Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-05T06:55:48.972Z Has data issue: false hasContentIssue false

The Role of Randomly Mixed-Layered Chlorite/Smectite in the Transformation of Smectite to Chlorite

Published online by Cambridge University Press:  28 February 2024

Lori Bettison-Varga
Affiliation:
Department of Geology, The College of Wooster, Wooster, Ohio 44691
Ian D. R. Mackinnon
Affiliation:
Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia QLD 4072, Australia
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Vesicular and groundmass phyllosilicates in a hydrothermally altered basalt from the Point Sal ophiolite, California, have been studied using transmission electron microscopy (TEM). Pore-filling phyllosilicates are texturally characterized as having coherent, relatively thick and defect-free crystals of chlorite (14 Å) with occasional 24-Å periodicities. Groundmass phyllosilicates are texturally characterized as 1) randomly oriented crystals up to 200 Å in width and 2) larger, more coherent crystals up to 1000 Å in width. Small crystallites contain predominantly 14-Å layers with some 24-Å units. Large crystals show randomly interlayered chlorite/smectite (C/S), with approximately 50% chlorite on average. Adjacent smectite-like layers are not uncommon in the groundmass phyllosilicates. Electron microprobe analyses show that Fe/Mg ratios of both groundmass and vesicular phyllosilicates are fairly constant.

Termination of brucite-like interlayers has been identified in some of the TEM images. The transformation mechanisms represented by these layer terminations are 1) growth of a brucite-like interlayer within smectite interlayer regions and 2) the dissolution and reprecipitation of elements to form chlorite layers. Both mechanisms require an increase in volume as smectite transforms to chlorite.

The data, combined with that from previously published reports, suggest that randomly interlayered C/S is a metastable phase formed in microenvironments with low water/rock ratios. Chlorite forms in microenvironments in the same sample dominated by higher water/rock ratios. The relatively constant number of Mg's in the structure (Mg#) of both structures indicates that in both microenvironments the bulk rock composition has influence over the composition of phyllosilicates.

