Millstone Grit Series Research Articles

Potassium and argon loss patterns in weathered micas: Implications for detrital mineral studies, with particular reference to the triassic palaeogeography of the British Isles

Potassium-argon ages are reported for 16 muscovite and 14 biotite samples separated from Triassic sandstones of the Manx-Furness, Carlisle-Solway Firth and Lough Neagh-Arran Basins. Disturbance of the K-Ar isotopic system in these minerals during weathering, erosion, transport and lithification is discussed and loss of potassium shown to be as important a parameter as argon loss. Published data from tropical weathering profiles are used to establish the pattern of loss for these two elements during the formation of clay minerals from biotite, the data being displayed in a “potassium-argon loss diagram”. The loss curve so produced is then used to interpret our new biotite data and previously published age data for detrital biotite from the Cheshire Basin. The limit of interdigitation of northerly and southerly derived materials in the Irish Sea Basins is shown to lie north of the Fylde district of Lancashire. Age data from detrital muscovite are used to establish a potassum-argon loss curve for muscovite. The features of the two curves are markedly similar. Little effect on the apparent K-Ar age is observed until about 20% loss of potassium occurs. At this point massive argon loss takes place with little loss of potassium, due to either potassium “stabilisation” or structural expansion. The suitability of micas as K-Ar chronometers may be a consequence of the correlated potassium-argon loss rather than intrinsic high argon retentivity. If both mica curves are applied to detrial micas of the Namurian Millstone Grit series, a source area of age of ca. 900 Ma is indicated for both muscovite and biotite, indicating a probable pre-Cambrian age source area, probably in Scandinavia.

THE BASE OF THE NAMURIAN AND OF THE MILLSTONE GRIT IN NORTH-EASTERN ENGLAND

Summary During the last few years evidence has been accumulating which has indicated that the junction between the Lower and Upper Carboniferous, the Viséan–Namurian junction, lies in the vicinity of the Great Limestone at the base of the Upper Limestone Group. The zonal evidence for the position of this boundary is reviewed and five new goniatite records from this part of the succession are described. Two have a direct bearing on the boundary problem— Cravenoceras leion Bisat, the basal goniatite of the Namurian, from the shales above the Great Limestone at Greenleighton quarry, Northumberland, and Cravenoceras aff. malhamense (Bisat) from the shales above the Little Limestone in Swinhope Burn, East Allendale. The base of the Namurian is now shown almost certainly to lie between the Four Fathom Limestone and the Great Limestone; the base of the latter is shown to be the nearest suitable mapping horizon for the base of the Millstone Grit Series.

Cross‐strata of the Rough Rock (Millstone Grit Series) in the pennines

AbstractThe Rough Rock is the highest sandstone horizon in the Millstone Grit Series (Namurian) in northern England. It is about 70 feet thick and outcrops over an area of some 4,000 square miles. Modal analyses show that it is an arkose, with about 20% of felspar (mainly microcline perthite) and many quartzose rock pebbles. Cross‐stratification is very common, occurring in sets mostly between one and three feet in thickness. The orientations of 1738 cross‐strata, measured at 301 localities, show that the currents flowed mainly southwestwards.It is suggested that the arkoses were deposited on an extensive and nearly horizontal floor just above sea level, and that sediment was distributed not by one but by many rivers, perhaps aided by flash floods.

X.— A Vertical Force Magnetic Survey over part of the Dusk Water Fault of North Ayrshire

1. Introduction The area comprises the ground flanking the Dusk Water Fault at Auchenmade, near Dalry, North Ayrshire (Fig. 1), is rather less than one square mile in size, and covers a section of the fault just over one mile long. The regional geology is complicated by extensive faulting and folding, but in essentials is represented in Fig. 1. Just east of Dalry, the ground north-west of the Dusk Water Fault is occupied by a south-plunging syncline in the Carboniferous Limestone Series with Millstone Grit (and a small outlier of Coal Measures) near the axis. The Millstone Grit Series consists mainly of basic lavas (about 40 ft. thick at Auchenmade), and crops out in the northern part of the surveyed area. It is underlain by strata of the Upper Limestone and Limestone Coal Groups; the latter also crops out between the Waterside and Auchenmade Faults. South of the Dusk Water—Auchenmade Fault, basic lavas of Calciferous Sandstone age (the visible base of the local succession) form an outcrop in the east of the surveyed area and are succeeded southwards by younger rocks. Thus the Dusk Water—Auchenmade Fault, the most striking structural feature on the map, bisects and distorts the basically simple pattern of a broad south-plunging syncline, bringing rocks at the base of the succession on its southern side into proximity with rocks at the top of the succession on its northern. The only important sequences of known rocks of high magnetic susceptibility in the district are the basic lavas which This 250-word extract was created in the absence of an abstract

