The lost Lower Old Red Sandstone of England and Wales: a record of post-Iapetan flexure or Early Devonian transtension?

2003 ◽  
Vol 140 (6) ◽  
pp. 627-647 ◽  
Author(s):  
N. J. SOPER ◽  
N. H. WOODCOCK
Keyword(s):  
High Heat ◽  
Sediment Provenance ◽  
Lake District ◽  
East Anglia ◽  
Early Devonian ◽  
England And Wales ◽  
Red Sandstone ◽  
Scottish Highlands ◽  
North Wales ◽  
Slate Belts

Illite crystallinity data from the Silurian slate belts of England and Wales indicate anchizone to low epizone metamorphism during the Acadian deformation in late Early Devonian time. This metamorphic grade implies a substantial overburden, now eroded, of Lower Devonian non-marine sediments of the Old Red Sandstone (ORS) magnafacies. A minimum 3.5 km pre-tectonic thickness of ‘lost’ ORS is estimated in the southern Lake District and comparable thicknesses in North Wales and East Anglia. Tectonically driven subsidence of the underlying Avalonian crust is required to accommodate such thicknesses of non-marine sediment. One proposed mechanism is flexure of the Avalonian footwall during convergence that continued from Iapetus closure in the Silurian until Acadian cleavage formation in the Emsian. The evidence for this model in the critical area of northwest England is reviewed and found to be unconvincing. An alternative model is developed following a recent suggestion that the Early Devonian was a period not of continued convergence but of orogen-wide sinistral transtension. Transtensional accommodation of the lost ORS is evidenced by Early Devonian extensional faults, by synchronous lamprophyric magmatism, and by compatibility with previously diagnosed sediment provenance patterns. A summary of Siluro-Devonian tectonostratigraphy for Britain south of the Highland Border emphasizes that, unlike the Scottish Highlands, this area was not affected by the Scandian Orogeny, but was by the Acadian. An important period of sinistral transtension in the Early Devonian (c.420–400 Ma) was common to both regions. This was a time of high heat flow, lamprophyric and more evolved magmatism, and major southward sediment transport, involving mainly recycled metamorphic detritus from the Highlands and from contemporaneous volcanicity. Old Red Sandstone, deposited in coalescing transtensional basins over much of Britain from the Midland Valley to the Welsh Borders, was largely removed and recycled southward during Acadian inversion.

Geological setting of the useful minerals in Britain

1974 ◽  
Vol 339 (1618) ◽  
pp. 273-288 ◽  
Keyword(s):  
Ferrous Metal ◽  
Lake District ◽  
East Anglia ◽  
South Wales ◽  
North Wales ◽  
Lead And Zinc ◽  
Lead Zinc ◽  
Lower Palaeozoic ◽  
Sand And Gravel ◽  
Orogenic Belts

Great Britain was endowed with mineral wealth out of proportion to its small size. This is partly the result of its situation at the crossing-place of two of the three major European orogenic belts, the Caledonian and Hercynian, but perhaps more the result of the intense circulation of hot mineralizing fluids in systems of tension faults which were active at inter­vals from early Permian to Tertiary or possibly even to Neogene times. In the peninsula of Cornwall and Devon, tin, copper, tungsten and other non-ferrous metal deposits bear some relation to the Hercynian posttectonic granites. In areas of Lower Palaeozoic slaty rocks in central and northern Wales, the Lake District and the southern Uplands of Scotland, lead, zinc, and copper deposits occur, but many of them were emplaced in post-Carboniferous times. The Lower Carboniferous uplands of Mendip, north Wales, north Derbyshire and the northern Pennines are all highly mineralized, with lead and zinc, and in the Pennines fluorite, barite and witherite also appear in quantity. All deposits so far mentioned are epi­genetic, i. e. emplaced later than the enclosing rocks. This also applies to the hematite deposits formerly worked in Carboniferous Limestone in west and south Cumberland and Furness, and those now working in south Wales. Mineral deposits which form part of the enclosing rock-sequence include the Permian dolomite–anhydrite–halite–sylvine evaporites of northeast England; the Triassic halite deposits particularly in Cheshire; and the siderite–chamosite ironstone in the Jurassic belt extending from Cleve­land through Scunthorpe to Banbury. In addition, large tonnages of hard rocks are quarried in Scotland, Wales, northern and north-midland England and the Cornubian peninsula; and sand and gravel is worked from Pleistocene glacial deposits and Holocene alluvials, especially in the London district, East Anglia and the Trent valley.

