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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.
41

Projeto arqueológico Alto Canoas - Paraca: um estudo da presença Jê no planalto Catarinense. / Upper Canoas Archaeological Project: A study of the Jê presence in the plateau of Santa Catarina, Brazil

Rafael Corteletti 05 March 2013 (has links)
Nesta tese vou apresentar novos dados sobre padrões de ocupação dos Jê Meridionais e minhas interpretações sobre a história deste povo, com base em meu estudo de caso, do Alto Rio Canoas, região de Urubici, em Santa Catarina, Brasil. No planalto, os camposde altitude e a mata de araucária dominam a paisagem. Nas serrarias de Urubici, as nascentes de vários arroios e rios começam em zonas húmidas, com solos rasos e pedregosos, na área dos campos, a cerca de 1800m de altitude. Estas águas correm através de vales incisos florestados pela mata de araucária criando cachoeiras e corredeiras, que acabam por se transformar no meândrico Rio Canoas, que flui no meio de um vale largo e plano, em torno de 1000m acima do nível do mar. A montanhosa região de Urubici foi intensamente pesquisada na década de 60, mas depois disso, a pesquisa ficou estagnada. Os principais pontos deste projeto foram: Primeiro, foram revisadas e atualizadas as pesquisas anteriores, revisitando a maioria dos sítios arqueológicos mapeados na década de 60, atribuindo-lhes coordenadas geográficas, fotos e mapas, e descrições ambientais recentes. Segundo, além da visita aos sítios mapeados previamente, foi realizado um mapeamento oportunista de novos sítios, baseado em entrevistas com membros da comunidade local, o que gerou um novo mapa arqueológico da região. Terceiro, com base nessas informações e nas novas escavações em sítios específicos, iniciou-se a reflexão sobre as paisagens Jê do Sul, com o objetivo de compreender a história de longo prazo e o sistema de assentamento da tradição arqueológica Taquara-Itararé. Quarto, a partir das análises de grãos de amido de fitólitos, a partir de restos carbonizados de alimento aderidos a parede da cerâmica coletada na escavação do sítio Bonin, foram obtidos novos dados, importantíssimos para pensar novas formas de interpretação na arqueologia da tradição Taquara-Itararé. Tais análises trouxeram evidências de produção de alimentos como Zea mays, Cucurbitasp., Manihotsp., e o consumo alimentar de Phaseolussp. e Dioscoreasp. entre outros, o que, sem dúvida, é uma chave para pensar em outro tipo de organização social, mobilidade e economia para os povos proto-Jê Meridional. Em quinto lugar, no sentido de pensar uma \"estratigrafia paisagem do Jê Meridional\" um banco de dados SIG foi utilizado como uma ferramenta para criar modelos virtuais de, por exemplo, a análise visibilidade acumulada entre sítios e análise de rotas de menor custo. / In this thesis I will present new data on Southern Jêsettlement patterns, and my interpretations regarding the history of these people, based on my case study, from the Upper Canoas River, Urubici region, in Santa Catarina state, Brazil. On the highland plateau, the High Altitude Grasslands (or Campos) and the Paraná Pine Forest dominate the landscape. In the Urubici hills, various headwaters begin in wetland areas, with shallow and rocky soils, on Campos, around 1800m altitude. These waters flow through incised valleys forested by Paraná Pine and create waterfalls and rapids, which eventually turn into the meandering Canoas River that flows in the middle of a wide and flat valley, around 1000m above sea level. The mountainous Urubici region was intensively researched in the 60\'s, but after that, research wasstagnated. The main points of this project were: First, I reviewed and updated previous research, which involved relocating the sites mapped in the 60\'s, assigning them geographical coordinates, photos and maps, and improving environmental descriptions. Second, I carried out an inspection of previously recorded sites and carried out opportunistic survey, based on interviews with members of the local community, looking for new sites, and making a new archaeological map of the region. Third, based on this information and my new excavations at targeted sites, I aimed to think about the Southern Jê landscapes, with a view to understanding the long-term history and the settlement pattern of the Taquara-Itararé archaeological tradition. Fourth, starch grain and phytoliths analysis from charred food remains founded in pottery, collected at Bonin site excavation, achieved important new data for new interpretive ways on Taquara-Itararé archaeology, bringing to us food production evidences of Zea mays, Cucurbitasp., Manihotsp., and food consumption of Phaseolussp.,Dioscoreasp. and others, what is a key to think another kind of social organization, mobility and economy for southern proto-Jê people. Fifth, in a way to think the \"southern Jê landscape stratigraphy\" aGIS database were used like a tool to create virtual models of, for example, cumulative viewshed analysis and least coast pathway analysis.
42