A deep borehole for oil at croxteth park, near liverpool

AbstractA deep borehole has recently been drilled in search of oil and natural gas near Croxteth Park, Liverpool. The borehole penetrated Recent and Glacial deposits and a minimum of 1,306 ft. of Permo‐Triassic sandstones before crossing the large Croxteth Fault and entering rocks of the Millstone Grit Series. Thereafter, a sequence of strata extending from almost the top of the Millstone Grit down to beds in the upper part of the Carboniferous Limestone Series has been proved for the first time in the area. The limestones have yielded a large fauna.

A GUIDE TO THE GEOLOGY OF THE CLIVIGER VALLEY, NEAR BURNLEY, LANCASHIRE

I. Introduction The Cliviger valley or gorge is a prominent feature near Burnley in Lancashire, trending in a south-easterly direction to Todmorden in the West Riding of Yorkshire. The valley is about six miles in length, followed by a railway and a road (A.646). Some four miles from Todmorden, near Windy Bridge, two streams rise, the Lancashire and Yorkshire Calders, and flow in opposite directions to the Irish Sea and to the North Sea. The area described is bounded on the north-east by the Long Causeway as far as Redmires Dam ( 930277 ) and thence to Hole Bottom and Todmorden. The limit on the south-west extends along the summits of Carr and Craggs Moor ( 895255 ), Heald Moor ( 885265 ), Thieveley Pike ( 872272 ), and Crown Point ( 849288 ). The valley is a striking feature, in parts of rugged aspect, and is some 500 feet deep at Windy Bridge, with a canyon-like section—the effect of its former utilisation as a direct glacial overflow channel. It has thus been over-deepened and consequently the tributary streams enter it in a series of gorges with characteristic rejuvenation phenomena; the streams are actively eroding their beds and provide good natural sections except where the valley sides are obscured by landslips. These deep V-shaped valleys contrast greatly with the somewhat featureless expanses of the surrounding moors, although they are rarely mentioned in the general descriptions of the Central Pennines. The beds of the Millstone Grit Series give rise to a fairly continuous escarpment along the south-west side of the …

Growth and variation in the non-marine lamellibranch fauna above the Sand Rock Mine of the Lancashire Millstone Grit

Summary Shells from a recently discovered band of non-marine lamellibranchs above the Sand Rock Mine (near the top of the Millstone Grit Series) west of Wigan have been statistically investigated at four localities. The dominant fauna, Carbonicola exporre ta gar and variants, is systematically described and the variation analysed. The affinity of this fauna appear to lie with Carbonicolidae characterizing lower horizons in the Namurian, whereas a second group of shells, much less commonly represented in the band, shows similarity with the succeeding faunas of Anthraconaia bellula (Bolton) and Carbonicola fallax Wright. The shells range in length between 3 and 49 mm. Studies in the growth of both groups include the measurement of early growth-lines in the larger individuals and reveal considerable changes in the proportions of the shell. For the mean relative growth of communities evidence points to a linear relationship between the logarithms of shell height and length. This cannot yet be fully defined. Petrological differences in the shell-bearing stratum have been investigated by Professor K. C. Dunham. It is shown, with the further support of chemical analysis, that a progressive decrease in the percentage of carbonaceous matter in the fossiliferous shale is accompanied by increase in the thickness of the band, decrease in the number of shells it contains per unit thickness, decrease in the mean size of the shells and a slight change in their relative growth-rates with respect to height and length. The latter two points indicate stunting of the fauna. The first three changes are considered to be the result of increased sedimentation. Evidence is submitted for considering the C. exporrecta faunas to have been invaded by those of the second shell group. Detailed collecting at Upholland Station cutting reveals similarities in the succession of the latter faunas to that characterizing the base of sedimentary cycles in the Soft Bed—Bassy Mine succession of the lower lenisulcata Zone. Differences in the two horizons are discussed. No internal features of the shell are revealed in the second group, but numerous cases of perfect gradation between Carbonicola -like and Anthraconaia -like forms confirm previous observation in the lower lenisulcata Zone. The evolution of certain species of Carbonicola from a group in which the genera Carbonicola and Anthraconaia were apparently not yet distinct is briefly discussed.

