Encontrados 5 documentos, a visualizar página 1 de 1
A first last glacial maximum to younger dryas stalagmite record from southern P...
Veiga-Pires, C.; Ghaleb, Bassam; Hélie, Jean-François; Moura, Delminda; Luis, Joaquim; Hillaire-Marcel, C.A newly launched research program permitted the sampling of speleothem deposit in the Algarve area (Southern Portugal) with the primary objective of constraining the ages of past humid intervals in the area from U-series measurements. ; Os sedimentos estuarinos constituem valiosos registos das variações das condições climáticas e ambientais regionais
A first last glacial maximum stalagmite record from southern Portugal
Veiga-Pires, C.; Ghaleb, Bassam; Hélie, Jean-François; Moura, Delminda; Luis, Joaquim; Hillaire-Marcel, C.A newly launched research program permitted the sampling of speleothem deposits in the Algarve area (Southern Portugal). Unfortunately, this stalagmite yielded very small amounts of U (~ 20 ppb), making the setting of a U-series chronology difficult due to both the relative importance of a detrital contaminating fraction and the lack of precision on overall 230Th measurements. Nevertheless, based on the top and...
First isotopic records from stalagmites in Algarve (South Portugal)
Veiga-Pires, C.; Moura, Delminda; Luis, Joaquim; Varela, J.; Ghaleb, Bassam; Hélie, Jean-François; Hillaire-Marcel, C.Os espeleotemas representam registos paleoclimáticos continentais de alta resolução e estão a ser cada vez mais estudos para fins de reconstrução climática de períodos não afectados por acções antropogénicas. Na região do Algarve (Sul de Portugal), a existência de formações carbonatadas do Jurássico e Cretácico permitiu um desenvolvimento de sistemas cársicos onde se encontram actualmente estruturas estalagmíti...
A glaciological perspective on Heinrich events
Clarke, G. K. C.; Marshall, S. J.; Veiga-Pires, C.; Bilodeau, G.; Hillaire-Marcel, C.Heinrich events, the massive episodic disgorgement of sediment-laden ice from the Laurentide Ice Sheet to the North Atlantic Ocean, are a puzzling instability of the Ice-Age climate system. Although there is broad agreement on the defining characteristics of Heinrich events, the glaciological mechanisms remain controversial. Paleoceanographic records show that Heinrich events tend to occur at the culmination of...
U and Th isotope constraints on the duration of Heinrich events H0-H4 in the so...
Veiga-Pires, C.; Hillaire-Marcel, C.The duration and sequence of events recorded in Heinrich layers at sites near the Hudson Strait source area for ice-rafted material are still poorly constrained, notably because of the limit and uncertainties of the 14C chronology. Here we use high-resolution 230Th-excess measurements, in a 6 m sequence raised from Orphan Knoll (southern Labrador Sea), to constrain the duration of the deposition of the five mos...
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