Clay Mineralogy of Selected Clays from the English Wealden

Tank, Ronald W.

doi:10.1017/s0016756800057265

Cited by 13 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results of the XRD clay mineralogical analysis show that illite (ca 53%), kaolinite (ca 31%), illite-montmorillonite (10%), vermiculite (ca 5%) and illite-smectite (ca 1%) are the clay minerals present within the two formations ( The degradation of illite to structures similar to vermiculite and montmorillonite in the Ashdown and Wadhurst Clay formations has been previously suggested by Tank (1962). In this present study, illite-montmorillonite is observed in significant quantity as one of the mixedlayer minerals in the lower Ashdown and upper Wadhurst Clay formations.…”

Section: Clay Mineralsmentioning

confidence: 71%

“…Vermiculite is absent at West Hoathly (lower Wadhurst Clay Formation) while illite‐smectite is not present at Rock‐a‐Nore (lower Ashdown Formation). The degradation of illite to structures similar to vermiculite and montmorillonite in the Ashdown and Wadhurst Clay formations has been previously suggested by Tank (). In this present study, illite‐montmorillonite is observed in significant quantity as one of the mixed‐layer minerals in the lower Ashdown and upper Wadhurst Clay formations.…”

Section: Resultsmentioning

confidence: 96%

“…The quantity of kaolinite in the present study demonstrates a warm and humid palaeoclimate, which favoured extensive chemical weathering for the formation of kaolinite. The modification of illite to montmorillonite occurs under advanced weathering patterns (Tank, ). In this present study, illite‐montmorillonite has been recognized as one of the mixed‐layers and its quantity supports severe weathering patterns.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

“…The minerals in the Ashdown and Wadhurst Clay formations have been described (Milner & Bull, 1925;Sweeting, 1925;Allen, 1948) while Cook (1995) explained the dominance of monocrystalline quartz grains in the Wadhurst Clay Formation. The clay minerals within these strata have been documented (Butterworth & Honeyborne, 1952;Tank, 1962;Sladen, 1980Sladen, , 1987Taylor, 1996;Jeans et al, 2001;Jeans, 2006) but previously the focus has been on the general trends. The aim of this study is to use the mineralogy of the Ashdown (Late Berriasian-Early Valanginian) and Wadhurst Clay (Early-Middle Valanginian) formations (Fig.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mineralogy and palaeoenvironments: the Weald Basin (Early Cretaceous), Southeast England

Akinlotan

2017

The Depositional Record

View full text Add to dashboard Cite

Determination of the mineralogy of sedimentary rocks is important in palaeoenvironmental interpretations, especially when outcrop and field data are insufficient or not accessible. The Lower Cretaceous Wealden facies, presented here as a case study, is one such example. Petrographic analysis of this suite of sediments reveals that the arenaceous facies are mainly quartz arenites, quartzose siltstones and lack significant feldspar. The clay minerals are illite, kaolinite, illite-montmorillonite, vermiculite and illite-smectite. The presence of quartz arenites and kaolinite suggests that the rocks were reworked from granitic and/or gneissic rocks. Directly or indirectly, the rocks may have been obtained from a stable craton. The mineral and textural maturity, together with a travel distance of ca 300 km point to matured sources. A warm and humid palaeoclimate in the source areas resulted in extensive weathering.

show abstract

Section: Clay Mineralsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 96%

Section: Interpretation and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mineralogy and palaeoenvironments: the Weald Basin (Early Cretaceous), Southeast England

Akinlotan

2017

The Depositional Record

View full text Add to dashboard Cite

show abstract

“…Mitchell & Taka (1984) have demonstrated that weathered micas fall apart when their K 2 O content gets to 4 5%, so they would never occur as detritus with K 2 O values less than this. Detailed investigations suggest that this young component is an interstratified illite-smectite clay mineral in the Oxford Clay (Weir (Scotchman, 1987a) and a vermiculite in the Wealden (Tank, 1962). Its age is likely to approximate to the chronostratic age of the sample.…”

mentioning

confidence: 92%

Age, origin and climatic signal of English Mesozoic clays based on K/Ar signatures

Jeans¹,

Mitchell²,

Fisher³

et al. 2001

Clay miner.

View full text Add to dashboard Cite

The K/Ar characteristics of 53 clay assemblages (Triassic–Cretaceous), representing the detrital, volcanogenic and arid-facies clay mineral associations, are interpreted in relation to their mineralogy, chronostratic age and geological origins. The K-bearing mineral components of the 1–2 μm, 0.2–1 μm and <0.2 μm fractions of each clay assemblage together display one of two characteristic patterns of K2O and 40Ar values (the K/Ar signature of the assemblage) on a 40Ar/K2O correlation diagram. Interpretation of the K/Ar signatures indicates that: (1) all of these clay assemblages are apparently unaffected by burial diagenetic illitization; (2) the Jurassic and Cretaceous detrital clay assemblages are derived from the reworking of weathered Caledonian metasediments (420 500 Ma) and weathered kaolin-bearing sediments of Upper Devonian/ Carboniferous age; and (3) the role played by palaeoclimate in developing the pattern of clay minerals in the Mesozoic sediments of England is much less significant than previously believed.

show abstract

Multi‐proxy approach to palaeoenvironmental modelling: the English Lower Cretaceous Weald Basin

Akinlotan

2017

Geological Journal

View full text Add to dashboard Cite

Palaeoenvironmental reconstructions of the Wealden (Lower Cretaceous) in southeast England have been previously based mainly on field and fossil data. This study presents new interpretations of multi-proxy data sets such as sandstone petrography, elemental geochemistry and sideritic ironstones, supplemented by outcrop and clay mineralogical data. The dominance of quartz arenites, kaolinite and thorium and the presence of Zr in the sediments suggest that they were sourced mainly from granitic and/or gneissic rocks. Materials from metamorphic sources are secondary in abundance. The mineral and textural maturity of the sediments coupled with inferred short transport distances suggests reworking from older sources. Palaeoclimatic conditions in the source areas were generally warm and humid in nature, which supported an intensive weathering regime. The nature of the sediments suggests they may have been sourced directly or indirectly from a stable craton. The lithology, facies, sedimentary structures, architecture and gamma ray data confirm the freshwater origin of the sediments. Redox-sensitive trace elements such as Mo, U, V and Co suggest anoxic conditions in the basin. The results presented in this paper reinforce the importance of integrating multi-proxy data sets for interpreting the palaeoenvironmental conditions of sedimentary basins: when traditional data sets such as field and fossil data are not readily available or insufficient to enable adequate interpretations, the integration of petrographic, mineralogical and geochemical data sets may prove to be useful in similar palaeoenvironmental studies.

show abstract

Clay Mineralogy of Selected Clays from the English Wealden

Cited by 13 publications

References 9 publications

Mineralogy and palaeoenvironments: the Weald Basin (Early Cretaceous), Southeast England

Mineralogy and palaeoenvironments: the Weald Basin (Early Cretaceous), Southeast England

Age, origin and climatic signal of English Mesozoic clays based on K/Ar signatures

Multi‐proxy approach to palaeoenvironmental modelling: the English Lower Cretaceous Weald Basin

Contact Info

Product

Resources

About