Lower Magnesian Limestone Research Articles

Radon in the Creswell Crags Permian limestone caves

An investigation of radon levels in the caves of Creswell Crags, Derbyshire, an important Site of Special Scientific Interest (SSSI) shows that the Lower Magnesian Limestone (Permian) caves have moderate to raised radon gas levels (27-7800 Bq m −3) which generally increase with increasing distance into the caves from the entrance regions. This feature is partly explained in terms of cave ventilation and topography. While these levels are generally below the Action Level in the workplace (400 Bq m −3 in the UK), they are above the Action Level for domestic properties (200 Bq m −3). Creswell Crags has approximately 40,000 visitors per year and therefore a quantification of effective dose is important for both visitors and guides to the Robin Hood show cave. Due to short exposure times the dose received by visitors is low (0.0016 mSv/visit) and regulations concerning exposure are not contravened. Similarly, the dose received by guides is fairly low (0.4 mSv/annum) due in part to current working practice. However, the risk to researchers entering the more inaccessible areas of the cave system is higher (0.06 mSv/visit). This survey also investigated the effect of seasonal variations on recorded radon concentration. From this work summer to winter ratios of between 1.1 and 9.51 were determined for different locations within the largest cave system.

The statistical modelling of the grain size distributions of cave sediments using log skew laplace distributions: Creswell Crags, near Sheffield, England

Abstract This paper describes the statistical modelling of cave sediment size data using log skew Laplace distributions. The sediment samples were obtained from excavations in three archaeologically-important, palaeolithic deposits in the Creswell Crags Caves, which occur in the infrequently studied Lower Magnesian Limestone (Permian) bedrocks, east of Sheffield, England. Theoretical and practical justifications for employing this and other types of statistical distribution to model grain size data are briefly reviewed. Three independent and one summary descriptor based upon parameter measures derived by fitting log skew Laplace models to cave sediment grain size data are then used to explore the relationships between sediment location—specifically distance of the sample from the cave entrance(s) in three caves which differ in their geomorphic complexity. In the most complex cave—Robin Hood's Cave—broadly defined “groupings” or “sediment trajectories” were detectable in 3D displays of the parameter values for samples from individual “columns” of the sampled cave sediments. The relatively simple “sac” cave (Pin Hole Cave) appears to show relatively simple “zonal” trends in the descriptors, with variation in the outermost part of the chamber being primarily responsible for the trends observed. Zonal trends were also suggested, but less clearly, by some of the independent descriptive parameters in the more complex Church Hole Cave, but in this case it was the properties of the innermost samples that were responsible for much of the apparent variation detected. On the basis of this statistical modelling and the associated exploratory data analysis, it is hypothesized that textural variations in these three caves can be provisionally “disaggregated” into at least two complex elements. The first manifests itself in zonal variations which appear to relate, directly or indirectly, to the effects of increasing distance from these cave mouths (essentially akin to the ideas of Schmid, 1969 , Science in Archaeology, pp. 151–166. London: Thames and Hudson); the second discloses itself in more location-specific variations which themselves reflect the local sedimentary circumstances of that particular site within Robin Hood's Cave (similar to the ideas of Butzer, 1971 , Environment and Archaeology: An Ecological Approach to Prehistory. Chicago: Aldine).

Mineralization in Upper Permian carbonates at outcrop in eastern England

Summary Upper Permian carbonates in eastern England at outcrop feature subeconomic syngenetic and epigenetic Pb-Zn-Cu-Fe-Ba-F mineralization. Pb-Zn-Fe sulphides occur in vugs and breccias of sedimentary origin whereas much barite replaces the host carbonate. Vein mineralization is rare. The majority of occurrences are within the Cadeby Formation (Lower Magnesian Limestone; EZ1 Ca). More than 70 occurrences of mineralization have been recorded, clustered on centres at Farnham, Bramham, Edlington and Mansfield. Host carbonates at the first three of these centres overlie major cross-cutting structures in pre-Permian strata; these structures were possible flow channels for mineralizing solutions. Mineralization in the Mansfield area can be explained by the upwards leakage, on a broad scale, of formation fluids from Carboniferous strata that overlie the South Pennine basement high.

