The Geological and Geodynamic Evolution of the Northumberland Trough Region, Northern England

The geological and geodynamic evolution of the Northumberland Trough region, Northern England. Linda Austin, Stuart Egan and Stuart Clarke

Earth Sciences and Geography, School of Physical and Geographical Sciences, Keele University, Staffordshire, ST5 5BG, United Kingdom (Email: [email protected])

m d s

h m

e o e c

a a

i i

g r r o

Cross-section path for g t

s Remarks including Major Regional Events Legend M

t Tectonics Sedimentation

e e

E p

A a

A y

50Km r

S P S E

Figures 3, 5 and 6 S 1. INTRODUCTION E 65.5 ±0.3 West East Maastrichtian Extension with 70.6 ±0.6 Campanian transtension 83.5 ±0.7 The Northumberland Trough region is an area of northern England including the Northumberland Trough, its westerly continuation, Santonian Upper 85.8 ±0.7 Coniacian

s 89.3 ±1.0

u Turonian 93.5 ±0.8 the Solway Trough, the Alston Block, a structural high situated to the south of the Northumberland Trough, the Vale of Eden Basin to o Cenomanian Cross-section paths e 99.6 ±0.9

c Albian Extension a

t 112.0 ±1.0 Aptian Maryport-Stublick-Ninety Fathom Fault e the west of the Alston Block and the Stainmore Basin to the south of the Alston Block (Figure 1). r 125.0 ±1.0

C Barremian Hexham Lower 130.0 ±1.5 Opening of the Atlantic Ocean in the sin Hauterivian west and subsidence of the North Sea a 136.4 ±2.0 B Carlisle Basin to the east (Ziegler, 1990). ay Valanginian This work investigates the structural, stratigraphical and geodynamic processes that have controlled the development of the lw 140.2 ±3.0 o V Berriasian S a Alston Block 145.5 ±4.0 Compression l Alston c e i Tithonian P Durham o e o 150.8 ±4.0 n f n z Upper Kimmeridgian E in e 155.7 ±4.0 Northumberland Trough region. Existing and new two-dimensional and three-dimensional tectonic modelling techniques are being d o

e F Oxfordian

a s n u 161.2 ±4.0 l ult Penrith B t wle Fa e Callovian tterkno a -Bu c 164.7 ±4.0 ale i d M s -Lune Bathonian i se s applied to the Northumberland Trough region. Results from basin analysis and field-based work are providing input parameters to Lake District Block n osehou gh 167.7 ±3.5 Cl ou s Middle e Tr Bajocian Uplift of the North Sea Dome (Ziegler, or a tainm r 171.6 ±3.0 1990). Erosion

S u Aalenian

J 175.6 ±2.0 resolve how the interactions between geological and geodynamic processes have contributed to the complex subsidence and Toarcian 183.0 ±1.5 Pliensbachian Lower 189.6 ±1.5 Duration Sinemurian 196.5 ±1.0 of uplift history of the Carboniferous block and basin structure of the region. Hettangian Erosion of Permo-Triassic and younger Event Figure 1: An overview of the Carboniferous structure of the 199.6 ±0.6 Rhaetian sediments has removed a large amount 203.6 ±1.5 of sedimentary cover. The thickness Northumberland Trough region, showing the position of the cross- Upper Norian and extent of rocks that have been

c 216.5 ±2.0 i Carnian eroded is unknown. There are sections drawn as part of the research. s 228.0 ±2.0

s Ladinian considerably more Triassic and a i Middle 237.0 ±2.0 Jurassic sediments preserved in the r Anisian north-west of England than in the north- T 245.0 ±1.5 Olenkian east of England (Clarke, 2008). SE N Lower 249.7 ±0.7 NW S Induan In late Permian to early Triassic times, 50Km 251.0 ±0.4 Changhsingian there was a transition from a Lopingian 253.8 ±0.7 Wuchiapingian predominantly marine to a continental 50Km 260.4 ±0.7 environment across northern England 0 Capitanian (Chadwick et al., 1995). n 265.8 ±0.7

a Guadalupian Wordian

i 268.0 ±0.7 To the west of the Pennines, east-west

m Roadian r 270.6 ±0.7 orientated extension reactivated large

e Kungurian 1 fault structures in the underlying

P 275.6 ±0.7 Artinskian Carboniferous strata (Clarke, 2008). Cisuralian 284.4 ±0.7 Sakmarian Uplift of the Carboniferous basins 294.6 ±0.8 resulted in considerable erosion of the Asselian 299.0 ±0.8 Carboniferous strata during the 2 Alston Block n Gzhelian a

