Kingsbury Brickworks

Highlights

Kingsbury Brickworks provides the best exposure of the Halesowen Formation, lying unconformably on alluvial fan deposits of the Etruria Formation (Figure 7.10).

Introduction

This claypit [SP 220 987] on the east side of the Birmingham–Sheffield main railway line, 2.5 km north of Kingsbury, Warwickshire shows an excellent exposure of the Halesowen Formation lying unconformably on the Etruria Formation. The site is briefly mentioned by Bennison and Hardie in Hardie et al. (1971), and a log of the upper part of the sequence is given by Besly (1988, fig. 15.11(c)).

Description

The lower part of the section shows red mudstones, with numerous channels filled with coarse sandstones and conglomerates. This is the alluvial fan association of the Etruria Formation. These beds are overlain by massive, buff sandstones of the Halesowen Formation (Figure 7.11). Besly (1988) interpreted the latter as alluvial channel and over-bank deposits. Palaeocurrent evidence suggests a southerly source for the Halesowen Formation here.

Interpretation

The development of the alluvial fan association in the Etruria Formation here is due to the Western Boundary Fault, which lies only 2 km to the west, and which marks the western margin of the Warwickshire Coalfield. The fault was active during the Westphalian, with a horst lying to the east providing the source for the Etruria Formation sediments. The situation was thus similar to that seen at New Hadley Brickworks, where the alluvial fan association can also be seen.

More significant at this site, however, is the excellent exposure of sandstones of the Halesowen Formation. No biostratigraphical control is available here, but evidence from elsewhere suggests they are late Westphalian D in age (Cleal, 1987). They are thus coeval with the Pennant Formation of the Forest of Dean, and probably with strata of the Oxfordshire Coalfield (Cleal, 1986a). The southern provenance of the Halesowen Formation and its petrological similarity to the Pennant Formation suggests that it is all part of a major belt of sandstones that spread out from the south during the very late Westphalian, perhaps as a response to nappe-loading along the Variscan Front.

Conclusions

Kingsbury Brickworks is the best exposure of rocks known as the Halesowen Formation, which are about 306 million years old. They are probably a lateral equivalent of similar-aged rocks in the Forest of Dean and Oxfordshire coalfields, and represent a belt of river deposits that spread northwards from the growing uplands in southern Britain.

References