CPClimate of the PastCPClim. Past1814-9332Copernicus GmbHGöttingen, Germany10.5194/cp-11-1785-2015Reconstruction of MIS 5 climate in the central Levant using a stalagmite from
Kanaan Cave, LebanonNehmeC.carole.nehme@naturalsciences.behttps://orcid.org/0000-0003-0004-0910VerheydenS.NobleS. R.FarrantA. R.SahyD.HellstromJ.DelannoyJ. J.ClaeysP.https://orcid.org/0000-0002-4585-7687Department of Earth and History of Life, Royal Institute of Natural
Sciences (RBINS), Brussels, BelgiumAnalytical, Environmental & Geo-Chemistry, Department of Chemistry,
Faculty of Sciences, Vrije Universiteit Brussel, Brussels, BelgiumNERC Isotope Geosciences Laboratory, Keyworth, Nottingham, NG12 5GG,
UKBritish Geological Survey, Keyworth, Nottingham, NG12 5GG, UKGeochemistry Laboratory, Earth Science Department, University of
Melbourne, Melbourne, AustraliaLaboratoire EDYTEM UMR5204 CNRS, Université de Savoie,
Bourget-du-Lac, FranceC. Nehme (carole.nehme@naturalsciences.be)21December201511121785179917June201517July201526November20157December2015This work is licensed under a Creative Commons Attribution 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/This article is available from https://cp.copernicus.org/articles/11/1785/2015/cp-11-1785-2015.htmlThe full text article is available as a PDF file from https://cp.copernicus.org/articles/11/1785/2015/cp-11-1785-2015.pdf
Lying at the transition between the temperate Mediterranean domain and
subtropical deserts, the Levant is a key area to study the palaeoclimatic
response over glacial–interglacial cycles. This paper presents a precisely
dated last interglacial (MIS 5) stalagmite (129–84 ka) from the Kanaan
Cave, Lebanon. Variations in growth rate and isotopic records indicate a
warm humid phase at the onset of the last interglacial at ∼ 129 ka that lasted until ∼ 125 ka. A gradual shift in speleothem
isotopic composition (125–122 ka) is driven mainly by the δ18O
source effect of the eastern Mediterranean surface waters during sapropel 5 (S5). The onset of glacial inception began after ∼ 122 ka,
interrupted by a short wet pulse during the sapropel 4 (S4) event. Low growth rates and
enriched oxygen and carbon values until ∼ 84 ka indicate a
transition to drier conditions during Northern Hemisphere glaciation.
The eastern Mediterranean showing the location of palaeoclimate
records including this study and the major wind trajectories (Saaroni et
al., 1998), including the mid-latitude westerlies, and occasional incursions
from the Sharav cyclone and the Sharqiya. The north–south and east–west
precipitation gradients are indicated by dashed dark lines (isohyets in mm). CL: Cyprus Low. The locations of Kanaan Cave and other Levantine
palaeoclimatic records spanning the MIS 5 period cited in the text are
numbered 1 to 14. Records derived from marine studies are indicated by
points, lake level reconstructions and pollen data by rectangles, and
speleothems by stars. (1) Core MD 70-41 (Emeis et al., 2003); (2) core LC21
(Grant et al., 2012); (3) core ODP Site 967 (Rohling et al., 2002, 2004;
Emeis et al., 2003; Scrivner et al., 2004); (4) core ODP Site 968 (Ziegler
et al., 2010); (5) Kanaan Cave; (6) Peqiin Cave (Bar-Matthews et al., 2003);
(7) West Jerusalem Cave (Frumkin et al., 1999, 2000); (8) Soreq Cave
(Bar-Matthews et al., 2000, 2003); (9) Tsavoa Cave (Vaks et al., 2006, 2013);
(10) Negev composite speleothems from Ashalim, Hol-Zakh, and
Ma'ale-ha-Meyshar caves (Vaks et al., 2010); (11) lakes of the Dead Sea
basin (Kolodny et al., 2005; Waldmann et al., 2009; Lisker et al., 2010);
(12) lake formation at Mudawwara (Petit-Maire et al., 2010); (13) Yammouneh palaeolake (Develle et al.,
2011; Gasse et al., 2011, 2015); and (14) Lake Van (Shtokhete et al., 2014; Litt
et al., 2014).
