They are not laminated and sometimes contain ooids. Ooids can be a distinct characteristic though they are not normally a main component of ironstones. Within ironstones, ooids are made up of iron silicates and/or iron oxides and sometimes occur in alternating laminae. They normally contain fossil debris and sometimes the fossils are partly or entirely replaced by iron minerals.
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The foundry once exploited the ironstones that were easily quarried from the banks of the Powgree Burn. The bridge over the Powgree at Kersland Mill.
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Banded iron formations are distinct from most Phanerozoic ironstones. Ironstones are relatively rare and are thought to have been deposited in marine anoxic events, in which the depositional basin became depleted in free oxygen. They are composed of iron silicates and oxides without appreciable chert but with significant phosphorus content, which is lacking in BIFs. No classification scheme for banded iron formations has gained complete acceptance.
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213x213px Iron formations must be at least 15% iron in composition, just like ironstones and all iron-rich sedimentary rocks. However, iron formations are mainly Precambrian in age which means that they are 4600 to 590 million years old. They are much older than ironstones. They tend to be cherty, though chert can not be used as a way to classify iron formations because it is a common component in many types of rocks.
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Geology of northern Lincolnshire. Near surface iron ore formations in red (NEIMME Transactions, v.24, 1875) It is thought that the iron deposits in Lincolnshire were worked sometime before the 19th and 20th century exploitations – forges at Stowe are mentioned in the Domesday Book, and archaeological evidence has been found of iron working at Scunthorpe. The ironstone in Lincolnshire is thought to have been laid down during the Jurassic period and forms part of a series of ironstones found in eastern England found in the Lias Group of rock strata that also includes ironstone formations making up the Cleveland ironstones and Northamptonshire ironstones; iron deposits in Northern France and Southern Germany may also be from the same period and origin.
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In: Ferrantia Nr. 44, 2005 (Musée national d'histoire naturelle, Luxembourg) p. 22 (pdf, English)Zuzana Vařilová: České Švýcarsko. In: J. Adamovič, V.Cílek (Hrsg.): Železivce české křídové pánve. Ironstones of the Bohemian Cretaceous Basin.
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There is significant contrast from the silty nature of the Middle Lias, Marlstone Rock bed with the Junction Bed of the coast of Dorset and the Midlands ironstones. This contributes significantly to the reconstruction of the geography and the environment of the early Jurassic period.
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The angle between the perfect rhombohedral cleavages is 73° 48', the hardness is 3.5 to 4, and the specific gravity is 2.9 to 3.1. The color is white, grey or reddish to yellowish brown. Ankerite occurs with siderite in metamorphosed ironstones and sedimentary banded iron formations. It also occurs in carbonatites.
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The above classification scheme is the most commonly used and accepted, though sometimes an older system is used which divides iron-rich sedimentary rocks into three categories: bog iron deposits, ironstones, and iron formations. A bog-iron deposit is iron that formed in a bog or swamp through the process of oxidation.
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Chamosite is an iron silicate and it has a birefringence of almost zero. Siderite is an iron carbonate and it has a very high birefringence. The thin sections often reveal marine fauna within oolitic ironstones. In older samples, the ooids may be squished and have hooked tails on either end due to compaction.
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Muswell Hill is a 0.2 hectare geological Site of Special Scientific Interest north-west of Brill in Buckinghamshire. The local planning authorities are Buckinghamshire County Council and Aylesbury Vale District Council. It is listed by the Joint Nature Conservation Committee as a Geological Conservation Review site. This site has sandstones and sandy ironstones.
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Bobdownsite is originally found from Big Fish River, Yukon, Canada (about Latitude 68°28'N, Longitude 136°30'W). Bobdownsite occurs in a vein from an east- west- trending faulted vein. Samples recovered from this exposure are found with Lower Cretaceous bedded ironstones and shales. Bobdownsite is a phosphate mineral with its exposure downstream from phosphate nodule slopes.
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Ironstones consist of 15% iron or more in composition. This is necessary for the rock to even be considered an iron-rich sedimentary rock. Generally, they are from the Phanerozoic which means that they range in age from the present to 540 million years ago. They can contain iron minerals from the following groups: oxides, carbonates, and silicates.
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The cliffs and sandy bays of the coast offer an assortment of seashore habitats. The spectacular scenery where the Cleveland Hills meet the sea has been designated as a Heritage Coast. The cliff at Boulby, at , is the highest point on the east coast of England. Here the Jurassic strata of shales, clays and ironstones are displayed with superb clarity.
