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Mineralogy and Genetic Relationships of Tonstein, Bentonite, and Lignitic Strata in the Eocene Yegua Formation of East-Central Texas

Published online by Cambridge University Press:  02 April 2024

A. L. Senkayi ,
J. B. Dixon ,
L. R. Hossner ,
M. Abder-Ruhman  and
D. S. Fanning
A. L. Senkayi
Affiliation:
Department of Soil and Crop Sciences, Texas Agricultural Experiment Station Texas A&M University, College Station, Texas 77843
J. B. Dixon
Affiliation:
Department of Soil and Crop Sciences, Texas Agricultural Experiment Station Texas A&M University, College Station, Texas 77843
L. R. Hossner
Affiliation:
Department of Soil and Crop Sciences, Texas Agricultural Experiment Station Texas A&M University, College Station, Texas 77843
M. Abder-Ruhman
Affiliation:
Department of Soil and Crop Sciences, Texas Agricultural Experiment Station Texas A&M University, College Station, Texas 77843
D. S. Fanning*
Affiliation:
Department of Soil and Crop Sciences, Texas Agricultural Experiment Station Texas A&M University, College Station, Texas 77843
*
1Department of Agronomy, University of Maryland, College Park, Maryland 20742.
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Abstract

A kaolinite-rich bed (tonstein) and an associated bentonite in the upper part of Yegua Formation at College Station, east-central Texas, were formed by in situ weathering processes in a late Eocene swamp. X-ray powder diffraction, infrared spectroscopy, petrographic studies, and scanning and transmission electron microscopy not only show that dioctahedral smectite and coarsely crystalline kaolinite are the dominant minerals in the bentonite and tonstein, respectively, but that cryptocrystalline halloysite and kaolinite are localized along the weathering front (transitional zone) between the tonstein and the bentonite. As weathering progressed, the cryptocrystalline minerals gradually recrystallized to yield the coarse books and vermicular growths of kaolinite characteristic of the tonstein.

Small amounts of cristobalite, sanidine, and euhedral zircon crystals with liquid or gaseous inclusions accord with the formation of the bentonite by alteration of volcanic ash. Clinoptilolite in the lignitic layer and sandstone below the bentonite probably formed from ions that were released during alteration of the volcanic materials to smectite, but clinoptilolite in the tonstein and overlying strata appear to have formed after kaolinization of the bentonite.

Резюме

Резюме

Пласт, обогащенный каолинитом (тонштейн) и ассоциированный бентонит в верхней части формации Егуа в Коледж Стейшин в восточно-центральном Тексасе, формировались путем виутри-пластовых процессов эрозии в болоте позднего эоцена. Рентгеновская порошковая дифракция, инфракрасная спектроскопия, петрографические исследования, а также сканнинговая и трансмисионная микроскопия указывали не только на то, что диоктаэдрический смектит и грубо кристаллический каолинит являются главными минералами в бентоните и тонштейне, соответственно, но что крип-токристаллический галлуазит и каолинит расположены вдоль фронта эрозии (переходная зона) между тонштейном и бентонитом. Когда эрозия прогрессировала, криптокристаллические минералы постепенно рекристаллизировались, чтобы производить грубые книгоподобные и червеобразные росты каолинита, характеристические для тонштейна. Небольшие количества кристобалита, санидина и идиоморфных кристаллов циркона с жидкими или газовыми включениями согласовывались с формированием бентонита путем изменения вулканического пепела. Клиноптилолит в слое бурого угля и песчаника ниже бентонита формировался, вероятно, из ионов, которые выделялись во премя видоизменения вулканических материалов в смектит, но клиноптилолит в тонштейне и перекрывающих породах, вероятно, образовывался после каолинизации бентонита. [E.G.]

Resümee

Resümee

Eine Kaolinit-reiche Lage (Tonstein) und ein damit zusammenhängender Bentonit im oberen Teil der Yegua Formation bei College Station, Ostzentraltexas, wurden durch in situ Verwitterungsprozesse in einem späteozänen Moor gebildet. Röntgenpulverdiffraktometrische, infrarotspektroskopische und petrographische sowie raster- und transmissionselektronenmikroskopische Untersuchungen zeigten nicht nur, daß dioktaedrischer Smektit und grobkristallisierter Kaolinit die vorherrschenden Minerale in dem Bentonit bzw. in dem Tonstein sind, sondern daß auch kryptokristalliner Halloysit und Kaolinit entlang der Verwitterungsfront (Übergangszone) swischen Tonstein und Bentonit auftreten. Wenn die Verwitterung fortgeschritten ist, rekristallisierten die kryptokristallinen Minerale allmählich und führten zu dem groben bücherförmigen und wurmähnlichen Wachstum von Kaolinit, das für den Tonstein charakteristisch ist.