Environmental history in southern Mozambique : Reconstruction of flooding events, hydroclimate and sea-level dynamics since mid-Holocene

Raúl Sitoe, Sandra January 2017 (has links)
The aim of this thesis has been to reconstruct paleoenvironment, paleohydrology and paleoclimate in coastal southern Mozambique, with emphasis on tracing past flooding events on the lower Limpopo River floodplain. In order to extend flood chronologies beyond periods covered by instrumental data, sediments from lakes on the floodplain were studied (Lake Lungué, Coassane Oxbow, Lake Magandane and Lake Soane). Past sea-level variations and climate changes were deduced by analyzing sediments from coastal sites north of the floodplain area (Lake Chilau, Lake Nhauhache and Macassa Bay). To achieve the established objectives, a multi-proxy approach was applied on most of the retrieved sediment cores, involving analysis of mineral magnetic parameters, grain-size and organic carbon in combination with analysis of microfossils such as diatoms and/or phytoliths. Chronologies for the constructed time-series analysis were obtained by radiocarbon dating and age-depth modelling. The synthesized data from the sampled sites on the Limpopo River floodplain suggest that the area was affected by at least 16 flooding events of variable magnitudes during the studied period. These are dated to c. AD 940, 980, 1040, 1100, 1250, 1300, 1370, 1580, 1665, 1730, 1755, 1855, 1920, 1945, 1970 and 2000. In calibrated years BP these ages correspond to 1010, 970, 910, 850, 700, 650, 580, 370, 285, 220, 195, 95, 30, and 5 cal yrs BP. The two youngest are dated to 20 and 50 years AP (After Present being 1950). Proxy data further suggest that southern Africa was subject to two periods of sea-level highstands, at c. 5000–4200 BC (6950–6150 cal yrs BP) and AD 300–950 (1650–1000 cal yrs BP). The former represents the middle part of the postglacial climatic optimum. The wettest period in the Limpopo River floodplain was reported between AD 1360 and 1560 (590 and 390 cal yrs BP) in the Lake Lungué record, while Lake Chilau experienced wet conditions between AD 1200 and 1400 (750 and 550 cal yrs BP), then returning to drier conditions that prevailed until c. AD 1600. In Lake Nhauhache, however, drier conditions prevailed from c. AD 1200–1700 (750–250 cal yrs BP), shifting towards wetter at c. AD 1900 (50 cal yrs BP). The deviating signals between records can partly be explained by Lake Lungué basin being located on the Limpopo River floodplain, responding to flooding events associated with precipitation upstream the drainage area. Therefore, wet and dry periods in floodplain lakes (e.g. Lake Lungué) are not expected to correlate with precipitation changes on a local scale, as indicated by e.g. Lake Nhauhache. This is supported by a relatively weak agreement between Lake Lungué record and other nearby records (outside the floodplain), but a better correlation with records from the upper catchment, where a more regional climate signal is provided of the southern African summer rainfall region. / Denna avhandling behandlar studier av paleomiljöer i södra Mozambique med fokus på översvämningshistorik i Limpopo-flodens nedre lopp. Tidsspannet är mitt- och sen-holocen och inkluderar även klimat och havsnivåvariationer. Följande analysmetoder har applicerats på ett flertal sedimentkärnor för att belysa ovanstående frågeställningar: mineralmagnetiska parameterar, kornstorlek, organiskt kol samt kiselmikrofossil (diatoméeter och fytoliter). Åldrar har bestämts med 14C-metoden.  