Consulta: creatorFacets:"Lamy, F."
Registros recuperados: 6
Data/hora: 26/07/2024 22:52:42

Changes in the advection of Antarctic Intermediate Water to the northern Chilean coast during the last 970 kyr
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Martinez-mendez, G.; Hebbeln, D.; Mohtadi, M.; Lamy, F.; De Pol-holz, R.; Reyes-macaya, D.; Freudenthal, Tim.
The Antarctic Intermediate Water (AAIW) is a key player in global-scale oceanic overturning processes and an important conduit for heat, fresh water, and carbon transport. The AAIW past variability is poorly understood mainly due to the lack of sedimentary archives at intermediate water depths. We present records of benthic stable isotopes from sediments retrieved with the seafloor drill rig MARUM-MeBo at 956m water depth off northern Chile (GeoB15016, 27 degrees 29.48S, 71 degrees 07.58W) that extend back to 970ka. The sediments at this site are presently deposited at the boundary between AAIW and Pacific Deep Water (PDW). For previous peak interglacials, our results reveal similar benthic C-13 values at site GeoB15016 and of a newly generated stack of...
Tipo: Text
Palavras-chave: Paleoceanography; AAIW; Advection changes.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00263/37459/35821.pdf

Estimated reservoir ages of the Black Sea since the last glacial
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Kwiecien, O.; Arz, H. W.; Lamy, F.; Wulf, S.; Bahr, A.; Roehl, U.; Haug, G. H.
Accelerator mass spectrometry (AMS) radiocarbon dating of ostracod and gastropod shells from the southwestern Black Sea cores combined with tephrochronology provides the basis for studying reservoir age changes in the late-glacial Black Sea. The comparison of our data with records from the northwestern Black Sea shows that an apparent reservoir age of similar to 1450 C-14 yr found in the glacial is characteristic of a homogenized water column. This apparent reservoir age is most likely due to the hardwater effect. Though data indicate that a reservoir age of similar to 1450 C-14 yr may have persisted until the Bolling-Allerod warm period, a comparison with the GISP2 ice-core record suggests a gradual reduction of the reservoir age to similar to 1000 C-14...
Tipo: Text
Palavras-chave: Mediterranean abyssal sediments; Minoan eruption; Tephra layers; Radiocarbon; Santorini; Deglaciation; History; Variability; Calibration; Resolution.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00209/31990/30430.pdf

Millennial-scale sea surface temperature and Patagonian Ice Sheet changes off southernmost Chile (53 degrees S) over the past similar to 60 kyr
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Caniupan, M.; Lamy, F.; Lange, C. B.; Kaiser, J.; Arz, H.; Kilian, R.; Baeza Urrea, O.; Aracena, C.; Hebbeln, D.; Kissel, C.; Laj, C.; Mollenhauer, G.; Tiedemann, R.
Glacial millennial-scale paleoceanographic changes in the Southeast Pacific and the adjacent Southern Ocean are poorly known due to the scarcity of well-dated and high resolution sediment records. Here we present new surface water records from sediment core MD07-3128 recovered at 53 degrees S off the Pacific entrance of the Strait of Magellan. The alkenone-derived sea surface temperature (SST) record reveals a very strong warming of ca. 8 C over the last Termination and substantial millennial-scale variability in the glacial section largely consistent with our planktonic foraminifera oxygen isotope (delta(18)O) record of Neogloboquadrina pachyderma (sin.). The timing and structure of the Termination and some of the millennial-scale SST fluctuations are...
Tipo: Text
Palavras-chave: Patagonian Ice Sheet; Alkenones; Ice rafted debris; Millennial-scale changes; Southeast Pacific.
Ano: 2011
URL: https://archimer.ifremer.fr/doc/00214/32516/31000.pdf

Precipitation as the main driver of Neoglacial fluctuations of Gualas glacier, Northern Patagonian Icefield
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bertrand, S.; Hughen, K. A.; Lamy, F.; Stuut, J. -b. W.; Torrejon, F.; Lange, C. B.
Glaciers are frequently used as indicators of climate change. However, the link between past glacier fluctuations and climate variability is still highly debated. Here, we investigate the mid- to late-Holocene fluctuations of Gualas Glacier, one of the northernmost outlet glaciers of the Northern Patagonian Icefield, using a multi-proxy sedimentological and geochemical analysis of a 15 m long fjord sediment core from Golfo Elefantes, Chile, and historical documents from early Spanish explorers. Our results show that the core can be sub-divided into three main lithological units that were deposited under very different hydrodynamic conditions. Between 5400 and 4180 cal yr BP and after 750 cal yr BP, sedimentation in Golfo Elefantes was characterized by the...
Tipo: Text
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00274/38496/36958.pdf

Radiocarbon constraints on the extent and evolution of the South Pacific glacial carbon pool
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ronge, T. A.; Tiedemann, R.; Lamy, F.; Koehler, P.; Alloway, B. V.; De Pol-holz, R.; Pahnke, K.; Southon, J.; Wacker, L.
During the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (Delta C-14) suggest the release of C-14-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this C-14-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores retrieved along a South Pacific transect to reconstruct the spatio-temporal evolution of Delta C-14 over the last 30,000 years. In similar to 2,500-3,600 m water depth, we find C-14-depleted deep waters with a maximum glacial offset to atmospheric (14)(C) (Delta Delta C-14 = -1,000%). Using a box model, we test the hypothesis that these low values might have been caused by an interaction of aging and...
Tipo: Text
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00421/53251/54716.pdf

Turbiditic trench deposits at the South-Chilean active margin: A Pleistocene-Holocene record of climate and tectonics
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Blumberg, S.; Lamy, F.; Arz, H. W.; Echtler, H. P.; Wiedicke, M.; Haug, G. H.; Oncken, O.
The active plate margin of South America is characterized by a frequent occurrence of large and devastating subduction earthquakes. Here we focus on marine sedimentary records off Southern Chile that are archiving the regional paleoseismic history over the Holocene and Late Pleistocene. The investigated records - Ocean Drilling Program (ODP) Site 1232 and SONNE core 50SL - are located at similar to 40 degrees S and similar to 38 degrees S, within the Peru-Chilc trench, and are characterized by frequent interbedded strata of turbiditic and hemipelagic origin. On the basis of the sedimentological characteristics and the association with the active margin of Southern Chile, we assume that the turbidites are mainly scismically triggered, and may be considered...
Tipo: Text
Palavras-chave: Turbidite frequency; Earthquake recurrence; Chile active margin; Trench deposits; Paleoseismology; Paleoclimate.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00237/34850/33217.pdf