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Journal articles on the topic 'Volcanic'
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1
Yanev, Yotzo, Vlastimil Konečný, Alexandra Harkovska, Sergiu Peltz, and Pál Gyarmati. "Petrochemical characterisation of the Late Alpine orogenic acid volcanism of the Carpathian-Balkan area." Geologica Balcanica 25, no. 1 (February 28, 1995): 3–12. http://dx.doi.org/10.52321/geolbalc.25.1.3.
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Late Apine orogenic volcanism appears immediately after the main phase of folding and thrusting in the Carpathian-Balkan area. The age of the volcainic manifestations is Priabonian-Oligocene (after Ilirian phase) in the Balkan segment and Miocene-Pliocene (after Savian phase) in the Carpathian segment, respectively. Most of the acid volcanics are formed by crustal melting, whereas a smaller part are differentiates of basaltic and intermediate magmas. The first one has higher SiO2 content than the second. K2O content increases from the North to the South: in the Carpatian segment the acid volcanics are Ca-alkaline and high-K Ca-alkaline, whereas in the Balkan segment they are high-K Ca-alkaline and shoshonitic. The Na2O content of the acld volcanics of both segments show less significant variations. The amount of K2O correlates with the thickness of the crust in the different volcanic regions. The petrochemical data of the Carpathian-Balkan acld volcanlcs permit to draw a boundary between high-K Ca-alkaline and shoshonitic series at a level of K2O=4.75 wt % (at 70 wt % SiO2) and K2O=4.9 wt % (at 78 wt % SiO2) in the Peccerillo & Taylor diagam.
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Ludden, John, Claude Hubert, and Clement Gariépy. "The tectonic evolution of the Abitibi greenstone belt of Canada." Geological Magazine 123, no. 2 (March 1986): 153–66. http://dx.doi.org/10.1017/s0016756800029800.
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AbstractBased on structural, geochemical, sedimentological and geochronological studies, we have formulated a model for the evolution of the late Archaean Abitibi greenstone belt of the Superior Province of Canada. The southern volcanic zone (SVZ) of the belt is dominated by komatiitic to tholeiitic volcanic plateaux and large, bimodal, mafic-felsic volcanic centres. These volcanic rocks were erupted between approximately 2710 Ma and 2700 Ma in a series of rift basins formed as a result of wrench-fault tectonics.The SVZ superimposes an older volcanic terrane which is characterized in the northern volcanic zone (NVZ) of the Abitibi belt and is approximately 2720 Ma or older. The NVZ comprises basaltic to andesitic and dacitic subaqueous massive volcanics which are cored by comagmatic sill complexes and layered mafic-anorthositic plutonic complexes. These volcanics are overlain by felsic pyroclastic rocks that were comagmatic with the emplacement of tonalitic plutons at 2717 ±2 Ma.The tectonic model envisages the SVZ to have formed in a series of rift basins which dissected an earlier formed volcanic arc (the NVZ). Analogous rift environments have been postulated for the Hokuroko basin of Japan, the Taupo volcanic zone of New Zealand and the Sumatra and Nicaragua arcs. The difference between rift related ‘submergent’ volcanism in the SVZ and ‘emergent’ volcanism in the NVZ resulted in the contrasting metallogenic styles, the former being characterized by syngenetic massive sulphide deposits, whilst the latter was dominated by epigenetic ‘porphyry-type’ Cu(Au) deposits.
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Smellie, John L., Kurt S. Panter, and Jenna Reindel. "Chapter 5.3a Mount Early and Sheridan Bluff: volcanology." Geological Society, London, Memoirs 55, no. 1 (2021): 491–98. http://dx.doi.org/10.1144/m55-2018-61.
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AbstractTwo small monogenetic volcanoes are exposed at Mount Early and Sheridan Bluff, in the upper reaches of Scott Glacier. In addition, the presence of abundant fresh volcanic detritus in moraines at two other localities suggests further associated volcanism, now obscured by the modern Antarctic ice sheet. One of those occurrences has been attributed to a small subglacial volcano onlyc.200 km from South Pole, making it the southernmost volcano in the world. All of the volcanic outcrops in the Scott Glacier region are grouped in a newly defined Upper Scott Glacier Volcanic Field, which is part of the McMurdo Volcanic Group (Western Ross Supergroup). The volcanism is early Miocene in age (c.25–16 Ma), and the combination of tholeiitic and alkaline mafic compositions differs from the more voluminous alkaline volcanism in the West Antarctic Rift System. The Mount Early volcano was erupted subglacially, when the contemporary ice was considerably thicker than present. By contrast, lithologies associated with the southernmost volcano, currently covered by 1.5 km of modern ice, indicate that it was erupted when any associated ice was either much thinner or absent. The eruptive setting for Sheridan Bluff is uncertain and is still being investigated.
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Smellie, John L. "Chapter 3.2a Bransfield Strait and James Ross Island: volcanology." Geological Society, London, Memoirs 55, no. 1 (2021): 227–84. http://dx.doi.org/10.1144/m55-2018-58.
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AbstractFollowing more than 25 years of exploration and research since the last regional appraisal, the number of known subaerially exposed volcanoes in the northern Antarctic Peninsula region has more than trebled, from less than 15 to more than 50, and that total must be increased at least three-fold if seamounts in Bransfield Strait are included. Several volcanoes remain unvisited and there are relatively few detailed studies. The region includes Deception Island, the most prolific active volcano in Antarctica, and Mount Haddington, the largest volcano in Antarctica. The tectonic environment of the volcanism is more variable than elsewhere in Antarctica. Most of the volcanism is related to subduction. It includes very young ensialic marginal basin volcanism (Bransfield Strait), back-arc alkaline volcanism (James Ross Island Volcanic Group) and slab-window-related volcanism (seamount offshore of Anvers Island), as well as volcanism of uncertain origin (Anvers and Brabant islands; small volcanic centres on Livingston and Greenwich islands). Only ‘normal’ arc volcanism is not clearly represented, possibly because active subduction virtually ceased atc.4 Ma. The eruptive environment for the volcanism varied between subglacial, marine and subaerial but a subglacial setting is prominent, particularly in the James Ross Island Volcanic Group.
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Tripathi, C. "Volcanism in Gondwanas." Journal of Palaeosciences 36 (December 31, 1987): 285–89. http://dx.doi.org/10.54991/jop.1987.1587.
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In India the Lower Permian event is marked by a major volcanic episode in the Himalayan belt and rift faulting in the Peninsula which gave rise to various Gondwana basins. The Lower Cretaceous major volcanic episode represented by the Rajmahal Trap represents the termination of Gondwana sedimentation. Lower Permian volcanism is represented by the Panjal Volcanics in Kashmir Basin and its equivalent, the Volcanics in Spiti-Zanskar Basin and Rotung Volcanics (Abor Volcanics) in Arunachal Pradesh. In Karakarom Basin of Ladakh, volcanism is associated with Changtash and Aqtash formations of Permian age.
The Agglomeratic Slates in Kashmir are supposed to have originated as explosive volcanism in the form of pyroclastic which was followed later by flows of the Panjal Volcanics represented by subaqueous and subaerial tholeiitic basalt with occasional basaltic, andesitic and rhyolitic volcanics. The Agglomeratic slates are divided into two divisions, the Lower Diamicites and the Upper Pyroclastic. At the base of the Pyroclastic division and at the top of the Diamictite division, we get Eurydesma-Deltopecten Fauna of Lower Permian age. It is thus established that volcanism in Kashmir, Spiti-Zanskar and Ladakh is restricted to Lower Permian only. The sills and dykes associated with the underlying sequence in Syringothyris Limestone and Fenestella Shale in Kashmir, in Lipak and Po Formations in Spiti are related to this volcanism.
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Ganelin, A. V., E. V. Vatrushkina, and M. V. Luchitskaya. "Geochemistry and geochronology of cretaceous volcanism of Chauna region, Central Chukotka." Геохимия 64, no. 1 (January 15, 2019): 20–42. http://dx.doi.org/10.31857/s0016-752564120-42.
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New geochronological and geochemical data on the age and composition of Cretaceous volcanism of Palyavaam River basin (Central Chukotka, Chauna region) are presented. First complex is composed of rhyolites, ignimbrites and felsic tuffs of Chauna Group of Okhotsk-Chukotka volcanic belt (OCVB). Second complex is represented by volcanic rocks of latite-shoshonite series of Early Cretaceous age, distinguished as Etchikun’ Formation. Its origin is still debatable. Some researchers refer deposits of Etchikun’ Formation to magmatic stage before OCVB activity. Other authors include in Chauna Group composition. Obtained data indicate heterogeneity of Etchikun’ Fomation volcanics and allow to divide them in two groups. Andesites of the first group (Etchikun’ Formation sensu stricto) have Early Cretaceous age and belong to magmatic stage before OCVB activity. Andesites of the second group correlate in age and composition with OCVB volcanic rocks. They occur at the base of Chauna Group and indicate homodromous character of volcanism evolution in the Central-Chukotka of Okhotsk-Chukotka volcanic belt.
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Helgason, Jóhann, and Robert A. Duncan. "Stratigraphy, 40Ar–39Ar dating and erosional history of Svínafell, SE-Iceland." Jökull 63, no. 1 (December 15, 2013): 33–54. http://dx.doi.org/10.33799/jokull2013.63.033.
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The interplay of volcanism and erosion in the Svínafell massif, on the western slope of the Öræfajökull volcanic center, SE-Iceland, is traced with geological mapping, magnetostratigraphy and $^{40}$Ar–$^{39}$Ar age determinations. The volcanic strata are mainly of Quaternary age, i.e., geomagnetic chrons of lower Matuyama to upper Brunhes. The 1832 m thick sequence in Svínafell is composed of 37 discrete lithologic formations, assigned to seven volcano-stratigraphic groups beginning with the onset of volcanism in the Öræfajökull stratovolcano during lower Brunhes magnetic chron (C1n < 781 ka). A regional basin formed shortly before the initiation of volcanism, generating a depocenter for the plant-fossil bearing Svínafell sediments between 0.70 and 1.78 Ma. The Svínafell volcanic strata accumulated during a minimum of eight glacial and inter-glacial stages. We document the Svínafell erosion history and landscape evolution, including 12 erosion surfaces. Erosion has led to extended stratigraphic hiatuses and removal of thick volcanic sequences.
