Characterisation of Quaternary Deposits in West Cumbria Using the Concept of Domains: a Case Study

Characterisation of Quaternary deposits in West Cumbria using the concept of domains: a case study

Characterisation of Quaternary deposits in West Cumbria using the concept of domains: • Quaternary Characterization Programme A case study • Glaciation of West Cumbria • Development of hydrogeological domains • Recent modelling requirements Jon Merritt • Multi-till sequences: The ice-stream legacy in northern England • Conclusions

Conceptual The Calder hydrogeological Catchment model for West Cumbria

Former PRZ Sherwood Sandstone Group

Drigg LLWR after McMillan et al., 2000. QJEGH, 33, 301-323

Local 1:50 k Sellafield Bedrock and hydro- Superficials Superficial share geological common Geology profiles water table Superficials contribute to transmissivity of regional Recharge through aquifer Superficials at both sites

Drigg Perched water tables Mapped Superficials in 1920s impede recharge to Drigg Deemed underlying ‘fit for after McMillan et aquifer purpose’ al., 2000. QJEGH, 33, 301-323 NEXTMap BritainTM elevation data from Intermap Technologies.

1 NIREX BGS Quaternary litho- Characterization stratigraphy Programme at Drigg Thin pebbly 1993-97 clays

Sand- Great contrast filled in types of till channels and 25 boreholes provenance Dense 57 trial pits gravelly 27 sections tills targetted mapping geophysics and much more

Nirex Science Report S/97/002 From BGS Technical Report WA/99/80

Contrasting tills in West Cumbria

Coastal sequences

Scotland

Wales England

Inland tills

Last Glacial After major Maximum glacial 28-22 ka BP reorganisation c.18 ka BP Irish Sea Ice Stream Followed by impinges Glaciers glacial re-advances into West flowing Cumbria from the Cumbrian Mountains From British From British Regional Geology Regional of Northern Geology of England, 5th Northern Edition, BGS, England, 5th 2010 Edition, BGS, 2010

2 Ice Streams Ice slowly Streams Ice moving stream ice heavily crevassed shear zone

West Antarctic Ice Stream D

Velocities: c. 0.4 – 4.0 km per year

West Litho- Shear zone at landward margin of Cumbria stratigraphy ice stream? during the of West Gosforth Cumbria Oscillation Wasdale

Site of former ice- marginal lake Irish Sea Ice Sream Drigg

After Merritt and Auton, 2000, Nirex Science Report Proceedings of S/97/00 the Yorkshire Geol Soc, 53, 129-154

Lithostratigraphical Framework Quaternary Domains

Nirex Science Report S/97/00 After McMillan, A A, Hamblin, R J O and Merritt, J W. 2010. A lithostratigraphical framework for onshore Quaternary and Neogene(Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03.

3 Detailed Transect Profiles in across Nether Nether Wasdale Wasdale

Glaciolacustrine domain

After Merritt and Auton, Nirex 2000, Science Proceedings of Report the Yorkshire Geol Soc, 53, S/97/00 129-154

Glacio- Hydrogeological lacustrine Domains Domain

From McMillan et al., 2000. QJEGH, 33, 301-323

Examples of Till-Sand-Till hydrogeological Domain domains

From McMillan et al., 2000. QJEGH, Downward fissure-flow 33, 301-323 through till layers

4 Regional The Ice groundwater Stream flow model for Legacy the Calder Pebbly catchment Glacially Over- clay based on ridden Domain domains Till-Sand-Till Domain

From McMillan et al., 2000. QJEGH, 33, 301-323 Subglacial attenuation and microfaulting Nirex Science Report, S/97/012

The Ice Stream The Ice Legacy Stream Legacy

Glacitectonic Trust Domain

Glacially Over-ridden Tills are thin, but laterally extensive Domain After Merritt and Auton, 2000, Lenses of sand and gravel (channel-fills) Proceedings of the Yorkshire Geol Soc, 53, 129-154 Partition of groundwater flow

After major Recent work glacial reorganisation c.18 ka BP

Maiden’s Hall North Sea Ice Stream Ice Stream legacy impinges into NE England

Tyne and From British Wear Regional Geology Complex Detailed stratigraphical of Northern th correlation and 3D modelling England, 5 Edition, BGS, Pelaw 2010 Clay enigma

5 Ice 20 m Multi-till Stream sequences in Legacy NE England

Maiden’s Hall opencast site, Sequence Morpeth within a concealed channel -10 m From British Regional From British Geology of Regional Northern Geology of England, 5th Northern Edition, BGS, England, 5th 2010 Edition, BGS, 2010

Ice Stream Ice Stream Legacy Legacy

Maiden’s Hall opencast site, near Morpeth, Gradational contacts in 1999

Sharp bases

Photo Jon Thin pebbly tills Merritt

© NERC All rights reserved After British Regional Geology of Northern England, 5th Edition, BGS, 2010 © NERC All rights reserved After British Regional Geology of Northern England, 5th Edition, BGS, 2010

Ice Stream Ice Legacy Stream Legacy Very dense, over- consolidated

Laterally extensive Subglacial Sharp, aquitards shearing planar contacts Potential slippage planes

Lensoidal Slightly over- aquicludes consolidated

After British Regional Geology of Northern England, 5th Edition, BGS, 2010 After British Regional Geology of Northern England, 5th Edition, BGS, 2010 © NERC All rights reserved © NERC All rights reserved

6 Ice Stream BGS GSi3D Legacy modelling in County Durham

Sharp planar top

Subglacial channel fill

Water ingress hazard

Comparison of borehole core and logs following BS 5930, Drigg. Towards a subdivision Fewer, more of tills informative logs in site investigations please!

When is

gravel

really a till? Moderate reddish brown (10R 4/6) silty fine to medium grained SAND and fine to coarse subrounded to angular GRAVEL/COBBLES with some coarse to very coarse sand. After McMillan, Hamblin, and Merritt, 2010. A lithostratigraphical A best guess is Fine to coarse rounded to angular GRAVEL with some pale framework for onshore reddish brown (10R 5/4) to moderate reddish brown (10R 4/6) better than fine to medium sand matrix (washed out) and occasional …superficial deposits of coarse sand. 35.90-35.94m fine to medium sand. Great Britain... nothing BGS Research Report RR/10/03. FromHow ‘ Guidelines,an extremely protocols compact, and stonyStandards till can to Quaternary be interpr etedmapping to be in and the aquiclude United Kingdom’, BGS, in press.

Conclusions

• Domains approach useful for regional hydrogeological modelling of Superficials

• Detailed 3D lithostratigraphical knowledge still required to underpin modern high-resolution hydrogeological models

• Former ice streams have left a distinct legacy of particular importance to engineering geologists and hydrogeologists

Employ Quaternary • More informative site investigation logs required geologists in site investigations • Desirable to consult Quaternary geologists at all stages of site BGS image P666392 investigations