Analyserna visar att mineralmagnetiska parametrar är lämpliga för att identifiera översvämningar, speciellt magnetisk susceptibilitet och SIRM. Dessa parametrar visar på ett sediments magnetiska kornstorlerkar och koncentrationen av finkorniga magnetiska mineral. Även kornstorleksanalyser fungerade som ett bra komplement till dessa metoder. Sammantaget har ett minimum av 16 översvämningar registrerats i Limpopo/flodens nedre lopp under de senaste 1100 åren. Särskilt stora översvämningar har daterats till AD 1250 (700 kal år BP), AD 1370 (580 kal år BP), AD 1580 (370 kal år BP), AD 1855 (95 kal år BP), AD 1920 (30 kal år BP), AD 1970 (20 kal år AP) och AD 2000 (50 kal år AP), där AP betyder ”after present”, vilket är 1950. Mindre kraftiga översvämningar har daterats till AD 940 (1010 kal år BP), AD 980 (970 kal år BP), AD 1040 (910 kal år BP), AD 1100 (850 kal år BP), AD 1300 (650 kal år BP), AD 1665 (285 kal år BP), AD 1730 (220 kal år BP), AD 1755 (195 kal år BP) och AD 1945 (5 kal år BP). Skriftliga källor visar på att åtminstone åtta översvämningar har ägt rum under de senaste 62 åren. Under samma period har denna undersökning registrerat två händelser, vilket indikerar att endast ett fåtal har registrerats med ovan nämnda metoder. Det är sannolikt att sedimentationsmönstret under en översvämning är komplicerat och inte heller likartad från gång till gång. Detta innebär att ett flertal sedimentkärnor behöver analyseras och dateras väl. Ytterligare en försvårande faktor är flodens mycket aktiva meandringsaktivitet. Analys av diatoméer har visats vara värdefulla när det gäller översvämningshistorik, klimatförändringar och havsytevariationer. Sedimenten i den något till flodslättens nedre lopp perifert belägna sjön Lungué indikerar fuktiga förhållanden mellan AD 1360 och 1560 (590 till 390 kal år BP). Kombinerade fytolit- och diatoméanalyser av sedimenten i sjön Chilau indikerar fuktiga förhållanden från AD 1200 till 1400 (750 till 550 kal år BP), varefter torrare förhållanden rådde till ca AD 1600 (350 kal år BP). Diatoméanalys av sedimenten i sjön Nhauhache indikerar generellt sett torrare förhållanden mellan AD 1200 och AD 1700 (750 till 250 kal år BP) då klimatet blev fuktigare. De fuktiga och torra förhållanden som dokumenterats i sjön Lungué och översvämningshistoriken korrelerar inte helt med lokala nederbördsförhållanden. Däremot stämmer erhållna data bättre med förhållanden i den övre delen av Limpopoflodens dräneringsområde. Även sjöar och fyllda meanderbågar på själva flodslätten verkar reagera tydligare på översvämningar orsakade av nederbörd i den övre delen av flodloppet. Undersökningen indikerar två faser av en förhöjd havsyta längs kusten i södra Mozambique. En äldre fas är daterad till ca 5000–4200 f.Kr. (6950–6150 kal år BP), vilken representerar den mellersta delen av det postglaciala värmeoptimet. Denna tolkning stöds även av andra undersökningar. En yngre fas har daterats till AD 300–950 (1650–1000 kal år BP), vilken korresponderar till en period med något förhöjda temperaturer i ett globalt perspektiv. / O presente projecto teve como objectivo a reconstrução do paleoambiente, paleohidrologia e paleoclima da costa Sul de Moçambique, com ênfase na identificação de vestígios de eventos de cheias que tenham, no passado, afectado a planície de inundação do Rio Limpopo, com vista a fazer a extensão das datações de cheias para o período anterior aos instrumentos