Geochronology of Late Cenozoic volcanism in the area of Van Lake,Turkey: An example of development dynamics for magmatic processes |
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Authors: | V A Lebedev E V Sharkov M Keskin V Oyan |
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Institution: | (1) Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun, Turkey;(2) Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Yuzuncu Yil University, Van, Turkey |
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Abstract: | An isotope-geochronological study has been performed to examine the products of Late Cenozoic collision volcanism on the northern
coast of Van Lake, Turkey. We obtained 45 new K-Ar dates, based on which the principal time characteristics of volcanic activity
in the region have been determined. The total duration of magmatic activity in the area of the northern coast of Van Lake
has lasted ∼15 myr; it has had an expressed discrete nature, when periods of intense volcanic activity alternated with lasting
breaks in eruptions. Four stages of Neogene-Quaternary volcanism have been identified: Middle Miocene (15.0–13.5 myr), Late
Miocene (10–9 myr), Pliocene (5.8–3.7 myr), and Quaternary (1.0–0.4 Ma). The average duration of the stages has been 1–2 myr;
the stages were separated from each other with periods of inactivity of approximately equal lengths (∼3 myr). For each of
the Pliocene and Quaternary stages, three additional phases of volcanism have been identified, which were separated from each
other with short time intervals (a few hundred thousand years). The last burst of volcanic activity in the area in question
took place ∼400 ka; similar to Quaternary volcanism in general, it was not characterized by a high intensity. An important
result of the studies performed was to confirm the existence of a separate Middle Miocene stage of collision volcanism for
the Caucasian-Anatolian Segment of the Alpine Fold Belt. The data generated allow concluding that Neogene-Quaternary volcanism
in this portion of the belt started much earlier (∼15 Ma) than assumed by the majority of the previous researchers. |
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