A LACUSTRINE RECORD OF ENVIRONMENTAL HISTORY FROM LAKE BIRKAT RAM, GOLAN HEIGHTS (ISRAEL)

SCHWAB, Markus J.¹, NEUMANN, Frank², FRANK, Ute¹, NEGENDANK, Jörg F. W.¹, LITT, Thomas² and STEIN, Mordechai³, (1)GeoForschungsZentrum Potsdam, Sect. 3.3 Climate Dynamics and Sediments, Telegrafenberg, Potsdam, D-14473, Germany, (2)Inst. of Paleontology, Univ of Bonn, Nussallee 8, Bonn, D-53115, Germany, (3)Hebrew Univ and Geol Survey of Israel, Jerusalem, 91904, Israel, mschwab@gfz-potsdam.de

In 1999 we raised three short sediment cores from lake Birkat Ram (33°15´N, 35°40´E), located about 940m asl. near the Mt. Hermon (2025 m asl.). The diameter is 900 m N-S and 650 m E-W. Water depth measurements were only 1.5 m (1999), though described fluctuations are 6 to 12 m (Ehrlich & Singer 1978). The lake water is fresh and receives most of its water from precipitation, surface run-off and is secondarily nourished by subaquatic springs (Ehrlich & Singer 1978).

Based on sedimentological analysis, pollen analysis and high-resolution logs on magnetic susceptibility, a 543 cm composite profile was created. By means of AMS 14C dates we estimate the age of the core at approx. 6000 yrs. The presented timescale is based on eleven AMS 14C dates on wood and lacustrine plant-macrofossils. Additionally investigations on macro-relicts for 14C age determinations and geochemical analysis (TOC, XRF) are currently in progress in order to determine the reservoir effect.

The palynological study shows evidence of vegetational changes during the last 6000 years, interpreted to be mainly the result of human activities. A mediterranean vegetation is recorded as the main component in the pollen flora (woodlands and maquis). Furthermore, the inluence of Irano-Turanian steppe vegetation and montane vegetation of Mount Hermon is in evidence. Two periods with high Olea-, Juglans and Vitis-values, accompanied by low Quercus-values, show intense land use in the Chalcolithic, the Early Bronze Age and the Hellenistic-Roman-Byzantine Period. The Middle and Late Bronze Age, the Iron Age as well as the Arab-Osman Period feature extremely high Quercus-values. Basic cause might be the decrease of the area of cultivation and the following forest regeneration as a consequence of nomadism.

The recorded paleo- and rock magnetism variations agree with the results of archeomagnetic investigations in the Near East. Therefore it can be assumed that the paleosecular variation records are characteristic for the Late Holocene in this region.

Ehrlich & Singer 1978: Israel J. Earth Sc. 25

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XVI INQUA Congress

A LACUSTRINE RECORD OF ENVIRONMENTAL HISTORY FROM LAKE BIRKAT RAM, GOLAN HEIGHTS (ISRAEL)