Poura comporte trois types de formations: des roches volcaniques intrusives, effusives et pyroclastiques, des roches volcano-sédimentaires et des intrusions de granitoïdes. Les roches volcaniques comportent des ultrabasites, des basaltes qui peuvent se présenter en pillow-lavas ,
Il est marqué par des plateaux cuirassés à différentes altitudes. Chaque série de plateaux correspondrait à un événement climatique donné, La zone de Larafella (Figure 21) est caractérisée par un système latéritique ,
Elle est raccordée à l'unité moyenne et s'étale avec une pente très faible d'environ 1 %, jusqu'au Mouhoum ,
altitude avec l'unité haute est d'environ une vingtaine de mètres. Elle est également fortement cuirassée (jusqu'à 10 mètres) ,
Deboffle for their continuing expertise in AMS measurements ,
This work was supported by INSU-CNRS through the DBT Program Thème 1: "Fleuves et érosion". Tandétron operation is supported by the CNRS ,
Les phytolithes, indicateurs du cycle biogéochimique du silicium en forêt équatoriale, C.R. Acad. Sci. Paris, vol.319, issue.4, pp.453-458, 1994. ,
Distribution de l'or dans l'environnement des sites aurifères filoniens et disséminés de Balago-Larafella (Burkina-Faso), 1993. ,
Burkina Faso) Evolution dans les altérites et les cuirasses ferrugineuses (métallogénie, pétrologie, géomorphologie)., Université d'Aix-Marseille III, Faculté des sciences et techniques de Saint Jérôme, p.261, 1996. ,
A study of the absolute intensity of muons at sea level and under various thicknesses of absorber, Journal of Physics G: Nuclear Physics, vol.9, issue.12, pp.1577-1595, 1983. ,
DOI : 10.1088/0305-4616/9/12/018
The last deglaciation: absolute and radiocarbon chronologies. Series I: global Environmental Change, 1992. ,
The contribution of termites to the formation of laterites, Ils. Intern. Seminar on laterisation Processes, pp.262-270, 1983. ,
Formation and transformation processes of iron duricrust systems in tropical humid environment, Chemical Geology, vol.106, issue.1-2, pp.77-101, 1993. ,
DOI : 10.1016/0009-2541(93)90167-H
Using in situ produced cosmogenic isotopes to estimate rates of landscape evolution: A review from the geomorphic perspective, Journal of Geophysical Research: Solid Earth, vol.21, issue.44, pp.13885-13896, 1994. ,
DOI : 10.1029/94JB00459
Les latérites., Livre jubilaire du cinquantenaire de l'Association Française pour l'Etude du, pp.123-138, 1984. ,
Structural characteristics of hematite and goethite and their relationships with kaolinite in a laterite from Cameroon. A TEM study, Bulletin de Minéralogie, vol.111, pp.149-166, 1988. ,
Etude de la géochimie de l'isotope cosmogénique 10 Be et de son isotope stable 9 Be en milieu océanique. Application à la datation des sédiments marins, 1988. ,
African laterite dynamics using in situ-produced 10 Be, Geochimica and Cosmochimica Acta, 1998. ,
URL : https://hal.archives-ouvertes.fr/in2p3-00000210
Contribuição a geomorfológia do Brasil Central, Rev. Bras. Geogr, p.32, 1971. ,
Abstract, Quaternary Research, vol.24, issue.01, pp.11-23, 1993. ,
DOI : 10.1029/JB094iB12p17907
Be in near-surface rocks from the Congo, Geophysical Research Letters, vol.92, issue.6, pp.703-706, 1995. ,
DOI : 10.1029/95GL00167
URL : https://hal.archives-ouvertes.fr/in2p3-00000589
The development of iron crust lateritic systems in Burkina Faso, West Africa examined with in-situ-produced cosmogenic nuclides, Earth and Planetary Science Letters, vol.124, issue.1-4, pp.19-33, 1994. ,
