| Popis: |
Coastal sand dunes are common in Britain, especially along western Atlantic coasts, and archaeological sites are well preserved under blown sand. One of the questions is how Holocene palaeoclimate variation influences patterns of settlement establishment and abandonment. Few studies of coastal sites have included palaeoenvironmental evidence, and even fewer include securely dated stratigraphy. This study uses a multi proxy approach to investigate two main and five minor coastal sites in Cornwall, with molluscs analyses being the principal analytical method. Chronology is established by radiocarbon dating and optically stimulated luminescence so that episodic human activity can be related to periods of sand blow and instability. Evidence is sought concerning the history of mineral mining in the Red River catchment area. Twenty three cores and a test pit were examined along a transect at the multi period site at Gwithian on the north Cornish coast. Mollusc columns were obtained at Strap Rocks near the main Gwithian site, and from five trenches excavated at the early medieval site of Gunwalloe on the Lizard peninsula. The study establishes that initial sand deposition was about 3000 BC, with further marked periods of sand blow in the early and late Bronze Age, the Iron Age and the mid-medieval period. Some, but not all, sand blow correlates with periods of settlement occupation and abandonment, and with known palaeoclimate episodes such as the Little Ice Age. Difficulty in establishing periods of sand conflation and deflation and how this may lead to errors in chronology are discussed. There is weak evidence for mining activity in the Bronze Age, but strong evidence from c 1050 AD. The chronology of mollusc extinctions and introductions is refmed, e.g. Xerocrassa geyeri did not become extinct until the end of the early Bronze Age and Cochlicella acuta was present from the late Neolithic, about 2400 BC. |
