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Characterization and Origin of 1:1 Phyllosilicates within Peloids of the Recent, Holocene and Miocene Deposits of the Congo Basin

Published online by Cambridge University Press:  28 February 2024

A. Wiewióra ,
B. Lacka  and
P. Giresse
A. Wiewióra
Affiliation:
Institute of Geological Sciences, Polish Academy of Sciences, al. Zwirki i Wigury 93, 02-089 Warszawa, Poland
B. Lacka
Affiliation:
Institute of Geological Sciences, Polish Academy of Sciences, al. Zwirki i Wigury 93, 02-089 Warszawa, Poland
P. Giresse
Affiliation:
Laboratoire de Sédimentologie et Géochimie Marines, Université de Perpignan, 52, Avenue de Villeneuve, 66860 Perpignan, France
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Abstract

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The grey-green peloids from the Miocene period to Recent fine-grained deposits on the continental shelf close to Congo-Zaîire River mouth were studied by X-ray transmission diffractometry (XRD), SEM and by EDAX. The peloids have multiphase heterogenous mineral composition. Their most important constituents are detrital minerals like kaolinite, quartz, goethite, 7 Å phases with d(001) ≈ 7.3 Å, and in more maturated grains—nontronite. The d(060) values were used to estimate the general composition of phyllosilicate phases to compare with the composition determined by EDAX. It has been found that d(060) equal to 1.504 Å is common for Fe3+-bearing kaolinite, which is quite abundant for the Recent peloids. The d(060) equal to 1.535 Å and 1.55 Å is characteristic for the di-trioctahedral and trioctahedral 1:l phases, which are abundant within the more evolved Miocene peloids. Nontronite is characterized by d(060) equal to 1.524 Å within concordance with its highly ferrous composition, and partly by its potassic interlayer. It shows cabbage-like nannostructures proving neoformational origin of this mineral in the marine environment.

It has been shown that areas of the low sedimentation rate within the Congo Basin were favorable for the mineral changes and neoformation. For the Holocene vertical profile, we observed levels of slower sedimentation rates. The evolution is expressed by the disappearance of kaolinite at the expense of other 7 Å phases and nontronite. Although more advanced stages of maturation of the studied phases were observed in older peloids (104 to 107 y), one cannot detect a linear relationship of these processes with burial.

Keywords

1:1 phyllosilicateChemical compositionNontronitePeloidsX-ray diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 44 , Issue 5 , October 1996 , pp. 587 - 598
Copyright
Copyright © 1996, The Clay Minerals Society

References

Amouric, M., Parron, C., Casalini, L. and Giresse, P.. 1995. A (1: 1) 7 A phase and its transformation in Recent sediments: an HRTEM and AEM study. Clays Clay Miner 43: 446–454.CrossRefGoogle Scholar
Bailey, S.W.. 1988. Odinite, a new dioctahedral-trioctahedral Fe3+ rich 1: 1 clay mineral. Clay Miner 23: 237–247.CrossRefGoogle Scholar
Bhattacharyya D., P.. 1983. Origin of berthierine in ironstones. Clays Clay Miner 31: 173–182.CrossRefGoogle Scholar
Brigatti, M.F.. 1985. Relationships between composition and structure in Fe-rich smectites. Clay Miner 18: 177–186.CrossRefGoogle Scholar
Brindley, G.W.. 1980. Order-disorder in clay mineral structures. Ch. 2. In: Brindley, G.W., Brown, G., editors. Crystal structures of clay minerals and their X-ray identification. London: Mineralogical Society. P 125–195.CrossRefGoogle Scholar
Brindley, G.W.. 1982. Chemical composition of berthierine—a review. Clays Clay Miner 30: 152–155.CrossRefGoogle Scholar
Cotter, E.. 1992. Diagenetic alteration of chamosite minerals to ferric oxide in oolitic limestone. J Sedim Petrol 62: 54–60.Google Scholar
Drits, V.A.. 1992. Interviews with the clay scientists. CMS News, February 1992. p 9.Google Scholar
Giresse, P.. 1985. Le fer et les glauconies au large du fleuve Congo. Strasbourg: Sci Géol 38: 293–322.Google Scholar
Giresse, P., Wiewióra, A. and Lacka, B.. 1987. Migration des éléments et minéralogenèse dans les grains verts Récents au large de l'embouchure du Congo. Archiw Mineral 42: 5–30.Google Scholar
Giresse, P., Wiewióra, A. and Lacka, B.. 1988. Mineral phases and processes within green peloids from two recent deposits near the Congo River mouth. Clay Miner 23: 447–458.CrossRefGoogle Scholar
Giresse, P., Oualembo, P., Wiewióra, A., Lacka, B. and Zawidzki, P.. 1992. Compositions polyphases des grains verts du Bassin du Congo; Comparaison des depots Recents, Holocenes (103-104 ans) et Miocenes (107 ans). Archiw Mineral 47: 17–50.Google Scholar
Ijima, A. and Matsumoto, R.. 1982. Berthierine and chamosite in coal measures of Japan. Clays Clay Miner 30: 264–274.CrossRefGoogle Scholar
Jepson, W.B.. 1988. Structural iron in kaolinites and in associated ancillary minerals. In: Stucki, J.W., Goodman, B.A., Schwertmann, U., editors. Iron in soils and clay minerals. Dordrecht: Reidel D. P 467–536.CrossRefGoogle Scholar
Nahon, D.. 1981. Modes de répartition des métaux dans les solutions solides des altèrations tropicales; application aux concentrations supergènes ferrugineuses. In: Nahon, D., editor. Valorisation des ressources du sous-sol, Orléans: Doc BRGM 47. 254–264.Google Scholar
Odin, G.S.. 1985. La “verdine”, faciès granulaire vert, marin et côtier, distinct de la glauconie: distribution actuelle et composition. Paris: CR Acad Sc 301, 2: 105–108.Google Scholar
Odin, G.S.. 1988. The verdine facies from the lagoon off New-Caledonia. In: Odin, G.S., editor. Green marine clays. Developments in Sedimentology. Amsterdam: Elsevier. p 57–81.CrossRefGoogle Scholar
Odin, G.S. and Sen Gupta, B.K.. 1988. Geological significance of the verdine facies. In: Odin, G.S., editor. Green marine clays. Developments in Sedimentology 45. Amsterdam: Elsevier. P 205–219.CrossRefGoogle Scholar
Parron, C.. 1989. Voies et mécanismes de cristallogenèse des minèraux argileux ferrifères en milieu marin. Le processus de glauconitisation: èvolutions minèrales, structurales et géochimiques. [PhD Thesis]. Aix-Marseille: Sc Univ. III. 411 p.Google Scholar
Stucki, J.W.. 1988. Structural iron in smectites. In: Stucki, J.W., Goodman, B.A., Schwertmann, U., editors. Iron in soils and clay minerals. Dordrecht: Reidel D. p 625–675.CrossRefGoogle Scholar
Velde, B.. 1989. Phyllosilicate formation in berthierine peloids and Iron oolites. In: Young, T.P., Taylor, W.E.G., editors. Phanerozoic Ironstones. London: Geological Society 46. p 3–8.Google Scholar
Vila, E., Ruiz-Amil, A. and Martin de Vidales, J.L.. 1988. Computer programs for X-ray powder diffraction analysis. Madrid: Internal Report CSIC. 17 p.Google Scholar
Wiewióra, A.. 1990a. Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition. I. The mica group. Clay Miner 25: 73–81.CrossRefGoogle Scholar
Wiewióra, A.. 1990b. Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition. III. Serpentine-kaolin group. Clay Miner 25: 93–98.CrossRefGoogle Scholar