Palaeokarst features at Sands Top Quarry, North Newbald, East Yorkshire, UK.
[or one of our trowels is missing]
A preliminary report -containing rough drawings and raw data.
updated 16/10/3
Fieldwork carried out by members and friends of the Hull Geological Society in 2002 and 2003 - Allen Parker, Anne Horne, Barrie Heaton, Chris Leach, Colin Clark, Derek Gobbett, Felix Whitham, Mike Horne, Nigel Whittington, Paul Richards, Stuart Jones, and Terry Rockett.
Mapping and levelling by Allen Parker & Barrie Heaton.
Digging, measuring and logging by Barrie Heaton, Chris Leach, Colin Clark, Mike Horne, Nigel Whittington and Stuart Jones.
Sample processing and sedimentology by Colin Clark.
Man with bottle of acid (burning a hole in his pocket) - Colin Clark.
Collation and text by Mike Horne.
The quarry is in the Cave Oolite, Middle Jurassic (Bajocian Stage).
The limestone is overlain by sands and silts, but there are features cut into the upper surface of the limestone. Some of these are filled with sandy-clay deposits which has weathered our of others. Where they are empty these features have smooth rounded walls - they are not just cracks that have been caused by cambering or some similar process. They are clearly caused by solution of the limestone.The consensus of those who have seen them is that they are palaeokarst features. But what is their age - are they a Jurassic karst with Jurassic infill, a Quaternary karst with Quaternary infill or solution features that have been infilled by slumped overlying Jurassic beds?
Measurements of the features are based on an West to East line along the quarry floor - and are given in approximate distance in metres along this line.
Detailed log of the Cave Oolite and references
Jurassic Stratigraphy of the Newbald area.
picture of weathered sands and silts above the Oolite
Scale diagram of the features.
Detailed drawing of the central features ca 55-65m along line
Photo of some of these central features ca-57-59m [A4 file for scale]
detailed measurements of feature at 59.5m (site 2)
detailed measurements of section dug at 74 m (site 1)
scale diagram of 'sink hole/channel' feature at 74-76 m
picture of the top of the oolite at ca 90m
detailed measurements of feature on east face of the quarry (possible ice wedge cast)
picture of feature on east face of the quarry
Log of section 4 (measured 12/10/3) above Cave Oolite at western end of quarry face.
> 50 cm pale greay micaceous silts (sample108).
erosion surface
9cm buff silt with some 'iron pan' and sand lenses.
erosion surface
7-13cm buff laminated sand
erosion surface
36cm layered buff and brown sands with grey and red patches
20cm buff sand (sample 10)
7cm buff-brown layered sand
38cm layered buff sand with patches of 'iron pan' and lenses of grey sand
20cm grey silty sand (sample15)
13cm layered 'iron pan' and buff sand
15cm buff sand (sample 9)
4cm 'iron pan'
5cm brown clay
top (rounded) surface of Cave Oolite with karst features cut into it infilled with brown silty clay (sample 102).
Samples collected:-
[note - position quoted as distance along our east-west line]
9 below blue grey silts from 'section 4'
10 above blue grey silts from 'section 4'
11 - EV2 - brown sands and silts from feature in Everthorpe Quarry, South Cave.
13 from bottom of feature 'site 2' (59.5m)
14 from band of angular rock fragments 'site 2' (59.5m)
15 blue-grey silts from 'section 4'
16 - wind blown sand - Sewerby buried cliff.
17 - SC - Kellaways Sand from Station Quarry, South Cave.
18 - EV1 - blue-grey silts from feature in Everthorpe Quarry, South Cave.
21 under overhang at right side of sink hole 74-78m
22 from left side of sink hole 74-78m (hopefully including limestone debris)
24 grey silts from right side of sink hole 74-78m
25 from underneath 'iron pan' at far right of sink hole 74-78m
26 from pebbly deposit in V shaped feature 56.5 m along line.
