Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina
The aim of this thesis is to describe present and past coastal dune environments in southern Buenos Aires Province, Argentina. The present vegetation of a dune system and its zonation are described on the basis of air photographs, physiognomy of the dune system and floristic composition. The vegeta...
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Uppsala universitet, Institutionen för geovetenskaper
2004
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ndltd-UPSALLA1-oai-DiVA.org-uu-40002013-01-08T13:03:53ZPresent and Past Coastal Dune Environments of South Buenos Aires Province, ArgentinaengFontana, Sonia L.Uppsala universitet, Institutionen för geovetenskaperUppsala : Acta Universitatis Upsaliensis2004Quaternary geologypollenostracodsdune vegetationHoloceneBuenos Aires ProvinceArgentinaKvartärgeologiQuaternary geologyKvartärgeologiThe aim of this thesis is to describe present and past coastal dune environments in southern Buenos Aires Province, Argentina. The present vegetation of a dune system and its zonation are described on the basis of air photographs, physiognomy of the dune system and floristic composition. The vegetation was characterized by a large number of Poaceae and Asteraceae species. Five vegetation zones, based on floristic composition, were defined by cluster analysis. Pollen-vegetation comparison revealed that pollen assemblages differed considerably from the associated vegetation. Some of the major discrepancies were caused by large differences between pollen and vegetation proportion of Hyalis argentea and Discaria americana. However, the local vegetation was well represented in recent soil samples. Pollen traps recorded predominantly extralocal and regional pollen. A new species of ostracods was recovered from an interdunal lake. The species, a giant cypridid, was described and illustrated, and its geographical distribution and ecology were discussed. Two sediment sequences from the coastal intertidal zone and from a shallow freshwater lake were analysed for loss on ignition, calcareous microfossils (ostracods and foraminifers), macro remains and pollen. The coastal sequence was deposited between 7890 and 7630 cal. BP. Its pollen assemblages were typical for halophytic associations, with some psammophytic taxa also present in recent vegetation. The microfossils were representative of a littoral lagoon. The lake sequence comprised the last 3000 cal. BP. Pollen spectra indicated a relatively stable vegetation composition after the lake had been formed. Pollen assemblages reflected the present regional grassland vegetation with taxa characteristic for the surrounding dune communities. Human settlement was indicated in the pollen spectra by the presence of introduced taxa in the uppermost samples. The data presented provide a useful reference for the interpretation of fossil sequences from similar environments. Doctoral thesis, comprehensive summaryinfo:eu-repo/semantics/doctoralThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4000urn:isbn:91-554-5876-9Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 940application/pdfinfo:eu-repo/semantics/openAccess |
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English |
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Doctoral Thesis |
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Quaternary geology pollen ostracods dune vegetation Holocene Buenos Aires Province Argentina Kvartärgeologi Quaternary geology Kvartärgeologi |
spellingShingle |
Quaternary geology pollen ostracods dune vegetation Holocene Buenos Aires Province Argentina Kvartärgeologi Quaternary geology Kvartärgeologi Fontana, Sonia L. Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
description |
The aim of this thesis is to describe present and past coastal dune environments in southern Buenos Aires Province, Argentina. The present vegetation of a dune system and its zonation are described on the basis of air photographs, physiognomy of the dune system and floristic composition. The vegetation was characterized by a large number of Poaceae and Asteraceae species. Five vegetation zones, based on floristic composition, were defined by cluster analysis. Pollen-vegetation comparison revealed that pollen assemblages differed considerably from the associated vegetation. Some of the major discrepancies were caused by large differences between pollen and vegetation proportion of Hyalis argentea and Discaria americana. However, the local vegetation was well represented in recent soil samples. Pollen traps recorded predominantly extralocal and regional pollen. A new species of ostracods was recovered from an interdunal lake. The species, a giant cypridid, was described and illustrated, and its geographical distribution and ecology were discussed. Two sediment sequences from the coastal intertidal zone and from a shallow freshwater lake were analysed for loss on ignition, calcareous microfossils (ostracods and foraminifers), macro remains and pollen. The coastal sequence was deposited between 7890 and 7630 cal. BP. Its pollen assemblages were typical for halophytic associations, with some psammophytic taxa also present in recent vegetation. The microfossils were representative of a littoral lagoon. The lake sequence comprised the last 3000 cal. BP. Pollen spectra indicated a relatively stable vegetation composition after the lake had been formed. Pollen assemblages reflected the present regional grassland vegetation with taxa characteristic for the surrounding dune communities. Human settlement was indicated in the pollen spectra by the presence of introduced taxa in the uppermost samples. The data presented provide a useful reference for the interpretation of fossil sequences from similar environments. |
author |
Fontana, Sonia L. |
author_facet |
Fontana, Sonia L. |
author_sort |
Fontana, Sonia L. |
title |
Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
title_short |
Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
title_full |
Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
title_fullStr |
Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
title_full_unstemmed |
Present and Past Coastal Dune Environments of South Buenos Aires Province, Argentina |
title_sort |
present and past coastal dune environments of south buenos aires province, argentina |
publisher |
Uppsala universitet, Institutionen för geovetenskaper |
publishDate |
2004 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4000 http://nbn-resolving.de/urn:isbn:91-554-5876-9 |
work_keys_str_mv |
AT fontanasonial presentandpastcoastalduneenvironmentsofsouthbuenosairesprovinceargentina |
_version_ |
1716507567254929408 |