|Title||Mineralogy of the ceramic clays and shales of the Atlantic provinces / La minéralogie des argiles et des schistes argileux à céramique des provinces de l'Atlantique|
|Licence||Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences.|
|Author||Dean, R S|
|Source||Canada Centre for Mineral and Energy Technology, Scientific Bulletin CM 75-8, 1975, 97 pages, https://doi.org/10.4095/328286 Open Access|
|Publisher||Energy, Mines and Resources Canada|
|Media||paper; on-line; digital|
|Province||New Brunswick; Newfoundland and Labrador; Nova Scotia; Prince Edward Island|
|NTS||1; 2; 10; 11; 12A; 12B; 12G; 12H; 12I; 12J; 12P; 20; 21A; 21B; 21G; 21H; 21I; 21J; 21N; 21O; 21P; 22A; 22B; 22C|
|Area||Island of Newfoundland|
|Lat/Long WENS|| -69.0833 -52.0000 51.7500 43.0000|
|Subjects||mineralogy; industrial minerals; regional geology; stratigraphy; surficial geology/geomorphology; Science and Technology; Nature and Environment; ceramic clays; shale, commodity; x-ray diffraction
analyses; mica; illite; silicates; chlorite; vermiculite; smectite; kaolin; feldspar; plagioclase; sediments; clays; bedrock geology; lithology; sedimentary rocks; shales; metamorphic rocks; schists; slates; Avalon Platform; Phanerozoic; Cenozoic;
Quaternary; Mesozoic; Cretaceous; Paleozoic; Permian; Carboniferous; Pennsylvanian; Mississippian; Ordovician; Cambrian|
|Illustrations||tables; location maps; spectra|
|Released||1975 05 01; 2021 04 23|
|Abstract||Twenty-nine samples of shales and surficial clays from the Atlantic Provinces were analysed by X-ray diffraction. The results were combined with published mineralogical data in order to examine regional
and stratigraphic clay mineral distribution patterns. Sampling inadequacies have been discussed.|
Dioctahedral clay mica (illite), identified in all samples, was the most abundant layer silicate mineral. With the exception of the apparently
hydrothermally altered clay from Middleton, Nova Scotia, the ordered (layer stacking) fraction of all illites consisted mostly or entirely of the 2M1 polymorph, the 1M variety being either greatly subordinate or absent. The highest concentrations of
2M1 mica were found in surficial clays which had apparently been derived from schists or slates, and in the slightly metamorphosed shale from Summerside, Newfoundland. The illites within the lower Paleozoic shales of the Avalon Platform,
Newfoundland, showed an apparent crystallite thinning similar to that observed in certain soils.
With the exception of the kaolinitic Cretaceous clays and two weathered or altered Pennsylvanian shales, trioctahedral chlorite was identified in all
samples, either as a component in mixed-layer systems or as an unmixed phase. The greatest concentration of chlorite was found in the surficial clays. Dioctahedral (aluminous interlayer) chlorite was recognized as a component of mixed-layer systems
within the Cretaceous kaolinitic clays.
Kaolin occurred in one of the Avalon Platform shales, and in all samples of Pennsylvanian age, including the Pennsylvanian-Permian transition beds on Prince Edward Island. The highest concentration of kaolin
was found within the Cretaceous Shubenacadie and Musquodoboit clays of central Nova Scotia.
Vermiculite and/or smectite was identified in all unmetamorphosed Paleozoic or Mesozoic shales or clays, and in some surficial clays. The expandable layers
occurred as components of mixed-layer systems interstratified with illite or chlorite rather than as unmixed phases. Certain mixed-layer systems were found to assume a uniform basal spacing when water-saturated.
The greatest concentrations of
feldspar were encountered within the surficial clays. With the exception of the Antigonish, Nova Scotia, shale and the Pennsylvanian-Permian transition beds on Prince Edward Island, the Pennsylvanian and (less certainly) upper Mississippian shales
were found to contain little feldspar. In most samples, plagioclase was considerably more abundant than K-feldspar.
Evidence suggests that many of the older clay mineral analyses may be inaccurate or incomplete.