The geological significance of a negative gravity anomaly in the South Wales Coalfield
β Scribed by M. D. Thomas; M. Brooks
- Publisher
- John Wiley and Sons
- Year
- 1973
- Tongue
- English
- Weight
- 957 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0072-1050
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β¦ Synopsis
Abstract
Three gravity traverses across the eastern half of the South Wales Coalfield indicate a local, elongate, negative Bouguer anomaly of a few milligals amplitude bordering the southern rim. The anomaly has a maximum amplitude of 4 mgal near Maesteg and attenuates eastward, dying out in the vicinity of the East Crop. Two possible geological causes of the anomaly are examined, namely a local thick sequence of normal Upper Carboniferous strata and a discrete, lowβdensity body of Carboniferous age with no apparent surface expression. The former, uncontroversial explanation requires rock densities at variance with measured values. In the case of the hypothetical low density body which can explain the anomaly, a variety of possible ages and configurations are discussed.
π SIMILAR VOLUMES
Small-scale thrust faults are described from the North Crop of the South Wales Coalfield in strata of Avonian age. Two main sets occur which strike at east-west and north-south respectively. and show apparent stratigraphic zonation. It is suggested that the sets were initiated during the early stage