The role of fluids in the evolution of the South Wales coalfield foreland basin

R. A. Gayer, Julia Cole, K. Frodsham, A. J. Hartley, B. Hillier, M. Miliorizos, S. C. White

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The South Wales coalfield developed as a Silesian flexural basin in response to Variscan tectonic loading in the Bristol Channel and SW England. Subsequent northward propagation of thrust deformation into the coal basin is recorded in the later stages of the foreland basin evolution. The temperatures required for the development of the anthracite field, in the NW of the coalfield, are unlikely to have developed by burial within a normal continental geotherm. It is argued that the style of thrust deformation, in which several thrust detachments parallel to coal seams moved simultaneously, producing a progressive easy-slip thrust (PEST) style, probably required fluid over-pressuring in the coal seams for its development. Preliminary study of mineralisation, developed in pre- and syn-thrusting fractures within the coal, reveals: pyrophyllite, stable at temperatures between 225-275°C in the presence of methane; and the hydrothermal minerals, harmotome, galena and sphalerite. Together, these minerals suggest the presence of hot fluids passing through the coal, resulting in a perturbation of the geotherm to generate anthracite, and over-pressuring of the coal seams to trigger PEST deformation. It is suggested that these fluids may have originated within the Variscan tectonic wedge to the south, and may have been driven by a combination of gravity flow and thrust load expulsion forwards and upwards into the coal basin.

Original languageEnglish (US)
Pages (from-to)380-384
Number of pages5
JournalGeoscience in South-West England
Volume7
Issue number4
StatePublished - 1991
Externally publishedYes

Fingerprint

foreland basin
thrust
fluid
coal seam
coal
anthracite
Hercynian orogeny
tectonic wedge
basin
pyrophyllite
Silesian
gravity flow
mineral
galena
sphalerite
basin evolution
methane
temperature
perturbation
mineralization

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)

Cite this

Gayer, R. A., Cole, J., Frodsham, K., Hartley, A. J., Hillier, B., Miliorizos, M., & White, S. C. (1991). The role of fluids in the evolution of the South Wales coalfield foreland basin. Geoscience in South-West England, 7(4), 380-384.

The role of fluids in the evolution of the South Wales coalfield foreland basin. / Gayer, R. A.; Cole, Julia; Frodsham, K.; Hartley, A. J.; Hillier, B.; Miliorizos, M.; White, S. C.

In: Geoscience in South-West England, Vol. 7, No. 4, 1991, p. 380-384.

Research output: Contribution to journalArticle

Gayer, RA, Cole, J, Frodsham, K, Hartley, AJ, Hillier, B, Miliorizos, M & White, SC 1991, 'The role of fluids in the evolution of the South Wales coalfield foreland basin', Geoscience in South-West England, vol. 7, no. 4, pp. 380-384.
Gayer RA, Cole J, Frodsham K, Hartley AJ, Hillier B, Miliorizos M et al. The role of fluids in the evolution of the South Wales coalfield foreland basin. Geoscience in South-West England. 1991;7(4):380-384.
Gayer, R. A. ; Cole, Julia ; Frodsham, K. ; Hartley, A. J. ; Hillier, B. ; Miliorizos, M. ; White, S. C. / The role of fluids in the evolution of the South Wales coalfield foreland basin. In: Geoscience in South-West England. 1991 ; Vol. 7, No. 4. pp. 380-384.
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