Introduction
Located at the interface between mid- and high-latitude climate systems, and
affected by both the North Atlantic Oscillation and the monsoonal system
over Africa, the Levant region (eastern Mediterranean Basin) has the unique
potential to record the occurrence of climatic changes in both systems.
Known for its long record of prehistoric human settlements, the Levant
straddles the transition zone between the more humid Mediterranean climate
in the north and the arid Saharo-Arabian desert climate regime in the south.
This transition zone is characterized by steep precipitation and temperature
gradients. Over the past decade, several studies have attempted to
understand the palaeoclimate of this critical region (Fig. 1a) using both
marine (Kallel et al., 1997; Rossignol-Strick and Paterne, 1999; Emeis et
al., 2003) and continental palaeoclimate records (Frumkin et al., 2000;
Bar-Matthews et al., 2003; Kolodny et al., 2005; Develle et al., 2011;
Ayalon et al., 2013; Vaks et al., 2010; Gasse et al., 2015). A key period
for understanding the climate system in the Levant is the last interglacial:
Marine Isotope Stage (MIS) 5. This is generally considered to be a warm
period, comparable to the present-day climate, although this is still under
considerable debate (Vaks et al., 2003; Lisker et al., 2010; Ayalon et al.,
2002, 2013; Bar-Matthews, 2014). However, discrepancies between different
palaeoclimate archives exist, particularly between speleothem and lacustrine
archives. In particular, inconsistencies between records from the Negev Desert
(Vaks et al., 2003, 2006), central Israel/Palestine (Bar-Matthews et al.,
2000, 2003; Frumkin et al., 2000), and Lebanon (Develle et al., 2011; Gasse
et al., 2011, 2015), as well as between the eastern Mediterranean coastline (Ayalon
et al., 2013) and inner basins (e.g. Dead Sea basin, DSB; Kolodny et al., 2005;
Enzel et al., 2008; Lisker at al., 2010), are evident. In particular,
speleothem isotopic records of Soreq, Peqiin, and West Jerusalem caves
suggest the interglacial optimum was wet, but low lake levels in the DSB are indicative of drier conditions during the same period.
Whereas these different continental records reflect changes in atmospheric
circulation, regional topographic patterns, and/or site-specific climatic and
hydrological factors, the lack of detailed, accurately dated long-term
records from the northern Levant, especially from different continental
archives, limits our understanding of the regional response to climatic
conditions during MIS 5. This lack of data restricts the opportunities to
resolve the inconsistencies between palaeoclimate records across the region.
This study attempts to resolve this by providing a new high-resolution
record obtained from a speleothem from a cave in the northern Levant.
Speleothems are secondary chemical cave deposits, which provide
high-resolution proxy tools for palaeoclimate reconstruction (Genty et al.,
2001; Drysdale et al., 2007, 2009). Recent studies highlight the
significance of speleothem records, in particular for achieving precise
chronologies of continental climate changes (Wang et al., 2001; Genty et
al., 2003, 2006; Fairchild et al., 2006; Verheyden et al., 2008, 2015; Cheng
et al., 2009, 2015). In this paper, we examine the petrography, growth
history, and stable isotope geochemistry of a stalagmite from Kanaan Cave,
situated close to the Mediterranean coast on the western flank of Mount
Lebanon near Beirut, Lebanon. This speleothem provides a precise U–Th-dated
continental record of climate history from the northern Levant spanning the
last interglacial and the glacial inception of this region.
Climate and palaeoclimatic setting
Lebanon is located in the northern Levant between latitudes
33∘03′ N and 34∘41′ N (Fig. 1). The
western side of the country is characterized by a Mediterranean climate with
an annual precipitation varying between 880 and 1100 mm along the coastline
(Republic of Lebanon, 2003 – Official Report No. 28766-LE). The climate is
seasonal, with wet winters (between November and February) and dry, hot
summers (from May to October). The present climate is influenced by the
Atlantic westerlies, which bring in moist winds associated with
extra-tropical cyclones. These originate in the Atlantic and track east
across the Mediterranean Sea, forming a series of subsynoptic low-pressure
systems. In winter, outbreaks of cold air plunging south over the relatively
warm Mediterranean enhance cyclogenesis, creating the Cyprus Low (Fig. 1).
