Temporal changes in Holocene δ¹⁸O records from the northwest and central North Iceland Shelf

Abstract

The region of north Iceland is highly sensitive climatically owing to its location with respect to atmospheric and oceanographic fronts. In this study we present total carbonate and 18 O records of benthic and planktic Foraminifera from nine sediment cores from the North Iceland Shelf. The results of this work indicate that the deglaciation of the Vestfirdir Peninsula was completed by 10 200 cal. yr BP. The 8200 cal. yr BP cold event is present only as a minor isotopic event, and seems not to have had much of a cooling effect on the bottom waters of the northwest Iceland shelf. The Holocene maximum warmth, attributed to a stronger North Icelandic Irminger Current, occurred between ca. 7800 and 6200 cal. yr BP. Over the past 4500 cal. yr BP a general cooling trend has occurred on the North Iceland Shelf, and superimposed on this overall cooling trend are a number of oscillations between periods when relatively warmer and cooler waters occupied the shelf. Relatively cooler waters were present at 4200-4000 cal. yr BP, 3200-2900 cal. yr BP, 2500-2350 cal. yr BP and 600-200 cal. yr BP, whereas relatively warmer waters were present on the shelf at 3750-3450 cal. yr BP, 2800-2600 cal. yr BP and 1700-1000 cal. yr BP.

A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650

“…Data sets from the North Icelandic shelf show general patterns of surface and bottom water cooling initiated between AD 1200 and 1350, with intensification of cooling after AD 1550-1600 (e.g. Castañeda et al, 2004;Jiang et al, 2005;Andresen et al, 2005;Eiríksson et al, 2006;Massé et al, 2008;Andrews et al, 2009) due to a relative greater contribution of polar waters as opposed to Atlantic waters (Jiang et al, 2007). While the broad scale changes are in accordance with the terrestrial records, as noted by Andrews et al (2009), suggesting close coupling between the marine and atmospheric temperatures, in general the majority of marine cores lack the temporal resolution to compare with detailed terrestrial reconstructions.…”

Two millennia of North Atlantic seasonality and implications for Norse colonies

“…Samples were reacted with 103% phosphoric acid at 70°C by using a Kiel III carbonate preparation device directly coupled to a Thermo-Finnigan MAT 253 gas-isotoperatio mass spectrometer, in the Saskatchewan Isotope Laboratory. Isotopic analyses were corrected for phosphoric acid fractionation and contribution of 17 …”

“…Marine cores contain abundant paleoclimatic proxy data, including carbonate content, foraminiferal diversity, and ice-rafted debris. Recent investigations of the marine environment off the northwest and northern coasts of Iceland have revealed significant millennial-, centennial-, and decadal-scale variability over the Holocene (14)(15)(16)(17)(18)(19). These hydrographic changes on the north Icelandic shelf reflect larger scale oceanatmosphere circulation changes and regional climate variation in the North Atlantic.…”

Holocene Sediment Magnetic Properties along a Transect From Ísafjardardjúp to Djúpáll, Northwest Iceland

“…The extent of ice in the area during the LGM is uncertain, but there is evidence for ice extending onto the continental shelf (Geirsdó ttir et al, 2002). Iceberg rafting of sediments from Iceland glaciers ceased along the north coast by 10,000 cal yr. BP (Castañ eda, 2001;Castañ eda et al, 2004). Questions remain regarding the presence or absence of the ice cap on the uplands during the Holocene thermal maximum (Kaufman et al, 2004) and the timing of glacier expansion during the Neoglaciation (Wastl et al, 2001).…”