Multi‐proxy evidence for early to mid‐Holocene environmental and climatic changes in northeastern Poland     

STEFAN LAUTERBACH  ACHIM BRAUER  NILS ANDERSEN  DAN L. DANIELOPOL  PETER DULSKI  MATTHIAS HÜLS  KRYSTYNA MILECKA  TADEUSZ NAMIOTKO  BIRGIT PLESSEN  ULRICH VON GRAFENSTEIN  DECLAKES PARTICIPANTS 《Boreas: An International Journal of Quaternary Research》2011,40(1):57-72

Lauterbach, S., Brauer, A., Andersen, N., Danielopol, D. L., Dulski, P., Hüls, M., Milecka, K., Namiotko, T., Plessen, B., von Grafenstein, U. & DecLakes participants 2010: Multi‐proxy evidence for early to mid‐Holocene environmental and climatic changes in northeastern Poland. Boreas, 10.1111/j.1502‐3885.2010.00159.x. ISSN 0300‐9483. We investigated the sedimentary record of Lake Hańcza (northeastern Poland) using a multi‐proxy approach, focusing on early to mid‐Holocene climatic and environmental changes. AMS ¹⁴C dating of terrestrial macrofossils and sedimentation rate estimates from occasional varve thickness measurements were used to establish a chronology. The onset of the Holocene at c. 11 600 cal. a BP is marked by the decline of Lateglacial shrub vegetation and a shift from clastic‐detrital deposition to an autochthonous sedimentation dominated by biochemical calcite precipitation. Between 10 000 and 9000 cal. a BP, a further environmental and climatic improvement is indicated by the spread of deciduous forests, an increase in lake organic matter and a 1.7‰ rise in the oxygen isotope ratios of both endogenic calcite and ostracod valves. Rising δ¹⁸O values were probably caused by a combination of hydrological and climatic factors. The persistence of relatively cold and dry climate conditions in northeastern Poland during the first one and a half millennia of the Holocene could be related to a regional eastern European atmospheric circulation pattern. Prevailing anticyclonic circulation linked to a high‐pressure cell above the retreating Scandinavian Ice Sheet might have blocked the influence of warm and moist Westerlies and attenuated the early Holocene climatic amelioration in the Lake Hańcza region until the final decay of the ice sheet.  相似文献