A comparative analyses of microstructures from Late Jurassic diamictic units, near Helmsdale, northeast Scotland and a Pleistocene diamicton from near Milton, southern Ontario, Canada – a differential diagnostic method of sediment typing using micromorphology
Abstract Micromorphology is used to examine and compare a Late Jurassic diamictite from northeast Scotland with a Pleistocene diamict from southern Ontario, Canada in order to test if a statistical difference between diamicts can be recognized and used to separate differing types of diamicts/diamict...
| Published in: | Netherlands Journal of Geosciences - Geologie en Mijnbouw |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2009
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0016774600001001 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016774600001001 |
| Summary: | Abstract Micromorphology is used to examine and compare a Late Jurassic diamictite from northeast Scotland with a Pleistocene diamict from southern Ontario, Canada in order to test if a statistical difference between diamicts can be recognized and used to separate differing types of diamicts/diamictites. The diamictites from Scotland have been ascribed to various depositional agencies occurring in several distinctly differing terrestrial and marine palaeoenvironments. In contrast, the Pleistocene diamicton is regarded as a subglacial till. Both diamicts appear remarkably similar visually and contain many corresponding features such as macrostructures, and exotic and fractured subangular to subrounded clasts. Micromorphology is used to re-examine these diamicts/diamictites at the microscopic level to detect if the palaeoenvironments within which they were deposited can be ascertained. In this paper a quantitative assessment of microstructures using micromorphology is developed. Comparative statistical analyses of these diamicts, using micromorphological features, reveals that the Jurassic diamictites are non-glacigenic, non-terrestrial and most likely deposited within a marine environment as a result of subaquatic debris mass movement, while, in contrast, the Pleistocene diamicts were most likely subglacial tectomicts deposited beneath the active base of the Laurentide Ice Sheet. |
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