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1
Rawson, Harriet. "Volcanic history and magmatic evolution of Mocho-Choshuenco Volcano, southern Chile." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:05969e3b-4f38-4478-bc26-381ca13bce1d.
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Active volcanoes pose a significant natural hazard. In order to evaluate the hazard it is important to reconstruct the history of such volcanoes to understand the frequency, style of eruption and the areas typically affected by the explosive eruptions. This thesis focuses on deciphering the volcanic and magmatic record for one of the most productive volcanoes in southern Chile, Volcán Mocho-Choshuenco. Work presented in the thesis establishes a detailed record of the explosive activity during the last 18 kyrs, constructed using field observations and geochemical analyses of the eruption deposits. Using a multi-technique approach Mocho-Choshuenco is shown to be one of the most explosive, frequently active and hence hazardous volcanoes in Chile. This high-resolution eruptive record provides new constraints on the underlying causes of spatial and temporal variability in arc volcanism. Temporally, the record gives new understanding into the response of arc volcanoes to deglaciation; clear temporal variation in eruption flux, eruption size and magma composition are observed. This time-varying behaviour is hypothesised to reflect changes in the crustal plumbing system, and magma storage timescales in response to removal of an ice-load. It demonstrates that deglaciation can drive changes in eruption behaviour at arc volcanoes; however the response is more complex and subtle than settings where decompression melting dominates. Spatially, Mocho-Choshuenco has a high number and density of scoria cones that have erupted relatively primitive magmas but nonetheless with a wide range of magma compositions. For some of the 'classical' slab and mantle geochemical tracers the erupted magmas span the complete range seen in this part of the arc. The tight temporal and spatial constraints provided by the analysed samples, coupled with recent advances in numerical modelling of magma transport through subduction zones, enable new hypotheses for interpreting the signatures of mafic arc magmas to be defined.
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Emery, William Daniel. "Geology and Eruptive History of the Late Oligocene Nathrop Volcanics, Central Colorado Volcanic Field." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1299733477.
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Stock, Michael James. "The volatile history of past volcanic eruptions." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b4fee2ee-f7bc-44f2-9844-7459eb4d975f.
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Volatile elements play an important role in almost every aspect of sub-volcanic systems, from the generation and storage of magma, to the timing and style of volcanic activity. Currently, the most common method for assessing pre-eruptive magmatic volatile contents is through analysis of trapped melt inclusions. However, the reliability of this record is uncertain, necessitating development of new, independent petrologic methods for determining the pre-eruptive volatile contents of past eruptions. This thesis combines physical and chemical models with empirical analyses to develop the use of apatite as a magmatic volatile 'probe'. The first research chapter investigates well-documented difficulties in electron microprobe analysis of apatite volatile concentrations. These are found to be caused by electron-beam induced heating and electric field generation. In determining these effects, it is possible to identify optimal operating procedures for apatite analysis. The next chapter explores the theoretical evolution of apatite volatile compositions as a function of magmatic evolution, building on previous work to develop thermodynamic models that relate crystal compositions to fluid systematics during fractional crystallisation. These provide a qualitative framework for interpreting apatite compositions in natural volcanic systems. The remainder of the thesis is dedicated to identifying new insights that can be gained from the use of apatite as a magmatic volatile 'probe'; this method is applied to constrain pre-eruptive processes at Campi Flegrei, Italy. Texturally-constrained apatite analyses are used to create a time-series of magmatic volatile evolution in the build-up to eruption. This reveals that volatile saturation occurred late in magmatic evolution, and represents a potential eruption trigger. Apatites from different eruptions show a long-term temporal variability in the H2O contents of primitive melts feeding Campi Flegrei, which correlates with different epochs of activity. Melt inclusions from all eruptions have reequilibrated post-entrapment. This study demonstrates the potential utility of apatite for investigating pre-eruptive volatile behaviour in apatite-saturated magmas.
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Meller, Nicola. "The metamorphic history of the Borrowdale volcanic group, North-West England." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390110.
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Smyth, Helen. "Eocene to Miocene basin history and volcanic activity in East Java, Indonesia." Thesis, Royal Holloway, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417139.
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Walker, Cherry L. "The volcanic history and geochemical evolution of the Hveragerði Region, S. W. Iceland." Thesis, Durham University, 1992. http://etheses.dur.ac.uk/5610/.
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The Hveragerði Region is situated at the Hengill Triple junction, SW Iceland, where there are three volcanic systems. The crust in the area is constructed from both fissure (elongate) and lava shield (conical) eruptive units. Hengill is the presently active spreading zone with the Hengill Central Volcano, whereas the Hveragerði region is inactive with the extinct Grensdalur Central Volcano. Recent geophysical research indicates the presence of high and low density volumes within the upper 5 km of the crust in this area. The location of the density anomalies coincides with surface geological features, such as Recent lava shields, and the extinct and active central volcanoes. A geological map of the Hveragerði Volcanic System has been constructed, and approximately 450 basaltic samples have been examined petrographically and analysed for whole- rock, volcanic glass and mineral chemical data from this region. Observations from these data, coupled with the geological and geophysical observations, suggest that the lava shields are fed straight from the base of the crust, whereas fissure eruptions originate from shallow crustal reservoirs The character of the crustal reservoir has been highly variable in the past 1 Ma, and has varied from a melt-dominated reservoir, to a crystal mush-dominated one. Each lava shield is compositionally distinct and is thought to preserve the mantle-melting signature. The compositional variation amongst the lava shields suggests that instantaneous melts are able to segregate from the mantle without complete mixing with accumulated melts from the entire length of the melting column. The depleted instantaneous melts from the crest and top of the melting column will either form picritic lava shields or they may interact with more fractionated crustal reservoirs and undergo quench crystallisation of megacrystic plagioclase (An 80-90). These crystals with associated pyroxene and olivine become flototion cumulates. There are episodes within the stratigraphy where off-axis lava shield and highly megacrystic fissure eruptions dominate, and such periods may represent periods of low magma supply. On the submerged mid-ocean ridges, linear and conical features are also observed, and these may be analogous to the fissure and lava shields, respectively. The basalt types reported here from the Hveragerdi region have also been reported off-shore, and they may therefore represent basalts derived from similar magmatic processes in a similar magmatic plumbing system. However, an initial observation of the relationship of 12 dredged basalts from 63˚ 10'N on the Reykjanes Ridge suggests that this is not the case at this locality.
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Di, Chiara Anita <1983>. "Paleosecular variation of the magnetic field recorded in Pleistocene-holocene volcanics from Pantelleria (italy) and Azores archipelago (portugal): implications for local volcanic history." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5177/.
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The primary goal of volcanological studies is to reconstruct the eruptive history of active volcanoes, by correlating and dating volcanic deposits, in order to depict a future scenario and determine the volcanic hazard of an area. However, alternative methods are necessary where the lack of outcrops, the deposit variability and discontinuity make the correlation difficult, and suitable materials for an accurate dating lack. In this thesis, paleomagnetism (a branch of Geophysics studying the remanent magnetization preserved in rocks) is used as a correlating and dating tool. The correlation is based on the assumption that coeval rocks record similar paleomagnetic directions; the dating relies upon the comparison between paleomagnetic directions recorded by rocks with the expected values from references Paleo-Secular Variation curves (PSV, the variation of the geomagnetic field along time). I first used paleomagnetism to refine the knowledge of the pre – 50 ka geologic history of the Pantelleria island (Strait of Sicily, Italy), by correlating five ignimbrites and two breccias deposits emplaced during that period. Since the use of the paleomagnetic dating is limited by the availability of PSV curves for the studied area, I firstly recovered both paleomagnetic directions and intensities (using a modified Thellier method) from radiocarbon dated lava flows in São Miguel (Azores Islands, Portugal), reconstructing the first PSV reference curve for the Atlantic Ocean for the last 3 ka. Afterwards, I applied paleomagnetism to unravel the chronology and characteristics of Holocene volcanic activity at Faial (Azores) where geochronological age constraints lack. I correlated scoria cones and lava flows yielded by the same eruption on the Capelo Peninsula and dated eruptive events (by comparing paleomagnetic directions with PSV from France and United Kingdom), finding that the volcanics exposed at the Capelo Peninsula are younger than previously believed, and entirely comprised in the last 4 ka.
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Murphy, Michael J. "Geophysical investigation of the tectonic and volcanic history of the Nauru Basin, Western Pacific /." Electronic version, 2004. http://dl.uncw.edu/etd/2004/murphym/michaelmurphy.html.
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Grubensky, Michael J. "Structure, geochemistry, and volcanic history of mid-Tertiary rocks in the Kofa Region, southwestern Arizona." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/558071.
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Morter, Bethany Kathleen. "Understanding the history of a volcanic arc: linking geochemistry of Cenozoic volcanic cobbles from the Wrangell arc, Alaska, to upper plate and subducting slab tectonic processes." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/38164.
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Master of Science<br>Department of Geology<br>Matthew E. Brueseke<br>The Wrangell arc (WA) is a ~29 Ma magmatic belt, extending from south-central Alaska into the Yukon Territory, that lies above the edges and leading front of the Yakutat microplate, a buoyant oceanic plateau that is causing shallow subduction (11-16º) in the region. The WA occurs in a transition zone between “normal” Aleutian subduction to the west and dextral strike-slip tectonics to the east, accomplished by the Totschunda, Denali, and Duke River faults. This geologic setting offers a chance to study the interrelations between subduction, strike-slip motion, and slab-edge magmatic processes in a relatively well-exposed arc. We implemented a novel technique of applying geochemical and geochronologic analyses on volcanic cobbles collected from glacio-fluvial systems (rivers, streams, and glaciers) encircling/draining the WA. Our primary objective is to integrate our cobble datasets with the existing bedrock and detrital sand records to develop a comprehensive understanding of WA magmatism through time and space. Our secondary objective is to test the validity of this novel technique for reproducing what is documented from bedrock samples and its potential for utilization in other locations. This study provides new major element data from 215 samples and trace element data from 236 samples collected from 17 major rivers that drain from the modern western and central WA (this study excludes the eastern WA). This study also provides new age data from a total of 119 samples from 10 major rivers. New geochronology of modern detrital volcanic cobbles and sand/zircons reveal that the WA initiated at ~29 Ma and that magmatism migrated northwestward through time. Cobble ages and locations across the arc agree with the northwestward progression of magmatism previously identified by Richter et al. (1990). Forty-seven cobbles are dated <~1 Ma and only nine cobbles are dated 29 – ~20 Ma, whereas there are no cobbles from 17 – ~13 Ma. Geochemical data reveal similarities between our data and that of the <~5 Ma WA defined by Preece and Hart (2004): Trend 1 (transitional-tholeiitic), Trend 2a (calc-alkaline), Trend 2b (calc-alkaline, adakite-like). Therefore, we use the geochemical framework defined in Preece and Hart (2004) to contextualize spatio-temporal trends of magmatism and tectonic implications in the WA during its ~29 m.y. history. Trend 2a and 2b cobbles are spatially and temporally ubiquitous in the WA, indicating that subduction and partial slab melting have been the dominant tectonic processes throughout WA history. Trend 1 cobbles are not found in southwestern WA rivers and are temporally restricted to ~11 – ~6 Ma and <1 Ma, suggesting intra-arc extension has occurred in discrete periods during WA history. These conclusions are confirmed by the existing (Richter et al., 1990; Skulski et al., 1991; 1992; Preece and Hart, 2004; Trop et al., 2012) and new (Berkelhammer, 2017; Weber et al., 2017) bedrock records. Finally, this study shows that the sampled cobble lithologies largely reproduce the known bedrock record in geochemical, temporal, and spatial contexts, which suggests the novel methodology applied here can be used in other locations where field conditions limit access to bedrock.
