Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/44/44141/tde-29012024-104545/ |
Resumo: | The Amazonia biome hosts upland closed and open vegetation ecosystems, in which the current biogeographical patterns are intricately linked to changes of the physical landscape. Open vegetation ecosystems, especially white-sand ecosystems (WSE) and savannas, have long been thought as key environments of biotic diversification in Amazonia. Understanding the origin, resilience and dynamics of the substrates supporting different ecosystems is indispensable for better comprehension of Amazonian biogeography. Here we investigate the spatial distribution of Amazonian open vegetation ecosystems and their physical landscape, represented relief and type and age of geological substrates. To achieve this aim, we selected sandy substrates areas in central and eastern Amazonia, which were characterized through the application of (i) optically stimulated luminescence (OSL) and thermally transferred (TT) OSL dating, (ii) OSL and thermoluminescence (TL) sensitivity analyses as sedimentary history tracer, (iii) textural and compositional analyses (i.e., grain size, X-ray fluorescence (XRF) and magnetic susceptibility), combined with (iv) a comprehensive review on the substrate origins of different open vegetation ecosystems across Amazonia. Open vegetation ecosystems in Amazonia can be divided as occurring in highland or lowland areas. In the highlands, long-term exhumation and weathering of pre-Cenozoic rocks render more stable upland areas over time. Whereas in lowland Amazonia, the rapidly changing landscape due to the fluvial and eolian systems dynamics can expand or retract sandy substrates and their overlying open vegetation more frequently. The widespread occurrence of savannas and WSE upon the extensive sandy alluvial plains in Negro and Branco Rivers basins are associated to high permeability and repeated rising and falling of the water table, favoring the development of spodosols in that area. These sandy substrates present luminescence ages ranging from almost 2 Ma to 0.9 ka. These ages are discussed in terms of potential geomorphic processes leading to the formation of substrates (solar resetting by soil mixing processes and surface transport or apparent age of the parent bedrock). TT-OSL ages ranging from 2 Ma to 23 ka were primarily interpreted as depositional ages of fluvial sediments, which formed upland terraces after channel incision. OSL ages ranging from 68 ka to 0.9 ka can be interpreted as sedimentation ages or solar resetting by soil processes. OSL equivalent dose distributions with high overdispersion, and overall constancy in grain size statistics, BOSL and TL sensitivities and Zr/Ti and Zr content suggest homogenization of sandy substrates via soil mixing processes. In this case, luminescence ages would represent minimum dates for sandy substrate development. However, the possibility of such ages representing the time of sand deposition cannot be ruled out. The coupling between OSL and TT-OSL dating techniques allow us to date sedimentary deposits covering the whole Quaternary, which implies a new time window for the Amazonia history. The availability of sandy substrates supporting open vegetation ecosystems change in multiple spatiotemporal scales, and depends on local conditions, such as water table depth, surface elevation and primary sediment grain size, which can lead to decoupling between regional climate patterns and spatial distribution of open vegetation ecosystems. Thus, the development of sandy substrates would rely on local geological controls, favoring open vegetation ecosystems with fragmented spatial distribution and varied temporal persistence. |
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Origin and chronology of sandy substrates supporting open vegetation ecosystems in AmazoniaOrigem e cronologia dos substratos arenosos de ecossistemas de vegetação aberta na AmazôniaAmazonia sandy terrainsDatação por luminescênciaDepósitos fluviaisEcossistemas de vegetação abertaEvolução da paisagemFluvial depositsLandscape evolutionLuminescence datingOpen vegetation ecosystemsTerrenos arenosos da AmazôniaThe Amazonia biome hosts upland closed and open vegetation ecosystems, in which the current biogeographical patterns are intricately linked to changes of the physical landscape. Open vegetation ecosystems, especially white-sand ecosystems (WSE) and savannas, have long been thought as key environments of biotic diversification in Amazonia. Understanding the origin, resilience and dynamics of the substrates supporting different ecosystems is indispensable for better comprehension of