X.— A Boring through the Lugar Sill

Introduction In 1917 the author described the Lugar Sill in some detail and made out a descending succession of teschenite, theralite, picrite, peridotite, and finally teschenite again at the lower contact.1 It then seemed a perfect example of gravity-differentiation by the sinking of olivine crystals within the frame provided by the upper and lower teschenite layers, with a gradual increase of density downwards until a maximum was reached about two-thirds of the way down. Even at the time the paper was presented this explanation was seen to be too simple for the facts, and an alternative hypothesis of successive intrusion from an already-differentiated body of magma was formulated. This explanation is supported by the data from a boring through the sill at Mortonmuir near Cronberry, about a mile distant from the best surface exposures at the confluence of the Bellow and Glenmuir Waters. The present paper is intended to describe the succession of rock types shown in the Mortonmuir boring, to compare it with that of the exposed section, and to develop further the theory of successive intrusion as an explanation. The author is indebted to the Geological Survey of Scotland, and to Dr. Murray Macgregor, lately Assistant-Director, for this opportunity, and for submitting to me the 45 rock specimens collected by Mr. W. Manson from the cores. The Lugar Sill and its probable western continuation, the Glaisnock Sill,1 are intruded into sandstones and shales of the Millstone Grit Series.2 To the east of Lugar its horizon passes downwards until This 250-word extract was created in the absence of an abstract

The Middle Grits of Derbyshire

The River Amber on its way from the Erewash Valley Coalfield to its junction with the Derwent near Ambergate crosses the upturned edges of the Millstone Grit Series. Near the point where the river enters the grit belt at Bullbridge a boring for water was put down in the grounds of the Amber Dye Works during the latter half of the year 1936. My thanks are due to the directors of Stevensons (Dyers), Limited, for giving me every facility for examining the core, and to Mr. S. G. Clift for assisting me in the examination and in collecting. My thanks are also due to Dr. C. J. Stubblefield for valuable criticisms and suggestions during the writing up of this note.

The stratigraphy, structure and mineralization of the Greenhow mining area, Yorkshire

Summary The primary object of the work was the investigation of the geological environment of the galena-fluorite-barite deposits. The Carboniferous Limestone Series, over 1400 feet in maximum thickness, was mapped in six divisions covering faunal horizons from ?C 2 S 1 up to and possibly above D 2 . The Millstone Grit Series rests unconformably on horizons from the Davidsonina [ Cyrtina ] septosa band in D 1 up to beds with Orionastraea , the relations being ascribed to a pre-Millstone Grit uplift, possibly domal in form, accompanied by faulting. Within the Millstone Grit the "Top Limestone" (renamed the Cockhill Limestone) was proved to be characterized by Cravenoceras cowlingense (E 2 ). Two higher marine horizons, well known elsewhere, were established here by many exposures : the Colsterdale Marine Beds, characterized by Cravenoceras nitidum (E 2 ), seen in the same section as the Cockhill Limestone, and the glauconitic Cayton Gill Beds. A structure-contour map based on horizons in the Millstone Grit mapped at surface and underground shows that the anticline in the southern part of the area, trending east-north-east, has an amplitude of about 1000 feet, and that a series of domes and basins have been developed along its crest. The North Craven Fault, runniilg along the southern flank of the anticline, is a complex fracture-belt enclosing a tight syncline in the western part of the area, degenerating eastwards into a small strike-fault. The eastern half of the Bycliffe Vein-system is mineralized up to the Cayton Gill Beds but the remaining veins are mineralized only in the Carboniferous Limestone. The most important ore-shoots are found in the upper division of D l , in limestone underlying either shales low in the local D 2 or the basal shale of the Millstone Grit, depending on the position of the unconformity. Less important ore-shoots are found at various horizons from ?C 2 S 1 up to D 1 . It is suggested that extension of mineralization in depth beyond the limits so far revealed is possible in the case of ore-shoots related to shale overlying D 1 limestone. There is a crude zonal arrangement of minerals. Palaeontological notes are included on Hederella cf. chesterensis (of a suborder new to Britain) and on two new forms, Productus (Eomarginifera) tissingtonensis cambriensis and Eumorphoceras bisulcatum grassingtonensis .