31 fine sand with iron staining base of section 1 (74m)
32 'iron pan' above sample 31 at section 1 (74m)
33 silty sand with some clay inclusions above sample 32 at section 1 (74m)
34 grey silt above sample 33 at section 1 (74m)
40 sample of infill of 'ice wedge' feature on upper shelf or eastern face.
101 from bottom of feature @ 26.5 metres
102 brown silt/clay from karst infill in section 4
103 from bottom of feature @ 59 metres
104 from bottom of feature @ 59.5 metres
105 from bottom of feature @51.5 metres
106 from bottom of right hand doline in eastern face
107 from bottom of left hand doline in eastern face
108 grey mcaceous silts (top of section 4)
A upper clay band in Cave Oolite
B lower clay band in Cave Oolite
90 "clay with flints" above gravels and below diamicton at Welton-le-Wold, Lincolnshire.
91 Kellaways Sand from Burythorpe sand pit NGR 785655 (larger sample)
92 sand from James Crag SSSI above Whitwell Limestone NGR 736672
93 sample of sand (ask Nigel for details)
Results
Acid Tests -
No reaction - samples 9, 10, 15, SC, EV1, EV2.
Crystaline material in sample 14 does not react with acid - could be gypsum.
Rection - 13
Sedimentology/Micropalaeontology -
[initial observations of some samples]
No microfossils found.
sample 15 - blue grey silts - > 90% very clean clear quartz, mostly angular, some larger well rounded grains; some yellow quartz and muscovite.
sample 11 - Everthorpe sands - better sorted than sample 15 and more rounded. 99% quartz, plus a little muxcovite.
sample 10 - well sorted, 25% rounded, hardly any muscovite, 50% clear quartz, 50% dull yellow coated quartz.
sample - Sewerby blown sand - coarser, more rounded and frosted.
sample 9 - medium sorted (similar to no 10), 50% clar quartz + 50% dull yellow-coated quartz; very little mica, some grey quartz and black grains.
sample 13 - ooliths and sinter. The sinter reacted with acid -- probably it is the sparry cement of the Oolite left after solution of the ooliths.
sample 14 - crystalline but not carbonate - might be gypsum.
Discussion -
This study has found features cut into the top of the Cave Oolite Member. There is no ecidence of a hardground or rockground on the upper sufarce of the Oolite. There is evidence of acidic solution of the oolite in the features - a calcite sinter in the basal deposits in one feature caused by the solution of the ooliths but not the sparry cement. The overlying silty sands and the Kellaways Sandshave also contain no carbonte in the sediment. Fossils in the Kellaways Sands and Rock are have been subjected to acid solution - for example badly deteriorated belemnites, and complete solution of belemnites leaving only the phragmacone.
Other authors have recorded the erosion or solution of the top of the Cave Oolite.
Brasier and Brasier (1978) envisaged the erosion of the Cave Oolite in Bathonian times and the deposition of carbon and sulfur-rich sandy clays in acidi reducing conditions of marshes, swamps and stagnant pools. "Emeregence is further indicated by the deep channel cut into the limestone [at Eastfield Quarry, South Cave] and later filled passively with muddy White Sands"(pp 3, 9 &17). They also record the decalcification of the fossils in the Kellways Sands.
Gaunt et al (1992) state " The best evidence of the Thorncroft Sands occupying solution hollows in the underlying Lincolnshire Limestone is at Eastfield Quarry, where the base of the sands cuts down through 1.8 m of Cave Oolite to produce a channel-like profile 8 m wide. ... they are not part of a channel fill but, having originally been deposited on a level surface, have subsided into a hollow at he top of the Cave Oolite, presumably due to solution of the limestone by acidic groundwater." (p52).
Acknowledgements -
We are grateful to Darren Griffiths and Stoneledge for permission to visit the quarry.
Comments
"Locality much like karstified top of Lincolnshire Limestone beneath Stamford Member ((Rutland Formation) in South Lincs." Mike Sumbler 18th October 2003.
Mike Horne,
Hull, East Yorkshire, UK.