Geringe Gehalte an Cristobalit, Sanidin, und idiomorphen Zirkonkristallen mit flüssigen oder gasförmigen Einschlüssen stimmen mit der Bildung des Bentonites durch Umwandlung von vulkanischer Asche überein. Klinoptilolit in den Lignitlagen und im Sandstein unter dem Bentonit wurde wahrscheinlich aus Ionen gebildet, die während der Umwandlung des vulkanischen Materials zu Smektit freigesetzt wurden. Der Klinoptilolit in dem Tonstein und den darüberliegenden Schichten scheint nach der Kaolinisierung des Bentonites gebildet worden zu Scin. [U.W.]

Résumé

Résumé

Un lit riche en kaolinite (tonstein) et une bentonite associée dans la partie supérieure de la Formation Yegua à College Station, centre-est du Texas, ont été formés par un procédé d'altération in situ dans un marais du Bas Eocène. La diffraction aux rayons-X, la spectroscopic infrarouge, des études petrographiques, et la microscopie électronique et à transmission d’électrons montrent non seulement que la smectite dioctaèdrale et la kaolinite grossièrement cristallisée sont les minéraux dominants dans la bentonite et la tonstein respectivement, mais que l'halloysite cryptocristalline et la kaolinite sont localisées le long du front d'altération (zone de transition) entre la tonstein et la bentonite. Au fur et à mesure de la progression de l'altération, les minéraux cryptocristallins se sont graduellement recristallisés pour donner les livres grossiers et les croissances vermiculaires caractéristiques de la tonstein.

De petites quantités de cristobalite, de sanidine, et de cristaux euhédraux de zircon avec des inclusions liquides ou gazeuses s'accordent avec la formation de la bentonite par altération de la cendre volcanique. La clinoptilite dans la couche lignitique et dans le grès en dessous de la bentonite s'est probablement formée à partir d'ions qui avaient été relâchés pendant l'altération de matériaux volcaniques en smectite, mais la clinoptilolite dans la tonstein et les strates susjacentes semble avoir été formée après la kaolinisation de la bentonite. [D.J.]

Keywords

BentoniteClinoptiloliteKaoliniteLigniteSmectiteTonsteinWeathering
Type
Research Article
Information
Clays and Clay Minerals , Volume 32 , Issue 4 , August 1984 , pp. 259 - 271
Copyright
Copyright © 1984, The Clay Minerals Society

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References

Askenasy, P. E., Dixon, J. V. and McKee, T. R., 1973 Spheroidal halloysite in a Guatemalan soil Soil Sci. Soc. Amer. Proc. 37 799–803.CrossRefGoogle Scholar
Berg, R. R. and Berg, R. R., 1970 Stratigraphy of the Claiborne Group Claiborne Outcrops in the Brazos Valley, Southwest Texas 13–16.Google Scholar
Bernas, V., 1968 A new method for decomposition and comprehensive analysis of silicates by atomic absorption spectrometry Anal. Chem. 40 1682–1686.CrossRefGoogle Scholar
Berry, L. G., 1973 Powder Diffraction File for Minerals Pennsylvania Joint Committee on Powder Diffraction Standards, Swarth-more.Google Scholar
Brindley, G. W., Brindley, G. W. and Brown, G., 1980 Order-disorder in clay mineral structures Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 125–195.CrossRefGoogle Scholar
Brown, G., Brindley, G. W. and Brown, G., 1980 Associated minerals Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 361–410.CrossRefGoogle Scholar
Carr, C.E., 1973 Gravimetric determination of soil carbon using the LECO induction furnace. J. Sci. Food Agric. 24 1091–1095.CrossRefGoogle Scholar
Dixon, J. B. and McKee, T. R., 1974 Internal and external morphology of tubular and spheroidal halloysite particles Clays & Clay Minerals 22 127–137.CrossRefGoogle Scholar
Farmer, V. S. and Farmer, V. C., 1974 The layer silicates The Infrared Spectra of Minerals London Mineralogical Society 331–363.CrossRefGoogle Scholar
Grim, R. E. and Giiven, N., 1978 Bentonites Amsterdam Elsevier 126–137.Google Scholar
Hay, R.L., Sand, L. B. and Mumpton, F. A., 1978 Geologic occurrence of zeolites Natural Zeolites: Occurrence, Properties and Use New York Pergamon Press, Elmsford 135–145.Google Scholar
Innes, R. P. and Pluth, D. J., 1970 Thin section preparation for petrographie and microprobe analysis Soil Sci. Soc. Amer. Proc. 34 484–485.CrossRefGoogle Scholar
Jackson, M. L., 1974 Soil Chemical Analysis—Advanced Course Wisconsin Madison.Google Scholar
Kaiser, W. R. (1974) Texas lignite: near-surface and deep-basin resources: Texas Bur. Econ. Geol. Rept. Invest. 79, 70 pp.Google Scholar
Keller, W. D. and Hanson, R. F., 1975 Dissimilar fabrics by scan electron microscopy of sedimentary versus hydro-thermal kaolins in Mexico Clays & Clay Minerals 23 201–204.CrossRefGoogle Scholar
Kirkman, J. H., 1981 Morphology and structure of halloysite in New Zealand tephras Clays & Clay Minerals 29 1–9.CrossRefGoogle Scholar
Loughnan, F. C., 1978 Flint clays, tonsteins and the ka-olinite clay rock facies Clay Miner. 13 387–400.CrossRefGoogle Scholar
Mathews, A. L. (1950) Geology of Brazos County, Texas: Texas A&M College, Eng. Exp. Station, Res. Rept. 14, 14 pp.Google Scholar
Millot, G., 1970 Geology of Clays New York Springer-Verlag.CrossRefGoogle Scholar
Moore, L. R., 1964 The in situ formation and development of some kaolinite macrocrystals Clay Miner. Bull. 5 338–352.CrossRefGoogle Scholar
Morgan, D. J., Highley, D. E., Bland, D. J., Mortland, M. M. and Farmer, V. S., 1979 A montmorillonite, kaolinite association in the Lower Cretaceous southeast England Proc. Int. Clay Confi, Oxford, 1979 Amsterdam Elsevier 301–310.Google Scholar
Mumpton, F. A. and Ormsby, W. C., 1976 Morphology of zeolites in sedimentary rocks by scanning electron microscopy Clays & Clay Minerals 24 1–23.CrossRefGoogle Scholar
Norrish, K., 1968 Some phosphate minerals of soils Trans. 9th Int. Congr. Soil Sci, Adelaide, Australia 11 713–723.Google Scholar
Pevear, D. R., Williams, V. E. and Mustoe, G. E., 1980 Kaolinite, smectite and K-rectorite in bentonites: relation to coal rank at Tulameen, British Columbia Clays & Clay Minerals 28 241–254.CrossRefGoogle Scholar
Price, N. B. and Duff, P. M. D., 1969 Mineralogy and chemistry of tonsteins from carboniferous sequences in Great Britain Sedimentology 13 45–69.CrossRefGoogle Scholar
Roberson, H. E., 1964 Petrology of Tertiary bentonites of Texas J. Sediment. Petrol. 34 401–411.Google Scholar
Saigusa, M., Shogi, S. and Kato, T., 1978 Origin and nature of halloysite in ando soils from Towada tephra, Japan Geoderma 20 115–129.CrossRefGoogle Scholar
Spears, D. A. and Kanaris-Sotiriou, R., 1979 A geochemical and mineralogical investigation of some British and other European tonstein Sedimentology 26 407–425.CrossRefGoogle Scholar
Williamson, I. A., 1970 Tonsteins—their nature, origins and uses Mining Mag. 122 119–125.Google Scholar
Wright, T. L., 1968 X-ray and optical study of alkali feldspar, Pt. 2 Amer. Mineral. 53 88–104.Google Scholar
Zhou, Y., Ren, Y. and Bohor, B. F., 1982 Origin and distribution of tonsteins in Late Permian Coal seams of southwestern China. Int. J. Coal Geol. 2 49–77.CrossRefGoogle Scholar