Fabric deformation induced in Cretaceous chalks by tectonic stresses

Mimran, Y.

doi:10.1016/0040-1951(75)90097-9

Cited by 39 publications

(8 citation statements)

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“…The role of the increasing deformation on the hardness and composition of the Middle (Turonian) and Upper ('Senonian') Chalk associated with post-Cretaceous steep, asymmetrical east-west folding in southern England (Surrey; Isle of Wight; Dorset) and Yorkshire has been investigated by Mimran (1975Mimran ( , 1977Mimran ( , 1978, making comparison to his own findings (ideas) on the unfolded chalk of Northern Ireland (Mimran 1978) which differ significantly from those of Wolfe (1968) and Scholle (1974). Mimran (1977Mimran ( , 1978 modelled the effects of increasing deformation using measurements of acid insoluble residue, bulk specific gravity (intact dry density), concentration and distortion of calcispheres (assumed to be originally spherical in form), values of various elements (Sr, Mg, Ti, Ba), and stable isotopes (δ 18 O, δ 13 C) in bulk chalk calcite, and microfabric analysis.…”

Section: Previous Researchmentioning

confidence: 98%

Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, Uk: Direct evidence from calcite-filled vugs in brachiopods

Hu¹,

Jeans²,

Dickson³

2012

Acta Geologica Polonica

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The Upper Cretaceous Chalk of the British Isles is famous for its whiteness, thickness (800 m) and the magnificent cliffs it forms on the coast of Yorkshire, Kent, Sussex, Isle of Wight and Dorset. Compositionally its sediments are dominated by the low-Mg calcite skeletons of the Coccolithophoridae, usually admixed with minor but varying amounts of foraminifera, bivalves and the calcareous skeletal fragments of other marine invertebrates, as well as the siliceous skeletons of sponges and radiolaria. Traces of continentally de-

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Section: Previous Researchmentioning

confidence: 98%

Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, Uk: Direct evidence from calcite-filled vugs in brachiopods

Hu¹,

Jeans²,

Dickson³

2012

Acta Geologica Polonica

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“…The fundamental principle behind the present study is that the chalk in each of the areas investigated exists in a variety of stages of alteration induced by tectonic stresses (Mimran, 1975a). Emphasis has been placed on the relation of certain petrographic features of the chalks to tectonic features in the rocks.…”

Section: The Present Studymentioning

confidence: 99%

Chalk deformation and large‐scale migration of calcium carbonate

Mimran

1977

Sedimentology

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Sixty Upper Cretaceous chalk exposures were examined and sampled in Dorset, the Isle of Wight and Guildford, South England, in order to investigate the effects of tectonic deformation on the chalk fabric. Light and scanning‐electron microscopes were used extensively, and chemical, mineralogical and isotopic analyses ware carried out. Two types of fabric modification were distinguished. The first type involves more than 90% volume loss by mechanical compaction at the early stages of deformation followed by dissolution and removal of calcium carbonate in the advanced stages of deformation. Chalks which have undergone this type of fabric modification are dense and consist of well rounded 0.5–3 μ calcite crystals with well developed pressure‐solution contacts. These chalks contain a high proportion of calcispheres (many of which are plastically deformed) but very few well preserved planktonic foraminifera and coccoliths. They are relatively enriched in insoluble constituents and depleted in strontium. The second type of fabric modification involves introduction of calcium carbonate into the pore spaces. Chalks which have undergone this type of modification are dense and contain a high proportion of 3–5 μ polygonal interlocking calcite crystals. Fossils are virtually never deformed, and delicate foraminifera and coccoliths are well preserved. Insoluble constituents similar to those found in the unmodified chalks occur in low concentrations. Removal of calcium carbonate at crystal contacts has taken place in chalks which have been subjected to high effective tectonic stresses and at crystal peripheries in chalks which have been subjected to high pore fluid pressure. Dissolution at crystal peripheries is responsible for the extensive calcium carbonate losses, and it is termed herein ‘confining pressure solution’. Introduction of calcium carbonate occurs in rocks which were under low tectonic stresses. During deformation calcium carbonate migrates from chalks under high stresses towards those under tow stresses, while some goes into solution in sea water. Well developed joints and high pore fluid pressure might increase the rate of calcium carbonate removal by three orders of magnitude. Petrographic and isotopic data suggest‐that all fabric modifications studied took place in meteoric water.

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“…The dissolution of grain under lithotomic stress is an important criterion for the recognition of rock deformation (Mimran, 1975;Mimran, 1977, Alvarez et al, 1976. The pressure solution in the rocks was categorized into the intergranular and stylolitization Fig.…”

Section: Discussionmentioning

confidence: 99%

Diagenesis of Miocene Sandstone in the District Sudunhoti and Poonch, Azad Jammu and Kashmir, Pakistan

Yasin¹

2017

Pak. j. geol.

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The petrographic analysis of Miocene sandstone at latitude 33° 45' 00" N to 33° 51' 30" N and Longitude 73° 35' 36" E to 73° 45' 00" E in the Himalayan fold and thrust belt was based on field observations and study of representative samples. At least 30 rock samples dislodged from outcrops for thin section preparations were soaked in blue epoxy resin before thin section grinding, then etched and stained using alizarin-red and potassium ferrocyanide for carbonate identification. The stratigraphic sections in the area were measured by tape-compass-clinometer method. Petrographic and textural data revealed that the quartz, feldspar, rock fragments, accessories, matrix and cement form the bulk composition of the rocks. The Miocene sandstones are lithic arenites and lithic greywackes. Further interpretation revealed the fracturing, flexure grain deformations, dissolutions, stylolitization, clay minerals anthogenesis, calcite and silica cementation during the diagenetic history of rocks.

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Fabric deformation induced in Cretaceous chalks by tectonic stresses

Cited by 39 publications

References 2 publications

Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, Uk: Direct evidence from calcite-filled vugs in brachiopods

Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, Uk: Direct evidence from calcite-filled vugs in brachiopods

Chalk deformation and large‐scale migration of calcium carbonate

Diagenesis of Miocene Sandstone in the District Sudunhoti and Poonch, Azad Jammu and Kashmir, Pakistan

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