Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-26T08:30:24.210Z Has data issue: false hasContentIssue false
  • English
  • Français

Palaeoweathering in slates from the Iberian Hercynian Massif (Spain): investigation by TEM of clay mineral signatures

Published online by Cambridge University Press:  09 July 2018

M. A. Vicente ,
F. Elsass ,
E. Molina  and
M. Robert
M. A. Vicente
Affiliation:
IRNA/CSIC, Apd 257, 37080 Salamanca, Spain
F. Elsass
Affiliation:
INRA, Route de Saint-Cyr, 78026 Versailles Cedex, France
E. Molina
Affiliation:
Dpt Geologia, Universidad Salamanca, Spain
M. Robert
Affiliation:
INRA, Route de Saint-Cyr, 78026 Versailles Cedex, France
Get access Rights & Permissions [Opens in a new window]

Abstract

Palaeoweathering profiles are widely represented in the Iberian meseta. Transmission electron microscopy (TEM) and analytical electron microscopy (AEM) were used to describe the mechanisms governing the processes involved in the formation of one of these weathering profiles developed over slates of the Iberian Hercynian Massif. Three well-differentiated weathering stages were distinguished, based upon well-defined mineralogical signatures characteristic of primary or secondary minerals. The lower stage is characterized by fresh green slates composed of Fe-chlorite, micas, quartz and feldspars. The soft slates represent an intermediate weathering stage. A confined environment has permitted the development of smectite from the different primary phyllosilicates, both by neoformation of montmorillonite and transformation into beidellite. In the upper part of the profile, the red slates are the most weathered. A tropical or subtropical climate has resulted in the formation of kaolinite and abundant iron oxides over several metres. The present study demonstrates that the three identified weathering stages were formed under the same climatic conditions. Such ‘toposequences’ are developed at the present time in tropical areas (Bocquier, 1971).