de medição. Deste modo, foram estudados sedimentos recuperados através de testemunhos de sondagem em lagos dentro da planície de inundação (Lago Magandane, Lago Lungué, Lago Soane e o canal abandonado Coassane). As variações do nível do mar e mudanças climáticas do passado foram deduzidas a partir da análise de sedimentos de áreas costeiras a norte da planície de inundação (Lago Chilau, Lago Nhauhache e a Baía de Macassa). Para o alcance destes objectivos, os sedimentos dos testemunhos de sondagem recuperados foram submetidos a várias análises laboratoriais que incluem propriedades de minerais magnéticos, granulometria, teor de matéria orgânica e de microfósseis (diatomáceas e fitólitos). Para o estabelecimento do modelo cronológico foram usadas datações pelo método 14C feitas em matéria orgânica, assim como conchas de gastrópodes e bivalves. A combinação dos resultados obtidos para os pontos de amostragem localizados dentro da planície de inundação do Rio Limpopo, sugerem que esta área foi afectada por um mínimo de 16 eventos de cheias de variada magnitude nos últimos 1100 anos. As cheias de alta magnitude tiveram lugar nos anos 1250, 1370, 1580, 1855, 1920, 1970 e 2000. Por seu turno, as cheias de magnitude moderada ocorrerram nos anos 940, 980, 1040, 1100, 1300, 1665, 1730, 1755 e 1945.. Os anos a negrito são indicativos de eventos de cheias de alta magnitude. O número total de eventos identificados no presente estudo é um mínimo que poderá ter afectado a planície de inundação, tendo em consideração que fontes escritas reportam a ocorrência de pelo menos oito eventos nos últimos 62 anos, tendo o presente estudo revelado somente dois. Isto indica que apenas eventos de cheias intensos podem ser revelados pelos métodos aplicados nesta investigação. Adicionalmente, este estudo mostra a necessidade de aumentar o número de pontos de amostragem para permitir a identificação de mais eventos de cheias ocorridos no passado, devido à diferenciada resposta sedimentológica e geomagnética às cheias, a qual se encontra directamente relacionada à distância do rio meandrante. As análises de microfósseis de diatomáceas permitiram reconstruir o paleoclima e as influências do nível do mar nas áreas de estudo deste projecto. Os registros de diatomáceas do Lago Lungué indicam um período húmido entre AD 1360 e 1560. No Lago Chilau, dados de diatomáceas e fitólitos sugerem condições de humidade entre AD 1200 e 1400. Por seu turno, no Lago Nhauhache, condições de seca dominam entre AD 1200 e 1700. As condições de seca e humidade documentadas no Lago Lungué e os eventos de cheias revelados pelos sedimentos analisados da planície de inundação do Rio Limpopo não mostram total correlação com períodos de baixa e alta precipitação a nível local, mas apresentam boa correlação com evidências a montante na área de drenagem do Rio Limpopo. Em geral, lagos activos ou preenchidos por sedimentos mostrarão ser mais susceptíveis a cheias com origem a montante do que a nível local. As investigações conduzidas permitiram identificar dois períodos de alto nível do mar na região sul de Moçambique. A fase mais antiga teve lugar há cerca de 5000–4200 BC (6950–6150 anos do calendário BP), representando a fase mais recente do pós-glaciar climático óptimo (postglacial climatic optimum, PCA). A fase recente é datada de AD 300–950 (1650–1000 anos do calendário BP), correspondendo a um período de temperaturas relativamente altas a nível global. / Climate and Environmental Research
43

