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1
Ergene, Muge. "Petrography." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610105/index.pdf.
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Dorans, Hugh. "METEX: An expert system for metamorphic petrography." Thesis, Aston University, 1988. http://publications.aston.ac.uk/14370/.
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Classification of metamorphic rocks is normally carried out using a poorly defined, subjective classification scheme making this an area in which many undergraduate geologists experience difficulties. An expert system to assist in such classification is presented which is capable of classifying rocks and also giving further details about a particular rock type. A mixed knowledge representation is used with frame, semantic and production rule systems available. Classification in the domain requires that different facets of a rock be classified. To implement this, rocks are represented by 'context' frames with slots representing each facet. Slots are satisfied by calling a pre-defined ruleset to carry out the necessary inference. The inference is handled by an interpreter which uses a dependency graph representation for the propagation of evidence. Uncertainty is handled by the system using a combination of the MYCIN certainty factor system and the Dempster -Shafer range mechanism. This allows for positive and negative reasoning, with rules capable of representing necessity and sufficiency of evidence, whilst also allowing the implementation of an alpha-beta pruning algorithm to guide question selection during inference. The system also utilizes a semantic net type structure to allow the expert to encode simple relationships between terms enabling rules to be written with a sensible level of abstraction. Using frames to represent rock types where subclassification is possible allows the knowledge base to be built in a modular t'ashion with subclassirication frames only defined once the higher level of classification is functioning. Rulesets can similurly be added in modular fashio'n with the individual rules being essenrially declurative allowing for simple updating and maintenance. The knowledge base so far developed for metamorphic classification serves to demonstrate the performance of the interpreter design whilst also moving some way towards providing a useful assistant to the non-expert metamorphic petrologist. The system demonstrates the possibilities for a fully developed knowledge base to handle the classification of igneous, sedimentary and metamorphic rocks. The current knowledge base and interpreter have been evaluated by potential users and experts. The results of the evaluation show that the system performs to an acceptable level and should be of use as a tool for both undergraduates and rese:1rchers from outside the metamorphic petrogr:1phy field.
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Eakin, Paul Andrew. "The organic petrography and geochemistry of uraniferous hydrocarbons." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336031.
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Skopec, Robert A. "Geomechanical evaluation of a poorly consolidated sandstone with applications to horizontal drilling, borehole stability, reservoir compaction, and sand control." Thesis, University of Aberdeen, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274852.
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Decreasing strength with increasing effective compressive strength, referred to as "cap" behavior is often attributed to pore collapse and a reduction in pore throat apertures during early drawdown. Over-consolidation with only a slight increase in effective stress creates secondary fine particles that leads to formation damage and permeability decline. Grain crushing and the creation of a secondary fines population exacerbates pore blockage that results from mobilization of loosely attached kaolinite or other non-load bearing fine particles. Pore volume compressibility data indicate that compaction effects are significant and pose a potentially serious production problem during depletion. Pore volume lost during depletion is non-recoverable and will not "rebound." Re-injection of water will not re-establish the pore volume lost during compaction as a result of reservoir depletion. Compressibility and compaction trends in the Lower Captain Sandstone contradict several petroleum industry theories. Effective confining pressure and effective mean stress were higher under uniaxial strain boundary versus triaxial conditions and play a greater role in compaction than shear stresses. Captain pseudo shales exhibit strain-softening behavior and peak strengths are quite close to residual strengths. Captain pseudo shales clearly have residual load-bearing capacity and strain-softening promotes plasticicity. Use of standard core analysis methods to measure pore volume compressibility and fines migration potential are highly discouraged in unconsolidated as well as consolidated sandstones. Petrographic, mineralogical, and routine petrophysical analyses are essential in the interpretation of rock mechanics data.
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Kenyon-Roberts, Stephen M. "The petrography and distribution of some calcite sea hardgrounds." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318580.
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Hird, Kevin. "Petrography and geochemistry of some Carboniferous and Precambrian dolomites." Thesis, Durham University, 1985. http://etheses.dur.ac.uk/1674/.
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Rothschild, Alison. "Ground ice petrography, Sand Hills Moraine, southern Banks Island, N.W.T." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5504.
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Grimmer, Stephen C. "Geochemistry and petrography of alkali volcanics from the Oslo Palaeorift Norway." Thesis, Keele University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293779.
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Röser, Georg. "Petrography, physical properties, and geotechnical behavior ofmodern sediments, Southern Chile Trench." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-42037.
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Ali, Abdulmajid Muhammad. "Integrated Petrography, Geochemistry and Petrophysical Characteristics of Miri Formation, Sarawak, Malaysia." Thesis, Curtin University, 2022. http://hdl.handle.net/20.500.11937/87929.
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An integrated approach (Petrography, Mineralogy, Geochemistry, and Petrophysics) was used to elucidate the paleoweathering, provenance and tectonic setting of the Miri Formation and its reservoir potential. The research suggests that the sediments of the Miri Formation were mainly recycled from the Rajang Group, undergone moderate to intense weathering and deposited in an evolving active to passive margin setting. The reservoir quality of the Miri Formation has been assessed and their controlling factors are addressed.
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Schuetz, Corinna. "Stratigraphy, petrography and geochemistry of the Kaiwhata Limestone, Pahaoa, New Zealand." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/232515/1/Corinna_Schuetz_Thesis.pdf.
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This thesis examined the stratigraphy, petrography, and geochemistry of the Paleocene to Eocene pelagic sedimentary deposits in Pahaoa, Wairarapa, North Island, New Zealand. Laboratory and statistical techniques are employed to assess the change in depositional environment prior to the onset of subduction. The results provide insights into the modes of deposition, stratigraphic evolution of the passive margin sequence and tectonic setting of the receiving basin before subduction initiation of the Hikurangi margin.
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Browne, Joanna Rae. "Sandstone provenance and diagenesis of arc-related basins : James Ross Island and Alexander Island, Antarctica." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307271.
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Perry, Martin John. "A study of the factors that influence the polishing characteristics of gritstone aggregates." Thesis, University of Ulster, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298631.
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Marconi, Manuela. "The rise and fall of a Jurassic bank-basin system : Umbro-Marchean Apennines, Italy." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319159.
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Loughlin, Susan C. "The evolution of the Eyjafjöll volcanic system, southern Iceland." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/1456/.
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Prater, Tanita. "Comparison of rock-type-derived reservoir properties with estimates from standard petrography /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09S.B/09s.bp912.pdf.
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Wickens, Leretta. "Geochemistry and petrography of speleothems from Turkey and Iran : palaeoclimate and diagenesis." Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/47931/.
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Speleothems contain key archives of palaeoclimatic information, which can be interpreted through multiple geochemical and petrographic proxies, and precisely dated by Uranium Series dating. As U/Th dating is only viable for samples up to approximately 700 kyr of age, U/Pb dating must be used to date older samples. In this study, U/Pb methods were used to date an aragonite layer in a speleothem from Iran, following the use of autoradiography to select samples with appropriately high uranium. Aragonite is metastable at earth surface conditions, and is therefore prone to recrystallisation as calcite if it comes into contact with a fluid that is undersaturated with respect to aragonite. This process affected two speleothems from Dim Cave, SW Turkey, and one speleothem from Torang Cave, Iran. The older Dim Cave stalagmite, which precipitated during MIS 5e, was not identified as a recrystallised stalagmite at first, as the mineralogy of the growth axis appeared to show a change in primary mineral rather than recrystallisation. Despite the fact that recrystallisation had occurred, it was possible to create an age model, as the system had not opened to a great degree. The persistence of an aragonite layer in this speleothem, as well as several other geochemical proxies, indicates that an arid phase occurred during early MIS 5e in SW Turkey. The second recrystallised speleothem from Dim Cave provides useful insights into the geochemical and petrographic character of recrystallised speleothems. The recrystallised speleothem from Torang Cave produced a record of climatic instability in southern Iran during MIS period 9- 7, although the age model was not precise enough to draw precise conclusions. A small aragonitic Holocene growth from Dim Cave grew during a time which corresponds to an early Holocene pluvial period that affected the entire eastern Mediterranean Basin, coinciding with the deposition of Sapropel 1.
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Ownby, Mary. "Canaanite jars from Memphis as evidence for trade and political relationships in the Middle Bronze Age." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/226319.
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Trade between two regions often necessitates that the respective parties are political entities. This was indeed the case for trade between Egypt and the Levant during the Middle Bronze Age (ca. 2000-1550 BC, MBA) and Late Bronze Age (ca. 1550-1200 BC, LBA). Scientific analyses of Canaanite jars, transport vessels, from the site of Memphis, Egypt provided an ideal proxy for examining the relationship between trade and politics. During the MBA, Levantine peoples were present at the site of Tell el-Dabca in the eastern Nile Delta. However, archaeologically there is little evidence for contact between these peoples and the Egyptians at Memphis. Results of comparison of MBA Canaanite jars from both sites suggest the political situation fostered trade with the Levant and limited interaction with the Egyptians. During the LBA, Egyptian kings controlled territory in the Levant. A comparison of MBA and LBA Canaanite jars from Memphis revealed that the political changes in some cases affected the trade partners but not in others. Further, the production of the jars appeared to have altered in some regions. These results suggest that the affect of political situations on trade can vary, from only minor changes, to the complete exclusion of trade partners and the introduction of new trade contacts. However, the influence of lucrative trade networks on political developments was also illustrated. The utility of provenance studies of ceramics for understanding the complex relationship between trade and politics was confirmed.
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Ruiz, Larissa Marques Barbosa de Araújo [UNESP]. "Caracterização petrológica, geoquímica e geocronológica (U/Pb e Ar/Ar) do maciço sararé Nova Lacerda-MT." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/92938.
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ruiz_lmba_me_rcla.pdf: 5013284 bytes, checksum: 8e0476480ddec9386170f64c5424e861 (MD5)O Maciço Sararé, pertencente ao Terreno Santa Helena no Cráton Amazônico, situa-se a cerca de 60 Km a norte da cidade de Pontes e Lacerda, sudoeste de Mato Grosso, apresentando o contato leste e nordeste recoberto pelas rochas sedimentares da Bacia Cretácica Parecis. Encontra-se intrusivo em rochas metamórficas do Complexo Vulcano-sedimentar Pontes e Lacerda em gnaisses e migmatitos ortoderivados (Complexo Metamórfico Alto Guaporé, Maciço Sapé e Anhanguera) de idades mesoproterozóicas. Compreende um corpo de 80 Km2, constituído por três fácies petrográficas graníticas principais, cujos contatos são transicionais. As rochas apresentam composição monzogranítica, são inequigranulares a localmente porfiríticas, granulação dominantemente média, constituídas por microclínio, quartzo, oligoclásio límpido ou saussuritizado , abundantes placas de muscovita (primárias ou secundárias), rara biotita cloritizada e fluorita metassomática, além de titanita e minerais opacos. A Fácies Biotita Monzogranito é dada por rochas equigranulares de granulação média-fina, cor avermelhada, leucocráticas, isotrópicas que ocorrem na porção sul do corpo. A Fácies Muscovita Monzogranito é representada por rochas inequigranulares, granulação média-grossa, cor rósea, hololeucocráticas e isotrópicas, que ocorrem na porção norte e central da intrusão. A ocorrência principal da Fácies Monzogranito aflora no extremo norte da área de forma isolada, como um plug granítico e dentro do maciço como diques aplíticos tardios. São constituídas por rochas leucocráticas, róseas, isotrópicas, ineqüigranulares a porfiríticas de granulação fina a média. A tectônica regional com direção NW-SE controla e define a forma alongada do Maciço Sararé acompanhando o trend regional de suas encaixantes. Tardiamente, uma tectônica rúptil manifestada através de fraturas...
The Sararé Granite belongs to the Santa Helena Terrain within the Amazonian Craton and is located about 60 km north of the city of Pontes and Lacerda, of southwest Mato Grosso. The east and northeast contacts of the body are marked by the sedimentary rocks of the Cretaceous Parecis Basin, while its remaining intrusive contacts are the metamorphic rocks of the Pontes and Lacerda volcano-sedimentary complex and orthogneisses and migmatites (Alto Guaporé Metamorphic Complex, Sapé and Anhangüera Massifs) of Mesoproterozoic age. The areal extent of the instrusion is approximately 80 km2 and is constituted by three major monzogranitic petrographic facies (biotite monzogranite, muscovite monzogranite and monzogranite) whose contacts are transitional. These rocks present monzogranitic composition, are unequigranular to locally porphyritic with medium grain size, constituted by microcline, quartz, oligoclase, abundant muscovite, rare cloritized biotite and metassomatic fluorite plus titanite and opaque minerals. Biotite monzogranitic facies is represented by equigranular of medium to small grain size, red-colored, leucocratic and isotropic rocks, that crop out in the southern portion of the body. The facies of muscovite monzogranite is represented by medium to coarse inequigranular textures, rose-colored, hololeucocratic and isotropic rocks that occur in the north and central portion of the intrusion. Monzogranite facies crops out in its main occurrence in the north end of the area and are interpreted as late-stage granitic plugs, constituted by inequigranular of medium to small grain size to porphyritic leucocratic rosy isotropic rocks. Their occurrence is characterized as localized intrusive bodies, including late aplite dikes, into the other ...(Complete abstract click electronic access below)
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Miller, James Fisher. "Granite petrogenesis in the Cordillera Real, Bolivia and crustal evolution in the Central Andes." Thesis, Open University, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292357.
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Vallini, Daniela Alessandra. "The formation of authigenic xenotime in Proterozoic sedimentary basins : petrography, age and geochemistry." University of Western Australia. Geology and Geophysics Discipline Group, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0070.
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[Truncated abstract] The realization in 1999 that the authigenic phosphate, xenotime, could be used in geochronological studies to place age constraints on burial events that affected sedimentary basins has opened numerous opportunities for establishing timeframes for sedimentary basin analysis. Since then, the mineral has been used to place new and novel age constraints on diagenesis, metamorphism, and hydrothermal alteration and mineralization events. Whilst these studies were successful, they identified many complexities in xenotime growth and were restricted to specific areas or single basins: they do not convey, demonstrate or explore the immense variety of geological applications in which xenotime may provide unique geochronological constraints. This thesis explores the nature of authigenic xenotime, utilizing studies in three different Proterozoic sedimentary basins: two in Australia, southwestern Australia and the Northern Territory, and the third in the United States of America. The thesis includes a number of discrete studies demonstrating different aspects of xenotime growth, elucidated from detailed petrography, geochronology and geochemistry of authigenic xenotime. An integrated textural, geochemical and geochronological study of authigenic xenotime from the Mt Barren Group, SW Australia, establishes an absolute timescale on some of the many processes involved during the diagenesis of siliciclastic units. ... positions and trends and broadly confirm the chemical discrimination criteria established for an Archaean basin. However, the Proterozoic data are shifted to lower Gd-Dy values and extend beyond the original field outlines, causing more overlap between fields intended to discriminate xenotimes of different origin. The plots were revised to encompass the new data. This study has significantly extended our knowledge of the nature of authigenic xenotime. It was found that xenotime may form in (meta)sediments in response to a large number of post-depositional processes, including early- and latediagenesis, (multiple) basinal hydrothermal events and low-grade metamorphism. A combination of detailed petrography and in situ geochronology provides the best avenue to decipher complex growth histories in xenotime. With further development, it is likely that xenotime geochemistry will also prove diagnostic of origin and can be incorporated into the interpretation of age data. The number of potential applications for xenotime geochronology has been expanded by this study.
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Dean, A. A. "Analysis and correlation of igneous clast geochemistry and petrography from four Mesozoic conglomerates." Thesis, University of Canterbury. Geology, 1993. http://hdl.handle.net/10092/9341.
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The Torlesse terrane encompasses three-quarters of the emergent New Zealand micro-continent and much speculation has been made as to the likely source for the detritus of which it is composed. This research concentrates on an examination of the igneous (plutonic and volcanic) clasts from three Torlesse conglomerates, one from the Rakaia terrane of Triassic age, and two from the Pahau terrane, of Early Cretaceous age, to obtain a better understanding of the characteristics of this source terrane. The Early Cretaceous Ethelton conglomerate comprises predominantly metaluminous I-type and weakly peraluminous evolved I-type granitoids that relate mineralogically and geochemically to the rhyolitic and dacitic volcanic clasts present and are thought to represent one cogenetic suite derived by partial melting of a common igneous source.
The Mount Saul conglomerate contains a predominance of volcanic clasts and a variety of granitoid types. Some volcanic clasts relate to the I-type, and evolved I-type granitoids present. A-type peralkaline to weakly peraluminous volcanic clasts geochemically display a subduction related signature, that reflects source characteristics. A-type magmatism indicates an event unassociated with represented intrusives, either related to anorogenic magmatism or to a change to extensional tectonism.