DOI : 10.1016/0012-821X(94)00087-5
URL : https://hal.archives-ouvertes.fr/in2p3-00000701
Al in quartz: Implications for exposure age dating, Geophysical Research Letters, vol.105, issue.4, pp.369-372, 1992. ,
DOI : 10.1029/92GL00266
URL : https://hal.archives-ouvertes.fr/in2p3-00000900
Examination of surface exposure ages of Antarctic moraines using in situ produced 10Be and 26Al, Geochimica et Cosmochimica Acta, vol.55, issue.8, pp.2269-2283, 1991. ,
DOI : 10.1016/0016-7037(91)90103-C
Denudation rates determined from the accumulation of in situ-produced 10 Be in Luquillo experimental Forest, pp.193-202, 1995. ,
URL : https://hal.archives-ouvertes.fr/in2p3-00000586
1807. A journey from Malabar through the countries of Mysor, Canara et Malabar, vol.2, pp.436-460 ,
Geomorphology and In-Situ Cosmogenic Isotopes, Annual Review of Earth and Planetary Sciences, vol.22, issue.1, pp.273-317, 1994. ,
DOI : 10.1146/annurev.ea.22.050194.001421
Nuclear transmutation by negative stopped muons and the activity induced by the cosmic-ray muons, Nuclear Physics A, vol.166, issue.2, pp.145-161, 1971. ,
DOI : 10.1016/0375-9474(71)90419-2
Recherche d'une terminologie typologique applicable aux sols ferralitiques, Cahier ORSTOM, Sér. Pédol, issue.1, pp.25-43, 1972. ,
Improving in Situ Cosmogenic Chronometers, Quaternary Research, vol.44, issue.3, pp.366-376, 1996. ,
DOI : 10.1006/qres.1995.1081
L'or, traceur de l'histoire chimique et physique de l'altérosphère latéritique sous foret équatorial, 1992. ,
Equatorial rain forest lateritic mantles: A geomembrane filter, Geology, vol.20, issue.6, pp.523-526 ,
DOI : 10.1130/0091-7613(1992)020<0523:ERFLMA>2.3.CO;2
Zircon: an immobile index in soils?, Chemical Geology, vol.107, issue.3-4, pp.273-276, 1993. ,
DOI : 10.1016/0009-2541(93)90189-P
Gold: a tracer of the dynamics of tropical laterites, Geology, vol.25, issue.1, pp.81-84, 1997. ,
DOI : 10.1130/0091-7613(1997)025<0081:GATOTD>2.3.CO;2
URL : https://hal.archives-ouvertes.fr/hal-01458899
Contribution à l'étude des "stone-lines" dans la région du moyen-Ogooué (Gabon)., Cahier, pp.3-42, 1969. ,
CHLORINE-36 IN NATURE, Annals of the New York Academy of Sciences, vol.64, issue.5, pp.105-122, 1955. ,
DOI : 10.1111/j.1749-6632.1955.tb35368.x
Nappes de gravats et couvertures argilo-sableuses au Bas-Congo; leur genèse et l'action des termites, Etudes sur les termites africains, pp.399-414, 1964. ,
Cosmogenic radionuclide production in terrestrial rocks: accelerator mass spectrometry measurements and Monte carlo simulations, p.155, 1995. ,
Sur l'importance des phénomènes biologiques dans la formation des cuirasses ferrugineuses en zone intertropicale, CR Acad.Sci, issue.15, pp.233-804, 1951. ,
Overview of the Workshop on Secular Variations in Production Rates of Cosmogenic Nuclides on Earth, Radiocarbon, vol.92, issue.2, pp.135-173, 1996. ,
DOI : 10.1038/331675a0
Overview of the Workshop on Secular Variations in Production Rates of Cosmogenic Nuclides on Earth, Radiocarbon, vol.92, issue.2, pp.135-173, 1996. ,
DOI : 10.1038/331675a0
Applanissements cuirassés et enrichissement des gisements de manganèse dans quelques régions d'Afrique de l'Ouest, Mem. ORSTOM, vol.82, p.275, 1976. ,
Observation sur la génèse des nappes de gravats dans les sols tropicaux, INEAC Ser.Sci. Bruxelles, vol.64, p.37, 1952. ,
Laterites and lateritization processes, 1988. ,