Type
Research Article
Copyright
Copyright © 1997, The Clay Minerals Society

References

Abercrorabie, H.J. Hutcheon, I.E. Bloch, J.D. and de Caritat, P., 1994 Silica activity and the smectite-illite reaction Geology 22 539542 10.1130/0091-7613(1994)022<0539:SAATSI>2.3.CO;2.2.3.CO;2>CrossRefGoogle Scholar
Alt, J.C., Honnorez, J., Laverne, C. and Emmermann, R.. 1986. Hydrothermal alteration of a 1 km section through the upper oceanic crust, deep sea drilling project hole 504B: Mineralogy, chemistry, and evolution of seawater-basalt interactions. J Geophys Res 91:10,30910,335.CrossRefGoogle Scholar
Banfield, J.S. Bailey, W. and Barker, W.W., 1994 Polysomatism, polytypism, defect microstructures, and reaction mechanisms in regularly and randomly interstratified serpentine and chlorite Contrib Mineral Petrol 117 137150 10.1007/BF00286838.CrossRefGoogle Scholar
Beaufort, D. and Meunier, A., 1994 Saponite, corrensite, and chlo-rite-saponite mixed-layers in the Sancerre-Couy deep drillhole (France) Clay Miner 29 4761 10.1180/claymin.1994.029.1.06.CrossRefGoogle Scholar
Bettison, L.A. and Schiffman, P., 1988 Compositional and structural variations of phyllosilicates from the Point Sal ophiolite, California Am Mineral 73 6276.Google Scholar
Bettison-Varga, L. Mackinnon, I.D.R. and Schiffman, P., 1991 Integrated TEM, XRD, and electron microprobe investigation of mixed-layered chlorite-smectite from the Point Sal ophiolite, California J Metamorphic Geol 9 697710 10.1111/j.1525-1314.1991.tb00559.x.CrossRefGoogle Scholar
Bevins, R.E. Robinson, D. and Rowbotham, G., 1991 Compositional variations in mafic phyllosilicates from regional low-grade metabasites and application of the chlorite geother-mometer J Metamorphic Geol 9 711721 10.1111/j.1525-1314.1991.tb00560.x.CrossRefGoogle Scholar
Brigatti, M.F. and Poppi, L., 1984 Crystal chemistry of corrensite: A review Clays Clay Miner 32 391399 10.1346/CCMN.1984.0320507.CrossRefGoogle Scholar
Chang, H.K. Mackenzie, F.T. and Schoonmaker, J., 1986 Comparisons between the diagenesis of dioctahedral and triocta-hedral smectite, Brazilian offshore basins Clays Clay Miner 34 407423 10.1346/CCMN.1986.0340408.CrossRefGoogle Scholar
Cowley, J. and Moodie, A.F., 1957 The scattering of electrons by atoms and crystals. I. A new theoretical approach Acta Crystallogr 10 609619 10.1107/S0365110X57002194.CrossRefGoogle Scholar
Gallahan, W.E. and Duncan, R.A., 1994 Spatial and temporal variability in crystallization of celadonites within the Troodos ophiolite, Cyprus: Implications for low-temperature alteration of the oceanic crust J Geophys Res 99 31473161 10.1029/93JB02221.CrossRefGoogle Scholar
Guthrie, G.D. and Veblen, D.R., 1989 High resolution transmission electron microscopy of mixed-layer illite/smectite: Computer simulations Clays Clay Miner 37 111 10.1346/CCMN.1989.0370101.CrossRefGoogle Scholar
Helmhold, K.P. van der Kamp, P., McDonald, D.A. and Surdam, R.C., 1984 Diagenetic mineralogy and controls on albitization and laumontite formation in Palaeogene arkoses, Santa Ynez Mountains, California Clastic diagenesis. Am Assoc Petrol Geol Mem 239276.CrossRefGoogle Scholar
Hoffman, J. and Hower, J., 1979 Clay mineral assemblages as low grade metamorphic geothermometers: Application to the thrust faulted disturbed belt of Montana, USA Aspects of diagenesis. Soc Econ Paleontol Mineral Spec Publ 26 5579 10.2110/pec.79.26.0055.CrossRefGoogle Scholar
Hopson, C.A. Frano, C.J. and Pessagno, E.A. Jr. and Mattinson, J.M., 1975 Preliminary report and geologic guide to the Jurassic ophiolite near Point Sal, southern California Coast Geol Soc Ara Cordilleran Sec Guidebook to Field Trip .Google Scholar
Horton, D.G., 1985 Mixed-layer illite/smectite as a paleotemperature indicator in the Amethyst vein system, Creed district, Colorado, USA Contrib Mineral Petrol 91 171179 10.1007/BF00377764.CrossRefGoogle Scholar
Huang, W.-L. Longo, J.M. and Pevear, D.R., 1993 An experimentally derived kinetic model for smectite-to-illite conversion and its use as a geothermometer Clays Clay Miner 41 162177 10.1346/CCMN.1993.0410205.CrossRefGoogle Scholar
