Holocene environmental change in theSkallingen area, easternNorthGreenland, based on a lacustrine record

Abstract

A lacustrine record from a small lake, Lille Sneha Sø, in the Skallingen area indicates that the region was deglaciated in the early Holocene, prior to 8000 cal. a BP. Deglaciation was probably triggered by high temperatures, but it took more than 1000 years for the lake and the catchment to stabilize. Chironomids were amongst the first invertebrates to colonize the lake. The fossil chironomid assemblage is fairly rich and comparable to other records from further south in Greenland. The pioneer vegetation in the area consisted of mosses and herbaceous plants. The oldest remains of woody plants (Salix arctica) are dated to c. 7700 cal. a BP, and remains of Dryas integrifolia appear at around 6700 cal. a BP; these are the only woody plants recorded. Maximum concentrations of chironomids, maximum occurrence of ephippia of the water flea Daphnia pulex, highest organic matter contents and lowest minerogenic input from c. 7700 to 4400 cal. a BP probably reflect the Holocene thermal maximum (HTM). The highest temperatures during the HTM are indicated around 7000 cal. a BP, when Salix arctica, which is considered a warmth‐loving plant, had a maximum. Comparisons with Holocene records from East and North Greenland show similar immigration histories and similar trends, with the Little Ice Age as the coldest period during the Holocene, culminating about 150 years ago. Subsequent warming does not indicate environmental conditions comparable to the HTM yet at this stage. The occurrence of several warmth‐demanding species particularly in the early Holocene sediments indicates redeposition and implies that temperatures in the past, most likely during an interglacial period, were significantly higher than during the HTM.

Timing and magnitude of early to middle Holocene warming in East Greenland inferred from chironomids

“…Studies of chironomid assemblages in surface sediments along spatial and climatic transects have repeatedly demonstrated that temperature is a dominant predictor of chironomid species distributions (e.g. Pioneering qualitative palaeoclimate interpretations from chironomid assemblages have been published for several sites in eastern and northeastern Greenland (Wagner et al 2005;Schmidt et al 2011;Wagner & Bennike 2015). Pioneering qualitative palaeoclimate interpretations from chironomid assemblages have been published for several sites in eastern and northeastern Greenland (Wagner et al 2005;Schmidt et al 2011;Wagner & Bennike 2015).…”

Holocene environmental history in high‐Arctic North Greenland revealed by a combined biomarker and macrofossil approach

“…A third overlapping sediment core below 105 cm composite depth (obtained using the Russian corer) revealed silty and sandy sediments, which according to the results from studies of nearby Lille Sneha Sø (Figs 1, 2) most likely represent the deglaciation of the area (Wagner & Bennike 2015). However, radiographic scanning with an ITRAX core scanner (Cox Co., Sweden) allowed optical correlation of the sediment cores.…”

“…The most common are worn stem fragments of the bryophyte Scorpidium scorpioides. As mentioned by Wagner & Bennike (2015), L. arcticus is fairly widespread in Greenland, but it has not been found in the northernmost parts, including the Trifna Sø area. Scorpidium scorpioides may be characterized as fairly warmthdemanding because it is very rare in North Greenland (Holmen 1960).…”

“…Continental sedimentary records from high-Arctic North Greenland are scarce and often poorly constrained chronologically (Fredskild 1973(Fredskild , 1995Funder & Abrahamsen 1988;Olsen et al 2011;Perren et al 2012;Wagner & Bennike 2015). Previous palynological and macrofossil data from Klaresø, Sommersø and Lille Sneha Sø show that the HTM was characterized by immigration of relative warmth-indicating species such as Salix arctica as well as occurrences of aquatic invertebrates indicating prolonged ice-free summers, e.g.…”

“…Daphnia pulex, Apatania zonella and Chironomidae (Fredskild 1973;Funder & Abrahamsen 1988;Wagner & Bennike 2015). ka BP (Wagner & Bennike 2015). ka BP and ended around 4.4 cal.…”