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They are ferruginized, highly indurated and compacted. The concentration of Iron in these ironstone units is low, hence, cannot be extracted as ore. Some of the uses of ironstones include for slope stabilization and embankment filling. As coarse aggregate for mixing with mortar and water in order to form strong concrete mixtures, it is also used for erosion control especially in inclined terrain.
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Bobdownsite is the fluorine bearing mineral of the whitlockite group of phosphate minerals whose formula is Ca9(Mg)(PO4)6(PO3F). It is isotypic with whitlockite and was misidentified as such until proper chemical analysis. Whitlockites structure and relationships with other phosphate compounds has been extensively studied. Bobdownsite was first recovered from Big Fish River, Yukon, Canada from a Lower Cretaceous outcrop of bedded ironstones and shales.
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The Group consists of about 1000 m thickness (in the Pwllheli area) of mudstones and siltstones with some basal sandstones together with tuffs and oolitic ironstones laid down during the Arenig and Caradoc epochs of the Ordovician Period. The Nant Ffrancon subgroup alone exceeds 2km thickness in central Snowdonia. The subgroup as itself been classed as both a formation and a group at times.
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To the east are Winter Hill and the West Pennine Moors. Roads lead north to Blackrod, west to Standish, and south to Wigan and Aspull. The Lancaster Canal portion of the Leeds and Liverpool Canal crosses the western part of the township near the River Douglas. Haigh's underlying rocks are the sandstones, shales and ironstones of the Middle Coal Measures of the Lancashire Coalfield and coal and cannel were extensively mined.
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The whole park lies on the Kerri formation, of Tertiary age, which is composed of sandstone, silt stones, kaolinites and grits. Underneath this lies the Gombe formation, of Cretaceous age, composed of sandstones, silt stones, and ironstones. The valleys of the Gaji, Yashi and Yuli Rivers are filled with Alluvium of more recent age. Sandy loans and clayey soils of riverine alluvium occur in the valley of the Gaji Yashi and Yuli Rivers.
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A cross section of the geology of the North York Moors Subsequently, about 30 million years ago, the land was uplifted and tilted towards the south by earth movements. The upper layers of rock were eroded away and the older rocks were exposed in places. Because of the tilt the oldest rocks became exposed in the north. These are the bands of shales and ironstones on the northern scarp of the moors and Cleveland Hills.
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There was a 200 strong riot in the Market Place in 1988, which was quickly brought under control by the police. There have been some concerns over antisocial behaviour and heavier than average litter levels in Princess Diana Park and Hillview Park, and also about fly-tipping in Banbury which affects some streets and footpaths such as on the Ironstones' paths. 17 August 2011 saw only minor scuffles in Banbury as the national riots passed Banbury by.
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It was first described in 1960 by Stuart Olof Agrell in the Laytonville quarry, Mendocino County, California. Zussmanite is named in honor of Jack Zussman (born 1924), Head of the University of Manchester’s Department of Geology and co-author of Rock-Forming Minerals. In the Laytonville quarry, Zussmanite occurs in metamorphosed shales, siliceous ironstones and impure limestones of the Franciscan Formation. It is a location of high pressure and low temperatures where blueschist facies metamorphic rocks occur.
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In 1934, the BGS transferred Hollingworth to the West Midlands section and he began years of fieldwork in Cambridgeshire. When the Second World War began in 1939, Hollingworth joined a team tasked with updating and increasing geological knowledge of the Jurassic ironstones, particularly those in Northamptonshire such as Northampton Sand Formation. These were particularly vital at that time as they served as the UK's chief domestic source of iron ore, which played a crucial part in steel production required by the war effort.
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A similar incident in the Spiceball Park caused heavy damage on 8 February 2007, but did not deter the council from proceeding with a planned £90,000 refurbishment. In 2006, the burning of two spring riders lead to the closure of the Woodgreen Arcade play park. There were some concerns over antisocial behaviour and heavier than average litter levels in Princess Diana Park and Hillview Park, and that fly-tipping in Banbury also affects some streets and footpaths, such as on the Ironstones' paths.
