Harefield Pit
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| TQ049898 | — | Unfavourable Recovering | 1.8 | 2022-03-30 |
Geology & landscape
Mining / Industrial: Quarry · Rock Type: Chalk
Description
Area,1.8 hectares 4.45 ac Description Harefield Pit provides a key section in the London Basin for a sequence through the Upper Chalk, Reading Beds and London Clay. It is also the only known site for calcareous floral remains in the Reading Beds. The site covers part of a disused chalk quarry which has been infilled leaving only the upper faces exposed above ground level. These display a superb Tertiary section including the contact between the Upper Chalk and the Reading Beds, which has here been intensively bored by crustaceans. The faces also show a full section through the Reading Beds, up into mottled fluviatile clays of the Upper Reading Beds. These are overlain by sandy clays with a diverse marine fauna, comprising the Harefield Member of the London Clay, for which this is the stratotype locality. Harefield Pit is additionally of particular interest as the only known source of Charophytes in the Reading Beds. These are important palaeo environmental indicators and have potential for correlation with other coeval localities in Europe. The overlying London Clay Basement Bed has also yielded plant material.