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Kraus, Stefan. "Magmatic dyke systems of the South Shetland Islands volcanic arc (West Antarctica) reflections of the geodynamic history /." Diss., [S.l.] : [s.n.], 2005. http://edoc.ub.uni-muenchen.de/archive/00003827/.
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Hobden, B. J. "Modelling magmatic trends in time and space: Eruptive and magmatic history of Tongariro Volcanic Complex, New Zealand." Thesis, University of Canterbury. Geological Sciences, 1997. http://hdl.handle.net/10092/5665.
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Detailed mapping of volcanic stratigraphy in conjunction with 41 new K-Ar ages have been used to constrain a petrological model of Tongariro Volcanic Complex within a time-space framework. Over 400 samples form an extensive geochemical data base comprising whole-rock major and trace element data, together with whole-rock REE and isotopic analyses and mineral compositions for selected samples. These data have been used to investigate the complex interplay between magma batches on a variety of time scales and the time-space relationships of the subvolcanic plumbing system. This new integrated approach to the study of Tongariro has not been applied to many other composite volcanoes but is crucial in linking petrological models to realistic geological relationships.
Tongariro is a large (c.60 km3), active, basaltic andesite to dacite composite cone complex situated near the southern end of the Taupo Volcanic Zone, New Zealand. A virtually continuous eruptive history of the Tongariro complex has been divided into 17 small (<2 km3) to large (12 km3) nested and overlapping volcano-stratigraphic or cone-forming units which represent the products (aa and block lava flows, welded scoria-spatter deposits, volcaniclastic tuff breccias) of many recurrent styles of eruptions from at least 30 discrete vents, active for varying periods of time (a few to tens of thousands of years) throughout Tongariro's known lifetime from c.275 ka to the present. Episodes of rapid cone growth have occurred at 210-200 ka (Tama 2 cone eruptive rate = 1 km3/ka) and 130-80 ka (NE Oturere, SW Oturere and Tongariro Trig cones under construction), with development of the complex most recently dominated by the rapid growth (0.9 km3/ka) of Ngauruhoe cone since 2.5 ka. There is no orderly time-space relationship between cone-building events; the locus of activity shifted non-systematically over the lifetime of the complex within a 13 km-long and 5 km-wide SW-NE aligned vent corridor.
Tongariro eruptive products vary in composition almost continuously from 53.0 to 64.2 wt% SiO2 and 1.1 to 9.2 wt% MgO, forming a calc-alkaline, medium-K suite. Two-pyroxene andesites are volumetrically dominant, but hornblende is a significant phase confined to the older southern cones of Tama 1 and 2 and Pukekaikiore, and olivine is particularly prominent in the young (post-25 ka) eruptives, suggesting an overall time-space relationship with petrography and mineralogy. Tongariro rocks exhibit features typical of subduction-related magmas such as light-REE enriched patterns ([Ce/Yb]N=1.8-3.9), relatively low high field strength abundances (e.g. Nb=2.7-6.7), and strongly spiked patterns on incompatible element spider diagrams. A wide range in 87Sr/86Sr (0.704442 - 0.706193) is accompanied by less variability in 143Nd/144Nd (0.512629-0.512862), Pb isotopic ratios (206Pb/204Pb= 18.781-18.854, 207Pb/204Pb= 15 .594-15.645, 208Pb/204Pb=3 8.5 88- 38.802), and δ 18O (+6.16-6.59).
Variation diagrams for the Tongariro cone-forming units reveal major diversity in the absolute elemental abundances for given SiO2 contents, in the length, steepness and shape of chemical trends, and in the distribution of chemical groups within compositional space. However, certain volcano-stratigraphic units (e.g. the amphibole-bearing andesites of the older southern cones) do share similar patterns of chemical ordering which suggest derivation from a common 'parental' magma reservoir and a similar early history. Nonetheless, considerable chemical variability in closely-related samples is common, and provides strong evidence for a higher level influence on magma compositions. Nonsystematic relationships with age (compositional breaks, reversals and loops) along geoche mical trends on variation diagrams and chemical stratigraphy plots cannot be modelled by fractional crystallization. These coincide with petrographic and mineralogical evidence for disequilibrium including plagioclase sieve textures, strong reverse zoning, coexisting high-temperature and low-temperature phases exhibiting reaction rims or corrosion, olivine phenocrysts with much higher Fo contents than expected from wholerock Mg#, and bimodal or very widely ranging crystallization temperature estimates for some samples. These features suggest the involvement of multiple small batches of magma, rising from the various 'parental' reservoirs by differing ascent paths, within a complex subvolcanic plumbing system which has allowed varying degrees of interaction and magma mixing.
As indicated by the presence of quartzite xenoliths of the Torlesse metasedimentary basement, these magmas have also interacted with the crust, which represents an important means of introducing often wide compositional diversity of magmas on time scales as short as decades or centuries. A considerable variation in incompatible trace element ratios (e.g. Ba/Zr, Nb/Ta, La/Yb, Zr/Hf) and radiogenic isotopic compositions (e.g. Ngauruhoe 87Sr/86Sr ratios increase from 0.705470 in 1954 to 0.706165 in 1975) for closely-related samples, and the marked scatter of data evident on assimilation-fractional crystallization (AFC) process diagrams indicate that magmas have not evolved along a unique AFC trend but can more aptly be characterised as forming a 'family' of AFC trends or perhaps a series of 'one-off AFC 'events' produced by contamination of numerous small and frequent Tongariro magma batches with varying amounts of compositionally heterogeneous Torlesse crust.
This investigation of chemically and isotopically diverse lavas related on time scales of 100 years (historic Ngauruhoe eruptives), 1000 years (Ngauruhoe, Red Crater and Te Mari Crater vents) and 10 000 years (0-10 ka young eruptives, 120-130 ka NE Oturere, 200-210 ka Tama 2) has demonstrated that the observed compositional variability is mainly developed at comparatively high crustal levels within a complex subvolcanic plumbing system by fractional crystallization and the mixing of numerous, small (<<0.1 km3 ), short-lived (c. 1 ka) magma batches coupled with variable amounts of crustal assimilation of a compositionally diverse Torlesse metasedimentary contaminant. These processes have been operating to similar effect throughout the lifetime of the Tongariro complex, although subtle differences in geochemical patterns suggest that the regularity or rate of magma batch production may have varied slightly. The young Ngauruhoe cone has been highlighted as a cameo study for which the well-constrained stratigraphy, enabled by the preservation of numerous young lava flows erupted over the last thousand years, provides a unique opportunity for detailed petrological modelling paying careful attention to age relationships. Five geochemically and isotopically distinct groups of magma reflect variable crustal contamination of many discrete magma batches within several independent shallow plumbing systems beneath Ngauruhoe.
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Rieske, David Eyring. "The depositional environment, provenance and volcanic history of the Paleocene strata of the James Ross Island Basin, Antarctica." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1407506102.
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Munger, Michael, and Michael Munger. "1816: "The Mighty Operations of Nature": An Environmental History of the Year Without a Summer." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12417.
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The catastrophic eruption of the Indonesian volcano Mt. Tambora in April 1815, which ejected a cloud of sulfur dioxide into the upper atmosphere, plunged the world into a rapid temporary climate change event. A series of bizarre weather anomalies, including snowstorms in June and repeated heavy frosts throughout the rest of the summer, earned 1816 the moniker "the Year Without a Summer." This paper examines the various ways in which Americans reacted to the climate change--seeking causation explanations through science and superstition, political and religious responses, and the efforts to appreciate what the events meant in terms of the world's changing climate. Through these various reactions, a picture emerges of Americans' incomplete understanding of science and nature, as well as an uneasy reckoning with the impossibility of fully explaining their environment and the potential dangers it presented to them.
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Tappa, Michael J. Coleman Drew S. "Testing competing caldera models using U/Pb geochronology intrusive history of the Questa caldera, Latir Volcanic Field, New Mexico, USA /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2756.
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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2009.<br>Title from electronic title page (viewed Mar. 10, 2010). "... in partial fulfillment of requirements for the degree of Master of Science in the Department of Geological Sciences." Discipline: Geology; Department/School: Geological Sciences.
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Lion, Allan. "Thermochronologic and Geochronologic Investigations of the Pre-Volcanic Crystalline Basement of Thera (Santorini), Greece: Determining the Tectonostratigraphy and Deformational History of the Metamorphic Core." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38605.
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The cores of most Cycladic Islands are formed as consequences of early Paleogene high-pressure subduction processes of the African plate beneath Europe, and Miocene extensional exhumation of the subduction trench. The island of Thera (Santorini) resides in the Hellenic Volcanic Arc, and is dominated by Quaternary eruptive volcanic material atop a pre-volcanic basement. The position of the island has led to debate as to the nature of the pre-volcanic basement, with connections drawn to either the Cycladic Blueschist Unit (CBU) or the Phyllite-Quartzite Unit (PQU). Field observations, which document a top-to-SSE detachment, in conjunction with geochronological techniques have been applied to assess the tectonostratigraphy of the pre-volcanic basement. The results resolve the pre-volcanic basement as belonging to the CBU which has been juxtaposed against Sub-Pelogonian marble by the SSE directed detachment. This firmly establishes Thera within the Cycladic realm, documents Miocene deformation, and changes the geologic map of the Hellenides.