L'accumulation des sesquixydes libres dans les sols tropicaux, Sér. Sci, vol.62, issue.132, 1954. ,
A geomorfológia do Brasil oriental, Rev. Bras. Geogr, vol.18, issue.2, pp.147-265, 1956. ,
Revealing histories of exposure using in situ produced 26 Al and 10 Be in Libyan desert glass, Radiocarbon, issue.2A, pp.28-547, 1986. ,
Chemical isolation of quartz for measurement of in-situ -produced cosmogenic nuclides, Geochimica et Cosmochimica Acta, vol.56, issue.9, pp.3583-3587, 1992. ,
DOI : 10.1016/0016-7037(92)90401-4
Cosmogenic nuclides produced in situ in terrestrial solids. Nuclear Instruments Method in Physics research, pp.238-245, 1987. ,
In Situ-Produced Cosmogenic Isotopes in Terrestrial Rocks, Annual Review of Earth and Planetary Sciences, vol.16, issue.1, pp.355-388, 1988. ,
DOI : 10.1146/annurev.ea.16.050188.002035
Cosmic ray labeling of erosion surfaces: in situ nuclide production rates and erosion models, Earth and Planetary Science Letters, vol.104, issue.2-4, pp.424-439, 1991. ,
DOI : 10.1016/0012-821X(91)90220-C
Tracing quartz through the environment, Proc. Indian Acad. Sci. (Earth Planet. Sci.), pp.1-5, 1985. ,
DOI : 10.1007/BF02863403
In situ cosmogenic 3 H 14 C and 10 Be for determining the net accumulation and ablation rates of ices sheets, Journal of Geophysical Research, issue.B6, pp.92-4947, 1987. ,
Cosmogenic 10 Be in Zaire alluvial diamonds: implications for 3 He contents of diamonds, Nature, pp.139-141, 1987. ,
Cosmic Ray Produced Radioactivity on the Earth, Handb. Phys, pp.551-612, 1967. ,
DOI : 10.1007/978-3-642-46079-1_7
Reconnaissance pédologique le long de la voie ferrée Comilog, République du Congo. Pédol, p.149, 1962. ,
Stone line profiles: Importance in geochemical exploration, Journal of Geochemical Exploration, vol.30, issue.1-3, pp.35-61, 1988. ,
DOI : 10.1016/0375-6742(88)90049-0
Les concentrations de fer dans les sols développés sur le socle granitogneissique du Togo, Cahier ORSTOM, Ser. Pédol, vol.16, issue.1, pp.3-22, 1978. ,
Radiocarbon dating, 1952. ,
Laterites., Laterite and landscape, p.151, 1976. ,
Géochimie de la surface et forme du relief, Sci. Geol. Bull, vol.30, pp.229-233, 1977. ,
Weathering sequencesClimatic" planations. Leveled surfaces and paleosurfaces, VII th Intern. Clay Conf. Develop. in sedim., Bologne et Paire, pp.585-593, 1981. ,
Géochimie et paysages tropicaux, La recherche, vol.7, issue.65, pp.236-244, 1976. ,
Transformations isovolumétriques dans les phénomènes de latérisation et de bauxitisation, Bull. Serv. Carte Géol; Alsace-Lorraine, vol.8, pp.3-10, 1955. ,
Weathering and the formation of hillslope deposits in the tropical highlands of Itatiaia (southeastern Brazil) Catena, pp.81-103, 1996. ,
The concentration of stones into a stone-line, as a result from subsurface movements in fine and loose soils in the tropics, GEO-Eco-Trop, vol.11, issue.14, p.22, 1987. ,
Analyse des différentiations minéralogiques et structurales d'un sol ferralitique à horizons nodulaires du Congo, Cahier O.R.S.T.O.M., série pédologie, vol.18, pp.87-109, 1981. ,
Analyse pétrologique d'une formation latéritique meuble du Cameroun. Essai de traçage d'une différenciation supergène par les paragenèses minérales secondaires, 1988. ,
Crystal chemistry of kaolinite and Fe-Mn oxides; relation with formation conditions of low temperature systems, American Journal of Science, vol.295, issue.9, pp.1115-1155, 1995. ,
