New insights into smectite illitization: A zoned K-bentonite revisited

  title={New insights into smectite illitization: A zoned K-bentonite revisited},
  author={Douglas K. Mccarty and Boris A. Sakharov and Victor A. Drits},
  journal={American Mineralogist},
  pages={1653 - 1671}
Abstract The illitization reaction in a thick K-bentonite bed located in upper Cretaceous marine shale in the Montana disturbed belt was studied by X-ray diffraction, chemical analysis, and thermal gravimetric analysis. Modeling of the experimental XRD patterns from oriented clay specimens in air-dried and glycolated states shows that at each sample location in the bentonite bed a mixture of R0 illite-smectite (I-S) and R1 I-S coexist. Each of these phases in all samples consists of the same or… Expand
New insights into microbial smectite illitization in the Permo-Triassic boundary K-bentonites, South China
Abstract Microbially mediated smectite illitization has been extensively demonstrated in laboratory experiments. Despite occasional observations in geological environments, the transformationExpand
A reinvestigation of smectite illitization in experimental hydrothermal conditions: Results from X-ray diffraction and transmission electron microscopy
Abstract The hydrothermal reactivity of the <1 μm fraction, K-saturated SWy-2 Wyoming low-charge montmorillonite was studied in the 250-400 °C temperature range with reactions lasting between 5 andExpand
Regional illitization in bentonite beds from the East Slovak Basin based on isotopic characteristics (K-Ar, δ18O and δD) of illite-type nanoparticles
Abstract Nanometre-sized illite-type crystals extracted from mixed-layer illite-smectite of cored bentonite beds from the East Slovak Basin were studied to investigate timing, duration andExpand
Characterization of smectite to NH4-illite conversion series in the fossil hydrothermal system of Harghita Bãi, East Carpathians, Romania
Abstract Ammoniumillite (NH4-I) is one of the alteration products present in a breccia structure in the fossil hydrothermal system from Harghita Bãi (East Carpathians), Romania. A series fromExpand
Ammonium vermiculite in schists from the Betic Cordillera (Spain)
Abstract NH4-bearing phases from pre-Permian schists of the Internal Zones of the Betic Cordillera (Spain) have been characterized by X‑ray diffraction, differential thermal analysis andExpand
Technique for determination of the content of smectite layers in the dispersed dioctahedral K-bearing micaceous minerals
A technique was developed to determine the low contents of smectite layers in the dispersed dioctahedral K-bearing micaceous minerals of the illite-glauconite composition. To implement thisExpand
XRD-TEM-AEM comparative study of n-alkylammonium smectites and interstratified minerals in shallow-diagenetic carbonate sediments of the Basque-Cantabrian Basin
Abstract The validity of the application of the n-alkylammonium method to carbonate-rich lithologies was checked by means of a double comparison: First, the method was applied to samples studied byExpand
Cesium, a water-incompatible, siloxane-complexed cation in Earth’s upper crust
Despite similarities in geochemical behavior, Cs and Rb concentrate in the upper continental crust (UCC) preferentially to K. Illite, a K-depleted dioctahedral mica occurring in large proportions inExpand
Anatomy of a metabentonite: Nucleation and growth of illite crystals and their coalescence into mixed-layer illite/smectite
Abstract The illite layer content of mixed-layer illite/smectite (I/S) in a 2.5 m thick, zoned, metabentonite bed from Montana decreases regularly from the edges to the center of the bed. TraditionalExpand
Determination of Minor Contents of Smectite Layers in the Dispersed Dioctahedral K-bearing Micaceous Minerals of the Illite, Aluminoceladonite, and Glauconite Composition
A theoretically substantiated technique has been elaborated for the precise determination of minor contents of smectite layers in the dioctahedral mixed-layer structures with a disordered alternationExpand


Illite-smectite structural changes during metamorphism in black Cambrian Alum shales from the Baltic area
Abstract Illite-smectite (I-S) from Cambrian black shale of both early diagenetic and anchimetamorphic grade was investigated to determine the mechanism of the clay transformation. The layerExpand
Early clay diagenesis in Gulf Coast sediments: New insights from XRD profile modeling
Samples from different depths in the Oligocene Frio formation (offshore Gulf of Mexico) were studied by X-ray diffraction (XRD), thermal analyses, and scanning electron microscopy. The experimentalExpand
The structure and diagenetic transformation of illite-smectite and chlorite-smectite from North Sea Cretaceous-Tertiary chalk
Abstract Illite-smectite (I-S) mixed-layer minerals from North Sea oil fields and a Danish outcrop were investigated to determine the detailed structure and the diagenetic clay transformation. ClayExpand
Characterization of mixed-layer illite-smectite from bentonites using microscopic, chemical, and X-ray methods: Constraints on the smectite-to-illite transformation mechanism
Abstract We studied mixed-layer illite-smectite (I/S) (<1 or 0.5 μm size fractions) in 28 diagenetic bentonite samples, Pliocene to Ordovician in age, from different locations in North America andExpand
Phase relations among smectite, R1 illite-smectite, and illite
Abstract A variety of smectitic and illitic clays were studied by TEM and AEM, following expansion by L.R. White resin, to define phase relations for clay minerals undergoing digenesis and low-gradeExpand
Sequential structure transformation of illite-smectite-vermiculite during diagenesis of Upper Jurassic shales from the North Sea and Denmark
Abstract For mixed-layer clay fractions from the North Sea and Denmark, X-ray diffractograms have been recorded for specimens saturated with Mg, Ca, Na and NH4, both airdry and intercalated withExpand
Diagenetic smectite-to-illite transition in clay-rich sediments: A reappraisal of X-ray diffraction results using the multi-specimen method
Smectite illitization is a common mineralogical reaction occurring during the burial diagenesis of clay-rich sediments and shales, and has thus attracted sustained interest over the last fifty years.Expand
Model for K-bentonite formation: Evidence from zoned K-bentonites in the disturbed belt, Montana
Thirty-four K-bentonites from the Marias River Formation (Upper Cretaceous) in the Montana disturbed belt have been studied in detail. A 2.5-m-thick K-bentonite is zoned mineralogically andExpand
Phase relations among smectite , R 1 illite-smectite , and illite
A variety of smectitic and illitic clays were studied by TEM and AEM, following expansion by L.R. White resin, to define phase relations for clay minerals undergoing digenesis and low-gradeExpand
Structural and chemical heterogeneity of illite-smectites from Upper Jurassic mudstones of East Greenland related to volcanic and weathered parent rocks
Illite-smectites (I-S) in one Upper Jurassic mudstone core from East Greenland were investigated to determine their structural and crystal-chemical features and to find the relation between theseExpand