Amazonian biogeography. Here we investigate the spatial distribution of Amazonian open vegetation ecosystems and their physical landscape, represented relief and type and age of geological substrates. To achieve this aim, we selected sandy substrates areas in central and eastern Amazonia, which were characterized through the application of (i) optically stimulated luminescence (OSL) and thermally transferred (TT) OSL dating, (ii) OSL and thermoluminescence (TL) sensitivity analyses as sedimentary history tracer, (iii) textural and compositional analyses (i.e., grain size, X-ray fluorescence (XRF) and magnetic susceptibility), combined with (iv) a comprehensive review on the substrate origins of different open vegetation ecosystems across Amazonia. Open vegetation ecosystems in Amazonia can be divided as occurring in highland or lowland areas. In the highlands, long-term exhumation and weathering of pre-Cenozoic rocks render more stable upland areas over time. Whereas in lowland Amazonia, the rapidly changing landscape due to the fluvial and eolian systems dynamics can expand or retract sandy substrates and their overlying open vegetation more frequently. The widespread occurrence of savannas and WSE upon the extensive sandy alluvial plains in Negro and Branco Rivers basins are associated to high permeability and repeated rising and falling of the water table, favoring the development of spodosols in that area. These sandy substrates present luminescence ages ranging from almost 2 Ma to 0.9 ka. These ages are discussed in terms of potential geomorphic processes leading to the formation of substrates (solar resetting by soil mixing processes and surface transport or apparent age of the parent bedrock). TT-OSL ages ranging from 2 Ma to 23 ka were primarily interpreted as depositional ages of fluvial sediments, which formed upland terraces after channel incision. OSL ages ranging from 68 ka to 0.9 ka can be interpreted as sedimentation ages or solar resetting by soil processes. OSL equivalent dose distributions with high overdispersion, and overall constancy in grain size statistics, BOSL and TL sensitivities and Zr/Ti and Zr content suggest homogenization of sandy substrates via soil mixing processes. In this case, luminescence ages would represent minimum dates for sandy substrate development. However, the possibility of such ages representing the time of sand deposition cannot be ruled out. The coupling between OSL and TT-OSL dating techniques allow us to date sedimentary deposits covering the whole Quaternary, which implies a new time window for the Amazonia history. The availability of sandy substrates supporting open vegetation ecosystems change in multiple spatiotemporal scales, and depends on local conditions, such as water table depth, surface elevation and primary sediment grain size, which can lead to decoupling between regional climate patterns and spatial distribution of open vegetation ecosystems. Thus, the development of sandy substrates would rely on local geological controls, favoring open vegetation ecosystems with fragmented spatial distribution and varied temporal persistence.O bioma amazônico abriga tanto ecossistemas de vegetação fechada quanto aberta, em que os padrões biogeográficos atuais se relacionam intimamente a mudanças da paisagem física da área. Ecossistemas de vegetação aberta, especialmente os ecossistemas de areia branca (EAB) e as savanas, são considerados como ambientes chave para a diversificação biótica na Amazônia. Entender a origem, resiliência e dinâmica dos substratos que suportam os diferentes ecossistemas é indispensável para melhor compreensão da biogeografia amazônica. Nesta tese, investigamos a distribuição dos ecossistemas de vegetação aberta da Amazônia e as características de sua paisagem física, representadas pelo relevo e tipo e idade do substrato geológico. Para tanto, foram selecionados substratos arenosos na Amazônia central e leste, que foram caracterizados através da aplicação de (i) datação por luminescência opticamente estimulada (LOE ou OSL na sigla em inglês) e LOE termalmente transferida (TT-OSL na sigla em inglês), (ii) análises de sensibilidade LOE e de termoluminescência (TL) como traçadores da história sedimentar dos depósitos, (iii) análises texturais e composicionais (i.e. granulometria, fluorescência de raios-X (FRX) e susceptibilidade magnética), combinados com uma revisão extensiva da literatura sobre a origem dos diferentes substratos de diferentes ecossistemas de vegetação aberta espalhados pela Amazônia. Os ecossistemas de vegetação aberta na Amazônia podem ser divididos entre os que ocorrem nas áreas altas e aqueles nas áreas baixas. Nas