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In their type description they note the etymology for the generic name is in honor of Wesley C. Wehr for his numerous contributions to Tertiary paleobotany of western North America. The specific epithet yakimaensis, is a reference to the type locality in the Yakima Canyon. Pigg and Rothwell noted the similarity between Wessiea and both the modern genus Diplazium and the fossil genus Makotopteris. The second species is known from ironstones of the Campanian age Horseshoe Canyon Formation, Alberta, recovered at the "Fred's site" locality.
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Finedon Top Lodge Quarry, also known as Finedon Gullet (and in the 1960s documented as 'Wellingborough No. 5 Pit') is a 0.9 hectare geological Site of Special Scientific Interest east of Wellingborough in Northamptonshire. It is a Geological Conservation Review site revealing a sequence of middle Jurassic limestones, sandstones and ironstones, and is the type section for a sequence of sedimentary rocks known as the 'Wellingborough Member'. It was created by quarrying for the underlying ironstone for use at Wellingborough and Corby Steelworks; the ore was transported by the gauge Wellingborough Tramway.
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A geological map of the Yorkshire coast. North is orientated to the left top corner of the image. This means that the mouth of the Tees is on the left and the mouth of the Humber on the right As can be seen from the geological map, the Yorkshire Coast is composed of shales, alluviums (sand, clay and gravel), oolites, limestones, mudstone, sandstones, ironstones and chalk. Typically, boulder clay is the section alongside the North Sea in the East Riding of Yorkshire and has been the most prone to coastal erosion.
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In recent years, Rapid Creek, in the northeastern corner of Yukon Territory, has become more popular in the mineralogist community. This is because of the large deposit of phosphate minerals that have been discovered in the area. Texturally, the rocks of Rapid Creek are similar to other Phanerozoic phosphate and iron deposits; they are composed of pellets and granules, detrital quarts grains, skeletal fragments, and siderite mud matrix. Discovered in phosphate-ironstones that crop out near Rapid Creek, penikisite and kulanite occurs in fractures in a sideritic iron-formation.
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The hills are formed from early Carboniferous sedimentary rocks overlying Devonian sandstones and intruded by sills and volcanic plugs during late Carboniferous and Permian times. The lower ground to the north and west is formed from late Devonian rocks of the Glenvale Sandstone Formation traditionally ascribed to the Old Red Sandstone. Overlying this and forming the lower slopes of the scarp are the early Carboniferous sandstones of the Knox Pulpit and the Kinnesswood formations. Next in succession are the Pathhead Formation rocks which include cycles of sandstones, siltstones, mudstones, ironstones and limestone, formerly referred to as the Calciferous Sandstone Measures.
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Evidence of bivalves in life position, Rhizocorallium trace fossils, cross-bedding, episodes of non-deposition and (not least) the oolitic texture all indicate that the ironstones were laid down in shallow water. Fossils are ubiquitous, especially within the ironstone seams, to the extent that the Avicula and Pecten seams are named after their most abundant faunal inclusions. NOTE: The only surviving extensive outcrop of the Main Seam occurs in woodland north of Skelton (close to NZ 6554 1997) at around 50m O.D above Skelton Beck achieving a thickness of around 2.4m (8 feet). It is underlain by the Black Hard, and three beds making up the Pecten Seam.
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The Fossil Grove is on a by floor of an old quarry, and belongs to the same geological time period as several other groups of Lepidodendron fossils found northwest of Glasgow. The shales and sandstones exposed around the fossils belong to the Limestone Coal Formation of the Clackmannan Group, with the shale containing imprints of various plant remains. The strata were deposited approximately 325 million years ago when the trees were still alive, and the strata are now folded and cut by many faults and slant downwards to the northeast. Beds of coal and some ironstones can be found in the northern and eastern parts of the Grove.
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Formerly known as the 'Great Oolite Limestone', the Blisworth Limestone is a widespread series of limestone beds that run the full length of Northamptonshire. They were laid down in a fully marine saltwater sea at the end of the Bathonian Age, at a time when the earlier lagoons were once more below sea level over a wide area, so that a wide area, including the largely flat surface of the earlier Cranford rhythm received a deposition that was at times mud and other outwash from the nearby landmass, and at other times accumulations of shells and other marine detritus which also received substantial precipitation of limestone held within the seawater. The beds are named after a village with extensive quarries south of Northampton, where it was studied at the end of the 18th century whilst the Blisworth Tunnel was being built for the Grand Union Canal. The Limestone has been widely used across Northamptonshire for building stone, and takes a wide variety of colours in cream and beige - rather than the dark browns of the ironstones.
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