The predominant granodiorite character and low K content of Lake Hill conglomerate S type granitoid clasts contrasts with that of the other conglomerates. The dacitic and rhyolitic volcanic clasts examined from Lake Hill exhibit distinctive minerals indicative of I-types and relate to the evolved I-type granitoid clasts also present.
The middle Cretaceous conglomerate located on Pitt Island, Chatham Islands is also examined to provide a comparison to the Torlesse conglomerates and an insight into source characteristics prior to continental separation between New Zealand and West Antarctica.
The Chatham Islands conglomerate contains a variety of granitoid and volcanic types that are petrographically and geochemically comparable with the Torlesse conglomerates. The granitoid clasts are predominantly leucosyenogranites and leucomonzogranites. The volcanic clasts are rhyolites and dacites. Geochemically I-type, S-type and highly evolved/A-types are identified.
The clasts from all four conglomerates examined exhibit trace element characteristics indicative of subduction-related magmatism. The granite type and highly felsic nature of most clasts indicates intrusion and extrusion occurred along an active continental margin that had attained full crustal thickness. The mineralogy and geochemistry of conglomerate clasts compares favourably with numerous volcano-plutonic continental provinces around the Pacific margin that are believed to represent the former Gondwana margin.
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Patton, David James Stanley. "The petrography and petrochemistry of the Tertiary basic hypabyssal intrusions of northeast Ireland." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356968.
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Kuscu, Gonca Gencalioglu. "Petrography and geochemistry of silicic volcanics in the Akdagmadeni region, central Anatolia, Turkey." Thesis, Keele University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263122.
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Turner, Tom. "Petrography, alteration and structure of the Bronäs Zn-Pb-Ag deposits, Bergslagen, Sweden." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-78822.
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This report aims to characterize the alteration styles and mineralization of the Zn-Pb-Ag Bronäs deposit, in the Sala area of the Bergslagen mining district, Sweden. It presents data collected through 237m of lithological logging and subsequent lithogeochemical data, which, coupled with thin section and SEM analysis has led to the first geological descriptions of the rocks in the deposit. The results are presented in the report through logs and a cross-section interpreted from these logs. The Bronäs deposit, mined between 1945 and 1962, is a satellite deposit to the well-known Sala mine, and similarly to the Sala deposit, it is hosted within an extensive marble unit interbedded with layers of felsic volcaniclastic material. The rocks in the area have first been dolomitized and then undergone regional metamorphism to greenschist facies at 1.87 Ga. There is a large granitic batholith to the south and east of the deposit, and a thin porphyritic intrusion with a complex geometry closely spatially associated with the mineralization. The marble unit is the host unit for the mineralization and is the most commonly occurring rock type in the study area. It is commonly quite impure and variably skarn altered throughout, with common gangue minerals including serpentine, chlorite, tremolite, diopside and phlogopite. The mineralized sections of the marble are spatially related to the skarn-rich areas of marble, and common sulphides include pyrite, galena and sphalerite. The interbedded volcaniclastic beds have a rhyolitic composition, and also contain Mg-silicates such as chlorite, tremolite and phlogopite, giving them a green colour too. The contacts between volcaniclastic and marble beds is often marked by contact skarns. The porphyritic intrusion has a granodioritic composition. It exhibits chilled margins, and the contact between it and the marble is often marked by increased skarn alteration in the marble. The feldspar crystals in the unit are zoned, with a white outer rim and a green to yellow sericitic core. The cross section shows that all the units are steeply dipping to the south-west, with steeply dipping stratabound lenses of mineralization in the marble, sub-parallel to the volcaniclastic beds in the north east. The south-western part of the section is thick uninterrupted marble. Lithogeochemical results have been divided into two groups – a distal group within this thick marble, and a proximal group close to the mineralization and volcaniclastic beds. The proximal zone is enriched in SiO2 and Al2O3 and depleted in FeO, MnO and MgO relative to the distal zone. The Mn and Mg values are enriched when compared to regional levels however. The proximal zone also contains more Pb, Zn, Ag, As and Sb than the distal zone, but contains lower amounts of Au and Cu than the distal zone. There is one hotspot in the distal zone which contains high concentrations of Pb, Zn, Ag, Au, Cu and Sb. The chemical signature is similar to the mined ore at Sala. The common occurrence of Fe, Mg and Mn-bearing skarn minerals near the mineralization suggests these elements should be higher in the mineralized zone, but skarn minerals are common throughout the study area, and the high levels of Si and Al in the mineralization zone could be diluting the other oxides. The lenses of mineralization are closely spatially related to the porphyritic intrusion however the intrusion is relatively minor in terms of size and is younger and unaltered. It could have followed an existing fault which was related to the mineralization though. Various examples of sulphide replacement and retrograde alteration can be seen, such as galena replacing amphiboles and barite. The similarity in mineralogy between regional metamorphic calc-silicates and ore-related skarn minerals makes it hard to differentiate between the two, however the presence of high temperature clinopyroxene indicates the deposit is likely a prograde metasomatic skarn deposit. This is backed up by a similar calc-silicate assemblage, mineralization style and replacement textures to those associated with skarn deposits. It is also spatially related to magmatism with mineralization occurring along lithological contacts.
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Sanders, Margaret McPherson. "GEOCHEMISTRYAND PETROGRAPHY OF THERMALLY METAMORPHOSED ANTARCTIC COAL: IMPLICATIONS FOR 13C -DEPLETED METHANE RELEASE." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/821.
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Large δ13C excursions present at the Permian-Triassic boundary are thought to indicate a considerable release of isotopically light carbon into the atmosphere (Retallack and Jahren, 2008). The largest of these excursions (-22.2 ‰) was measured in organic matter from Antarctica (Retallack and Jahren, 2008). Antarctic coals are known to be heavily intruded by Jurassic dikes and sills, and the δ13C values of the organic matter may have been influenced by later thermal alteration. In order to evaluate the influence of rank and maceral content on isotopic composition, a total of 335 samples described as Permian-age "coal" were obtained primarily from the United States Polar Rock Repository. Most of the organic matter from Permian coal seams in Antarctica has been extensively altered after burial by localized high heat flow and, in some cases, contact metamorphism associated with dikes and sills; this thermal alteration has likely changed the δ13C values of the organic matter. The rank of the samples prior to intrusion is estimated to be medium to high volatile bituminous. The majority of the samples analyzed (96%) have been altered to above low volatile bituminous rank based on vitrinite reflectance, most (83%) are semi- to meta-anthracites, and a few have been altered to anisotropic cokes. The samples do not follow the typical burial maturation geochemical track, as they are higher in volatile matter (%, daf) and O (%, dmmf), and lower in H (%, dmmf) than coals of the same rank that have undergone normal burial maturation. Carbon stable isotopic data indicate a weak correlation with coal rank as well as with the amount of pyrolitic carbon. Although the isotopically lightest samples measured in this study are located within what is interpreted to be the Permian-Triassic boundary, the effects of thermal alteration of organic matter on δ13C values must be considered in any interpretation of Permian-Triassic atmospheric conditions.
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RESENTINI, ALBERTO. "Quantitative provenance analysis of modern sands: bulk petrography, heavy minerals apatite fission tracks." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/19000.
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Sediment petrography and heavy mineral analysis represent two key techniques to decipher the pieces of information stored in the sedimentary record, shedding light on source rocks compositon, weathering conditions and paleodrainages. Traditionally, even though orogenic detritus has always received large attention, orogenic provenance has been recognized as “composite”, thus preventing clear classification. Notwithstanding the composite nature of collision orogens, the detrital fingerprints of neometamorphic axial
belts, largely experiencing strong exhumation and erosion, can be regarded as the diagnostic signature of orogenic detritus. We thus decided to focus our attention on the analysis of modern river sands from the Alpine belt, getting full quantitative information both on bulk compositions and heavy mineral assemblages.
Within the Austroalpine Cretaceous and Penninic Eocene axial belts of the Alps, we ideally distinguish three structural levels, each characterized by diagnostic detrital fingerprints.