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Abidin, Hamdan Zainal. "Tectonic history and mineral deposits of the East-Central Kalimantan volcanic belt, Indonesia : a comparative study of the Kelian, Muyup and Masupa Ria gold deposits /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09pha1483.pdf.
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Smith, Peter B. "The alteration history of late Proterozoic Wooltana volcanics, Mount Painter Province, S.A. /." Adelaide, 1992. http://web4.library.adelaide.edu.au/theses/09SB/09sbs656.pdf.
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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology, 1992.<br>National grid reference SH54 - 6737-2. One coloured folded map in pocket inside back pocket. Includes bibliographical references.
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Dávila, Harris Pablo. "Explosive ocean-island volcanism : the 1.8–0.7 Ma explosive eruption history of Cañadas volcano recorded by the pyroclastic successions around Adeje and Abona, southern Tenerife, Canary Islands." Thesis, University of Leicester, 2009. http://hdl.handle.net/2381/9931.
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The 1.8 to 0.7 Ma explosive eruption history of Las Cañadas volcano is recorded by the pyroclastic stratigraphy of southern Tenerife. A large pyroclastic apron is well exposed in the Bandas del Sur. It is divided into two regions, Adeje (southwest) and Abona (southeast). The lower stratigraphy of both successions is described here for the first time, and is divided into soil-bound eruption-units. The lithofacies record repeated phonolite explosive eruptions involving Plinian eruption columns and ignimbrite emplacement, with sedimentary reworking and soilification during repose intervals. The southwestern pyroclastic apron of Cañadas, around Adeje, includes eleven eruption-units, with one explosive eruption every 24,300–31,200 years. Two major unconformities are identified in this region, each representing ~0.6 myr hiatuses. The southeastern pyroclastic apron, around Abona, reveals nine newly discovered phonolitic eruption-units, eight of which are dated by 40Ar/39Ar. The eruptions span 1.6 Ma, and occurred with frequencies averaging one per 21,000 years to one per 79,556 years. The deposits include welded and non-welded ignimbrites and numerous fallout layers. Documentation of the ‘lower’ Bandas del Sur Group allows the entire pyroclastic record of southeast Tenerife to be constrained for the first time: over 18 explosive eruptions occurred during the past 1.6 myr, of which 7 may have been caldera-forming. Eruption frequencies cluster and are separated by unconformities that span from 184,000–563,000 years. A debris-avalanche deposit was discovered on the southeast flank of Cañadas. It records a catastrophic landslide, the Abona landslide, triggered by a phonolite explosive eruption 735 ± 5 ka ago. The Abona debris-avalanche deposit is enclosed between pyroclastic units of the Helecho Formation, and represents a single eruptionunit. Debris avalanche block and mixed facies, and a hummocky topography that dammed small ephemeral perched lakes, are exceptionally well-preserved. Limited disruption and mixing, and a general absence of clast segregation within the deposit, indicate that the landslide did not move as a rapid granular flow. The debris-block characteristics indicate that pervasive shattering and microbrecciation occurred progressively during transport, and were accompanied by limited shear, mixing and substrate erosion during predominantly laminar emplacement of a dilated, but essentially solid, shearing mass. The deposit is the only precisely dated giant landslide on Tenerife and provides the first unequivocal evidence of an eruption trigger on an ocean-island volcano.
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Mas, Magali. "Analyse comparative des représentations du risque volcanique en milieu insulaire : Guadeloupe, Martinique et Réunion." Phd thesis, Université Paul Valéry - Montpellier III, 2012. http://tel.archives-ouvertes.fr/tel-00981943.
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La réduction du risque volcanique dans les départements ultramarins français s'inscrit dans une réflexion plus globale de gestion visant la caractérisation des enjeux et la diminution de leur vulnérabilité. Les îles de la Guadeloupe, la Martinique et la Réunion sont exposées à une multitude de risques naturels de par leur situation géographique et leur caractère insulaire. S'appuyant sur une approche comparative, aussi bien spatiale que temporelle, cette thèse de géographie propose une analyse des rapports des hommes à leur territoire marqué par la présence d'une menace latente : le volcanisme. Dans cette perspective, le risque est appréhendé, non comme un élément extérieur, mais comme un processus de construction sociale. A partir des scénarios éruptifs envisagés par les experts, ce diagnostic évalue, en amont de toute crise, les connaissances, les représentations et les comportements annoncés des populations exposées au risque. Il envisage les déterminants influents, tels le type de volcanisme, l'histoire éruptive ou l'identité des sociétéscréoles. Recenser les distorsions et cerner les réponses inadaptées permet d'envisager des outils d'information préventive plus efficients. Dans la lignée de travaux s'attachant à des thématiques similaires, cette recherche met en exergue la dimension de la composante humaine au coeur de la gestion des risques qu'on a qualifié un peu trop rapidement de "naturels". Au final, nous pointons les atouts à renforcer, les méconnaissances ou croyances à rectifier et les caractéristiques immuables des sociétés créoles, à prendre en compte pour une gestion de crise volcanique optimisée dans le futur.
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Graettinger, Alison Hollomon. "Depositional record of historic lahars in the Whangaehu Gorge, Mt. Ruapehu." The University of Waikato, 2008. http://hdl.handle.net/10289/2336.
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Mt. Ruapehu is one of the most lahar prone volcanoes in the world, having both a crater lake and six small glaciers upon its 2797 m summit. The major outlet for the crater lake, the Whangaehu Gorge, has hosted over 46 historic lahars. However, the low preservation of debris flow deposits, as a result of frequent remobilisation on steep slopes, allows for the detailed description of only 9 lahar events over the last 150 years. Field investigation, historic aerial photos, two airborne LiDAR surveys and direct measurements have been utilised to describe the sedimentology, geomorphology and distribution of historic lahar deposits in the first 11 km of the Whangaehu Gorge. Inundation maps have been created for 1945, 1953, 1975, September 1995, October 1995, March 2007 and September 2007. Grain size distribution, componentry and geomorphology of the 1861, 1975, September 1995, October 1995, 1999 and 2007 lahar deposits have been compared. The lahar deposits are massive, very poorly sorted, silty gravels that form a series of unconsolidated terraces. The limited sediment sources in the steep sided Whangaehu Gorge, including minor historic eruption products, results in significant recycling of lahar deposits. However, the deposits can be differentiated by proportions of lithological components and in some cases anthropogenic debris. The abundance of hydrothermally altered material reflects the role of Crater Lake in lahar formation, although, some of these materials (gypsum, sulphur and snow) are only temporary. Non-cohesive debris flows and occasional snow slurry lahars have been formed by a range of triggering mechanisms associated with and independent of eruptions. Lahars have been formed in the Whangaehu Valley as the result of ejected crater lake water and associated snow melt (1975, September 1995 and September 2007), as well as the progressive displacement of lake water as a result of lava dome growth (1945) and uplift of the lake floor (1968). Inter-eruption lahars occur as a result of Crater Lake outburst floods (1861, 1953 and March 2007) and remobilisation by precipitation and the collapse of tephra laden snow (October 1995 and 1999). The comparison of historic lahars also reflects the range of lahar magnitudes experienced historically on Ruapehu. The most recent Crater Lake outburst of March 2007, with a peak discharge of 1700-2500 m3/s is the second largest recorded lahar, behind only the eruption-generated lahar of April 1975 with a peak discharge of 5000-7500 m3/s. Lahar mitigation can subsequently be based on lahar generation and incorporation of the vast amounts of data collected before and after the 2007 outburst flood. Recent remobilisation and phreatic activity suggest the significant under-representation of small volume events like rain-generated and snow slurry lahars in the geologic record.
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Nelson, Jennifer. "Geology, Geochemistry, and Geochronology of the Nathrop Volcanics: A Comprehensive Look at the History and Formation of Ruby and Sugarloaf Mountains." Bowling Green State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1626900507074039.
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Davis, Michael A. "Jacksonian Volcano: Anti-Secretism and Secretism in 19th Century American Culture." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378109351.
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稲永, 康平, Kohei INENAGA, 充. 奥野 та ін. "熱ルミネッセンス法による九重火山の噴火史の再検討(予報)(第 18回名古屋大学年代測定総合研究センターシンポジウム平成17(2005)年度報告)". 名古屋大学年代測定資料研究センター, 2006. http://hdl.handle.net/2237/13657.
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第18回名古屋大学年代測定総合研究センターシンポジウム平成17(2005)年度報告 Proceedings of the 18th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research
in 2005 日時:平成18 (2006)年1月17日(火)､18日(水) 会場:名古屋大学シンポジオン Date:Januaryl7th and 18th, 2006 Venue:Nagoya Uhiversity Symposion Hall
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Bergström, Marcus. "Explaining Volcanism on Iceland – a review of the Mechanism and Effects of Historic Eruptions." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-229130.
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Iceland is the land-based expression of the Mid-Atlantic Ridge and is one of the most volcanically active regions of the world. Volcanic eruptions on Iceland are a source of geological hazard to humans and the environment due to the release of ash, gases and lava. The composition of the material released is determined by the chemical composition of the surrounding bedrock and the magma upwelling from the Earth’s crust. The effects of historical eruptions on Iceland have been locally devastating and of global impact. The eruption of Lakagígar in 1783-1784 is known to have been the largest eruption in historical time, and is responsible for the death of ~22 % of theIcelandic population. Skeletal fluorosis is a disease that is sometimes observed following large volcanic eruptions. Volcanic ash can travel great distances in the upper atmosphere and spread over vast areas far away from the erupting volcano. Volcanic ash can change incomposition in the atmosphere, and bring about climate-changing effects. Most notably in recent times, violent ash eruptions can also cause problems to the aviation industry, when ash enters and damages airplane engines. Iceland has many active volcanoes and needs to ensure plans for future eruptions are in place. One such measure is an evacuation plan that protects people living close to an active volcano, such as the most lively on Iceland: Hekla, Katla and Eyjafjallajökull.