The diagenetic history of Cadeby Formation carbonate (EZ1 Ca), Upper Permian, eastern England

Summary The Upper Permian Cadeby Formation (formerly the Lower Magnesian Limestone) crops out from North Yorkshire to Nottinghamshire in eastern England. The Cadeby Formation comprises shallow water carbonates within which penecontemporaneous, eogenetic, mesogenetic and teleogenetic diagenetic events can be defined. Penecontemporaneous events included facies-controlled dolomitization and evaporite calcitization. Pervasive dolomitization, largely independent of facies, was eogenetic. Late eogenetic to early mesogenetic events were dominated by replacive and pore-filling anhydrite crystallization. Both pervasive dolomitization and subsequent anhydrite formation occluded porosity. Other mesogenetic events were of local effect only. Anhydrite to gypsum transformation, together with evaporite dissolution and carbonate leaching, dominate the later near-surface, or telogenetic, events.

The application of cathodoluminescence in relative dating of barite mineralization in the Lower Magnesian Limestone (Upper Permian), United Kingdom

The application of cathodoluminescence in relative dating of barite mineralization in the Lower Magnesian Limestone (Upper Permian), United Kingdom

A BARYTE-GALENA VEIN IN THE MAGNESIAN LIMESTONE AT WHITWELL, DERBYSHIRE

Summary Temporary sections at Whitwell, Derbyshire, have exposed a baryte-galena vein within the Lower Magnesian Limestone. Massive, crystalline, pink and purple varieties of baryte are the principal components of the vein. Extensive metasomatic wall-rock alteration of oolitic limestone to baryte-dolomite rock has occurred.

Discussion

Professor K. C. Dunham said that he felt very pleased that the author’s detailed studies of the material obtained during the extensive programme of borings into the south Durham and north Yorkshire Permian were being made available for publication. Mr. Raymond’s conclusion that the Lower Magnesian Limestone was largely secondary dolomite accorded well with the position north of the Hartlepool fault, where the Lower Limestone contained a few large lenses of primary, sparsely fossiliferous calcite limestone (as at Raisby Hill) but was mostly secondary dolomite full of microcavites. The conclusion that the thick anhydrite found in the Wilton borings was mainly primary was surprising in view of previous opinions on this subject. How far could relict bedding in dolomite be trusted as a criterion of primary sulphate? It appeared that the author had decided, in the case of secondary or diagenetic dolomitization, in favour of brine sinking into the floor of the Zechstein lagoon; but it might be suggested that brines being expelled from the accumulating sediments, and rising rather than sinking, might be very effective in the conditions of higher temperature and slightly higher pressure which probably obtained during diagenesis. Dr. A. F. Hallimond said that in examining a polished section of a very pure commercial dolomite, which in thin section showed only the usual coarse and fine crystalline texture, it was possible in incident illumination to distinguish dark oval and sub-angular outlines which evidently represented the ooliths and fragments in an ordinary sedimentary limestone. This effect was apparently

