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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Temporal changes of shear wave velocity and anisotropy in the shallow crust induced by the 10/22/1999 m6.4 Chia-yi, Taiwan earthquake

Chao, Tzu-Kai Kevin 09 April 2009 (has links)
Temporal changes of seismic velocity and anisotropy in the shallow crust are quantified using local earthquakes recorded at a 200-m-deep borehole station CHY in Taiwan. This station is located directly above the hypocenter of the 10/22/1999, M6.4 Chia-Yi earthquake. Three-component seismograms recorded at this station show clear direct (up-going) and surface-reflected (down-going) P- and S-waves, and S-wave splitting signals. The two-way travel times in the top 200 m is obtained by measuring the time delays between the up-going and down-going waves in the auto-correlation function. The S-wave travel times measured in two horizontal components increase by ~1-2% at the time of Chia-Yi main shock, and followed by a logarithmic recovery, while the temporal changes of S-wave splitting and P-wave are less than 1% and are not statistically significant. We obtain similar results by grouping earthquakes into clusters according to their locations and waveform similarities. This suggests that the observed temporal changes are not very sensitive to the seismic ray path below CHY, but are mostly controlled by the variation of material property in the top 200 m of the crust. We propose that strong ground motions of the Chia-Yi main shock cause transient openings of fluid-filled microcracks and increases the porosity in the near-surface layers, followed by a relatively long healing process. Because we observe no clear changes in the shear wave anisotropy, we infer that the co-seismic damages do not have a preferred orientation. Our results also show a gradual increase of time delays for both the fast and slow S-waves in the previous 7 years before the Chia-Yi main shock. Such changes might be caused by variations of water table, sediment packing or other surficial processes.
132

Early Archaean crustal evolution: evidence from ~3.5million year old greenstone successions in the Pilgangoora Belt, Pilbara Craton, Australia

Green, Michael Godfrey January 2001 (has links)
In the Pilgangoora Belt of the Pilbara Craton, Australia, the 3517 Ma Coonterunah Group and 3484-3468 Ma Carlindi granitoids underlie the 3458 Ma Warrawoona Group beneath an erosional unconformity, thus providing evidence for ancient emergent continental crust. The basalts either side of the unconformity are remarkably similar, with N-MORB-normalised enrichment factors for LILE, Th, U and LREE greater than those for Ta, Nb, P, Zr, Ti, Y and M-HREE, and initial e(Nd, Hf) compositions which systematically vary with Sm/Nd, Nb/U and Nb/La ratios. Geological and geochemical evidence shows that the Warrawoona Group was erupted onto continental basement, and that these basalts assimilated small amounts of Carlindi granitoid. As the Coonterunah basalts have similar compositions, they probably formed likewise, although they were deposited >60 myr before. Indeed, such a model may be applicable to most other early Pilbara greenstone successions, and so an older continental basement was probably critical for early Pilbara evolution. The geochemical, geological and geophysical characteristics of the Pilbara greenstone successions can be best explained as flood basalt successions deposited onto thin, submerged continental basement. This magmatism was induced by thermal upwelling in the mantle, although the basalts themselves do not have compositions which reflect derivation from an anomalously hot mantle. The Carlindi granitoids probably formed by fusion of young garnet-hornblende-rich sialic crust induced by basaltic volcanism. Early Archaean rocks have Nd-Hf isotope compositions which indicate that the young mantle had differentiated into distinct isotopic domains before 4.0 Ga. Such ancient depletion was associated with an increase of mantle Nb/U ratios to modern values, and hence this event probably reflects the extraction of an amount of continental crust equivalent to its modern mass from the primitive mantle before 3.5 Ga. Thus, a steady-state model of crustal growth is favoured whereby post ~4.0 Ga continental additions have been balanced by recycling back into the mantle, with no net global flux of continental crust at modern subduction zones. It is also proposed that the decoupling of initial e(Nd) and e(Hf) from its typical covariant behaviour was related to the formation of continental crust, perhaps by widespread formation of TTG magmas.
133

