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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

High-latitude sedimentation in response to climate variability during the Cenozoic

Varela Valenzuela, Natalia Ines 03 January 2024 (has links)
Here we investigate sedimentological responses to past climate change in shallow to deep marine depositional environments. Our primary study spans from the Late Pliocene to the Pleistocene (3.3 to 0.7 Ma), and features results from two International Ocean Discovery Program (IODP) Sites U1525 and U1524. Each of these sites is discussed in separate chapters here (Chapters 1 and 2). This interval experienced the change from the warming of the Late Pliocene, known as the Mid-Piacenzian Warming Period, to the Pleistocene cooling. This shift significantly impacted the expansion of the West Antarctic Ice Sheet, sea ice/polynya formation, and, notably, the genesis of Antarctic Bottom Water (AABW), a crucial component of the global thermohaline circulation. In Chapter 1, we propose that turbidite currents, arising from the formation of dense shelf water (DSW) in the Ross Sea (a precursor to AABW), leave a distinct record in the levees of Hillary Canyon. This canyon acts as a conduit, channeling DSW into the deep ocean and contributing to AABW production. By analyzing turbidite beds based on their frequency, thickness, and grain size, we gain insights into the historical occurrence and magnitude of these currents. Furthermore, we explore the influence of factors such as shelf availability and sea ice/polynya formation within the broader climate context of AABW formation. Chapter 2 shifts its focus to the sedimentological variability from shelf-to-slope along Hillary Canyon. This chapter examines the turbidite record associated with AABW formation within the shared timeframe (2.1 to 0.7 million years ago) between IODP Sites U1524 and U1525, and the impact of along slope currents and other processes in the sedimentary deposition and transport. The second study interval (Chapter 3), focuses on the regional sedimentological response proximal to a hydrothermal vent complex associated with the Paleocene-Eocene Thermal Maximum (PETM; ca. 56 Ma), a global warming event during which thousands of Gt C was released into the ocean-atmosphere on Kyr timescales. IODP Site U1568, strategically located near the hydrothermal vent complex and part of a broader drilling transect in the Modgunn Arch, North Atlantic, is the main study subject. This site's proximity to the vent complex offers a distinctive environment for refining our understanding of stratigraphy and sedimentology within the PETM. We achieve this through a comprehensive analysis of grain size and composition, coupled with a comparison to XRF data. Our findings show that the timing between the onset of the PETM and the response of the sedimentary system to the warming, reflected in the grain size coarsening after the start of the PETM, is not synchronous. Notably, the transition from a marine to a more terrestrial composition predates this shift in grain size, aligning with the PETM onset instead. / Doctor of Philosophy / Deep-marine core records are invaluable sources of sedimentological information that provide insights into the ocean's response to past climates. These cores, extracted from the deep-ocean floor, contain layers of sediment that accumulate over time because of the different processes that occur in the ocean. Analyzing these sediments, by looking at their physical characteristics like how frequently are they deposited, the thickness of the layers, their grain size, and their composition helps to reconstruct past environmental conditions and understand how the oceans have responded to climatic changes. This dissertation focuses on studying the record of two main processes. The first one is the sedimentary record left behind by the formation of Antarctic Bottom Water (AABW), one of the coldest (-1°C), deepest (> 2000 meters below sea level), and densest water masses in the ocean. AABW is a key component of the global ocean circulation system, often referred to as the "global conveyor belt" or the thermohaline circulation. This circulation pattern plays a crucial role in redistributing heat, salt, and nutrients around the world's oceans. AABW is formed near Antarctica through a process that begins with the cooling and sinking of surface waters near the continent. As these waters sink, they become denser and eventually form AABW, filling the deep ocean basins around Antarctica. The dense water flows from the surface to the bottom of the ocean forming turbidity currents. These turbidity currents, dense plumes of water and sediments, flow down submarine conduits, such as Hillary Canyon in the Ross Sea, Antarctica, leaving a sedimentary record in the levees or flanks, called turbidites. The turbidite sequences in sediment cores can reveal information about the frequency and magnitude of these currents, providing insights into the sediment transport processes in deep-marine settings, and for this work, the history of the AABW formation over the last 3.3 Ma. This study will help to understand what are the main controls for AABW formation across different climates in the past, and how we project this into the future climate scenarios. In the second part of the study (Chapter 3), we look at the sedimentary record of a warming event that happened around 56 million years ago. This event, known as the Paleocene-Eocene Thermal Maximum (PETM), involved a significant amount of carbon being released into the air and oceans over thousands of years (150,000 to 200,000). Our focus is IODP Site U1568, located near a submarine hydrothermal vent, and part of a larger drilling transect in the North Atlantic's Modgunn Arch. The vent's unique location provides a crucial perspective for understanding how the system responded to the warming during the Paleocene-Eocene Thermal Maximum (PETM). This warming event was triggered by the release of carbon into the atmosphere, with the vent serving as one of the conduits for this release. To understand this, we studied the grain size and content of the sediment, and compared that with XRF data. Changes in grain size serve as indicators of shifts in the energy of the environment – coarser grains signify a more energetic system. Warmer weather, for instance, can increase precipitation, leading to more erosion and sediment influx into the basin. This influx also brings in more materials from the land, as evidenced by the presence of microfossils and plant fragments. Our discoveries indicate that the sedimentary system responded gradually to the PETM, as reflected in the coarsening of grain size after the PETM's onset. Notably, the transition from a marine to a more terrestrial composition occurred before the change in grain size, aligning more closely with the initiation of the PETM itself.
92

