Geology Site Account

Site name: Hall's Quarry SSSI

Grid reference: TL 519 280

Brief description of site:

Hall's Quarry SSSI (also known as Ugley Park Quarry) has exposures of glacial gravels and boulder clay (till) related to the Anglian glaciation, 450,000 years ago, the coldest period of the Ice Age when an ice sheet reached as far as south Essex. The Site of Special Scientific Interest (SSSI) relates to two representative sections in the northern part of the pit.

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Details

Halls Quarry has exposures of glacial gravels, silts and boulder clay relating to the Anglian glaciation. It is important for demonstrating the stratigraphical relationship of the glacial deposits and meltwater deposits and for correlating these with the river sequences in the Thames catchment. The gravels at Ugley Quarry are unusually rich in non-durable, local and far-travelled material indicating that they were deposited very close to the edge of the ice.

The complex sequence of sands, gravels and boulder clay at this quarry shows that, during the Anglian cold stage (450,000 years ago), the Thames catchment was repeatedly invaded by ice from the north or north-west. The evidence from Ugley is critical in demonstrating that there were at least four of these ice advances, each one depositing a characteristic boulder clay.

The pit has been partly infilled. Two representative sections were intended to be maintained in the northern part of the pit.

There are several sarsen stones at the entrance to the quarry.

Glacial sands and gravels at Ugley Quarry in 1980. Photo © British Geological Survey (P212594).