Palestra "Antarctica without ice: geological studies on the evolution of the Cenozoic climate of the Western Antarctica"

A Palestra realizou-se no dia 25 de junho de 2018, no LNEG - Polo de Alfragide

Oradora: Anna Mozer
Faculty of Geology, University of Warsaw, Independent Department of Environment and Natural Resources Protection, Żwirki i Wigury 93, 02-089 Warszawa, Poland.

Resumo:

The formation and development of the ice cover on the Antarctic continent occurred as a result of profound changes in the climate of the Earth about 34 million years ago. King George Island (KGI), which was part of the Antarctic Peninsula at that time and located in the volcanic arc of South Shetland Islands, is one of the few known places with a record of the period preceding the development of the Antarctic ice sheet. From the thermal maximum [PETM] around borderline of the Paleocene and Eocene with a slight deviation in the early/middle Eocene [E/MECO], there was an uninterruptedly cooling climate trend that led to a general cooling in Eocene and the earliest Oligocene, in the period immediately preceding the development of glacial conditions. This coolness is recorded in a rock successes that were formed in the conditions of the volcanic front on the South Shetland arc, dominated by stratovolcanoes and basaltic-andesitic lava fields. They were accompanied by depressions and erosional cuts, in which sedimentary sequences of various factions accumulated, from siltstones to conglomerates, rich in plant detritus, occurring alternately with basaltic and andesitic lava flows. From these exposures come the famous fossil flora of West Antarctica, which served to reconstruct vegetation types for the entire region. This flora is a direct proof of Antarctica's preglacial history, which goes down the stratigraphic table from the Cretaceous period to the early Oligocene (32 ± 0.5 Ma from strontium research). The rapid progradation of the West Antarctic ice cover in the early Oligocene was preceded by the presence of three preglacial palaeoclimate and palaeoenvironmental stages of the Paleocene-Eocene. They contain the record of climate change in terrestrial environments, from humid and warm climate to moderate (PGS-1 stage), through a dry climate with a pronounced cooling trend (PGS-2 stage) up to cold and humid climatic conditions (PGS-3 stage).

Nota biográfica:

Anna Mozer é geóloga e professora na Faculdade de Geologia da Universidade de Varsóvia, Polónia. Licenciou-se em 2008 na mesma faculdade e obteve o grau de doutoramento no Institute of Geological Sciences, Polish Academy of Sciences em 2013, com a apresentação da respectiva tese intitulada "Paleogene preglacial sedimentary environments of King George Island, West Antarctica". Tem realizado trabalhos de investigação no âmbito da reconstrução de paleoambientes, geocronologia, geoquímica e paleobotânica com a finalidade de realizar interpretações paleoclimáticas.

Com a apresentação da palestra intitulada "Antarctica without ice: geological studies on the evolution of the Cenozoic climate of the Western Antarctica", Anna Mozer, para além de ter apresentado e discutido os dados científicos do seu trabalho, abordou as questões técnicas envolvidas no trabalho de campo na ilha King George (onde acampou com frequência), bem como as condições de trabalho e vivência na Base Polar Antárctica Henryk Arctowski. Tudo isto foi acompanhado de muitas fotografias, únicas e somente possíveis de obter nesta região polar do nosso planeta.

Destinatários:

Investigadores, Técnicos e Público em geral.

Data e hora:

25 de junho de 2018, às 15:00h.

Localização

Pesquisar nesta área