Ae. Aksu et al., LATE GLACIAL-HOLOCENE PALEOCLIMATIC AND PALEOCEANOGRAPHIC EVOLUTION OF THE AEGEAN SEA - MICROPALEONTOLOGICAL AND STABLE ISOTOPIC EVIDENCE, Marine micropaleontology, 25(1), 1995, pp. 1-28
Late glacial to Holocene paleoclimatic and paleoceanographic changes a
re examined using records of calcareous and organic-walled marine micr
ofossils, pollen and terrestrial spores and oxygen isotope data in cor
es from the Aegean Sea basins. Planktic foraminiferal, coccolith and d
inoflagellate data show that the late glacial-Holocene transition in t
he region was associated with a large warming of surface water. Medite
rranean-based paleotransfer functions for planktic foraminifera show a
5 degrees-10 degrees C increase in surface water temperature from sim
ilar to 14,000 to similar to 9600 yr B.P. Estimates of surface water o
xygen isotopic composition (delta(18)O(w)) derived from planktic foram
iniferal oxygen isotopic and transfer function data indicate that this
warming was associated with a 2.0 to 2.5 parts per thousand reduction
in delta(18)O(w). Transfer function results indicate corresponding 1.
0 to 1.5 parts per thousand salinity reductions for this time (ca. 960
0-6400 yr B.P.) throughout the Aegean Sea. Pollen, dinoflagellate and
isotopic data show that the early Holocene excess fresh water originat
ed from rapid melting of the northern European and Siberian ice sheets
,supplied primarily from the Black Sea by the opening of Bosphorus and
Dardanelles Channels, during the post glacial sea-level rise, and sup
plemented by major rivers entering the Aegean Sea, Continuous outflow
of fresh water into the Aegean Sea provided a low salinity surface lid
, preventing the ventilation of the deep water. Benthic foraminifera s
hows a major turn-over that indicates low dissolved oxygen; however, b
ottom waters were not anoxic. Sapropel level S1 resulted from a combin
ation of stagnant deep water in isolated depressions, increased terrig
enous organic matter and periods of high primary productivity, as indi
cated by pollen and dinocysts, respectively. The surface water tempera
ture and salinity reached present-day values at similar to 6400 yr B.P
., with little subsequent change despite the major deforestation onsho
re.