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Oladottir, Bergrun Arna. "Holocene eruption history and magmatic evolution of the subglacial volcanoes, Grimsvötn, Bárdarbunga and Kverkfjöll beneath Vatnajökull, Iceland." Clermont-Ferrand 2, 2009. http://www.theses.fr/2009CLF21940.
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Dans le but d'étudier l'activité volcanique et l'évolution magmatique des volcans sous-glaciaires de Grimsvötn, Bárdarbunga et Kverkfjöll, des téphras ont été systématiquement échantillonnés au sein de profils établis dans les sols autour du glacier de Vatnajökull en Islande. La composition en éléments majeurs de 921 échantillons de téphra a été analysée par microsonde, ce qui a permis, par comparaison avec la composition chimique des différents produits émis par ces systèmes volcaniques, de déterminer leur provenance. Les nouveaux résultats indiquent 3 groupes de composition distincts, présentant chacun des variations cohérentes avec une évolution cotectique. Si l'identification de ces groupes améliore la distinction compositionnelle entre les produits émis par les 3 systèmes volcaniques étudiés, une légère superposition des compositions demeure néanmoins entre ces différents groupes. L'analyse in situ des teneurs en éléments traces par ICP-MS à ablation laser permet toutefois d'affiner leur distinction. Ensemble, l'analyse des teneurs en éléments majeurs et traces permet d'améliorer significativement l'identification de la provenance des téphras basaltiques holocène qui peuvent avoir des compositions en éléments majeurs similaires autour de Vatnajökull. Régionalement, les profils étudiés dans les sols sont corrélés les uns avec les autres en utilisant des niveaux de téphras marqueurs clefs, et les unités intermédiaires sont corrélées grâce à des outils stratigraphiques et à leur composition chimique. Approximativement, 70% des couches de téphras viennent de Grimsvötn, Bárdarbunga ou Kverkfjöll. La fréquence éruptive de Grimsvötn indique que c'est le système volcanique le plus actif, suivi de Bárdabunga. En revanche, Kverkfjöll présente une activité épisodique avec des périodes de repos supérieures au millier d'années. La diminution de la fréquence éruptive observée il y a 2000-5000 ans dans les 3 systèmes volcaniques, est liée à une diminution de l'activité volcanique et non à des facteurs environnementaux. Pendant la préhistoire, une différence d'âge de 1000-3000 ans a été observée entre les pics d'activité à l'aplomb du panache mantellique (Grimsvötn et Bardarbunga) et les pics d'activité des volcans localisés au sud-ouest, dans la partie hors-rift de la Zone Volcanique Est (ZVE ; e. G. Kalta). Ceci suggère qu'une importante augmentation de l'activité volcanique dans cette partie du ZVE est attendue dans un futur proche car la fréquence éruptive maximum a été observée il y a 1000-2000 ans à Grimsvötn et Bárdarbung. L'évolution magmatique des 3 systèmes volcaniques étudiés est contrôlée par les processus de cristallisation fractionnée et de contamination crustale. Les teneurs en éléments traces indiquent des minéralogies similaires dans les différentes sources magmatiques sous les 3 volcans. Ceci permet alors d'accéder aux conditions relatives de fusion partielle du manteau source : Bárdarbunga à l'aplomb du centre du panache mantellique islandais produit des basaltes issus de plus forts degrés de fusion alors que les plus faibles degrés de fusion sont atteints sous Kverkfjöll, plus loin du centre du panache. Une source magmatique profonde semble avoir joué un rôle important dans l'activité de Grimsvötn et Bárdarbunga, avec un système de sills et dykes plus actif sous le système volcanique de Grimsvötn pendant la période de plus forte fréquence éruptive. Ce système a évolué en chambre magmatique il y a environ 1000 ans, ce qui explique les plus faibles fréquences éruptives observées à cette période. Un lien direct semble lié la fréquence éruptive à l'architecture de la chambre magmatique. Les variations de composition des basaltes issus de Grimsvötn et Bárdarbunga sont consistantes avec la présence d'une chambre magmatique active en profondeur
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Tufano, Antonella. "Les paysages volcaniques : les mythes, la science, l'art." Paris, EHESS, 2000. http://www.theses.fr/2000EHES0097.
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Jordan, Nina Johanna. "Pre-Green Tuff explosive eruptive history, petrogenesis and proximal-distal tephra correlations of a peralkaline caldera volcano, Pantelleria, Italy." Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/32524.
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This study reconstructs the explosive volcanic history of Pantelleria, a peralkaline caldera volcano situated in a rift zone in the central Mediterranean Sea, from the earliest exposed eruption products (~324 ka) to the 46 ka Green Tuff Formation which forms a marker horizon blanketing the entire island. The pre‐Green Tuff stratigraphy has been revised by tracing and logging eruption‐units around the island, making extensive use of coastal cliff sections not reported before. Eight widespread ignimbrite formations have been defined and for the first time have been given type localities. Most ignimbrites are welded and contain lithic breccias. Caldera collapse is thought to have occurred during five of the eight major eruptions and is thought to have re‐used the same scarps multiple times. In interignimbrite repose periods, which last between ~3 and ~52 ka, nearly twenty localised cone or shield‐shaped eruptions have occurred producing mostly pumice falls and lavas of dominantly rhyolitic composition. In contrast, ignimbrites are commonly trachytic but some are strongly zoned and include rhyolitic end‐members. The chemical zonation is more pronounced after longer repose periods. Petrogenetically, the volcano has followed the same liquid line of descent, dominated by fractional crystallisation, throughout its >300 ka history and no recurring chemical cycles have been detected. Calculation of accurate volumes is hindered by the island’s small size, with most eruption products deposited under water. To help constrain eruption volumes, distal ash layers found across the Mediterranean Sea (at up to 1300 km distance: Lesvos, Greece) have been chemically correlated with the proximal eruptions and their volumes calculated to 0.1‐18 km3. Distal ash volumes are up to 45 times larger than onshore volumes for the same formation (0.1‐0.8 km3) and are a powerful tool to complement the proximal record, thereby significantly improving previous volume estimates.
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Dibacto, Kamwa Stéphane. "Dynamique de construction et démantèlement des volcans tertiaires et quaternaires des Carpates par des approches géomorphologiques et géochronologiques Growth and erosion constraints of the East Carpathians volcanoes by numerical models: tectonic and climatic implications Eruptive history of the Late Quaternary Ciomadul (Csomád) volcano, East Carpathians, part II: magma output rates Eruptive history of the Late Quaternary Ciomadul (Csomád) volcano, East Carpathians I: timing of lava dome activity constrained by the unspiked K-Ar method." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS144.
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Dans cette thèse, 47 nouveaux âges ont été obtenus par la technique Cassignol-Gillot. La très bonne reproductibilité des âges obtenus, ajoutée à une stricte cohérence observée entre les édifices volcaniques, supporte l'utilisation de la méthode K-Ar dans la datation des laves des Carpates orientales (Călimani-Gurghiu-Harghita ; CGH) et des dépôts d'ignimbrite du Miocène des Carpates occidentales (les monts de Mátra et Bükk). Dans la partie orientale de la chaîne, les données géochronologiques ont été combinées avec des analyses géomorphologiques pour contraindre l'histoire volcanique et calculer leur taux de construction et d'érosion. Parallèlement, dans la partie occidentale de la chaîne, les données géochronologiques obtenues ont été combinées aux données paléomagnétiques disponibles pour affiner leur stratigraphie. La chaîne des Carpates orientales a connu une migration de son activité éruptive le long de l’arc du Miocène au Quaternaire. Ici, une méthodologie novatrice et complexe apporte de nouvelles contraintes géochronologiques et géomorphologiques sur l'évolution des 20 volcans de la chaîne. Les nouveaux âges ont permis de contraindre leur durée d’activité Par exemple Seaca-Tătarca (6,79-6,47 Ma), Vârghiş (5,47-4,61 Ma) ou de dater l’activité volcanique la plus récente de Călimani. Pour le complexe volcanique de Ciomadul, composé d'une douzaine de dômes de lave, l’activité volcanique a été contrainte entre 704±18 et 28±1ka (<1 Ma) interrompue de périodes de repos. En parallèle, des reconstructions numériques de paléo-topographies volcaniques ont été réalisées dans le but de quantifier leur forme à la fin de leur construction. Les résultats déduits de nos reconstructions ont donné un volume total de matériel émis de 2300km3 sur toute la chaîne avec, à l’échelle de chaque volcan, une large gamme de variation de leur taille (3±3 à 592±115 km³). Ces volumes montrent une nette diminution du nord au sud de la chaîne avec des valeurs de 910, 880, 279 et 165 km³ pour des secteurs géographiques de Călimani, Gurghiu, North Harghita et South Harghita respectivement. Combinés aux âges, ces volumes ont permis de calculer un taux de construction moyen de 200km³/Ma pour toute la chaîne, représenté par deux groupes distincts ; un groupe caractérisé par des taux de construction de 137 km³/Ma caractéristiques des vieux volcans (11-3,6 Ma) suivi d'un groupe avec des taux de construction de 28km³/Ma pour les volcans Plio-Quaternaires. La comparaison des volcans reconstruits et ceux actuels a permis de calculer un volume érodé total de 524±125km³, correspondant à une dénudation moyenne de 22% et à un taux d'érosion moyen de 20m/Ma pour la chaîne de CGH. Suite aux fluctuations climatiques enregistrées le long de cette chaîne, les taux d'érosion caractéristiques de ces grandes périodes climatiques ont été calculés dans le but de montrer le rôle qu’a joué le climat sur les taux d’érosion. Le taux d'érosion le plus élevé de 38m/Ma a été obtenu pour la période régie par un climat continental subtropical modéré transitionnel (9,5-8,2 Ma). Pour la période climatique continentale modérée (8,2-6,8 Ma), caractérisée par des conditions climatiques beaucoup moins humides, un taux d'érosion de 14 m/Ma est proposé. Pour la période correspondant à un climat continental avec identification de périodes semi-arides (6,8-5,8 Ma), un taux d'érosion de 7 m/Ma a été calculé. Pour les volcans Plio-Quaternaires ayant connus des cycles interglaciaires/glaciaires, un taux d'érosion de 28m/Ma a été obtenu. Une telle approche morphométrique et géochronologique quantitative démontre son efficacité à étudier le dynamisme volcanique, y compris les processus de construction et d'érosion au fil du temps. Dans la partie occidentale des Carpates, les âges obtenus sur les coulées de lave de Börzsöny contraignent sa période d'activité entre 14,3-15,1 Ma. Pour les dépôts ignimbritiques de Bükk, les résultats K-Ar évoluent entre 12,7-16,5 Ma<br>In this PhD thesis, 47 new ages have been obtained by the Cassignol-Gillot technique. The very good reproducibility of the ages obtained in this study, added to a strict consistency observed between the volcanic edifices, support the use of the K-Ar method in the dating of the East Carpathian lavas (Călimani-Gurghiu-Harghita) and ignimbrite deposits of the North Hungarian (Mátra and Bükk Mts. [western Carpathians]). In the Eastern part, this new geochronological dataset has been combined with geomorphological analyses to constrain the volcanic history as well as to compute construction and erosion rates of those volcanoes. In parallel, in the western part geochronological dataset has been combined with available paleomagnetic data to refine their stratigraphy. The East Carpathian volcanic range experienced an along-arc, Late Miocene to Quaternary migration of eruptive activity. Here, a novel and complex methodology are presented