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McDOUGALL, IAN. "Age of volcanism and its migration in the Samoa Islands." Geological Magazine 147, no. 5 (February 10, 2010): 705–17. http://dx.doi.org/10.1017/s0016756810000038.
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AbstractPotassium–argon (K–Ar) ages on whole rock samples have been measured on lavas from the subaerial Samoa Islands, which form a broadly linear volcanic chain that extends from the ESE to the WNW for about 360 km. The Manu'a Islands near the southeast limit of the chain exhibit youthful ages, with most <0.4 Ma, in keeping with the geological observations. Tutuila consists of several volcanoes, and previous work yielded a mean K–Ar age of 1.26 ± 0.15 Ma for the shield-building volcanism. Upolu, to the WNW of Tutuila, gives a mean age of 2.15 ± 0.35 Ma for the shield-building phase, represented by the Fagaloa Volcanics, with much of the island covered by significantly younger volcanic rocks. Savai'i, further to the WNW, is dominated by youthful volcanism, extending into historic times. In a restricted area, adjacent to the NE coast of Savai'i, previously thought to have volcanic rocks correlating with the Fagaloa Volcanics of Upolu, the ages are much younger than those on Upolu, lying between 0.32 and 0.42 Ma. Considering only the subaerial volcanism from Ta'u to Upolu, but also including Vailulu'u, the volcanism has migrated in a systematic ESE direction at 130 ± 8 mm a−1 over 300 km in the last 2.2 Ma. This rate is nearly twice that obtained from GPS measurements of Pacific Plate motion of 72 mm a−1 at N64°W in this area. However, if the much older age of shield-building volcanism from the submarine foundations of Savai'i is included, the regression yields a volcanic migration rate of 72 ± 14 mm a−1, in keeping with the measured GPS rate and consistent with a hotspot origin for the island chain. This suggests that the volcanic migration rates determined from the age of subaerial volcanism can be considerably overestimated, and this is now evident in other Pacific Ocean island chains. Clearly, the ages of the main shield-building volcanism from subaerial volcanism are minima, and if the older submarine lavas can be measured, these may yield a migration rate more in keeping with current plate motions.
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Koloskov, A. V., M. Yu Puzankov, V. V. Ananiev, and D. V. Kovalenko. "BOLSHOI PAYALPAN VOLCANO (SREDINNY RANGE, KAMCHATKA). PROBLEMATIC ASPECTS OF CONVERGENCE OF ISLAND-ARC AND INTRAPLATE PETROLOGICAL AND GEOCHEMICAL SIGNATURES IN THE MAGMATIC SYSTEM." Tikhookeanskaya Geologiya 41, no. 2 (2022): 3–24. http://dx.doi.org/10.30911/0207-4028-2022-41-2-3-24.
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The paper presents the data on age, mineralogy, geochemistry, and isotope composition of rocks from the Bolshoi Payalpan Volcano (Sredinny Range, Kamchatka). We compared these data with those on the Nosichan and Belogolovsky volcanoes, located within the Belogolovsky volcanic center. The basalts of the neck and the upper lava complex of Bolshoi Payalpan are compositionally similar to the intraplate-type trachybasalts of the Belogolovsky Volcano, and the basaltic andesites of the lower lava and the cone complex are similar to the island arc rocks of the Nosichan Volcano. Analysis of the data obtained evidences that spatial and temporal manifestations of intraplate and island-arc volcanism at the Bolshoi Payalpan Volcano are not accidental, but may be a consequence of a change in the degree and depth of melting of the same deep source with the involvement of a mantle diapir. The Belogolovsky volcanic center formed in a setting of the Late Miocene-Early Pliocene rifting. Its evolution, right up to its extinction, proceeded in the same geodynamic setting with an increase in depth of the mantle source and a decrease in the degree of its melting. Rock compositions of the Lower-Middle Pliocene Nosichan Volcano remain of the island-arc type under conditions of rifting, since they are associated with the mantle reservoir located at a shallower depth, which has experienced a higher degree of melting. There is good reason for considering large volcanic centers as spontaneously-developing geological entities. As the endogenous activity dies down, the degree of melting decreases and the depth of melting increases with the replacement of island-arc volcanism by intraplate volcanism. The volcanic center becomes extinct.
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Zakharikhina, L. V., and Yu S. Litvinenko. "Volcanism and geochemistry of soil and vegetation cover of Kamchatka. Communication 2. Specificity of forming the elemental composition of volcanic soil in cold and humid conditions." Вулканология и сейсмология, no. 3 (May 14, 2019): 25–33. http://dx.doi.org/10.31857/s0203-03062019325-33.
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Volcanic soils of Kamchatka have the low contents of most the chemical elements in relation to their overall prevalence in the soils of continents and volcanic soils of Europe. Relatively increased gross contents of elements typical for volcanic rocks of medium and basic composition: Na, Ca, Mg, Cd, Mn, Co, Cu, and steadily low contents of elements characteristic of acid volcanics: La, Ce, Pr, Nd, Nb, Hf, Tl, Rb and Th, is most characteristic of the soils of different areas of the peninsula. The existing in the past and currently observed different conditions of volcanism in the previously allocated soil areas of Kamchatka determine the diversity of the chemical composition of the soils in these territories.
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Zakharikhina, L. V., and Yu S. Litvinenko. "Volcanism and geochemistry of soil and vegetation cover of Kamchatka. Communication 2. Specificity of forming the elemental composition of volcanic soil in cold and humid conditions." Вулканология и сейсмология, no. 3 (May 14, 2019): 25–33. http://dx.doi.org/10.31857/s0205-96142019325-33.
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Volcanic soils of Kamchatka have the low contents of most the chemical elements in relation to their overall prevalence in the soils of continents and volcanic soils of Europe. Relatively increased gross contents of elements typical for volcanic rocks of medium and basic composition: Na, Ca, Mg, Cd, Mn, Co, Cu, and steadily low contents of elements characteristic of acid volcanics: La, Ce, Pr, Nd, Nb, Hf, Tl, Rb and Th, is most characteristic of the soils of different areas of the peninsula. The existing in the past and currently observed different conditions of volcanism in the previously allocated soil areas of Kamchatka determine the diversity of the chemical composition of the soils in these territories.
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Asrafil, Asrafil, Teguh Hilmansyah, Muslimin U. Botjing, and Eka Yuliastri. "Mineralization Study of Volcanic Rocks in Colo Volcano Tojo Una-Una Central Celebes." Jurnal Geomine 8, no. 3 (February 19, 2021): 171. http://dx.doi.org/10.33536/jg.v8i3.705.
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Colo Volcano is an active volcano located on Una-Una Island, Tojo Una-Una Regency, Central Sulawesi Province. Volcanism and magmatism of Mount Colo are still in progress, and this has certainly triggered mineralization in volcanic rocks which is interesting for study. This research aims to reveal the mineralization characteristics of volcanic rocks in the study area. This research was conducted through investigative methods in the form of field observations and laboratory through petrographic and rock chemistry (X-Ray Defraction analysis) to reveal the presence of alteration minerals as a characteristic of mineralization. The results of this study indicate that the volcanic rocks present are tuff and volcanic breccia in the form of pyroclastic deposits associated with alluvial material and andesite rocks. Identification of alteration minerals through XRD test shows the presence of hydrothermal alteration minerals with a formed temperature of 300 ° C such as Quartz, Calcite, Clinochlore, Albite, Dickite, Andesine, and K-Feldspar which are classified into Argillic and Propylitic alteration types.
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Amigo, Alvaro. "Volcano monitoring and hazard assessments in Chile." Volcanica 4, S1 (November 1, 2021): 1–20. http://dx.doi.org/10.30909/vol.04.s1.0120.
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Volcanism in Chile occurs in a variety of tectonic settings but mostly in the context of oceanic-continental plate collision, including 92 potentially active volcanoes. There have been more than 30 documented eruptions in the last few centuries. The Servicio Nacional de Geología y Minería (SERNAGEOMIN) is a statutory agency of the Government of Chile responsible for volcano monitoring and hazard assessments across the country. After the impacts derived from volcanic activity at the end of the 20th century, SERNAGEOMIN created the Volcano Hazards Program and the Observatorio Volcanológico de Los Andes del Sur (OVDAS). Despite this effort, most volcanoes in Chile remained unmonitored. In 2008, the aftermath of the eruption of Chaitén led to a nationwide program in order to improve eruption forecasting, development of early warning capabilities and our state of readiness for volcanic impacts through hazard assessments. In the last decade responses to volcanic crises have been indubitably successful providing technical advice before and during volcanic eruptions. El volcanismo en Chile ocurre en una amplia variedad de regímenes tectónicos, aunque principalmente en el contexto de la colisión de placas. Alrededor de 92 volcanes son considerados potencialmente activos y más de 30 presentan actividad histórica documentada en los últimos siglos. El Servicio Nacional de Geología y Minería (SERNAGEOMIN) es la agencia gubernamental responsable de la evaluación de peligros y monitoreo de la actividad volcánica en el país. Como consecuencia de los impactos derivados de las erupciones volcánicas ocurridas hacia finales del siglo pasado, SERNAGEOMIN creó el Programa de Riesgo Volcánico y el Observatorio Volcanológico de los Andes del Sur (OVDAS). No obstante, a pesar de este esfuerzo la mayoría de los volcanes en Chile se mantenían sin monitoreo. Luego de los impactos derivados de la erupción del volcán Chaitén en 2008, un nuevo programa nacional fue creado con el fin de fortalecer la vigilancia y la evaluación de los peligros volcánicos en el país. En la última década, la respuesta a crisis volcánicas ha sido exitosa, proporcionando apoyo técnico en forma previa y durante erupciones.
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Seghedi, Ioan, Viorel M. Mirea, and Gabriel C. Ștefan. "Construction and Destruction of Bontău Composite Volcano in the Extensional Setting of Zărand Basin during Miocene (Apuseni Mts., Romania)." Minerals 12, no. 2 (February 14, 2022): 243. http://dx.doi.org/10.3390/min12020243.
