The top of Mauna Kea volcano (Hawaii island) is the only highland area of the central Pacific Oce... more The top of Mauna Kea volcano (Hawaii island) is the only highland area of the central Pacific Ocean that has preserved direct morphological evidences of the last glaciation. In order to constrain the age of the last glacial retreat, 9 cobbles and boulders have been sampled at ca. 3600 m on 3 small recessional moraines posterior to the abandonment of
The morpho-tectonic evolution of the Afar triple junction has been debated for long, especially c... more The morpho-tectonic evolution of the Afar triple junction has been debated for long, especially concerning the timing of rift development and basement uplift. Based on a low-T (U-Th)/He study, we have proposed recently that the stability of the Blue Nile river (on the main Ethiopian flood-basalts plateau) could last since the emplacement of the lava pile 25-29 Ma ago, implying
One of the ongoing debates in paleoclimatology is whether climate change in the tropics is simply... more One of the ongoing debates in paleoclimatology is whether climate change in the tropics is simply a response to global climate change, or actually forces it. The Altiplano is a highland area (>3600 m) located in the tropical Andes that is particularly well-suited to address this question since both paleo-glacier footprints and paleolake shorelines are very well preserved in this
Glaciers offer an attractive proxy to document palaeoclimatic conditions at high elevation by pro... more Glaciers offer an attractive proxy to document palaeoclimatic conditions at high elevation by providing additional constraints on regional precipitation patterns, and atmospheric temperature. However little is known about Holocene glacier fluctuations in the Andes and inferred climatic changes. Most recent studies on Holocene glacier fluctuations in the Andes are based on lake sediments and ice core records. These studies showed
This study proposes a quantitative reconstruction of the paleoclimatic conditions (precipitation ... more This study proposes a quantitative reconstruction of the paleoclimatic conditions (precipitation and temperature) in the Central Altiplano during the last deglaciation (18-12 ka). The originality of this approach is to couple modeling of lake levels with reconstruction of paleoglaciers equilibrium lines. Indeed, as lake and glacier have contrasted sensitivities to precipitation and temperature, this join approach potentially allows very precise reconstructions. Our reconstruction is based on a new cosmogenic 3He (3Hec) chronology of the glacial features developed on the Cerro Tunupa (20°S, 68°W) during the last deglacial period (Blard et al., in press). The Tunupa volcano is located in the very center of the endhorreic watershed of the Altiplano, where two remarkable episodes of lake highstand were recorded during the last deglaciation: the Tauca stage, 3770 m, dated at 17-15 ka, and the Coipasa stage, 3700 m, dated at 13-12 ka (Placzek et al., 2006). 3Hec dates suggests that, over ...
The top of Mauna Kea volcano (Hawaii island) is the only highland area of the central Pacific Oce... more The top of Mauna Kea volcano (Hawaii island) is the only highland area of the central Pacific Ocean that has preserved direct morphological evidences of the last glaciation. In order to constrain the age of the last glacial retreat, 9 cobbles and boulders have been sampled at ca. 3600 m on 3 small recessional moraines posterior to the abandonment of
The morpho-tectonic evolution of the Afar triple junction has been debated for long, especially c... more The morpho-tectonic evolution of the Afar triple junction has been debated for long, especially concerning the timing of rift development and basement uplift. Based on a low-T (U-Th)/He study, we have proposed recently that the stability of the Blue Nile river (on the main Ethiopian flood-basalts plateau) could last since the emplacement of the lava pile 25-29 Ma ago, implying
One of the ongoing debates in paleoclimatology is whether climate change in the tropics is simply... more One of the ongoing debates in paleoclimatology is whether climate change in the tropics is simply a response to global climate change, or actually forces it. The Altiplano is a highland area (>3600 m) located in the tropical Andes that is particularly well-suited to address this question since both paleo-glacier footprints and paleolake shorelines are very well preserved in this
Glaciers offer an attractive proxy to document palaeoclimatic conditions at high elevation by pro... more Glaciers offer an attractive proxy to document palaeoclimatic conditions at high elevation by providing additional constraints on regional precipitation patterns, and atmospheric temperature. However little is known about Holocene glacier fluctuations in the Andes and inferred climatic changes. Most recent studies on Holocene glacier fluctuations in the Andes are based on lake sediments and ice core records. These studies showed
This study proposes a quantitative reconstruction of the paleoclimatic conditions (precipitation ... more This study proposes a quantitative reconstruction of the paleoclimatic conditions (precipitation and temperature) in the Central Altiplano during the last deglaciation (18-12 ka). The originality of this approach is to couple modeling of lake levels with reconstruction of paleoglaciers equilibrium lines. Indeed, as lake and glacier have contrasted sensitivities to precipitation and temperature, this join approach potentially allows very precise reconstructions. Our reconstruction is based on a new cosmogenic 3He (3Hec) chronology of the glacial features developed on the Cerro Tunupa (20°S, 68°W) during the last deglacial period (Blard et al., in press). The Tunupa volcano is located in the very center of the endhorreic watershed of the Altiplano, where two remarkable episodes of lake highstand were recorded during the last deglaciation: the Tauca stage, 3770 m, dated at 17-15 ka, and the Coipasa stage, 3700 m, dated at 13-12 ka (Placzek et al., 2006). 3Hec dates suggests that, over ...
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