The Paper Industry of the Pennines

The Physical Background THE Pennine Highland is the dominant feature in the relief of North England, and has a length of about 150 miles and a mean width of 50 miles. That part of it south of Craven Gap may be divided into two sections; from High Peak northwards the surface rocks are composed chiefly of the Millstone Grit series, while to the south of Rushup Edge the landscape is formed principally of the Carboniferous limestones. This essay is concerned primarily with the grit area and the valleys on the east and west which have been cut into it.

A BORING IN THE MILLSTONE GRITS, ROD MOOR, SHEFFIELD

In 1933 a borehole was sunk in the upper part of the Millstone Grit Series of the grit moors west of Sheffield from the base of the Coal Measures to well within the Rivelin or Main Third Grit. The total thickness passed through was 465½ feet. I have been enabled to examine the cores by the courtesy of the Wortley Rural District Council. Mr. F. E. G. Watson, of Le Grand, Sutcliff and Gell, the boring engineers, has taken a continued interest in the investigation, and I wish to thank him for the kind assistance that he has given. My thanks are due to Prof. W. G. Fearnsides, F.R.S., for his kindness in allowing me to carry out office work in the Department of Geology at Sheffield University. The borehole site (at 1,050 ft. O.D.) is in the north corner of the railed-off portion of the field on the flank of Rod Moor, half a mile north-west of Load Brook, and six miles west of the centre of Sheffield. [Yorks. 6″ map, 293 N.E.] Originally a borehole was commenced near the track to Load Brook about 1,000 ft. SSE. of the final hole, but after passing through several feet of massive sandstone a NW. fault throwing down to the NE. was struck, and the hole was abandoned. The succession passed through in the second hole was as follows: — | Succession. | Description | Thickness | Depth | |:----------------------------------------------------------------------------- | ----------- | --------- | ----- | --- | | | | ft. | in. | ft. | in. | | Lower Coal Measures. (Pot clay marine band at base not noted by borer but ... | | | | | |

THE GLACIAL GEOLOGY OF NIDDERDALE

Introduction. The catchment basin of the River Nidd, from its source on Great Whernside to its termination at Nun Monkton, approximately forty-five miles in length and covering an area of about 450 square miles, presents interesting features of superficial geology which will be considered in some detail. The valley is completely separated from the adjoining dales of the Cover, Ure, and Wharfe in its upper reaches by high peat-covered moorland, attaining a height of 2,310 feet O.D. The solid geology of the area is largely dependent on the Pennine Anticline so that sandstones and shales of the Millstone Grit Series outcrop in Upper Nidderdale; Magnesian Limestone near Knaresborough; and Keuper and Bunter Sandstones of Triassic age east of Cowthorpe. Yoredale limestones and shales occur in the valley bottom: ( a ) from Angram to Scar House; ( b ) near Manchester and Goyden, pot-holes below Lofthouse Moor; and ( c ) at the junction of the Nidd and How Stean Beck near Lofthouse village. Lower Carboniferous rocks again outcrop near Harrogate, due to a subsidiary anticline. South of Ripley there is an outlier of Permian Magnesian Limestone. A lithologically interesting outcrop is a particular band of blue chert, occurring in situ above Angram just below 1,200 feet O.D. in the Yoredale beds. No igneous or metamorphic rocks are known to occur in Nidderdale. Previous workers on the glacial geology of the area are Professor H. Carvill Lewis,1 Professor P. F. Kendall,2 and others who will be noted in due course. Evidences of Glaciation. I. Drift.—The ...

“Farey's Grit.”

