Stratigraphy and deformation history of the Jurassic coal bearing series in the Eastern Mecsek (Hungary)

• Published in: International journal of coal geology Vol. 102; pp. 35 - 51
• Main Authors: Püspöki, Zoltán, Forgács, Zoltán, Kovács, Zsolt, Kovács, Endre, Soós-Kablár, Jolán, Jäger, László, Pusztafalvi, János, Kovács, Zoltán, Demeter, Gábor, McIntosh, Richard William, Buday, Tamás, Kozák, Miklós, Verbőci, József
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 30.11.2012; Elsevier
• Subjects: Coal; Earth sciences; Earth, ocean, space; Exact sciences and technology; Hungary; Mecsek; Sedimentary rocks; Seismic interpretation; Sequence stratigraphy; Stratigraphy; Thrust wedge; Hungary; Central Europe; Europe; Seismic interpretation; Sequence stratigraphy; Thrust wedge; Hungary; Mecsek; Coal; Mesozoic; thickness; coal seams; well logs; coal exploration; seismic profiles; drill cores; underground mining; anticlines; brittle deformation; carbonaceous rocks; models; cost; deep drilling; sedimentary rocks; Jurassic; seismic methods; sequence stratigraphy; interpretation; gasification; coal; thrust; Phanerozoic
• ISSN: 0166-5162; 1872-7840
• DOI: 10.1016/j.coal.2012.07.009

Based on integrated interpretation of well-log and core data of 60 fully cored deep drillings and 2D seismic profiles, sequence stratigraphic and structural development models have been elaborated for the “Máza-South–Váralja-South” coal exploration site and for the Northern Imbricates, Eastern Mecsek, SW Hungary. Twenty four mostly coal capped parasequences and 4 sequences have been identified in the deltaic series of the coal bearing formation. Coal seams of high sulfur content are related to early transgressive systems tracts, while those with low sulfur content and great thickness are associated to late transgressive systems tracts. The sequences were traced on seismic profiles and mapped by subsurface methods. The structural reconstruction indicates that an open, almost symmetric, southward plunging anticline was formed in the Máza-South–Váralja-South area striking practically north–south. This anticline has a gradual transition westward, into another open, almost symmetric, westward plunging anticline. Related to the Cretaceous–Paleogene brittle deformation a set of thrusts with northern vergence were formed as the result of an in sequence thrust wedge development causing shortening of 13%. The Northern Imbricates has been re-interpreted as the result of the Neogene activity of this thrust wedge development; its Miocene development represents an in sequence thrust and a series of out of sequence backthrusts causing shortening of 22.5%. This multi-phase compressive deformation history caused the significant (34%) increase of the coal resources in the study area. However, it also resulted in strong structural fragmentation and multiple coal seams in the coal bearing formation increasing the costs of underground mining and the risks of underground coal gasification. ► We analyzed the area of one billion tonne hard coal in the Mecsek (Hungary). ► The formation is a Jurassic siliciclastic succession with brittle deformation. ► The method was an integrated analysis of downhole and seismic data. ► Coal capped parasequences of early and late transgressions were identified. ► Thrust wedge development with shortening of 35.5% has been reconstructed.