Din?mica de reprodu??o e comportamento reprodutivo de branchoneta Dendrocephalus brasiliensis Pesata, 1921 como incremento na produ??o de alimento vivo para peixes ornamentais

Lopes, Jos? Patroc?nio 21 December 2007 (has links)
Made available in DSpace on 2014-12-17T15:36:32Z (GMT). No. of bitstreams: 1 JosePL.pdf: 882497 bytes, checksum: cb18f10b1c9406dc277552138c430082 (MD5) Previous issue date: 2007-12-21 / Reproductive behavior of Dendrocephalus brasiliensis Pesta, 1921(Crustacean: Anostracan). The reproductive behavior of fresh water Anostracan has been poorly investigated in carcinology specialized literature, specifically in relation to Dendrocephlaus brasiliensis Pesta, 1921, with abundant data just about the geographical distribution of that Anostracan. The objective of this work was to know the reproductive behavior of this Anostracan, in different seasons (dry and raine). For this, ripe individuals of both sexes were collected in four pond of the of Fish farming Station of Paulo Afonso (EPPA), through monthly captures in each ponds, from December 2004 to November 2005. The type of reproduction was observed after the placing in aquariums (a) of then with males and (b) other on individually, at the nauplii phase, where they stayed for 15 days until the reproductive age. The sexual proportion was calculated through the relative frequencies of males and females, every month, for the whole collection period during 10 days. the production of cysts was related to the size of the female. The male: female ratio in the study period was 1 male:1,07 female. The proportion male:female was from 48,25% : 51,75% along the year. Concerning the type of reproduction, it was observed that this specie is characteerized by sexual reproduction / O comportamento reprodutivo de anostr?ceos de ?gua doce tem sido pouco divulgado na literatura especializada em carcinologia, especificamente em rela??o a Dendrocephlaus brasiliensis Pesta, 1921, havendo apenas dados abundantes sobre a distribui??o geogr?fica desse anostr?ceo dulciaqu?cola. O objetivo deste trabalho foi conhecer o comportamento reprodutivo deste an?straceo, em diferentes per?odos (seco e chuvoso). Para isto, foram utilizados indiv?duos maduros de ambos os sexos coletados em quatro viveiros da Esta??o de Piscicultura de Paulo Afonso (EPPA), atrav?s capturas mensais em cada viveiro, durante o per?odo de dezembro de 2004 a novembro de 2005. O tipo de reprodu??o foi observado atrav?s da coloca??o simult?nea em aqu?rios de algumas f?meas e machos, e outras individualmente a partir da fase de n?uplios, onde permaneceram por 15 dias at? a idade reprodutiva. A propor??o sexual dos indiv?duos foi calculada atrav?s das freq??ncias relativas de machos e de f?meas, a cada m?s, para todo o per?odo de coleta. Aos 10 dias, ? poss?vel a produ??o de cistos e o n?mero destes est? relacionado ao tamanho da f?mea. A rela??o macho:f?mea no per?odo de estudo foi de 1 macho para 1,07 f?mea. A propor??o macho: f?mea foi de 51,75% de f?mea para 48,25% de machos ao longo do ano. Quanto ao tipo de reprodu??o, foi observado tratar-se de reprodu??o sexuada
134

