Fig 7 - uploaded by Ivan P Savov
Content may be subject to copyright.
Sketch cross sections of the Syunik volcanic highland. The lines of section L1 and L2 are shown in Fig. 2. Volcanism prior to 1 Ma was dominated by large polygenetic volcanoes, of which there were at least 2, possibly of multiple generations. Mafic-intermediate monogenetic volcanism younger than 1 Ma overlies the polygenetic volcanoes. Individual scoria cones may be associated with lava flow fields of variable sizes. Dykes, sills and conduits must have supplied these vents, and a couple of these are illustrated for the Holocene and rhyolite volcanism. Monogenetic felsic volcanism also occurred in the last 1 Myr, and was localised in the north of the Syunik volcanic highland (line L1). Without more borehole data, the deeper parts of the cross section are speculative. The intrusive unit which does not outcrop at the surface is shown on the basis of one of the three geothermal boreholes (Gilliland et al., 2018).
Source publication
The post-collisional Syunik and Vardenis volcanic highlands, located in the southern Lesser Caucasus mountains (part of the Arabia-Eurasia collision zone) are host to over 200 monogenetic volcanoes, as well as 2 large Quaternary polygenetic volcanoes in the Syunik highland. The latter are overlain by lavas from the monogenetic volcanoes, suggesting...
Context in source publication
Context 1
... in the diatomite sediments (1.24 ± 0.03 and 1.16 ± 0.02 Ma; Section 2.1). These tephra layers could then be sourced from local Plinian eruptions, and may in fact be the youngest marker of polygenetic volcanism in Syunik. After 1 Ma the polygenetic edifices were covered by younger monogenetic volcanoes and their associated lava flow fields (Fig. 7). These lava flows were predominantly mafic-intermediate in composition, except for a small area in the north of Syunik which includes rhyolite domes and flows (Figs. 2 and ...
Citations
... Ma); 3. Middle-Late Pleistocene (0.9-0.01 Ma) (Lebedev et al., 2021). The majority of lavas in all intervals is represented by mildly alkaline rocks with compositions varying from trachybasalts to trachydacite, and locally to rhyolites (Arutyunyan et al., 2007;Karapetyan and Adamyan, 1973;Lebedev et al., 2021;Lebedev et al., 2018;Meliksetian, 2018;Sugden et al., 2021). The Pliocene volcanism, accompanied by the overall uplift of the region, has been attributed to the delamination of the SAB lithospheric mantle weakened by asthenospheric upwelling (Lebedev et al., 2021;Lechmann et al., 2018;Rolland, 2017;Sosson et al., 2010), to amphibole dehydration melting (Allen et al., 2013), or various combinations of these factors (Neill et al., 2015;Sugden et al., 2019). ...
Cenozoic faunal exchanges between Europe, Asia, Africa and America played a key role in shaping modern-day Eurasian ecosystems with dispersal pathways controlled by the dynamics of natural palaeogeographic barriers (e.g., deserts, isthmuses, large water bodies, etc.). The South Caucasus is a mountainous region between Asia and Europe, which served as an important dispersal route during the late Cenozoic for the intercontinental exchanges of diverse terrestrial vertebrates. The Pliocene geology of this region is dominated by volcanic and volcaniclastic deposits that are generally not favourable for fossil preservation. However, a few rich fossil vertebrate faunas do occur although they lack comprehensive palaeoenvironmental and age constraints. In this paper, we present an integrated study of the stratigraphy and palaeontology of the Jradzor section located in the Gegham volcanic province of Armenia, to improve knowledge of late Cenozoic dispersal pathways. The 57-m-thick succession comprises 19 fossiliferous horizons with at least 48 identified vertebrate taxa (excluding birds). The palaeoenvironmental reconstruction suggests that the succession was deposited within a short-lived dammed lake that was subject to pyroclastic density flows, and later evolved into soil catenas. Taphonomic observations indicate that pyroclastic flows caused a high mortality of small-size vertebrates in most fossiliferous horizons, while a catastrophic lahar buried the large vertebrate fauna. Multiproxy dating places the studied section between 4.3 and ~ 3.03 Ma and the mammalian fauna correlates to the MN15. Comparison with similar age localities from across the region shows that Jradzor comprises the most continuous Pliocene succession with the highest number of fossil taxa and fills the MN15 interregional gap. The rich fossil vertebrate faunas have Asian and primarily European affinities. Findings show that the South Caucasus was a significant dispersal route for terrestrial vertebrates between Europe, Asia and Africa, and is of crucial importance for understanding Eurasian palaeogeography.
