Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene
Autor(a) principal: | |
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Data de Publicação: | 2024 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Repositório Institucional da Universidade Federal Fluminense (RIUFF) |
Texto Completo: | http://app.uff.br/riuff/handle/1/32013 |
Resumo: | The late Miocene - early Pliocene (7.4 - 4.5 Ma) is a key interval in Earth’s history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of the SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ18O and δ13C recorded in the planktonic foraminifera Orbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling the SAFM. Precession cycles governed precipitation from 7.4 to ~6.9 Ma and during the early Pliocene. From ~6.9 to 5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval appear to influence the isotopic records of Orbulina universa imprinting its long-term variability signal as a response to the ocean and atmospheric reorganization. Precession cycles markedly weakened from 5.9 to 5.3 Ma, almost the same period when the Mediterranean Outflow Water ceased. These findings highlight important teleconnections among the SAFM, Mediterranean Sea, and other tropical regions. |
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Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early PlioceneSouthern African MonsoonMessinian salinity crisisOrbital forcingPlioceneMioceneSalinidadeMudança climáticaPaleoclimatologiaGeoquímica ambientalEvolução GeológicaMonção sul africanaCrise de salinidade do messinianoForçante orbitalMiocenoPliocenoThe late Miocene - early Pliocene (7.4 - 4.5 Ma) is a key interval in Earth’s history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of the SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ18O and δ13C recorded in the planktonic foraminifera Orbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling the SAFM. Precession cycles governed precipitation from 7.4 to ~6.9 Ma and during the early Pliocene. From ~6.9 to 5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval appear to influence the isotopic records of Orbulina universa imprinting its long-term variability signal as a response to the ocean and atmospheric reorganization. Precession cycles markedly weakened from 5.9 to 5.3 Ma, almost the same period when the Mediterranean Outflow Water ceased. These findings highlight important teleconnections among the SAFM, Mediterranean Sea, and other tropical regions.Conselho Nacional de Desenvolvimento Científico e TecnológicoO Mioceno tardio - início do Plioceno (7.4 - 4.5 Ma) é um intervalo chave na história da Terra, onde ocorreu uma intensa reorganização da circulação atmosférica e oceânica dentro de um cenário de resfriamento global. A monção sul africana (SAFM) potencialmente desempenhou um papel importante na variabilidade dos sistemas climáticos durante este intervalo. No entanto, a dinâmica desse importante sistema atmosférico é pouco compreendida devido à escassez de registros contínuos. Aqui, apresentamos uma excepcional reconstrução contínua do Mioceno tardio ao início do Plioceno da SAFM com base na geoquímica elementar (razões Ca/Ti e Si/K), geoquímica de isótopos estáveis (δ18O e δ13C registrados nos foraminíferos planctônicos Orbulina universa) e granulometria de sedimentos marinhos do Site U1476 do perfurados durante a Expedição 361 do International Ocean Discovery Program (IODP). Esse site localiza-se na entrada do Canal de Moçambique (oeste do Oceano Índico). As características espectrais da relação Si/K (aporte fluvial) foram usadas para identificar a principal forçante orbital que controlou o SAFM. Os ciclos de precessão governaram a precipitação de 7.4 a ~6,8 Ma e durante o início do Plioceno. De ~6,8 a 5,9 Ma, a precessão e os longos ciclos de excentricidade impulsionaram a SAFM. A maior expansão do manto de gelo antártico neste intervalo parece influenciar os registros isotópicos de Orbulina universa, imprimindo seu sinal de variabilidade de longo prazo como uma resposta ao oceano e à reorganização atmosférica. Os ciclos de precessão enfraqueceram acentuadamente de 5.97 para 5.3 Ma, quase o mesmo período em que o fluxo de água do Mediterrâneo cessou. Essas descobertas destacam importantes teleconexões entre a SAFM, o Mar Mediterrâneo e outras regiões tropicais.99 f.Albuquerque, Ana Luiza Spadanohttp://lattes.cnpq.br/4016720596063058Jiménez-Espejo, Francisco JoséOliveira, Igor Martins Venâncio Padilha dehttp://lattes.cnpq.br/8375137961138590Kochhann, Karlos Guilherme Diemerhttp://lattes.cnpq.br/0122384645987508Jovane, Luigihttp://lattes.cnpq.br/2649740799154948Stríkis, Nicolás Misailidishttp://lattes.cnpq.br/3472432536871948http://lattes.cnpq.br/1520355262876198Azevedo, Allana Queiroz de2024-01-22T19:51:53Z2024-01-22T19:51:53Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfAZEVEDO, Allana Queiroz de. Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene. 2023. 99 f. Tese (Doutorado em Geoquímica - Geoquímica Ambiental) - Universidade Federal Fluminense, Niterói, 2023.http://app.uff.br/riuff/handle/1/32013CC-BY-SAinfo:eu-repo/semantics/openAccessengreponame:Repositório Institucional da Universidade Federal Fluminense (RIUFF)instname:Universidade Federal Fluminense (UFF)instacron:UFF2024-01-22T19:51:58Zoai:app.uff.br:1/32013Repositório InstitucionalPUBhttps://app.uff.br/oai/requestriuff@id.uff.bropendoar:21202024-08-19T11:15:48.934981Repositório Institucional da Universidade Federal Fluminense (RIUFF) - Universidade Federal Fluminense (UFF)false |