Registro fóssil de podocarpaceae na ilha Rei George e a sua relação com os eventos paleoclimáticos e paleoambientais

Fontes, Daiana January 2008 (has links)
Submitted by Fabricia Fialho Reginato (fabriciar) on 2015-07-03T22:44:25Z No. of bitstreams: 1 DaianaFontes.pdf: 25455596 bytes, checksum: 4dae1fc6ad9f052e0a07f54f6be98834 (MD5) / Made available in DSpace on 2015-07-03T22:44:25Z (GMT). No. of bitstreams: 1 DaianaFontes.pdf: 25455596 bytes, checksum: 4dae1fc6ad9f052e0a07f54f6be98834 (MD5) Previous issue date: 2008 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A composição e a diversidade dos representantes de Podocarpaceae nas tafofloras da ilha Rei George, norte da Península Antártica, atestam a importância deste grupo de coníferas nesta região no início do Cenozóico, após uma longa história evolutiva e uma origem igualmente ligada às altas latitudes do sul. O registro fóssil demonstra uma adaptabilidade e capacidade para conquistar novas áreas, diferentemente das outras famílias modernas de gimnospermas austrais, provavelmente devido à dispersão zoocórica e a variedade de formas e hábitos que ainda hoje mantém e que garantiram sua sobrevivência em praticamente todas as faixas de temperatura e gradientes altitudinais. Sete formas relacionadas a esta família foram descritas e se caracterizam pelos dois tipos principais de ramos, ainda hoje existentes. O primeiro deles caracterizado por folhas bifacialmente aplainadas, pequenas e mais ou menos adpressas, representados por duas espécies de Lepidothamnus sp., por Halocarpus sp. e Dacrycarpus sp. O outro grupo, com folhas grandes, com disposição bilateralmente aplainada e com uma veia média destacada, está representado por formas dos gêneros Saxegothaea e Podocarpus, para o qual uma nova espécie é pela primeira vez comunicada. Os macrorrestos estão preservados como impressões e carbonizações em dois dos principais locais da ilha que expõem as litologias durante o verão, o Monte Wawel, na baía do Almirantado, e o Morro dos Fósseis, na península Fildes. Representam sucessões vulcânicas e vulcanoclásticas, englobadas em duas unidades litoestratigráficas distintas, mas provavelmente correlacionáveis, as formações Fossil Hill e Vièville Glacier. Os níveis fossilíferos são compostos por grãos de origem vulcânica, retrabalhados ou não, que atestam sua afinidade com ambientes tectonicamente perturbados e com áreas baixas, de solos rejuvenescidos, onde havia condições para a formação de pequenos lagos e deltas durante as fases de erupções. O levantamento e comparação com outras paleofloras austrais e as idades radiométricas disponíveis permitiram propor uma idade Eoceno Médio para os diferentes níveis onde as podocarpáceas estão presentes e a vigência de um clima temperado úmido que, de modo relativamente rápido, dá lugar a evidências de queda nas temperaturas. A análise dos comparativos modernos sugere que compunham uma flora única, mista e diversificada, que reúne elementos com hábitos e adaptações distintas, se desenvolvendo em diferentes gradientes altitudinais, mais uma evidência em apoio à presença de áreas altas (vulcões?) e costeiras. Quando comparada aos modernos biomas, a paleoflora da ilha Rei George também exibe uma mescla de elementos, unindo hoje os que estão distribuídos nos dois extremos do Hemisfério Sul (América e Australásia), em grande