The micromorphology of unconsolidated sediments

This paper aims to describe the use of thin sections/micromorphology in the sedimentology of unconsolidated sediments. It provides examples of the use of thin sections in a variety of sedimentary environments, from fault gouge, through caves and volcanics to aeolian, fluviatile, marine, periglacial and glacial. It demonstrates that in the latter three fields the use of micromorphology is relatively widespread and that in glacial sedimentology it has revolutionised our way of thinking about subglacial sediments. Although micromorphology has been mainly descriptive so far, methods of quantification observations are demonstrated. Some of the important aspects of micromorphology are its use for microstratigraphy and the possibility of relating observations to documented processes thereby allowing a more robust sedimentological interpretation of modern and ancient sediments.

Eemian lagoonal sediments with agglutinated forams, note smooth inner walls. This illustrates the fine detail that can be observed in thin sections from unlithified sediments. Sample Mi.618 from the North Sea, water depth 40 m, sample depth 25.55 m bsf; plane light; horizontal field of view (hfov) 4.5 mm.Figure optionsDownload high-quality image (254 K)Download as PowerPoint slide