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The Eastern part of the Miocene Zărand extensional basin witnessed the generation and evolution of the largest composite volcano in Apuseni Mts., named recently Bontău. The volcano is filling the basin at the junction between the South and North Apuseni Mountains. The Bontău Volcano is known to be active roughly between ~14–10. In spite of heavily forested and poorly exposed volcanic deposits, it was possible to identify its complex evolution. The volcano suggests an original oval-shaped edifice base currently showing a north-oriented horseshoe-shaped debris avalanche eroded crater. The early effusive volcanic activity was contemporaneous with the emplacement of individual and/or clustered volcanic lava Domes. Late-stage summit dome generation was followed by several volcanic collapses all around the volcanic edifice producing large volcanic debris avalanche deposits (DADs), accompanied by numerous debris flows all around the volcano periphery. Thick pumice pyroclastic flow deposits found below DADs at the periphery may suggest that the slope failures were proceeded by a Plinian eruption. The debris avalanche crater is the last event in the volcano evolution exposing several intrusive andesitic-dioritic bodies and associated hydrothermal and mineralization processes, most probably including the former central vent area of the volcano. The volcano proximal effusive and explosive deposits display a change in the composition of the erupting magma (increased SiO2 from 53.4% to 60.6%) that resulted in an increase of viscosity and the construction of the summit lava domes. Such domes are however only found as various size blocks in DADs. The volcanism connects with the two steps of geotectonic evolution of the Zărand Basin: The initial construction period during regional extension started ~16 Ma up to 12.3–12.1 when the Bontău volcano and surrounding domes were generated. The second period, younger than 12 Ma, corresponds to NW-SE compressional tectonics developed only in the Bontău volcano with summit dome generation and, finally, assists volcano destruction and DADs generation. Newly performed geochemical and Sr and Nd isotopic data studies attest to a calc-alkaline character and suggest an evolution via assimilation-fractional crystallization processes of a dominant MORB-like mantle source magma. Also, they confirm the amphibole (±pyroxene) andesites to be the most evolved lithology. The stepwise changes in fracture propagation in the Zărand extensional setting along with a change to more hydrated and fractionated magma favored in ~4 Myrs of the evolution of the Bontău volcano lead to multiple pulses of the longest-lived magma chamber in the whole Miocene volcanism of the Apuseni Mts.
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Ko, Kyoungtae, Sungwon Kim, and Yongsik Gihm. "U-Pb Age Dating and Geochemistry of Soft-Sediment Deformation Structure-Bearing Late Cretaceous Volcano-Sedimentary Basins in the SW Korean Peninsula and Their Tectonic Implications." Minerals 11, no. 5 (May 14, 2021): 520. http://dx.doi.org/10.3390/min11050520.
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Cretaceous volcano-sedimentary basins and successions in the Korean Peninsula are located along NE-SW- and NNE-SSW-trending sinistral strike–slip fault systems. Soft-sediment deformation structures (SSDS) of lacustrine sedimentary strata occur in the Wido, Buan, and Haenam areas of the southwestern Korean Peninsula. In this study, systematic geological, geochronological, and geochemical investigations of the volcanic-sedimentary successions were conducted to constrain the origin and timing of SSDS-bearing lacustrine strata. The SSDS-bearing strata is conformably underlain and overlain by volcanic rocks, and it contains much volcaniclastic sediment and is interbedded with tuffs. The studied SSDSs were interpreted to have formed by ground shaking during syndepositional earthquakes. U-Pb zircon ages of volcanic and volcaniclastic rocks within the studied volcano-sedimentary successions were ca. 87–84 Ma, indicating that active volcanism was concurrent with lacustrine sedimentation. Geochemical characteristics indicate that these mostly rhyolitic rocks are similar to subduction-related calc-alkaline volcanic rocks from an active continental margin. This suggests that the SSDSs in the study area were formed by earthquakes related to proximal volcanic activity due to the oblique subduction of the Paleo-Pacific Plate during the Late Cretaceous.
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Tilling, R. I. "Volcanism and associated hazards: the Andean perspective." Advances in Geosciences 22 (December 14, 2009): 125–37. http://dx.doi.org/10.5194/adgeo-22-125-2009.
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Abstract. Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3) in 1985 of Nevado del Ruiz (Colombia) killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.
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Tsatsanifos, C., V. Kontogianni, and S. Stiros. "Tunneling and other engineering works in volcanic environments: Sousaki and Thessaly." Bulletin of the Geological Society of Greece 40, no. 4 (January 1, 2007): 1733. http://dx.doi.org/10.12681/bgsg.17102.
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This study is inspired by the impacts on a tunnel of the Sousaki volcano, in the vicinity of Corinth and examines possible impacts of the Quaternary volcanism on major engineering works in Thessaly. The Sousaki volcano, at the NW edge of the Aegean Volcanic Arc has been associated with important volcanic activity in the past, but its current activity is confined to géothermie phenomena. A tunnel for the new Athens-Corinth High Speed Rail was excavated through the solfatara of the volcano, an area characterized by numerous faults and physical cavities. High temperatures and geothermal gases released in the underground opening through the faults caused disturbance to the tunnel construction, need for supplementary investigations and adoption of special measures to maintain tunnel stability. Experience from the tunnel at Sousaki indicates that similar risks may be faced in future major engineering works in other regions of Greece. Such an example is the area of Microthives and Achillio, Magnesia, Thessaly. Tunnels for the new highway and railway networks constructed or planned through at least two volcanic domes and other main engineering works may also face volcano-associated effects. Optimization of the network routes in combination with special construction techniques and safety measures need to be followed for minimization of such volcanic risks.
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Megerle, Heidi Elisabeth. "Geoheritage and Geotourism in Regions with Extinct Volcanism in Germany; Case Study Southwest Germany with UNESCO Global Geopark Swabian Alb." Geosciences 10, no. 11 (November 8, 2020): 445. http://dx.doi.org/10.3390/geosciences10110445.
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Geotourism has become more popular in recent decades. Volcanism is an essential part of geoheritage and attracts a high number of visitors. In contrast to active volcanism, Tertiary volcanism is often not identified as such by a lay audience and is understandably perceived as less spectacular. The challenge is therefore to protect the volcanic heritage, to communicate its values, and to enhance it with the help of adequate geotourism offers. Germany does not have active volcanism, but a very high quality volcanic geological heritage, especially from the Tertiary period. Fortunately, this heritage is being increasingly valued and presented in an attractive way for a lay audience. The two Geoparks in the Eifel (Rhineland-Palatinate) are pioneers in this field. The UNESCO Global Geopark Swabian Alb actually offers a well camouflaged potential. The Swabian volcano, with an area of 1600 km2, is one of the most important tuff vent areas on earth, but hardly known outside of expert groups. A comprehensive strategy for the geotouristic valorization of the Tertiary volcanic phenomena does not yet exist in the Geopark Swabian Alb.
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Schmidt, Anja, and Benjamin A. Black. "Reckoning with the Rocky Relationship Between Eruption Size and Climate Response: Toward a Volcano-Climate Index." Annual Review of Earth and Planetary Sciences 50, no. 1 (May 31, 2022): 627–61. http://dx.doi.org/10.1146/annurev-earth-080921-052816.
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Volcanic eruptions impact climate, subtly and profoundly. The size of an eruption is only loosely correlated with the severity of its climate effects, which can include changes in surface temperature, ozone levels, stratospheric dynamics, precipitation, and ocean circulation. We review the processes—in magma chambers, eruption columns, and the oceans, biosphere, and atmosphere—that mediate the climate response to an eruption. A complex relationship between eruption size, style, duration, and the subsequent severity of the climate response emerges. We advocate for a new, consistent metric, the Volcano-Climate Index, to categorize climate response to eruptions independent of eruption properties and spanning the full range of volcanic activity, from brief explosive eruptions to long-lasting flood basalts. A consistent metric for categorizing the climate response to eruptions that differ in size, style, and duration is critical for establishing the relationshipbetween the severity and the frequency of such responses aiding hazard assessments, and furthering understanding of volcanic impacts on climate on timescales of years to millions of years. ▪ We review the processes driving the rocky relationship between eruption size and climate response and propose a Volcano-Climate Index. ▪ Volcanic eruptions perturb Earth's climate on a range of timescales, with key open questions regarding how processes in the magmatic system, eruption column, and atmosphere shape the climate response to volcanism. ▪ A Volcano-Climate Index will provide information on the volcano-climate severity-frequency distribution, analogous to earthquake hazards. ▪ Understanding of the frequency of specific levels of volcanic climate effects will aid hazard assessments, planning, and mitigation of societal impacts.
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Davydova, M. Yu, Yu A. Martynov, and A. B. Perepelov. "Evolution of the isotopic-geochemical composition of rocks of Uksichan volcano, Sredinnyi range, Kamchatka, and its relations to the tectonic restyling of Kamchatka in the neogene." Петрология 27, no. 3 (May 19, 2019): 282–307. http://dx.doi.org/10.31857/s0869-5903273282-307.
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The paper presents newly acquired data on concentrations of major and trace elements and on Sr, Nd, and Pb isotope composition in Pliocene and Late Pleistocene–Holocene mafic volcanic rocks of the Uksichan volcanic center, one of the largest in the Sredinnyi Range of Kamchatka. Based on these data, the mafic Pliocene volcanics are thought to be produced by the melting of heterogenized mantle material, which had been hybridized by subduction and asthenospheric processes. The behavior of HFSE and Pb isotopic systematics provide evidence of the melting of subducted sediment and origin of pyroxenite segregations in the peridotite matrix. The low ∆8/4Pb values of the Pliocene lavas of Uksichan shield volcano and in modern large volcanic centers in the Central Kamchatka Depression are correlated with the magmatic productivity, which indicates, when considered together with HFSE and HREE behavior, that the Pacific asthenosphere was involved in the magma-generating processes. The Late Pleistocene–Holocene basalt volcanism, which was spatially constrained to the peripheries of the Pliocene shield edifice, developed in an extensional environment as a result of the melting of an enriched mantle source. The attenuation and then complete termination of volcanic activity in the Sredinnyi Range in the Late Pleistocene–Holocene was associated with an increase in the ∆8/4Pb of the mafic lavas, which indicates that the center of the activity related to the oceanic asthenosphere shifted eastward toward the Central Kamchatka Depression. The influence of the oceanic asthenosphere on subduction-related magmatism is not unique to convergence zones alone and should be taken into consideration when models are constructed for the origin of juvenile continental crust.
