K-Ar geochronology of new volcanic centers eruptions in the Kazbek region of the Great Caucasus

Чернышев, И. В.; Arakelyants, M. M.; Lebedev, V. A.; Bubnov, S. N.; Gol’tsman, Yu. V.

doi:10.2205/1999es000024

Cited by 4 publications

(10 citation statements)

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“…Published results are summarized in recent publications [5][6][7][8], first age measurements have been done by Chemyshov et al [26]. The EPR dating technique also has been used for age determination but data given in ref.…”

Section: Discussionmentioning

confidence: 99%

“…The age of precaldera cycle obtained with the K-Ar method on rock samples (trachyandesite lava flow at the mouth of the Khudes river) is 800___ 150 ka [26]. The early stage of the caldera cycle is represented by the ignimbrites of the Bijtik-Tebe river valley and is characterized by the following ages: biotite, 740___60 ka; glass, 880_+70 ka; groundmass, 810___90 ka; plagioclase, 15700+_1000 ka; and pyroxene, 2700-+500 ka.…”

Section: Discussionmentioning

confidence: 99%

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EPR dating and evolution of the Elbrus volcano

et al. 2005

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Abstraer. This study is devoted to the reconstruction of the Elbrus volcano evolution by etectron paramagnetic resonance (EPR) dating. The following ages have been obtained for the Elbrus activity cycles: early caldera cycle was apparent between 340 and 250 ka ago and ci~anged into the denudation of volcano. Resumption of volcanic activity (late stage of caldera cycle) resulted in accumulation of thick volcanic rock mass (up to 2 km) took place about 170 ka ago. The end of this stage carne 70-60 ka ago soon after the intrusion of subvolcanic bodies 90-70 ka ago. After Late Pleistocene glaciation, volcanic activity resumed several times, however, we have dated with EPR only one eruption which occurred 6.7 ka ago. Comparison with the results of geomorpho[ogical, ~~C, KAr and U-Th sensitive high-resolution ion microprobe dating show that EPR dating of quartz from volcanic rocks may be used for the reconstruction of the Late Neo-Pleistocene and Holocene history of the Elbrus. For older rocks, EPR ages are younger than those obtained with conventional methods. The causes of this disagreement are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

EPR dating and evolution of the Elbrus volcano

et al. 2005

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“…Prod ucts of its activity are andesite-basalts of Surkh and Krandukh volcanoes (3.85-3.65 Ma [3]), acid and moderately acid (calc alkaline and K-Na subalka line) volcanic rocks of Verkhnechegemskaya caldera and Nizhnechegemskoe Highland (~2.8 Ma [12,13]), 1 Here and below in the text, the age of geological objects is shown as a date with an inaccuracy (for example 8 Here, acid, moderately acid tuffs or ignimbrites com pose a sequence up to 300 m thick. Many workers [13, etc.…”

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confidence: 99%

“…The rock composi tion varies from trachyandesite-basalts to dacites with domination of andesite volcanic rocks. The newest volcanism in this center evolved during the last 450 000-400 000 years [1]. At the end of the Early Neopleistocene in the place of the modern Kazbek Volcano there existed the predecessor volcano, lava flows of which moved largely to the south and north east along paleo valleys of the Mnaisidon and Devoraki rivers.…”

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Geochronological scale and evolution of late Cenozoic magmatism within the Caucasian segment of the alpine belt

2011

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Results of the isotope geochronological studies of the Late Cenozoic magmatism of Caucasus have been considered. The Neogene-Quaternary volcanic activity is found to have evolved during the last 15 m. y. being most intensive in the Middle-Late Pliocene. Within separate neovolcanic areas of the Cauca sus region, magmatism was of a clearly discrete character when intense eruption periods interchanged with prolonged (up to several million years) times of quiet conditions. Four stages of young magmatism of the Cau casus are recognized: the Middle Miocene (15-13 Ma), the Late Miocene (9-5 Ma), the Pliocene (4.5-1.6 Ma), and the Quaternary (less than 1.5 Ma). However, for certain areas the time limits of these stages were shifted relative to each other and overlap the whole age range from the mid Miocene to the end of the Quaternary period. Therefore, within the collision zone, the Neogene-Quaternary magmatism evolved almost continu ously during almost the last 9 m. y., but in the time interval of 13-9 Ma in the Caucasian segment, volcanic activity was possibly low. No evidence of directed lateral migration of volcanic activity within the entire Cau casus region was found. At the same time, in the Lesser Caucasus the young magmatism commenced earlier (~15 Ma), compared to the Greater Caucasus (~8 Ma).

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