The shallow level chiefly consists of offscraped remnant-ocean turbidites and
unmetamorphosed continental-margin sediments, and mostly produces lithic to
quartzolithic sedimentaclastic sands yielding very-poor heavy-mineral suites including ultrastable minerals. The intermediate level includes low-grade metasediments and
polymetamorphic basements, and sheds quartzolithic to feldspatholithoquartzose
metamorphiclastic sands yielding moderately-rich epidote-amphibole suites with chloritoid or garnet. The deep level contains eclogitic remnants of continent-ocean transitions, and
supplies feldspatholithoquartzose/feldspathoquartzose high-rank metamorphiclastic to
lithic ultramaficlastic sands yielding rich to extremely-rich suites dominated by garnet,
hornblende, or epidote depending on protoliths (continental vs. oceanic) and
pressure/temperature paths during exhumation. Although widely overprinted under
greenschist-facies or amphibolite-facies conditions, occurrence of ultradense eclogite in source areas is readily revealed by the Heavy Mineral Concentration (HMC) index, which mirrors the average density of source rocks in the absence of hydraulic-sorting effects.
Rather than the pressure peak reached at depth, the Metamorphic Index (MI) and
Hornblende Colour Index (HCI) reflect peak temperatures reached at later stages, when
subduction is throttled by arrival of thicker continental crust and geothermal gradients increase, as documented in detritus derived from the Tauern window and Lepontine dome.
Experience gained from modern sediments, and appropriate statistical techniques provides fundamental help to decrypt the information stored in the sedimentary record, and thus to identify and reconstruct subduction events of the past.
Besides the fundamental contribution that modern sediment analysis can bring in
understanding ancient sandstone successions, it can also give insights on short-term
erosion distribution over wide areas and readily detect potential area of focused erosion.
We tested a new quantitative approach based on the integration of compositional data
and detrital apatite fission-tracks in two valleys of the western Alps (Arc and Dora Baltea basins).
Samples for bulk-petrography and fission-track analysis were collected at different closure sections along the trunk, in order to investigate how the detrital signal evolves when detritus from different sub-basins is progressively added to the system. Fission-track analysis is a powerful integration tool to quantify sediments mixing if source areas experienced contrasting exhumation paths. Fission-track grain-age distributions provide not only information on long-term exhumation patterns, based on the age of the peaks,
but also provide first-order constraints on short-term erosion rates by comparison between the size of the peaks and the size of potential source areas. In the Dora Baltea catchment, the apatite load derives from two major fault-bounded blocks, the Western one yielding 43% of the total amount of apatite, and the Eastern one yielding the remaining 57%. In the Arc catchment, contribution is 29% from the Eastern Block, 14% from the Houiller-Subbriançonnais units and 57% from the Belledonne-Dauphinois units. We assessed apatite fertility in source-rocks by measuring apatite content in processed sediments, after checking for anomalous hydraulic concentrations by geochemical analyses. The lack of
compositional anomalies for elements between Y and Cr, largely hosted in ultradense minerals, grants that source-rocks distribution in the basin is faithfully reflected by detrital assemblages.
Results demonstrate that erosional processes were focused in different areas of the
Western Alps at long-term and short-term timescales, and are now concentrated in the
External Massifs. No clear relationship between erosion and climate or relief is observed in this sector of the belt, where endogenic forces may represent the main controlling factor on both long-term and short-term erosion rates.
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Fratton, Christopher Mark. "Petrography and structural petrology of the Aldermac Syenite Igneous Complex and its related dikes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0012/MQ40762.pdf.
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Jagodziński, Robert. "Petrography and geochemistry of surface sediments from Sunda and Vietnamese shelves (South China Sea) /." Poznań : Wydawn. Naukowe, 2005. http://www.loc.gov/catdir/toc/fy0801/2007422802.html.
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Prévôt, Liliane. "Geochemistry, petrography, genesis of Cretaceous-Eocene phosphorites : the Ganntour deposit, Morocco : a type example /." Paris : Société géologique de France, 1990. http://catalogue.bnf.fr/ark:/12148/cb35430903w.
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Texte traduit de: Th. Etat--Sci. nat.--Strasbourg 1, 1988. Titre de soutenance : Géochimie et pétrographie de la formation à phosphate des Ganntour, Maroc ; utilisation pour une explication de la genèse des phosphorites crétacé-éocènes.Résumé en français. Bibliogr. p. 210-218.
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Whittle, Caroline Kay. "Analytical transmission electron microscopy of authigenic chlorites." Thesis, University of Sheffield, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324284.
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SILVA, Mickey Anderson Paixão da. "Influência das características morfológicas de britas graníticas e gnaíssicas na resistência à compressão do concreto." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18425.
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Em virtude dos agregados constituírem os recursos minerais mais acessíveis e também serem responsáveis por uma enorme parcela do material consumido na construção civil, faz-se necessário um estudo mais aprofundado a respeito da utilização e aplicação dessa matéria prima. O objetivo principal é qualificar a relação entre os resultados de resistências à compressão do concreto, obtidos por meio de testes feitos em corpos-de-prova moldados com diferentes tipos de brita, de modo a identificar aquela que proporciona uma maior resistência no mesmo, quando submetido aos esforços uniaxiais de compressão. Para isso foram escolhidas amostras de rochas, sendo três granitos e três gnaisses para análise da qualidade do concreto produzido a partir das respectivas britas. As britas foram analisadas macroscopicamente e todas as amostras foram submetidas às mesmas etapas de britagem, e posteriormente o material resultante dessa etapa passou pelo peneirador mecânico. Através desse processo, avaliou-se individualmente o índice de forma, o módulo de finura e o percentual dos minerais com clivagem dos devidos tipos de rochas afim de entender melhor o motivo dos posteriores resultados do comportamento do concreto com relação à trabalhabilidade e resistência a compressão uniaxial para cada um dos tipos de brita. A escolha do tipo de cimento torna-se muito relevante para esta análise. Faz-se necessário a escolha de um cimento que dê margem para que o tipo de brita seja a variável mais importante e decisiva no processo de resistência. Observa-se também que o índice de forma está relacionado ao percentual de minerais presentes na rocha que apresentam planos de clivagem. O valor do índice de forma está diretamente relacionado aos teores de minerais com um ou mais planos de clivagem contidos em cada amostra. Por fim, ficou constatado que o concreto que apresentou a maior resistência à compressão foi confeccionado por agregados com os menores módulos de finura; já os agregados com o maior módulo de finura resultaram num dos concretos menos resistentes.
Because the aggregate constitute the most accessible mineral resources and also account for a huge portion of the consumed in construction material, it is necessary to further study regarding the use and application of this raw material. The main goal is to qualify the relationship between the results of resistance to the concrete compressive obtained by means of tests made on specimens test pieces molded with different types of gravel, in order to identify one that provides greater strength in that when subjected to uniaxial compression efforts. For this rock samples were selected: three and three granite gneiss for analysis of the quality of concrete produced from the respective gravel. The gravel was analyzed macroscopically and all samples were subjected to the same steps of crushing, and then the resulting material has passed this stage by mechanical sieving. Through this process, we assessed individually the form of an index, the fineness modulus and percentage of minerals with cleavage of proper rock types in order to better understand the reason for the subsequent behavior of concrete results regarding the workability and compressive strength uniaxial for each type of grit. The choice of the type of cement becomes very relevant to this analysis. It is necessary to choose a cement margin so that the type of grit is most important and crucial variable in resistance process. It is also observed that the form of an index is related to the percentage of minerals present in the rock show cleavage planes. The value of the medium index is directly related to mineral contents in one or more cleavage planes contained in each sample. Finally, it was found that the concrete with the highest compressive strength was made by households with the lowest fineness modules; since aggregates with higher fineness modulus resulted in the least resistant concrete.
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Mattos, Irani Clezar. "Geologia, petrografia, geoquímica, comportamento físico-mecânico e alterabilidade das rochas ornamentais do stock granítico Serra do Barriga, Sobral (CE) /." Rio Claro : [s.n.], 2005. http://hdl.handle.net/11449/103004.
