THE FUMAROLE «LEDOVAYA» OF ICHINSKY VOLCANO (KAMCHATKA) IN 2020

Ichinsky volcano is the largest volcanic structure of the Sredinny Range of Kamchatka. The manifestation of fumarole activity on the northern slope of the volcano is known since 1956. 64 years after the discovery of the Ledovaya fumarole, it was inspected with a quadrocopter. It was found that the fumarole is located at an altitude of 2725 m and is a large funnel up to 60 m in size, covered with snow in the middle part. In the upper part of the funnel there is a hole in the ice mass 9.8 m in diameter, with vapor-gas clouds rising up to 5–10 m above its edge.. The walls of the ice well are covered with a grayish-yellow fouling of sublimations. The authors believe that the probable temperature of the vapor-gas mixture of fumaroles at the outlet of the volcano rocks is significantly higher than 100° C.

A model for the origin of Al-rich efflorescences near fumaroles, Melos, Greece: enhanced weathering in a geothermal setting

Efflorescences in the geothermal field of SE Melos, Greece, contain significant amounts of hydrated Al sulphate, alunogen, which could represent the Melian alumen exploited in Roman times and commended by Pliny. The efflorescences at subaerial fumaroles are explained as follows: Sulphur crystallizes on oxidation of H2S emanating from depth. Weathering produces sulphuric acid enhancing groundwater alteration of volcanic rocks. The high geothermal gradient and arid climate stimulate efflorescences. Salts are recycled during wet and dry weather leading to Al-enrichment on loss of Fe(II,III) and other cations. δ34S‰ V-CDT values for sulphur in fumarole sublimates, solfatara soils and ‘veins’ range from —0.3 to 6.4‰, mean 3.8‰ (n = 8) while Al, Ca and Mg-sulphates in diverse settings range from —4.1 to 6.8‰ (n = 16). The values for sulphur indicate that the initial H2S had an igneous source and the signature is largely inherited by the sulphates.This study aims to underpin research into the exploitation of industrial minerals in the Roman period. When searching for early alumen workings, areas with evidence of acid sulphate alteration (white rocks) and sulphurous fumarole activity should be investigated.

Tertiary Fumaroles on the Island of Raasay, Inverness-shire

Three large pipes of brecciated Torridonian sediments set in matrices of calcite and calcareous mudstone occur on the island of Raasay. Previous work has shown that these structures may be due to explosive fumarole activity during the Tertiary volcanic episode. A recent study of the Torridonian stratigraphic succession has made it possible to demonstrate that there was considerable variation in the amount of vertical collapse of the local country rock caused by the explosions. In one vent local fracturing and brecciation took place with no downward movement; in another it is possible to show that Torridonian boulders tumbled at least 350 metres down into the throat of the fumarole. The amount of vertical collapse increases from vent to vent southwards towards the Cuillins volcanic centre.These vents are of particular interest for two reasons. Though clearly of volcanic origin they contain no volcanic material. Secondly, the carbonate matrix of analogous structures is generally believed to be due to the hydrothermal solution of underlying limestone beds. The latter are absent in these examples and the carbonate material seems to be solely of volcanic origin.