parte endêmicos, e que vivem em lugares submetidos a baixas temperaturas. Assim ao mesmo tempo em que apóia condições climáticas semelhantes para o norte da Península Antártica durante o Eoceno, evidencia o importante papel que as terras do Gondwana e sua separação tiveram, sobre a moderna distribuição disjunta dos representantes desta família. / The composition and diversity of the Podocarpaceae representatives in the fossil plant assemblages of King George Island, north of Antarctic Peninsula, indicates their importance in that region during the Early Cenozoic, after a long evolutive history linked, since its origin, to the high southern latitudes. The fossil record attest an adaptability and capacity to conquer new areas that have no comparatives in other austral conifers, probably due to their seed dispersion by distinct groups of animals and the diverse forms and habits that their modern relatives still maintain. It guarantees their survival until today and their adaptation in nearly all latitudinal and altitudinal gradients. Seven distinct forms related to this family were described, characterized by two main kinds of leaf shoots. Those with scale and short leaf, bifacial flattened shoots are represented by two species of Lepidothamnus and by Halocarpus, Microcachrys and Dacrycarpus. The other one, with bilaterally flattened and big size leaves, with a sharp midrib, was associated with Saxegothaea and a species of Podocarpus, wich was for the first time described in the island taphofloras. The macrofossils are preserved by impressions and charcoalified materials, in the two main areas of the island where the lithologies are exposed in summer seasons, the Mount Wawel, at Admiralty Bay, and the Fossil Hill, at Fildes Peninsula. Represents what was included in two probably correlative lithostratigraphic units established in previous geological works, the Vièville Glacier and Fossil Hill formations. The fossil levels are composed mainly by volcanic grains, sometimes with signals of reworking by shallow lakes and deltas and confirm an environment and deposition linked to moments of active volcanism and inter-eruption phases. The comparisons with other fossil floras from the Antarctic Peninsula and Circum-Antarctic areas, and the radiometric ages indicates a probable lower mid-Eocene age, and wet and temperate climatic conditions, which deteriorates along the succession. The nearest modern relatives of the fossil taxa preserved in the taphofloras suggests also an unique, mixed and diversified vegetation, joining elements with distinct habits and that lives today in distinct altitudinal gradients, provides further evidence in support of the presence of high (volcanoes?) and coastal areas. The King George Island paleoflora flora also comprises a mixture of endemic, eastern Gondwana and South American elements, which reflect its position close to a major floristic boundary. At the same time confirms the microthermic conditions of climate in the north of Antarctic Peninsula at the Eocene times and the important role of the Gondwana drift apart, and the derivate climatic changes, in the modern disjunct distribution of the family.
93

Etude des relations entre l'altération et la couleur des sédiments à travers deux exemples : la molasse rouge oligocène de Barles et les sables éocènes du Royans (Alpes françaises)