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Resumo: O stock granítico Serra do Barriga é pós-tectônico, polintrusivo, com 522,2l7.6Ma, apresenta tipos faciológicos de sienogranitos e monzogranitos inequigranulares a megaporfiríticos diferenciados pela coloração, aspectos composicionais e texturais. Investigou-se os tipos ornamentais Rosa Iracema, Rosa Olinda, Branco Savana e Branco Cristal Quartzo. Geoquimicamente são rochas peraluminosas, cálcio-alcalinas alto potássio formadas por magmas evoluídos, em ambiente orogênico pós-colisional. Transformações pós-magmáticas indicam origem por fracionamento de mesmo magma parental, acrescidos por pulso mais máfico (Rosa Olinda). A correlação entre índices físicos, resistência física e mecânica ocorre em função dos aspectos petrográficos. Os granitos rosas apresentam melhor desempenho para fachadas. Os parâmetros tecnológicos apresentados são superiores ou próximos aos valores limítrofes estabelecidos, qualificandoos como detentores de boa qualidade. No ataque químico os granitos reagem de forma semelhante, com variações cromáticas e alterações minerais sutis, indicando serem resistentes. Entretanto granitos rosas apresentam maior perda de brilho e corrosão mineral em contato com ácidos cítrico e clorídrico, reagentes mais destrutivos. Embora resistentes, deve-se evitar exposições prolongadas dos granitos estudados à substâncias contendo ácidos. Estes granitos são adequados para fins ornamentais, sendo os rosas (Iracema e Olinda) altamente resistentes, eficientes para aplicação em pisos e fachadas de ambientes interiores e exteriores, com cuidados na manutenção.Abstract: The polyintrusive Serra do Barriga granitic stock is post-tectonic, with a 522.2 l 7.6 Ma age. It presents inequigranular to megaporphyritic syenogranitic and monzogranitic faciological types differing by collor, composition, and textural aspects. In this research we investigated the following ornamental types: Rosa Iracema, Rosa Olinda, Branco Savana, and Branco Cristal Quartzo. Geochemically these are peraluminous, high-potassium calcium-alkaline rocks formed from highly evolved magmas in a post-collisional orogenic environment. Late-magmatic transformations indicate an origin by fractioning of a unique parental magma, added by a mafic pulse (Rosa Olinda). The correlation between the physical indices and the physical and mechanic resistance were done as a function of the petrographycal analyses. The technological parameters obtained are higher or close to the bordering values, which characterises these rocks as good quality ones. The granites react to the chemical attack by slight both chromatic variations and mineral alterations, indicating to be resistant rocks. The rose colored granites, however, show a greater alteration when in contact with the more destructive citric and chloridric acids. Although resistant, one sends regards to prevent expositions to acid-bearing substances. The granites of the Serra do Barriga stock are adequate for ornamental use, being the Rosa Iracema and Rosa Olinda types highly efficient for both floor pavement and wall covering, with care in the maintenance.
Orientador: Antonio Carlos Artur
Coorientador: José de Araújo Nogueira Neto
Banca: Tamar Milca Bortolozzo Galembeck
Banca: Antenor Braga Paraguassú
Banca: Eleno de Paula Rodrigues
Banca: Maria de Fátima Bessa Torquato
Doutor
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Giles, Andrew. "The lithology and petrography of the 39 NH51 South East Decline, Roxby Downs, South Australia /." Title page, contents and abstract only, 1986. http://web4.library.adelaide.edu.au/theses/09SB/09sbg4715.pdf.
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Venturi, Chantal Margot. "Stratigraphy, petrography and major element mineral chemistry of the Wadi Qutabah Layered Mafic Complex, Yemen." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44059.
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Little is known about the recently discovered Wadi Qutabah Layered Mafic Intrusion in Yemen. It possesses significant potential for the discovery of economic platinum-group element (PGE) and Ni-Cu-Co mineralization, and is believed to be part of the larger Suwar-Wadi Qutabah Layered Mafic Complex. The intrusion was recently dated as being Neoproterozoic in age (~638.5Ma). The current estimated size of the complex is ~250km². Mineralization has been identified in the Suwar area which lies ~30km to the southeast of Wadi Qutabah. Anomalous platinum mineralization was identified in stream sediment samples that run off of the Wadi Qutabah intrusion. Little is known about the stratigraphy, mineralization, layering and geochemistry of the rocks from Wadi Qutabah. Drill cores from 14 drill holes were used to study the stratigraphy, petrography and mineral chemistry of the Wadi Qutabah intrusion. Methods employed were drill core logging, petrographic analysis and mineral grain analyses using the Scanning Electron Microscope (SEM/EDS). Rocks from the Wadi Qutabah intrusion are medium to coarse-grained cumulate norites and gabbros with minor anorthosite, pyroxenite, and localized massive sulphide layers. Correlation of the layering was accomplished in a broad scale as a result of modal and phase layering, stratigraphic position and textural variations. Lithological unit codes were created for the purposes of correlation and identification for this study. Each of the units/layers is host to unique textures, mineralogy and stratigraphic position. They correlate across stratigraphy from drill hole to drill hole, but lateral changes in alteration and thickness are common. Significant changes in chemistry occur at the top of unit 5a (augite norite) which occurs in the middle of the section. The reversal in chemistry towards more primitive compositions up stratigraphy, are the result of injection of new hot primitive magma. Comparison of the mineralogy and chemistry of the Wadi Qutabah intrusion with other layered intrusions indicates that the complex is >2km in thickness and that there are prospective areas for PGE mineral exploration. Discriminant analysis of augite composition suggests that the magmas are derived from within plate tholeiites. A composite stratigraphic column yields a section ~500m thick in the area.
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Johnston, Michelle N. "A Petrographic Characterization of the Leatherwood Coal Bed in Eastern Kentucky." UKnowledge, 2014. http://uknowledge.uky.edu/ees_etds/18.
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The Eastern Kentucky Coal Field is located in the central portion of the Appalachian Basin. The Pennsylvanian Breathitt Formation in this region is characterized by numerous sequences of bituminous coal-bearing sedimentary rocks. These coals have distinct maceral compositions due to variations in depositional environments. Coal characterization is an important method for determining conditions that influenced peat accumulation and overall depositional settings of mires.
This study focuses on the characterization of the maceral composition of the Middle Pennsylvanian-age Leatherwood coal bed. It utilizes petrographical, palynological, and geochemical analyses to describe specific depositional environments and associated peat accumulation conditions.
Petrographic analyses indicate that these coals have relatively high liptinite and varying inertinite content, along with trace amounts of mineral matter. Vitrinite, mainly in the form of collotelinite, is the most dominant maceral group. Geochemical data reveal low ash and sulfur content. Ancillary palynological data shows the palynomorph assemblage to be dominated by tree fern and large lycopsid tree spores, with lesser amounts of small lycopsid tree, small fern, and cordaites and calamites spores. The petrographic, geochemical and palynological data indicate that both domed, ombrotrophic, and planar, rheotrophic mire conditions, with limited local detrital influx, contributed to the formation of the Leatherwood coal.
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Ruiz, Larissa Marques Barbosa de Araújo. "Caracterização petrológica, geoquímica e geocronológica (U/Pb e Ar/Ar) do maciço sararé Nova Lacerda-MT /." Rio Claro : [s.n.], 2003. http://hdl.handle.net/11449/92938.