that yields new geochronological and geomorphological constraints on the evolution of the 20 volcanic edifices. New unspiked K-Ar ages either constrain their lifespan (6.79- 6.47 Ma for Seaca-Tătarca; 5.47- 4.61 Ma for Vârghiş) or date the youngest volcanic activity (central Călimani). For Ciomadul volcanic complex composed by a dozen of lava domes, which hosts the recent volcanic activity since the last 1 Ma, its activity has been constrained between 704± 18 ka and 28 ± 1 ka with several quiescence periods. In parallel, numerical reconstructions of volcanic paleo-topographies were performed to quantify their shape at the end of their construction stage. The inferred initial volcano size shows a wide range (3±3 to 592±115 km³), making up the four main successive volcanic segments (910, 880, 279 and 165 km³ for Călimani, Gurghiu,North Harghita and South Harghita segment, respectively) totalizing 2300 km³. Volume and age constraints allowed computing an average growth rate of 200 km³/Ma for the whole range, characterized by an initial moderate growth rate (137 km³/Ma) of the older volcanoes (11-3.6 Ma) followed by a lower growth rate (28 km³/Ma) obtained for the Plio-Quaternary volcanoes. Comparing reconstructed and current topographies yielded a total eroded volume of 524±125 km³, defining averaged denudation of 22% and a 20 m/Ma erosion rate. Erosion rates for major climatic periods were computed, which highlight the contrasting climatic contexts since 11 Ma. The highest erosion rate (38 m/Ma) occurred during a transitional moderate subtropical continental climate period (9.5-8.2 Ma). An intermediate erosion rate (14m/Ma) characterized a moderate continental climate period (8.2-6.8 Ma) when conditions became less humid. The lowest erosion rate (7 m/Ma) reflects the prevailing continental but occasionally semi-arid climate (6.8-5.8 Ma). The highest erosion rate (28m/Ma) was obtained for Plio-Quaternary times during the interglacial/glacial cycles. Such a quantitative morphometric and geochronological approach demonstrates its efficiency to study volcanic dynamism, including both constructional and erosional processes, through time. In the western part of the Carpathian range, the new ages obtained on the lava flows of Börzsöny made it possible to constraint its period of activity between 14.27 - 15.11 Ma. For the Miocene ignimbrite of Bükk foreland, the new K-Ar results range between 12.7 - 16.5 Ma
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Cadag, Jake Rom David. "A l'ombre du géant aigre-doux. Vulnérabilités, capacités et réduction des risques en contexte multiethnique : le cas de a région du Mont Kanlaon (Philippines)." Phd thesis, Université Paul Valéry - Montpellier III, 2013. http://tel.archives-ouvertes.fr/tel-00985020.
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Les groupes ethniques minoritaires sont parmi les secteurs de la société qui sont menacés en permanence par des risques plus élevés de catastrophes. Le fondement d'un tel constat est les impacts négatifs disproportionnés de catastrophes passées. Il est de ce fait nécessaire d'intégrer tous les groupes ethniques en particuliers les minorités dans la réduction des risques de catastrophe (RRC). Pourtant, la communauté scientifique a peu étudié le rôle de l'ethnicité dans la vulnérabilité et la capacité des populations exposées à divers aléas. Ainsi les praticiens sur le terrain et les organisations non-gouvernementales (ONG), ne possèdent pas de méthodes et d'outils appropriés pour intégrer les minorités ethniques dans la RRC. En plus, des exemples de méthodologies et de politiques visant à rendre cet objectif opérationnel et institutionnalisés sont également limités. Cette étude vise à répondre à ces lacunes, en prenant l'exemple des communautés multiethniques autour de Mont Kanlaon situé sur l'île de Negros aux Philippines. La zone d'étude se caractérise par une grande diversité ethnique composé d'au moins trois grands groupes ethniques (Ilonggos, Cebuanos et Bukidnons). Les résultats de cette étude suggèrent que cette mosaïque constitue une dimension importante de la RRC puisque chaque groupe ethnique possède ses propres formes de vulnérabilité et de capacité face aux aléas volcaniques et d'autres origines. Ces minorités ethniques sont parmi les secteurs les plus vulnérables de la société philippine en raison de leur statut marginalisés. En outre, les résultats de cette étude suggèrent que chaque groupe ethnique possède des capacités issues en grande partie de ressources locales qui sont utiles aux fins de la RRC.
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Gautier, Elsa. "Empreinte isotopique et histoire du volcanisme stratosphérique des 2600 dernières années enregistrées à Dôme C, Antarctique." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAU028/document.
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La glace polaire est sans nul doute la meilleure archive dont nous disposons en terme de paléo volcanisme. Les reconstructions du volcanisme passé se basant sur l'analyse des carottes de glace sont nombreuses. Elles alimentent notamment les modèles de forçage climatique, dans le but d'estimer l'effet refroidissant du volcanisme, dû aux interactions entre aérosols d'acide sulfuriques d'origine volcanique, et le rayonnement solaire incident. Dans ce type de reconstruction, l'un des paramètres-clés pour déterminer l'impact potentiel d'une éruption, est l'identification de son signal sur les deux calottes polaires (signal bipolaire). Cette large répartition spatiale traduit en effet un temps de résidence significatif dans la stratosphère, et donc, un impact climatique important. Les carottes de glace offrent pourtant une alternative intéressante à cette méthode : l'analyse du soufre des sulfates volcaniques révèle la présence d'anomalies isotopiques (Δ33S ≠0) dans les aérosols d'origine stratosphérique, permettant la discrimination entre éruptions de faible impact (troposphériques) et éruptions de fort impact (stratosphériques). L'étude de la signature isotopique atypique des aérosols stratosphériques permet en parallèle de contraindre les mécanismes photochimiques à l'origine de cette anomalie, qui ne sont que partiellement identifiés à ce jour. En 2010-2011, 5 carottes de névé de 100m de long ont été collectées à Dôme C, Antarctique, dans le but de reconstruire une histoire du volcanisme stratosphérique des 2500 dernières années, par la méthode isotopique. Le forage de 5 carottes identiques, à 1 m les unes des autres, nous a permis d'étudier différents aspects de la reconstruction.Premièrement, nous avons pu évaluer la variabilité du dépôt de sulfate à l'échelle locale, et donc, la représentativité statistique d'une seule carotte vis à vis d'une reconstruction volcanique. L'analyse des concentrations de sulfate révèle qu'une importante variabilité locale, associée principalement au déplacement de la neige par le vent, pouvait entraîner un enregistrement non exhaustif des évènements volcaniques (en moyenne 30% d'évènements manquants, par carotte) et une variabilité conséquente du flux archivé (jusqu'à 60%).En second lieu, le niveau de détail de nos analyses (résolution temporelle de chaque éruption) nous a permis de décrire plus précisément la signature des processus indépendants de la masse à l'œuvre dans la stratosphère. Les résultats obtenus ne permettent pas de clore le débat concernant le mécanisme photochimique à l'origine de l'anomalie, mais ils contraignent la signature stratosphérique de façon robuste, notamment en définissant les tendances isotopiques (Δ36S vs. Δ33S et Δ33S vs. δ34S). Les implications de ces contraintes sur la chimie atmosphérique actuelle sont discutées à travers l'utilisation d'un modèle simple ; nous évaluons les paramètres requis, en particulier les proportions des différentes voies d'oxydation stratosphériques (dépendantes et indépendantes de la masse), pour reproduire nos résultats.Enfin, l'analyse systématique de la composition isotopique (Δ33S) des évènements volcaniques nous a permis d'établir un historique du volcanisme stratosphérique enregistré à Dôme C au cours des 2600 dernières années. Nos résultats confirment majoritairement l'origine tropicale (stratosphérique) des évènements identifiés comme tels dans la littérature, et suggèrent le caractère stratosphérique (unipolaire) de quelques éruptions de haute latitude. Les résultats ne remettent pas en question la synchronisation des enregistrements bipolaires récemment établis, et valident l'utilisation de la méthode isotopique pour l'identification des éruptions stratosphériques dans un enregistrement glaciaire<br>Polar ice has proved to be a very valuable way to access Earth's volcanism history, and a large number of volcanic reconstructions are based on ice-core analysis. Reconstructions are fed into climate forcing models in order to estimate volcanic cooling effect, resulting from the interactions between volcanic sulfuric acid aerosols and incident solar radiations. In this type of reconstruction, determining the potential impact of an eruption is a key step. It usually relies on the identification of its signal in both polar caps (bipolar signal). This wide spatial distribution indeed reflects a significant residence time in the stratosphere, and thus a sizable impact on climate. However, ice cores offer an interesting alternative to this method: the analysis of volcanic sulfates reveals a mass independent fractionation of sulfur (S-MIF) in the aerosols formed in the stratosphere, allowing us to discriminate between low climatic impact (tropospheric) and high climatic impact eruptions (stratospheric). Studying the unusual isotopic signature of stratospheric aerosols simultaneously allows for constraining photochemical mechanisms responsible for this anomaly (Δ33S≠ 0), which are currently only partially identified. In 2010-2011, 5 100m-cores were drilled at Dome C, Antarctica in order to reconstruct a history of stratospheric volcanic over the past 2500 years, by the isotopic method. Drilling 5 replicate cores, 1 m apart, allowed us to study various aspects of the reconstruction.Firstly, we were able to assess the sulfate deposition variability on a local scale, and therefore the statistical representativeness of a single core in a volcanic reconstruction. Sulfate concentration analysis of the 5 cores reveals that local scale variability, essentially attributed to snow drift and surface roughness at Dome C, can lead to a non-exhaustive record of volcanic events if a single core is used; on average 30% of the volcanic events are missing per core, and the uncertainty on the volcanic flux (up to 60%) is substantial.Secondly, our detailed analysis (temporal resolution of each eruption) has allowed us to more accurately describe the stratospheric S-MIF signature. Implications on current atmospheric chemistry are evaluated through the set of trends obtained in our samples. We used a simple model implemented with fractionation factors available in the literature to account for the isotopic pattern observed on volcanic sulfate deposition. Through this tool, we evaluated the respective proportions of the different mechanisms assumed to take part in the oxidation process (mass dependent vs. mass independent processes, self-shielding vs. spectral isotopic effect) needed to reproduce natural data, in the current state of experimental knowledge.Finally, the systematic analysis of the isotopic composition (Δ33S) in volcanic events has allowed us to establish a history of the stratospheric volcanism recorded in Dome C in the last 2600 years. Through the isotopic method, in most cases we confirmed the tropical origin of volcanic events as reported in the literature. Discrepancies hinted at high latitude stratospheric events, but the synchronization between North and South Pole records recently established is not questioned. The results also validate the use of the isotopic method to identify stratospheric eruptions in a glacial record
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Pflumio, Catherine. "Histoire volcanique et hydrothermale du massif de salahi : implications sur l'origine et l'evolution de l'ophiolite de semail (oman)." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0112.
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L'etude petrographique et geochimique de l'ophiolite de semail (massif salahi, oman) qui represente le plus vaste affleurement de lithosphere oceanique fossile permet de distinguer 3 phases de volcanisme, presentant des rapports ta/th anormaux qui sont interpretes comme les temoins d'une anomalie mantellaire regionale. Un modele d'evolution en contexte oceanique franc est propose. L'etude des differents episodes de circulation hydrothermale est egalement abordee
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Léocat, Erell. "Histoire éruptive des volcans du secteur occidental des Iles Eoliennes (sud de la mer Tyrrhénienne, Italie) et évolution temporelle du magmatisme." Paris 11, 2010. http://www.theses.fr/2010PA112343.
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Les Iles Eoliennes se construisent sur la marge nord du socle calabro-péloritain dans un contexte de convergence entre les plaques africaine et européenne. Nous nous sommes intéressés aux volcans du secteur occidental des Iles Eoliennes. Ils contiennent une large gamme de magmas typiques des zones de convergence, allant des séries calco-alcalines (CA) aux séries potassiques (KS) en passant par les séries CA riches en potassium (HKCA) et les séries shoshonitiques (SHO). Ces magmas sont émis en moins de 300 ka, ce qui atteste de la complexité de l'évolution volcano tectonique de la province. Trente sept nouvelles données géochronologiques, combinées à une analyse géochimique de soixante treize échantillons et une étude géomorphologique nous ont permis de contraindre l'évolution temporelle du magmatisme et des structures morphologiques. Avant 180 ka, les volcans de Filicudi, Salina et Lipari ont une activité émergée et les magmas émis appartiennent principalement aux séries CA, avec quelques magmas HKCA à Lipari. Après 120-130 ka, les volcans d'Alicudi et Vulcano se construisent aux extrémités Ouest et Sud de l'archipel. Les magmas d'Alicudi sont les plus primitifs de l'archipel. Vulcano et Lipari émettent des magmas HKCA et SHO, alors que des magmas CA sont produits à Filicudi et Salina. Apres 40 ka, Filicudi émet des magmas mafiques HKCA ; Alicudi et Salina des magmas CA ; et Lipari et Vulcano des produits SHO. A l'échelle de l'arc, des variations majeures du chimisme des magmas ont lieu vers 120 et 40 ka et seraient liées à des changements régionaux. A l'échelle locale, l'évolution des magmas est plus complexe et reflète différents processus spécifiques à chaque volcan<br>The Aeolian Islands arc is a complex volcanic province located on the continental margin of the Calabro-Peloritan basement. It emplaced in a geodynamic setting linked to the convergence of African and European plates. In this study, we focused on the western volcanoes of Aeolian Archipelago. They contain the range of geochemical compositions typical of convergence settings, from calc-alkaline (CA) to shoshonitic series (SHO) through high-K CA (HKCA). These magmas were emitted in a short span time of less than 300 ka that attests to the complexity of the volcano-tectonic evolution of this province. We report on thirty seven new geochronological data, on seventy three new geochemical data and on geomorphological analysis to study the temporal evolution of magmatism and of morphological structures. Before 180 ka, only Filicudi, Salina and Lipari volcanoes had emerged activity and emitted CA magmas, with minor HKCA products at Lipari. After 120-130 ka, Alicudi and Vulcano volcanoes emerged simultaneously to the western and southern extremities of the archipelago. Alicudi magmas have the more primitive composition. SHO and HKCA products were emitted on Lipari and Vulcano, while only CA magmas were emplaced on Filicudi and Salina. After 40 ka, Filicudi emitted mafic HKCA magmas while Alicudi and Salina emitted mainly CA magmas. Products of SHO affinity were emplaced at Lipari and Vulcano. At the scale of the archipelago, two main magma composition changes occurred around 120 and 40 ka that would have been caused by regional changes. At the scale of a single volcano, the magmatic evolution is more complex reflecting different processes specific to each volcano
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Benavides, Edgar. "Evolution in Neotropical Herpetofauna: Species Boundaries in High Andean Frogs and Evolutionary Genetics in the Lava Lizard Genus Microlophus (Squamata: tropiduridae): A History of Colonization and Dispersal." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1652.pdf.
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Flores, Espinoza Javier. "Cook, Noble David, con Alexandra Parma Cook. People of the Volcano. Andean Counterpoint in the Colca Valley of Peru. Durham and London: Duke University Press, 2007, xvi + 319 pp., ilustr." Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/121950.
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Germanaz, Christian. "Du pont des navires au bord des cratères, regards croisés sur le Piton de la Fournaise (1653-1964) : itinéraires iconographiques et essai d'iconologie du volcan actif de La Réunion." Paris 1, 2005. http://www.theses.fr/2005PA010594.
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Comprendre comment une représentation spatiale peut devenir un symbole identitaire très fort conduit tout géographe confronté à l'iconographie du Piton de la Fournaise à poser la question de la relation image et savoir géographique. La première étape de cette exploration, mémoire iconographique, présente les modalités, le temps et l'espace du corpus de la Fournaise: le voyage au volcan est un contexte spatial fondateur pour la réalisation des images; les conditions de sa mise en œuvre expliquent la lente constitution des représentations et permettent de discerner les principaux moments de l'histoire iconographique du volcan. La seconde étape investit l'Album de la Fournaise pour retracer les itinéraires iconographiques. La carte offre la première image du volcan et sa participation à la construction d'une représentation savante s'étend sur une longue période. Mais artistes, amateurs passionnés et photographes apportent aussi leur contribution par une illustration souvent très originale. Les différents regards posés sur le volcan sont identifiés à travers six postures analysées par la troisième partie, le volcan sous le regard de l'image. Sur l'ensemble de la période retenue, l'iconographie est une iconographie du réel, très distanciée vis-à-vis d'un imaginaire volcanique encore persistant dans les représentations collectives. Ce souci constant de réalisme a conduit l'iconographie à jouer un rôle efficace dans la construction scientifique de la Fournaise. Sa pertinence dans la révélation et la maturation du paysage volcanique détermine la place qu'elle tient dans la construction du volcan en emblème de l'île.
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Okuno, Mitsuru. "Accelerator Mass Spectrometric Radiocarbon Chronology during the Last 30,000 Years of the Aira Caldera, Southern Kyushu, Japan." 名古屋大学年代測定資料研究センター 天然放射性元素測定小委員会, 1997. http://hdl.handle.net/2237/13346.
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OKUNO, M., S. NAGAOKA, I. TAKASHIMA, et al. "Re-examination of Eruptive History of Kuju Volcano (SW Japan) by Thermoluminescence and Radiocarbon Methods(Proceedings of the 19^ Symposium on Chronological Studies at the Nagoya University Center for Chronological Research in 2006,Part1)." 名古屋大学年代測定資料研究センター, 2007. http://hdl.handle.net/2237/13685.
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第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第1部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research
in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall
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Van, Noord Kenrick A. A. "Deep-marine sedimentation and volcanism in the Silverwood Group, New England Fold Belt, Australia." Thesis, Queensland University of Technology, 1999.
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In eastern Australia, the New England Fold Belt (NEFB) comprises an ancient convergent margin that was active from the Paleozoic until the late Mesozoic. Considerable effort has been expended in understanding the development of this margin over the past twenty years. However, proposed tectonic models for the orogen have either been too broad, ignoring contradictory local evidence, or too locally specific without paying attention to the 'big picture'. The research presented in this work addresses the issue of appropriate scale and depth of geological detail by studying the NEFB at the terrane-scale. Using one succession, the Silverwood Group of southeast Queensland, this work demonstrates that detailed sedimentological studies and basin analysis at the terrane-scale can help to refine hypotheses regarding the tectonic evolution of the NEFB.
The Silverwood Group (Keinjan terrane), located approximately 140 km southwest of Brisbane, Australia, is a succession of arc-related basins that developed within an ancient intraoceanic island-arc during the mid-Cambrian to Late Devonian. From the base of the succession, the group consists of five formations totalling -9700 m. These include the Risdon Stud Formation (2500 m), Connolly Volcanics (2400 m), Bald Hill Formation (2450 m), Ormoral Volcanics (600 m) and the Bromley Hills Formation (1700 m). The Long Mountain Breccia Member (300m) is a separate unit which forms the lower part of the Bromley Hills Formation. The entire succession has been thrust west over the Late Devonian to Early Carboniferous Texas beds. Elsewhere, the Silverwood Group is unconformably overlain by and faulted against Early to Late Permian units including the Rokeby beds, Wallaby beds, Tunnel beds, Fitz Creek beds, Eight Mile Creek beds, Rhyolite Range beds and Condamine beds. Of these Permian units, all but the Condamine beds form part of the Wildash Succession. To the west, southwest and south, the Silverwood Group is intruded by the Late Triassic Herries and Stanthorpe Adamellites. All of these sequences and the two plutonic intrusives are unconformably overlain by the Jurassic sediments of the Marburg Sandstone.
