Abrupt changes of temperature and water chemistry in the late Pleistocene and early Holocene Black Sea
Arz, Helge W.
Major, Candace O.
MetadataShow full item record
New Mg/Ca, Sr/Ca, and published stable oxygen isotope and 87Sr/86Sr data obtained on ostracods from gravity cores located on the northwestern Black Sea slope were used to infer changes in the Black Sea hydrology and water chemistry for the period between 30 to 8 ka B.P. (calibrated radiocarbon years). The period prior to 16.5 ka B.P. was characterized by stable conditions in all records until a distinct drop in δ 18O values combined with a sharp increase in 87Sr/86Sr occurred between 16.5 and 14.8 ka B.P. This event is attributed to an increased runoff from the northern drainage area of the Black Sea between Heinrich Event 1 and the onset of the Bølling warm period. While the Mg/Ca and Sr/Ca records remained rather unaffected by this inflow; they show an abrupt rise with the onset of the Bølling/Allerød warm period. This rise was caused by calcite precipitation in the surface water, which led to a sudden increase of the Sr/Ca and Mg/Ca ratios of the Black Sea water. The stable oxygen isotopes also start to increase around 15 ka B.P., although in a more gradual manner, due to isotopically enriched meteoric precipitation. While Sr/Ca remains constant during the following interval of the Younger Dryas cold period, a decrease in the Mg/Ca ratio implies that the intermediate water masses of the Black Sea temporarily cooled by 1–2°C during the Younger Dryas. The 87Sr/86Sr values drop after the cessation of the water inflow at 15 ka B.P. to a lower level until the Younger Dryas, where they reach values similar to those observed during the Last Glacial Maximum. This might point to a potential outflow to the Mediterranean Sea via the Sea of Marmara during this period. The inflow of Mediterranean water started around 9.3 ka B.P., which is clearly detectable in the abruptly increasing Mg/Ca, Sr/Ca, and 87Sr/86Sr values. The accompanying increase in the δ 18O record is less pronounced and would fit to an inflow lasting ∼100 a.
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008): Q01004, doi:10.1029/2007GC001683.
Suggested CitationGeochemistry Geophysics Geosystems 9 (2008): Q01004
Showing items related by title, author, creator and subject.
Temporal and spatial variability in sedimentation in the Black Sea : cruise report R/V Knorr 134-8, Black Sea Leg 1, April 16-May 7, 1988 Honjo, Susumu; Hay, Bernward J.; Members of the Scientific Shipboard Party (Woods Hole Oceanographic Institution, 1988-10)This document represents the cruise report of the highly successful Leg 1 of the R/V Knorr cruise to the Black Sea (Cruise 134-8) as a joint Turkish-American Oceanographic Expedition (Izmir to Istanbul, April 16 to May ...
Testing the physical oceanographic implications of the suggested sudden Black Sea infill 8400 years ago Siddall, M.; Pratt, Lawrence J.; Helfrich, Karl R.; Giosan, Liviu (American Geophysical Union, 2004-03-17)We apply a shock-capturing numerical model based on the single-layer shallow water equations to an idealized geometry of the Black Sea and the Sea of Marmara in order to test the implications of a suggested sudden Black ...
King, Linda L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1992-11)This thesis examines the degradation pathways of chlorophyll in the Black Sea water column and sediments. Measurements are made of total chlorophyll in sediment traps from two locations and depths in the water column, ...