Inoue, A., 1985 Chemistry of corrensite: A trend in composition of trioctahedral chlorite/smectite during diagenesis J Coll Arts Sci, Chiba Univ B–18 6982.Google Scholar
Inoue, A., Schultz, L.G. van Ophen, H. and Mumpton, F.A., 1987 Conversion of smectite to chlorite by hydro-thermal and diagenetic alterations, Hokuroku Kuroko mineralization area, northeast Japan Proc Int Clay Conf Denver, CO. Bloomington, IN Clay Miner Soc 158164.Google Scholar
Inoue, A. and Utada, M., 1991 Smectite-to-chlorite transformation in thermally metamorphosed volcanoclastic rocks in the Kamikita area, northern Honshu, Japan Am Miner 76 628640.Google Scholar
Inoue, A.M. Utada, M. Negata, H. and Watanabe, T., 1984 Conversion of trioctahedral smectite to interstratified chlorite/smectite in Pliocene acidic pyroclastic sediments of the Ohyu district, Akita Prefecture, Japan Clay Sci Soc Jpn 6 103116.Google Scholar
Jiang, W.-T. and Peacor, D., 1994 Prograde transitions of corrensite and chlorite in low-grade pelitic rocks from the Gaspe Peninsula, Quebec Clays Clay Miner 42 497517 10.1346/CCMN.1994.0420501.CrossRefGoogle Scholar
Liou, J.G. Seki, Y. Guillemette, R.N. and Sakai, H., 1985 Compositions and parageneses of secondary minerals in the Onikobe geothermal system, Japan Chem Geol 49 120 10.1016/0009-2541(85)90143-3.CrossRefGoogle Scholar
Meunier, A. Inoue, A. and Beaufort, D., 1991 Chemiographic analysis of trioctahedral smectite-to-chlorite conversion series from the Ohyu Caldera, Japan Clays Clay Miner 39 409415 10.1346/CCMN.1991.0390410.CrossRefGoogle Scholar
Reynolds, R.C. Jr., 1985 NEWMOD©: A computer program for the calculation of one-dimensional diffraction patterns of mixed-layered clays Hanover, NH RC Reynolds, Jr.Google Scholar
Roberson, H.E., 1988 Random mixed-layer chlorite-smectite: Does it exist? [abstract] 25th Clay Miner Soc Annu Meet; Grand Rapids, MI 98.Google Scholar
Roberson, H.E., 1989 Corrensite in hydrothermally altered oceanic rocks [abstract] 26th Clay Miner Soc Annu Meet; Sacramento, CA 59.Google Scholar
Schiffman, P. Bettison, L.A. and Williams, A., 1986 Hydrothermal metamorphism of the Point Sal remnant, California Coast Range ophiolite Proc 5th Int Symp on Water-Rock Interactions 489492.Google Scholar
Schiffman, P. and Fridleifsson, G.O., 1991 The smectite-chlorite transition in drillhole NJ-15, Nesjavellir geothermal field, Iceland: XRD, BSE, and electron microprobe investigations J Metamorphic Geol 9 679696 10.1111/j.1525-1314.1991.tb00558.x.CrossRefGoogle Scholar
Schiffman, P. and Staudigel, H., 1995 The smectite to chlorite transition in a fossil seamount hydrothermal system: The basement complex of La Palma, Canary Islands J Metamorphic Geol 13 487498 10.1111/j.1525-1314.1995.tb00236.x.CrossRefGoogle Scholar
Shau, Y.-H. and Peacor, D., 1992 Phyllosilicates in hydrothermally altered basalts from DSDP hole 504B, leg 83-A TEM and AEM study Contrib Mineral Petrol 112 119133 10.1007/BF00310959.CrossRefGoogle Scholar
Shau, Y.-H. Peacor, D. and Essene, E., 1990 Corrensite and mixed-layer chlorite/corrensite in metabasalt from northern Taiwan: TEM/AEM, EPMA, XRD, and optical studies Contrib Mineral Petrol 105 123142 10.1007/BF00678980.CrossRefGoogle Scholar
Stadelmann, P., 1991 Simulation of HREM images and 2D CBED patterns using EMS software package. Software manual 12M-EPFI Lausanne Switzerland.Google Scholar
Veblen, D.R., 1980 Anthophyllite asbestos: Microstructures, intergrown sheet silicates, and mechanisms of fiber formation Am Mineral 65 10751086.Google Scholar
Veblen, D.R. and Buseck, P.R., 1980 Microstructures and reaction mechanisms in biopyriboles Am Mineral 65 599623.Google Scholar
Veblen, D.R. and Buseck, P.R., 1981 Hydrous pyriboles and sheet silicates in pyroxenes and uralites: Intergrowth, microstructures and reaction mechanisms Am Mineral 66 11071134.Google Scholar
Veblen, D.R. and Ferry, J.M., 1983 A TEM study of the biotite-chlorite reaction and comparison with petrologic observations Am Mineral 68 11601168.Google Scholar
Velde, B., 1977 Clays and clay minerals in natural and synthetic systems Amsterdam Elsevier.Google Scholar