Nguyen, Van Tri 05 February 1988 (has links) (PDF)
Cette étude a été effectuée sur deux formations dans les Alpes françaises: a) La Molasse rouge oligocène de Barles qui est un dépôt fluviatile (alternance de grès silteux et de marnes, de silts et de marnes dans la plaine d'inondation; grès dans les chenaux), dont la couleur originelle de cette molasse est grise. b) Les Sables éocènes du Royans dont la couleur originelle est blanche. La coloration rouge de ces deux formations est authigène et se produit par des processus postérieurs aux dépôts. Les analyses de la diffractométrie X, de microscopes (polarisant et microscope électronique à balayage) et de géochimie montrent que la nature des minéraux parents du fer est différente entre ces deux terrains mais leurs processus de rubéfaction sont les mêmes. 1) Nature des minéraux parents du fer: Dans la Molasse rouge, le minéral parenté du fer est la glauconie détritique. Dans les Sables éocènes, ce sont, d'une part, des minéraux ferromagnésiens détritiques et d'autre part, des produits d'altération. 2/ Processus: Après leurs dépôts, les sédiments de ces deux formations subissent les mêmes processus de la coloration en rouge: * Altération par hydrolyse des minéraux parents du fer, cette altération est liée à l 'eau percolée et au milieu oxydant de la surface. Car le faciès rouge se trouve toujours au sommet de la formation et la teneur en minéraux parents du fer diminue du faciès originel au faciès rouge. Cette altération se produit dans un milieu acide confirmé par la néoformation de la kaolinite (plaquettes hexagonales et les feuillets en accordéon) . * Deshydratation de goethite: La goethite existe dans le faciès rouge depuis la limite inférieure, alors que l'hématite se développe de plus en plus vers le sommet de ce faciès. Ceci montre que les minéraux parentés du fer libèrent du fer ferrique qui cristallise en goethite et cette dernière se des- hydrate en hématite. * Un lessivage étant simultané avec cette altération provoque un départ vers le bas de certaines espèces chimiques telles que Si02, Na20 et une accumulation au sommet des autres, Al203,Fe203, Ti02. Ce lessivage est marqué par la forme de pénétration du faciès rouge dans le faciès originel. Les autres phénomènes observés sont la transformation des argiles, l'épigenèse calcitique et la dissolution du quartz.
94

Late Eocene through Oligocene calcareous nannofossils from the paleo-equatorial Pacific Ocean – taxonomy, preservation history, biochronology and evolution

Blaj, Teodora January 2009 (has links)
This study aims to unravel the ecological and evolutionary dynamics within the calcareous nannofossil communities at the Eocene/Oligocene (E/O) transition and during the Oligocene time when Cenozoic 'icehouse' conditions were established. The main question this study aims to answer is whether the changes in the nannofossil assemblages were controlled by intrinsic evolutionary trends or if the changes were controlled by environmental factors such as changes in temperature and nutrient availability in the surface water. These questions are addressed with detailed analyses of the taxonomy, biostratigraphy and fluctuations in abundance and diversity of calcareous nannofossil assemblages from a continuous latest Eocene through Oligocene sediment section from the ODP Site 1218 (8°53.38´N, 135°22.00´W), paleo-equatorial Pacific Ocean. An improved nannofossil taxonomy and biostratigraphy has been established. At the E/O transition, changes in the nannofossil preservation mimics changes in calcium carbonate content. A detailed investigation of late Eocene and Oligocene sediments yields age estimates for ten nannofossil bioevents. Morphometric studies of the Reticulofenestra umbilicus-R. hillae show that these cannot be subdivided into two different morphospecies. Based on different morphometry and stratigraphic ranges, the Oligocene Sphenolithus lineage appears to be the result of a combined anagenetic and cladogenetic evolution. A new nannolith species is described: Triquetrorhabdulus longus. High-resolution nannofossil data indicate changes in the composition, abundance and diversity of the mid-Oligocene assemblages. Intervals of high diversity index coincide with Oi-glaciation events. However, visual examination of the variations in abundance of nannofossil taxa do not appear to correlate with changes in either oxygen or carbon isotopes. This presumably indicates that a dynamic equilibrium did not exist between these Oligocene nannoplankton assemblages and changes in surface water temperature or productivity conditions. / Doctoral Thesis in Marine Geoscience at Stockholm University, Sweden 2009
95

