...G. C. Capitani; E. Schingaro; M. Lacalamita; E. Mesto; F. Scordari Abstract A transmission electron microscopy (TEM) investigation was undertaken in order to elucidate the nature of the structural disorder in a tobelite specimen from the sedimentary rocks of the Armorican sandstones (western France...

... with decreasing NH 4 contents (tobelite, NH 4 -bearing white mica, and K-micas), probably through three successive processes: deuteric alteration, prograde reactions, and retrogressive reactions. The presence of N in cordierite is interpreted to be due to the transfer of the NH 4 , initially contained in biotite...

...,OD) 2 , where x = 0.0–3.0, y = 0.0–3.0, and the muscovite–tobelite series, (d) [K 1–A (NH 4 ,ND 4 ) A ]Al 3 Si 3 O 10 (OH,OD) 2 , where A = 0.0–1.0, indicate that there is a complete solid-solution in each series. In the 200–50 cm −1 far-infrared region, four kinds of bands are observed: two bands...

...Ernesto Mesto; Fernando Scordari; Maria Lacalamita; Emanuela Schingaro Abstract The crystal structures of tobelite and NH 4 + -rich muscovite from the sedimentary rocks of the Armorican sandstones (Brittany, France) have been solved for the first time by single-crystal X-ray diffraction...

..., in addition, tobelite, which comprises some of the detrital grains and strongly masks the illite crystallinity values. Tobelite has been identified only in the upper thrust slices, suggesting that changes in the detrital input is primarily responsible for the disappearance of tobelite at the transition from...

...-feldspar–buddingtonite, muscovite–tobelite series, and quartz. The run products were characterized by electron microprobe, powder X-ray diffraction with Rietveld analysis, and infrared spectroscopy. It can be shown that complete solid solution exists for both series for temperatures at least above 400 °C...

...Guy L. Hovis; Daniel Harlov; Matthias Gottschalk Abstract Enthalpies of solution of the NH 4 + -bearing minerals buddingtonite (NH 4 AlSi 3 O 8 feldspar) and tobelite [NH 4 Al 2 (AlSi 3 O 10 ) (OH) 2 mica] have been measured in 20.1 wt% hydrofluoric acid (HF) at 50°C. Utilizing additional HF...

...Mainak Mookherjee; Simon A.T. Redfern; Ming Zhang; Daniel E. Harlov Abstract Orientational order-disorder behavior of NH 4 + is a well-established phenomenon in certain ammonium halides and ammonium salts. Anticipating similar behavior of ammonium in the interlayer site of tobelite, synthetic ND 4...

... simultaneously with the diagenetic transformation of I-S. We demonstrate a link between the two reactions: NH 3 released from kerogen during maximum oil generation is fixed as NH 4 + in the NH 4 -bearing mica or tobelite layers formed from smectite or vermiculite layers in I-S, in a diagenetic interval which we...

... minerals include for each sample two mixed-layer phases consisting of pyrophyllite, margarite, paragonite, tobelite, illite, smectite and vermiculite layers. The main, 80 m thick intrusion resulted in the formation of pyrophyllite, margarite, paragonite and tobelite layers. However, the tobelite layers...

..., one of which contains 0.05 and the other 0.25 smectite (S) interlayers. The first phase does not change during metamorphism. In the second phase, 0.20 S are converted to tobelite (T) layers through fixation of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage...