Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian) at Whitman’s Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics; pp. 287–292

A Munnecke,D C Ray,E Jarochowska,G Worton,J-F Päßler

doi:10.3176/earth.2014.32

Abstract

Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian) at Whitman’s Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics; pp. 287–292

Highlights

The Mulde Event (Homerian, middle Silurian) has been introduced as an extinction event affecting conodonts (Jeppsson 1993) and corresponds to the ‘Big Crisis’ in graptolites, known as the lundgreni event (Jaeger 1991; for a summary see Cramer et al 2012)
The onset of the Mulde positive carbon isotope excursion (CIE) has been identified in the northern Midland Platform (Dudley, West Midlands) at the boundary between the Coalbrookdale Formation (CF) and Lower Quarried Limestone (LQLM) (Corfield et al 1992; Marshall et al 2012)
The transgressive deposits are characterized by an abrupt appearance of microbially-mediated carbonates, either as oolites – e.g. the Bara Oolite Member of the Halla Formation in Gotland (Calner & Säll 1999) or the Limberlost oolite of the Cincinnati Arch (Brett et al 2012) – or as oncoids, e.g. in Estonia (Kõrts 1991), Podolia (Jarochowska et al 2014a) and Gotland (Calner 2005)

Summary

Introduction

The Mulde Event (Homerian, middle Silurian) has been introduced as an extinction event affecting conodonts (Jeppsson 1993) and corresponds to the ‘Big Crisis’ in graptolites, known as the lundgreni event (Jaeger 1991; for a summary see Cramer et al 2012). A microbial origin has been proposed for matrix-supported, low-diversity buildups reported from different palaeocontinents during the onset of the Mulde positive carbon isotope excursion.

Results

Conclusion