Complete Genome Sequence of a Chemolithoautotrophic Iron-Oxidizing Bacterium, Acidithiobacillus ferrooxidans Strain NFP31, Isolated from Volcanic Ash Deposits on Miyake-Jima, Japan

The genome sequence of Acidithiobacillus ferrooxidans strain NFP31, which is a chemolithoautotrophic iron-oxidizing bacterium that inhabits acidified volcanic deposits on Mount Oyama, Miyake Island (Miyake-jima), Japan, was determined to identify the genetic characteristics associated with pioneer microbes in newly placed pyroclastic deposits.

Selected Crater and Small Caldera Lakes in Alaska: Characteristics and Hazards

This study addresses the characteristics, potential hazards, and both eruptive and non-eruptive role of water at selected volcanic crater lakes in Alaska. Crater lakes are an important feature of some stratovolcanoes in Alaska. Of the volcanoes in the state with known Holocene eruptive activity, about one third have summit crater lakes. Also included are two volcanoes with small caldera lakes (Katmai, Kaguyak). The lakes play an important but not well studied role in influencing eruptive behavior and pose some significant hydrologic hazards. Floods from crater lakes in Alaska are evaluated by estimating maximum potential crater lake water volumes and peak outflow discharge with a dam-break model. Some recent eruptions and hydrologic events that involved crater lakes also are reviewed. The large volumes of water potentially hosted by crater lakes in Alaska indicate that significant flowage hazards resulting from catastrophic breaching of crater rims are possible. Estimates of maximum peak flood discharge associated with breaching of lake-filled craters derived from dam-break modeling indicate that flood magnitudes could be as large as 103–106 m3/s if summit crater lakes drain rapidly when at maximum volume. Many of the Alaska crater lakes discussed are situated in hydrothermally altered craters characterized by complex assemblages of stratified unconsolidated volcaniclastic deposits, in a region known for large magnitude (>M7) earthquakes. Although there are only a few historical examples of eruptions involving crater lakes in Alaska, these provide noteworthy examples of the role of external water in cooling pyroclastic deposits, acidic crater-lake drainage, and water-related hazards such as lahars and base surge.

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.

Recently Discovered Thick Bentonite Bed Hosted by the Lithothamnium Limestones (Badenian) in the Polish Part of the Carpathian Foredeep: The Evidence for Volcanic Origin

In this paper, we discuss the hypothesis on the volcanic origin of the precursor sediments for a thick (0.6 m) clay bed, hosted by the sequence of lithothamnium limestones of the Pińczów Formation. Combined X-ray powder diffraction, imaging methods (optical and electron microscopy), and chemical analysis were used to document the volcanic markers, which were preserved in the rock studied. The results obtained show that the clay bed discussed is bentonite in origin. This bentonite, which can be called Drugnia Rządowa bentonite, is composed almost entirely of montmorillonite with little admixtures of quartz and biotite. A small amount of calcite is present, but only in the top of the bed. Despite that, the bentonite contains nothing but clay material—it is a model example of entirely altered pyroclastic rock, which retains texture originally developed in volcanic glass fragments and reveals the preserved original features of the precursor fallout pyroclastic deposits (rhyolitic in character). The thick bentonite beds, discovered for the first time within the Badenian lithothamnium limestones of the Pińczów Formation, can be considered as a record of a violent, explosive volcanic event related to the closure of the Outer Carpathian basin and the development of the Carpathian Foredeep.

Human communities living in the central Campania Plain during eruptions of Vesuvius and Campi Flegrei

Archaeological and volcanological studies have revealed that eruptions of Neapolitan volcanoes have conditioned human settlement patterns since prehistoric times. The occurrence of high intensity explosive eruptions, interspersed with long periods of quiescence, has characterized the last 10 ka of activity of these volcanoes. Geoarchaeological studies, carried out in advance of investigations for the construction of the Rome-Naples and the new Naples-Bari railway lines, have made possible a detailed reconstruction of human presence in the central part of the Campania Plain up to the coastal strip, between the late Neolithic and the late Bronze Age. The examined chronological interval includes sequences of pyroclastic deposits erupted by both Campi Flegrei and Somma-Vesuvius, and paleosols with evidence of anthropic frequentation. Altogether, the geoarchaeological data have provided a detailed picture of human settlement and activities through time with a particular focus on a long period of quiescence of the two volcanoes and also during their intense activity.

Volcaniclastic lacustrine sedimentation in the Pleistocene Guayllabamba intermontane basin in the Ecuadorian Andes

In this work, we present the description of the sedimentary fill of a well-exposed lacustrine succession in the Ecuadorian Andes. The Guayllabamba basin is an intermontane basin located in the Andean range of Ecuador, and part of its sedimentary history is represented by a volcanically-influenced ∼100 m thick lacustrine unit of the Pleistocene age. We create a stratigraphic cross-section from the eastern to western lake margins and identify nineteen facies that were used to carry out a paleoenvironmental reconstruction. The Guayllabamba paleolake was developed in a tectonic depression surrounded by volcanoes and it was filled by sediments derived from the erosion of the volcanic edifices, the reworking of unconsolidated pyroclastic deposits, and deposition of pyroclastic currents into the lake. The lake shows a deepening trend, passing from shallow deltaic sedimentation to varved diatomites with turbidites. Abundant ash-fall beds, monolithological pumiceous deltaic sequences, and pumice-dominated thick ignimbrites show the impacts of volcanism on lacustrine sedimentation within this basin. Soft-sediment deformation and gravity flow deposits are common due to the intrabasinal tectonic activity and to the intrusion of a lava body. Aulacoseira-rich diatomites dominated the background lake sedimentation. The outcrops of the Guayllabamba basin are outstanding examples of the interaction between volcaniclastic and lacustrine sedimentation.