6 Boreal Submerged Black Sea Landscapes
81
system is not any more active. Everywhere across the mid and outer shelf the ridges,
mounds and depressions are draped by this thin layer of sediment with a remarkably
uniform thickness of no more than a meter (Lericolais et al. 2010).
6.3.2 Core Sample Information
Before the evidence of the above described wave cut terraces no reliable sea level
markers were described to allow a good sea level reconstruction (Giosan et al. 2006;
Pirazzoli 1991). More the lack of radiocarbon ages on in situ materials and the
difficulty in calibrating radiocarbon ages in a setting with variable reservoir ages
(Giosan 2007) led to ongoing discussion about the Black Sea level fluctuations.
Recent publications (Balabanov 2007) have proposed unrealistic Black Sea level
curve leading to an obvious controversy with the so far published sea level curves of
the Mediterranean Sea. Brückner et al. (2010) demonstrate that both water bodies had
reacted synchronously on glacio-eustatic changes at least since 7,500 BP, when the
Black Sea and the Mediterranean were connected. Brückner et al. (2010) documented
that none of the Mediterranean sea level curves shows the major wiggles postulated
for the Black Sea by Balabanov (2007) which are supposed to reflect transgression
and regression cycles.
Using sediment cores to reconstruct the Black Sea level fluctuation with accurate
dates is challenging. One of the reasons for this is the uncertainty existing to resolve
the reservoir age of the Black Sea. Actually, if at least for the more recent period,
Siani et al. (2000) have proposed a reservoir age of 415 ± 90 years BP for the Black
Sea, a different reservoir age of about 1,280 years deduced from the occurrence of
the Santorini Minoan ash in several south Black Sea cores recovered in deep waters
was proposed by Guichard et al. (1993). If we include documentation from Jones
and Gagnon (1994), Bahr et al. (2005) and Kwiecien et al. (2008), then reservoir
ages are extending from 0 to 1,280 years. The question of which reservoir age could
be given to old water of the “Black Lake”, depending on depth in the water column is
still a matter of debate. Recently, radiocarbon activity of dissolved inorganic carbon
has been measured in the north-western Black Sea and a contribution to sedimentary
organic carbon estimated at < 15 % of the photosynthetic primary production could
explain
14 C reservoir ages greater than 1,300 years (Fontugne et al. 2009).
Another controversy lies in the knowledge of the salinity of the Black Sea during
the New Euxinic Stage (∼ 20,000 years BP). Wall and Dale (1974) demonstrated
that sediments whose ages did not exceed 23,000 years in the cores they analysed
contain a unique dinoflagellate assemblage that comprises essentially two species,
Tectatodinium psilatum and Spiniferites cruciformis. These dinoflagellates apparently lived in the almost freshwater “lake-sea” of the New Euxinic Stage and were
displaced abruptly 7,000 years ago when saline water from the Mediterranean began
to flow into the Black Sea (Wall and Dale 1974). Although, other authors (Marret
et al. 2009; Mudie et al. 2002; Yanko-Hombach et al. 2007a) prefer to speak of a
brackish body for the Black Sea at that period. Therefore, determining the salinity of
81
system is not any more active. Everywhere across the mid and outer shelf the ridges,
mounds and depressions are draped by this thin layer of sediment with a remarkably
uniform thickness of no more than a meter (Lericolais et al. 2010).
6.3.2 Core Sample Information
Before the evidence of the above described wave cut terraces no reliable sea level
markers were described to allow a good sea level reconstruction (Giosan et al. 2006;
Pirazzoli 1991). More the lack of radiocarbon ages on in situ materials and the
difficulty in calibrating radiocarbon ages in a setting with variable reservoir ages
(Giosan 2007) led to ongoing discussion about the Black Sea level fluctuations.
Recent publications (Balabanov 2007) have proposed unrealistic Black Sea level
curve leading to an obvious controversy with the so far published sea level curves of
the Mediterranean Sea. Brückner et al. (2010) demonstrate that both water bodies had
reacted synchronously on glacio-eustatic changes at least since 7,500 BP, when the
Black Sea and the Mediterranean were connected. Brückner et al. (2010) documented
that none of the Mediterranean sea level curves shows the major wiggles postulated
for the Black Sea by Balabanov (2007) which are supposed to reflect transgression
and regression cycles.
Using sediment cores to reconstruct the Black Sea level fluctuation with accurate
dates is challenging. One of the reasons for this is the uncertainty existing to resolve
the reservoir age of the Black Sea. Actually, if at least for the more recent period,
Siani et al. (2000) have proposed a reservoir age of 415 ± 90 years BP for the Black
Sea, a different reservoir age of about 1,280 years deduced from the occurrence of
the Santorini Minoan ash in several south Black Sea cores recovered in deep waters
was proposed by Guichard et al. (1993). If we include documentation from Jones
and Gagnon (1994), Bahr et al. (2005) and Kwiecien et al. (2008), then reservoir
ages are extending from 0 to 1,280 years. The question of which reservoir age could
be given to old water of the “Black Lake”, depending on depth in the water column is
still a matter of debate. Recently, radiocarbon activity of dissolved inorganic carbon
has been measured in the north-western Black Sea and a contribution to sedimentary
organic carbon estimated at < 15 % of the photosynthetic primary production could
explain
14 C reservoir ages greater than 1,300 years (Fontugne et al. 2009).
Another controversy lies in the knowledge of the salinity of the Black Sea during
the New Euxinic Stage (∼ 20,000 years BP). Wall and Dale (1974) demonstrated
that sediments whose ages did not exceed 23,000 years in the cores they analysed
contain a unique dinoflagellate assemblage that comprises essentially two species,
Tectatodinium psilatum and Spiniferites cruciformis. These dinoflagellates apparently lived in the almost freshwater “lake-sea” of the New Euxinic Stage and were
displaced abruptly 7,000 years ago when saline water from the Mediterranean began
to flow into the Black Sea (Wall and Dale 1974). Although, other authors (Marret
et al. 2009; Mudie et al. 2002; Yanko-Hombach et al. 2007a) prefer to speak of a
brackish body for the Black Sea at that period. Therefore, determining the salinity of