The dating of young volcanic eruptions is often difficult with respect to the time range between the sensitivities of radiocarbon and the routine K-Ar methods (ca. 50 ka and 1 Ma, respectively); problems can also arise due to the absence of suitable K-bearing minerals (e.g. leucite, sanidine) or charcoal fragments. However, by combining zircon U-Th and (U-Th)/He dating this critical time-window can be covered. Because of the low closure temperature of the zircon (U-Th)/He system (~150–180 °C), and the fact that zircon is a widespread accessory mineral in most of the volcanic eruption products, this method is suitable for dating the age of eruptions directly. Furthermore, over the last decade,the advantages of the method have been supported by its expansion and application by international researchers when dating young (< 1 Ma) eruption events. In this Hungarian review paper a summary is presented of the theoretical principles, basic methodology and past developments of the (U-Th)/He geochronology; it also shows the applicability of the method for dating young (< 1 Ma) volcanic eruptions. For the purpose of this study eruption products were selected from the Carpathian–Pannonian Region and they are related to the youngest volcanic activity (Ciomadul, South Harghita) known in the area. These are the andesitic dome of Dealul Mare and the pyroclastic deposit close to the village of Bixad; these features have eruption ages of 843 ± 27 kyrs and 32.6 ± 1.0 kyrs, respectively. The selected samples are good for demonstrating each step of the method from the measured raw data to the corrected age, and also for illustrating its adequacy for deriving reliable eruption ages for young volcanic products.
|Translated title of the contribution||Methodology and application of zircon (U-Th)/He geochronology in the dating of young (<1 Ma) eruptions|
|Number of pages||20|
|Publication status||Published - Jan 1 2017|
ASJC Scopus subject areas
- Geochemistry and Petrology