Cleveland Ironstone Research Articles

Natural fractures in a United Kingdom shale reservoir analog, Cleveland Basin, northeast England

Faults and fractures within the well-exposed Lower Jurassic Cleveland Ironstone and Whitby Mudstone Formations may provide insights into the tectonic history of gas-prospective, Mississippian shale in northern England. Subvertical opening mode fractures occur throughout the Cleveland Basin. Bed-parallel fractures, some of which contain blocky calcite fills, occur preferentially within well-bedded, clay-rich mudstones of the Cleveland Ironstone and Whitby Mudstone Formations at Jet Wyke and Port Mulgrave. Subvertical fractures display abutting or curving-parallel relationships with under- and overlying bed-parallel fractures. Together, these observations suggest that bed-parallel fractures, at times, acted as free surfaces. Some bed-parallel fractures curve toward and branch from calcite-filled fault slip surfaces, indicating that bed-parallel fracturing and normal faulting were synchronous, occurring within a regional stress field with vertical maximum principal stress. This apparent paradox can be explained by normal compaction, followed by cementation and coupling between pore pressure and minimum horizontal stress driven by poroelastic deformation or incipient slip along critically stressed normal faults, causing elevation of horizontal stress in excess of the vertical stress within clay-rich units. Propagation of bed-parallel fractures was enhanced by dilatational strains adjacent to normal fault planes. Bed-parallel fractures have not been observed within more -rich units at the top of the Whitby Mudstone Formation at Whitby East Cliff, or within well-bedded, clay-rich shale at Saltwick Nab. This observation is consistent with the lack of normal faulting at Saltwick Nab, and the Whitby Mudstone Formation having been drained by structural and/or stratigraphical juxtaposition against permeable Middle Jurassic sandstones at both these localities.

Wave-enhanced sediment-gravity flows and mud dispersal across continental shelves: Reappraising sediment transport processes operating in ancient mudstone successions

Recent studies of marine shelf sediment dispersal show that wave-enhanced sediment-gravity flows are widespread phenomena and can transport large volumes of fluid mud rapidly across low-gradient shelves. Flow evolution is controlled by sediment supply, seabed gradient, and spatial distribution of wave energy at the seabed. Using existing flow models, we predict that such flows in mud-dominated sediments will develop a three-part microstratigraphy produced by changing flow conditions, beginning with wave-induced turbulent resuspension, then development of a wave-enhanced sediment-gravity flow, prior to lutocline collapse and suspension settling. Petrographic examination of modern flow deposits collected from the Eel Shelf reveals that resultant beds possess a microstratigraphy consistent with our hypothesis: a silt-rich basal subunit with curved ripple laminae, abruptly overlain by a subunit composed of continuous intercalated silt/clay laminae, and an upper clay-rich drape. Analyses of beds from ancient mud-rich outer-shelf and basinal successions (Cleveland Ironstone, Jurassic, UK, and Mowry Shale, Cretaceous, United States) show that they too contain beds with this three-part organization, suggesting that such flows were active in these ancient settings too. Recognition of these microstructures in these ancient mud-dominated successions demonstrates that sediment in these settings was commonly reworked and transported advectively downslope by high-energy events, contrasting with previous interpretations of these units that deposition was dominated by quiescent suspension settling. Identification of these recognition criteria now allows the products of this newly recognized sediment dispersal mechanism to be identified in other shale-dominated successions.

