Efstadalsvatn – a multi-proxy study of a Holocene lacustrine sequence from NW Iceland

摘要: Multi-proxy data, both lithostratigraphic and biostratigraphic, are presented from Efstadalsvatn, a lake in NW Iceland. The sequence covers the period 10,000 to 3500 14C yr B.P. biostratgraphic data include first Icelandic chironomid-based reconstruction of Holocene mean July air temperatures, using Norwegian training set absence modern data. results show that deglaciation ecosystem development probably began before temperatures were around 4°C at ca. 9500 Temperatures then rose 8°C time deposition Saksunarvatn tephra (9100 B.P.), reaching 10°C by 8500 B.P., high enough for growth tree birch, although successful birch colonisation did not take place until 6750 There is some evidence cooling immediately preceding 9100 little firm biostratigraphic 8200 cal. event, this may be due relatively low resolution pollen sampling interval, but there changes total carbon (TC) mass susceptibility (MS) Optimal relative vegetation stability have occurred between 8000–6100 chironomid assemblages indicate higher after 5000 This latter interpretation may, however, reflect delayed thermophilous taxa requires further investigation. lithostratigraphy greater local terrestrial instability 6100 it seems unlikely led redevelopment ice catchment. records appear degree resistence climate forcing throughout early middle Holocene. new temperature needs refined studies Iceland, particularly an set, has already demonstrated problems paleoclimatic interpretations based on and/or macrofossil alone.