caa a22 4500 465791905 CHVBK 20180323112027.0 cr unu---uuuuu 170327e19901201xx s 000 0 eng 10.1007/BF00306406 doi (NATIONALLICENCE)springer-10.1007/BF00306406 A transmission electron microscope study of white mica crystallite size distribution in a mudstone to slate transitional sequence, North Wales, UK [Elektronische Daten] [R. Merriman, B. Roberts, D. Peacor] High-resolution transmission electron microscopy (HRTEM) measurements of the thickness of white mica crystallites were made on three pelite samples that represented a prograde transition from diagenetic mudstone though anchizonal slate to epizonal slate. Crystallite thickness, measured normal to (001), increases as grade increases, whereas the XRD measured 10 Å peak-profile, the Kubler index, decreases. The mode of the TEM-measured size population can be correlated with the effective crystallite size N(001) determined by XRD. The results indicate that the Kubler index of white mica crystallinity measures changes in the crystallite size population that result from prograde increases in the size of coherent X-ray scattering domains. These changes conform to the Scherrer relationship between XRD peak broadening and small crystallite size. Lattice ‘strain' broadening is relatively unimportant, and is confined to white mica populations in the diagenetic mudstone. Rapid increases in crystallite size occur in the anchizone, coincident with cleavage development. Changes in the distribution of crystallite thickness with advancing grade and cleavage development are characteristic of grain-growth by Ostwald ripening. The Kubler index rapidly loses sensitivity as an indicator of metapelitic grade within the epizone. Springer-Verlag, 1990 Merriman R. British Geological Survey, Keyworth, NG12 5GG, Nottingham, UK aut Roberts B. Department of Geology, Birkbeck College, Malet Street, WC1 1EX, London, UK aut Peacor D. Department of Geological Sciences, University of Michigan, 48109, Ann Arbor, Michigan, USA aut Contributions to Mineralogy and Petrology Springer-Verlag 106/1(1990-12-01), 27-40 0010-7999 106:1<27 1990 106 410 https://doi.org/10.1007/BF00306406 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00306406 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Merriman R. British Geological Survey, Keyworth, NG12 5GG, Nottingham, UK aut NATIONALLICENCE 700 1- Roberts B. Department of Geology, Birkbeck College, Malet Street, WC1 1EX, London, UK aut NATIONALLICENCE 700 1- Peacor D. Department of Geological Sciences, University of Michigan, 48109, Ann Arbor, Michigan, USA aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 106/1(1990-12-01), 27-40 0010-7999 106:1<27 1990 106 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer