Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics
In this study, siliceous nodules from the world-famous Myrtos beach, as well as from Avithos beach, in the western flanks of Kefalonia Island in Greece are examined by means of petrographical, mineralogical, geochemical and micropaleontological methods. The objectives of this study are to characteri...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/1/101 |
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| author | Paraskevi Lampropoulou Vayia Xanthopoulou Małgorzata Wojtaszek-Kalaitzidi Petros Petrounias Elena Zoumpouli George Iliopoulos Stavros Kalaitzidis |
| author_facet | Paraskevi Lampropoulou Vayia Xanthopoulou Małgorzata Wojtaszek-Kalaitzidi Petros Petrounias Elena Zoumpouli George Iliopoulos Stavros Kalaitzidis |
| author_sort | Paraskevi Lampropoulou |
| collection | DOAJ |
| description | In this study, siliceous nodules from the world-famous Myrtos beach, as well as from Avithos beach, in the western flanks of Kefalonia Island in Greece are examined by means of petrographical, mineralogical, geochemical and micropaleontological methods. The objectives of this study are to characterize the textural and compositional features of the nodules, with the aim to provide an initial interpretation of their origin and their diagenetic evolution. The studied siliceous nodules are hosted within Lower Cretaceous thin-bedded limestones at Myrtos and Upper Eocene limestones at Avithos. Nodules from both areas display a characteristic concentric texture at a macroscopic and microscopic scale. They both have a dense fine-grained siliceous sedimentary fabric, composed mainly of microcrystalline or cryptocrystalline quartz and moganite with common residual calcite in the case of Avithos. These results, and in particular the shape of the nodules, along the textural and compositional characteristics, indicate different conditions of formation in the two localities, both during the early epigenetic stages, as well as later during the diagenetic processes. Myrtos nodules originated from Si-precursors deposited in a pelagic environment, going through intense Si-replacement. Avithos nodules were deposited in a more proximal environment, being influenced by a less intense silicification. Nevertheless, the higher degree of recrystallization of Avithos samples indicates a syn- or post-diagenetic tectonic activity that resulted in the circulation of geothermal fluids. The conclusions drawn from this work demonstrate the usefulness of thorough studies of siliceous nodules in order to get a more comprehensive understanding of the initial depositional conditions, as well as diagenetic pathways and processes. |
| first_indexed | 2024-03-10T00:52:04Z |
| format | Article |
| id | doaj.art-a22d4a5f49314d468e4d398f3aa05adb |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T00:52:04Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-a22d4a5f49314d468e4d398f3aa05adb2023-11-23T14:50:17ZengMDPI AGMinerals2075-163X2022-01-0112110110.3390/min12010101Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic CharacteristicsParaskevi Lampropoulou0Vayia Xanthopoulou1Małgorzata Wojtaszek-Kalaitzidi2Petros Petrounias3Elena Zoumpouli4George Iliopoulos5Stavros Kalaitzidis6Department of Geology, University of Patras, 26504 Patras, GreeceDepartment of Geology, University of Patras, 26504 Patras, GreeceInstitute for Chemical Processing of Coal, 41803 Zabrze, PolandDepartment of Geology, University of Patras, 26504 Patras, GreeceDepartment of Geology, University of Patras, 26504 Patras, GreeceDepartment of Geology, University of Patras, 26504 Patras, GreeceDepartment of Geology, University of Patras, 26504 Patras, GreeceIn this study, siliceous nodules from the world-famous Myrtos beach, as well as from Avithos beach, in the western flanks of Kefalonia Island in Greece are examined by means of petrographical, mineralogical, geochemical and micropaleontological methods. The objectives of this study are to characterize the textural and compositional features of the nodules, with the aim to provide an initial interpretation of their origin and their diagenetic evolution. The studied siliceous nodules are hosted within Lower Cretaceous thin-bedded limestones at Myrtos and Upper Eocene limestones at Avithos. Nodules from both areas display a characteristic concentric texture at a macroscopic and microscopic scale. They both have a dense fine-grained siliceous sedimentary fabric, composed mainly of microcrystalline or cryptocrystalline quartz and moganite with common residual calcite in the case of Avithos. These results, and in particular the shape of the nodules, along the textural and compositional characteristics, indicate different conditions of formation in the two localities, both during the early epigenetic stages, as well as later during the diagenetic processes. Myrtos nodules originated from Si-precursors deposited in a pelagic environment, going through intense Si-replacement. Avithos nodules were deposited in a more proximal environment, being influenced by a less intense silicification. Nevertheless, the higher degree of recrystallization of Avithos samples indicates a syn- or post-diagenetic tectonic activity that resulted in the circulation of geothermal fluids. The conclusions drawn from this work demonstrate the usefulness of thorough studies of siliceous nodules in order to get a more comprehensive understanding of the initial depositional conditions, as well as diagenetic pathways and processes.https://www.mdpi.com/2075-163X/12/1/101chertsflint-like rocksKefalonia islandmoganitesiliceous nodules |
| spellingShingle | Paraskevi Lampropoulou Vayia Xanthopoulou Małgorzata Wojtaszek-Kalaitzidi Petros Petrounias Elena Zoumpouli George Iliopoulos Stavros Kalaitzidis Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics Minerals cherts flint-like rocks Kefalonia island moganite siliceous nodules |
| title | Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics |
| title_full | Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics |
| title_fullStr | Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics |
| title_full_unstemmed | Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics |
| title_short | Characterization of Siliceous Nodules in Western Kefalonia Ιsland Greece: An Initial Approach to Their Formation and Diagenetic Characteristics |
| title_sort | characterization of siliceous nodules in western kefalonia ιsland greece an initial approach to their formation and diagenetic characteristics |
| topic | cherts flint-like rocks Kefalonia island moganite siliceous nodules |
| url | https://www.mdpi.com/2075-163X/12/1/101 |
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