Estimated Reservoir Ages of the Black Sea Since the Last Glacial

Abstract

ABSTRACT. Accelerator mass spectrometry (AMS) radiocarbon dating of ostracod and gastropod shells from the south western Black Sea cores combined with tephrochronology provides the basis for studying reservoir age changes in the lateglacial Black Sea. The comparison of our data with records from the northwestern Black Sea shows that an apparent reservoir age of -1450 14 C yr found in the glacial is characteristic of a homogenized water column. This apparent reservoir age is most likely due to the hardwater effect. Though data indicate that a reservoir age of -1450 14 C yr may have persisted until the B0lling-Aller0d warm period, a comparison with the GISP2 ice-core record suggests a gradual reduction of the reservoir age to -1000 ,4 C yr, which might have been caused by dilution effects of inflowing meltwater. During the B0lling-Aller0d warm period, soil development and increased vegetation cover in the catchment area of the Black Sea could have hampered erosion of carbonate bedrock, and hence diminished contamination by "old" carbon brought to the Black Sea basin by rivers. A fur ther reduction of the reservoir age most probably occurred contemporary to the precipitation of inorganic carbonates triggered by increased phytoplankton activity, and was confined to the upper water column. Intensified deep water formation subse quently enhanced the mixing/convection and renewal of intermediate water. During the Younger Dryas, the age of the upper water column was close to 0 yr, while the intermediate water was -900 l4 C yr older. The first inflow of saline Mediterranean water, at -8300 14 C yr BP, shifted the surface water age towards the recent value of -400 14 C yr.

Extending the analytical window for water-soluble organic matter in sediments by aqueous Soxhlet extraction

“…All sediments were clay-rich and the upper two samples (10-12, 147-162 cm) consisted of finely laminated coccolith ooze of marine Unit I in the Black Sea (Degens and Ross, 1972). 147-162 cm contained a volcanic ash layer which most likely derived from the Minoan eruption of Santorini, and therefore dates to 3.55-3.58 ka BP (Friedrich et al, 2006;Kwiecien and Haug, 2008). The sample from 420 to 435 cm consisted of clay with sand to silt-sized carbonate clasts and was deposited when the Black Sea was isolated from the Mediterranean (Black Sea Unit III; age > 8 ka BP) (Bahr et al, 2006;Kwiecien and Haug, 2008).…”

“…147-162 cm contained a volcanic ash layer which most likely derived from the Minoan eruption of Santorini, and therefore dates to 3.55-3.58 ka BP (Friedrich et al, 2006;Kwiecien and Haug, 2008). The sample from 420 to 435 cm consisted of clay with sand to silt-sized carbonate clasts and was deposited when the Black Sea was isolated from the Mediterranean (Black Sea Unit III; age > 8 ka BP) (Bahr et al, 2006;Kwiecien and Haug, 2008). The deepest sample (596-613 cm) represented a dark banded sulfide-rich clayey mud from Unit III.…”

Vegetation dynamics in the Northeastern Mediterranean region during the past 23 000 yr: insights from a new pollen record from the Sea of Marmara

“…This tephra represents the distal facies of the Cape Riva eruption of Santorini, and it had been reported in other marine sediment cores from the Sea of Marmara (Ç agatay et al, 2000;Wulf et al, 2002). The Cape Riva eruption has been dated on deposits on land, in which four dates have a mean value and standard deviation of 18 310 ± 380 14 C yr (see for details, Pichler and Friedrich, 1976;Eriksen et al, 1990;Kwiecien et al, 2008).…”

“…Siani et al (2000). b Mean and standard deviation calculated by Kwiecien et al (2008) based on original dating series (Pichler and Friedrich, 1976;Eriksen et al, 1990). …”

Modeling the Age of the Cape Riva (Y-2) Tephra

“…It is found in deep-sea sediments from the Black Sea (Kwiecien et al 2008), Aegean Sea, and the Marmara Sea («a°gatay et al 2000;Wulf et al 2002;Aksu et al 2008); in eastern Mediterranean deep-sea sediments near western Cyprus (Wulf et al 2002); in terrestrial peat records in Greece (Seymour et al 2004;Margari et al 2007;Müller et al 2011); and in a lake record in Turkey (Roeser et al 2012). Obtaining an accurate age for this tephra is important because it is frequently used to date and correlate different marine and terrestrial chronologies (e.g.…”