Field meeting on the Lower Greensand and Chalk in the Isle of Wight

Middlemiss, F. A.; Bromley, Richard G.

doi:10.1016/s0016-7878(62)80033-9

Cited by 8 publications

(4 citation statements)

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“…For example, they are known from: (a) the Cenomanian sediments of Dorset and Devon, (b) the Chalk Rock (Holaster planus Zone) of the Chilterns, (c) the Top Rock (Holaster planus Zone) of Cambridgeshire, (d) the chalk of the Micraster cortestudinarium, Marsupites testuainarium, Offaster pilula and Gonioteuthis quadrata zones of the Isle of Wight (Middlemiss and Bromley 1962), (e) the chalk of the Uintacrinus sociale, Marsupites testudinarium, and Offaster pilula zones in the Taplow area, Buckinghamshire (Kennedy and Garrison 1975), and (f) the chalk of the Gonioteuthis quadrata and Belemnitella lanceolata zones of the Norfolk coast (Kennedy and Garrison 1975). Many of these examples have been affected by conspicuous phosphatisation as well as glauconitisation and are also encrusted by organisms, in contrast to those from the Lower Chalk of eastern England.…”

Section: (Ii) Other Examples Of Type-1 Lithificationmentioning

confidence: 99%

Early Submarine Lithification in the Red Chalk and Lower Chalk of Eastern England: A Bacterial Control Model and Its Implications

Jeans

1980

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SUMMARY Early submarine lithifications are common in the Albian and Cenomanian Red Chalk and Lower Chalk of eastern England. They have developed generally in shallow water sediments deposited relatively slowly in the aphotic zone of the Chalk sea. Five varieties of early lithification are described and interpreted in detail. The lithification has occurred during the intrinsic diagenesis of the sediment ranging from very close to the water/sediment interface to some metres below. It has been caused by the precipitation of a ferroan calcite cement (2940–8900 ppm Fe 2+ ) under anaerobic alkaline conditions. The preservation of aragonitic fossils indicates that sources from within the sediment and the external reservoir of sea water supplied the necessary Ca 2+ and CO 3 2− . Indirect evidence suggests that (1) bacterial ammonification and sulphate-reduction have effected the precipitation of the ferroan calcite cement, and (2) porewater temperature, depositional rates, and the content of aragonite and organic matter in the sediment were important factors in controlling the development of early lithification. The importance or the bacterial mechanism as a general lithification process in the aphotic marine environment is discussed.

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Section: (Ii) Other Examples Of Type-1 Lithificationmentioning

confidence: 99%

Early Submarine Lithification in the Red Chalk and Lower Chalk of Eastern England: A Bacterial Control Model and Its Implications

Jeans

1980

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“…) and subsequent workers (e.g. Wright in Arkell, 1947;Wilson et al, 1958;Middlemiss & Bromley, 1962;Casey et al, in preparation).…”

Section: (C) Middle Chalkmentioning

confidence: 97%

“…Phosphatic planus Zone chalks occur in the Lewes area (Strahan, 1896;Jukes-Browne & Hill, 1904). The Micraster cortestudinarium Zone shows spectacular incipient hardgrounds and nodular chalks over the whole area, whilst strikingly mineralized hardgrounds and pebble beds occur in the Isle of Wight (Middlemiss & Bromley, 1962), Dorset and Devon. One of the more obvious features of this zone is the yellowish tinge of many of the nodular horizons.…”

Section: (C) Middle Chalkmentioning

confidence: 99%

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Morphology and genesis of nodular chalks and hardgrounds in the Upper Cretaceous of southern England

1975

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The Upper Cretaceous chalks of southern England are a thick sequence of rhythmically bedded, bioturbated coccolith micrites, deposited in an outer shelf environment in water depths which varied between 50 and 200–300 m. The products of sea floor cementation are widely represented in the sequence, and a series of stages of progressive lithification can be recognized. These began with a pause in sedimentation and the formation of an omission surface, followed by (a) growth of discrete nodules below the sediment‐water interface to form a nodular chalk, erosion of which produced intraformational conglomerates. (b) Further growth and fusion of nodules into continuous or semicontinuous layers: incipient hardgrounds. (c) Scour, which exposed the layer as a true hardground. At this stage, the exposed lithified chalk bottom was subject to boring and encrustation by a variety of organisms, whilst calcium carbonate was frequently replaced by glauconite and phosphate to produce superficial mineralized zones. In many cases, the processes of sedimentation, cementation, exposure and mineralization were repeated several times, producing composite hardgrounds built up of a series of layers of cemented and mineralized chalk, indicating a long and complex diagenetic history. Petrographic study of early cemented chalks indicates lithification was the result of the precipitation of small crystals on and between coccoliths and coccolith fragments. By analogy with known occurrences of early lithification in Recent deeper water carbonates, the cement is believed to have been either high magnesian calcite or aragonite, and more probably the former. The vast scale of operations involved in the cementation process precludes carbonate in expelled pore fluids as the source of cement, whilst quantities of aragonite incorporated in sediment are also inadequate. This, plus the observed association of horizons of early lithification with pauses in sedimentation associated with omission surfaces suggests seawater as a source of cementing materials. Stratigraphic studies indicate that processes of early lithification leading to hardground formation proceeded to completion in intervals to be measured in tens or hundreds of years. Regional studies suggest that early lithification characterized relatively shallow water phases associated with regional regression over the whole of the area, whilst in detail, the distribution of mature mineralized hardground complexes is strongly correlated with sedimentary thinning and condensation over small areas and the buried flanks of massifs. Early cementation in more basinal areas is typically in the form of nodular developments and incipient hardgrounds, whilst day contents in excess of a few percent appear to have inhibited early lithification. The striking rhythmicity of hardgrounds and nodular chalks is no more than a particular expression of the overall rhythmicity of chalk sequences. The stage of early lithification reached in any instance is dependent on sediment type, the time interval represent...

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The geological history of the Isle of Wight: an overview of the ‘diamond in Britain's geological crown’

Hopson

2011

Proceedings of the Geologists' Association

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The geology of the Isle of Wight has attracted both the amateur and professional geologist alike for well over two centuries. It presents a cornucopia of things geological and offers a window into the fascinating story of the geological history and landscape development of southern England, as well as an important teaching resource for all levels of study from primary education through to academic research.This paper provides a geological framework and a summary of the history of research as context for the papers in this issue can be placed. Inevitably, it can only offer a précis of the huge amount of information available, but it is hoped will also give added impetus to further investigation of the literature or, indeed, new research.The island offers a field workshop for topics such as lithostratigraphy, sequence stratigraphy, tectonics and climate change; studies that are becoming ever more international in their influence. There are 15 Sites of Special Scientific Interest designated because of their geological importance and a number of these are internationally significant.After a brief discussion on the concealed geology, this paper concentrates on an outline of the near-surface geology on the coast and inland, and introduces a different view on the structure of the Cretaceous and Palaeogene strata. The enigmatic Quaternary deposits are discussed particularly with reference to the development of the Solent River, human occupation and climate change.

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Field meeting on the Lower Greensand and Chalk in the Isle of Wight

Cited by 8 publications

References 1 publication

Early Submarine Lithification in the Red Chalk and Lower Chalk of Eastern England: A Bacterial Control Model and Its Implications

Early Submarine Lithification in the Red Chalk and Lower Chalk of Eastern England: A Bacterial Control Model and Its Implications

Morphology and genesis of nodular chalks and hardgrounds in the Upper Cretaceous of southern England

The geological history of the Isle of Wight: an overview of the ‘diamond in Britain's geological crown’

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