The Silverwood Group and Texas beds consist of various lithologies including grey, purple- grey, green and green-grey volcaniclastic conglomerates, sandstones, siltstones or mudstones, massive and laminated chert, polymict or monomict breccias, muddy breccias, muddy sandstones, and volcanic rocks. Volcanic rocks include various tholeiitic metabasites, dolerite, meta-andesites and infrequent metadacite. In the Silverwood Group, these volcanic rocks are often accompanied by mafic pyroclastic rocks (e.g. peperite and hyaloclastite). Facies analyses of these lithologies has led to the recognition of 19 deep-marine turbiditic and volcanic/volcaniclastic facies that were deposited by three main processes: i) gravity-flow processes (e.g. low- and high-density volcaniclastic turbidites and mass-flows), ii) chemical/biological processes (siliceous oozes- chert) and iii) direct initiation by volcanic processes (e.g. flows, hypabyssal intrusions and associated pyroclastic facies).
For the Silverwood Group, the defined facies occur in distinct vertical associations that form recognisable 3rd and 4th-order architectural elements such as channel, levee, suprafan lobe, outer-fan, basin plain, mass transport complex, volcanic flows, syn-sedimentary sills and syn-sedimentary emergent cryptodomes. These architectural elements are represented in a series of deep-marine depositional environments including slope, shelf-edge failure, submarine-fan and subaqueous basaltic volcanoes. The Risdon Stud Formation and parts of the Connolly Volcanics were deposited along a 'normal' clastic or mud, mud/sand-rich and/or sand/mud-rich slope. Both upper and lower slope environments are represented and in both formations, the slope is speculated to have faced eastwards and prograded away from an active arc located west. Sediments from both successions accumulated at palaeodepths of 1200 to 2000 m.
Although sediments from the upper part of the Bald Hill Formation were also deposited on a slope, these sequences have subsequently collapsed into the depocentre to form extensive slump deposits accompanied by olistoliths of older arc crust. The lower part of the Bald Hill Formation formed by similar processes, although the failure was far more extensive (>20 km along strike). This latter part of the formation is interpreted to be a major shelf-edge failure succession. Upper parts of the Bald Hill Formation also accumulated at palaeodepths of 1200 to 2000 m, but the deposition of these sediments occurred farthest from the shelf and at the greatest depth compared to the Risdon Stud Formation and Connolly Volcanics. Lower parts of the Bald Hill Formation were deposited at palaeodepths of approximately 1700 m.
Subaqueous basaltic volcanoes are prominent in the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics. In the Bald Hill Formation, igneous rocks were emplaced into the shelf-edge failure succession as a series of syn-sedimentary sills and cryptodomes. These high-level hypabyssal rocks occasionally became emergent above the sediment-water interface, whereupon they were partially resedimented. In some parts of the Bald Hill Formation, the hypabyssal intrusions were blanketed by basin plain deposits that are contemporaneous with the slumps and olistoliths in the upper part of the formation. The intrusive rocks were emplaced at 1700 m palaeodepth.
Unlike the Bald Hill Formation, the Ormoral Volcanics and lower parts of the Connolly Volcanics form thick accumulations of extrusive volcanic and pyroclastic rocks that built a significant volcanic pile. Volcanic and pyroclastic facies within these successions were deposited proximal to their source (0-10 km of vent). Extrusive rocks within the Ormoral Volcanics are thought to be derived from intrabasinal fissure-vents located at palaeodepths of 1700 to 3100 m. Igneous rocks from the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics have the petrological and geochemical characteristics of back-arc basin basalts (BAB) that were sourced from undepleted to slightly enriched Fertile MORB Mantle-wedge (FMM). The FMM material was variably enriched in trace elements by fluids derived from the subducting slab prior to emplacement of the igneous rocks. Immediately following emplacement, these rocks were hydrothermally metamorphosed under conditions of low-pressure and transitional low to high-temperature (200-300 °C). By contrast, igneous rocks within the Texas beds lack enrichment in subduction components and are characteristic of N-MORB.
The Bromley Hills Formation is a sand-rich point-source submarine fan deposited at palaeodepths of 500 to 2000 m. The fan was initiated by a mass transport complex resulting from subaerial collapse of a basaltic-andesitic stratovolcano. The submarine fan is characterised by two repetitive stages of retrogressive sedimentation during which channel-levee elements (inner-fan channels) are overlain by suprafan lobe elements (mid-fan) and then by outer-fan deposits as sea-level rises within the depocentre. Both inner-fan channels and suprafan lobes show centralised stacking patterns with limited lateral migration that indicate the depocentre was laterally restricted during sedimentation (e.g. submarine ridges). The Bromley Hills Formation exhibits all the characteristics typical of an active margin fan that formed by a combination of tectonic stage initiation followed by eustatically controlled regressive deposition.
Volcaniclastic sediments of the Silverwood Group range in composition from lithic to lithic- feldspathic wackes and arenites, although they are mainly lithic or feldspathic-lithic wackes and arenites. Many samples are tuffaceous (25-75% pyroclasts), particularly those from the Connolly Volcanics, Ormoral Volcanics and Bromley Hills Formation. Samples in the Bald Hills Formation and Texas beds can be classified as quartz-rich. The majority of the Silverwood Group was sourced from an undissected intraoceanic island-arc, although sediments within the Bald Hill Formation exhibit a provenance that is characteristic of uplift within the arc (recorded as a 'strike-slip continental arc' model). Epiclastic sediments from the Texas beds were sourced from a transitional to dissected continental arc.
Formations of the Silverwood Group were mostly deposited in a series of intra-arc basins within an ancient intra-oceanic island arc, although the lowermost formation developed in a marginal basin (Risdon Stud Formation). All of the basins were located east of the active arc (behind the arc), keeping in mind the present location of the Group relative to the Texas-Coffs Harbour megafold. The entire succession formed during four-phases of arc-related basin development that coincide with major changes in the strain regime of the arc. From the base of the succession, these changes are: I) mid Cambrian to late Silurian marginal basin sedimentation- relative compression within the arc (Risdon Stud Formation), II) late Silurian to Early Devonian intra-arc rifting- relative extension within the arc (Connolly Volcanics), Ill) Early to early Middle Devonian basin collapse followed by intra-arc rifting- relative extension to compression (Bald Hill Formation and Ormoral Volcanics) and IV) early Middle to Late Devonian intra-arc submarine fan sedimentation- relative compression (Bromley Hills Formation).
Comparing the Silverwood Group against equivalent terranes of Cambrian to Devonian age within the New England Fold Belt (NEFB) suggests that the Gamilaroi terrane, Calliope Volcanic Assemblage, Willowie Creek beds and Silverwood Group all formed as one intraoceanic island-arc during the Early to Late Devonian. Prior to this, significant differences in the sedimentological evolution of these terranes suggests that they occupied different positions relative to each other within the one arc. It is proposed that the NEFB formed as a result of dual west-directed subduction zones during the Cambrian to Middle Devonian period. During this time, a single intraoceanic island-arc located seaward of the Australian craton developed above a west-directed subduction zone. This arc was separated from the craton by a marginal sea. A second west-directed subduction zone was located beneath a continental arc developed on the Australian craton. Cambrian to Early Devonian terranes within and along the Peel Fault are proposed to form a part of the ancient subduction zone present beneath the intraoceanic island-arc (Weraerai and Djungati terranes). Collision of the intraoceanic island-arc occurred during the Late Devonian, at which point west-directed subduction occurred beneath the Australian craton and the accreted intraoceanic island-arc. Following collision, a new continental volcanic arc was established that was active during the Late Devonian to Early Carboniferous.
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Kobayashi, Tetsuo, Shinji Nagaoka, Mitsuru Okuno, 哲夫 小林, 信治 長岡 та 充. 奥野. "九重火山の噴火史研究 (レビュー)". 名古屋大学年代測定資料研究センター, 2012. http://hdl.handle.net/2237/18170.
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Richer, Geneviève. "Environnement, représentations, pratiques socio-économiques : phénomènes volcanosismiques et structures agraires en Campanie (IIIe s. av.-IIIe s. n.è.)." Master's thesis, Université Laval, 2006. http://hdl.handle.net/20.500.11794/18139.
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Champion, Emmanuelle. "Fouiller à l'ombre du Vésuve : La contribution des récits de voyage à Pompeï dans la naissance des sciences vulcanologique, archéologique et muséologique entre 1748 et 1901." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR2022.
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En marge des descriptions de Pompéi dans les relations de voyage se cristallisent deux autres récits qui réapparaissent quasi systématiquement dans chaque ouvrage, à savoir celle de l'ascension du Vésuve et celle de la visite du musée de Naples. De la lecture attentive de ces textes et de la récurrence de ces trois sujets complémentaires déroulaient une problématique générale : dans quelle mesure les auteurs de ces récits de voyage ont-ils contribué à la mise en place des sciences archéologique, muséologique et volcanologique ? Néanmoins, le traitement de cette question en trois parties, reprenant les thématiques principales, risquerait de fausser les conclusions et de négliger une perspective interdisciplinaire. L'avènement de ces trois disciplines s’opère au milieu du XVIIIe siècle mais leur définition est progressive et ne s'achève en partie qu'à la fin du XIXe siècle. Du fait de l'importance du cadre chronologique retenu, une connaissance approfondie du site antique, des traditions littéraires du récit de voyage et du contexte (historique, social et culturel) de chaque époque s'imposait. La multiplicité des données mise en relation a permis de dégager des problématiques plus substantielles sans exclure d'informations majeures<br>On the sidelines of the descriptions of Pompeii travel stories, two other accounts almost always appear in each book, namely that of the ascent of Vesuvius and of the visit of Vesuvius and of the visit of the Naples museum. From close reading of these texts and the recurrence of these three complementary topics stemmed one general question: To what extent have these authors travelogues contributed to the development of archaeological science, museology and vulcanology? However, the treatment of this issue in three parts, containing the main themes, could distort the findings and lead us to neglect an interdisciplinary perspective. The advent of these three disciplines takes place in the middle of the eighteenth century, but their definition is progressive and will only be partially completed at the end of the nineteenth century. Because of the importance of the selected time frame, a sound knowledge of the ancient site, the literary traditions of the travel narrative and the context (historical, social and cultural) of each period was required. The multiplicity of data has helped us identify more significant issues without excluding major information
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Furlong, Pierce James. "Aspects of ancient Near Eastern chronology (c. 1600-700 BC)." Melbourne, 2007. http://repository.unimelb.edu.au/10187/2096.