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Skulski, Thomas, Don Francis, and John Ludden. "Volcanism in an arc-transform transition zone: the stratigraphy of the St. Clare Creek volcanic field, Wrangell volcanic belt, Yukon, Canada." Canadian Journal of Earth Sciences 29, no. 3 (March 1, 1992): 446–61. http://dx.doi.org/10.1139/e92-039.
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The St. Clare Creek volcanic field in the southwestern Yukon overlies a tectonic transition in the Wrangell volcanic belt between subduction to the northwest in Alaska and transform faulting along the Duke River fault in the southeast. Two large polygenetic volcanic centres dominated the Miocene landscape of the St. Clare Creek field: the 18–16 Ma Wolverine centre and the 16–10 Ma Klutlan centre. The Wolverine centre evolved from a small alkaline shield volcano at 18 Ma, from which alkaline basalts, hawaiites and mugearites erupted, to a larger composite volcano between 18 and 16 Ma composed of transitional basalt, basaltic trachyandesite, trachyte and rhyolite lavas, and pyroclastic rocks. The youngest Wolverine lavas are calc-alkaline basaltic andesites, andesites, and hybrid lavas (transitional–calc-alkaline). This temporal progression from alkaline through transitional to calc-alkaline volcanism is accompanied by a systematic increase in the degree of silica saturation and decrease in Fe/Si, Nb/Y, and P/Y ratios. Klutlan lavas have lower Nb/Y and P/Y ratios and are characterized by an opposite eruption sequence. The earliest Klutlan lavas (16–13 Ma) erupted from a composite volcano and include calc-alkaline andesite, rhyolite, and hybrid trachyandesite lavas, followed by transitional basaltic trachyandesites, trachyandesites, trachytes, and rhyolites. Klutlan vulcanism between 13 and 11 Ma was dominated by basaltic fissure eruptions on the southern flanks of the earlier centre and include early mildly alkaline basalts followed by more voluminous transitional basalts. Volcanism reverted to a more central type of activity between 11 and 10 Ma and includes calc-alkaline dacite lava followed by transitional basaltic trachyandesite, trachyandesite, and trachyte lavas.The volcanic stratigraphy of the St. Clare Creek field and 40Ar/39Ar geochronological data provide the basis for understanding the origin of St. Clare magmas in a regional tectonic context. Early Wolverine alkaline volcanism largely reflects leaky transform faulting, whereas subsequent transitional and calc-alkaline lavas record the onset of subduction-related volcanism at the margins of the then active Wrangell arc. The opposite eruption sequence at the Klutlan centre records the demise of subduction-related volcanism between 16 and 13 Ma, due to northwestward migration of the subducted plate. Upwelling of asthenospheric mantle in place of the subducted slab led to the generation of transitional basalts between 13 and 11 Ma, which resulted in more evolved lavas between 11 and 10 Ma.
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Lebedeva, E. V. "Impact of volcanic and post volcanic activity on fluvial relief." Geomorphology RAS, no. 4 (November 8, 2019): 49–66. http://dx.doi.org/10.31857/s0435-42812019449-66.
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The characteristic features of the river network, the structure and functioning of the valleys affected by effusive and explosive volcanism, volcano-tectonic phenomena, gas hydrothermal activity and mud volcanism are revealed. It has been established that within flows and covers of effusives, the formation of new streams channels can occur not only due to backward erosion, but also as a result of the collapse of the roof of the near-surface lava tubes, which are actively used by underground runoff. A high erosion rate, a large volume of solid runoff, and a significant role of deflation in the transformation of the fluvial relief are characteristic for regions of domination of explosive activity. There valleys become zones of accumulation of volcanic material, which is gradually processed by mudflow, alluvial, aeolian and other processes. Volcanic-tectonic activity changes the rivers position, direction of streams and morphology of the valleys, leading to numerous reorganizations of the river network, as a result of which the valleys of modern watercourses often consist of uneven-age fragments. Valleys of hydrothermal zones are characterized by the active development of slope processes, which leads to the formation in them not only of sinter terraces, but also numerous landslide ones. Mud volcanic processes periodically lead to the filling and blocking of the valleys with mud breccia flows, which affects both the composition of the alluvium of watercourses and the morphology of the valleys.
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LEAT, P. T., R. D. LARTER, and I. L. MILLAR. "Silicic magmas of Protector Shoal, South Sandwich arc: indicators of generation of primitive continental crust in an island arc." Geological Magazine 144, no. 1 (October 27, 2006): 179–90. http://dx.doi.org/10.1017/s0016756806002925.
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Protector Shoal, the northernmost and most silicic volcano of the South Sandwich arc, erupted dacite–rhyolite pumice in 1962. We report geochemical data for a new suite of samples dredged from the volcano. Geochemically, the dredge and 1962 samples form four distinct magma groups that cannot have been related to each other, and are unlikely to have been related to a single basaltic parent, by fractional crystallization. Instead, the silicic rocks are more likely to have been generated by partial melting of basaltic lower crust within the arc. Trace element and Sr–Nd isotope data indicate that the silicic volcanics have compositions that are more similar to the volcanic arc than the oceanic basement formed at a back-arc spreading centre, and volcanic arc basalts are considered to be the likely source for the silicic magmas. The South Sandwich Islands are one of several intra-oceanic arcs (Tonga–Kermadec, Izu–Bonin) that have: (1) significant amounts of compositionally bimodal mafic–silicic volcanic products and (2) 6.0–6.5 km s−1P-wave velocity layers in their mid-crusts that have been imaged by wide-angle seismic surveys and interpreted as intermediate-silicic plutons. Geochemical and volume considerations indicate that both the silicic volcanics and plutonic layers were generated by partial melting of basaltic arc crust, representing an early stage in the fractionation of oceanic basalt to form continental crust.
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SIMKIN, T. "Monitoring Volcanism: Volcanic Hazards." Science 245, no. 4913 (July 7, 1989): 83–84. http://dx.doi.org/10.1126/science.245.4913.83.
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Head, James W., and Lionel Wilson. "Heat transfer in volcano–ice interactions on Mars: synthesis of environments and implications for processes and landforms." Annals of Glaciology 45 (2007): 1–13. http://dx.doi.org/10.3189/172756407782282570.
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AbstractWe review new advances in volcano–ice interactions on Mars and focus additional attention on (1) recent analyses of the mechanisms of penetration of the cryosphere by dikes and sills; (2) documentation of the glacial origin of huge fan-shaped deposits on the northwest margins of the Tharis Montes and evidence for abundant volcano–ice interactions during the later Amazonian period of volcanic edifice construction and (3) the circumpolar Hesperian-aged Dorsa Argentea Formation, interpreted as an ice sheet and displaying marginal features (channels, lakes and eskers) indicative of significant melting and interior features interpreted to be due to volcano–ice interactions (e.g. subglacial volcanic edifices, pits, basins, channels and eskers). In this context, we describe and analyse several stages and types of volcano–ice interactions: (1) magmatic interactions with ice-rich parts of the cryosphere; (2) subglacial volcanism represented by intrusion under and into the ice and formation of dikes and moberg-like ridges, intrusion of sills at the glacier–volcano substrate interface and their evolution into subglacial lava flows, formation of subglacial edifices, marginal melting and channels; (3) synglacial (ice contact) volcanism represented by flows banking up against glacier margins, chilling and forming remnant ridges and (4) post-glacial volcanism and interactions with ice deposits.
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Kereszturi, Gábor, and Károly Németh. "Shallow-seated controls on the evolution of the Upper Pliocene Kopasz-hegy nested monogenetic volcanic chain in the Western Pannonian Basin (Hungary)." Geologica Carpathica 62, no. 6 (December 1, 2011): 535–46. http://dx.doi.org/10.2478/v10096-011-0038-3.
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Shallow-seated controls on the evolution of the Upper Pliocene Kopasz-hegy nested monogenetic volcanic chain in the Western Pannonian Basin (Hungary)Monogenetic, nested volcanic complexes (e.g. Tihany) are common landforms in the Bakony-Balaton Highland Volcanic Field (BBHVF, Hungary), which was active during the Late Miocene up to the Early Pleistocene. These types of monogenetic volcanoes are usually evolved in a slightly different way than their "simple" counterparts. The Kopasz-hegy Volcanic Complex (KVC) is inferred to be a vent complex, which evolved in a relatively complex way as compared to a classical "sensu stricto" monogenetic volcano. The KVC is located in the central part of the BBHVF and is one of the youngest (2.8-2.5 Ma) volcanic erosion remnants of the field. In this study, we carried out volcanic facies analysis of the eruptive products of the KVC in order to determine the possible role of changing magma fragmentation styles and/or vent migration responsible for the formation of this volcano. The evolution of the KVC started with interaction of water-saturated Late Miocene (Pannonian) mud, sand, sandstone with rising basaltic magma triggering phreatomagmatic explosive maar-diatreme forming eruptions. These explosive eruptions in the northern part of the volcanic complex took place in a N-S aligned paleovalley. As groundwater supply was depleted during volcanic activity the eruption style became dominated by more magmatic explosive-fragmentation leading to the formation of a mostly spatter-dominated scoria cone that is capping the basal maar-diatreme deposits. Subsequent vent migration along a few hundred meters long fissure still within the paleovalley caused the opening of the younger phreatomagmatic southern vent adjacent to the already established northern maar. This paper describes how change in eruption styles together with lateral migration of the volcanism forms an amalgamated vent complex.
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Preine, J., J. Karstens, C. Hübscher, P. Nomikou, F. Schmid, G. J. Crutchley, T. H. Druitt, and D. Papanikolaou. "Spatio-temporal evolution of the Christiana-Santorini-Kolumbo volcanic field, Aegean Sea." Geology 50, no. 1 (January 1, 2022): 96–100. http://dx.doi.org/10.1130/g49167.1.