Late Quaternary landscape evolution and environmental change in Charwell Basin, South Island, New Zealand

Hughes, Matthew W. January 2008 (has links)
Charwell Basin is a 6 km-wide structural depression situated at the boundary between the axial ranges and faulted and folded Marlborough Fault Zone of north-eastern South Island, New Zealand. The basin contains the piedmont reach of the Charwell River, and a series of late Quaternary loess-mantled alluvial terraces and terrace remnants that have been uplifted and translocated from their sediment source due to strike-slip motion along the Hope Fault which bounds the basin to its immediate north. The aim of this study was to provide an interdisciplinary, integrated and holistic analysis of late Quaternary landscape evolution and environmental change in Charwell Basin using terrain analysis, loess stratigraphy, soil chemistry and paleoecological data. The study contributes new understanding of New Zealand landscape and ecosystem responses to regional and global climatic change extending to Marine Isotope Stage (MIS) 6, and shows that climatically-forced shifts in biogeomorphic processes play a significant role in lowland landscape evolution. Morphometric analysis of alluvial terraces and terrace remnants of increasing age demonstrated geomorphic evolution through time, with a decrease in extent of original planar terrace tread morphology and an increase in frequency of steeper slopes and convexo-concave land elements. Paleotopographic analysis of a >150 ka terrace mantled by up to three loess sheets revealed multiple episodes of alluvial aggradation and degradation and, subsequent to river abandonment, gully incision prior to and coeval with loess accumulation. Spatial heterogeneity in loess sheet preservation showed a complex history of loess accumulation and erosion. A critical profile curvature range of -0.005 to -0.014 (d²z/dx², m⁻¹) for loess erosion derived from a model parameterised in different ways successfully predicted loess occurrence on adjacent slope elements, but incorrectly predicted loess occurrence on an older terrace remnant from which all loess has been eroded. Future analyses incorporating planform curvature, regolith erosivity and other landform parameters may improve identification of thresholds controlling loess occurrence in Charwell Basin and in other South Island landscapes. A loess chronostratigraphic framework was developed for, and pedogenic phases identified in, the three loess sheets mantling the >150 ka terrace. Except for one age, infrared-stimulated luminescence dates from both an upbuilding interfluve loess exposure and colluvial gully infill underestimated loess age with respect to the widespread Kawakawa/Oruanui Tephra (KOT; 27,097 ± 957 cal. yr BP), highlighting the need for improvements in the methodology. Onset of loess sheet 1 accumulation started at ca. 50 ka, with a break at ca. 27 ka corresponding to the extended Last Glacial Maximum (eLGM) interstadial identified elsewhere in New Zealand. Loess accumulation through MIS 3 indicates a regional loess flux, and that glaciation was not a necessary condition for loess generation in South Island. Loess accumulation and local alluvial aggradation are decoupled: the youngest aggradation event only covers ~12 kyr of the period of loess sheet 1 accumulation. Older local aggradation episodes could not be the source because their associated terraces are mantled by loess sheet 1. In the absence of numerical ages, the timing of L2 and L3 accumulation is inferred on the basis of an offshore clastic sediment record. The upbuilding phase of loess sheet 2 occurred in late MIS 5a/MIS 4, and loess sheet 3 accumulated in two phases in MIS 5b and late MIS 6. Biogenic silica data were used to reconstruct broad shifts in vegetation and changes in gully soil saturation status. During interglacial/interstadial periods (MIS 1, early MIS 3, MIS 5) Nothofagus-dominated forest covered the area in association with Microlaena spp grasses. Lowering of treeline altitude during glacial/stadial periods (MIS 2, MIS 3, MIS 5b, late MIS 6) led to reduction in forest cover and a mosaic of shrubs and Chionochloa spp, Festuca spp and Poa spp tussock grasses. Comparison of interfluve and gully records showed spatial heterogeneity in vegetation cover possibly related to environmental gradients of exposure or soil moisture. A post-KOT peak in gully tree phytoliths corresponds to the eLGM interstadial, and a shift to grass-dominated vegetation occurred during the LGM sensu stricto. Diatoms indicated the site became considerably wetter from ca. 36 ka, with peak wetness at ca. 30, 25 and 21 ka, possibly due to reduced evapotranspiration and/or increased precipitation from a combination of strengthened westerly winds and increased cloudiness, or strengthened southerly flow and increased precipitation. Human influence after ca. 750 yr BP led to re-establishment of grassland in the area, which deposited phytoliths mixed to 30 cm depth in the soil. A coupled gully colluvial infilling/vegetation record showed that sediment flux during the late Pleistocene was ~0.0019 m³ m⁻¹ yr⁻¹ under a shrubland/grassland mosaic, and Holocene sediment flux was ~0.0034 m³ m⁻¹ yr⁻¹ under forest. This increase of 60% through the last glacial-interglacial transition resulted from increased bioturbation and down-slope soil transport via root growth and treethrow, which formed a biomantle as evidenced by slope redistribution of the KOT. These results contrast with sediment transport rates and processes hypothesised to occur contemporaneously in adjacent mountain catchments. This suggests that intraregional biogeomorphic processes can differ significantly depending on topography and geological substrate, with different landscapes responding in unique ways to the same climate shifts. Analysis of Quaternary terrestrial landscape evolution in non-glaciated mountainous and lowland areas must therefore consider spatial and temporal heterogeneity in sediment fluxes and underlying transport processes.
44