The present paper deals briefly with the historical aspect of the boundary between the Pendleside Series and the Millstone Grit Series in the Roches district and surrounding country of North Staffordshire some 4 miles north-east of Leek; and particularly with the term “ Farey's Grit ”. It seems to me probable that the difficulties as to limitation and classification of these divisions of the Carboniferous System are by no means limited to the small area with which I am familiar. The substance of this paper is derived from the works listed at the end, and has formed itself as a result of attempts to map the rocks in detail.

The Petrography of the Millstone Grit of Yorkshire

The term ‘Millstone Grit’ is applied to a series of beds which attain a thickness of 5500 feet in Lancashire, consisting of conglomerates, grits, sandstones, and shales with occasional thin impure limestones and beds of chert. It occupies a position in the geological sequence between the Yoredale or Pendleside Group and the Coal Measures. For the purposes of this investigation the base of the Millstone Grit in West and North-West Yorkshire has been taken at the base of the Ingleborough Grit, following the precedent of the Geological Survey as pointed out in the Memoir on the Ingleborough District, 1890, pp. 74–75. Since this is a coarse grit, easily traceable on account of its lithological characters and the bold escarpments to which it gives rise, it forms a good datum-line. The top of the series has been taken at the top of the Hough liock, where it can be seen to be overlain by the Lower Coal Measures, as at Whitehall Quarries, Horsforth, near Leeds. However, as no questions of correlation are involved in this work, the exact delimitations of the various beds is a matter of minor importance. The Millstone Grit Series covers an area in Yorkshire alone of no less than 840 square miles, and is important physiographically, as it forms the capping of most of the hills of the Pennine Chain, such as Mickle Fell. Whernsicle, Ingleborough, Penygent, etc., and by its presence there preserves the more easily denuded strata below from a more rapid destruction. Economically the

The Paradoxidian Fauna of a Part of the Stockingford Shales

I. Introduction and Previous Literature. The strata which form the subject of this paper make up a small part of the Cambrian succession cropping out near Nuneaton, in the very heart of the Midlands. Here, an inlier of Cambrian age forms a narrow belt of country about 9 miles long, running in a general north-westerly and south-easterly direction, between the towns of Atherstone and Bedworth. On the north-eastern side lies the rolling plain of down-thrown Trias, while on the opposite, or south-western side, the highly-dipping Cambrian shales are unconformably overlain by the Coal Measures. In the early Geological Survey publication of 1859, by H. H. Howell, these lower strata were not differentiated from the overlying Carboniferous System. The Lower Cambrian Quartzites were correlated with the Millstone Grit Series, while the immediately overlying shales were included in the Coal-Measure Shales proper. The next noteworthy contribution was the brilliant work of Samuel Allport in 1879, on the intrusive igneous rocks. To these he applied the term ‘diorites,’ distinguishing them from the doleritic type that usually occurs in the Carboniferous of the Midlands. However, it was not until 1882 that Prof. Charles Lapworth and W. J. Harrison, noting the similarity of the quartzites of Lickey and Hartshill, investigated the area, and proved the bedded nature of the Lower Caldecote igneous rocks. Finally, by the discovery of Cambrian Lingulæ in the overlying shales at Stockingford Cutting, Prof. Lapworth was able to establish the true age of these beds. The same author divided the succession

NOTES ON A JUNCTION OF COAL MEASURES AND MILLSTONE GRIT AT HAWKESWORTH QUARRY, HORSFORTH

Read 20th February, 1908. Manuscript received 20th February, 1908. Over a considerable tract of country, from the neighbourhood of Thorner to Horsforth, the Yorkshire Coalfield is cut off to the north by a fault, or series of faults, which brings in the Millstone Grit. To the north of this line of fault there are several outliers of Coal Measures which exhibit the normal junction with the Millstone Grit. These are at Chapel Allerton, Hawkesworth Quarry, Rawdon, and Baildon, and it is in one of these, viz., at Hawkesworth Quarry, that the exposure described in the present note occurs. The section in the quarry is continued to the neighbouring railway cutting and shows the Coal Measure shales dipping to the southward and resting upon the “Rough Rock,” the uppermost member of the Millstone Grit series. Both the shales and grits are quarried, the former for brickmaking and the latter being an excellent building stone. In the course of the removal of the overlying shales, the surface of the Millstone Grit has been exposed over a considerable area, and during a recent visit of the members of the Leeds Geological Association I noticed that this surface presented a very curious appearance, consisting of a number of hummocks, flat on the top, with steep sides, and separated from one another by hollows, which on investigation I found to be old water channels. The whole surface resembled in a striking manner the sandbanks which form the submerged delta of the Mersey, and which are ...