3D structure of the crust and upper mantle beneath Northern Fennoscandian shield

Silvennoinen, H. (Hanna) 02 December 2015 (has links)
Abstract The crustal and upper mantle structures of the Shield on the regional scale were investigated using the data of the POLENET/LAPNET passive seismic array and the previously published models of active and passive seismic experiments in the study area. This area is centred in northern Finland and it extends to surrounding areas in Sweden, Norway and northwestern Russia. The bedrock there is mostly of the Archaean origin and the lithosphere of the region was reworked by two orogenies during Palaeoproterozoic. One of the results of the thesis was a new map of the Moho depth of the study area, for which new estimates of the crustal thickness were obtained using receiver function method and complemented by published results of receiver function studies and controlled source seismic profiles. The map differs from the previously published maps in two locations, where we found significant deepening of the Moho. The 3D structure of the upper mantle was studied using teleseismic traveltime tomography method. The resulting model shows high seismic velocities below three cratonic units of the study area, which may correspond to non-reworked fragments of cratonic lithosphere and a low velocity anomaly separating these cratonic units from each other. The regional scale studies were complemented by two smaller scale studies in upper crust level using combined interpretation of seismic profiling and gravity data. These studies were centred on Archaean Kuhmo Greenstone Belt in eastern Finland and central Lapland in northern Finland located in the crust reworked during Palaeoproterozoic. Both areas are considered as prospective ones for mineral exploration. Both studies demonstrate the advantage of gravity data inversion in studying 3D density structure of geologically interesting formations, when the Bouguer anomaly data is combined with a priori information from petrophysical and seismic datasets.
135

Le Cénozoïque du bassin de Paris : un enregistrement sédimentaire haute résolution des déformations lithosphériques en régime de faible subsidence / The Cenozoic of the Paris basin : a high resolution sedimentary record of lithospheric deformation in low subsidence context

Briais, Justine 23 January 2015 (has links)
Le bassin de Paris est considéré comme un exemple typique de bassin intracratonique (sag) affecté par une subsidence thermique long terme. Le Cénozoïque correspond à une période de faible subsidence (épaisseurs inférieures à 350m) et marque la fin du fonctionnement de ce bassin. C'est en outre une période de forte déformation de la plaque européenne, dans un contexte de convergence Afrique-Eurasie et d'ouverture de l'Atlantique Nord caractérisée par des inversions de grabens dans le Nord et l'Est de l'Europe. Si de nombreux hiatus ont été identifiés, les déformations cénozoïques du bassin de Paris, situées sur une croûte à l'équilibre et leur relation aux contraintes en limite de plaque restent méconnues. Cette thèse a pour objectif de recomposer à haute résolution spatiale et temporelle (de l'ordre du million d'années) les géométries sédimentaires 3D et les paléogéographies successives du Paléocène au début de l'Oligocène. Ce travail qui s'appuie sur de nombreuses données biostratigraphiques consiste en une approche couplée de sédimentologie de faciès et de corrélations diagraphiques (500 puits) selon les principes de la stratigraphie séquentielle. Trois ordres de séquences sont définis. Les cycles d'ordre supérieur (4ème et 3ème ordre) enregistrent les variations climato-eustatiques. Cinq séquences de dépôt (2e ordre), limitées par des discontinuités et/ou des réorganisations paléogéographiques sont identifiées : (1) Maastrichtien-Danien ; (2) Thanétien-Yprésien ; (3) Lutétien-Bartonien ; (4) Bartonien-Priabonien terminal et (5) Priabonien terminal-Chattien. Les architectures des séquences (1) à (4) sont contrôlées par des phases de flexures. Après des émersions lors des paroxysmes de flexuration, la relaxation progressive des flexures se traduit tout d'abord par la mise en place de profils pentés et ouverts, puis par des profils de plus en plus plats et confinés associés à une transgression généralisée. Du Thanétien au Bartonien s'observent des flexures d'axe E-W, dont les âges sont compatibles avec les différentes phases de la convergence Ibérie-Eurasie. En outre, une déformation de courte durée à l'Yprésien basal est rattachée à l'ouverture de l'Atlantique Nord. Enfin, une réorientation majeure du bassin possiblement liée au début de la collision Apulie-Eurasie est observée au Priabonien. Ce travail fournit un calage à haute résolution pour la compréhension et la modélisation des déformations intraplaques. Différentes tailles de flexure, de l'ordre de 150 à plus 300 km sont observées traduisant une implication d'épaisseurs plus ou moins importantes de la lithosphère. / The Paris basin is currently considered as a typical example of intracratonic basin (sag) affected by long term thermal subsidence. The Cenozoic is a period a low subsidence (less than 300m thick) and correspond to the end of the Paris basin sedimentation. Moreover, it is a period of strong deformation of the European plate related to Africa Europe convergence and North Atlantic opening, well known through numerous grabens inversions in northern and eastern Europe. While hiatus have been highlighted within Paris Basin sedimentation, cenozoic deformations of this thicker crust basin still poorly known. This thesis aims at recompose high resolution temporal and spatial evolution of 3D sedimentary geometries and palaeogeographies from Thanetian to Lower Oligocene. This work is firstly based on available and newly acquired biostratigraphic data. Facies sedimentolgy and well data correlations based on sequence stratigraphy principles allowed to recompose the basin evolution at 1Ma timescale. 2 orders of sequences were identified. Third order sequences (1My duration) seems to be controlled by climate-eustasy. Five main (2nd order) sequences bounded by unconformities and/or palaeogeographic reorganization are highlighted : (1) Maastrichtian-Danian ; (2) Thanetian-Ypresian ; (3) Lutetian-Bartonian ; (4) Bartonian-top Priabonian et (5) Top Priabonian-Chattian. Sequences 1 to 4 correspond to basin scale flexure which control their architecture. Following emersion during the main flexural phases, flooding start with relatively steep depositional profiles. As flexure progressively relax, flatter depositional profiles take place together with overall transgression. This work yield high resolution constraints for the understanding and thermomechanical modelling of intraplate deformations various lenght of flexures form 150 to 300km and more are identified and traduces different thickness of deformed lithosphere. From Thanetian to Bartonian, successives E-W oriented flexures take place which ages are congruent with the main phases of Iberia-Eurasia convergence. A short term deformation in basal Ypresian is attributed to the onset of North Atlantic opening. Finally major basin-scale reorientation during Priabonian could be linked to the onset of Apulia- Eurasia continental collision.
136