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Resumo: O Maciço Sararé, pertencente ao Terreno Santa Helena no Cráton Amazônico, situa-se a cerca de 60 Km a norte da cidade de Pontes e Lacerda, sudoeste de Mato Grosso, apresentando o contato leste e nordeste recoberto pelas rochas sedimentares da Bacia Cretácica Parecis. Encontra-se intrusivo em rochas metamórficas do Complexo Vulcano-sedimentar Pontes e Lacerda em gnaisses e migmatitos ortoderivados (Complexo Metamórfico Alto Guaporé, Maciço Sapé e Anhanguera) de idades mesoproterozóicas. Compreende um corpo de 80 Km2, constituído por três fácies petrográficas graníticas principais, cujos contatos são transicionais. As rochas apresentam composição monzogranítica, são inequigranulares a localmente porfiríticas, granulação dominantemente média, constituídas por microclínio, quartzo, oligoclásio límpido ou saussuritizado , abundantes placas de muscovita (primárias ou secundárias), rara biotita cloritizada e fluorita metassomática, além de titanita e minerais opacos. A Fácies Biotita Monzogranito é dada por rochas equigranulares de granulação média-fina, cor avermelhada, leucocráticas, isotrópicas que ocorrem na porção sul do corpo. A Fácies Muscovita Monzogranito é representada por rochas inequigranulares, granulação média-grossa, cor rósea, hololeucocráticas e isotrópicas, que ocorrem na porção norte e central da intrusão. A ocorrência principal da Fácies Monzogranito aflora no extremo norte da área de forma isolada, como um "plug" granítico e dentro do maciço como diques aplíticos tardios. São constituídas por rochas leucocráticas, róseas, isotrópicas, ineqüigranulares a porfiríticas de granulação fina a média. A tectônica regional com direção NW-SE controla e define a forma alongada do Maciço Sararé acompanhando o trend regional de suas encaixantes. Tardiamente, uma tectônica rúptil manifestada através de fraturas...(Resumo completo, clicar acesso eletrônico abaixo)Abstract: The Sararé Granite belongs to the Santa Helena Terrain within the Amazonian Craton and is located about 60 km north of the city of Pontes and Lacerda, of southwest Mato Grosso. The east and northeast contacts of the body are marked by the sedimentary rocks of the Cretaceous Parecis Basin, while its remaining intrusive contacts are the metamorphic rocks of the Pontes and Lacerda volcano-sedimentary complex and orthogneisses and migmatites (Alto Guaporé Metamorphic Complex, Sapé and Anhangüera Massifs) of Mesoproterozoic age. The areal extent of the instrusion is approximately 80 km2 and is constituted by three major monzogranitic petrographic facies (biotite monzogranite, muscovite monzogranite and monzogranite) whose contacts are transitional. These rocks present monzogranitic composition, are unequigranular to locally porphyritic with medium grain size, constituted by microcline, quartz, oligoclase, abundant muscovite, rare cloritized biotite and metassomatic fluorite plus titanite and opaque minerals. Biotite monzogranitic facies is represented by equigranular of medium to small grain size, red-colored, leucocratic and isotropic rocks, that crop out in the southern portion of the body. The facies of muscovite monzogranite is represented by medium to coarse inequigranular textures, rose-colored, hololeucocratic and isotropic rocks that occur in the north and central portion of the intrusion. Monzogranite facies crops out in its main occurrence in the north end of the area and are interpreted as late-stage granitic plugs, constituted by inequigranular of medium to small grain size to porphyritic leucocratic rosy isotropic rocks. Their occurrence is characterized as localized intrusive bodies, including late aplite dikes, into the other ...(Complete abstract click electronic access below)
Orientador: Antonio Misson Godoy
Coorientador: Maria Zélia Aguiar de Souza
Banca: Tamar Milca Bortolozzo Galembeck
Banca: Mauro Geraldes
Mestre
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Parker, Matthew J. "Early prehistoric petrology: A case study from Leicestershire." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6310.
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This research focused on the petrographic analysis of prehistoric ceramics within the East Midlands. Prior assessments have been intermittent and not drawn together by a research-based agenda, with a few notable exceptions. This research uses petrographic analysis to shed light on early prehistoric society within Leicestershire, a county overlooked in comparison to other regions. The aim of this research was to investigate the procurement of raw materials and the subsequent production of Neolithic and early Bronze Age ceramics in Leicestershire, placing the county in its regional context. Petrographic slides from several early prehistoric sites were produced and analysed to determine the presence of any non-local material within the fabric of the ceramics. Existing petrographic data from other sites in the East Midlands were used as a comparative data set to test whether the ceramics from Leicestershire were typical or atypical of the wider production and procurement pattern. The results of the petrographic analysis on the Leicestershire sites indicated that the clay and inclusions were most likely of local origin, with no definitive evidence for non-local inclusions. However, the results from the comparative petrographic data obtained from sites within the wider East Midlands does support the movement of raw materials and/or finished ceramic products within the region. Preferential sources appear to have been continually exploited, both chronologically and geographically. The prime target of the exploitation was the Charnwood Forest area of Leicestershire, with groups from Derbyshire and Nottinghamshire utilising this resource in addition to more local groups within Leicestershire.
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Porten, Hege Walderhaug. "Petrography, diagenesis and reservoir quality of the Triassic Fruholmen, Snadd and Kobbe formations, southern Barents Sea." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for geologi og bergteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20107.
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Petrographic composition, diagenesis and reservoir quality of the Upper Triassic fluvial to marginal marine Fruholmen Formation, the Middle and Upper Triassic estuarine and coastal plain Snadd Formation, and the Middle Triassic estuarine Kobbe Formation have been examined in wells 7131/4-1 and 7222/11-1 located on the western Bjarmeland Platform and on the eastern Finnmark Platform in the southern Barents Sea. Twenty-nine thin-sections from the Fruholmen Formation, sixty-eight from the Snadd Formation and eleven from the Kobbe Formation were studied with a petrographic microscope, forty were point-counted, and six were studied with a cathodoluminescence microscope. The petrographic observations were compared with plug measurements of porosity and permeability.The Fruholmen Formation sandstones are moderately well and well sorted fine-, medium- and coarse-grained quartz arenites. The Snadd Formation sandstones are moderately well and well sorted and fine- and medium-grained, and the Kobbe Formation sandstones are mostly well sorted and fine-grained. Both the Snadd and Kobbe Formations comprise sublitharenites and lithic arenites with common to abundant metasedimentary rock fragments, but the Snadd Formation contains both K-feldspar and plagioclase, whilst the Kobbe Formation contains plagioclase only. These compositional differences between the three formations may largely be a result of the Snadd and Kobbe formations having had an eastern source area (Uralides), and the Fruholmen Formation a more southerly source area (Scandinavia), although a shift to a more humid climate in the Late Triassic may also have influenced sand composition.The Fruholmen Formation sandstones contain very little diagenetic cement, typically 1-2% quartz overgrowths, traces of pyrite cement, and occasionally 1-2% authigenic kaolin. The main diagenetic cement in the Snadd Formation is early diagenetic chlorite that occurs as grain coatings and more rarely as pervasive microporous pore-filling cement. Siderite is present in most Snadd Formation samples in amounts of 1-6%, and a few thin zones are strongly calcite-cemented. Up to 3% authigenic kaolin is commonly present, and traces of pyrite cement and quartz overgrowths occur. The Kobbe Formation sandstones contain the same diagenetic minerals as the Snadd Formation, plus a few albitic overgrowths on plagioclase. However, the total volumes of diagenetic minerals in the Kobbe Formation are typically very low, 1-5% in the point-counted samples.Diagenetic chlorite or poorly crystalline chlorite precursors may have formed from iron-rich colloidal material brought in by rivers and flocculated where fluvial waters mixed with marine waters. These colloids may also have been the main source for iron in early diagenetic siderite. Partly dissolved biogenic carbonate is still present in the Snadd and Kobbe formations, and carbonate fossils are probably the source of the calcite cement. The calcite cement engulfs and therefore postdates chlorite grain coats, siderite cement and authigenic kaolin. Quartz overgrowths were sourced from dissolution of quartz grains at stylolites evolved from clay laminae when temperatures reached 70-80°C.Reservoir quality is largely excellent in the Fruholmen Formation sandstones (25-32% helium porosity, 1 000-38 000mD permeability) because contents of detrital clay and diagenetic minerals are almost zero. Snadd Formation porosities are also in most cases high to very high, 26-36%, partly due to the chlorite coatings inhibiting quartz cementation. Permeabilities are mostly 100 to 5 000mD, but where microporous diagenetic chlorite fills the pore system permeabilities are very low to low, 0.1-15mD. The Kobbe Formation sandstones have been more deeply buried than the overlying formations, approximately 3.5km, content of soft components (detrital and authigenic clay, mica-rich rock fragments) is high, and compaction has therefore been severe. Porosities are consequently quite low, 15-21%, even in the best of the cored Kobbe Formation sandstones, and together with the fine grain size this results in low permeabillities, 1-20mD.Burial depth for the shallowest examined cores is only 0.4 and 0.56km, and present temperatures are around 30°C. The consolidated nature of these cores and the presence of quartz overgrowths that normally start forming at 70-80°C therefore suggest that the sandstones have been more deeply buried than at present. Lack of illitization of kaolin in the deepest samples indicates that they have not been subjected to temperatures above 130°C. Together with the degree of quartz cementation in the various examined samples this suggests uplift of around 1.5km in well 7131/4-1 and 1.7km in well 7222/11-1. Comparison of the present porosities in the quartz arenites of the Fruholmen Formation with the porosity depth trend for the Garn Formation also suggests 1.5km of uplift in well 7131/4-1.
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Coffin, Lindsay M. "Sedimentology, Stratigraphy and Petrography of the Permian-Triassic Coal-bearing New Lenton Deposit, Bowen Basin, Australia." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23998.
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The Bowen Basin is one of the most intensely explored sedimentary basins in Australia and hosts one of the world’s largest coking coal deposits. This study focuses on the Lenton deposit in the north-central part of the Bowen Basin and targets the Rangal Coal Measures, which are the youngest (245 Ma), most areally extensive and least structurally deformed coal measures in the study area. Six lithofacies were identified from detailed bed-by-bed logging of two cores and stratigraphically-upward comprise peatmire deposits of the Permian Blackwater Group overlain unconformably by braided fluvial strata of the Triassic Rewan Group. Coal-bearing strata of the Blackwater Group form a large-scale drying up sequence showing a change from permanent to seasonal waterlogged conditions related to the onset of regional uplift. Sedimentation was then terminated and a regional erosion surface formed by uplift related to the Hunter Bowen Orogeny. This, then, was overlain by braided fluvial strata of the Triassic Rewan Group.