L’Archaïque récent au Costa Rica, contribution des sites Piedra Viva et Linda Vista à l’histoire culturelle

Messina, Renato 12 1900 (has links)
No description available.
45

Soils and geomorphology of a lowland rimu forest managed for sustainable timber production

Almond, Peter C. January 1997 (has links)
Saltwater Forest is a Dacrydium cupressinum-dominated lowland forest covering 9000 ha in south Westland, South Island, New Zealand. Four thousand hectares is managed for sustainable production of indigenous timber. The aim of this study was to provide an integrated analysis of soils, soil-landform relationships, and soil-vegetation relationships at broad and detailed scales. The broad scale understandings provide a framework in which existing or future studies can be placed and the detailed studies elucidate sources of soil and forest variability. Glacial landforms dominate. They include late Pleistocene lateral, terminal and ablation moraines, and outwash aggradation and degradation terraces. Deposits and landforms from six glacial advances have been recognised ranging from latest Last (Otira) Glaciation to Penultimate (Waimea) Glaciation. The absolute ages of landforms were established by analysis of the thickness and soil stratigraphy of loess coverbeds, augmented with radiocarbon dating and phytolith and pollen analysis. In the prevailing high rainfall of Westland soil formation is rapid. The rate of loess accretion in Saltwater Forest (ca. 30 mm ka⁻¹) has been low enough that soil formation and loess accretion took place contemporaneously. Soils formed in this manner are known as upbuilding soils. The significant difference between upbuilding pedogenesis and pedogenesis in a topdown sense into an existing sediment body is that each subsoil increment of an upbuilding soil has experienced processes of all horizons above. In Saltwater Forest subsoils of upbuilding soils are strongly altered because they have experienced the extremely acid environment of the soil surface at some earlier time. Some soil chronosequence studies in Westland have included upbuilding soils formed in loess as the older members of the sequence. Rates and types of processes inferred from these soils should be reviewed because upbuilding is a different pedogenic pathway to topdown pedogenesis. Landform age and morphology were used as a primary stratification for a study of the soil pattern and nature of soil variability in the 4000 ha production area of Saltwater Forest. The age of landforms (> 14 ka) and rapid soil formation mean that soils are uniformly strongly weathered and leached. Soils include Humic Organic Soils, Perch-gley Podzols, Acid Gley Soils, Allophanic Brown Soils, and Orthic or Pan Podzols. The major influence on the nature of soils is site hydrology which is determined by macroscale features of landforms (slope, relief, drainage density), mesoscale effects related to position on landforms, and microscale influences determined by microtopography and individual tree effects. Much of the soil variability arises at microscales so that it is not possible to map areas of uniform soils at practical map scales. The distribution of soil variability across spatial scales, in relation to the intensity of forest management, dictates that it is most appropriate to map soil complexes with boundaries coinciding with landforms. Disturbance of canopy trees is an important agent in forest dynamics. The frequency of forest disturbance in the production area of Saltwater Forest varies in a systematic way among landforms in accord with changes in abundance of different soils. The frequency of forest turnover is highest on landforms with the greatest abundance of extremely poorly-drained Organic Soils. As the abundance of better-drained soils increases the frequency of forest turnover declines. Changes in turnover frequency are reflected in the mean size and density of canopy trees (Dacrydium cupressinum) among landforms. Terrace and ablation moraine landforms with the greatest abundance of extremely poorly-drained soils have on average the smallest trees growing most densely. The steep lateral moraines, characterised by well drained soils, have fewer, larger trees. The changes manifested at the landform scale are an integration of processes operating over much shorter range as a result of short-range soil variability. The systematic changes in forest structure and turnover frequency among landforms and soils have important implications for sustainable forest management.
46