Jurassic sedimentation in the Cleveland Basin: a review

Jurassic sedimentation in the Cleveland Basin: a review

Clay mineralogy of the Jurassic strata of the British Isles

AbstractThe nature and origin of the clay mineralogy of the Jurassic strata of the British Isles are described and discussed within their lithological and biostratigraphical framework using published and unpublished sources as well as 1800 new clay mineral analyses. Regional clay mineral variation is described systematically for the following formations or groups:England and Wales(i)Hettangian-Toarcian strata (Lias Group): Redcar Mudstone Fm.; Staithes Sandstone Fm.; Cleveland Ironstone Fm.; Whitby Mudstone Fm.; Scunthorpe Mudstone Fm.; Blue Lias Fm.; Charmouth Mudstone Fm.; Marlstone Rock Fm.; Dyrham Fm.; Beacon Limestone Fm.; Bridport Sand Fm.(ii)Aalenian-Bajocian (Inferior Oolite Group): Dogger Fm.; Saltwick Fm.; Eller Beck Fm.; Cloughton Fm.; Scarborough Fm.; Scalby Fm. (in part); Northampton Sand Fm.; Grantham Fm.; Lincolnshire Limestone Fm.; Rutland Fm. (in part); Inferior Oolite of southern England.(iii)Bathonian (Great Oolite Group): Scalby Fm. (in part); Rutland Fm. (in part); Blisworth Limestone Fm.; Great Oolite Group of southern England; Forest Marble Fm.; Cornbrash Fm. (in part).(iv)Callovian-Oxfordian: Cornbrash Fm. (in part); Kellaways Fm.; Oxford Clay Fm.; Corallian Beds and West Walton Beds; Ampthill Clay Fm.(v)Kimmeridgian-Tithonian: Kimmeridge Clay Fm.; Portland Sandstone Fm.; Portland Limestone Fm.; Lulworth Fm.; Spilsby Sandstone Fm. (in part). Scotland(vi)Hettangian-Toarcian: Broadfoot Beds, Dunrobin Bay Fm. Aalenian-Portlandian: Great Estuarine Group (Dunkulm, Kilmaluag and Studiburgh Fm.s); Staffin Shale Fm.; Brora Coal Fm.; Brora Argillaceous Fm.; Balintore Fm.; Helmsdale Boulder Beds (Kimmeridge Clay Fm.).Dominating the Jurassic successions are the great marine mudstone formations — the Lias Group, Oxford Clay, Ampthill Clay and Kimmeridge Clay. These are typically characterized by a detrital clay mineral assemblage of mica, kaolin and poorly defined mixed-layer smectite-mica-vermiculite minerals with traces of chlorite. Detailed evidence suggests that this assemblage is derived ultimately from weathered Palaeozoic sediments and metasediments either directly or by being recycled from earlier Mesozoic sediments. A potassium-bearing clay is a persistent component and formed at approximately the same time as the deposition of the host sediment, either in coeval soils or during very early diagenesis.At three periods during the deposition of the Jurassic (Bajocian-Bathonian, Oxfordian and late Kimmeridgian-Tithonian), the detrital clay assemblage was completely or partially replaced by authigenic clay mineral assemblages rich in kaolin, berthierine, glauconite or smectite minerals. Associated with these changes are major changes in the lithofacies, with the incoming of non-marine and proximal marine strata. The authigenic clay assemblages rich in kaolin and berthierine are generally restricted to the non-marine and very proximal marine beds, those rich in glauconite or smectite are typical of the marine lithofacies. Clay mineral assemblages containing vermiculite and mixed-layer vermiculite-chlorite sometimes occur in the non-marine and proximal marine facies. The causes of these major changes in lithofacies and clay mineralogy are discussed, and present evidence favours an important volcanogenic influence and not climatic control. It is suggested that the Bajocian-Bathonian, Oxfordian and Late Kimmeridgian-Tithonian were periods of enhanced volcanic activity, with centres probably located in the North Sea and linked to regional tectonic changes which caused major modifications of the palaeogeography of the British Isles. The most important of these changes was the development of the central North Sea Rift Dome during the Bajocian and Bathonian. Volcanic ash was widespread in both the non-marine and marine environments and its argillization under different conditions provided the wide range of authigenic clay mineral assemblages.Metre-scale clay mineral cyclicity is widespread in most of the Jurassic mudstone formations that have been examined in sufficient detail. The cyclicity is defined by systematic variations in the mica/ collapsible minerals (mixed-layer smectite-mica-vermiculite) ratio. This variation is unrelated to changes in lithology and its possible origins are discussed in detail using data from the Kimmeridge Clay provided by Reading University's contribution to the Rapid Global Geological Events (RGGE) Project.

The importance of pyritic roof strata in aquatic pollutant release from abandoned mines in a major, oolitic, berthierine-chamosite-siderite iron ore field, Cleveland, UK

Abstract The Cleveland Ironstone Field (NE England) is a major sedimentary iron orefield in which the principal ore minerals are iron silicates (berthierine, chamosite) and carbonates (siderite). The siderite in this area is known to be rich in Mg and Mn in solid solution with Fe. Although this ore assemblage would not normally be expected to give rise to acid mine drainage phenomena, a number of discrete ferruginous mine water discharges (totalling some 6.5 million litres (Ml) day −1 ) have been identified flowing from abandoned underground mine workings and old spoil heaps in the ore field. Some of these discharges are extremely acidic (pH ≥ 3.3), with total Fe reaching 1220 mg l −1 . At the point of first emergence to the surface, most of the discharges are so highly charged with dissolved CO 2 that they effervesce. Upon degassing, one of the discharges precipitates a ferroan calcite deposit, which is most unusual as a mine water discharge precipitate. All the other discharges precipitate more usual ferrihydrite and goethite ‘ochres’. The geochemistry of these waters supports the view that oxidation of pyrite in the roof strata initiates dissolution of siderite in the old workings, releasing CO 2 , Fe and Mg to solution. This chain of reactions results in these waters having SO 2− 4 as their major anion (from pyrite weathering) with Mg as the major cation (except where Fe exceeds Mg in concentration). Two of the near-coastal discharges have Na as the major cation, and elevated Cl concentrations, suggesting a sea-water component. However, SO 4 /Cl ratios suggest that sea water can account for no more than 20% of these waters. Most of the Cleveland mine waters have significant environmental impacts, ranging from ecological damage to receiving water courses to flooding problems caused by the clogging of surface sewers with mine water precipitates. A range of remedial measures are proposed.