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Dillet, Brigitte. "Petrography and mineralogy of the granitic rocks associated with questa caldera (new mexico, u. S. A. )." Clermont-Ferrand 2, 1987. http://www.theses.fr/1989CLF21051.
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L'etude petrographique des neuf plutons granitiques associes a la caldera de questa (nouveau mexique) a permis de mettre en evidence l'existence d'une lignee alcaline et d'une lignee calcoalcaline granodioritique a monzonitique l'existence de ces deux series peut etre reliee a l'evolution geodynamique regionale a l'epoque de leur mise en place. Les donnees geochimiques confirment les resultats de l'etude petrographique. Les relations ilmenite-magnetite-sphene et la composition de l'ilmenite, de la magnetite, de la biotite et de l'amphibole ont permis de mettre en evidence des conditions de cristallisation differentes dans les deux series. Les mineraux de la serie alcaline indiquent une cristallisation sous faibles fugacites d'oxygene, souvent fluctuantes, et a des temperatures relativement elevees. Des fugacites d'oxygene plus elevees et des temperatures generalement plus basses sont typiques de la serie calcoalcaline
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Manyeruke, Tawanda Darlington. "The petrography and geochemistry of the Platreef on the farm Townlands near Potgietersrus, northern Bushveld Complex." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-04282005-110052/.
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Landman, Brandon Evan. "Petrography mineralogy and geochemistry of the rock formations of the Zululand Basin based on borehole NZA." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/63301.
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The drill core of borehole NZA, drilled in the southwest margin of the onshore
Zululand Basin to a depth of ca. 571 m was investigated in this study. In this thesis
descriptions of the geochemistry, mineralogy and physical properties of major lithofacies of
the NZA drill core are followed by an interpretation of the suitability of NZA rock units for
injection of carbon dioxide (CO2). A representative NZA sandstone was subjected to reaction
with super critical (sc)CO2 and water under reservoir conditions for two weeks to gain insight
into the effects of rock-CO2 interactions on rock porosity. Rock porosity was estimated by
petrographic study for clastic sedimentary rocks of NZA.
Petrographic study served to identify major lithofacies associations of the NZA drill
core, as well as the depositional environments; interpreted after studying primary
sedimentary structures, chemistry and biogenic features. Trends within the lithofacies were
used to discriminate various formations of the Zululand Group observed in the NZA drill core.
The Zululand Group rocks of the NZA drill core were generally deposited in a shallow shelf
environment, while the pyroclastic rocks of the Fenda Formation identified in the drill core
were deposited in a subaerial volcanic environment. Calcareous sandstones, greywackes,
coquina limestone, beachrock, lapilli-stone, lapilli-tuff, tuff-breccia and tuff were identified as
the major lithofacies of the NZA drill core and are consistent with literature data.
Major element XRF results and mineralogical results formed an integral role in
investigating the chemistry and its effects on the mineralogy of the NZA drill core’s rocks.
Major element analysis was further utilised for discriminating tectonic setting and provenance
of siliciclastic rocks. From geochemical data the source area of the Zululand Group
sedimentary rocks of the NZA core is consistent with the inferred continental rift setting for
the Zululand Basin. The provenance of the NZA drill core’s siliciclastic rocks is consistent
with chemically immature terrigenous detritus, sourced from the proximal Lebombo Group
volcanic rocks.
Borehole NZA was drilled to a relatively shallow depth which is insufficient, when
considering its use for geological storage of CO2. Furthermore, the low porosity of ca. 1-2 %,
identified in the rock samples suggests low storage potential. Dissolution after CO2 injection
may significantly increase porosity after reaction with scCO2 while rock stability could be
severely compromised due to dissolution of carbonates. Lastly, lithologies of the NZA drill
core do not correlate well with the adjacent ZA, ZB and ZC drill core lithologies; thus the NZA
borehole is a seemingly unsuitable site for geological storage of CO2 as CCS technology
requires lateral continuity of suitable rock packages. Further study of the chemistry and
physical properties of the ZA, ZB and ZC drill core could reveal a suitable site for injection of
CO2 in the onshore Zululand Basin.Dissertation (MSc)--University of Pretoria, 2017.
Geology
MSc
Unrestricted
44
Sahlström, Fredrik. "Ore Petrography and Geochemistry of some REE-bearing Fe-oxide Assemblages from the Idkerberget Deposit, Bergslagen, Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-182875.
Full textAbstract:
The mine dumps of Kiruna-type apatite-iron oxide ore in Bergslagen, South Central Sweden, contain elevated amounts of rare earth elements (REEs). A recently started project at Uppsala University has been initiated to study these ores among others in order to document occurrences of REEs and other critical elements in the mine dumps. In this study a selection of samples from the Idkerberget deposit have been studied with respect to their geochemistry and petrography with a special focus on REE-bearing phases. In addition, their mining potential and their relationship to related ore deposits such as Blötberget, Grängesberg and Kiirunavaara have been considered. The bulk geochemistry of the ores was analyzed using ICP-ES and ICP-MS. Polished sections of the ore samples were studied using ore microscopy, SEM-EDS and WDS microprobe technique. The results indicate that the ores consist mainly of magnetite and hematite, with minor silicates, flourapatite, pyrite, chalcopyrite, monazite-(Ce), allanite-(Ce), thorium silicate, titanite and zircon. Most REEs were originally hosted in flourapatite, but metamorphic and/or hydrothermal overprinting has resulted in complex textures and neomineralisation involving exotic REE-bearing minerals such as monazite-(Ce), allanite-(Ce) and secondary flourapatite. These features have also been observed in the related ore deposits nearby. The ores are enriched in REEs by factors between 1 and 9 compared to crustal values, with LREEs being the most enriched. These enrichments are rather low compared to other REE-ores currently being mined, but the easy access to the ores could mean that mining can be profitable with the current demand of these commodities.Varphögar av apatitjärnmalm av Kirunatyp ifrån järnmalmsbrytning i Bergslagen, Sydcentrala Sverige, innehåller förhöjda halter av sällsynta jordartsmetaller. Ett projekt vid Uppsala Universitet undersöker förekomster av sällsynta jordartsmetaller och andra kritiska element i varphögar bland annat från apatitjärnmalmer. I denna studie har prover från ett av Bergslagens apatitjärnmalmsfält, Idkerberget, undersökts geokemiskt och petrografiskt med fokus på faser som innehåller sällsynta jordartsmetaller. Deras utvinningspotential och deras relation till liknande förekomster såsom Blötberget, Grängesberg samt Kiirunavaara har också tagits i beaktning. Bulkgeokemin i proverna analyserades med ICP-EM och ICP-MS. Polerprov av malmerna undersöktes medelst optisk mikroskopi, SEM-EDS samt med WDS-mikrosondteknik. Resultaten visar att malmerna framförallt består av magnetit och hematit, med mindre mängder silikater, flourapatit, pyrit, kopparkis, monazit-(Ce), allanit-(Ce), thoriumsilikat, titanit och zirkon. Sällsynta jordartsmetaller är i huvudsak bundna i flourapatit, men metamorfa och/eller hydrotermala processer har resulterat i nybildningen av exotiska mineral såsom monazit-(Ce), allanit-(Ce), och sekundär flourapatit. Dessa egenskaper har även observerats i apatitjärnmalmer från andra platser. Proverna från Idkerberget har 1-9 gånger högre koncentration av sällsynta jordartsmetaller än jordskorpan generellt, och lätta sällsynta jordartsmetaller är de mest anrikade. Dessa halter är relativt låga jämfört med sällsynta jordartsmalmer som bryts i dagsläget, men eftersom materialet förekommer i enorma varphögar gör tillgängligheten att metallerna ändå kan utvinnas med vinst om efterfrågan på denna resurs består.
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Collins, Krystal Marie. "PETROGRAPHY OF THE COOK-MCCORMICK CORE, HEIDELBERG, JASPER COUNTY, MISSISSIPPI AND RELATIONSHIP TO MICROBIAL PERMIABILITY PROFILE MODIFICATION." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04042008-092608/.
