Exploring for the Future- X-Ray Diffraction (XRD) data release of sedimentary rocks in the South Nicholson Basin and Isa Superbasin, Northern Australia

X-ray diffraction analysis was used to identify the clay minerals present in fourteen subsoil samples that were selected to represent some more important clay-bearing deposits in British Columbia. The clay mineralogy of the subsoils varied considerably but montmorillonitic clay minerals tended to predominate in the water-laid deposits of the south and illite in the soil parent materials of the Interior Plains region of the northeastern part of the Province.

Download Full-text

Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications

Clay Minerals ◽

10.1180/0009855054020165 ◽

2005 ◽

Vol 40 (2) ◽

pp. 191-203 ◽

Cited By ~ 15

Author(s):

F. Khormali ◽

A. Abtahi ◽

H. R. Owliaie

Keyword(s):

Electron Microscopy ◽

Upper Cretaceous ◽

Sedimentary Rocks ◽

X Ray Diffraction ◽

Humid Climate ◽

X Ray ◽

Late Mesozoic ◽

Southern Iran ◽

Transmission Electron

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.

Download Full-text

The conversion of smectite to illite during diagenesis: evidence from some illitic clays from bentonites and sandstones

Mineralogical Magazine ◽

10.1180/minmag.1985.049.352.10 ◽

1985 ◽

Vol 49 (352) ◽

pp. 393-400 ◽

Cited By ~ 93

Author(s):

P. H. Nadeau ◽

M. J. Wilson ◽

W. J. McHardy ◽

J. M. Tait

Keyword(s):

Organic Molecules ◽

Thickness Distribution ◽

Sedimentary Rocks ◽

Exchangeable Cations ◽

Diffraction Effect ◽

X Ray Diffraction ◽

X Ray ◽

Depth Of Burial ◽

Particle Thickness ◽

Scanning Electron

AbstractDiagenetic illitic clays from seven North American bentonites of Ordovician, Devonian, and Cretaceous ages and from three subsurface North Sea sandstones of Permian and Jurassic ages have been examined by X-ray diffraction (XRD) and transmission and scanning electron microscopy (TEM and SEM). XRD indicates that the clays from the bentonites are randomly and regularly interstratified illite/smectites (I/S) with 30–90% illite layers, whereas the clays from the Jurassic and Permian sandstones are regularly interstratified I/S, with 80–90% illite layers, and illite respectively. TEM of shadowed materials shows that randomly interstratified I/S consists primarily of mixtures of elementary smectite and ‘illite’ particles (10 and 20Å thick respectively) and that regularly interstratified I/S and illite consist mainly of ‘illite’ particles 20–50 Å thick and > 50 Å thick respectively. Regularly interstratified I/S from bentonites and sandstones are similar with regard to XRD character and particle thickness distribution. These observations can be rationalized if the interstratified XRD character arises from an interparticle diffraction effect, where the smectite interlayers perceived by XRD, result from adsorption of exchangeable cations and water or organic molecules at the interfaces of particles generally < 50Å thick. A neoformation mechanism is proposed by which smectite is converted to illite with increasing depth of burial in sedimentary rocks, based on dissolution of smectite particles and the precipitation/growth of ‘illite’ particles occurring within a population of thin phyllosilicate crystals.

Download Full-text

Bosoite, a new silica clathrate mineral from Chiba Prefecture, Japan

Mineralogical Magazine ◽

10.1180/mgm.2020.91 ◽

2020 ◽

pp. 1-8

Author(s):

Koichi Momma ◽

Takuji Ikeda ◽

Toshiro Nagase ◽

Takahiro Kuribayashi ◽

Chibune Honma ◽

...

Keyword(s):

Crystal Structure ◽

Sedimentary Rocks ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

Average Model ◽

Guest Molecules ◽

Calculated Density ◽

X Ray ◽

Cell Parameters ◽

Chiba Prefecture

Abstract Bosoite (IMA2014-023) is a new silica clathrate mineral containing hydrocarbon molecules in its crystal structure. Bosoite can be considered structurally as a silica analogue of the structure-H gas hydrate, where guest molecules are trapped in cage-like voids constructed of the host framework. The mineral occurs in the Miocene tuffaceous sedimentary rocks at Arakawa, Minami-boso City, Chiba Prefecture, Japan. Bosoite is hexagonal, and it crystallises as an epitaxial intergrowth on chibaite crystals, with the {0001} of bosoite parallel to octahedral {111} form of chibaite. Crystals are colourless and transparent with vitreous lustre. The calculated density is 2.04 g/cm3. The empirical formula (based on 2 O apfu and guest molecules assumed as CH4) is Na0.01(Si0.98Al0.02)Σ1.00O2⋅0.50CH4; the end-member formula is SiO2⋅nC x H2x+2. Bosoite has the space group P6/mmm, with the unit-cell parameters a = 13.9020(3) Å, c = 11.2802(2) Å, V = 1887.99(6) Å3 and Z = 34. The crystal structure of bosoite was refined by single-crystal X-ray diffraction and converged to R1 = 4.26% for the average model and R1 = 2.96% for the model where all oxygen sites are split.

Download Full-text