Virtual Field Trip from virtual-geology.info

Locality: South Elmsall, South Yorkshire

It is important that you access this field trip on a laptop or desktop PC. Click on any image to enlarge it.

Where are we? This disused quarry is located along a minor road, 1 km to the northeast of the village of South Elmsall, 10 km to the southeast of Wakefield. Grid Reference: SE 484 116. At this location, we will study and interpret part of the Wetherby Member of the Cadeby Formation Formation, of Late Permian age. Study the area in Google Maps and Street View

The locality is the corner of a former large quarry, preserved as an SSSI after the main site was infilled with landfill.
Geological and locality map
Stratigraphy (Fig. 7, near the bottom of the linked page)
There's a lot to see and do at this location, and we usually spend about 2 hours making observations.

Geological background: this location provides exposure through part of the Permian (290-248 million years ago) Magnesian Limestone. These limestones were deposited in a relatively shallow landlocked sea extending from north east England to Poland, known as the Zechstein Sea - palaeogeography (see slides 3, 4 and 8). The estimated average sea temperature during the period was approximately 23°C. Within the Magnesian Limestone the remains of fossil reefs, known as patch-reefs, which grew on the edge of the Zechstein Sea can be found. This locality provides exposure through one of the most complete and best-exposed patch-reefs in the British Permian succession and comprises a massive core of limestone formed by bryozoans mantled by domes of laminated limestones. The shallow-water limestones surrounding the reef contain abundant fossil bivalves and gastropods and provide evidence of the marine life that inhabited the area around the reefs.

Task: your main task is to construct an interpreted panel for the sections seen at this location, by annotating the panorama of the quarry face.

Download appropriate panoramas of the whole outcrop from A to C. Photos 4,5 and 6 may work best, but it's your choice
Insert the photos into a PowerPoint file.
Draw on contacts, identify sedimentary features, and write brief interpretations.
Use symbols or abbreviations, and make sure you include them all in a key.
Answer the questions with individual photos and use this information in your panel.
You will need to acquire information on lithologies, thicknesses and geometry of sedimentary units, sedimentary structures and palaeocurrent directions, fossils and trace fossils, lateral and vertical changes etc.
From these observations, you should be able to attempt interpretations of the the processes and environments involved in the formation of the section.

1. General view, looking east, of the main quarry face at South Elmsall, with a University of Derby MSc group.

2. Sketch map of the quarry at South Elmsall, based on a Google Maps image.
The photographs below are located with reference to points A, B and C on the map.
Scale bar is 20m long.

Field evidence

Describe the outcrop photographs below, and use them to provide evidence on which to base your interpretations. Pay particular attention to field relationships - contacts between units, how units change as you trace them laterally, etc.

Important note: although this is a carbonate locality, most parts of the section react only weakly with dilute HCl. A stronger reaction may occur if the rock is powdered first.

3. Panorama of the whole exposure. Note that face A-B is roughly at right angles to face B-C (see map above).

4. Face AB in more detail.

5. The face either side of point B.

6. The east face of the quarry, BC

7. Closer view of the face at point A.	8. Close-up of Photo 7.	9. Close-up of Photo 8. Describe the sedimentary structures.	10. Close-up of Photo 9. Describe and identify the sedimentary structures. Can you get any directional information from them?
11. Near the centre of face BC Note the presence of bedded limestones in the lower part of the section.	12. Close-up of the bedded limestones near the base of Photo 11.	13. Close-up of Photo 12. Reaction with dilute HCl is weak.	14. Close-up of Photo 13. What are the round grains likely to be? They show no internal structure, due to diagenesis. What can you see between the grains?
15. Face to the right of point B. You should be able to identify and describe 3 different units here.	16. Close-up of face to the right of point B. Note the massive unit between two bedded units. This massive lithology is difficult to identify, even in the field, because of extensive diagenesis which has destroyed much of the primary structure. It contains stick bryozoans, and has been interpreted as a bryozoan patch reef. A published description records the following: lithology: buff, massive bryozoan framestone/bafflestone sparse framework of arborescent Acanthocladia colonies dolomite microspar and micrite matrix a few casts of bivalves, mostly Bakevellia	. 17. The section immediately above the graffiti face seen in Photo 16. Note the nature of the contact just above the geologists' heads. Above is the massive bryozoan reef unit, with many large vugs.	18. Central part of face BC. Describe the bedding/lamination seen in the top part of the face, above the massive unit. This facies is seen again in the following photos.
19. Detail of the face near the right end of Photo 18. Note that the massive, vuggy bryozoan reef unit (just above the geologist's arm) is much thinner here. Describe all three units seen here.	20. Right part of face BC. Scale is standing near point C. Describe the sequence here. Is it different to the sequence seen further north (left) on this face?	21. Closer view of face in Photo 20. Concentrate on the nature of the bedding/lamination in the upper part of the face. The grain size of this unit is predominantly micrite. What might it represent? What does it tell us about conditions of deposition?

Interpreting the field evidence

On your panel, suggest depositional processes, conditions and environments for each depositional unit you have identified.
How many sedimentary facies can you define here? Do any of them repeat?
Write a short (250 word maximum) interpretative account of changes in processes, conditions and environments from the base to the top of the section, taking into account lateral variations.
Comment on the reservoir potential of each of the sedimentary units.

This page is maintained by Roger Suthren. Last updated 18 November, 2020 8:59 AM . All images © Roger Suthren unless otherwise stated. Images may be re-used for non-commercial purposes.