PERMIAN EVAPORITES AND ASSOCIATED ROCKS IN TEXAS AND NEW MEXICO COMPARED WITH THOSE OF NORTHERN ENGLAND

Summary Marine evaporites form an important part of the Permian succession of the United States and of England. This paper gives a review of their geological setting, petrology, and mineralogy. The American mid-continental Permian reaches its greatest thickness in Texas and New Mexico. In Leonard and Guadaloupe times several relatively deep basins, flanked by shallow-water shelf areas, were connected by channels to each other and to an ocean to the south. Reef and bank deposits accumulated at times on the margins of the basins, and separated clastic basinal deposits from back-reef limestone-evaporite-red bed facies on the shelves. There was a general south-westward shift of areas of evaporite deposition as time went on, corresponding to a general retreat of the epicontinental seas. These conditions culminated in the development of the Capitan reef which surrounded the Delaware basin in Upper Guadaloupe time. Later the area was uplifted and tilted, and the basinal evaporites of the Ochoa (more than 4,000 ft. in thickness) were deposited, filling the Delaware basin, overlapping its margin, and covering part of the shelf. The back-reef evaporites are mineralogically simple, and show a marked lateral zoning from less to more soluble salts in a landward direction. The Castile evaporites (Lower Ochoa) provide a striking example of relatively deep-water deposition in an almost isolated basin relatively free from influx of terrestrial water. The Salado and Rustler evaporites (Upper Ochoa), which are mineralogically complex, are shallow-water basinal types, and include important deposits of potassium salts. The British Permian evaporites, deposited in the Zechstein Sea, represent a small part of a large area of deposition. There is little evidence of back-reef deposition in England. The evaporites appear to be predominantly shallow-water basinal types like those of the Salado Formation of Texas and New Mexico. They include the products of three major cycles of desiccation, and it is suggested that these correspond to the upper three of the four major cycles of Hanover and Thuringia. The lowest cycle of this German succession may be represented in north-eastern England by replacement bodies of anhydrite in the Lower Magnesian Limestone. Lateral change of facies in the English evaporites is marked, and includes the passage of evaporites into red beds, and of more into less soluble salts, in a shoreward direction. Potassium salts are confined to the Whitby district, where the marine Permian reaches its greatest thickness. Halite, anhydrite, and the carbonates progressively die out as the shore-line is approached. Vertical zoning includes the upward passage of less to more soluble salts, and repetitions of sequence are numerous, but large-scale repetitions within each major cycle are much less abundant than in the Salado. The mineralogy of the two regions is compared and found to be generally similar. Striking differences include the restriction of rinneite to the English evaporites, and the virtual absence of langbeinite, a major constituent of some of the Salado potash zones, in England. The English potash field is notably richer in quartz and clay, and poorer in magnesium sulphates (except in the Lower Evaporite Bed) than the American. Some minor constituents found only in the Salado may be expected to be found as exploration proceeds in England. Widespread replacement and recrystallisation have modified the evaporites of both regions, and their present mineral composition differs a great deal from that of the original deposits.

MARINE BANDS PROVED IN THE NEW BORINGS AT WENTBRIDGE AND DARRINGTON, YORKSHIRE

Read, November, 1951 Introduction. In 1906 a boring was put down about a mile east of the village of Wentbridge in search of coal. This boring started in the Lower Magnesian Limestone, entered the Coal Measures at 35 feet, and was abandoned at a depth of 990 feet after a number of coal seams had been proved, only two of which were of two feet of more in thickness (Mid. Inst. Min. Eng. 1927, pp. 365, 366). The cores from the boring were examined by E. L. Hummel and P. F. Kendall, and marine bands were proved at 220 feet, 347 feet and 895 feet. All three bands contained a varied fauna, including goniatites (Edwards and others 1940, pp. 105–108). At that time, little was known of either the distribution or the value of marine bands, so that it was only recently that an interpretation of the borehole was made. During the sinking of Upton Colliery shafts (See Fig. 1), the Shafton Marine Band was proved at 852 feet and the Mansfield Marine Band at 1380 feet (Wilson and Wray 1928, p. 6), and no other marine bands were identified. In the light of this information it was assumed that the band at 895 feet at Wentbridge was the Mansfield Marine Band, and that at 347 feet the Shafton Marine Band, whilst that at 220 feet was an additional marine band unknown throughout the Yorkshire, Derbyshire and Nottinghamshire Coalfield.2 In the first Darrington borehole only the Mansfield Marine Band ...