Teleseismická tomografie svrchního pláště pod Českým masívem / Teleseismic Tomography of the Upper Mantle beneath the Bohemian Massif

Karousová, Hana January 2014 (has links)
Passive seismic experiments, MOSAIC, BOHEMA I-III, EgerRift, or, PASSEQ, carried out in the region of the Bohemian Massif (BM), allowed a detailed study of velocity structure of the upper mantle. We present results of tomography studies of the upper mantle beneath the north-eastern and southern parts of the BM based on the data from the BOHEMA II and BOHEMA III experiments (2004-2006). Despite the fact that regions with the highest resolution of velocity perturbations differ in the models, tomography images are similar in overlapping parts. Models of the upper mantle show mostly low- velocity perturbations relatively to radially symmetric velocity model of the Earth beneath the BM. Limited high-velocity heterogeneity beneath the Moldanubian unit, extended in the NE-SW direction, reflects thickening of the lithosphere due to a collision of the BM with the Brunovistulian micro-plate during the Variscan orogeny. The tomography based on the data from the BOHEMA III experiment revealed significant high-velocity heterogeneity in the southern margin of the model with a subduction of the lithosphere beneath the Eastern Alps. Tomographic tests showed that effects of uncorrected velocity heterogeneities within the crust can appear as deep as 100 km and, therefore, they could lead to erroneous interpretation of...
137

Vliv vodní eroze na vybrané fyzikální vlastnosti půdy / Effects of water erosion on selected physical properties of soil