Depositional and diagenetic processes in the formation of the Eocene Jackson Group bentonites, Gonzales County, Texas

Michaelides, Michael Nicholas 17 February 2012 (has links)
Bentonite clays are exposed in Paleogene strata stretching over 650 km parallel to the Texas coastline. This study focuses on a white and blue and a yellow and brown commercial Ca-montmorillonite bentonite near the city of Gonzales, Gonzales county, Texas. The deposits have stratigraphic ages of Late Eocene (~36.7 - 32.7 Ma). The bentonites in these deposits have varying colors, purities and brightness affording them diverse industrial uses. The distribution and geologic character of the high purity white and blue bentonite suggests that the deposit represents an accumulation of volcanic ash in a secondary tidal channel during the ash-fall event. A low rate of terrigenous clastic sedimentation and rapid accumulation of fresh ash were critical to the formation of high purity clay. The lower purity yellow and brown bentonites appear to have a fluvial origin marked by higher rates of detrital sedimentation and episodic accumulation of clay and ash. The bentonite and associated strata were studied using optical microscopy, SEM, XRD and REE analyses to constrain their textural, mineralogic, and chemical character. vii Eocene pyroclastic volcanism is well documented from sources in southwestern North America, specifically in the Sierra Madre Occidental (Mexico), Trans-Pecos (Texas) and Mogollan-Datil (New Mexico) volcanic fields. Projected Eocene wind patterns support this region as a potential source for the Gonzales bentonites. A comparison of the trace and REE fingerprints of the white and blue bentonites and the yellow and brown bentonites with data available for Late Eocene volcanics in the North American Volcanic Database provides a couple of potential matches. The strongest potential match for the Late Eocene bentonite protolith is described as a sample of silicic tuff with an age range of 32.2 – 30.6 Ma, located in the southern Mexican state of Oaxaca. While the trace and REE match is strong, the tuff is somewhat young compared to the Jackson Group sediments. In addition, the sample location is due almost directly south of the Gonzales deposits, rather than the western location expected for a Gonzales bentonite source. The other potential matches are located in New Mexico, and the Mexican state of Chihuahua. These potential matches only have 6 REE available for comparison, and require further investigation. Many Paleogene volcanic units in southern North America are undocumented with regard to REE data or precise absolute ages. As additional geochemical analyses become available for a more extensive suite of Paleogene volcanic units, stronger matches with Gulf of Mexico Basin bentonites are expected to emerge. / text
96

Ein Datenbanksystem (P.A.S.T) zur Verarbeitung und Interpretation von palynologischen Daten aus dem Paläogen Mitteleuropas mit Diversitätsbetrachtungen / A data base system (P.A.S.T) for processing and interpreting palynological data from the Palaeogene of Central Europe - application to diversity studies

Bode, Thomas 12 December 2001 (has links)
No description available.
97

Magmatic Evolution of the Eocene Volcanic Rocks of the Bijgerd Kuh E Kharchin Area, Uromieh-Dokhtar Zone, Iran

Davarpanah, Armita 13 July 2009 (has links)
Composition and texture of the Middle and Late Eocene volcanic, volcaniclastic, and volcanic-sedimentary rocks in the Bijgerd-Kuh e Kharchin area, in the Uromieh-Dokhtar zone northwest of Saveh, Iran, suggest the complexity of the magmatic system that involved multiple eruptions from one or more sources. Hydrated volcanic fragments in hyaloclastic rocks, and the presence of a sequence of shallow and intermediate-depth marine microfossils, suggest that the Middle Eocene units were erupted in a marine basin. The bimodal volcanism of the Late Eocene is distinguished by the presence of four alternating sequences of hyaloclastite lava and ignimbrite. The REE patterns show spatial homogeneity and temporal heterogeneity in the composition of all the Late Eocene sequences, suggesting origination of magma from varying sources that erupted at different times. The trace element distributions of the hyaloclastites and ignimbrites are compatible with those evolved through fractional crystallization of the lower and upper continental crust, respectively.
98