THE PERMIAN SEQUENCE OF SOUTH-EAST DURHAM AND NORTH-EAST YORKSHIRE

Introduction Professor Hollingworth has indicated the light in which we must view any regional or local sequence of which evaporites form a part. It is for me to discuss in general terms the geological setting of the evaporites in this particular area of Durham and Yorkshire. They occur mainly in the Magnesian Limestone formation of the Permian and in the overlying Permo-Triassic Marls. The general relationships of the various members of the sequence can be seen from the following stratigraphical table :— | | Approx. thickness in Ft. | |:--------------------------------------------------------------------------------------------------------------------------------------- | ------------------------ | | Upper Magnesian Limestone | 300–400 | | Hartlepool and Roker Dolomites. | | | Concretionary Limestones. | | | Flexible Limestones, dolomitic. | | | Middle Magnesian Limestone | 300 | | Dolomitic bryozoan and shelly reefs, with bedded but often highly brecciated dolomite replacing it on both eastern and western flanks. | | | Lower Magnesian Limestone | 200 | | Bedded dolomite and limestone. | | | Marl Slate | 0–12 | | Flaggy dolomite with fish, plants, and shell remains. | | | Yellow Sands | 0–180 | | Unconsolidated, false-bedded, round-grained sand. | | NORTH OF THE DARLINGTON FAULT Surfaces of unconformity are found at a number of different horizons in the sequence, one of the most marked being at the base of the Middle Limestone. | | Approx. thickness in Ft. | |:------------------------------------------------------------------------------------------------------- | ------------------------ | | Permo-Triassic Marls | 300–350 | | Upper Anhydrite | 10 | | Marl | 20 | | Main Salt | 100 | | Main Anhydrite | 45 | | Upper Magnesian Limestone | 75 | | Lower salt | 60 | | Lower Anhydrite | | Lower Magnesian Limestone: with much anhydrite in some areas | 600–700 | | Basement Beds, sometimes conglomeratic and with a development of the Marl Slate, especially in the west | Very variable | SOUTH OF THE DARLINGTON FAULT Definite correlation between these ...

On some new Permian fossils from the Magnesian Limestone near Sunderland

Summary Practically all the species of invertebrates in the Permian of England had been discovered before 1850, almost the only exception being the record of Chonetes davidsoni in 1864, from the Lower Magnesian Limestone at Hartley's Quarry west of Sunderland. The present paper deals with some new occurrences in these beds rather farther to the west, at Ford Quarry, Claxheugh, 2 miles west of Sunderland. They include two new species of Chonetes , one of which resembles a Spitsbergen form, a Camarophoria apparently identical with C. purdoni of the Russian and Himalayan Permian, and at least two lamellibranchs with Russian and German affinities. The early collectors paid little attention to the vertical or lateral distribution of their fossils; in the middle beds most of the fauna is crowded in a line of reef knolls in which the species die out progressively upwards. Among other localities, the classical knoll of Humbleton Hill has been re-examined, and at the top, facing west, a dolomite with the impoverished fauna, only three genera of Brachiopoda, has been found. The thrusts and other abnormal junctions of the Permian of North-East Durham have been re-investigated and their possible connexion with solution of sulphates and with faunal and reef-knoll distribution is mentioned.

On the South-Scarle Section

A t South Scarle, a point about halfway between Newark and Lincoln, au unsuccessful boring for coal some short time ago disclosed a most interesting, but, so far as its lower portion was concerned, somewhat puzzling geological section. The object of this communication is to identify, ff possible, the lower rocks passed through in these borings. The following generalized section is quoted from a paper “On a deep Boring for Coal at Scarle, Lincolnshire,” by Prof. E. Hull, F.R.S., F.G.S. (see Prec. Inst. Civil Engineers, eel. xlix. part iii.) :— Down to 26 feet in the Lower Magnesian Limestone the above classification of the Scarle cores appears to be approximately correct. Below that depth, however (1827 feet), there came up from 50 to 60 feet of a very hard dark grey to black rock, generally oolitic, though apparently untbssiliferous, the analysis of which showed it to be an argillaceous dolomite. This was succeeded by 16 feet of sandy (?) sediment too loose for cores ; then came 118 feet of grey earthy limestones or calcareous shales, with a foot or so of greenish grit or breccia at the base. Last of all (at 2020 feet), compact red or purplish-red clays with nodules of hæmatite were penetrated to a depth of 10 feet. On seeing the first specimens of the “grey earthy limestones,” Professors Ramsay and Hull both came to the conclusion, founded on lithological grounds, that these rocks were to be referred to the Lower Yoredale series. The succession below, however,

