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| Bassinot, Franck; Beaufort, Luc; Vincent, Edith; Labeyrie, Laurent; Rostek, Frauke; Muller, Pj; Quidelleur, Xavier; Lancelot, Y. |
| We examined coarse fraction contents of pelagic carbonates deposited between 2000- and 3700-m water depth in the tropical Indian Ocean using ocean Drilling Program (ODP) sites 722 (Owen Ridge, Arabian Sea) and 758 (Ninetyeast Ridge, eastern equatorial Indian Ocean), and four giant piston cores collected by the French RN Marion Dufresne during the SEYMAMA expedition. Over the last 1500 kyr, coarse fraction records display high-amplitude oscillations with an irregular wavelength on the order of approximately 500 kyr. These oscillations can be correlated throughout the entire equatorial Indian Ocean, from the Seychelles area eastward to the Ninetyeast Ridge, and into the Arabian Sea. Changes in grain size mainly result from changes in carbonate dissolution as... |
| Tipo: Text |
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| Ano: 1994 |
URL: https://archimer.ifremer.fr/doc/00100/21114/37251.pdf |
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| Cheminee, J F; Albarede, F; Devey, C W; Francheteau, J; Hekinian, R; Lancelot, Y; Talandier, J. |
| The Teahitia-Mehetia hot spot region located in the southeastern extension of the Society Islands chain, near 18 degree S-148 degree W consists of several active volcanoes. The distribution of recent volcanic activity correlates with seismic epicenters, and covers an area of more than 1000 km super(2). Intermittent volcanic activity has given rise to large (> 1000 m high) and small (< 500 m high) edifices composed of various types of flows. Several recent volcanic events have produced a suite of alkalic rocks ranging from ankaramites, through alkali basalts to trachyphonolites. The presence of altered MORB-like tholeiites on one small seamount suggests that a different mantle source material was involved in forming some of the crust in this hot spot... |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37954/36035.pdf |
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| Lancelot, Y; Froger, V; Cheminee, J L; Galisson, H; Larson, R; Mauffret, A; Schlanger, So; Sclater, J G. |
| The Mesopac Cruise was the first multichannel seismic study of the western basins of the Pacific Plate. It was concentrated in the Nauru Basin and in the western area of the Central Pacific Basin. Profiles were calibrated with drilling results from DSDP Sites 462 and 169. For the first time one could observe reflectors within the Cretaceous volcanic complex down to approximately equals 8.5 seconds. Profiles did not allow direct observation of the top of the oceanic crust. After correcting for the load on top of the oceanic crust, results suggest that it cannot lie much deeper than those reflectors. If the oceanic crust lies only a few hundred meters beneath the 2.4 km thick complex, it would be right on the normal thermal subsidence curve corresponding to... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37906/35987.pdf |
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| Auzende, J M; Rad, Uvon; Biju-duval, B; Cepek, P; Dostmann, H; Jaffrezo, M; Lancelot, Y; Ruellan, E. |
| The stratigraphy and structure of the old, starved passive margin of the Mazagan Plateau and the adjacent Escarpment which extends from 1,000-3,000 m water depth was studied during the cofinanced French-German CYAMAZ deep diving campaign which obtained 130 in-situ samples, supplemented by direct sea floor observations during 18 dive traverses. The facies evolution of the Mazagan carbonate platform between kimmeridgian and Valanginian times was mainly influenced by blockfaulting and sea-level fluctuations. Regressive periods occurred during Kimmeridgia/Tithonian and Late Berriasian times, and are separated by a late Tithonian/early Berriasian transgression. The drowning of the main carbonate platform and the Early Cretaceous to Paleogene history of the... |
| Tipo: Text |
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| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/00247/35830/34340.pdf |
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| Cheminee, J-l; Hekinian, Roger; Talandier, J; Albarede, F; Devey, C W; Francheteau, Jean; Lancelot, Y. |
| The Teahitia-Mehetia hot spot region located in the southeastern extension of the Society Islands chain, near 18 degree S-148 degree W, consists of several active volcanoes. The distribution of recent volcanic activity correlates with seismic epicenters, and covers an area of more than 1,000 km super(2). Intermittent volcanic activity has given rise to large (> 1,000 m high) and small (< 500 m high) edifices composed of various types of flows. Several recent volcanic events have produced a suite of alkalic rocks ranging from ankaramites, through alkali basalts to trachy-phonolites. The presence of altered MORB-like tholeiites on one small seamount suggests that a different mantle source material was involved in forming some of the crust in this hot... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37896/35977.pdf |
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| Cayre, O; Lancelot, Y; Vincent, E; Hall, Ma. |
| A quantitative analysis of planktonic foraminifera in a core from the Iberian Margin allows a reconstruction of the evolution of oceanographic parameters during the last glacial cycle with a resolution of similar to 1000 years. A principal component analysis performed on 19 species allows the identification of 11 intervals characterized by increased abundances of the subpolar species. The youngest six of these intervals are correlated with the last 6 Heinrich events (HEs). The five cold events older than stage 4 are dated at 81, 90, 110, 129, and 140 ka, respectively. Paleotemperatures reconstructed using the modern analog technique indicate 4 degrees C decreases during all even-numbered isotopic stages and stage 3. During the HEs, temperature decreases... |
| Tipo: Text |
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| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35062/34594.pdf |
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| Froger, V; Lancelot, Y. |
| The western part of the Pacific plate, where the oceanic crust is of Jurassic age, has undergone exceptional volcanic activity during the Cretaceous. It has produced numerous volcanoes (oceanic islands, guyots, seamounts) as well as very thick accumulation of volcanogenic material in the deep basins. The Mesopac cruise of the R/V Jean Charcot in the Nauru Basin obtained multichannel seismic profiles for the first time in these regions. This technique aimed at estimating the thickness of the cretaceous volcanics and locating the top of the underlying Jurassic crust. The results, when compared with those of DSDP drill holes, demonstrate that the abnormally shallow depth of the Nauru Basin results from an accumulation of flows and sills that constitute a... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37922/36003.pdf |
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