Facies Architecture and Stratigraphy of Tidal Ridges in the Eocene Roda Formation, Northern Spain

Michaud, Kain 02 May 2011 (has links)
ABSTRACT The Eocene Roda Formation in northern Spain documents the deposits from a range of coastal depositional environments. These include alluvial plains, distributary channels, mouth bars, upper to lower-shorefaces, and tidal shelf ridges. Eighteen progradational sand tongues that are interpreted as parasequences compose two third-order sequences. Sequence 1 accumulated in an environment with strong tidal currents and high rates of progradation, while Sequence 2 was deposited under relatively weaker currents and higher rates of aggradation, which produced a higher mudstone:sandstone ratio. The stratigraphy highlights the transgressive origin of six tidal shelf ridges, three in each sequence, that overlie regressive deltaic tongues. Sequence 1 shelf ridges are composed almost entirely of cross-bedded sandstones, whereas Sequence 2 ridges are composed of a mixture of cross-bedded and ripple-laminated deposits. Ridges in both sequences contain bioturbation that is typical of the Cruziana Ichnofacies, and that indicates a marine origin. The tidal ridges are stratigraphically located at or near the point of maximum third-order regression, and are not found within early highstand or late transgressive deposits― times of high relative sea level when the deltaic shoreline did not protrude significantly. Tidal currents were accentuated at the coast when the delta complex had prograded several kilometres into the basin, while during times of high relative sea level, the basin was wider and tidal currents were weaker, consequently leading to a lack of tidal deposits. The tidal ridges are, thus, interpreted as being headland-associated deposits. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2011-04-29 17:10:10.008
99

Sedimentological and ichnological characteristics of Dur At Tallah siliciclastic rock sequence, and their significance in the depositional environment interpretation of tidal-fluvial system (Upper Eocene, Sirt Basin, Libya)

Abouessa, Ashour 19 December 2013 (has links) (PDF)
Dur At Talah sedimentary sequence, located at the southern side of the Sirt Basin in central Libya, is composed of 150 m thick of mainly siliciclastic rocks. The importance of this sequence is linked to the importance of the Sirt Basin as one of large hydrocarbon reservoirs in Libya. The sequence is also an excellent site for vertebrate fossils of Late Eocene, the age of the sequence. Previous studies, though very limited compared to the importance of this area, are focused on its paleontological content. Sedimentology received only scant attention before this project. This thesis is an outcrop based study in which the focus is given to the sedimentary and biogenic (trace fossils) structures, aiming at defining and interpreting depositional facies which building up the sequence. The study is mainly based on field data which are analyzed on the light of related published literature and on the comparison with modern sedimentary environments. Results of facies analysis have led to splitting the entire sequence into three genetically related intervals. The oldest, we called the New Idam Unit (around 80m), is composed of very fine sandstones to mudstones. New Idam Unit is unconformably overlain by the Sarir Unit (around 50m), composed of medium grained cross bedded sandstones (the lower 25-30 m) changes up to very coarse and microconglomeratic sandstone (the upper 20-30 m). Thus, the Sarir Unit is split into the lower Sarir Subunit and upper Sarir subunit. The New Idam Unit presents both classical and unusual sedimentary and biogenic indicators that attribute this unit to estuarine depositional environment. It starts with outer estuarine (the lower 35 m) and ends up with inner estuarine (the upper 45 m). Maximum flooding surface is located in between. Above this surface the fluvial indicators increase and tidal indicators decrease, thus providing clue for basinward (North) migration of the shoreline. The lower Sarir subunit which was previously interpreted as fluvial deposits, preserves multi-scale sedimentary structures that undoubtedly belong to tidal processes. This is especially evidenced at the lower part of the lower Sarir Subunit (LLS). Fluvial indications over dominates the tidal ones in the upper part of the lower Sarir (ULS). Due to this configuration the whole lower Sarir subunit is interpreted as shallow marine, deltaic, depositional system, occurred during sea level ¨normal¨ regression. This time, maximum flooding surface is located between the LLS and ULS. The lower Sarir subunit is terminated by subaerial unconformity, with evidences of subaerial exposure preserved at the top of the ULS. These are intruded by the upper Sarir subunit which presents clear evidences of strictly fluvial environment of deposition. The deposits of the upper Sarir subunit record the low stand system tract part of the Dur At Talah sequence. In addition to the outlined results, the sequential pattern of the depositional events is suggested for the entire sequence of Dur At Talah. This study provides a valuable information regarding the depositional and sequential aspects of the Sirt Basin during the late Eocene, it also provide an unique case study for the better understanding of the shallow marine tidal deposits.
100