Full textAbstract:
The objective of this study is to characterize heterogeneity, mineralogy, and diagenetic history in the Upper Cretaceous Eutaw Formation of the Heidelberg field Jasper County, Mississippi through analysis of the Cook-McCormick-4 core. The Eutaw Formation in this interval ranges from fine-grained sandstone to siltstone. Interbedded oil-rich sandstone beds are between 1-2 in (3-5 cm) and 3ft (1 m) thick. A few intervals display consistent lithology over as much as 9 ft (3 m), however, in the majority of core beds range from 1-2 inches (3-5 cm) to 2-3 ft (0.6-1 m). Calcite is not present in oil-rich units, suggesting that oil migration impeded diagenesis. This suggests that authigenic minerals found in oil-rich units (feldspar dissolution, pyrite, quartz overgrowths, and siderite) formed prior to reservoir charging or oil emplacement. In all thin sections containing > 60% matrix, it is apparent that glauconite compaction formed pseudomatrix and green clay. The Eutaw Formation is heterogeneous and thus an excellent formation for testing enhanced oil recovery methods, such as Microbial Permeability Profile Modification (MPPM). The reservoir characterization data compiled here in can be applied to analogous units. This project is significant because it will be used to improve secondary and tertiary oil recovery efforts in oil fields located in central Mississippi.
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Huttu, M. (Miika). "Geochemistry and petrography of magnesium-rich intrusive rocks in the Rompas-Rajapalot area, Peräpohja Belt, northern Finland." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201412042100.
Full textAbstract:
The aim of this Master’s project was to describe high-MgO intrusive rocks from the Rompas-Rajapalot area and to find potential analogues among known Paleoproterozoic mafic-ultramafic intrusions that occur in the Karelian schist belts. The focus area of this study, the Rompas-Rajapalot area, is situated in the Peräpohja Belt, northern Finland. The belt represents ~500-Ma-long geologic history and supracrustal rocks that have been deformed in several tectonic events. The Rompas-Rajapalot area is located at the northern margin of the Peräpohja Belt close to the Central Lapland Granitoid Complex and the contact between these units is thought to be tectonic.
The sample material of this study was collected from three drillholes and two outcrops. Thin sections of ultramafic were studied using polarization microscopy and whole-rock major and trace element compositions were determined with X-ray Fluorescence Spectroscopy (XRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).
The primary mineral assemblage has been completely altered in all samples, and the secondary minerals consist mainly of amphiboles (actinolite and tremolite), chlorite, biotite, plagioclase and epidote. Accessory opaque minerals include ilmenite, magnetite, pyrite and pyrrhotite. Some samples reveal clear “porphyritic-looking” texture, in which large clinopyroxene oikocrysts enclose cumulus olivine grains. The presence of metamorphic olivine indicates peak metamorphic conditions of amphibolite facies.
Whole-rock geochemistry shows that the parental magma had Al2O3/TiO2 of ~5.5, Ti/V of ~30, and high LREE/HREE. This together with petrographical similarities suggests that the closest analogues for the studied high-MgO rocks are ultramafic cumulates from the 2.22 Ga Gabbro-Wehrlite Association intrusions. This conclusion has stratigraphic implications that calls for a reappraisal of the structure of the northern part of the Peräpohja Belt.
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Lötter, Francois Jacobus Petrus. "Petrography and geochemistry of the Holocene monogenetic Bayuda Volcanic Field, Sudan: Insights into the magma plumbing system." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/75521.
Full textAbstract:
The Bayuda monogenetic volcanic field (BMVF) is an active, understudied Holocene volcanic field located in the great bend of the Nile, Sudan. The BMVF’s location provides an excellent opportunity to study monogenetic volcanism in an African context. Recent studies have shown that monogenetic volcanoes can have more intricate plumbing systems than initially thought. The project sets out to provide a general description and genesis of the BMVF emphasising the plumbing system. Petrography reveals olivine and clinopyroxene as the main phenocryst phases in a groundmass of predominantly plagioclase and subordinate pyroxene and olivine microcrysts. A significant amount of crystals display pronounced disequilibrium textures alongside sector and oscillatory zoning. Major and trace elements indicate that the BMVF is sodic-alkaline, resembling an OIB signature. Melting models that use partitioning coefficients of Zr, Hf and Nb in phenocrysts estimate 2-4% melting of a metasomatised garnet pyroxenite at a depth of ~2.8GPa as the source melt for the BMVF.
The isotopic signature suggests mixing of an enriched mantle component (HIMU) and a depleted mantle component (DMM). Textural evidence alongside KD (Fe-Mg) of olivine indicate open system dynamics by revealing separate magma batches with differing times and depths of emplacement. Ni, Ca and Mn content of olivine, furthers the idea of open system dynamics by revealing processes of 1) ‘failed eruptions’, 2) magma mixing and 3) deep-seated fractionation. This project forms part of a growing number of studies that suggest complex plumbing system for monogenetic volcanic fields.Dissertation (MSc)--University of Pretoria, 2020.
Geology
MSc
Unrestricted
48
Thornberry, Trista L. "The Petrography of the Buck Creek Dunite Body, Clay County, NC : Implications about its Origin and Emplacement." Oberlin College Honors Theses / OhioLINK, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1411990381.
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Chiarini, Veronica <1988>. "Exploring Holocene Climate Signals Recorded in Stalagmites from Bosnia. A Multi Proxy Approach Coupling Petrography and Geochemistry." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8099/1/chiarini_veronica_tesi.pdf.
Full textAbstract:
The Mediterranean area is a densely populated region characterised by an extremely complex atmospheric circulation, which is particularly sensitive to any modification of air mass dynamics. Thus, the understanding of past climate fluctuations in this area is of great importance to gain insight in the pattern of regional climate variability in response to global climate changes. The central Mediterranean area displayed contrasting climatic responses to atmospheric circulation re-organization following the last glacial period: drier/wetter conditions lasted until about 4.5 ka in the northern/southern regions, followed by an opposite trend.
To better understand Holocene climate dynamics in the Balkans, a region where only few palaeoclimate reconstructions are available, five stalagmites were collected from two Bosnian caves. Rainfall and cave monitoring was set up in order to understand present day cave hydrology and better interpret the climate and/or environmental signal transfer to the karst.
All stalagmites were dated using the U-Th method. Stable carbon and isotope ratios were analysed along the growth axis. Indeed, these values can provide information about temperature, precipitation regime and vegetation cover if calcite is deposited close to isotopic equilibrium conditions. Unfortunately, stable isotope profiles were noisy and not interpretable straightforwardly. Therefore, a multi proxy approach was adopted, coupling stable isotope and trace element profiles with detailed petrographic observations. This allowed for the interpretation of geochemical proxies and petrography variations in relation to hydrological changes. In particular, a trend towards relatively drier conditions appears since about 4 kyr, suggesting a local response to climate change similar to the one of the southern Mediterranean sites.
A marginal part of this project involved the examination of a dark lamina deposited around 1.2 ka in the 4 samples from Mračna Pećina cave. This layer, appearing fluorescent under the fluorescence optic microscope, was identified with SEM observation, which demonstrated its soot nature.
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Parker, Matthew John. "Early prehistoric petrology : a case study from Leicestershire." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6310.
Full textAbstract:
This research focused on the petrographic analysis of prehistoric ceramics within the East Midlands. Prior assessments have been intermittent and not drawn together by a research-based agenda, with a few notable exceptions. This research uses petrographic analysis to shed light on early prehistoric society within Leicestershire, a county overlooked in comparison to other regions. The aim of this research was to investigate the procurement of raw materials and the subsequent production of Neolithic and early Bronze Age ceramics in Leicestershire, placing the county in its regional context. Petrographic slides from several early prehistoric sites were produced and analysed to determine the presence of any non-local material within the fabric of the ceramics. Existing petrographic data from other sites in the East Midlands were used as a comparative data set to test whether the ceramics from Leicestershire were typical or atypical of the wider production and procurement pattern. The results of the petrographic analysis on the Leicestershire sites indicated that the clay and inclusions were most likely of local origin, with no definitive evidence for non-local inclusions. However, the results from the comparative petrographic data obtained from sites within the wider East Midlands does support the movement of raw materials and/or finished ceramic products within the region. Preferential sources appear to have been continually exploited, both chronologically and geographically. The prime target of the exploitation was the Charnwood Forest area of Leicestershire, with groups from Derbyshire and Nottinghamshire utilising this resource in addition to more local groups within Leicestershire.