Early diagenetic pyrite morphology in a mudstone-dominated succession: the Lower Jurassic Cleveland Ironstone Formation, eastern England

Abstract Diagenetic pyrite in the mudstones and ironstones of the Lower Jurassic Cleveland Ironstone Formation of eastern England exhibits two distinct morphologies: framboidal pyrite, commonly associated with organic matter, and euhedral pyrite, associated with detrital clay pellets. These two morphologies are mutually exclusive in occurrence. Framboidal pyrite is present in clay-rich mudstones, ooidal ironstones, apatite-rich units and some silt-rich mudstones. Euhedral pyrite is present in silt-rich and sand-rich mudstones. δ34S isotopic analysis of six samples of pyrite suggests that both types of pyrite morphology precipitated during early diagenesis from porewaters with open access to overlying sea-water, although both probably acted as sites for continued pyrite precipitation during burial. It is proposed that framboidal pyrite precipitated from iron-dominated porewaters at sites of sulfide supply (i.e. in the region of organic matter as a result of bacterial sulfate reduction) where, locally, sulfide production rates were high enough for porewaters to reach supersaturation with respect to FeS. Euhedral pyrite also precipitated from iron-dominated porewaters, but sulfide production rates from organic matter was such that FeS saturation was not reached at the sites of sulfide production. Instead, euhedral pyrite was precipitated directly from porewater when FeS2 saturation was reached. The control over pyrite morphology was probably the amount and reactivity of the organic matter within the deposited sediments. The sand-rich mudstones contained less reactive organic matter due to clastic dilution and deposition in shallower environments with O2-rich bottom waters. The ironstones and apatite-rich units were deposited under very low sedimentation rates, and as a result organic matter contents were very low and iron reduction dominated early diagenesis, which inhibited sulfate-reduction. The presence of minor framboidal pyrite within these units, however, suggests that sulfide reduction took place in micro-environments during early diagenesis.

The Seasonal Climate of the Early-Middle Jurassic, Cleveland Basin, England

Diverse aspects of the fossil floras of the Early to Middle Jurassic (Cleveland Ironstone and Dogger Formations and Ravenscar Group; Pliensbachian-Bathonian stages) of North Yorkshire, England, have been investigated in order to better define the prevailing Early-Middle Jurassic paleoclimate. Growth rings in fossil woods have been characterized in terms of their 'mean sensitivity'; overall woods are 'complacent' and grew well within the bounds of their climatic tolerance, but woods from the oldest and, particularly, youngest parts of the succession analyzed (the Dogger and Scalby Formations, respectively) show greater interseasonal variation in growth. Intraseasonal variability in growth is indicated by the ubiquitous presence of false rings. Further evidence of seasonality from the fossil floras is the occurrence of leaf beds (ginkgophytes and Nilssoniopteris) interpreted as resulting from the deposition of leaves shed from deciduous plants during flood seasons. Charcoal is ubiquitous throughout the succession and wood samples often show 'checking' of cell walls as a microscopic feature. These observations, combined with a consideration of the depositional and diagenetic history of the host sedimentary rocks, indicate the predominance of a winter-wet seasonal paleoclimate, which was characterized by greater aridity in the late Bajocian-Bathonian relative to the Pliensbachianmid Bajocian. The increasing aridity towards the close of this interval may have been partly a function of regional withdrawal of the extensive seaway that characterized the area for most of the preceding Early Jurassic, but also may have been an early manifestation of the continent-wide arid phase that affected Eurasia during the Late Jurassic.

