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The Kübler Index in Late Diagenetic to Low-Grade Metamorphic Pelites: A Critical Comparison of Data From 10 Å and 5 Å Peaks

Published online by Cambridge University Press:  01 January 2024

Stefano Battaglia ,
Leonardo Leoni  and
Franco Sartori
Stefano Battaglia
Affiliation:
Istituto di Geoscienze e Georisorse, (Consiglio Nazionale delle Ricerche), Area S. Cataldo, Via Moruzzi n.1, Pisa 56124, Italy
Leonardo Leoni*
Affiliation:
Istituto di Geoscienze e Georisorse, (Consiglio Nazionale delle Ricerche), Area S. Cataldo, Via Moruzzi n.1, Pisa 56124, Italy Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria n. 53, Pisa 56126, Italy
Franco Sartori
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria n. 53, Pisa 56126, Italy
*
*E-mail address of corresponding author: [email protected]
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Abstract

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A set of 99 samples covering the whole range of low- and very low-grade metamorphic conditions has been used to compare Kübler index (KI) values measured on the illite 10 Å reflection (KI10 Å) with those obtained from the 5 Å reflection (KI5 Å). Evaluation of peak widths have been carried out both graphically on the recorded peak profiles from chart-strip X-ray diffraction (XRD) patterns and with the WINFIT computer program (Krumm, 1996) on fitted and decomposed profiles. All the measurements were performed both on air-dried and glycolated preparations. The data collected show that in the rock samples where illite is associated with significant amounts of I-S interstratified minerals, and/or K/Na intermediate micas, paragonite and other interfering phases, full width at half-maximum (FWHM) measurements on the 5 Å peak in fitted and decomposed XRD profiles from glycolated mounts give more reliable KI values than those obtained from the 10 Å peak. This is because of the easier and more complete de-summation of the illite second reflection from the contributions of all the interfering phases. In each sample population in which the rocks have the same metamorphic grade, KI5 Å values from fitted and decomposed profiles show much lower scattering in comparison with KI10 Å values and appear consistent with the values measured in lithologies without interfering phases.

The relationship between KI10 Å and KI5 Å appears very close to a 1:1 linear relationship; nevertheless, the conversion from KI5 Å to KI10 Å through the appropriate equation (KI10 Å = KI5 Å × 0.965 + 0.023°2θ) is recommended in order to avoid a small, but systematic, error.

In the range from late diagenesis to middle anchizone, where several phases may give diffraction effects interfering with illite peaks, the proposed procedure (i.e. FWHM measurements on the 5 Å peak in fitted and decomposed XRD profiles from glycolated mounts) seems to allow better estimates of the metamorphic grade than those obtained through traditional KI measurements.

Keywords

10 Å and 5 Å PeaksAir-dried and EG-solvated PreparationsFitted or Fitted and Decomposed PeaksIlliteKübler IndexLate DiagenesisLow-grade MetamorphismMetapelites
Type
Correction
Information
Clays and Clay Minerals , Volume 52 , Issue 1 , February 2004 , pp. 85 - 105
Copyright
Copyright © 2004, The Clay Minerals Society

Footnotes

An erratum to this article is available online at https://doi.org/10.1346/0009860041570730.

