A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. 25th of July 2013, Johannesburg. / The cave deposits at Malapa, on the Malapa Nature Reserve, Cradle of Humankind World Heritage Site, Gauteng Province, South Africa, have yielded the remains of two extremely well-preserved hominins (Australopithecus sediba) and associated fauna, dated by U/Pb methods and palaeomagnetism to 1.977-1.8 Ma. The state of preservation of the hominins and some of the non-hominin material, characterised by complete and near complete elements, antimeric sets of bones, specimens in articulation, and well-preserved bone surfaces, is remarkable in the context of Plio-Pleistocene fossil assemblages accumulated in caves, and indicates a unique combination of taphonomic processes, not yet observed in contemporaneous cave deposits in the region. A comprehensive approach, including palaeontological, physical, and spatial analyses of the hominins and associated fauna was undertaken to determine, describe and interpret the taphonomy of the faunal material, with particular reference to the holotype and paratype of Au. sediba, Malapa Hominin 1 (MH1) and Malapa Hominin 2 (MH2). An innovative combination of Computed-Tomography (CT), micro-CT scanning and virtual reconstruction techniques was applied to create a 3D model of a selected area of the Malapa cave, with renderings of the two near-complete Au. sediba skeletons. The original burial position of the hominins was reconstructed, which necessitated the refitting of ex situ fossils into in situ deposits. The spatial distribution and orientation of the hominin remains illustrate a very low degree of dispersal of the bones, indicative of very little disruption between death and burial, due to an absence of damage by scavengers and possible natural mummification. The very few carnivore-damaged bones and relative abundance of complete and/or articulated specimens, the presence of antimeric sets of bones in the faunal assemblage, as well as the diversity of the faunal spectrum, and the significant percentage of animals with climbing proclivities (such as carnivores and hominins) indicate that the majority of the faunal material recovered was most likely accumulated via a natural death trap. Their bodies came to rest in a deep area of the cave system with restricted access to iii scavengers. Skeletons and bones accumulated in a talus cone below a vertical shaft. There, they decomposed, and became buried without major disruption by biotic or abiotic agents. A new forensic approach, referred to as palaeoforensic taphonomy, was followed in each step of the taphonomic analysis of the two hominins in order to reconstruct the processes of decay, disarticulation, burial and preservation. Results show that both individuals did probably not enter the cave system at the same time. They reached skeletonization and were slightly weathered before final burial, indicating several years of exposure before burial. Insects proved to be the primary modifiers of the hominin remains, pre- and post-depositional with hide beetles (Omorgus squalidus) providing the closest match for some of the fossil modifications observed. Based on the high number of articulated remains, the absence of preferential orientation for the elongated bones and of significant movement of the hominin remains inside the deposit, the debris flow hypothesis that was previously proposed as the principal agent to explain the burial of the hominins and other well-preserved animals is challenged. Evidence of natural mummification before burial for MH1 and MH2 suggests the possible preservation of soft tissue. The innovative 3D techniques applied in this research to conduct the spatial analysis of the fossils proved useful to address taphonomic questions, and will serve as a guide for future excavations of the Malapa in situ deposits, especially for locating the missing skeletal elements of MH1 and MH2.

