Formal definition and description of lithostratigraphic units related to the Miocene silicic pyroclastic rocks outcropping in Northern Hungary: A revision
Formal definition and description of lithostratigraphic units related to the Miocene silicic pyroclastic rocks outcropping in Northern Hungary: A revision
复制标题
与匈牙利北部中新世硅质火山碎屑岩相关的岩石地层单元的正式定义和描述：修订
DOI：
10.31577/geolcarp.73.2.3
复制
发表时间：
2022
影响因子：
1.3
通讯作者：
L. Fodor
中科院分区：
文献类型：
--
作者：
R. Lukács;S. Harangi;P. Gál;J. Szepesi;A. Di Capua;G. Norini;R. Sulpizio;G. Groppelli;L. Fodor
早中新世至中中新世期间，大量火山岩浆的反复爆发导致潘诺尼亚盆地火山碎屑沉积物覆盖至少50，000平方公里。它们形成延伸的标志层，因此这些火山碎屑岩建造具有重要的地层学意义。这些岩石的岩石地层特征和分类可以追溯到一个多世纪，并已广泛用于地质填图等。在本文中，我们概述了以前的地层方案开发的火山碎屑产物在北方匈牙利，然而，使用新的地质年代学，火山，岩石学和地球化学的结果，我们提出了一个修订的岩石地层单位，包括单位名称。四个主要单位被区分，命名，并按照国际地层指南描述。根据可达性和代表性，重新定义了修订后的单元的层型。新划分的4个岩石地层单位是：（1）Tihamér流纹岩火山碎屑凝灰岩组（原Gyulakeszi组），18.2-17.1 Ma（Bogács期-Karpatian期）;（2）Bogács英安岩火山砾凝灰岩组（以前归入Tar组），16.8-16.2 Ma（Karpatian）;（3）焦油英安岩火山碎屑凝灰岩组，15.1-14.8 Ma（Badenian）;（4）Harsány流纹岩火山碎屑凝灰岩组，14.7-14.4 Ma（Badenian）--四个先前存在的地层合并在后者中。其中三个单元在匈牙利周围和潘诺尼亚盆地之外也有相应的远源火山产物。根据岩石学特征以及玻璃碎片、幼年碎屑和锆石的化学成分，可以对分散的火山产物进行对比。
Repeated explosive eruptions of large volume silicic magmas during the earlyto mid-Miocene resulted in pyroclastic deposits covering at least 50,000 km2 in the Pannonian Basin. They form extended marker horizons and therefore these pyroclastic formations have a great stratigraphic importance. Lithostratigraphic characterization and classification of these rocks go back for more than a century and have been used widely in geological mapping among other things. In this paper, we outline the former stratigraphical schemes developed for silicic pyroclastic products in Northern Hungary; however, using the new geochronological, volcanological, petrological, and geochemical results, we propose a revision of the lithostratigraphic units, including the unit names as well. Four main units are distinguished, named, and described following the International Stratigraphic Guide. Stratotypes of the revised units were also redefined based on accessibility and representativeness. The four newly-defined lithostratigraphic units are the following: (1) The Tihamér Rhyolite Lapilli Tuff Formation (formerly Gyulakeszi Fm.), 18.2–17.1 Ma (Ottnangian–Karpatian); (2) The Bogács Dacite Lapilli Tuff Formation (formerly classified into the Tar Fm.), 16.8–16.2 Ma (Karpatian); (3) The Tar Dacite Lapilli Tuff Formation, 15.1–14.8 Ma (Badenian) and (4) The Harsány Rhyolite Lapilli Tuff Formation, 14.7–14.4 Ma (Badenian) – four formerly existing formations merged in the latter. Three of these units have corresponding distal volcanic products recognized around Hungary and beyond the Pannonian Basin as well. A correlation of the scattered volcanic products can be made based on lithological characteristics, as well as the chemical composition of glass shards, juvenile clasts, and zircon.