Discussion on a sequence-stratigraphic interpretation of a mudstone-dorninated succession: the Lower Jurassic Cleveland Ironstone Formation, UK

S. P. Hesselbo writes: Macquaker & Taylor (1996) have provided a well-illustrated account of sediment micro fabrics in the Cleveland Ironstone Formation, and have clarified the occurrence of phosphate within part of the succession at Staithes. It may be useful, however, to discuss some of their broader conclusions, particularly those relating to sequence stratigraphy. A principal theme of the paper is that subtle trends in grain-size distribution, revealed though microfacies analysis, leads to a re-assessment of the sequence stratigraphy of the Cleveland Ironstone in particular, and ‘mudstone-dominated’ successions in general. It should be noted that both the number of samples (37), and the size of the samples (?< 1 cm 2 ) are small. Trends must therefore be highly susceptible to bias resulting from small-scale sediment inhomogeneity, which is undoubtedly present in the succession (e.g. as described for this interval by Greensmith et al. 1980 ). The authors' results are novel in that they document: (a) a fining-upward trend over c elm above the Avicula Seam, and (b) three separate coarsening-upward cycles between the Avicula Seam and the Raisdale Seam. The problem is that these features rely on three key samples (ST5, ST14, and ST19), without any of which the grain-size arguments are significantly weakened. Because the grain-size plots are based on visual estimates, the 5% change in silt content between ST18 and ST19 is not very convincing, especially in view of the theoretical problems of deriving a 3D quantity (grain-size distribution) from a 2D data set (polished section) Furthermore, the plot in

A sequence-stratigraphic interpretation of a mudstone-dominated succession: the Lower Jurassic Cleveland Ironstone Formation, UK

Microfacies analysis (using optical and backscattered electron imagery) has been undertaken on 37 samples from the Cleveland Ironstone Formation, Staithes, Yorkshire, UK. Four lithofacies were encountered: clay-rich mudstones, silt-rich mudstones, sand-rich mudstones and concretionary carbonates (two types: berthierine/siderite-rich ironstones and apatite-rich concretionary horizons). Successive units were found to stack systematically into upward-coarsening units on a small (0.1–1.0 m) scale. Upward-coarsening and upward fining packages were also found on a larger (1.0–3.0 m) scale. The small-scale upward-coarsening units are interpreted to be parasequences; while the large scale upward-fining and upward-coarsening packages are interpreted to be retrogradational and progradational parasequence sets respectively. The ironstones occur at the level where the stacking patterns change from being overall progradational to retrogradational, while the apatite-rich concretionary units occur at the level where the stacking patterns change from being retrogradational to progradational. The concretionary carbonates are interpreted to have formed close to/at major stratal surfaces. The ironstones are interpreted to be either the correlative equivalent of sequence boundaries or part/all, of the forced regressive system tract; while the apatite-rich units are interpreted to have precipitated close to/at maximum flooding surfaces (condensed sections) and/or major transgressive surfaces.

The origin of the Lower Jurassic Cleveland Ironstone Formation of North-East England: evidence from portable gamma-ray spectrometry

Summary The distribution of K, U and Th in the Cleveland Ironstone Formation, measured by gamma-ray spectrometry, is found to be useful in investigating the origin of oolitic ironstones. The oolitic ironstone seams are enriched in Th and depleted in K relative to the interbedded mudstones which show a close correlation between Th and K. The enrichment of Th in the ironstone seams represents a primary depositional rather than a diagenetic process, and the Th-enriched material must have been transported to the site of ironstone deposition from elsewhere. The values of Th (20–45 ppm) and the Th/K ratios (20–100) recorded in the ironstone seams are consistent with the original Th-enriched material being kaolinitic/bauxitic clay from a lateritic weathering source.

Lithostratigraphy of the Staithes Sandstone and Cleveland Ironstone formations (Lower Jurassic) of north-east Yorkshire

SUMMARY The lithostratigraphy of the Staithes Sandstone and Cleveland Ironstone formations in North Yorkshire and Cleveland is reviewed and redefined; two new subdivisions, the Penny Nab and Kettleness members, are proposed for the Cleveland Ironstone Formation. Both formations and members are recognisable throughout the Cleveland Basin, but only the Kettleness Member continues southwards over the Market Weighton High, where it undergoes lateral facies change into the Marlstone Rock Bed. The latter, together with a finer grained representative of the Staithes Sandstone Formation, can be tentatively identified in the southern North Sea area.

Coarsening-upwards cycles in the uppermost Staithes and Cleveland Ironstone Formations (Lower Jurassic) of the Yorkshire coast, England

Coarsening-upwards cycles in the uppermost Staithes and Cleveland Ironstone Formations (Lower Jurassic) of the Yorkshire coast, England

Depositional Environment of the Cleveland Ironstone Series

DR. HALLAM has recently restated some of the problems involved in an understanding of the oolitic ironstones of the British Lias, and has emphasized the importance of a close examination of their facies relationships1.