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Abstract The Christiana-Santorini-Kolumbo volcanic field (CSKVF) in the Aegean Sea is one of the most active volcano-tectonic lineaments in Europe. Santorini has been an iconic site in volcanology and archaeology since the 19th century, and the onshore volcanic products of Santorini are one of the best-studied volcanic sequences worldwide. However, little is known about the chronology of volcanic activity of the adjacent submarine Kolumbo volcano, and even less is known about the Christiana volcanic island. In this study, we exploit a dense array of high-resolution marine seismic reflection profiles to link the marine stratigraphy to onshore volcanic sequences and present the first consistent chronological framework for the CSKVF, enabling a detailed reconstruction of the evolution of the volcanic rift system in time and space. We identify four main phases of volcanic activity, which initiated in the Pliocene with the formation of the Christiana volcano (phase 1). The formation of the current southwest-northeast–trending rift system (phase 2) was associated with the evolution of two distinct volcanic centers, the newly discovered Poseidon center and the early Kolumbo volcano. Phase 3 saw a period of widespread volcanic activity throughout the entire rift. The ongoing phase 4 is confined to the Santorini caldera and Kolumbo volcano. Our study highlights the fundamental tectonic control on magma emplacement and shows that the CSKVF evolved from a volcanic field with local centers that matured only recently to form the vast Santorini edifice.
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Garcia, Sebastian, and Gabriela Badi. "Towards the development of the first permanent volcano observatory in Argentina." Volcanica 4, S1 (November 1, 2021): 21–48. http://dx.doi.org/10.30909/vol.04.s1.2148.
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Argentina is a country that presents a complex situation regarding volcanic risk, where a total of 38 volcanoes are considered active. Although Argentina has no major cities close to these volcanoes, the continuous increase in economic activity and infrastructure near the Andean Codillera will increase exposure to volcano hazards in the future. Further, volcanic activity on the border between Argentina and Chile poses a unique challenge in relation to volcano monitoring and the management of volcanic emergencies. Additionally, due to atmospheric circulation patterns in the region (from West to East), Argentina is exposed to ashfall and ash dispersion from frequent explosive eruptions from Chilean volcanoes. Considering this, the Servicio Geológico Minero Argentino (SEGEMAR) decided to create and implement a Volcanic Threat Assessment Program, which includes the creation of the the first permanent volcano observatory for the country, the Observatorio Argentino de Vigilancia Volcánica (OAVV). Previously the Decepcion Island volcano observatory was created as a collaboration between the Instituto Antártico Argentino (IAA) and the Museo Nacional de Ciencias Naturales (MNCN) from the Consejo Superior de Investigaciones Científicas (CSIC). Argentina es un país que presenta una compleja situación con respecto al riesgo volcánico, donde un total de 38 volcanes son considerados activos. Aunque Argentina no tiene ciudades importantes cerca de estos volcanes, el continuo incremento de la actividad económica y la infraestructura cerca de la Cordillera de los Andes, generará en el futuro un aumento en la exposición a estos peligros. Además, la actividad volcánica en la frontera entre Argentina y Chile constituye un desafío único en relación con el monitoreo de volcanes y la gestión de emergencias volcánicas. Adicionalmente, debido a los patrones de circulación atmosférica en la región (desde el oeste hacia el este), Argentina está expuesta a la caída y dispersión de cenizas de las frecuentes erupciones explosivas de volcanes chilenos. Teniendo esto en cuenta, el Servicio Geológico Minero Argentino (SEGEMAR) decidió crear e implementar un programa de evaluación de amenazas volcánicas, que incluye, la creación del primer observatorio permanente de volcanes para el país, el Observatorio Argentino de Vigilancia Volcánica (OAVV). Previamente, el Observatorio Volcanológico de la Isla Decepción fue creado como una colaboración entre el Instituto Antártico Argentino (IAA) y el Museo Nacional de Ciencias Naturales (MNCN) del Consejo Superior de Investigaciones Científicas de España (CSIC).
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Annisa, Y., G. C. Astriyan, S. Wahyunia, N. Indrastuti, and M. F. I. Massinai. "Determination of Hypocenter Using Geiger Method in Sinabung Volcano, April-July 2016 Period." IOP Conference Series: Earth and Environmental Science 873, no. 1 (October 1, 2021): 012007. http://dx.doi.org/10.1088/1755-1315/873/1/012007.
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Abstract Sinabung is a volcano located in the Karo Highlands, Karo District, North Sumatra, Indonesia, with the highest peak of 2460 meters mean sea level. Volcanic earthquake is an earthquake that occurs due to volcanic activity. This is caused by the movement of magma upwards in the volcano. This study aims to determine the type of earthquake, hypocenter position and epicenter of volcanic earthquakes in Sinabung volcano in April-July 2016. The principle of this study was carried out by analyzing volcanic earthquake data in Sinabung volcano in April-July 2016. The data is recorded data (seismogram) or in other words is secondary data from Sinabung volcano on 7 seismometer stations namely Sukanalu, Lau Kawar, Sigarang-Garang, Mardinding, Gamber, Sibayak, and Kebayaken stations. Earthquake data in April-July 2016 revealed that there were 24 earthquake events in a period of 3 months which were the results of picking up the P and S waves, where volcanic earthquakes were obtained only in the form of volcanic earthquake type A and type B volcanic earthquake. Sinabung volcano has an earthquake activity that high enough so that the status of Sinabung volcano is still at level III (standby) status. Based on the hypocenter of several VA and VB earthquakes that occurred in April-July 2016, it can be concluded that the distribution of the hypocenter of the volcanic earthquake shows that the maximum depth of the volcanic earthquake is 10.000 meters and the position of the earthquake is spread at the point between Sinabung volcano and Mount Sibayak.
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Li, Hong Juan, Wei Lin Yan, Gui Wen Wang, Jian Wei Fu, Chun Yan Wang, Hua Peng Niu, Hao Qin, and Dan Cang. "Well Logging Identification Methods for Volcanic Lithofacies in the North of Songliao Basin, China." Advanced Materials Research 734-737 (August 2013): 224–34. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.224.
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Volcanic lithology and lithofacies are important factors to control the formation of volcanic reservoir. It is a challenge for geologists and petrophysicist to identify lithofacies in the borehole by using well logs. According to the reservoir characters of Daqing volcanic reservoir in Songliao basin, five lithofacies and fifteen su-facies have been recognized through the drilled core analysis of lithology, texture and structure. The relationship between conventional well logs and volcanic lithology can be established by calibrating with core analysis which can be used to identify the rock composition by the established cross-plots. From the FMI measurement, the differences of resistivity values caused by volcanic rock texture and structure can be showed in the image clearly. It shows that four kinds of textures and five kinds of structure can be identified with FMI image. As the volcanic lithofacies marks, specific volcanics lithology, texture and structure corresponds to the specific lithofacies and sub-facies. So lithofacies distribution can be evaluated effectively with the model of volcanics texture and structure combined with rock composition. The results of study indicate that the composition, texture and structure characteristics of the volcanics can be identified by conventional log with FMI measurement, which is important to the further volcanic reservoir exploration and production.
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Mather, Ben R., R. Dietmar Müller, Maria Seton, Saskia Ruttor, Oliver Nebel, and Nick Mortimer. "Intraplate volcanism triggered by bursts in slab flux." Science Advances 6, no. 51 (December 2020): eabd0953. http://dx.doi.org/10.1126/sciadv.abd0953.
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Long-lived, widespread intraplate volcanism without age progression is one of the most controversial features of plate tectonics. Previously proposed edge-driven convection, asthenospheric shear, and lithospheric detachment fail to explain the ~5000-km-wide intraplate volcanic province from eastern Australia to Zealandia. We model the subducted slab volume over 100 million years and find that slab flux drives volcanic eruption frequency, indicating stimulation of an enriched mantle transition zone reservoir. Volcanic isotope geochemistry allows us to distinguish a high-μ (HIMU) reservoir [>1 billion years (Ga) old] in the slab-poor south, from a northern EM1/EM2 reservoir, reflecting a more recent voluminous influx of oceanic lithosphere into the mantle transition zone. We provide a unified theory linking plate boundary and slab volume reconstructions to upper mantle reservoirs and intraplate volcano geochemistry.
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DeWolfe, Y. M., H. L. Gibson, B. Lafrance, and A. H. Bailes. "Volcanic reconstruction of Paleoproterozoic arc volcanoes: the Hidden and Louis formations, Flin Flon, Manitoba, CanadaThis is a companion paper to DeWolfe, Y.M., Gibson, H.L., and Piercey, S.J. 2009. Petrogenesis of the 1.9 Ga mafic hanging wall sequence to the Flin Flon, Callinan, and Triple 7 massive sulphide deposits, Flin Flon, Manitoba, Canada. Canadian Journal of Earth Sciences, 46: this issue." Canadian Journal of Earth Sciences 46, no. 7 (July 2009): 481–508. http://dx.doi.org/10.1139/e09-031.
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The hanging wall to the Flin Flon, Callinan, and Triple 7 volcanogenic massive sulphide deposits of the Flin Flon district is composed of the Hidden and Louis formations. The contact between these formations is marked by mafic tuff that represents a hiatus in effusive volcanism. The formations form a composite volcanic edifice that was erupted and grew within a large, volcanic–tectonic subsidence structure (hosting the deposits) that developed within a rifted-arc environment. The formations are evidence of resurgent effusive volcanism and subsidence following a hiatus in volcanism marked by ore formation since they consist of dominantly basaltic flows, sills, and volcaniclastic rocks with subordinate basaltic andesite and rhyodacitic flows and volcaniclastic rocks. The Hidden formation is interpreted to represent a small shield volcano and the Louis formation a separate shield volcano that developed on its flank. Both the Hidden and Louis volcanic edifices were constructed by continuous, low-volume eruptions of pillow lava. A gradual change from a dominantly extensional environment during the formation of the footwall Flin Flon formation to a progressively more dominant convergent environment during the emplacement of the hanging wall suggests that the Hidden and Louis formations are unlikely to host significant volcanogenic massive sulphide-type mineralization. However, synvolcanic structures in the formations define structural corridors that project downwards into the footwall where they encompass massive sulphide mineralization, indicating their control on ore formation, longevity,and reactivation as magma and fluid pathways during the growth of the Hidden and Louis volcanoes.