dc.title.none.fl_str_mv |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
title |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
spellingShingle |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene Azevedo, Allana Queiroz de Southern African Monsoon Messinian salinity crisis Orbital forcing Pliocene Miocene Salinidade Mudança climática Paleoclimatologia Geoquímica ambiental Evolução Geológica Monção sul africana Crise de salinidade do messiniano Forçante orbital Mioceno Plioceno |
title_short |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
title_full |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
title_fullStr |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
title_full_unstemmed |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
title_sort |
Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene |
author |
Azevedo, Allana Queiroz de |
author_facet |
Azevedo, Allana Queiroz de |
author_role |
author |
dc.contributor.none.fl_str_mv |
Albuquerque, Ana Luiza Spadano http://lattes.cnpq.br/4016720596063058 Jiménez-Espejo, Francisco José Oliveira, Igor Martins Venâncio Padilha de http://lattes.cnpq.br/8375137961138590 Kochhann, Karlos Guilherme Diemer http://lattes.cnpq.br/0122384645987508 Jovane, Luigi http://lattes.cnpq.br/2649740799154948 Stríkis, Nicolás Misailidis http://lattes.cnpq.br/3472432536871948 http://lattes.cnpq.br/1520355262876198 |
dc.contributor.author.fl_str_mv |
Azevedo, Allana Queiroz de |
dc.subject.por.fl_str_mv |
Southern African Monsoon Messinian salinity crisis Orbital forcing Pliocene Miocene Salinidade Mudança climática Paleoclimatologia Geoquímica ambiental Evolução Geológica Monção sul africana Crise de salinidade do messiniano Forçante orbital Mioceno Plioceno |
topic |
Southern African Monsoon Messinian salinity crisis Orbital forcing Pliocene Miocene Salinidade Mudança climática Paleoclimatologia Geoquímica ambiental Evolução Geológica Monção sul africana Crise de salinidade do messiniano Forçante orbital Mioceno Plioceno |
description |
The late Miocene - early Pliocene (7.4 - 4.5 Ma) is a key interval in Earth’s history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of the SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ18O and δ13C recorded in the planktonic foraminifera Orbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling the SAFM. Precession cycles governed precipitation from 7.4 to ~6.9 Ma and during the early Pliocene. From ~6.9 to 5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval appear to influence the isotopic records of Orbulina universa imprinting its long-term variability signal as a response to the ocean and atmospheric reorganization. Precession cycles markedly weakened from 5.9 to 5.3 Ma, almost the same period when the Mediterranean Outflow Water ceased. These findings highlight important teleconnections among the SAFM, Mediterranean Sea, and other tropical regions. |
publishDate |
2024 |
dc.date.none.fl_str_mv |
2024-01-22T19:51:53Z 2024-01-22T19:51:53Z |
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 |
AZEVEDO, Allana Queiroz de. Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene. 2023. 99 f. Tese (Doutorado em Geoquímica - Geoquímica Ambiental) - Universidade Federal Fluminense, Niterói, 2023. http://app.uff.br/riuff/handle/1/32013 |
identifier_str_mv |
AZEVEDO, Allana Queiroz de. Orbital forcing and evolution of the Southern African Monsoon from late Miocene to early Pliocene. 2023. 99 f. Tese (Doutorado em Geoquímica - Geoquímica Ambiental) - Universidade Federal Fluminense, Niterói, 2023. |
url |
http://app.uff.br/riuff/handle/1/32013 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
CC-BY-SA info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
CC-BY-SA |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da Universidade Federal Fluminense (RIUFF) instname:Universidade Federal Fluminense (UFF) instacron:UFF |
instname_str |
Universidade Federal Fluminense (UFF) |
instacron_str |
UFF |
institution |
UFF |
reponame_str |
Repositório Institucional da Universidade Federal Fluminense (RIUFF) |
collection |
Repositório Institucional da Universidade Federal Fluminense (RIUFF) |
repository.name.fl_str_mv |
Repositório Institucional da Universidade Federal Fluminense (RIUFF) - Universidade Federal Fluminense (UFF) |
repository.mail.fl_str_mv |
riuff@id.uff.br |
_version_ |
1811823706466418688 |