Tropical forest changes during the late quaternary in African and South American lowlands
Arboreal pollen and montane elements of Late Quaternary pollen assemblages from three lacustrine cores (West Cameroon, southeastern Amazonia and central Brazil) are correlated, by the radiocarbon chronology, with other palaeoenvironmental records in Africa and South America. We observe in both conti...
| Autor principal: | Servant, Michel |
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| Outros Autores: | Maley, Jean, Turcq, Bruno Jean, Absy, Maria Lúcia, Brénac, Patrice, Fournier, Marc, Ledru, Marie Pierre |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
Global and Planetary Change
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/19503 |
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oai:repositorio:1-19503 |
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dspace |
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oai:repositorio:1-19503 Tropical forest changes during the late quaternary in African and South American lowlands Servant, Michel Maley, Jean Turcq, Bruno Jean Absy, Maria Lúcia Brénac, Patrice Fournier, Marc Ledru, Marie Pierre Lacustrine Core Pollen Pollen Assemblage Quaternary (late) Radiocarbon Chronology Radiocarbon Dating Tropical Forest Vegetated Succession Vegetation Brazil, Amazonia Cameroon Cameroon, (west) Arboreal pollen and montane elements of Late Quaternary pollen assemblages from three lacustrine cores (West Cameroon, southeastern Amazonia and central Brazil) are correlated, by the radiocarbon chronology, with other palaeoenvironmental records in Africa and South America. We observe in both continents a well-developed dense forest at 30,000 and 9000 yr B.P. The succession of vegetation types during the Late Quaternary appeared strongly related to the regional conditions: (1) the dense forest was more or less degraded depending on the regions during the last full glacial period (20,000-15,000 yr B.P.); (2) a slow increase of tree elements is evidenced in some areas during the Late Glacial (15,000-10,000 yr B.P.), whereas short-term fluctuations occurred in central Brazil during the same time; (3) a strong regression of the forest during the middle Holocene (6000-5000 yr B.P.), in the southern tropical zone of South America, was in opposition to a full forest development in Africa. In both continents two main features characterize the tropical forest evolution: (1) Montane elements developed in the lowlands during the last glacial period and in some southern or northern regions during the early Holocene; and (2) the climate seasonality was enhanced in several regions since 8500-7500 yr B.P. For a tentative explanation, we relate the cold or cool climate, inferred by palaeoecological evidences in the glacial period and glacial-interglacial transition, to polar air-masses reaching more frequently the tropical zone. This interpretation explains the apparent contradiction between the markedly low temperature of the continental lowlands opposed: (1) at 18,000 yr B.P., to the 1-2°C lower Sea Surface Temperature of tropical oceans and (2) to the global warming during the late glacial. During the middle and Late Holocene, climate evolution was mainly influenced by the latitudinal shift of the ITCZ positions in July and January and, in South America, by short-term changes of the zonal atmospheric circulation. © 1993. 2020-06-15T22:09:16Z 2020-06-15T22:09:16Z 1993 Artigo https://repositorio.inpa.gov.br/handle/1/19503 10.1016/0921-8181(93)90038-P en Volume 7, Número 1-3, Pags. 25-40 Restrito Global and Planetary Change |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
Lacustrine Core Pollen Pollen Assemblage Quaternary (late) Radiocarbon Chronology Radiocarbon Dating Tropical Forest Vegetated Succession Vegetation Brazil, Amazonia Cameroon Cameroon, (west) |
| spellingShingle |
Lacustrine Core Pollen Pollen Assemblage Quaternary (late) Radiocarbon Chronology Radiocarbon Dating Tropical Forest Vegetated Succession Vegetation Brazil, Amazonia Cameroon Cameroon, (west) Servant, Michel Tropical forest changes during the late quaternary in African and South American lowlands |
| topic_facet |
Lacustrine Core Pollen Pollen Assemblage Quaternary (late) Radiocarbon Chronology Radiocarbon Dating Tropical Forest Vegetated Succession Vegetation Brazil, Amazonia Cameroon Cameroon, (west) |
| description |
Arboreal pollen and montane elements of Late Quaternary pollen assemblages from three lacustrine cores (West Cameroon, southeastern Amazonia and central Brazil) are correlated, by the radiocarbon chronology, with other palaeoenvironmental records in Africa and South America. We observe in both continents a well-developed dense forest at 30,000 and 9000 yr B.P. The succession of vegetation types during the Late Quaternary appeared strongly related to the regional conditions: (1) the dense forest was more or less degraded depending on the regions during the last full glacial period (20,000-15,000 yr B.P.); (2) a slow increase of tree elements is evidenced in some areas during the Late Glacial (15,000-10,000 yr B.P.), whereas short-term fluctuations occurred in central Brazil during the same time; (3) a strong regression of the forest during the middle Holocene (6000-5000 yr B.P.), in the southern tropical zone of South America, was in opposition to a full forest development in Africa. In both continents two main features characterize the tropical forest evolution: (1) Montane elements developed in the lowlands during the last glacial period and in some southern or northern regions during the early Holocene; and (2) the climate seasonality was enhanced in several regions since 8500-7500 yr B.P. For a tentative explanation, we relate the cold or cool climate, inferred by palaeoecological evidences in the glacial period and glacial-interglacial transition, to polar air-masses reaching more frequently the tropical zone. This interpretation explains the apparent contradiction between the markedly low temperature of the continental lowlands opposed: (1) at 18,000 yr B.P., to the 1-2°C lower Sea Surface Temperature of tropical oceans and (2) to the global warming during the late glacial. During the middle and Late Holocene, climate evolution was mainly influenced by the latitudinal shift of the ITCZ positions in July and January and, in South America, by short-term changes of the zonal atmospheric circulation. © 1993. |
| format |
Artigo |
| author |
Servant, Michel |
| author2 |
Maley, Jean Turcq, Bruno Jean Absy, Maria Lúcia Brénac, Patrice Fournier, Marc Ledru, Marie Pierre |
| author2Str |
Maley, Jean Turcq, Bruno Jean Absy, Maria Lúcia Brénac, Patrice Fournier, Marc Ledru, Marie Pierre |
| title |
Tropical forest changes during the late quaternary in African and South American lowlands |
| title_short |
Tropical forest changes during the late quaternary in African and South American lowlands |
| title_full |
Tropical forest changes during the late quaternary in African and South American lowlands |
| title_fullStr |
Tropical forest changes during the late quaternary in African and South American lowlands |
| title_full_unstemmed |
Tropical forest changes during the late quaternary in African and South American lowlands |
| title_sort |
tropical forest changes during the late quaternary in african and south american lowlands |
| publisher |
Global and Planetary Change |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/19503 |
| _version_ |
1787142118272139264 |
| score |
11.755432 |