Le carbone est un élément essentiel à la surface de la Terre. Il entre aussi bien dans la composition de certains minéraux (carbonates) que dans les molécules du vivant. Les roches métamorphiques contiennent également des matériaux carbonés (MC) dont l’origine peut être variée. Les MC sous forme solide (matériaux carbonés partiellement ou parfaitement graphitisés) jouent un rôle majeur dans l’évolution pétrologique et géochimique d’une roche enfouie en zone de subduction. Si notre connaissance des MC métamorphiques a largement progressée ces dernières années sur la base d’études naturalistes, expérimentales ou théoriques, il reste de nombreuses questions par exemple autour de la détermination des sources des MC dans les roches métamorphiques. Le rôle des minéralisations en tant que facteur de préservation des MC d’origine biologique (biogénique) est encore mal compris. Nous avons étudié des échantillons naturels (formation Marybank, Nouvelle Zélande) métamorphisés dans le facies schiste bleu et contenant des fossiles végétaux graphitisés et montrant une remarquable préservation morphologique. Nous dressons ainsi un inventaire des processus minéralogiques et chimiques ayant contribué à préserver, ou oblitérer, certaines informations portées par le matériau biologique originel, et plus généralement par le fossile. Pour ce faire, nous avons employé des techniques de caractérisation minéralogiques et géochimiques à haute résolution spatiale des MC fossiles et des minéraux. Nous montrons ainsi que la remarquable préservation morphologique s’accompagne d’une recristallisation avancée de la minéralogie et des MC constituant le fossile. Nous mettons aussi en évidence la présence spectaculaire de nanoparticules de TiO2 dans les MC des fossiles et nous discutons des mécanismes possibles de formation de ces minéralisations exceptionnelles.Il existe des mécanismes complexes, abiotiques, fortement liés aux interactions fluide-roche et permettant la formation de MC graphitiques dans les roches métamorphiques. Ces processus rendent complexe l’étude et l’interprétation des MC dans les roches. Toutefois, ils révèlent le rôle majeur des fluides et des assemblages minéraux dans la dynamique métamorphique du carbone. Nous avons réalisé l’étude détaillée d’un contact entre des serpentinites et des métasédiments (Malaspina, Corse Alpine) au niveau duquel les métasédiments sont décarbonatés. A cause des conditions réductrices imposées par les serpentinites sous-jacentes, le carbone inorganique ainsi libéré précipite sous forme de graphite. Nous employons des méthodes géochimiques, minéralogiques et pétrologiques complémentaires qui permettent de distinguer différentes catégories de matériaux carbonés dans ces roches, mais aussi de proposer un scénario bien contraint de formation abiotique du graphite. Cette étude permet alors de discuter du rôle des gradients redox sur la dynamique du carbone dans une roche métamorphique. L’ensemble de ces travaux sont autant d’exemples qui soulignent certains aspects encore peu explorés du rôle pétrologique fondamental des MC dans les roches métamorphiques. / Carbon is an essential element on the Earth’s surface. It is involved in the formation of certain minerals (carbonates) as well as biomolecules. Metamorphic rocks also contain carbonaceous materials (CM) with various possible origins. Solid CM (partially or completely graphitized CM) play a major role in the petrological and geochemical evolution of a subducted rock. If our knowledge of metamorphic CM increased over the last years based on naturalist, experimental or theoretical studies, many issues remain as to the source of CM in metamorphic rocks for example.The role of mineralization as a factor of preservation of CM of biological origin (biogenic) is still poorly understood. We studied natural samples (Marybank formation, New Zealand) metamorphozed in the blueschist facies and which contain carbonaceous plant fossils that display a remarkable morphological preservation at the microscopic scale. We investigate mineralogical and chemical processes that contributed to preserve, or obliterate, information carried by the original biomaterial, and, more generally, by the fossil. To do so, we have characterized the fossils and the minerals using analytical technics with high special resolution. We show that the remarkable morphological preservation is accompanied by the advanced recristallization of the mineralogy compositing the fossils. We also show the presence of spectacular TiO2 mineral nanocristals in the CM composing the fossils and we discuss about possible mechanisms leading to the formation of these exceptional mineralizations.Complex abiotic processes, intimately linked to fluid-rock interactions, allow the formation of graphitic CM in metamorphic rocks. These processes hinder the study and interpretation of CM in rocks. Nevertheless, they also reveal the major role of fluids and mineral assemblages in the metamorphic dynamics of carbon. We carried a detailed study of a contact between serpentinites and metasediments (Malaspina, Alpine Corsica) that display complete carbonate destabilization. Because of the reduced conditions imposed by the underlying serpentinite, the inorganic carbon released has precipitated and formed graphite. We use geochemical, mineralogical and petrological complementary tools that allow to distinguish different categories of CM in these rocks, and we propose a well constrained scenario for the formation for this abiotic graphite. This study allows discussing the role of redox gradients on the dynamics of carbon in a metamorphic rock.These are all examples stressing the important, and yet poorly explored, petrological role of CM in metamorphic rocks.

No description available.

