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| Zukin, J-h; Francheteau, J. |
| Detailed studies of the Easter microplate, and other contemporary microplates located along the world's mid-oceanic ridge system, are considered of primary importance to our understanding of the kinematic evolution of the major oceanic plates. The focus of the Rapanui expedition, part of the "Tour du monde" of the French research vessel Jean Charcot , was to collect detailed structural and geophysical data along the northern and southern Easter microplate boundaries in order to test, in a rigorous manner, the most recent tectonic and kinematic models for the microplate. In developing detailed bathymetric, morphotectonic and magnetic maps of these boundaries, we have found that our new plate boundaries differ considerably from those of Hey et al. (1985). |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37895/35976.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... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37954/36035.pdf |
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| Geli, Louis; Lee, T; Cochran, J; Francheteau, J; Abbott, D; Labails, Cinthia; Appriou, D. |
| We analyze available heat flow data from the flanks of the Southeast Indian Ridge adjacent to or within the Australian-Antarctic Discordance (AAD), an area with patchy sediment cover and highly fractured seafloor as dissected by ridge- and fracture-parallel faults. The data set includes 23 new data points collected along a 14-Ma old isochron and 19 existing measurements from the 20- to 24-Ma old crust. Most sites of measurements exhibit low heat flux (from 2 to 50 mW m(-2)) with near-linear temperature-depth profiles except at a few sites, where recent bottom water temperature change may have caused nonlinearity toward the sediment surface. Because the igneous basement is expected to outcrop a short distance away from any measurement site, we hypothesize... |
| Tipo: Text |
Palavras-chave: Mid ocean ridges; Heat flow; Marine geophysics. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3878.pdf |
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| Juteau, T; Eissen, Jp; Francheteau, J; Needham, David; Choukroune, P; Rangin, C; Seguret, M; Ballard, Rd; Fox, Pj; Normark, Wr; Carranza, A; Cordoba, D; Guerrero, J. |
| Fort y basaltic rocks collected by submersible during the "Cyamex" expedition (1978) on the East PacifIc Rise at 21 oN, a moderately fast spreading segment (6 cm/year opening rate) of the mid-ocean ridge, consist of angular pillow fragments and glass buds, sheet-flow slabs and samples of columnar pillars standing in collapsed fossillava pools. Most of the rocks are from the crestal are a of the Rise. The collection shows a striking petrographic homogeneity wh en compared with the range of basalts found on other segments of midocean ridges: olivine-phyric, or highly plagioclase-phyric rocks, so common in the slowspreading "Famous" are a in the Atlantic, are absent. All samples are typical lowpotassium oceanic tholeiites with a limited fractionation trend.... |
| Tipo: Text |
Palavras-chave: Dorsale Est-PacifIque Pétrologie des basaltes sous-marins Coussins; Laves fluides; Piliers Générations de cristaux Globules de sulfure East Paciflc Rise Petrology of submarine basalts Pillows; Sheet flows; Pillars Generations of crystals Sulphide globules. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/00323/43430/43112.pdf |
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| Rangin, C; Francheteau, J. |
| Manned submersible observations on a transect from the axis of the East Pacific Rise (21 degree N) to the area of the Brunhes-Matuyama magnetic inversion were made during the Cyamex and Rise diving phases of the Rita project. In the northern part of the study area, axial, linear, 400 to 600 m-wide topographic highs are formed by relatively unfaulted fresh pillow-lava-flows (zone 1). Flanking the axis of recent volcanism is a 1,200 to 1,500 m-wide zone of highly fractured volcanic hilly terrain (zone 2). Zone 3, could represent a former, large flooding episode of the sea floor at the axis of the Rise. Tectonic activity is particularly evident in zone 2, decreases rapidly across strike, and vanishes 12 km from the axis of the East Pacific Rise. The... |
| Tipo: Text |
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| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/00246/35691/34199.pdf |
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| Hoffert, M; Perseil, A; Hekinian, Roger; Choukroune, P; Needham, Hd; Francheteau, J; Le Pichon, X. |
| Deep-sea hydrothermal deposits were observed, mapped and sampled in situ with the submersible "Cyana" in the Famous area of the Mid-Atlantic Ridge.Two neighbouring fields, each covering an area of about 600 m2, are associated with low, E-W trending sediment-covered ridges that lie at a depth of about 2 700 m close to the axis of Transform Fault "A".In each field the deposits are thicker (up to about 1 m) close to the small, fissure-like vents through which they were evidently delivered. Despite their heterogeneous composition, their mineralogical and chemical variations have an orderly pattern.The principal constituents are a green clay-rich material, and Fe-Mn oxides in the form of black concretions. The relative abundances of these products vary with... |
| Tipo: Text |
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| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5216.pdf |
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| Francheteau, J; Patriat, P; Segoufin, J; Armijo, R; Doucoure, M; Yelles-chaouche, K; Zukin, J; Calmant, S; Naar, D; Searle, R. |
| The Rapanui Expedition consisted of three legs. The first leg (named Manrap) was a transit between Manzanillo, Mexico and Easter Island, Chile, the second leg (Rapanui 1) consisted of work on the Rapanui (Easter) microplate and was the primary workload of the expedition, and the third leg (Rapanui 2) was a transit from Easter Island, Chile to Tahiti, French Polynesia, and realized additional work on the Rapanui Microplate, and a fuel stop at Hao, French Polynesia. Instrumentation on all legs consisted of standard geophysical tools used on the N/O Jean Charcot . |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37949/36030.pdf |
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