Changes in the abundance and diversity of the Proteaceae over the Cainozoic in south-western Australia

Itzstein-Davey, Freea January 2003 (has links)
South-western Australia is a globally significant hotspot of plant species diversity, with high endemism and many rare plant species. Proteaceae is a major component of the south-western flora, though little is known about how its diversity developed. This prompted the present study to investigate changes in the abundance and diversity of Proteaceae, in south-western Australia, by concurrently studying three sediment sequences of different ages over the Cainozoic and a modern pollen rain study. Modern pollen-vegetation relationships in the two Proteaceae species rich nodes of the northern and southern sandplains were quantified. It was found that Proteaceous genera can contribute up to 50% of the total pollen rain. Banksia/Dryandra pollen was the most abundant with Isopogon, Petrophile and Lambertia also commonly noted. The vegetation and environmental setting during three pivotal periods of the Cainozoic: Holocene, Pliocene and Eocene, were investigated. Eocene sediment from Lake Lefroy confirmed the presence of a Nothofagus dominated rainforest in the Middle to Late Eocene. At this time Proteaceae species were at least as diverse as today, if not more so, contributing up to a maximum of 42% of the total pollen rain. Taxa recorded included: Banksieaeidites arcuatus, Propylipollis biporus, Proteacidites confragosus, Proteacidites crassus, Proteacidites nasus and Proteacidites pachypolus. Several taxa remain undescribed and unnamed. This study also identified that Proteaceae pollen representation varies across small lateral distances. Thus as samples varied spatially and temporally, single core samples are not sufficient to identify spatial patterns in Proteaceae or other low pollen producing taxa. Some 7.91 cm of laminated Pliocene sediment from Yallalie, south-western Australia, was also examined. It covers 84 years of record and confirmed other regional reports that south-western Australia was covered by a rich vegetation mosaic consisting of heathy and wet rainforest elements. Although Proteaceae species were a consistent component of the pollen counts, diversity and abundance (maximum of 5%) was low throughout the studied section. Banksia/Dryandra types were most commonly noted. A 2 m core was retrieved from Two Mile Lake, near the Stirling Ranges and provided an early Holocene vegetation history. Geochemical and palynological evidence recorded little change, suggesting the environment of deposition was relatively uniform. Proteaceae species were noted throughout the core, though in low numbers, at a maximum of 3.5 % of the total pollen rain. Banksia/Dryandra was the most abundant while Isopogon, Lambertia, Petrophile and Franklandia were also noted. A regression model was developed through the modern pollen rain study to predict the number of Proteaceae in the vegetation. This was also applied to the fossil pollen records. The estimated number of Proteaceae species in the Eocene suggests a maximum of 20 and a minimum of 10 taxa. For the Pliocene record, an estimated 7 - 9 species was found and for the Holocene pollen, between 7 - 8 were present. Thus the Eocene was similar in Proteaceae diversity to today. The results from the Pliocene and Holocene suggest that Proteaceae diversity was lower than today. Findings of this research indicate that Proteaceae species are an important and consistent component of vegetation in south-western Australia over the Cainozoic. It is likely that both changing pollination mechanisms and changes in associated vegetation are important in the determining the dispersal of Proteaceaous pollen. By understanding how the vegetation has changed and developed in south-western Australia, present vegetation can be managed to include intra-specific variation and ensure the majority of species are conserved for present and future generations to enjoy.

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