Larišová, Lucie January 2018 (has links)
The aim of the dissertation thesis is the assessment of the degradation of selected soil properties due to water erosion, including the temporal dynamics of these properties and the assessment of how this change affects the cumulative infiltration of the soil in watershed. Between 2012 and 2015, undisturbed and disturbed soil samples were collected on three experimental areas and the cumulative infiltration of the soil was measured. Experimental areas were selected on sloping, erosion-endangered blocks of arable land, in three cadastral territories of the Czech Republic, and this in the cadastral areas of Větřkovice, Čejkovice and Hustopeče. The cumulative infiltration was measured in three landscapes positions of the slope and soil samples were collected in three landscapes positions of the slope, at soil crust, topsoil and subsoil. In the Pedological Laboratory at the Institute of Landscape Water Management, Brno University of Technology, the particle density, bulk density, porosity, soil texture and water stable aggregates were determined from the samples taken. The cumulative infiltration of the soil was measured using the Double Ring Infiltrometer, the Mini Disc Infiltrometer and the mobile rainfall simulator. Using one-way analysis of variance to analyze the differences among soil samples and infiltration test. In addition, the dependence of soil crust formation, its physical properties and its influence on the cumulative infiltration of the soil were monitored on the areas.
138

Apatite, allanite, titanite and monazite characteristics in S-, I- A-type Cape Granites