‘Curiosity’, ‘dangerous adventure’, and ‘the perilous point of honour’

2020 ◽  
pp. 50-71
Author(s):  
Simon Bainbridge
Keyword(s):  
Case Studies ◽  
Lake District ◽  
Romantic Period ◽  
Scottish Highlands ◽  
North Wales ◽  
Mountain Summit ◽  
Specific Identity

This chapter investigates how reaching a mountain summit came to be seen as a meaningful act in the Romantic period. It examines three case studies of texts by pioneering climbers who played significant roles in the development of mountaineering and who can be seen as representatives of different emerging cultures of ascent. Joseph Budworth’s A Fortnight’s Ramble to the Lakes (1792 and 1810) illustrates how mountaineering developed as a ‘curious’ pursuit. William Bingley’s A Tour Round North Wales (1800) and North Wales (1804) reveal how a culture of mountain ‘adventure’ evolved out of the scientific pursuit of botany. John MacCulloch’s The Highlands and Western Isles of Scotland (1824) shows the developing conception of mountaineering as a heroic pursuit that enabled those undertaking it to claim a specific identity, articulated particularly through the language of chivalry. The case studies illustrate mountaineering’s development in the Lake District, Snowdonia, and the Scottish Highlands.

Major folds affecting the Lower Old Red Sandstone Group at Lligwy, Anglesey, North Wales, and their regional significance

2011 ◽  
Vol 148 (4) ◽  
pp. 644-654 ◽  
Author(s):  
JACK E. TREAGUS ◽  
SUSAN H. TREAGUS ◽  
NIGEL H. WOODCOCK
Keyword(s):  
Lower Devonian ◽  
Lake District ◽  
Red Sandstone ◽  
Angular Unconformity ◽  
Isle Of Man ◽  
Iapetus Ocean ◽  
North Wales

AbstractThe Old Red Sandstone on Anglesey, North Wales, presumed Lower Devonian in age, is folded and locally cleaved, but the intensity of this deformation has previously been understated. We describe two S-verging anticline–syncline pairs, one with a strongly overturned middle limb, their associated minor folds and an axial-planar cleavage. The intensity of the deformation calls into question a proposed link to Variscan fault displacements, and the angular unconformity below the Old Red Sandstone precludes the deformation being part of a continuous ‘late Caledonian’ phase. We consider this deformation of the Old Red Sandstone to be mid-Devonian, correlating with the Acadian phase in mainland Wales. It is predated by a Silurian shortening deformation on Anglesey that is possibly related to the closure of the Iapetus Ocean, absent in mainland Wales and the Lake District, but perhaps preserved also on the Isle of Man.

The Caledonoid faults of northern Lleyn (North Wales)

1970 ◽  
Vol 107 (3) ◽  
pp. 235-247 ◽  
Author(s):  
W. E. Tremlett
Keyword(s):  
Volcanic Rocks ◽  
Strike Slip ◽  
Metamorphic Rocks ◽  
Red Sandstone ◽  
North Wales ◽  
Dextral Strike Slip

SummaryEvidence of substantial dextral strike-slip displacements along the Caledonoid fault-set of northern Lleyn is revealed by the distribution of Pre-Cambrian igneous and metamorphic rocks, Ordovician volcanic rocks and Caledonian ‘early granodioritic’ intrusions. These apparently occurred prior to some smaller sinistral strike-slip movements which left total net dextral displacements of 91/2 km. Both types of movement were completed before the Caledonoid faults were disrupted by NNW sinistral faulting and more intrusions of Lower Old Red Sandstone age were emplaced.

