Abstract
Naturally occurring ammonium illites have been discovered in black shales surrounding a stratiform base metal deposit in the DeLong Mountains, northern Alaska. Infrared spectra of the samples exhibit pronounced absorption at 1430 cm−1, the resonant-banding frequency for NH4+ coordinated in the illite interlayer. X-ray powder diffraction characteristics of the ammonium illites include an expanded d(001) spacing, with values as large as 10.16 Å, and ratios for I001/I003 and I002/I005 of about 2. Infrared analyses of physical mixtures of NH4Cl with a standard illite, and comparisons with synthetic ammonium micas indicate significant substitution (>50%) of NH4+ for K+ in the illite interlayer position. Nitrogen determinations on two ammonium illites after removal of carbonaceous matter gave values of 1.48 wt. % NH4+ and 1.44 wt. % NH4+. A survey of more than 150 different shale horizons indicates that the NH4+ content of the illites increases in proximity to the stratiform base metal mineralization.
Резюме
Натурально выступающие аммониевые иллиты были открыты в черных сланцеватых глинах, окружающих основной металлический осадок в горах ДеЛонга в северной Аласке. Инфракрасные спектры образцов указывают на значительную абсорбцию при 1430 см−1, частоте резонансной полосы NH4+, координированного в иллитовой прослойке. Характеристики рентгеновской порошковой дифракции аммониевых иллитов включают увеличенное расстояние d(001), co значениями, достигающими 10,16 Å а также отношениями I001/I003 и I002/I005 порядка 2. Инфракрасные анализы физических смесей NH4Cl со стандартным иллитом и сравнения с синтетическими аммониевыми слюдами указывают на значительную подстановку (>50%) иона NH4+ вместо иона K+ в межслойной области иллита. Определение количества азота в двух аммониевых иллитах после удаления углистой среды привело к величинам 1,48% веса NH4+ и 1,44% веса NH4+. Исследование более, чем 150 различных ярусов сланцевых глин показывает, что количество NH4+ в иллитах увеличивается в поблизости основной металлической минерализации. [E.C.]
Resümee
Natürlich auftretende Ammonium-Illite wurden in den Schwarzschiefern gefunden, die eine schichtförmige Erzlagerstätte in den Delong Mountains, Nord Alaska, umgeben. Die Infrarotspektren der Proben zeigen eine deutliche Absorption bei 1430 cm−1, d.h. die Resonanzfrequenz von NH4+, das in die Illitzwischenschicht eingebaut ist. Die Röntgenpulverdiffraktometerdiagramme der Ammonium-Illite zeigen einen aufgeweiteten d(001) Abstand, mit Werten um 10,16 Å und I001/I003 bzw. I002/I005 Verhältnissen von etwa 2. Infrarotuntersuchungen an mechanischen Gemengen aus NH4Cl und einem Standard Illit und Vergleiche mit synthetischen Ammonium-Glimmern deuten auf eine beträchtliche Substitution (>50%) von NH4+ für K+ auf den Zwischenschichtplätzen des Illit hin. Stickstoffbestimmungen an zwei Ammonium-Illiten nach der Entfernung von kohlenstoffhaltigen Substanzen ergaben Werte von 1,48 Gew.-% NH4+ bzw. 1,44 Gew.-% NH4+. Untersuchungen von mehr als 150 verschiedenen Schieferhorizonten deuten darauf hin, daß der NH4+-Gehalt der Illite mit zunehmender Nähe an die Metall-Mineralisation ansteigt. [U.W.]
Résumé
Des illites ammonium de provenance naturelle ont été découvertes dans des argilites noires entourant un dépôt stratiforme d’un métal de base dans les montagnes DeLong en Alaska du nord. Des spectres infrarouges des échantillons exhibent une adsorption prononcée à 1430 cm−1, la fréquence des liaisons resonantes pour NH4+ coordonné dans l’intercouche de l’illite. Les caractéristiques de diffraction poudrée aux rayons-X des illites ammonium comprennent un espacement d(001) élargi, avec des valeurs atteignant 10,16 Å, et des proportions pour I001/I003 et I002/I005 d’à peu près 2. Des analyses infrarouges de mélanges physiques de NH4Cl avec une illite standard, et des comparaisons avec des micas ammonium synthétiques indiquent une substitution significative (>50%) de NH4+ pour K+ dans la position intercouche illite. Des déterminations nitrogène sur deux illites ammonium après l’enlèvement de matière carbonacée ont donné des valeurs de 1,48 wt. % NH4+ et 1,44 wt. % NH4+. Un relevé de plus de 150 horizons argilite différents a indiqué que le contenu en NH4+ des illites accroit à proximité de la minéralisation stratiforme du métal de base.
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Sterne, E.J., Reynolds, R.C. & Zantop, H. Natural Ammonium Illites from Black Shales Hosting a Stratiform Base Metal Deposit, Delong Mountains, Northern Alaska. Clays Clay Miner. 30, 161–166 (1982). https://doi.org/10.1346/CCMN.1982.0300301
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DOI: https://doi.org/10.1346/CCMN.1982.0300301