Geology, Petrology and Amazing Geoforms of the Late Cenozoic Volcanic Province Erusheti Plateau (Lesser Caucasus) Georgia

These Erusheti Plateau is an integral part of the volcanic highland of Southern Georgia. It is located northern part of the Lesser Caucasus in the convergence zone of the Afro-Arabian and Eurasian lithosphere tectonic plates. The territory is almost totally covered with strong volcanic and volcano-sedimentary formations of Goderdzi suite with different lithologies and facies. The suite is formed in the Late Miocene - Early Pliocene Age, about from 11.8±4 to 13.6±3.1 Ma. Erusheti Plateau overall, are not characterized by many centers of eruption; Here we discuss eruption histories of the large polygenic volcanic massive Dokhuz-Puar and a monogenic volcano Datvistskaro are clearly seen among the volcanogenic structures of Erusheti Plateau. The eruption products of Dokhkuz-Puar volcano are dacitic-containing tuff-breccias and lava flows. The activity of Datvistskaro volcano was expressed only by the eruption of pyroclastic deposits containing andesite basalts. The main constituent minerals are: plagi­oclase and hornblende mega-crystals in dacites; augite-olivine and base plagioclase – in andesite basalts. With their geochemical properties, all the rocks of the rocks of a calc-alkali series. Dacites and andesite-basalts do not feed from a common magmatic source and consequently, are not the product of differentiation of the same magma. The work is the first to describe the natural amazing natural geoforms developed in pyroclastolites of Datvistskaro volcano: gigantic stone columns, mushroom-shaped stone caps and stone lances.Should be noted that no detailed mine­ralogical-petrological study of the rocks common in the study area has done to date. The main purpose of the given work is filling this gap.

Discussion on ‘Acheulian and Tephra from Upland Western Maharashtra, (Deccan Volcanic Province), Peninsular India’, by Deo et al. 2021 (SP 515)

Acheulean artefacts are widely known from archaeological complexes in India and commonly comprise handaxes, picks and cleavers. These provide information on human occupation and evolution across India, and have been the subject of much research on stone technology. In some of these sites, artefacts are associated with a Pleistocene volcanic ash layer derived from the Toba caldera in Sumatra, but various studies have derived a wide range of ages from this deposit leading to differing schools of thought as to the age of the tephra. Recent trace element, fission track and mineralogical studies (since 2011), have enabled accurate recognition of each Toba eruptive unit across their fall out, but these approaches continue to be overlooked in some studies where artefacts and Toba tephra co-exist in India. This leads to significant errors in tephra identification, and thus hampers any derived age interpretations. Most recently, this includes the study by Deo et al. (2021) who, in Geological Society Special Publication 515 (Tiwari et al., 2021), report ages for artefacts and tephra from two sites in the Deccan Volcanic Province which have become pivotal in many arguments, namely Morgaon and Bori. Here we address these issues and reiterate the methods for identification of the three main Toba tephra deposits.

Reply to Discussion on ‘Acheulian and Tephra from Upland Western Maharashtra, (Deccan Volcanic Province), Peninsular India’, by Deo et al. 2021 (SP 515)

We acknowledge with gratitude the comments by Pearce et al on our paper on the Acheulian and Tephra in the Deccan Volcanic Province in Peninsula India with reference to the sites of Bori and Morgaon. These comments are appreciated, and have been duly taken under advisement.