DOI : 10.2475/ajs.295.9.1115
Dissolution of kaolinites and accumulation of iron oxides in lateritic-ferruginous nodules: Mineralogical and microstructural transformations, Geoderma, vol.37, issue.2, pp.113-136, 1986. ,
DOI : 10.1016/0016-7061(86)90025-X
Tracing kaolinites through their defect centers; kaolinite paragenesis in a laterite (Cameroon), Economic Geology, vol.84, issue.3, pp.694-707, 1989. ,
DOI : 10.2113/gsecongeo.84.3.694
Cuirasses ferrugineuses et encroûtement calcaires au Sénégal Occidental et en Mauritanie. Systèmes évolutifs. Géochimie, structures, relais et coexistence, Sci. Geol, p.232, 1976. ,
Evolution of Iron Crusts in Tropical Landscapes, 1986. ,
Rates of chemical weathering of rocks and minerals, pp.169-191 ,
Microgeochemical environments in lateritic weathering Geochemistry and Mineral Formation in the Earth Surface, pp.141-156, 1987. ,
Self-organization in chemical lateritic weathering, Geoderma, vol.51, issue.1-4, pp.5-13, 1991. ,
DOI : 10.1016/0016-7061(91)90063-Y
Mineralogy, petrography and structures of iron crusts (ferricretes) developed on sandstones in the western part of Senegal, Geoderma, vol.19, issue.4, pp.263-277, 1977. ,
DOI : 10.1016/0016-7061(77)90069-6
Cosmic ray produced 10Be and 26Al in Antarctic rocks: exposure and erosion history, Earth and Planetary Science Letters, vol.104, issue.2-4, pp.440-454, 1990. ,
DOI : 10.1016/0012-821X(91)90221-3
Cosmogenic10Be,26Al, and3He in olivine from Maui lavas, Earth and Planetary Science Letters, vol.98, issue.3-4, pp.263-266, 1990. ,
DOI : 10.1016/0012-821X(90)90028-V
Cosmic ray produced 10Be and 26Al in Antarctic rocks: exposure and erosion history, Earth and Planetary Science Letters, vol.104, issue.2-4, pp.440-454, 1991. ,
DOI : 10.1016/0012-821X(91)90221-3
In situ10Be-26Al exposure ages at Meteor Crater, Arizona, Geochimica et Cosmochimica Acta, vol.55, issue.9, pp.2699-2703, 1991. ,
DOI : 10.1016/0016-7037(91)90388-L
Production of 10Be and 26Al by cosmic rays in terrestrial quartz in situ and implications for erosion rates, Nature, vol.5, issue.6049, pp.134-136, 1986. ,
DOI : 10.1038/319134a0
Al in quartz from glacially polished rocks, Journal of Geophysical Research, vol.31, issue.B12, pp.17907-17915, 1989. ,
DOI : 10.1029/JB094iB12p17907
Secular variations in the production of cosmogenic isotopes in the Earth's atmosphere, Journal of Geophysical Research, vol.227, issue.2, pp.423-431, 1979. ,
DOI : 10.1029/JA084iA02p00423
THREEFOLD STONELINES IN SOUTHWESTERN NIGERIA, Soil Science, vol.123, issue.4, pp.249-257, 1977. ,
DOI : 10.1097/00010694-197704000-00006
Characteristics, distribution, and genesis of nodules and concretions in soils of the South-Western Upland of Nigeria, Soil Sci, issue.116, pp.282-291, 1973. ,
Rainfall patterns and the distribution of coals and evaporites in the Mesozoic and Cenozoic, Palaeogeography, Palaeoclimatology, Palaeoecology, vol.40, issue.1-3, 1982. ,
DOI : 10.1016/0031-0182(82)90085-2
Distribution des principaux type d'altération chimique à la surface du globe. Présentation d'une esquisse géographique, Rev. Géogr. Phys. Géol. Dynam, vol.10, issue.5, pp.457-470, 1968. ,
10Be in polar ice as a record of solar activity, pp.185-190, 1980. ,
Production of long-lived cosmogenic nuclei and their applications, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, vol.5, issue.2, pp.91-99, 1984. ,
DOI : 10.1016/0168-583X(84)90490-7