Type
Research Article
Information
Clay Minerals , Volume 32 , Issue 3 , September 1997 , pp. 435 - 451
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Blanco, J.A., Corrochano, R., Montigny R & Thuizat, R. (1982) Sur l'age du début de la sédimentation dans le bassin tertiaire du Duero (Espagne). Attribution au Paléocène par datation isotopique des alunites de l'unité inférieure. C. R. Acad. Sci. Paris, 595, 559–562.Google Scholar
Bisdom, E.B.A. (1967) Micromorphology of a weathered granite near the Ria de Arosa (NW Spain). Leidse Geol. Med. 37, 34–67.Google Scholar
Bocquier, G. (1971) Genèse et évolution de deux toposéquences de sols tropicaux du Tchad. lnterprdtation biogéodynamique. Thèse ès Sci., Univ. Strasbourg, Mém. ORSTOM, 62, 350 pp.Google Scholar
Bustillo, M.A. & Martin Serrano, A. (1980) Caracterisación y significado de las rocas siliceas y ferruginosas del Paleoceno de Zamora. Tecniterrae, 36, 1–16.Google Scholar
Deer, W.A., Howie, R.A. & Zussman, J. (1965) Sheet silicates. In: Rock Forming Minerals, vol. 3, Longmans, Green & Co Ltd, London.Google Scholar
Espejo, R. (1987) Estudio del perfit edáfico y caracterisación de las superficies tipo Rana del sector Canamero-Horcajo de los Montes. Tesis doctoral, ETS Ingenieros Agrónomos, Madrid, Spain.Google Scholar
Garcia Abbad, F.J. & Martín Serrano, A. (1980) Precisiones sobre la génesis y cronologia de los relieves apalachianos del Macizo Hespérico (Meseta central espafiola). Estudios Geológicos, Madrid, 36, 391–40t,Google Scholar
Garcia Talegon, J., Molina, E. & Vicente, M.A. (1991) Weathering processes in granites. Proc. 7th Euroclay Confi Dresden, 405-409.Google Scholar
Gomez de Llarena, J. (1916) Bosquejo geograficogeologico de los Montes de Toledo. Trabajos deI Museo Nacional de Ciencias Naturales (Serie Geol.), 15, 74 pp.Google Scholar
Kubiena, W.L. (1954) Uber reliktboden in Spanien. Pp. 213–224 in: Angewandte t∼flanzensociologie. Festschrift Aichiger, Klagenjurth. Google Scholar
Martin Serrano, A. (1988) E1 relieve de la regién occidental Zamorana. La evolución geomorfológica de un borde del Macizo Hespérico. Ed. Estudios Zamoranos “Florián Camps”, CSIC/Diputación de Zamora, 311 pp.Google Scholar
Martinez Lope, M.J., Garcia Gonzalez, M.T. & Molina, E. (1995) Relationships between geomorphology and paleoweatherings on the Hercynian basement in central Spain. A mineralogical and geochemical approach. Rev. Soc. Geol. EspaSa, 8, 127–136.Google Scholar
Molina, E. & Blanco, J.A. (1980) Quelques précisions sur l'altération du Massif Hercynien espagnol. C.R. Acad. Sci., Paris, 290, 1293–1296.Google Scholar
Molina, E., Garcia Gonzalez, M.T. & Espejo, R. (1991) Study of paleoweathering on the spanish Hercynian basement. Montes de Toledo, Central Spain. Catena 18, 345–354.CrossRefGoogle Scholar
Parga, J.R. (1969) Sistemas de fracturas tardihercinicas del Macizo Hespérico. Trabajos del Lab. Xeol. de Laxe, 37, 1–15.Google Scholar
Peacor, D.R. (1992a) Analytical electron microscopy: X-ray analysis. Pp. 113–140 in: Minerals and Reactions at the Atomic Scale: Transmission Electron Microscopy. (Buseck, P.R., editor). Rev. Mineralogy, (Ribbe, P.H., editor), 27, Mineralogical Society of America, Washington D.C.Google Scholar
Peacor, D.R. (1992b) Diagenesis and low-grade metamorphism of shales and slates. Pp∼ 335–376 in: Minerals and Reactions at the Atomic Scale: Transmission Electron Microscopy. (Buseck, P.R., editor). Rev. Mineralogy, (Ribbe, P. H., editor), 27, Mineralogical Society of America, Washington, D.C. Google Scholar
Riedel, W. (1973) Bodengeographie des Kastilischen und Portugiesischen Hauptscheidegebirges. Mitt. Geogr Ges. Hamburg, 62, 161 pp.Google Scholar
Riedet, W. & Schmidt-Norenz, R. (1978) Micromorphological investigations of relict soils of the Cordillera Central (Spain). Proc. 5th Int. Meeting Soil Micromorphology, Granada, 2, 1187–1198.Google Scholar
Robert, M. (1973) The experimental transformation of mica toward smectite: relative importance of total charge and tetrahedral substitution. Clays Clay Miner. 21, 167–174.Google Scholar
Solé Sabarís, L. & Llopis Llado, N. (1952) Peninsula Iberica. in: EspaBa, Geografía Física. Vol. 1 “Geografía de Espana y Portugal”, (de Terán, M., editor) Montanery Simén, Barcelona, 549 pp.Google Scholar
Tessier, D. & Pedro, G. (1987) Mineralogical characterization of 2:1 clays in soils: Importance of the clay texture. Proc. Int. Clay Conf Denver, 78-84.Google Scholar
Vicente, A., Molina, E. & Garcia Rodriguez, P. (1987) Sequence of the processes of geochemical weathering in the northern piedmont of the Central System (Salamanca, Spain), Proc. 6th Meet. European Clay Groups, Sevilla, 564–566.Google Scholar
Vicente, M.A., Molina, E. & Espejo, R. (1991) Clays in paleoweathering processes: study of a typical weathering profile in the Hercynian basement in the Montes de Toledo (Spain). Clay Miner. 26, 81–90.Google Scholar
Virgili, C., Paquet, H. & Millot, G. (1974) Altdration du soubassement de la couverture Permo-Triassique en Espagne. Bull. Groupe fr. Argiles 2, 277–285.Google Scholar
Wilson, A.D. (1960) The micro-determination of ferrous iron in silicate minerals by a volumetric and a colorimetric method. Analyst, 85, 823–827.Google Scholar