Meeting of Young Geoscientists Characterization of phyllosilicates from overpressured zones of Endrőd Formation (Makó Trough, Pannonian Basin, Hungary) Tóth Ferenc Ph.D. student University of Szeged Department of Mineralogy, Geochemistry and Petrology Meeting of Young Geoscientists Békéscsaba, 2013

Reveal of disputed processes and open questions The aim of the study Diagenetic processes of the Makó Trough Published/unpublished reports National/international literatures Why the clay mineral alteration? Great influence on diagenesis and HC Available international references Studies from Pannonian Basin Contradictory results from Makó Trough Did the overpressure influence the clay mineral alteration? Reveal of disputed processes and open questions

Geological overview of Makó Trough

Lithological cross section of Makó Trough Executive summary on core analysis data and procedures on the wells drilled in the Makó trough. Final report; EDITED BY Zoltán Unger (2008), Geological Institute of Hungary (MÁFI), Budapest, Hungary, 64 p (unpublished).

Illite/smectite alteration

Macroscopic petrography Hód-I well 4538-4546 m Unlayered, fine- grained, micaceous sandstone Endrőd Formation – Vásárhely Member 5167-5183 m Classic marl, claymarl Endrőd Formation – Tótkomlós Member ~ 5400 m Fine-grained conglomerate Endrőd Formation – Dorozsma Member

Identification of clay minerals X-ray diffractometry (XRD) on Hód-I samples Other researches (Bérczi & Viczián, 1972; Grasselly, 1973; Lovas, 2004)

Origin of the ˮsmectite anomalyˮ

Results of clay mineralogy Very likely that the ˮsmecite anomalyˮ in the overpressured zones does not exist (Lovas, 2004)! VERMICULITE has been identified as smectite (formed via chemical weathering of biotite) Circumstances of vermiculite formation (Fe2+--> Fe3+) Meteoric water Diagenetical fluids Early diagenesis Burial diagenesis Petrography

Microscopic petrography Hód-I well

Summary X-ray diffraction Petrography Overpressure could not Changing in sedimentation Identification of vermiculite Petrography Early calcite cement Low level of mechanical compaction Undeformed bioclasts Dolomitization Burial diagenesis Absence of SO42- Alteration of biotite Reductive environment Framboidal pyrite BSR (mostly 0.01-150 m, max 60°C) Oxidative environment Vermiculite in secondary pores Overpressure could not have influenced the clay mineral alterations Vermiculite could be formed by burial diagenesis

Summary X-ray diffraction Petrography Overpressure could not Changing in sedimentation Identification of vermiculite Petrography Early calcite cement Low level of mechanical compaction Undeformed bioclasts Dolomitization Burial diagenesis Absence of SO42- Alteration of biotite Reductive environment Framboidal pyrite BSR (mostly 0.01-150 m, max 60°C) Oxidative environment Vermiculite in secondary pores Overpressure could not have influenced the clay mineral alterations Vermiculite could be formed by burial diagenesis Main questions What kind of changing in sedimentation? When and how does oxidative environment exist? Was it a local or regional process? Petrography (provenance) Scanning Electron Microscopy (SEM) X-ray Fluorescence (XRF) Analysis X-ray Diffractometry (XRD)

Thank you for your kind attention! I would like to express my great thank for helping in this study to Andrea Varga and Béla Raucsik. Thank you for your kind attention! Bérczi, I. & Viczián, I. (1973): Üledékes kőzettani vizsgálatok a dél-alföldi neogénben. Földtani Közlöny 103, 3-4, 319-339 (in Hungarian). Executive summary on core analysis data and procedures on the wells drilled in the Makó trough. Final report; EDITED BY Zoltán Unger (2008), Geological Institute of Hungary (MÁFI), Budapest, Hungary, 64 p (unpublished). Hámor-Vidó, M. & Viczián, I. (1993): Vitrinite reflectance and smectite content of mixed-layer illite/semctites in Neogene sequences of the Pannonian Base, Hungary. Acta Geologica Hungarica 36, 1, 197-209. Judik, K. (2001): Agyagásvány átalakulások a Hódmezővásárhely-1 fúrás rétegsorában. MSc. thesis, Eötvös Lóránd Tudományegyetem Természettudományi Kar, Ásványtani Tanszék (in Hungarian). Lovas, A. (2004): Az agyagásványok individualizmusa, a diagenezis során kialakuló szerkezeti állapotok és átmenetek regionális vizsgálata. T 32450 sz. OTKA final report (in Hungarian).