Spicer, Esme M. (Esme Marelien) 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: This study focussed on the comparison of accessory mineral chemistry and paragenesis in the S-, I- and A-type granites of the Cape Granite Suite. The objective of the study was to use differences in accessory mineral chemistry and petrography to give insight in the evolution, recycling and formation of continental crust as affected by the Cape Granite Suite. Because of the high partition coefficients of the REE and trace elements into accessory minerals these minerals play an important role to explain granite evolution. The accessory mineral features are used as discriminators between barren and mineralized S-, I- and A-type granites in the suite. The petrography of the suite reflects the allanite-monazite dichtonomy with allanite and titanite occurring in the I -type granites while monazite occurs in S-type granites. Monazite becomes unstable in high Ca melts such as I-type granites. Apatite occurs in all the plutons which reflects its stability over a wide range of geological conditions. Rounded crystal habits of apatite and monazite in S-type granites indicate they are relics of sedimentary source rocks. Concentric growth- and sectoral zoning, as observed with CL and SEM, are common features in minerals that crystallized in barren plutons. The overprinting of magmatic textures reflects secondary processes, such as those that occurred in mineralized plutons, by "patchy" zoning and irregular alteration rims (coronas) in the mineralized plutons' accessory minerals. CL and SEM observations revealed that REE are redistributed into these coronas. Mineral chemistry of the accessory minerals reflects mostly the whole rock chemistry and physical conditions of the magmas. (Al~ Fe) substitution in titanite is controlled by P-T conditions, together with Ca, Mn and Mg substitution which is controlled by whole-rock chemistry, are good discriminators in S- and I-type granites. LREE and Sr content in allanite discriminate between the plutons and reflect the whole-rock chemistry. Apatite, because it occurs in all the plutons, is the most useful accessory mineral for discriminating between the plutons. From previous studies it is known that ASI controls the two main substitutions in apatite: Ca+P~Si+REE and Na+REE~2Ca, Fe and Mn content in apatite (0,1 pfu Mn and 0,05 pfu Fe contents are the cut-off between S-and Itype granites) are controlled by oxidation state of the magma and Sr, REE and Mg reflect whole-rock chemistry. The content of these elements in apatite can be used as discriminators between the plutons as their ASI, oxidation states and whole-rock chemistry differ. REE patterns of monazite and allanite are LREE enriched without exception, while apatite and titanite REE patterns are mostly birdwing profiles with occurrences of LREE or HREE enrichment. These patterns are influenced by crystallization of coexisting REE-bearing phases, fractionation history of the pluton and by crystallization sequence of the accessory minerals. Phase relationships were investigated experimentally for monazite and allanite under magmatic conditions (870 °C, 1,8 kbar) in peraluminous to metaluminous granitic melts. Monazite became unstable when aqueous CaCh solutions of 0.7-7 g CaCh/10cc H20 where added to peraluminous melts (ASI> 1 ). Monazite broke down to Cl-apatite and corona textures were observed. Allanite was tested in peraluminous (ASI> 1) and metaluminous (ASI=1) melts with different P20 5 (0.08 - 0.25 wt%) concentrations. Allanite became unstable at high phosphorus and peraluminous melt conditions and broke down to LREE-P± Al, Ca, K phases. Corona (kelyphitic) textures were observed. It is also clear that phosphorus played an important role, with Al, in the melt structure as can be seen from the absence or presence of crystals in the glasses of the different melts. This is possible because adding of phosphorus to the melt results in a depression of the T of the granitic melts' liquidus. Because of an interaction of phosphorus with Si networks and formation of complexes it also depolymerize aluminosilicate melts. The solubility of monazite was also tested in aqueous solutions under atmospheric conditions and low T (100-350 °C) to investigate low TIP alteration. Solutions ofCaCb +NaCl (1:1) chlorides were very reactive and dissolved the monazite completely, while solutions of CaCb were less reactive and only partly dissolved the monazite. These experiments demonstrate the concentrations required in hydrothermal solutions to destabilize monazite and explain textures found in natural rocks. Accessory minerals are useful discriminators between S-, I- and A-type granites and also their mineralized counterparts. Discrimination does depend on what accessory minerals are present and therefore apatite is the best mineral because it occurs in all the plutons. Petrography of these minerals is an