Original paper

Palaeoenvironmental investigations of the Holocene sedimentary record of the Garding-2 research drill core, northwestern Germany

Proborukmi, Maria Sekar; Urban, Brigitte

Abstract

A 20 m section of calcareous, fine- to coarse-grained Holocene sediments forming the upper part of the Garding-2 core, taken near Garding on the Eiderstedt Peninsula in Northwest Germany, has been analysed for pollen and for its sedimentological and geochemical characteristics to reconstruct the Holocene environmental history of this coastal area. The studied sediment sequence was deposited above an unconformity at 20 m depth formed by major erosion due to the rapid sea-level rise in the Early Holocene. A thin layer of marine sediments at the base, possibly correlating to the late Atlantic, is unconformably overlain by marine-tidal flat deposits up to 11.00 m depth. The Subboreal age of these deposits is evidenced by the first occurrence of Fagus at 15.97 m, which is OSL-dated, at 16.22 m, to about 3130 ± 260 BP (Zhang et al. 2014) and Carpinus at 15.03 m. The Ulmus decline, a palynological characteristic marking the Atlantic to Subboreal transition in northwestern Europe, is not revealed in the pollen sequence. Ulmus shows low values throughout the entire pollen diagram. It is therefore assumed that late Atlantic transitional sediments were eroded in Garding-2. Sandy sediments between about 11.00 m and the top of the sequence are palynologically characterised by increased representation of local salt marsh, dune and tidal flat vegetation, indicated by the abundance of Poaceae, Cerealia-type pollen, probably derived mainly from wild grasses, and increased percentages of Ericaceae, Cyperaceae and Chenopodiaceae. These upper deposits are AMS 14 C-dated to 2790 ± 20 BP (at 11.41 m) and 1820 ± 50 BP (at 2.70 m; Zhang et al. 2014) suggesting an early Subatlantic age. Due to regional features and peculiarities of the coastal environment, significant anthropogenic impact on landscape as well as the expansion of Fagus and Carpinus, characteristic for the Subboreal to Subatlantic transition at about 2700 BP in Northern Germany, are not clearly reflected in the pollen diagram.

Keywords

holocenepalynologynorthwest germanyeiderstedt peninsulacoastal environmentssedimentology