i Permian Period (Chadwick et al., n s Upper 303.9 ±0.9 a

u Kasimovian 1995). v l

o y 306.5 ±1.0

r s Variscan Orogeny- Collision between n Middle Moscovian

e n

i 311.7 ±1.1 e Pennine Coal Measures Avalonia to the North and Gondwana to P n Lower Bashkirian 3 Group the South. Towards the end of the

o 318.1 ±1.3

c a

b i Upper Serpukhovian i Variscan Orogeny the Whin Sill Suite

r p

p 326.4 ±1.6 i Yoredale Group

a o s was intruded (Johnson & Dunham,

s Middle Visean

i z C m

s 345.3 ±2.1 s

i Border Group 2001). o K Tournasian M Lower

e 359.2 ±2.5 l h 4 Famennian The extensional phase of the

a 374.5 ±2.6 Northumberland Trough's evolution is p Upper

Frasnian P

e n 385.3 ±2.6 characterised by a close association a

D i Giventian b e t w e e n s e d i m e n t a t i o n a n d

n Middle 391.8 ±2.7 contemporaneous faulting (Chadwick 5 o Eifelian

v 397.5 ±2.7 et al., 1995). e Emsian 407.0 ±2.8 Basement Elevation D Lower Pragian 411.2 ±2.8 Northumberland Trough Lockovian Caledonian Orogeny- Collision 6 416.0 ±2.8 between Laurentia to the North and N Pridoli Stainmore Trough E 418.7 ±2.7 Avalonia to the South resulting in the Ludfordian closure of the Iapetus Ocean (Beamish Ludlow 421.3 ±2.6 Gorstian & Smythe, 1986).

n 422.9 ±2.5 a

i Homerian

7 The stepping nature of the faults on the southern edge of the basin is visible in the centre of the cross-section r

Wenlock 426.2 ±2.4 u

l Sheinwoodian i 428.2 ±2.3

Figure 4: A selection of cross-sections digitised in AutoCAD shown in S Telychian 436.0 ±1.9 Llandovery Aeronian their 3D co-ordinate system. 439.0 ±1.8 8 Rhuddanian North Pennine Batholith 443.7 ±1.5 KEY New Nomenclature Previous Nomenclature Figure 2: Tectonic and stratigraphic evolution of the Northumberland Stainmore Formation Stainmore Group Trough region. Yoredale Group Alston Formation Liddesdale/Alston Group Tyne Limestone Formation Upper Border Group Fell Sandstone Formation Middle Border Group Basin Model Development of Basin Over Time Border Group Lyne Formation Lower Border Group Upper Lower Border Group Lower Distance (Km) 5 20 50 65 85 3. MODELLING Weardale Granite North Pennine Batholith 10 15 25 30 35 40 45 55 60 70 75 80 90 95 0

Figure 3: A north-south structural and stratigraphical cross-section across the Northumberland Trough, the Alston Block and the Stainmore Trough. The present- 0.5 Numerical modelling that includes structural, thermal, isostatic and surface 1

day Northumberland Trough is bounded at its southern margin by the Maryport-Stublick-Ninety Fathom en-echelon fault system. It was this fault system that Syn-Rift Subsidence controlled the structural evolution of the basin during Carboniferous and post-Carboniferous times although early development of the basin was controlled by 1.5 processes (Egan and Meredith, 2007) has been applied to the data collated within

KEY

) 2 extensional faults in a more distal position than the Stublick fault (Chadwick & Holliday, 1991). This can be observed on this structural cross-section of the area Basin after: 0My m 5My

K 10My

(

Alston Block 50My the study area. The algorithms allow the amount of subsidence at any individual 2.5 where there are several faults over which the total displacement is distributed. h

t 100My

p 300My

e D 3 point in a basin to be calculated, based on a number of lithospheric (e.g. 3.5 Post-Rift Subsidence 2. STRATIGRAPHY AND STRUCTURE 4 temperature) and deformational (e.g. magnitude of extension) parameters, which