References

Árkai, P., Mottana, A. Sassi, F.P. Thompson, J.B. and Guggenheim, S., (2002) Phyllosilicates in very low-grade metamorphism: Transformation to micas Micas: Crystal Chemistry and Metamorphic Petrology Washington, D.C. Mineralogical Society of America 463–478 10.1515/9781501509070-016.CrossRefGoogle Scholar
Árkai, P. Sassi, F.P. and Sassi, R., (1995) Simultaneous measurements of chlorite and illite crystallinity: a more reliable tool for monitoring low- to very low-grade metamorphism in metapelites. A case study from the Southern Alps (NE Italy) European Journal of Mineralogy 7 1115–1128 10.1127/ejm/7/5/1115.CrossRefGoogle Scholar
Carosi, R., Leoni, L., Montomoli, C. and Sartori, F. (2003) Very low-grade metamorphism in the Tuscan Nappe, Northern Apennines, Italy: relationships between deformation and metamorphic indicators in the La Spezia mega-fold. Schweizerische Mineralogische und Petrographische Mitteilungen, 83, (in press).Google Scholar
Frey, M. and Frey, M., (1987) Very low-grade metamorphism of clastic sedimentary rocks Low temperature Metamorphism Glasgow & London Blackie 9–58.Google Scholar
Frey, M. and Robinson, D., (1999) Low-grade Metamorphism Oxford, UK Blackwell Science 313 pp.Google Scholar
Guggenheim, S. Bain, D.C. Bergaya, F. Brigatti, M.F. Drits, V.A. Eberl, D.D. Formoso, M.L.L. Galán, E. Merriman, R.J. Peacor, D.R. Stanjek, H. and Watanabe, T., (2002) Report of the Association International pour l’Étude des Argiles (AIPEA) nomenclature Committee for 2001: order, disorder and crystallinity in phyllosilicates and the use of the ‘crystallinity index’ Clays and Clay Minerals 50 406–409 10.1346/000986002760833783.CrossRefGoogle Scholar
Kisch, H.J., (1990) Calibration of the anchizone: A critical comparison of illite “crystallinity” scales used for definition Journal of Metamorphic Geology 8 31–46 10.1111/j.1525-1314.1990.tb00455.x.CrossRefGoogle Scholar
Kisch, H.J., (1991) Illite crystallinity: recommendations on sample preparation, X-ray diffraction settings, and inter-laboratory samples Journal of Metamorphic Geology 9 665–670 10.1111/j.1525-1314.1991.tb00556.x.CrossRefGoogle Scholar
Kisch, H.J. Frey, M. and Frey, M., (1987) Appendix: Effect of sample preparation on the measured 10 Å peak width of illite (illite “crystallinity”) Low-temperature Metamorphism Glasgow & London Blackie 301–304.Google Scholar
Kretz, R., (1983) Symbols for rock-forming minerals American Mineralogist 68 277–279.Google Scholar
Krumm, S., (1992) Illitkristallinität als Indikator schwacher Metamorphose. Metodische Untersuchungen, regionale Anwendungen und Vergleiche mit anderen Parametern Erlanger Geologische Abhandlungen 120 1–75.Google Scholar
Krumm, S., (1996) WINFIT 1.2: version of November 1996 (The Erlangen geological and mineralogical software collection) of “WINFIT 1.0: a public domain program for interactive profile-analysis under WINDOWS”. XIII Conference on Clay Mineralogy and Petrology, Praha, 1994 Acta Universitatis Carolinae Geologica 38 253–261.Google Scholar
Krumm, S. and Buggisch, W., (1991) Sample preparation effects on illite crystallinity measurement: Grain-size gradation and particle orientation Journal of Metamorphic Geology 9 671–677 10.1111/j.1525-1314.1991.tb00557.x.CrossRefGoogle Scholar
Krumm, S. Kisch, H.J. and Warr, L.N., (1994) Inter-laboratory study of the effects of sample preparation on illite “crystallinity”: A progress report. XIII Conference on Clay Mineralogy and Petrology, Praha 1994 Acta Universitatis Carolinae Geologica 38 263–270.Google Scholar
Kübler, B., (1964) Les argiles, indicateurs de métamorphisme Revue de l’Institut Français du Pétrole 19 1093–1112.Google Scholar
Kübler, B., (1967) La cristallinité de l’illite et les zones tout à fait superieures du metamorphisme Etages tectoniques, Colloque de Neuchâtel 1966 Neuchâtel, Switzerland Editions de la Baconnière 105–121.Google Scholar
Kübler, B. and Lagache, M., (1984) Les indicateurs des transformations physiques et chimiques dans la diagenèse, température et calorimétrie Thermobarométrie et Barométrie Géologiques Paris Société Française de Minéralogie et Cristallographie 489–596.Google Scholar
Lanson, B., (1990) Mise en évidence des mécanismes de transformation des interstratifiés illite/smectite au cours de la diagenèse Paris, France Université de Paris 6-Jussieu PhD thesis.Google Scholar