áreas altas, os processos mais longos de exumação e intemperismo de rochas pré-Cenozoicas criam áreas de terra firme mais estáveis ao longo do tempo. Já nas áreas baixas da Amazônia, a mudança rápida na paisagem devido à dinâmica dos sistemas fluviais e eólicos cria condições para que os ecossistemas de vegetação aberta possam expandir ou retrair mais rapidamente. A maior ocorrência de savanas e EAB sobre as planícies aluviais arenosas nas bacias dos rios Negro e Branco é associada à alta permeabilidade dos substratos e à subida e descida repetida do nível dágua, que favorece a formação de espodossolos nessa área. Tais substratos arenosos apresentam idades de luminescência variando de 2 Ma até 0.9 ka. Estas idades são discutidas em termos dos processos geomórficos potenciais que formaram os substratos (fotoesvaziamento devido à processos de mistura de solo ou transporte de grãos em superfície ou idade aparente do substrato rochoso fonte). As idades TT-OSL (variando de 2 Ma até 23 ka) foram interpretadas primariamente como idades deposicionais de terraços fluviais após incisão. As idades OSL (variando de 68 a 0.9 ka) podem ser interpretadas tanto como idades deposicionais quanto fotoesvaziamento por processos de mistura do solo. A distribuição larga dos valores de doses equivalentes OSL e a consistência nas estatísticas de 8 tamanho de grão, sensibilidade OSL e TL e conteúdo de Zr/Ti e Zr sugere homogeneização por mistura do solo. Entretanto, a possibilidade de tais idades indicarem o momento de deposição não pode ser descartada. A associação das técnicas de datação OSL e TT-OSL permite a datação de depósitos sedimentares abrangendo todo o período do Quaternário, o que implica em uma nova janela de tempo para a história da Amazônia. A disponibilidade de substratos arenosos que suportam ecossistemas de vegetação aberta muda em múltiplas escalas espaço-temporais, e depende de condições locais, como nível dágua, elevação e tamanho de grão, o que pode gerar uma dissociação entre os padrões de clima regional e a distribuição espacial dos ecossistemas de vegetação aberta. Assim, o desenvolvimento dos substratos arenosos dependeria de controles geológicos locais, favorecendo a fragmentação espacial e variada resiliência temporal dos ecossistemas de vegetação aberta.Biblioteca Digitais de Teses e Dissertações da USPSawakuchi, Andre OliveiraRodrigues, Fernanda Costa Gonçalves2022-09-20info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/44/44141/tde-29012024-104545/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPReter o conteúdo por motivos de patente, publicação e/ou direitos autoriais.info:eu-repo/semantics/openAccesseng2024-01-29T16:04:02Zoai:teses.usp.br:tde-29012024-104545Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212024-01-29T16:04:02Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia Origem e cronologia dos substratos arenosos de ecossistemas de vegetação aberta na Amazônia |
title |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
spellingShingle |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia Rodrigues, Fernanda Costa Gonçalves Amazonia sandy terrains Datação por luminescência Depósitos fluviais Ecossistemas de vegetação aberta Evolução da paisagem Fluvial deposits Landscape evolution Luminescence dating Open vegetation ecosystems Terrenos arenosos da Amazônia |
title_short |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
title_full |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
title_fullStr |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
title_full_unstemmed |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
title_sort |
Origin and chronology of sandy substrates supporting open vegetation ecosystems in Amazonia |
author |
Rodrigues, Fernanda Costa Gonçalves |
author_facet |
Rodrigues, Fernanda Costa Gonçalves |
author_role |
author |
dc.contributor.none.fl_str_mv |
Sawakuchi, Andre Oliveira |
dc.contributor.author.fl_str_mv |
Rodrigues, Fernanda Costa Gonçalves |
dc.subject.por.fl_str_mv |
Amazonia sandy terrains Datação por luminescência Depósitos fluviais Ecossistemas de vegetação aberta Evolução da paisagem Fluvial deposits Landscape evolution Luminescence dating Open vegetation ecosystems Terrenos arenosos da Amazônia |
topic |
Amazonia sandy terrains Datação por luminescência Depósitos fluviais Ecossistemas de vegetação aberta Evolução da paisagem Fluvial deposits Landscape evolution Luminescence dating Open vegetation ecosystems Terrenos arenosos da Amazônia |
description |