... Ma); 3. Middle-Late Pleistocene (0.9-0.01 Ma) (Lebedev et al., 2021). The majority of lavas in all intervals is represented by mildly alkaline rocks with compositions varying from trachybasalts to trachydacite, and locally to rhyolites (Arutyunyan et al., 2007;Karapetyan and Adamyan, 1973;Lebedev et al., 2021;Lebedev et al., 2018;Meliksetian, 2018;Sugden et al., 2021). The Pliocene volcanism, accompanied by the overall uplift of the region, has been attributed to the delamination of the SAB lithospheric mantle weakened by asthenospheric upwelling (Lebedev et al., 2021;Lechmann et al., 2018;Rolland, 2017;Sosson et al., 2010), to amphibole dehydration melting (Allen et al., 2013), or various combinations of these factors (Neill et al., 2015;Sugden et al., 2019). ...
The intercontinental faunal dispersions played a key role in the shaping of the modern-day Eurasian ecosystems. The Cenozoic faunal exchanges between Europe, Asia, Africa and America were controlled by the dynamics of natural palaeogeographic barriers (e.g., deserts, isthmuses, large water bodies, etc.) leading to repetitive closures and openings of the faunal migration paths. One of such remarkable barriers is the Arabian Desert, whose hyperaridification between 5.6 and 3.3 Ma ceased the African-Eurasian faunal exchanges. Except for geochemical data and climate modelling, reflection of this event in the Eurasian fossil record is still unclear due to the lack of representative and well-dated Pliocene fossil localities. The South Caucasus is a mountainous region between Africa, Asia and Europe that in the late Cenozoic served as an important land bridge for the intercontinental dispersal of different vertebrate groups, including Miocene apes and early humans. The Pliocene geological record of the South Caucasus is dominated by volcanic and volcaniclastic deposits, some of which are remarkably rich in fossil vertebrates. Here, we present an integrated stratigraphy and palaeontology of the Jradzor section located in the Gegham volcanic province of Armenia. The 57-m-thick succession comprises 19 fossiliferous horizons with at least 48 identified vertebrate taxa (excluding birds). The palaeoenvironmental reconstruction suggests that the locality was formed as a short-lived dammed lake that later became a subject for pyroclastic density currents and paedogenic intervals. Taphonomic observations indicate a high-mortality of small-size vertebrates in most of fossiliferous horizons to be caused by pyroclastic flows while the large vertebrate fauna was buried by a catastrophic lahar. The multiproxy dating places the studied section between 4.3 and ~3.03 Ma. The revealed mammalian fauna correlated to the MN15 zone. Comparison with similar age localities from the region shows that Jradzor is the only continuous Pliocene locality with the highest number of fossil taxa that fills the MN15 interregional gap. The so far revealed rich fossil vertebrate faunas have Asian and primarily European affinities. The South Caucasus is an essential tying point between Europe, Asia and Africa and, thus, become of global importance for palaeobiogeographic studies.
... Located between the Black and Caspian Seas, the Lesser Caucasus was formed by the collision of the Arabian and Eurasian plates since the Neogene (Mitchell and Westaway, 1999;Sugden et al., 2021;Fig. 1). ...
Pollen-based vegetation change has been inferred from sediments in Kalavan Red Lake. This small lake is placed in the beech-oak-hornbeam forest, about three kilometres away from archaeological remains. It has the potential to document the Holocene forest history and climate and human impacts on the Lesser Caucasus. However, this lake happens to be formed by a large landslide.
Pollen and XRF analysis are provided over the last 3800 years. The basal age of the Kalavan sediment approximates the landslide age. This created a not vegetated slope including the lake catchment. Erosion and sedimentation processes brought coarse and heavy minerogenic elements, declining with the catchment revegetation by tall-grassland. This shift in the sedimentation continues, suggesting less erosion in the catchment when an admixture of Quercus and grasslands settled. Starting from 2000 cal. BP, arboreal pollen increases successively thanks to the step afforestation of Quercus, Carpinus orientalis and Fagus.
The comparison with available pollen reconstruction illustrates the uniqueness of the vegetation dynamic recorded at Kalavan. However, the duration of this succession is also questionable. An intermediate hypothesis is proposed: the Kalavan's dynamic is first initiated by the landslide with the tall-grass development, then paced by the regional vegetation dynamic.