Lanson, B., (1997) Decomposition of experimental X-ray di ffraction patterns (profile fitting): a convenient way to study clay minerals Clays and Clay Minerals 45 132–146 10.1346/CCMN.1997.0450202.CrossRefGoogle Scholar
Lanson, B. and Besson, G., (1992) Characterization of the end of smectite-to-illite transformation: Decomposition of X-ray patterns Clays and Clay Minerals 40 40–52 10.1346/CCMN.1992.0400106.CrossRefGoogle Scholar
Lanson, B. and Champion, D., (1991) The I/S-to-illite reaction in the late stage diagenesis American Journal of Science 291 473–596 10.2475/ajs.291.5.473.CrossRefGoogle Scholar
Leoni, L., (2001) New standardized illite crystallinity data from low- to very low-grade metamorphic rocks (Northern Apennines, Italy) European Journal of Mineralogy 13 1109–1118 10.1127/0935-1221/2001/0013-1109.CrossRefGoogle Scholar
Leoni, L. Marroni, M. Sartori, F. and Tamponi, M., (1996) Metamorphic grade in metapelites of the Internal Liguride Units (Northern Apennines, Italy) European Journal of Mineralogy 8 35–50 10.1127/ejm/8/1/0035.CrossRefGoogle Scholar
Lezzerini, M. Sartori, F. and Tamponi, M., (1995) Effect of amount of material used on sedimentation slides in the control of illite ‘crystallinity’ measurements European Journal of Mineralogy 7 819–823 10.1127/ejm/7/4/0819.CrossRefGoogle Scholar
Montomoli, C. Ruggieri, G. Boiron, M.C. and Cathelineau, M., (2001) Pressure fluctuations during uplift of the Northern Apennines (Italy): a fluid inclusion study Tectonophysics 341 121–139 10.1016/S0040-1951(01)00197-4.CrossRefGoogle Scholar
Moore, D.M. and Reynolds, R.C., (1997) X-ray Diffraction and the Identification and Analysis of Clay Minerals Oxford-New York Oxford University Press 378 pp.Google Scholar
Mullis, J. Rahn, M.K. Schwer, P. de Capitani, C. Stern, W.B. and Frey, M., (2002) Correlation of fluid inclusion temperatures with illite “crystallinity” data and clay mineral chemistry in sedimentary rocks from the external part of the Central Alps Schweizerische Mineralogische und Petrographische Mitteilungen 82 325–340.Google Scholar
Nieto, F. and Sánchez-Navas, A., (1994) A comparative XRD and TEM study of the physical meaning of the white mica ‘crystallinity’ index European Journal of Mineralogy 6 611–621 10.1127/ejm/6/5/0611.CrossRefGoogle Scholar
Reutter, K.J. Teichmüller, M. Teichmüller, R. and Zanzucchi, G., (1980) Le ricerche sulla carbonificazione dei frustoli vegetali nelle rocce clastiche, come contributo ai problemi di paleogeotermia e tettonica nell’Appennino Settentrionale Memorie della Società Geologica Italiana 21 111–126.Google Scholar
Robinson, D. Warr, L.N. and Bevins, R.E., (1990) The illite “crystallinity” technique: A critical appraisal of its precision Journal of Metamorphic Geology 8 333–344 10.1111/j.1525-1314.1990.tb00476.x.CrossRefGoogle Scholar
Środoń, J., (1984) X-ray powder diffraction identification of illitic materials Clays and Clay Minerals 32 337–349 10.1346/CCMN.1984.0320501.CrossRefGoogle Scholar
Stern, W.B. Mullis, J. Rahn, M. and Frey, M., (1991) Deconvolution of the first “illite” basal reflection Schweizerische Mineralogische und Petrographische Mitteilungen 71 453–462.Google Scholar
Velde, B. and Lanson, B., (1993) Comparison of I/S transformations and maturity of organic matter at elevated temperatures Clays and Clay Minerals 41 178–183 10.1346/CCMN.1993.0410206.CrossRefGoogle Scholar
Wang, H. Stern, W.B. and Frey, M., (1995) Deconvolution of the X-ray “Illite” 10-Å complex: A case study of Helvetic sediments from eastern Switzerland Schweizerische Mineralogische und Petrographische Mitteilungen 75 187–199.Google Scholar
Warr, L.N., (1996) Standardized clay mineral crystallinity data from the very low-grade metamorphic facies rocks of southern New Zealand European Journal of Mineralogy 8 115–127 10.1127/ejm/8/1/0115.CrossRefGoogle Scholar
Warr, L.N. and Rice, A.H.N., (1994) Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data Journal of Metamorphic Geology 12 141–152 10.1111/j.1525-1314.1994.tb00010.x.CrossRefGoogle Scholar
Weaver, C.E., (1960) Possible uses of clay minerals in search for oil Bulletin of the American Association of Petroleum Geologists 44 1505–1518.Google Scholar