4.5 Northumberland Trough Stainmore Trough are either assumed or determined from available data. A two-dimensional model An analysis of the tectonic and stratigraphical evolution of the Northumberland Trough region 5 can be produced to show the geometry and depth of the basin and its is presented in Figure 2. In addition, fieldwork data and subsurface geophysical data have Figure 5: This model shows the development of the structure of the basin and block system over time. With the syn-rift subsidence development over time (Fig 5 & 6).In the model, the Alston Block shows greater been collated within a GIS environment and used to produce regional cross-sections showing occurring instantly and the post-rift thermal subsidence occurring at present day structure and stratigraphy across the region. Figure 3 shows an example of one of an exponential rate. subsidence than is observed from sub-surface data. This may be explained by the the north-south orientated sections across the eastern part of the study area. Two east-west presence of a low density granite intrusion, the North Pennines Batholith, beneath Basin Model orientated cross-sections have been drawn to tie the data together, ready for a three- Present Day Basin Structure and Stratigraphy the Alston Block. Algorithms to model the effects of an igneous intrusion upon the Distance (Km) 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 dimensional interpretation of the area (Figure 4). 0 geodynamic response to continental extension are currently under development.

1 Post-Rift Deposition

2 4. CONCLUSIONS 0°C 4 km 5 km Figure 7: The major processes Figure 8: Model profiles ) 750C

-3 m k Crust 2800 kg.m

K 0

( 3 277 C across the study area 3 Alston Block associated with extending the h Moho t A two-dimensional kinematic modelling approach has been used to provide 4800C p assuming fault deformation e -3 lithosphere by, both faulting and Mantle 3300 kg.m Crust D Syn-Rift Deposition

7470C m

k o f u p p e r c r u s t a n d 4 0

9 insights into the structural, thermal and isostatic evolution of the Northumberland KEY pure shear mechanisms, can be 10130C Isotherm Pure Shear extension of lower crust Time = 0Ma (Width = 125 km) Te = 5km Permo-Triassic Stainmore Group 13000C combined together into a 1330°C and mantle lithosphere by 5 Liddesdale/Alston Group Upper Border Group Trough region. Cross-sections have been analysed within a three-dimensional co- Asthenosphere Middle Border Group quantative model. pure shear. Northumberland Trough Lower Border Group Upper Lower Border Group Lower post-rift 6 Stainmore Trough Relative uplift At Time = 0Ma there is Post-rift ordinate frame to show regional variations in basin depth and burial history, as well e e e e Beneath the fault detachment of footwall syn-rift z extension via movement Figure 6: This model represents the present day basin structure and Z depth, the lower crust and mantle d Crust along the faults at the as the position and magnitude of movement along major faults. Further Crust Syn-rift stratigraphy assuming an original crustal thickness (Co) of 32Km. The are deformed mainly by pure Moho surface and extension via Mantle total amount of subsidence in the basin is comparable to the amount Isotherm Time = 350 Ma development of the modelling algorithms is now taking place in order to generate a shear. pure shear beneath the Te = 10km of observed subsidence in the basin (Figure 3), however the Alston fault detachment depth. Block is substantially deeper than observed. realistic three-dimensional model, incorporating the effects of the granite.

References and Acknowledgements Beamish, D. and Smythe, D.K., 1986, Geophysical images of the deep crust: the Iapetus Suture. Journal of the Geological Society of London, Vol. 143, 489-497. Chadwick, R.A. and Holliday, D.W., 1991, Deep crustal structure and Carboniferous basin development within the Iapetus Convergence Zone, northern England, Journal of the Geological Society of London, Vol. 148, 41-53. Chadwick, R.A., Holliday, D.W., Holloway, S. & Hulbert, A.G., 1995, The structure and evolution of the Northumberland-Solway Basin and adjacent areas, Subsurface Memoir, British Geological Survey, London HMSO. Clarke, S.M., 2008 (in press), The Permian, Triassic and Jurassic. In Stone, P., Ed, British Regional Geology: Northern England (5th Edition), British Geological Survey, Keyworth, Nottingham. Egan, S.S. And Meredith, D.J., 2007, A kinematic modelling approach to lithosphere deformation and basin formation: application to the Black Sea. In Karner, G.D., Manatschal, G. And Pinheiro, L.M. (Eds)Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup. Geological Society, London, Special Publications, 282, 73-198. Johnson, G.A.L. and Dunham, K.C., 2001, Emplacement of the Great Whin Dolerite Complex and the Little Whin Sill in relation to the structure of northern England, Proceedings of the Yorkshire Geological Society, 53, 177-186. Kimbell, G.S., Carruthus, R.M., Walker, A.S.D. AndWilliamson, J.P., 2006, Regional Geophysics of Southern Scotland and Northern England, Version 1.0 on CD-Rom (Keyworth, Nottingham: British Geological Survey). Research Institute for the Environment, Physical Sciences & Applied Mathematics This research has been conducted as part of a PhD study - part funded by the British Geological Survey (BGS).