting of the Central European Tecotnic Studies Group. 2025.

Základní údaje

Originální název

Seismic and Field Traces of the Holešov and Kroměříž faults

Název česky

Seismické a Terénní Indikace Holešovského a Kroměřížského zlomu

Autoři

KOLAČNÝ, Radek; David KOLAČNÝ; Rostislav MELICHAR ORCID a Martin ŠUŤJAK

Vydání

21st Meeting of the Central European Tecotnic Studies Group, 2025

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Další údaje

Jazyk

angličtina

Typ výsledku

Konferenční abstrakt

Obor

10505 Geology

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Označené pro přenos do RIV

Ne

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova česky

Vnější Západní Karpaty, Příkrovy, Hornomoravský úval, Tektonika, Seismické Interpretace, Holešovský zlom, Kroměřížský zlom

Klíčová slova anglicky

Outer Western Carpathians, Nappes, Upper Morava Basin, Tectonics, Seismic Interpretations, Holešov fault, Kroměříž fault

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Anotace

V originále

The Holešov and Kroměříž faults are located at the boundary between the Outer Western Carpathians and the Bohemian Massif. The depression delineated by these two faults is known as the Upper Moravian Basin. The Holešov Fault is situated at the northeastern boundary of this structure, whereas the Kroměříž Fault is positioned at the southwestern boundary. To characterize these faults, a combination of dozens of two-dimensional seismic profiles and multiple borehole datasets was used. Data were imported and processed using Petrel software, allowing analysis of stratigraphic horizons and dislocations that intersect them. Three geological units were interpreted in this area: the Variscan basement of the Bohemian Massif, the autochthonous Neogene sedimentary cover, and the flysch nappes of the Outer Western Carpathians. These units are separated by two prominent stratigraphic surfaces: the nonconformity between the Neogene sedimentary rocks and the basement and the thrust surface of the nappes. Variations in the thickness of the Neogene deposits allowed us to distinguish between synsedimentary and post-sedimentary fault activity. Two sets of local faults were identified, mainly differing in their geological age of activity. 1. First-stage faults – These faults were active during the deposition of Neogene sediments, influencing the sedimentary processes. Their activity is reflected in the thickness variations of the sedimentary layers on either side of the faults, indicating differential subsidence and changes in the localized accommodation space. Such variations suggest that the movement along the faults occurred contemporaneously with sedimentation, leading to an uneven distribution of the deposits. These faults affect both the Variscan basement and the bedding of the autochthonous Neogene but do not disrupt the upper lying flysch nappes. Their formation preceded the thrusting of the Carpathian flysch rocks. 2. Second-stage faults – These faults affect all units considered, including the flysch nappes. Therefore, it indicates that they are younger in age. They became active only after the completion of the Neogene sedimentation. Since the faults occurred after deposition, the sedimentary layers on both sides of the fault exhibit a uniform thickness, indicating that the displacement was purely structural and did not influence the original depositional processes. These faults should be associated with later tectonic events. The seismic profiles indicate that both major faults were active during both the first and second stages of deformation. Both faults exhibit a normal-fault character, with the Holešov Fault dipping to the southwest and showing a maximum offset of 735 m in the Variscan basement. On the Kroměříž Fault dips to the northeast, with an offset of 990 m.