Second language acquisition (SLA) is seldom entirely successful with adult learners. It has been suggested that all second language (L2) learners, in the process of mastering a target language (TL), develop a linguistic system that is self-contained and different from both the learner's native language and the TL. This system is referred to as 'interlanguage' (lL). In the process of SLA, IL evolves into an ever-closer approximation of the TL, and ideally, a learner's IL should continue to advance until it becomes equivalent to the TL. However, it has been observed that somewhere in the L2 learning process, IL may reach one or more plateaus during which the development of the IL is delayed or arrested. A permanent cessation of progress toward the TL is referred to as 'fossilization'. Researchers in SLA agree that motivation is one of the key factors influencing language-learning success and studies suggest that some language learning motivation may be related to the need for achievement. The purpose of this research was to establish if adult ESL learners are aware of fossilization and, to examine if motivation, and more specifically achievement motivation, is a factor in IL fossilization. The participants in this study consisted of 15 ESL learners in Puerto Rico who had at least eight years of formal ESL training. The instrument used to gather information included a questionnaire to obtain demographical and qualifying data, an 'English Language Proficiency Evaluation' to determine levels of IL fossilization, a 'Measure of Achievement Motivation' to ascertain achievement motive, and individual and group interviews in order to ascertain perception(s) regarding the role of motivation on fossilization and perceptions regarding the barriers to achieving TL competency. The research demonstrated that there is a moderate to strong positive relationship between IL fossilization and achievement motivation, i.e., high achievement motive is correlated to TL competency and descending levels of achievement motive are correlated to ascending levels of IL fossilization. The findings have significant implications for both ESL learning and instruction, and suggest that not all IL fossilization may be permanent.

This study investigates error fossilisation in the written English of Xhosa - speaking students. It is hypothesised that there is no statistically significant difference in the language errors of two groups of Grade 10 and Grade 12 students. Two randomly selected groups of 30 Grade 10 and 30 Grade 12 students in a rural senior secondary school in the Eastern Cape province were required to write two essays, of which the first two hundred words of each essay were marked. A frequency count of errors was done and comparisons were made. The findings indicate that the Grade 12s consistently made fewer errors. However, the difference is only statistically significant in the case of prepositions and concord, and is insignificant in tenses, pronouns and articles. The findings also show evidence of fossilisation given the persistence of some of the errors. Certain features in the student's language were not eradicated by the additional two years exposure to English. / English Studies / M.A. (Teaching English to Speakers of Other Languages)

This study investigates error fossilisation in the written English of Xhosa - speaking students. It is hypothesised that there is no statistically significant difference in the language errors of two groups of Grade 10 and Grade 12 students. Two randomly selected groups of 30 Grade 10 and 30 Grade 12 students in a rural senior secondary school in the Eastern Cape province were required to write two essays, of which the first two hundred words of each essay were marked. A frequency count of errors was done and comparisons were made. The findings indicate that the Grade 12s consistently made fewer errors. However, the difference is only statistically significant in the case of prepositions and concord, and is insignificant in tenses, pronouns and articles. The findings also show evidence of fossilisation given the persistence of some of the errors. Certain features in the student's language were not eradicated by the additional two years exposure to English. / English Studies / M.A. (Teaching English to Speakers of Other Languages)

(anglicky): This diploma thesis describes the bilingualism of immigrants from Bosnia and Herzegovina, Montenegro, Croatia and Serbia living in Czechia. Immigrant bilingualism is examined from a social, cultural and linguistic point of view. The thesis consists of three chapters. The first chapter describes migration from a theoretical and historical point of view. This chapter describes the migration waves from the area of Bosnia and Herzegovina, Montenegro, Croatia and Serbia in Czechia. The second chapter focuses on the description of the selected research methodology, and also on the description of individual parts of research planning, i.e. it describes the purpose of the research, criteria for selecting research questions and criteria for selecting respondents, as well as selecting research site and research material. The third chapter focuses on the research itself. The first part of this chapter briefly describes the basic concepts related to bilingualism and language adaptation. The second part of the third chapter focuses on the description of the course and analysis of the research results in terms of social, cultural and linguistic adaptation of individuals.

The objective of this project is to investigate the items and factors that may be prematurely stabilized in advanced adult second-language learners' interlanguage, in order to propose effective instructional interventions.

Linguistic fossilization is a prevalent phenomenon in adult ESLA and presents a perpetual pedagogical challenge to teachers. Despite controversy about the theoretical concept, research is increasingly showing that persistent erroneousness cannot be attributed to single causal factors. This single case study examines controversial aspects surrounding the concept and formulates criteria for identifying fossilization. The study investigates the conversational output of an independent adult learner over a period of nine months and presents a holistic exploration of causal influences. The findings substantiate that fossilization arises from changing combinations of factors, and that such combinations are unique to the situation of each adult learner. The key to the successful treatment of fossilized errors may lie in identifying their roots, which can be achieved by analyzing output and through discussion with learners in order to gain insight into their experience of the learning process. Results also suggest that a critical perspective on the theoretical construct is needed in order to investigate the phenomenon in adult second language acquisition. / Linguistics / M.A. (Teaching English to Speakers of Other Languages (TESOL))

No description available.