A novel methodological approach for thin-section description and its application to periglacially disturbed Pleistocene deposits from Danbury, Essex, UK

Abstract

Although micromorphological terminology has been evolving since 1960, there have been few attempts to create a systematic approach to the description of thin-sections which would serve as a guiding tool for inexperienced researchers, students, and all new to the field of micromorphology. In this paper we present a novel, decision tree based systematic approach for thin-section description. This new approach attempts to unify micromorphological descriptions of Quaternary deposits, regardless of the character of the deposit and the purpose of the analysis.

In this research project, named ‘Hidden Ice Worlds’, the micromorphology of an 8 m thick sequence of periglacially disturbed deposits from the Royal Oak Pit, Danbury hill, Essex, UK is described. This sequence is situated on the eastern side of Danbury hill, at c. 50 m OD. Based on micromorphological analyses, a new hypothesis for the evolution of this sequence is presented. Multiple phases of physical reworking associated with freezing and thawing of the deposit, subsequent to Elsterian (Anglian) glaciation (480-420 ka BP) is proposed as the main process responsible for the evolution of the sequence. As periglacially derived deposits are usually removed from such elevated locations on hill' slopes, inversion of the topography is proposed as a necessary factor for the formation and preservation of the sequence described in this atypical location.