Soils and geomorphology of a lowland rimu forest managed for sustainable timber production

Almond, Peter C. January 1997 (has links)
Saltwater Forest is a Dacrydium cupressinum-dominated lowland forest covering 9000 ha in south Westland, South Island, New Zealand. Four thousand hectares is managed for sustainable production of indigenous timber. The aim of this study was to provide an integrated analysis of soils, soil-landform relationships, and soil-vegetation relationships at broad and detailed scales. The broad scale understandings provide a framework in which existing or future studies can be placed and the detailed studies elucidate sources of soil and forest variability. Glacial landforms dominate. They include late Pleistocene lateral, terminal and ablation moraines, and outwash aggradation and degradation terraces. Deposits and landforms from six glacial advances have been recognised ranging from latest Last (Otira) Glaciation to Penultimate (Waimea) Glaciation. The absolute ages of landforms were established by analysis of the thickness and soil stratigraphy of loess coverbeds, augmented with radiocarbon dating and phytolith and pollen analysis. In the prevailing high rainfall of Westland soil formation is rapid. The rate of loess accretion in Saltwater Forest (ca. 30 mm ka⁻¹) has been low enough that soil formation and loess accretion took place contemporaneously. Soils formed in this manner are known as upbuilding soils. The significant difference between upbuilding pedogenesis and pedogenesis in a topdown sense into an existing sediment body is that each subsoil increment of an upbuilding soil has experienced processes of all horizons above. In Saltwater Forest subsoils of upbuilding soils are strongly altered because they have experienced the extremely acid environment of the soil surface at some earlier time. Some soil chronosequence studies in Westland have included upbuilding soils formed in loess as the older members of the sequence. Rates and types of processes inferred from these soils should be reviewed because upbuilding is a different pedogenic pathway to topdown pedogenesis. Landform age and morphology were used as a primary stratification for a study of the soil pattern and nature of soil variability in the 4000 ha production area of Saltwater Forest. The age of landforms (> 14 ka) and rapid soil formation mean that soils are uniformly strongly weathered and leached. Soils include Humic Organic Soils, Perch-gley Podzols, Acid Gley Soils, Allophanic Brown Soils, and Orthic or Pan Podzols. The major influence on the nature of soils is site hydrology which is determined by macroscale features of landforms (slope, relief, drainage density), mesoscale effects related to position on landforms, and microscale influences determined by microtopography and individual tree effects. Much of the soil variability arises at microscales so that it is not possible to map areas of uniform soils at practical map scales. The distribution of soil variability across spatial scales, in relation to the intensity of forest management, dictates that it is most appropriate to map soil complexes with boundaries coinciding with landforms. Disturbance of canopy trees is an important agent in forest dynamics. The frequency of forest disturbance in the production area of Saltwater Forest varies in a systematic way among landforms in accord with changes in abundance of different soils. The frequency of forest turnover is highest on landforms with the greatest abundance of extremely poorly-drained Organic Soils. As the abundance of better-drained soils increases the frequency of forest turnover declines. Changes in turnover frequency are reflected in the mean size and density of canopy trees (Dacrydium cupressinum) among landforms. Terrace and ablation moraine landforms with the greatest abundance of extremely poorly-drained soils have on average the smallest trees growing most densely. The steep lateral moraines, characterised by well drained soils, have fewer, larger trees. The changes manifested at the landform scale are an integration of processes operating over much shorter range as a result of short-range soil variability. The systematic changes in forest structure and turnover frequency among landforms and soils have important implications for sustainable forest management.
47

A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western Gulf of Alaska

Wilbur, Cricket C. January 2013 (has links)
No description available.

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