Scientific Serials

American Journal of Science and Arts, June.—The original articles in this number are:—Results of dredging expeditions of the New England Coast in 1874, by A. E. Verrill. More than 100 species new to the iauna of southern New England were secured. Most of these are northern species, but many are undescribed. A table giving nature of bottom and temperature at the surface and bottom of the sea is given.—Mr. Fontaine's paper on the Primordial Strata of Virginia is continued and concluded. At the end is given a comparison with the metamorphic crystalline rocks of the Blue Ridge.—On the occurrence of the Brown Hematite deposits of the Great Valley, by Frederick Prime, jun.—Note on some new points in the elementary stratification of the Primordial and Canadian rock of south central Wisconsin, by Roland Irving. The order for the Lower Silurian strata of Wisconsin has been generally accepted as (beginning from below) 1. Potsdam sandstone; 2. Lower magnesian limestone; 3. The St. Peter's sandstone; 4. The blue and buff limestones; 5. The Galena limestone; 6. The Cincinnati group. The succession as now made out is (beginning from below) 1. The Lower or Potsdam sandstone; 2. The Mendota limestone; 3. The Madison sandstone; 4. The main body of limestone; 5. The St. Peter's sandstone. A table of correlation is given with the Mississippi Bluffs and the Minnesota River.—On the application of the horizontal pendulum to the measurement of minute changes in the dimensions of solid bodies, by Prof. O. N. Rood.—On diabantite (a chlorite), by G. W. Hawes.—Re-discovery of double star H.I. 41, by 5. W. Burnham. It is about 46′ north of the well-known double star ψ Draconis, and is easily found without an equatorial mounting.—On the distribution of electrical discharges from circular discs, by C. J. Bell.—Examination of gases from the meteorite of Feb. 12, 1875, by A. W. Wright.—On limonite with the colour and transparency of göthite, by Prof. Mallet.—Under the head “Scientific Intelligence,” the original notes are:—On the surface geology of Ohio; On the Prototaxites of Dawson; On the Crustaceans. of the caves of Kentucky and Indiana, together with several reviews.

Societies and Academies

LEEDS Naturalist's Field Club and Scientific Association, Aug. 5.—Mr. Louis C. Miall read a paper on “The Permian Rocks of the Neighbourhood of Leeds” He first described the base of the Permian System. The carboniferous rocks having been disturbed, thrown into anticlinals and faulted, were greatly denuded, and the Permian rocks were tisen deposited upon the new surface thus produced. The conditions of deposit of the magnesian limestone were then considered. The abundance of mineral salts, exclusive of carbonate of lime, the scantiness of animal life and the dwarfed state of the mollusca, all point to deposition in an inland sea or confined basin similar to the Caspian, Dead Sea, or Great Salt Lake of the present day. In parts of he Triassic period the previous marine surface appears to have become, in part at least, terrestrial or fresh water. At a much later period the Permian rocks, with others of subsequent formation, were denuded extensively, and reduced to the state in which they now occur. The Permian series of the neighbourhood of Leeds were then specially referred to. The Lower New Red Sandstone of South Yorkshire (the Pomfret Rock of Smith) does not appear to be present, at all events in a conspicuous state, in this district. The so-called Lower New Red Sandstone of Plumpton is undoubtedly of carboniferous age. The Upper and Lower Magnesian Limestone are well displayed. Various sections of these rocks at Rigton, East Keswick, Collingham, Whin Moor, and Knaresborough, were described in the paper. Remarks on the colour of the soil produced by underlying Permian rocks on the few fossils which have occurred at Garforth and Cold Hill, near Sherburn, and on the superficial drift, concluded the paper.