URL : https://hal.archives-ouvertes.fr/in2p3-00002534
The AMS facility at Gif-sur-Yvette: progress, perturbations and projects. Nuclear Instruments and Methods in, Physics Research B, B, vol.92, pp.43-46, 1994. ,
URL : https://hal.archives-ouvertes.fr/hal-01458902
Measurements of 10Be and 26Al with a tandetron AMS facility, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, vol.29, issue.1-2, pp.22-26, 1987. ,
DOI : 10.1016/0168-583X(87)90196-0
URL : https://hal.archives-ouvertes.fr/hal-01458909
Hematite and Goethite from Duricrusts Developed by Lateritic Chemical Weathering of Precambrian Banded Iron Formations, Minas Gerais, Brazil, Clays and Clay Minerals, vol.44, issue.1, pp.22-31, 1996. ,
DOI : 10.1346/CCMN.1996.0440102
Contribution à l'étude des "stone-lines en régions tropicale et équatoriale, Cahier O.R.S.T.O.M. série pédologie, pp.71-109, 1969. ,
Slip rates along faults estimated with cosmic-ray-exposure dates: Application to the Bogd fault, Geology, issue.11, pp.23-1019, 1995. ,
URL : https://hal.archives-ouvertes.fr/in2p3-00000610
The relationship between 10 Be and geomagnetic field strengh records in central North Atlantic sediments during the last 80 ka, Earth and Planetary Science Letters, issue.136, pp.551-557, 1995. ,
(Zaïre) Datation de deux "stone-lines" par palynologie: Kamoa et Haute Luilu, Geo-Eco-Trop, vol.11, issue.14, pp.171-183, 1987. ,
Archéologie préhistorique et processus de formation des "stone-lines" en Afrique Centrale (Congo-Brazzaville et zones périphériques), Geo-Eco-Trop, vol.20, pp.1-4, 1996. ,
Le remaniement des sols et la mise en place de la "stone-line, pp.113-128, 1969. ,
Radiogenic production of 10Be and 26Al in uranium and thorium ores: Implications for studying terrestrial samples containing low levels of 10Be and 26Al, Geochimica et Cosmochimica Acta, vol.53, issue.3, pp.709-716, 1989. ,
DOI : 10.1016/0016-7037(89)90013-6
Landslides and related phenomena. Columbia Geomorphic studies, 1938. ,
Cosmogenic dating ranging from 20 to 700 ka of a series of alluvial fan surfaces affected by the El Tigre fault, Argentina, Geology, vol.25, issue.11, pp.25-975, 1997. ,
DOI : 10.1130/0091-7613(1997)025<0975:CDRFTK>2.3.CO;2
URL : https://hal.archives-ouvertes.fr/hal-01458848
Stopping rate of negative cosmic-ray muons near sea level, Journal of Geophysical Research, vol.9, issue.28, pp.5351-5359, 1972. ,
DOI : 10.1029/JA077i028p05351
Weathering and erosion in the humid tropics. Physical and chemical weathering in geochemical cycles, pp.225-246, 1988. ,
Le profil d'altération du Bas-Congo (Kinshasa), Pédologie, issue.17, pp.60-105, 1967. ,
Determination of erosion rates with cosmogenic 26 Al. Nuclear Instruments and Methods in Physics Research, pp.317-320, 1994. ,
Le modelé des régions chaudes, forêts et savanes, 1965. ,
Rate controlling factors in the weathering of some ferromagnesian silicate minerals., Transactions, 13th congress of the intern, Society of Soil Science, pp.1107-1118, 1987. ,
Aspects de l'??volution morphologique r??cente de l'Ouest Africain, Annales de G??ographie, vol.68, issue.367, pp.68-193, 1959. ,
DOI : 10.3406/geo.1959.16306
???Laterite is not a soil but maybe a paleosol???, CATENA, vol.26, issue.3-4, pp.263-265, 1996. ,
DOI : 10.1016/0341-8162(95)00045-3
26 Al/ 10 Be in terrestrial impact glasses, Journal of non crystalline solids, vol.67, pp.1-3, 1984. ,
URL : https://hal.archives-ouvertes.fr/in2p3-00002009