indicator of primary or secondary processes. / AFRIKAANSE OPSOMMING: Die fokus van hierdie studie was om die mineraalchemie en paragenese van bykomstige minerale in S-, 1- en A-tipe graniete van die Kaapse Graniet Suite te vergelyk. Die doelwit van hierdie studie was om die verskille in chemie en petrografie van bykomstige minerale te gebruik as insig in die evolusie, herwinning en ontstaan van kontinentale kors soos geaffekteer deur die Kaapse Graniet Suite. Omdat SAE en spoorelemente hoe partisiekoeffisiente het vir bykomstige minerale speel hierdie minerale 'n belangrike rol om graniet evolusie te verklaar. Genoemde kenmerke van bykomstige minerale is ook gebruik om te onderskei tussen ongemineraliseerde en gemineraliseerde S-, 1- en A-tipe graniete in die suite. Die petrografie van die Kaapse Graniet Suite weerspieel die tweeledigheid van allanietmonasiet deurdat allaniet en titaniet in 1-tipe graniete en monasiet in S-tipe graniete voorkom. Monasiet word dus onstabiel in hoe Ca, 1-tipe, graniete. Apatiet kom in al drie tipes voor wat die mineraal se stabiliteit in verskeie geologiese omgewings weerspieel. Geronde kristalvorme , of reliekteksture, van apatiet en monasiet in S-tipe graniete weerspieel die sedimentere oorsprong van hierdie graniete. Konsentriese groei - en sektorale sonering kom algemeen voor in bykomstige minerale in ongemineraliseerde plutone. Sekondere veranderings rande (koronas) en onreelmatige sonering in gemineraliseerde plutone se bykomstige minerale is 'n aanduiding dat primere teksture gedeeltelik vemietig is deur sekondere prosesse. Katodeluminisensie en skandeerelektron mikroskopie ondersoeke het bewys dat SAE gehermobiliseer word na die koronas. Heelrotschemie en fisiese toestande van die magma word weerspieel in die mineraalchemie van bykomstige minerale. (Al~Fe) substitusie in titaniet word beheer deur P-T toestande en is, saam met Ca, Mn en Mg inhoud wat heelrotschemie weerspieel, goeie diskriminators in S- en 1-tipe graniete. LSAE en Sr inhoud in allaniet onderskei goed tussen plutone omdat hierdie elemente die heelrotschemie weerspieel. Omdat apatiet in al die plutone voorkom is dit die bruikbaarste mineraal om as diskriminant te gebruik. V anuit vorige werk is dit bekend dat die aluminium versadigings indeks die twee hoofsubstitusies: Ca+P~Si+SAE en Na+SAE~2Ca beheer, Fe en Mn inhoud in apatiet (0,1 pfu Mn en 0,05 pfu Fe is die afsnypunt tussen S- en 1-tipe graniete) weerspieel die oksidasietoestand van die magma en Sr, SAE en Mg weerspieel heelrotschemie. Saam kan hierdie elemente dus gebruik word as diskriminatore tussen die verskillende plutone. SAE patrone van allaniet en monasiet is sonder uitsondering verryk in die LSAE, terwyl apatiet en titaniet meestal "birdwing" profiele wys, maar kan ook verryk wees in LSAE of SSAE. Hierdie patrone word beinvloed deur kristallisasie van ander SAE-draende minerale, fraksionering van minerale uit die magma en die kristallisasie volgorde van die mineral e. Faseverwantskappe is eksperimenteel getoets tussen monasiet en allaniet in magmatiese toestande (780 °C en 1,8 kbar). Monasiet word onstabiel in 'n peralumineuse smelt (Aluminium versadigingsindeks >1) as waterig oplossings met konsentrasies van 0.7-7 g CaCh/1 0 cc H20 bygevoeg word. Cl-apatiet vorm as veranderingsproduk om die rande (koronas ). Allaniet is getoets in peralumineuse (Aluminium versadigingsindeks > 1) en metalumineuse smelte (Aluminium versadigingsindeks =1) met wisselende konsentrasies P20s (0.08 - 0.25 wt%). Allaniet het onstabiel geraak in peralumineuse smelte en hoe fosfor konsentrasies en het afgebreek na fases van LSAE+P± Ca, Al, K. Korona (kelifitiese) teksture is waargeneem. Hierdie eksperimente bewys dat fosfor, saam met Al, 'n belangrike rol speel in smeltstruktuur. Dit kan gesien word in die teenwoordig- of afwesigheid van kristalle in die glas. Dit is moontlik deurdat die byvoeging van fosfor 'n verlaging in die graniet likwidus temperatuur veroorsaak. Fosfor depolimeriseer ook aluminiumsilikaat smelte deur interaksie en kompleksvorming tussen fosfor en silika netwerke. Die oplosbaarheid van monasiet is ook getoets in waterige oplossings onder atmosferiese toestande en lae T (100-350 °C) om lae PIT veranderinge te ondersoek. 'n Versadigde oplossing van CaCh en NaCl (1:1) chloried het monasiet heeltemal opgelos terwyl 'n versadigde oplossing van CaCh monasiet net gedeeltelik opgelos het. Hierdie eksperimente dui op die konsentrasies nodig vir hidrotermale vloeistowwe waar bykomstige minerale onstabiel raak en verklaar teksture in natuurlike rotse. Bykomstige minerale kan dus gebruik word as diskriminators tussen ongemineraliseerde en gemineraliseerde plutone en ook tussen S-, I- en A-tipe graniete. Hulle kan egter net gebruik word as hulle teenwoordig is en daarom is apatiet die beste omdat dit in al die plutone aanwesig is. Petrografie is 'n aanduiding van magmatiese of sekondere prosesse.
139