IV. The Extension Westwards of the Necropolis Intrusion

Some time ago Mr. Macnair, F.R.S.E., in exhibiting the Pratt collection of microscopic slides of dolerite recently presented to the Corporation, commented on the resemblance that a section of dolerite from Miller Street bore to the well-known dolerite of the Necropolis. Considerable doubt was expressed as to the identity of the two rocks, and the opinion was given that the Miller Street occurrence was a dyke. Among those who have conducted excavations in this region also this occurrence of whin is known as the Miller Street dyke. The object of the present paper is to examine the evidence bearing on the question, and to endeavour to establish the probability of the Necropolis intrusion extending as far west as Miller Street. There is, of course, no opportunity of obtaining direct field evidence on the matter, as the area in question is completely built up, but indirect field evidence will be given, showing that dolerite occurs in several places between Miller Street and the main body of the intrusion. The Necropolis intrusion consists of a huge mass of dolerite intruded into the Millstone Grit series, and extending for some miles east of Glasgow. The intrusion seems to stop rather abruptly just at the Necropolis, but on the Survey 6-inch map a detached mass of dolerite is shown some distance west of the main rock. From information available since the map was published, it can be shown that this part is not quite accurate. The tunnel of the North British Underground Railway should This 250-word extract was created in the absence of an abstract

THE EVOLUTION OF THE DON RIVER-SYSTEM

Whilst making a study of river development in Yorkshire a few years ago my attention was attracted to the Don, whose peculiarly erratic course evidently had an interesting history. My surprise was great when no reference to this problem could be found in the geological literature to which I had access. The present paper is an attempt to explain this interesting physical history. I.—The Don River-System The River Don, between its source in the moorlands of the Pennine Chain and its outflow into the Ouse at Goole, has a roughly semi-circular course (Pl. LIII.). Rising in the Middle Grits of the Millstone Grit Series, at an elevation of 1,500 feet above O.D., it flows eastwards to Dunford Bridge (1,000 feet), where it is reinforced by powerful feeders north and south. It then flows eastwards over the Rough Rock, across the strike of the beds and the main faults, and enters the Lower Coal Measures at Hazlehead. At Thurlstone it cuts a gorge through the Grenoside Rock, and then traverses the overlying Penistone sandstones and shales. At Penistone the Don receives the waters of Scout Dike, which, from its source in the moorlands, runs direct east as a dip river (Broadstone Dike), to Ingbirchworth, and then takes a sudden bend to the south-east along the strike of the Penistone sandstones. At Penistone the Don ceases to be a dip river and, changing its direction, runs to the south-east along the strike of the Penistone sandstones in a V-shaped valley, the ...

RECORDS AND COMPARISON OF THREE DEEP BORINGS IN THE MILLSTONE GRITS AT HALIFAX

Three deep borings have been sunk in the dip slope of the Grit Rocks of Halifax in search of an increased supply of water during the past few years, and in return for such geological information as I have been able to give, I was allowed to watch the operations and make notes of the strata passed through. Halifax is built on the Rough Rock, the top member of the Millstone Grit series. At the lowest part of the town, a little to the east of the railway line, the Grit series pass under the Lower Coal Measures which form the bold escarpment and conspicuous physical feature to the east of the town. From here the Rough Rock, which has a general datum level of about 400 feet where it disappears under the Coal Measures, rises at an angle of about 2° to the west and north-west to over the 1,000 feet datum. Further to the west and north-west of Halifax, Luddenden valley cuts through the various members of the Grit series, almost down to the Kinderscout rocks at the base. On the easterly terraced sides of this valley, and on the moorlands to the north, the middle series of the Grit rocks are exposed, and doubtless gather a considerable amount of surface water, which following the dip, and directed and held by the impervious shales above and below, passes under Halifax at varying depths below the surface rocks. The Rough Rock, as its name would suggest, is generally coarse...