دانلود رایگان مقاله وضعیت بینهایت مرطوب منطبق با ترک عصر مفرغ

Abstract

Abandonment of farming systems on upland areas in southwest Britain during the Late Bronze Age – some 3000 years ago – is widely considered a ‘classic’ demonstration of the impact of deteriorating climate on the vulnerability of populations in such marginal environments. Here we test the hypothesis that climate change drove the abandonment of upland areas by developing new chronologies for human activity on upland areas during the Bronze Age across southwest Britain (Dartmoor, Exmoor and Bodmin Moor). We find Bronze Age activity in these areas spanned 3900–2950 calendar years ago with abandonment by 2900 calendar years ago. Holocene Irish bog and lake oak tree populations provide evidence of major shifts in hydroclimate across western Britain and Ireland, coincident with ice rafted debris layers recognized in North Atlantic marine sediments, indicating significant changes in the latitude and intensity of zonal atmospheric circulation across the region. We observe abandonment of upland areas in southwest Britain coinciding with a sustained period of extreme wet conditions that commenced 3100 calendar years ago. Our results are consistent with the view that climate change increased the vulnerability of these early farming communities and led to a less intensive use of such marginal environments across Britain.

4. Conclusions

Extreme wet conditions during the late Bronze Age have been widely cited as the principal driver of less intensive use of Dartmoor andother upland areas of southwestBritain. Unfortunately,previous studies have relied on limited radiocarbon dating age control and low-resolution records of inferred climate changes to make comparisons. Here we have undertaken a comprehensive study of published radiocarbon ages from archaeological contexts across upland areas reported over the past three decades and compared to the Irishbogandlakesidepopulationdatawhichcanbe regardedas a highly-sensitive and precisely-dated measure of wetness for western Britain and Ireland. By calibrating charcoal and wood archaeological ages, we observe an apparent relationship between the end of human activity across upland areas in southwest Britain and a period of maximum wetness around 2950 cal. BP, coincident with the late Bronze Age. Our results support the argument that farming communities operating in marginal environments were highly vulnerable to climate change in the past and that adaptation wasmostprobably throughmigration tolowland areas. Furtherwork is now needed for more targeted archaeological investigations to comprehensively date records spanning the Bronze and Iron ages across the region