Geodinamička analiza pomeranja Zemljine kore regionalnog karaktera / A geodynamical analysis of Earth's crust movements of regional character

Sušić Zoran 08 March 2014 (has links)
<p>Stanje Zemljine kore određeno je istovremenim i suprotstavljenim uticajem<br />endodinamičkih i egzodinamičkih procesa. Povr&scaron;inski slojevi omotača<br />Zemljine kore su u stalnom pokretu pod dejstvom uticaja, kao &scaron;to su<br />promena nivoa podzemnih voda, tektonske pojave, klizi&scaron;ta itd. Značajne<br />deformacije mogu se javiti kao posledica niza regionalnih i lokalnih<br />naponskih stanja, posebno u graničnim zonama litosfernih ploča, gde se<br />akumuliraju naponi i javljaju nelinearne innterseizmičke deformacije. U<br />disertaciji je prikazano istraživanje pomeranja Zemljine kore regionalnog<br />karaktera sa geodetskog aspekta, na osnovu ponovljenih opažanja metodom<br />satelitskog pozicioniranja, čime je dat doprinos multidisciplinarnom<br />razumevanju stanja Zemljine kore.</p> / <p>The state of the Earth&rsquo;s crust is determined by the simultaneous and opposed<br />influence of the endodynamic and exodynamic processes. The surface layers of<br />the Earth&rsquo;s crust envelope are in the state of permanent moving due to divers<br />influences, such as the level variation of underground waters, tectonic<br />phenomena, landslides, etc. Significant deformations can arise as a consequence<br />of a number of regional and local strain states, especially in the boundary zones<br />of lithosphere plates where strains are accumulated and non-linear interseismic<br />deformations appear. The subject of the thesis is a study of movements of the<br />Earth&rsquo;s crust of regional character from the aspect of geodesy, on the basis of<br />repeated observations by applying the satellite positioning method. In this way a<br />contribution is given to a multidisciplinary concept of the state of the Earth&rsquo;s crust.</p>
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Analyse isotopique des inclusions fluides des matériaux de la croûte terrestre : caractérisation des sources des fluides et reconstitutions paléoclimatiques / Isotopic compositions of fluid inclusions in the Earth crust : determination of fluid sources and palaeoclimatic reconstructions

Rigaudier, Thomas 25 January 2010 (has links)
Un des enjeux majeurs en Science de la Terre ces dernières décennies est de comprendre les interactions entre les différentes enveloppes terrestres. Le but poursuivi par ce travail est d’aborder quelques aspects de ces interactions du point de vue des cycles géochimiques des éléments volatils H2O et CO2 en se basant sur l’étude des inclusions fluides piégées dans des roches variées de la croûte terrestre, depuis sa surface jusqu’à l’interface croûte–manteau. La première partie de mon travail présente des travaux expérimentaux effectués sur de la halite. L’étude du fractionnement isotopique de l’oxygène et des cinétiques d’équilibration entre H2O et CO2 lors de l’évaporation de saumures a montré l’importance des corrections à effectuer sur les mesures isotopiques de l’oxygène pour des solutions de haute salinité. L’élaboration d’un protocole expérimental de précipitation de halite en milieu contrôlé a permis de mettre en évidence le potentiel des inclusions fluides pour les reconstitutions paléoclimatiques. La combinaison des données microthermométriques et des compositions isotopiques de l’hydrogène et de l’oxygène des inclusions aqueuses permet d’estimer les sources et la température de l’eau de formation de la halite ainsi que la vitesse du vent à l’interface eau-air pendant la croissance du cristal. Cette méthode a été ensuite appliquée aux dépôts de halite de Sicile datés du Messinien. La deuxième partie de mon travail est consacrée à l’identification des compositions chimiques et des sources des fluides circulant dans la croûte et à l’interface croûte-manteau à travers l’analyse des compositions isotopiques des inclusions fluides des granites et granulites. / One of the major challenges in Earth Sciences during the last decades has been to improve our knowledge of the interaction between the different components of the Earth System. Key aspects to improve the understanding of these processes are the acquisition of new data and the development of models to explain both mass and energy transfer between the deep and superficial components of the Earth system. The goal of this thesis is to study these transfers through the geochemical cycle of volatile elements trapped in fluid inclusions of various materials of the Earth crust. The first part of my work presents experimental study of halite. The study of oxygen isotope fractionation and equilibrium kinetics between H2O and CO2 during the evaporation of brines shows that corrections have to be made on the oxygen isotope measurements for high salinity solutions. The elaboration of an experimental protocol to form halite in controlled environment reveals the potential of fluid inclusions for palaeo climatic reconstructions. Combination of microthermometric data plus hydrogen and oxygen isotopic compositions of aqueous inclusions allows to estimate the sources and the temperature of the parental water of halite as well as the wind speed at the water-air interface during the crystal growth. This method was then applied to the Messinian halite deposits of Sicily. The second part of my work is dedicated to the identification of both the chemical compositions and the sources of fluids circulating in the crust and at the interface crustmantle through the analysis of isotopic compositions of fluid inclusions in granites and granulites.

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