VI.—The Altered Clastic Rocks of the Southern Highlands, their Structure and Succession

1896 ◽  
Vol 3 (4) ◽  
pp. 167-174 ◽  
Author(s):  
Peter Macnair
Keyword(s):  
Red Sandstone ◽  
North West ◽  
Scottish Highlands ◽  
Clastic Rocks ◽  
The North

In the following paper I propose to give an account of some observations upon the structure and succession of the rocks of the Southern Highlands. By the term Southern Highlands I mean that part of the Scottish Highlands lying immediately to the north-west of the great line of fault separating the older rocks of the former area from the younger Old Red Sandstone series of the low grounds.

II.—The Magnesian Limestone and New Red Sandstone in the Neighbourhood of Nottingham

1877 ◽  
Vol 4 (4) ◽  
pp. 155-156
Author(s):  
W. T. Aveline
Keyword(s):  
Geological Survey ◽  
Lake District ◽  
Red Sandstone ◽  
Geological Map ◽  
The Subject ◽  
The Government ◽  
Made In

Since the Government Geological Survey of the country around Nottingham was made in the year 1859, and the Explanation on the Geological Map Quarter-sheet 71 N.E. was written in 1861, papers by local geologists have been written, stating that in the neighbourhood of Nottingham a perfect conformity existed between the Magnesian Limestone and the New Red Sandstone. This being totally at variance with conclusions I came to when I surveyed that country, I have been for some time past desirous to say a word on the subject, but being deeply occupied with the old rocks of the Lake district, I have put it off from time to time. I felt little doubt in my mind, when surveying the neighbourhood of Nottingham, that there was a considerable break between the Magnesian Limestone and the New Red Sandstone, and this opinion was completely confirmed as I continued my survey northwards through Nottinghamshire into Yorkshire.

An Early Devonian lake and its associated biota in the Midland Valley of Scotland

1995 ◽  
Vol 86 (4) ◽  
pp. 233-246 ◽  
Author(s):  
N. H. Trewin ◽  
R. G. Davidson
Keyword(s):  
Volcanic Activity ◽  
Fish Fauna ◽  
Early Devonian ◽  
Red Sandstone ◽  
Drainage Patterns ◽  
Terrestrial Environments ◽  
Climatic Regime ◽  
Lake Floor ◽  
The 19Th Century ◽  
Green Clay

ABSTRACTThe Tillywhandland fish bed of the Lower Old Red Sandstone in the Strathmore area of the Scottish Midland Valley accumulated in a lake, here called Lake Forfar, which was created suddenly following a period of fluvial deposition. Lake creation may have been due to basin faulting or the disruption of drainage patterns by contemporaneous volcanic activity. The fish bed laminites accumulated in a hydrologically open lake under a seasonal climatic regime. When fully developed, laminites comprise repeated quadruplets of clastic silt/carbonate/organic/green clay–shale laminae averaging 0·5 mm in thickness. Following 2000 years of laminite deposition an increasingly silty succession with thin current-rippled sandstones provided the lake-fill.The fish fauna is dominated by Mesacanthus and Ischnacanthus with rare Euthacanthus, Parexus, Climatius, Vernicomacanthus and Cephalaspis. Most fish carcasses were partially decayed before deposition in the laminites on the poorly oxygenated lake floor. Abundant coprolites are the result of predation on Mesacanthus and small Ischnacanthus, probably by larger Ischnacanthus. Arthropods present include eurypterids (Pterygotus), washed in as near complete exuviae and fragments, and millipeds which were washed in from surrounding terrestrial environments along with plants, of which Parka and Zosterophyllum are common. Bioturbation indicates that conditions were not permanently anoxic during deposition of the laminites.Comparison of our collections with the Mitchell Collection accumulated in the 19th century indicates that Tillywhandland Quarry was the main source of specimens in laminite lithologies labelled ‘Turin Hill’.

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