A paleoecological reconstruction of the Late Glacial and Holocene based on multidisciplinary studies at Steregoiu site (Gutai Mts., Romania)

Abstract

High resolution analyses of pollen, mineral magnetic properties, loss of ignition, lithostratigraphy and AMS 14C measurements of lake sediments and peat deposits accumulated in the former crater lake of Steregoiu (Gutâiului Mts., NW Romania), gave new and important information about vegetation and climate changes from the period GS-2 to the present. During the Lateglacial, three cold events were recorded: before 14,700 cal. years BP (GS-2), 14,050–13,800 cal. years BP (GI-1d), 12,900-11,500 cal. years BP (GS-1), and a warm climatic event between 13,800-12,950 cal. years BP (GI-1c to GL-1a). The Late Glacial/Holocene transition around 11,500 cal. years BP, was determined by an expansion of Betula, Alnus and Picea, followed by a rapid and strong expansion of Ulmus. At 10,700 cal. years BP, dense and highly diverse forests with Ulmus, Quercus, Tilia, Fraxinus and a few Acer and Corylus individuals dominated the area. Corylus and Picea were the dominant species in the forests from 10,150 to 8,500 cal. years BP. The first occurrence of single Fagus pollen grains was around 8,000 cal years BP. Only at 4,700 cal year BP Fagus and Carpinus became widespread and established trees in the local woodlands.