Bessemer Gold Medal: Award to Mr. Harold Wright

MR. HAROLD WRIGHT, chief metallurgist to Dorman Long and Co., Ltd., Middlesbrough, has been awarded the Bessemer Gold Medal by the Iron and Steel Institute in recognition of his "valuable contributions made over many years to improve the technique of iron and steel manufacture". The Medal, which is the highest award conferred by the Institute, will be presented to Mr. Wright by the president, Mr. Arthur Dorman, at the annual meeting of the Iron and Steel Institute in London on May 9. Mr. Harold Wright has been a member of the Institute since 1902 and has served on its Council; he is a past president of the Cleveland Scientific and Technical Institution and of the Cleveland Institution of Engineers. He started work at the North Eastern Steel Works. While with Sir Bernard Samuelson, Mr. Wright took an active part in the supply of molten basic iron to Dorman Long's Britannia Works when the latter firm introduced the hot metal process forty years ago. While in charge of the Newport coke ovens, Mr. Wright promoted the use of coke oven gas for town purposes. He first made the suggestion in 1902, but it was 1913 when the supply was first established. Mr. Harold Wright also possesses considerable geological knowledge, and has done a great deal of exploration work in connexion with the Cleveland ironstone deposits. He was also responsible for the introduction into local blast furnace practice of the use of rich foreign ores in the Cleveland burden. Mr. Harold Wright was appointed chief metallurgist to Dorman Long and Co., Ltd., in 1918. Last December the Company inaugurated a triennial Harold Wright Lecture to be given before the Cleveland Scientific and Technical Institution in recognition of his long and valuable service.

THE PETROGRAPHY OF JURASSIC SEDIMENTS IN YORKSHIRE

I. Introduction. Although the Jurassic rocks of Yorkshire are more sandy than those of other parts of England, and therefore more easily studied by methods for the separation and microscopic examination of heavy minerals, no comprehensive account of this aspect of Jurassic Geology has been attempted. A few papers have, however, dealt with the petrography of certain Yorkshire Jurassic deposits. Mr. C. R. Lindsay (1905)1 recorded from the Cleveland Ironstone the minerals brookite, anatase, rutile, tourmaline and pyrite, to which Dr. J. E. Stead (1910) added sphalerite (zinc blende). Professor P. G. H. Boswell (1918) has described glass sands from the Upper Estuarine Series and Kellaways Rock, recording a large number of minerals, and has recorded (1926) ceylonite (pleonaste) and monazite in the Callovian and chloritoid in the Upper Estuarine Series, while noting “the impoverished character and frequent small size of the mineral assemblages of the various Jurassic strata of Yorkshire.” Professor Boswell has also recorded purple zircon in the Estuarine Series and Callovian of Yorkshire (1927). More recently Dr. R. H. Rastall (1932) has described heavy residues from the Lower Estuarine Series in Eskdale, commenting on the small number of mineral species present and on the abundance of the titaniferous minerals, rutile, anatase and brookite, while Dr. F. C. Phillips (1932) has given an account of the brookite which Dr. Rastall obtained. The present account is based upon an examination of more than 300 samples, ranging from the Lower Lias to the Kimeridge Clay and collected throughout the area ...

Mr. Joseph Lucas

MR. JOSEPH LUCAS, who died on April 20 last at the age of seventy-nine years, was educated at Westminster School and in 1867 joined the Geological Survey of Great Britain. During his nine years in the service he was employed in mapping the Carboniferous rocks in the West Riding of Yorkshire, and, later, the area in north-east Yorkshire, within which the Cleveland ironstone occurs. While in the West Riding he was much impressed with the great amount of water yielded by the Lower Carboniferous sandstones, and this probably led to his taking up the study of water supply and the profession of water engineer on his retirement from the Geological Survey.

Note on the occurrence of Brookite in the Cleveland ironstone

The references to the occurrence of the titanium dioxide minerals as rock constituents have been so recently summarized in the ‘Mineralogical Magazine, that it is unnecessary to repeat them, except to refer again to Mr. J. J. H. Teall's record of anatase in the Cleveland ironstone.Wishing to procure some of these crystals, a pound of ore from the Main Seam at Upleatham mines was treated by the usual processes of solution, washing by decantation, and separation by heavy solution. The residue obtained was equal to 0.16 per cent. of the material taken, and consisted mainly of anatase, mostly in sharply developed pyramidal crystals, with some pyrites in nodular concretions, possibly in replacement of some of the oolitic grains, together with other minerals of derived origin, among which futile and tourmaline were the most prominent.