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Pécskay, Zoltán, Alexandra Harkovska, and Alexander Hadjiev. "K-Ar dating of Mesta volcanics (SW Bulgaria)." Geologica Balcanica 30, no. 1-2 (June 30, 2000): 3–11. http://dx.doi.org/10.52321/geolbalc.30.1-2.3.
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The Mesta volcanic massif (SW Bulgaria) belongs to the Macedonian-Rhodope-North Aegean Magmatic Zone. It crops out along the middle course of Mesta River and covers about 200 km2 of the homonymous graben. The bаsеmеnt of Mesta graben and the neighbouring elevated blocks of Pirin and Western Rhodope mountains are composed of high-grade metamorphics, hosting granitoidic plutons of diverse ages, including the Paleogene Central Pirin and Teshevo plutons. Apart from the volcanic bodies, the graben-fill consists of complexly interfingered Paleogene stratified continental terrigenous sedimentary rocks, volcanogenic-sedimentary rocks and volcaniclastics (both руrо-, and epiclastics), overlain unconformably bу Neogene and Quaternary deposits. The Mesta volcanics are represented by two main types: high-K calc-alkaline to shoshonitic dacites (in some places with а transition to latites) and high-K calc-alkaline rhyodacites. The magmatic bodies of subvolcanic and extrusive facies are represented by а number of morphologic varieties, which belongs to two polygonal caldera structures (Кrеmеn and Banichan) and two linear magmato-tectonic zones (Gostoun and Dobrinishte). This paper presents 12 К-Аг ages obtained for 11 lауа bodies of different geological position and for one re-deposited volcanic clast from the middle part of the stratified Paleogene section. The ages are in support of the suggestion that the Mesta volcanics originated from а zoned magma chamber. More silicic (rhyodacitic) eruptions and subvolcanic intrusions are related to earlier volcanic events in the northern part of the massif - оn the territories of the Кrеmеn caldera, Gostoun and Dobrinishte zones. These events (approximately 33-31 Ма) are рге-, and sincollapse ones in respect to the Кrеmеn caldera formation. The later (sin- and post-collapse) rhyodacitic eruptions were accompanied and followed by eruptions and subvolcanic intrusions of less silicic, dacitic melts (31-28 Ма). The main portion of the dacites is related to the centres in the Banichan caldera (29-28 Ма). The time-span obtained covers the events of the paroxysmal volcanic activity in the Mesta graben only. Thus it is shorter than the real time-interval of the volcanism. This time-span is comparable with that of the voluminous Раlеоgene volcanism in the Smolyan region (Central Rhodopes). The Rb-Sr ages of neighbouring Teshevo and Central Pirin plutons plot in its boundaries as well. Some recommendations for more detailed and precise future radiometric studies are proposed to define the age of the initial and the final volcanic events in the Paleogene Mesta graben.
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Iguchi, Masato. "Method for Real-Time Evaluation of Discharge Rate of Volcanic Ash – Case Study on Intermittent Eruptions at the Sakurajima Volcano, Japan –." Journal of Disaster Research 11, no. 1 (February 1, 2016): 4–14. http://dx.doi.org/10.20965/jdr.2016.p0004.
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A method for evaluating the volcanic ash discharge rate by using seismic and ground deformation signals is proposed to obtain this rate in real time for southern Kyushu’s Sakurajima volcano. This volcano repeats vulcanian eruptions accompanying significant ground deformation showing deflation and nonvulcanian type eruptions that emit the minor emissions of volcanic ash associated with volcanic tremors but without significant ground deformation. We examined ground deformation and seismic amplitude as they relate to monthly sums of volcanic ash weight ejected from craters. We found that in monthly sums, both deflation ground deformation and the amplitude of volcanic tremors correlate positively with the weight of ejected volcanic ash. A linear combination of terms for ground deformation, seismic amplitude and a correction factor correlates better than single parameter of deflation or seismic amplitude with volcanic ash weight. The linear combination provides the volcanic ash discharge rate in quasi-real time and the total amount of volcanic ash distributed over a wide area immediately after a volcanic eruption ends.
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Van Eaton, Alexa R., Cassandra M. Smith, Michael Pavolonis, and Ryan Said. "Eruption dynamics leading to a volcanic thunderstorm—The January 2020 eruption of Taal volcano, Philippines." Geology 50, no. 4 (January 18, 2022): 491–95. http://dx.doi.org/10.1130/g49490.1.
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Abstract Advances in global lightning detection have provided novel ways to characterize explosive volcanism. However, researchers are still at the early stages of understanding how volcanic plumes become electrified on different spatial and temporal scales. We deconstructed the phreatomagmatic eruption of Taal volcano (Philippines) on 12 January 2020 to investigate the origin of its powerful volcanic thunderstorm. Satellite analysis indicated that the water-rich plume rose >10 km high before creating lightning detected by Vaisala's global lightning data set (GLD360). Flash rates increased with plume heights and cloud expansion over time, producing >70 flashes min–1. Photographs revealed a highly electrified region at the base of the umbrella cloud, where we infer strong convective updrafts and icy collisions enhanced the electrical activity. These findings inform a conceptual model with overlapping regimes of charge generation in wet eruptions—initially due to ash particle collisions near the vent, followed by thunderstorm-like electrification in icy regions of the upper plume. Despite the wide reach of Taal's ash cloud, most of the lightning occurred within 20–30 km of the volcano, producing thousands of hazardous cloud-to-ground flashes over a densely populated area. The eruption demonstrates that volcanic lightning can pose a hazard in its own right, embedded within the broader hazards of explosive volcanism in an urban setting.
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Barberi, F., M. Coltelli, G. Ferrara, F. Innocenti, J. M. Navarro, and R. Santacroce. "Plio-Quaternary volcanism in Ecuador." Geological Magazine 125, no. 1 (January 1988): 1–14. http://dx.doi.org/10.1017/s0016756800009328.
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AbstractExtensive sampling, major element chemistry on over 300 samples and K-Ar radiometric dating have been carried out on the Ecuadorian Upper Tertiary–Quaternary volcanoes. The results show important space–time variations of the volcanic activity, between Late Miocene time and the present. In Late Miocene time a continuous volcanic belt, located approximately along the present volcanic front (VF), affected the whole country from the Cuenca basin to the south, up to Colombia to the north. Major changes occurred at about 5 Ma: volcanic activity stopped south of the Guayaquil fault belt and never resumed; to the north the active volcanic axis shifted eastward to the Cordillera Real (CR) area with a simultaneous relative decrease in intensity. Since Early Quaternary time the volcanic belt widened westward to the Western Cordillera where the volcanism resumed at about 1.5–1.0 Ma, giving rise to the very wide active volcanic zone of Ecuador.The Plio-Quaternary products show significant longitudinal and latitudinal chemical and mineralogical changes. Volcanics of the VF and Interandean Depression contain amphibole and define a calc-alkaline trend with a K2O content lower than that of the CR products, which are characterized by a mostly anhydrous phenocryst assemblage. In both areas andesites dominate, but extreme compositions (basaltic andesites and rhyolites) are more diffuse in the CR than the VF. No significant transverse zoning has been detected in the northern region (north of the Chota-Mira transverse tectonic line). The observed temporal and spatial variations are interpreted as a result of the subduction of the Carnegie Ridge anomalous oceanic crust, underthrusting of which began approximately 6 Ma ago.
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Monjoie, Philippe, Henriette Lapierre, Artan Tashko, Georges H. Mascle, Aline Dechamp, Bardhyl Muceku, and Pierre Brunet. "Nature and origin of the Triassic volcanism in Albania and Othrys: a key to understanding the Neotethys opening?" Bulletin de la Société Géologique de France 179, no. 4 (July 1, 2008): 411–25. http://dx.doi.org/10.2113/gssgfbull.179.4.411.
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AbstractTriassic volcanic rocks, stratigraphically associated with pelagic or reef limestones, are tectonically juxtaposed with Mesozoic ophiolites in the Tethyan realm. From the central (Dinarides, Hellenides) and eastern Mediterranean (Antalya, Troodos, Baër Bassit) to the Semail nappes (Oman), they occur either associated to the tectonic sole of the ophiolitic nappes or as a distinct tectonic pile intercalated between the ophiolites and other underthrust units. In the Dinaro-Hellenic belt, the Pelagonian units represent the lower plate, which is underthrust beneath the ophiolites. Middle to Late Triassic volcanic sequences are interpreted as the eastern flank of the Pelagonian platform and are therefore considered as a distal, deep-water part of the Pelagonian margin.The Triassic volcanics from Albania and Othrys are made up of basaltic pillowed and massive flows, associated locally with dolerites and trachytes. New elemental, Nd and Pb isotopic data allow to recognize four types of volcanic suites: (1) intra-oceanic alkaline and tholeiitic basalts, (2) intra-oceanic arc-tholeiites, (3) back-arc basin basalts, (4) calc-alkaline mafic to felsic rocks. Nd and Pb isotopic initial ratios suggest that the within-plate volcanic rocks were derived from an enriched oceanic island basalt type mantle source, devoid of any continental crustal component. The lower εNd value of the trachyte could be due to assimilation of oceanic altered crust or sediments in a shallow magma chamber. Island arc tholeiites and back-arc basin basalts have a similar wide range of εNd. The absence of Nb negative anomalies in the back-arc basin basalts suggests that the basin floored by these basalts was wide and mature. The high Th contents of the island arc tholeiites suggest that the arc volcanoes were located not far away from the continental margin.Albania and Othrys volcanics contrast with the Late Triassic volcanism from eastern Mediterranean (SW Cyprus, SW Turkey), which displays solely features of oceanic within plate suites. The presence of back-arc basin basalts associated with arc-related volcanics in Central Mediterranean indicates that they were close to a still active subduction during the Upper Triassic, while back-arc basins developed, associated with within-plate volcanism, leading to the NeoTethys opening.
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Melling, David R., Charles E. Blackburn, David H. Watkinson, and Jack R. Parker. "Geological setting of gold, western Wabigoon Subprovince, Canadian Shield: exploration targets in mixed volcanic successions." Canadian Journal of Earth Sciences 25, no. 12 (December 1, 1988): 2075–88. http://dx.doi.org/10.1139/e88-192.