Linking vegetation history and erosion with regional climate and archaeological data helps to evidence short-term climate change and human impact. Antique arid phase (2000–1600 cal. BP), the Medieval Warm Period and Little Ice Age affect the vegetation, while demography variations during the Medieval period and Modern Age are shown by pastoral activity.
The territory of the Republic of Armenia (RA) stands out in its complex geological structure and diversity of formations due to its complex geodynamic history and the country being located in the axial part of the Arabian and Eurasian continental collision zone. The selected geohazard-related geosites of regional and international interest allow us to propose the creation of a geopark, focused on geohazards. The Armenian geohazard-related geopark will encompass 26 geosites with various geological hazards concerning active faults and surface ruptures, recent volcanism and related lava flows, stratigraphic evidence of mass extinction events, saturated with carbon dioxide subaquatic gas emissions related to buried active fault segment and a borehole of a pulsating water fountain, coastal transgression and regression of various intervals from several thousand to about three hundred million years, active geodynamic processes and related ophiolite obduction, earthquake-related active slope processes, causing destruction and deformation of historical monuments, among others. Some geosites are exceptionally rich in archaeological monuments affected by geological phenomena. From the perspective angle, the results of this study will benefit management of the land environment, historical and cultural heritage, raising awareness of natural hazards and increasing population resilience. The study’s results can have wide-ranging implications, including improved geoheritage education, development of conservation ethics, better land management practices, enhanced understanding of historical and cultural heritage, increased awareness of natural hazards, and the promotion of sustainable development through the proposed Armenian Geopark.
It has been 25 years since the publication of the monograph L’obsidienne au Proche et Moyen Orient: Du volcan a` l’outil (Cauvin et al., 1998) and, within it, Poidevin’s (1998) chapter that summarized all available geochemical and geochronological data for obsidian sources in Turkey and the Caucasus. It was a highly valuable resource to those of us working on Near Eastern obsidian sourcing in the early 2000s; however, an update is long overdue. Poidevin (1998) compiled 229 analyses for obsidian sources in eastern Turkey and the Caucasus, and while he recognized the importance of independent analytical data, he was also frustrated that the few available data obscured real differences in obsidian composition versus variation among the different analytical facilities. Today we are closer to Poidevin’s (1998) goal. Here I summarize more than 7300 elemental analyses for 58 geochemically distinct obsidian sources. For example, Poidevin (1998) had just two analyses for Meydan Dag ̆, a highly important obsidian source, whereas here I report consensus values for 22 elements in Meydan Dag ̆ obsidian based on 423 analyses from 25 independent techniques and laboratories. Not all 58 of the known obsidian sources within this region, however, have been so well characterized, and it is clear that there remains work to be done.
Quaternary volcanic centres north of the Bitlis-Zagros suture in Turkey, Iran and the Caucasus represent both volcanic hazards and potential or actual geothermal energy resources. Such challenges and opportunities cannot be fully quantified without understanding these volcanoes' petrogenesis, geochronology and magmatic, tectonic or other eruption triggers. In this preliminary study, we discuss the age and geology of the Karkar monogenetic volcanic field in Syunik, SE Armenia. The ∼70 km² field is close to Armenia's only geothermal energy test drilling site. Fissure-fed trachybasaltic andesite to trachyandesite lavas erupted on a trans-tensional segment of the Syunik branch of the Pambak-Sevan-Syunik Fault, where previous studies suggested a Holocene age for the youngest eruptions. Here, high-resolution duplicate ⁴⁰Ar/³⁹Ar dating of 7 groundmass separates provided inverse isochron ages ranging from 7.4 ± 3.6 ka and 7.9 ± 2.9 ka to 353 ± 20 ka (2σ). Each lava flow displays petrographic and whole rock geochemical patterns consistent with melting of subduction-modified lithospheric mantle and extensive evolution within the crust involving fractional crystallisation and mixing of magma batches. Data confirm that volcanic activity related to the Syunik Fault overlapped with Palaeolithic to Bronze Age human occupation and remains a minor lava inundation hazard. Further geochemical work will allow constraint of the depth and timescales of magma storage. Both Karkar and the area around Porak volcano, which lies 35 km N of Karkar on the Syunik Fault, might be considered for future geothermal energy developments.
