The first BSRG postgraduate field trip of 2018 visited Permian Zechstein outcrops of Northeast England. The trip was led by Professor Maurice Tucker and Michael Mawson of the University of Bristol and Durham University, organised by Arne Fuhrmann and Dan Tek from the universities of Manchester and Leeds and sponsored by the International Association of Sedimentologists (IAS). A diverse group of researchers from universities in Europe and North America made discussions stimulating and wide-ranging.
After an evening of introductions, we started the action packed, two-day trip on Saturday morning at Claxheugh Rock, where the basal contact of the Zechstein Raisby formation crops out. The stunning exposure shows a slide palne separating aeolian Yellow Sands from overlaying Marl Slate. Working our way up through the stratigraphy, we visited Trow Point where the uppermost Raisby Fm. is overlain by Trow Point Bed. It consists of a 10 cm thick microbial unit equivalent to 100 m of reef carbonate just 5 km to the west, and a thin layer of residue from the dissolution of the Hartlepool Anhydrite. Above the Trow Point Bed, the concretionary Roker Formation is present as a collapse breccia.
After a nice lunch at Marsden Bay, we continued to look at the Rocker Fm. which exposes a number of primary and resedimented carbonate facies, including cross bedded, shelf-margin bioclastic oolites, and calc turbidites. The Roker Fm. also shows some spectacular secondary carbonate features such as the bizarre ‘cannonball limestones’ and oomoldic porosity. Day one ended with a look at the dolomitised reef facies of the Ford Fm. with some impressive fossil assemblages.
In the evening, after a hearty evening meal, the group received a private tour of Durham Castle courtesy of Maurice, the former Master of Castle.
Day two started at Blackhall Rocks, with a jump into the weird and wonderful world of microbial carbonates. Microbial dolomites and stromatolites exposed in exceptional sections along the coast of County Durham, the most notable of which was the distinctive ‘Crinkly Bed’. Walking through the caves and past the cliffs, reefal and slope carbonates, some of them brecciated, were visible alongside these enigmatic microbialites. We finished the two fantastic days at Seaham Harbour, looking at the youngest outcropping Zechstein strata in Durham, the contact between to Rocker Fm. and the Fordon evaporates.
We would like to thank the trip leaders, Maurice Tucker and Michael Mawson for taking us to these amazing outcrops and everyone attending the trip for their valuable contribution!
Dan Tek, Postgraduate Representative