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The Archean volcanic rocks in the Cameron–Rowan lakes area may be divided into three distinct successions based on field mapping, petrographic studies, and lithogeochemical characteristics. The lowermost Rowan Lake Volcanics are tholeiitic pillowed basalts. These rocks are unconformably overlain by the Cameron Lake Volcanics, a mixed succession of tholeiitic massive and pillowed basalts and intermediate to felsic volcaniclastic rocks. The Brooks Lake Volcanics consist of tholeiitic basalts and represent the youngest volcanic rocks at the top of the preserved succession.Most of the gold concentrations in the Cameron–Rowan lakes area are confined to the mixed Cameron Lake Volcanics. The majority of these, including the Cameron Lake deposit, occur within shear zones near lithologic contacts. In the Eagle–Wabigoon and Manitou lakes areas there are similar stratigraphic subdivisions of the supracrustal rocks and many of the gold concentrations also occur in deformation zones within the mixed volcanic successions. The contrasting competencies among the basalts, the intermediate to felsic volcaniclastic rocks, and the intrusive rocks, which are characteristic of the mixed volcanic successions, localized stress during deformation, forming shear zones into which gold-bearing fluids gained access. The potential for successfully delineating economic gold concentrations appears greatest in the mixed volcanic successions within these areas and elsewhere in the western Wabigoon Subprovince of the Canadian Shield.
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TAKASHIMA, REISHI, HIROSHI NISHI, and TAKEYOSHI YOSHIDA. "Late Jurassic–Early Cretaceous intra-arc sedimentation and volcanism linked to plate motion change in northern Japan." Geological Magazine 143, no. 6 (September 4, 2006): 753–70. http://dx.doi.org/10.1017/s001675680600255x.
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The Sorachi Group, composed of Upper Jurassic ophiolite and Lower Cretaceous island-arc volcano-sedimentary cover, provides a record of Late Jurassic–Early Cretaceous sedimentation and volcanism in an island-arc setting off the eastern margin of the Asian continent. Stratigraphic changes in the nature and volume of the Sorachi Group volcanic and volcaniclastic rocks reveal four tectonic stages. These stages resulted from changes in the subduction direction of the Pacific oceanic plate. Stage I in the Late Jurassic was characterized by extensive submarine eruptions of tholeiitic basalt from the back-arc basin. Slab roll-back caused rifting and sea-floor spreading in the supra-subduction zone along the active Asian continental margin. Stage II corresponded to the Berriasian and featured localized trachyandesitic volcanism that formed volcanic islands with typical island-arc chemical compositions. At the beginning of this stage, movement of the Pacific oceanic plate shifted from northeastward to northwestward. During Stage III, in the Valanginian, submarine basaltic volcanism was followed by subsidence. The Pacific oceanic plate motion turned clockwise, and the plate boundary between the Asian continent and the Pacific oceanic plate changed from convergent to transform. During Stage IV in the Hauterivian–Barremian, in situ volcanism ceased in the Sorachi–Yezo basin, and the volcanic front migrated west of the Sorachi–Yezo basin.
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CITRONI, SERGIO B., MIGUEL A. S. BASEI, OSWALDO SIGA JR., and JOSÉ M. DOS REIS NETO. "Volcanism and stratigraphy of the Neoproterozoic Campo Alegre Basin, SC, Brazil." Anais da Academia Brasileira de Ciências 73, no. 4 (December 2001): 581–97. http://dx.doi.org/10.1590/s0001-37652001000400012.
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The depositional succession of the Campo Alegre Basin (Santa Catarina - southern Brazil) was investigated having the evolution of the volcanic activity as background. The different stratigraphic units are interpreted as belonging to different volcanic stages: Bateias Formation, conglomerates and sandstones, related with a pre-volcanic stage; Campo Alegre Group, at the main volcanic stage, with each different formation corresponding to different episodes of volcanism - Rio Negrinho Formation, corresponding to the basic volcanism, Avenca Grande Formation to ignimbritic event, Serra de São Miguel Formation to the acid volcanism and Fazenda Uirapuru Formation, related to an explosive event; Rio Turvo and Arroio Água Fria formations correspond respectively to inner and extra-caldera deposits.
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Hu, Yiwei, Boxi Li, and Yue Yin. "The Causes of Volcanic Eruptions and How They Affect Our Environment." Highlights in Science, Engineering and Technology 26 (December 30, 2022): 391–96. http://dx.doi.org/10.54097/hset.v26i.4013.
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Volcanic eruptions often have an impact on the environment. In the context of the environmental problem of global warming, a large amount of carbon dioxide released by volcanic eruptions will aggravate the greenhouse effect, which has aroused widespread concern. This article first explains the volcano's cone-shaped structure with several craters, cones, and vents. Although each volcano is unique, most volcanoes can be separated into three major types, the first type is a cinder cone, the second type is a composite volcano, and the third type is a shield volcano. Furthermore, this article interprets the causes of volcanic eruptions by decompression melting, and crustal movement. In addition to this, the environmental impacts of volcanic eruptions from three different angles are explained in the article. The First is the environmental impact of volcanic eruptions at different latitudes. It not only examines the sea surface temperatures' responses to volcanic forcing but also mentions a phenomenon of wind (El Niño de Navidad) caused by volcanic. The second argument is the impact of volcanic eruption on climate. It explains the effects of volcanic dust, Sulphur dioxide, and greenhouse gases, these three main volcanic substances that contribute to environmental cooling, acid rain, and global warming respectively. The final point is the impact of volcanic eruption on the benefits and disadvantages of plant cultivation, hoping this article could raise awareness of volcanoes and global environmental problems and prevent them.
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Zhao, Bo, Debing Xu, Zhida Bai, and Zhengquan Chen. "Hydro-Volcanism in the Longgang Volcanic Field, Northeast China: Insights from Topography, Stratigraphy, Granulometry and Microtexture of Xidadianzi Maar Volcano." Minerals 12, no. 9 (August 31, 2022): 1113. http://dx.doi.org/10.3390/min12091113.
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Hydro-volcanism in the Longgang volcanic field (LVF) of Northeast China has produced a dozen maars with features of complex sequences. To better understand the formation mechanism of maar volcanos in the LVF, this study focuses on the Xidadianzi (XDDZ) maar volcano, located in the Jinchuan valley of the LVF. Based on detailed stratigraphy analysis, 14C geochronology, grain-size distribution, and scanning electron microscopy (SEM) analysis, the eruptive sequence of the XDDZ volcano, including the South Crater and the North Crater, was constructed. The whole sequence was formed after four eruptive phases, including a wet phreatomagmatic eruption, an explosive magmatic eruption, a dry and hot phreatomagmatic eruption, and a small explosive magmatic eruption. 14C geochronology indicates that the formation age of XDDZ is 15,900 ± 70 years, BP. Topographic and stratigraphic characteristics show that the landforms of two craters were damaged and buried because of the destruction of lava flows and agricultural modification. The NE- trending fissure in the hard rock area is thought to participate in the formation of the XDDZ maar volcano.
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Panigrahi, Biswajit. "Lithofacies and petrochemical characterization of volcano-sedimentary sequence of Chandil Formation around Kharidih-Bareda area, Seraikela-Kharsawan District, Jharkhand: implications for uranium mineralization." Journal of The Indian Association of Sedimentologists 38, no. 2 (December 31, 2021): 37–48. http://dx.doi.org/10.51710/jias.v38i2.133.
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Mesoproterozoic Chandil Formation (ca. 1600 Ma) of North Singhbhum Mobile Belt record numerous features of felsic volcaniclastics and felsic to intermediate volcanics preserved in the central sector of the fold belt around Kharidih-Bareda area, Seraikela-Kharsawan district, Jharkhand. The felsic volcanic rocks exhibit flow bands, autoclasts and layering of crystal mushes revealing viscous nature of eruptives. The volcaniclastic sediments comprise of significant proportion of volcanic epiclasts and accidental lithic fragments. These volcaniclastics have been categorized into five prominent lithofacies viz, stratified lapilli tuff, banded tuff, tuff with penecontemporaneous deformation, welded lapilli stones, vitric tuff and volcanic bombs by field and petrographic studies of outcrops and subsurface borehole cores. The welded lapilli tuffs display fiamme and eutaxitic texture. Interlayering of the volcaniclastics, which are most often pyrite-rich, with psamo-pelitic lithology like carbonaceous phyllite, variegated phyllite, quartzite and minor limestone is suggestive of marine euxenic depositional environment. Petrographic study of the volcaniclastics indicated presence of glass shards, garnet phenocrysts, spherules of tremolite, ovoid to lenticular accretionary lapilli along with devitrified glassy material. Compositionally these felsic volcanics and volcaniclastics are rhyodacitic to andesitic in nature with peraluminous to meta aluminous in character. A/CNK values vary from 0.52 to 2.42 in felsic volcanics and from 0.12 to 1.63 in volcaniclastics. Signatures of arc magmatism is indicated by low concentration of HFS elements such as Nb (5-17 ppm), Ga (11-17 ppm) and Y (5-28 ppm). Elevated intrinsic content of uranium (3-8 ppm), Th/U ratio ranging from 1.2 to 13.2, presence of metamict allanite and zircon in volcanics and volcaniclastics reveal their suitability as a prospective source for search of uranium mineralization. The volcanic-volcaniclastic-clastic association of the Chandil Formation provides an ideal situation where provenance and province both are available. Thus, suitable litho-structural locales such as the concealed shear zones sympathetic to the Dalma thrust and South Purulia Shear Zone within the volcano-sedimentary package of Chandil Formation may be targeted as preferable sites for locating concealed uranium mineralization.
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Castro Carcamo, Rodolfo Antonio, and Eduardo Gutiérrez. "Volcanic monitoring and hazard assessment in El Salvador." Volcanica 4, S1 (November 1, 2021): 183–201. http://dx.doi.org/10.30909/vol.04.s1.183201.