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The chronology of the Late Bronze and Early Iron Age Near East is currently a topic of intense scholarly debate. The conventional/orthodox chronology for this period has been assembled over the past one-two centuries using information from King-lists, royal annals and administrative documents, primarily those from the Great Kingdoms of Egypt, Assyria and Babylonia. This major enterprise has resulted in what can best be described as an extremely complex but little understood jigsaw puzzle composed of a multiplicity of loosely connected data. I argue in my thesis that this conventional chronology is fundamentally wrong, and that Egyptian New Kingdom (Memphite) dates should be lowered by 200 years to match historical actuality. This chronological adjustment is achieved in two stages: first, the removal of precisely 85 years of absolute Assyrian chronology from between the reigns of Shalmaneser II and Ashur-dan II; and second, the downward displacement of Egyptian Memphite dates relative to LBA Assyrian chronology by a further 115 years. Moreover, I rely upon Kuhnian epistemology to structure this alternate chronology so as to make it methodologically superior to the conventional chronology in terms of historical accuracy, precision, consistency and testability.
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Deiana, Denise. "Dall'Ade all'inferno : Genesi e sviluppo della geografia infernale in Occidente tra tardo antico e alto medioevo." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE2063.
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La recherche analyse les représentations de l’enfer à travers l’étude de l’évolution de sa géographie et de sa structure entre l’antiquité tardive et le haut Moyen Âge dans les sources littéraires.La thèse montre comment entre le II et le III après J. C . l’enfer fût employé comme un synonyme d’enfers avec le significat de lieu de l’atteinte du jugement. L’idée de la punition du feu était connue à partir des premières siècles du christianisme avec la parabole du pauvre Lazare et du riche narrée chez l’Evangile de Luc : cette parabole fut employée par les Peres de l’Eglise pour démontrer la séparation entre âmes impies à l’enfer et les âmes justes dans le sein d’Abraham. Par contre, la géographie de l’enfer ne fut pas entièrement décrite et, donc, ne fut pas encore si riche, jusqu’au V siècle, puisque les auteurs préférèrent faire un usage métaphorique de l’enfer, conçu comme un synonyme du mal dans la terre. À partir du V siècle, toutefois, les auteurs commencèrent à s’occuper du destin de l’âme après la mort et donc le représentations de l’enfer devinrent plus claires et caractérisées par une géographie plus définie, comme témoigné par des texte comme la Visio Pauli et les prédications de Faust de Ries et Augustin. À partir du VI siècle, avec Grégoire le Grand, l’enfer fut représenté comme le lieu de la damnation éternelle, surtout grâce à l’usage des modèles de la tradition ancienne et à l’association avec des lieux de la terre, comme les volcans de la Sicile, avec l’objectif de démontrer la vie de l’âme dans l’au-delà. Avec les visions du VII et VIII siècles la structure et la géographie de l’au-delà furent plus définies ensuite à sa division en trois parties, avec l’adjonction du purgatoire. Les auteurs du VII et VIII siècles employèrent des éléments et des imagines de la tradition précédente pour la représentation de l’enfer<br>The research analyzes the representations of hell through the study of the evolution of its geography and its structure between late antiquity and the early middle ages in the literary sources. It is highlighted how in an era between the second and fifth centuries A. D. the hell was used as a synonym for inferi with the meaning of a place of waiting before the final judgment. The idea of the punishment of fire after death was already known from the early centuries of Christianity with theparable of Lazarus the poor and the rich man, narrated in the Gospel of Luke: this parable was used by the Church Fathers to demonstrate the separation between wicked souls in hell and right souls placed in the bosom of Abraham. The geography of the underworld, however, was not fully described until at least the fifth century, because the authors preferred a metaphorical use, which represented hell as synonymous of evil and sin. Starting from the fifth century with greater attentionto the destiny of the soul in the moment following death, the descriptions of hell became clearer and characterized by a more defined geography, as evidenced by the text of Visio Pauli, Augustine and Faustus's preaching. From the sixth century, and in particular with pope Gregory the Great, hell was definitively represented as the seat of eternal damnation, also thanks to the help of models belonging to the ancient tradition and the association with some places on earth, such as the volcanoes of Sicily, all being used as an important political tool which the papacy appropriated to explain the activity of the soul in the otherworld, against an environment who denied it. With the visions of the seventh and eighth centuries, finally, the structure and geography of hell became more complicated and defined in three spaces, because the authors added the purgatory space. To describe the otherworld the visions of the seventh and eight centuries used the pictures and themes already employed in the previous centuries
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Konaré, Alhousseyni. "Mystique et prophétie chez Léopold Sédar Senghor et Aimé Césaire." Paris 4, 1986. http://www.theses.fr/1986PA040286.
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"Volcanic History of the Tempe Volcanic Province." Master's thesis, 2012. http://hdl.handle.net/2286/R.I.15894.
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abstract: Tempe Terra, Mars, has a complex history marked by volcanism and tectonism. Investigation results presented here build on previous work to better determine the volcanic history of the Tempe volcanic province by identifying and mapping previously undetected vents, characterizing all vents, identifying spatial and temporal trends in eruptive styles, comparing vent density to similar provinces such as the Snake River Plains of Idaho and Syria Planum and determining absolute age relationships among the volcanic features. Crater size-frequency distribution model ages of 120 Ma to 2.4 Ga indicate the province has been active for over half of the planet's history. During that time, age decreases from southwest to northeast, a trend that parallels the dominant orientation of faulting in the region, providing further evidence that volcanic activity in the region is tectonically controlled (or the tectonics is magmatically controlled). Morphological variation with age hints at an evolving magma source (increasing viscosity) or changing eruption conditions (decreasing eruption rate or eruption through thicker lithosphere).<br>Dissertation/Thesis<br>M.S. Geological Sciences 2012
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Saginor, Ian. "Volcanic history of western Nicaragua and geochemical evolution of the Central American volcanic front." 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17561.
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Kern, Jamie M. "Timescales of large silicic magma systems : investigating the magmatic history of ignimbrite eruptions in the Altiplano-Puna Volcanic Complex of the Central Andes through U-Pb zircon dating." Thesis, 2012. http://hdl.handle.net/1957/30153.
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The Altiplano-Puna Volcanic Complex in the Central Andes is one of the youngest large silicic volcanic fields (LSVFs) in the world, erupting over 13,000 km³ of material during multiple supereruptions from 11 to 1 Ma. Understanding the timescales over which magma is stored in the crust prior to eruption is crucial to understanding the development of LSVFs such as the APVC. The residence time of a magma is defined as the time between magma formation and its eruption. While the eruption age of a volcanic system is generally well constrained through ⁴⁰Ar/³⁹Ar dating of sanidine and biotite crystals, determining the time of magma formation offers a bigger challenge. U-Pb dating of zircon—an early crystallizing, ubiquitous phase in silicic systems—is a commonly used method for determining the timing of magma formation.
U-Pb zircon ages were collected for 16 ignimbrites representing the temporal and spatial distribution of the APVC. Zircon crystallization histories show significant overlap between eruptive centers of similar age separated by as much as 200 km. Ignimbrites erupted from the same multicyclic caldera show little relationship. This suggests that ignimbrites may share a deeper, regional source. Timescales of zircon crystallization for individual ignimbrites range from ~400 ka to more than 1 Ma, with little correlation with age or erupted volume. Ignimbrites with longer crystallization timescales frequently exhibit a stepped age distribution and highly variable U contents, suggesting that these ignimbrites likely formed in a very crystalline, low melt fraction environment while ignimbrites with short crystallization times and constrained U concentrations crystallized in high melt fraction systems. Zircon crystallization histories record periods of continuous zircon crystallization in the APVC that extend over 1.5-2 Ma pulses and correlate well with eruptive pulses recognized by previous studies.
Overall, zircon crystallization histories of the magmas feeding ignimbrite eruptions in the APVC record long timescales of magmatic activity from a shared regional source, likely the Altiplano-Puna Magma Body currently detectable underlying the APVC.<br>Graduation date: 2012
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Kraus, Stefan [Verfasser]. "Magmatic dyke systems of the South Shetland Islands volcanic arc (West Antarctica) : reflections of the geodynamic history / von Stefan Kraus." 2005. http://d-nb.info/975570803/34.
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Patia, Herman. "Petrology and geochemistry of the recent eruption history at Rabaul Caldera, Papua New Guinea : implications for magmatic processes and recurring volcanic activity." Master's thesis, 2004. http://hdl.handle.net/1885/7345.
Full textAbstract:
The initial phase (Phase 1 - 19 September 1994 to 16 April 1995) of the current
(1994-2003) eruption at Rabaul Caldera occurred with synchronous vulcanian and
vulcanian-plinian eruptions from Tavurvur and Vulcan, respectively, on opposing sides of the caldera. A second phase of activity (Phase 2), beginning on 28 November 1995 and
continuing until the present (2003), is characterised by intermittent vulcanian and
strombolian eruptions that are restricted to Tavurvur, on the northeastern side of Rabaul
Caldera...Comparison with dacite magma compositions erupted in 1937-1943, 1878, and
during the recent prehistoric era and the presence of plagioclase phenocrysts reflecting older basalt-dacite magma interaction events (i.e., anorthite cores overgrown with thick andesine rims). The petrologic and geochemical observations made in this study indicate the shallow magma system at Rabaul Caldera has been subject to repeated mafic magma injection since, and also during, the latest caldera-fonning eruption about 1400 years BP. The frequency and repeated occurrence of these injections may maintain a near steadystate system that is characterized by the persistent eruption of similar, crystal-poor dacite compositions over the last 1400 years, and the presence at shallow level of a large volume of dacite magma beneath Rabaul Caldera (Finlayson et al., 2003; Mori et al., 1989).<br>The Australian overseas Aid Agency (AusAID), in the form of an AusAID Scholarship Award. The ACT branch of the Geological Society for funding my participation at the 16th Australian Geological Convention held in Adelaide in July 2002. The Department of Mining for paying for air tickets and allowance for my family.