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Geological (volcanological) map of Javakheti volcanic area (Lesser Caucasus). Edition of 2016. Version 2.
Abstract
NEW VERSION (2016-2) OF "Geological (volcanological) map of Javakheti volcanic area (Lesser Caucasus)" IS AVAILABLE NOW.
Two-layer geological map of the Javakheti neovolcanic area, Lesser Caucasus (Southern Georgia, Northern Armenia, North-Eastern Turkey), the region with a large manifestation of Neogene-Quaternary volcanism. Scale 1/200000. Compiled by V.A. Lebedev (IGEM RAS) ©. File is in PSD (Photoshop) format. Layers: topography, geology.
Version of 2016, #2 (01/09/2016).
The map will be updated constantly after publishing of new data.
Reference should be given as: Lebedev V.A. Geological map of Javakheti volcanic area (Lesser Caucasus), 1/200000, ed.2015-2. Moscow, IGEM RAS. // V.A. Lebedev, S. N. Bubnov, O. Z. Dudauri, G. T. Vashakidze. Geochronology of Pliocene volcanism in the Dzhavakheti highland (the Lesser Caucasus). Part 2. Eastern part of the Dzhavakheti highland. Regional geological correlation // Stratigraphy and Geological Correlation. 2008. V.16(5). P.553-574.
... They reported lava flows with reverse polarity in the middle part of the sequence and proposed a magnetostratigraphic correlation between the Thoki and Tchunchka sites. Then, Goguitchaichvili et al. (2000) carried Lebedev et al., 2008Lebedev et al., , 2016. 1 -Late Quaternary volcanic rocks (andesites and dacites) of the Samsari ridge (<800 ka); 2-10 Pliocene -Early Quaternary volcanic rocks of Akhalkalaki Formation (2 -basic lavas 1.75-1.50 Ma, 3 -basic lavas 2.15-1.95 ...
Well-exposed lava sequences with available geochronological information may provide invaluable information on the fine characteristics of the Earth's magnetic field variation. A paleomagnetic study has been performed on twenty Pleistocene age, sub-horizontal lava flows in the Javakheti Highland (Lesser Caucasus). The sequence is formed by calc-alkaline basaltic lavas and is divided by a thin sedimentary layer in its upper part. We obtained two new radiometric ages: an age of 1.93±0.09 Ma for the flows below the sedimentary layer and 1.78±0.11 Ma for the upper part of the sequence. Thermomagnetic susceptibility vs. temperature curves indicate that remanence is carried by ferrimagnetic minerals like magnetite, titanomagnetite or titanomaghemite. Reliable paleomagnetic results could be obtained from all 20 analyzed flows, yielding the following reverse-polarity mean direction for the whole sequence: inclination I =-61.5°and declination D =200.1° (N = 20; α95 =3.1°; k=114). This direction does not agree with the expected one. The discrepancy can be explained by an apparent clockwise 17.1 ± 6.1° vertical-axis rotation. Alternatively, such moderate deviation may be due to some unstable geomagnetic regime or undersampled paleosecular variation. Isotope ages obtained in the present study indicate that the Toloshi sequence emplaced during the normal-polarity Olduvai subchron, but palaeomagentic results indicate a reverse-polarity magnetization. At the same time, the analysis of virtual geomagnetic pole (VGP) scatter indicates that the Toloshi sequence was probably formed during a short time, insufficient to average paleosecular variation. These results suggest that the Olduvai subchron is probably disrupted by a short reverse-polarity episode.
... Basic lavas were erupted in the southern part of the Javakheti Highland and Upper Akhuryan Basin in the Gelasian . As a result, lavas filled the Akhurian paleo-valley and spread to the northern part of the Shirak Basin (Lebedev et al., 2008(Lebedev et al., , 2015. In the Calabrian and Middle Pleistocene, the volcanic activity renewed in the southern surrounding of the Shirak Basin, that is, the basalts near the Digor town in Turkey have the age of ∼1.6-1.3 ...
The area under study belongs to the Armenian part of the Armenian volcanic Highland. Previous investigations (Milanovsky, 1968; Trifonov et al., 2014, 2016; Trifonov, 2016) revealed that mountain systems of the Arabia-Caucasus region as well as other segments of the Alpine-Himalayan Belt rose significantly and rapidly during the Late Miocene and particularly the Pliocene and Quaternary. Intermountain and surrounding basins were partly involved into the uplift and partly subsided within a short period of time (Trifonov et al., 2012a; Trifonov, 2016). The origin of many of these basins was related to the Late Cenozoic fault motions and other manifestations of the collisional plate interaction (Trifonov et al., 2017). At the same time, some basins of the Armenian volcanic Highland do not demonstrate apparent relations to the collisional faulting. Milanovsky (1968) attributed their origin to transformations in deep layers of the lithosphere expressed in volcanism. The present paper is devoted to examination of this hypothesis through the example of the Shirak Basin in NW Armenia. New data on stratigraphy and age of the Shirak Basin Quaternary cover as well as its tectonic deformation and correlation with surrounding volcanism are represented. The origin of the basin is discussed with account of new data.
... SB: angular scatter or ASD, SU: upper confidence limit, SL: lower 984 confidence limit. 985 986 [ Lebedev et al., 2008;Calvo-Rathert et al., 2013;Lebedev, 2015]. 1 -Quaternary volcanic 992 rocks (andesites and dacites) of the Samsari ridge (800 -<30 ka); 2-10 Pliocene -Early 993 ...
We report a detailed paleomagnetic study on two Plio‐Pleistocene lava flow sequences from the Djavakheti Highland, Lesser Caucasus. The Korkhi sequence is composed of two volcanic successions of distinct age (1.9 and 3.1 Ma), while the Apnia sequence was emplaced between 3.8 and 3.1 Ma according to available radiometric datings. Normal, reverse and intermediate polarities have been determined from both sequences. Mean directions of the normal and reverse polarity groups for each section do not match the expected field direction, but the possibility of tectonic rotations has been dismissed. A composite analysis of paleomagnetic directions, of virtual geomagnetic pole (VGP) scatter and available paleointensity results from a previous study, allow the interpretation of the observed paleomagnetic results. In the Apnia sequence, both a short recording time unable to average paleosecular variation (PSV) and an anomalous Earth magnetic field (EMF) record are responsible for the observed paleomagnetic directions. According to paleomagnetic results and radiometric ages, this sequence most probably records the reverse to normal polarity transition C2Ar to C2An‐3n. The upper Korkhi subsequence yields an anomalous EMF record, reflecting a transitional time interval. Paleomagnetic results and available absolute ages suggest that this subsequence either records transition C2r‐1r to Olduvai or Olduvai to C1r‐2r. The lower Korkhi subsequence registers a normal polarity interval within the Gauss chron, reflecting a stable stage of the EMF.
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