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The Salvadorean volcanic range forms part of Central America Volcanic Arc and is located on the Pacific ring of fire. El Salvador is a country with at least twenty Holocene-active volcanic structures and where most of the population, including the metropolitan area of San Salvador, live near a volcanic complex. Currently, there are six active volcanoes that are continuously monitored by the Observatorio de Amenazas y Recursos Naturales, which is part of the Ministerio del Medio Ambiente y Recursos Naturales. Volcano monitoring involves seismic, geochemical, and visual monitoring techniques, among others. In addition to volcano monitoring and with the aim of early warning of future eruptions, volcanic hazard maps and networks of local observers have been developed. These initiatives together with the general directorate of civil protection, seek to meet the goal of reducing risk from volcanic activity in El Salvador. La cadena volcánica salvadoreña forma parte del Arco Volcánico de América Central y está localizada dentro de la zona conocida como cinturón de fuego del Pacífico. El Salvador es un país donde se encuentran al menos 20 estructuras volcánicas que han estado activas durante el Holoceno y donde la mayor parte de la población, incluyendo la ciudad capital San Salvador, está ubicada en las proximidades de algún complejo volcánico. Actualmente, seis volcanes activos son continuamente monitoreados por el Observatorio de Amenazas y Recursos Naturales, que es parte del Ministerio del Medio Ambiente y Recursos Naturales. El monitoreo volcánico se realiza mediante técnicas de monitoreo sísmicas, geoquímicas, visuales, entre otras. Como complemento del trabajo de monitoreo, se han desarrollado mapas de amenaza volcánica y redes de observadores locales constituyendo así sistemas de alerta temprana ante futuras erupciones. Estas iniciativas, en conjunto con la dirección general de la protección civil, persiguen el objetivo de reducir el riesgo por actividad volcánica en El Salvador.
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Ardian, D. N., H. Darmawan, Wahyudi, B. W. Mutaqin, Suratman, N. Haerani, and Wikanti. "Grain size, mineralogical, and geochemistry of the 1996-2018 Volcanic Products of Anak Krakatau Volcano, Indonesia." IOP Conference Series: Earth and Environmental Science 1071, no. 1 (August 1, 2022): 012017. http://dx.doi.org/10.1088/1755-1315/1071/1/012017.
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Abstract Anak Krakatau Volcano is the only active volcano on Krakatau Volcanic Complex. It is located in the Sunda Strait as part of the Quaternary volcanic arc as a result of the Indo-Australian plate subduction under the Eurasian plate. The volcanic activity of the Anak Krakatau volcano since 1927 is considered to be very active with a combination of explosive and effusive eruptions. Lava flow tends to be concentrated in the southwestern part, except for the 1996 lava flow (north) and 1993 lava flow (northeast). In 2018 there was an eruption accompanied by flank collapse on the southwestern side, caused by the accumulation of the instability volcanic body due to volcanic and tectonic activity. The volcanic activity will be reflected in the resulting deposits. This study was conducted to determine the characteristics of the deposits, especially on the northern part for post-1996. The analysis carried out included the stratigraphic columns, granulometric, petrography, and geochemistry analysis.
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Flèche, M. R., and G. Camiré. "Geochemistry and provenance of metasedimentary rocks from the Archean Golden Pond sequence (Casa Berardi mining district, Abitibi subprovince)." Canadian Journal of Earth Sciences 33, no. 5 (May 1, 1996): 676–90. http://dx.doi.org/10.1139/e96-051.
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The Archean Golden Pond sequence is made up of deformed and metamorphosed conglomerates, greywackes, and mafic volcanic rocks, and is overlain by ferrugineous metasedimentary rocks of the North iron formation. The clastic rocks were derived mainly from a volcanic source that had undergone weak chemical weathering. Their source area was dominated by the presence of 60–80% high-Al2O3 felsic volcanics having strongly fractionated [La/Sm]N (= 3.7 ± 0.3) and very low Ta/Th ratios (= 0.09 ± 0.02), with lesser proportions of basaltic (10–30%) and ultramafic volcanic rocks (1–10%). The ferrugineous metasedimentary rocks can be modelled by mixing 20–40% siliciclastic material, of the composition of the average Golden Pond greywacke, with an Fe- and Si-rich precipitate (molecular Fe/Si = 0.6 ± 0.2). The high-Al2O3 felsic source rocks were most likely produced by subduction processes within an oceanic arc environment, but the mafic and ultramafic volcanic rocks were derived by different processes from an asthenospheric mantle source, possibly in an oceanic rift environment. Therefore, it is suggested that the ultramafic, mafic, and felsic volcanic rocks were brought to the same erosional level by dissection of the arc system and rapid exhumation of the felsic arc lithologies and the deeper ocean floor. Intrabasinal hydrothermal activity associated with contemporaneous mafic volcanism and (or) graben development may have also been responsible for the local production of the Fe-rich precipitates of the North iron formation.
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Degeai, Jean-Philippe, and Jean-François Pastre. "Évolution morphostructurale du plateau volcano-sédimentaire de Gergovie au Miocène inférieur : implications géodynamiques sur la phase tardi-tectonique du rift de Limagne (Massif central, France)." Canadian Journal of Earth Sciences 45, no. 6 (June 2008): 641–50. http://dx.doi.org/10.1139/e08-018.
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The Gergovie plateau is a Lower Miocene topographically inverted volcano-sedimentary system located in the monogenetic volcanic field of the Limagne rift Tertiary basin. It is composed of three east–west aligned maars partly covered by a basaltic lava flow. The eruption of the central maar (maar 1) occurred at the Oligocene–Miocene transition, during the first volcanic phase. This phreatomagmatic structure was almost totally cut through by the opening of a second maar (maar 2) during the next eruptive phase. The basaltic lava flow at the summit and the eastern maar (maar 3) were placed during a third and last eruptive phase during the Middle or Upper Burdigalian (∼19–16 Ma). Between these periods of volcanism, three fluvial to fluviolacustrine sedimentation episodes, separated by two erosive stages, followed one another. A bedrock thickness of 100–300 m was eroded from maar 2 during the upper Aquitanian and (or) the lower Burdigalian (∼22–19 Ma). This erosion is partly due to a volcano-tectonic uplift in the southern Limagne. The complex morphostructural evolution of the Gergovie plateau demonstrates the north–south geodynamic differentiation of the Limagne rift during the Lower Miocene, since the northern part of the basin corresponded to a relatively calm lacustrine sedimentation area. More generally, the Miocene volcanic field in the South of the Limagne gives an opportunity to study interactions between volcanism, tectonics, and erosion during the late passive rifting activity phase.
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Sanchez, L., and R. Shcherbakov. "Scaling properties of planetary calderas and terrestrial volcanic eruptions." Nonlinear Processes in Geophysics 19, no. 6 (November 6, 2012): 585–93. http://dx.doi.org/10.5194/npg-19-585-2012.
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Abstract. Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.
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Bischoff, Alan, Andrew Nicol, Jim Cole, and Darren Gravley. "Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System." Open Geosciences 11, no. 1 (October 25, 2019): 581–616. http://dx.doi.org/10.1515/geo-2019-0048.
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Abstract Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on the architecture and geological evolution of these basins. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D visualisation of igneous bodies has helped increase knowledge about the architecture of volcanic systems buried in sedimentary basins. Here, we present the complete architecture of the Maahunui Volcanic System (MVS), a middle Miocene monogenetic volcanic field now buried in the offshore Canterbury Basin, South Island of New Zealand. We show the location, geometry, size, and stratigraphic relationships between 25 main intrusive, extrusive and sedimentary architectural elements, in a comprehensive volcano-stratigraphic framework that explains the evolution of the MVS from emplacement to complete burial in the host sedimentary basin. Understanding the relationships between these diverse architectural elements allows us to reconstruct the complete architecture of the MVS, including its shallow (<3 km) plumbing system, the morphology of the volcanoes, and their impact in the host sedimentary basin during their burial. The plumbing system of the MVS comprises saucer-shaped sills, dikes and sill swarms, minor stocks and laccoliths, and pre-eruptive strata deformed by intrusions. The eruptive and associated sedimentary architectural elements define the morphology of volcanoes in the MVS, which comprise deep-water equivalents of crater and cone-type volcanoes. After volcanism ceased, the process of degradation and burial of volcanic edifices formed sedimentary architectural elements such as inter-cone plains, epiclastic plumes, and canyons. Insights from the architecture of the MVS can be used to explore for natural resources such as hydrocarbons, geothermal energy and minerals in buried and active volcanic systems elsewhere.
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Gallagher, V., P. J. O'Connor, and M. Aftalion. "Intra-Ordovician deformation in southeast Ireland: evidence from the geological setting, geochemical affinities and U—Pb zircon age of the Croghan Kinshelagh granite." Geological Magazine 131, no. 5 (September 1994): 669–84. http://dx.doi.org/10.1017/s0016756800012450.
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AbstractThe Croghan Kinshelagh alkali granite intrudes a cleaved volcano-sedimentary sequenceon the border of counties Wicklow and Wexford in southeast Ireland. U-Pb dating of zircons fromthe granite indicate a mid-Caradoc emplacement age of 454 ± 1 Ma. The Duncannon Group hostrocks form the southwestern end of the Avoca Volcanic Belt, a Mid-Ordovician (Caradoc) sequenceof acid and intermediate lavas and volcaniclastics. Dolerite dykes intrude the granite; elsewhere in theregion dolerites are generally associated with volcanic rocks. The main, Dl deformation within theDuncannon Group rocks is manifest as a steep Dl cleavage generally regarded as a product of LateCaledonian regional deformation in southeast Ireland. The Croghan Kinshelagh granite showsstrong geochemical coherence with subalkaline varieties of the Caradoc volcanic rocks; relativelyhigh Th, Y, Nb and REE contents set it apart from any other known granite type in southeastIreland. Together with the geochemical evidence, the age determination of 454 Ma indicates that theCroghan Kinshelagh granite was generated and emplaced during Ordovician volcanism in southeastIreland. Volcanism was closely followed by penetrative deformation and emplacement of the granite.The intra-Ordovician deformation may have been a consequence of closure of the Iapetus Ocean ormore localized events such as accretion on the hanging wall of the subduction zone. The age of theCroghan Kinshelagh granite provides an important datum for Ordovician volcanism and subductionin southeast Ireland.