The Amazonia biome hosts upland closed and open vegetation ecosystems, in which the current biogeographical patterns are intricately linked to changes of the physical landscape. Open vegetation ecosystems, especially white-sand ecosystems (WSE) and savannas, have long been thought as key environments of biotic diversification in Amazonia. Understanding the origin, resilience and dynamics of the substrates supporting different ecosystems is indispensable for better comprehension of Amazonian biogeography. Here we investigate the spatial distribution of Amazonian open vegetation ecosystems and their physical landscape, represented relief and type and age of geological substrates. To achieve this aim, we selected sandy substrates areas in central and eastern Amazonia, which were characterized through the application of (i) optically stimulated luminescence (OSL) and thermally transferred (TT) OSL dating, (ii) OSL and thermoluminescence (TL) sensitivity analyses as sedimentary history tracer, (iii) textural and compositional analyses (i.e., grain size, X-ray fluorescence (XRF) and magnetic susceptibility), combined with (iv) a comprehensive review on the substrate origins of different open vegetation ecosystems across Amazonia. Open vegetation ecosystems in Amazonia can be divided as occurring in highland or lowland areas. In the highlands, long-term exhumation and weathering of pre-Cenozoic rocks render more stable upland areas over time. Whereas in lowland Amazonia, the rapidly changing landscape due to the fluvial and eolian systems dynamics can expand or retract sandy substrates and their overlying open vegetation more frequently. The widespread occurrence of savannas and WSE upon the extensive sandy alluvial plains in Negro and Branco Rivers basins are associated to high permeability and repeated rising and falling of the water table, favoring the development of spodosols in that area. These sandy substrates present luminescence ages ranging from almost 2 Ma to 0.9 ka. These ages are discussed in terms of potential geomorphic processes leading to the formation of substrates (solar resetting by soil mixing processes and surface transport or apparent age of the parent bedrock). TT-OSL ages ranging from 2 Ma to 23 ka were primarily interpreted as depositional ages of fluvial sediments, which formed upland terraces after channel incision. OSL ages ranging from 68 ka to 0.9 ka can be interpreted as sedimentation ages or solar resetting by soil processes. OSL equivalent dose distributions with high overdispersion, and overall constancy in grain size statistics, BOSL and TL sensitivities and Zr/Ti and Zr content suggest homogenization of sandy substrates via soil mixing processes. In this case, luminescence ages would represent minimum dates for sandy substrate development. However, the possibility of such ages representing the time of sand deposition cannot be ruled out. The coupling between OSL and TT-OSL dating techniques allow us to date sedimentary deposits covering the whole Quaternary, which implies a new time window for the Amazonia history. The availability of sandy substrates supporting open vegetation ecosystems change in multiple spatiotemporal scales, and depends on local conditions, such as water table depth, surface elevation and primary sediment grain size, which can lead to decoupling between regional climate patterns and spatial distribution of open vegetation ecosystems. Thus, the development of sandy substrates would rely on local geological controls, favoring open vegetation ecosystems with fragmented spatial distribution and varied temporal persistence. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-09-20 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/44/44141/tde-29012024-104545/ |
url |
https://www.teses.usp.br/teses/disponiveis/44/44141/tde-29012024-104545/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Reter o conteúdo por motivos de patente, publicação e/ou direitos autoriais. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Reter o conteúdo por motivos de patente, publicação e/ou direitos autoriais. |
eu_rights_str_mv |
openAccess |
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application/pdf |
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|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
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USP |
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USP |
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Biblioteca Digital de Teses e Dissertações da USP |
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Biblioteca Digital de Teses e Dissertações da USP |
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Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
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1809091166387306496 |