These low-pressure systems drive moist air onshore, generating intense
orographic rainfall across the mountains of the northern Levant. The
duration, intensity, and track of these storm systems strongly influence the
amount of rainfall in this region.
Conditions during the last interglacial period (LIG) are thought to have
been similar to that of today. Marine Isotope Stage 5 is generally known as
a period of minimum ice volume between 130 and 75 ka
(Emiliani, 1955). The
LIG, often defined as being equivalent to MIS 5e
(Shackleton et al., 2002), was characterized by a global mean surface
temperature less than 2 ∘C than present (Otto-Bliesner et al.,
2013), caused by the orbital forcing of insolation (Berger and Loutre,
1991). The mean sea level stood 4 to 6 m higher than present (Kopp et al.,
2009), with an important contribution from the Greenland ice sheet (Cuffey
and Marshall, 2000). The warmest interval, MIS 5e, was followed by two cold
episodes in the ocean (MIS 5d and MIS 5b), alternating with two warmer
periods (MIS 5c and MIS 5a).
In the eastern Mediterranean Basin, periods of anoxic conditions associated
with the formation of sapropels during MIS 5 are generally related to wet
conditions. These horizons are considered to have formed during periods of
increased discharge down the River Nile (Rohling et al., 2002, 2015b; Scrivner
et al., 2004), linked to enhanced low-latitude hydrological activity in the
Nile headwaters. This peak in rainfall corresponds closely with high summer
insolation (Rohling et al., 2002; Moller et al., 2012) and with minima in
the precession cycle (Lourens et al., 1996). At that time, the eastern
Mediterranean region also experienced enhanced pluvial conditions (Cheddadi
and Rossignol-Strick, 1995; Rossignol-Strick and Paterne, 1999; Kallel et
al., 2000). Wet conditions are demonstrated by pollen assemblages found
within the sapropel 5 (S5) event from the northeastern Mediterranean Basin (Cheddadi and
Rossignol-Strick, 1995).
Onshore, the climate in the Levant region during MIS 5 has been
reconstructed from lacustrine records from interior lake basins such as the
Dead Sea and Yammouneh (Kolodny et al., 2005; Gasse et al., 2011, 2015) and
speleothem records from central and southern Israel (Frumkin et al., 1999,
2000; Bar-Matthews et al., 1999, 2000, 2003; Ayalon et al., 2013, Vaks et
al., 2006, 2010). These archives suggest that climate was generally wet and
cold during Termination II (∼140–130 ka). After Termination II, the
region experienced an intense warm period coinciding with the development of S5 in the eastern Mediterranean (Rossignol-Strick and Paterne,
1999; Emeis et al., 2003; Rohling et al., 2002; Ziegler et al., 2010). From
∼130 to 120 ka, speleothem records from the Peqiin, Soreq, and West
Jerusalem caves show periods of rapid growth and decrease in δ18O values mainly attributed to higher rainfall, suggesting conditions
were wetter than during the early Holocene period (Bar-Matthews et al., 2000,
2003). Corresponding high-δ13C records (∼ 0 ‰) approaching those of the host carbonate were
interpreted as a consequence of soil denudation due to high surface runoff
in Soreq Cave (Bar-Matthews et al., 2003). However, relatively high
(∼-5 ‰) and fluctuating δ13C
in West Jerusalem Cave suggest extremely dry and unstable conditions
during which a C4 vegetation type was introduced in this area (Frumkin et
al., 2000). Gasse et al. (2011, 2015) suggest wet conditions (∼125–117 ka) as shown in the pollen assemblages and oxygen isotopes from the
Yammouneh palaeolake, in northern Lebanon. In contrast, the DSB,
located to the south (Fig. 1), remained dry during this period (Kolodny et al.,
2005). The Samra, Amora, and Lisan lakes, precursors of the Dead Sea, showed
lower stands than during the Holocene, even though a slight rise occurred
during the last interglacial maximum (Waldmann et al., 2009).
The return to slightly drier conditions, as suggested by an increase in
δ18O in speleothems from the Soreq and Peqiin caves is dated at
∼ 118–120 ka (Bar-Matthews et al., 2000, 2003). Lower
rainfall amounts prevailed until 110 ka. But the decrease in δ13C in speleothems from these caves (Fig. 1) evidences a reintroduction
of a C3 vegetation cover, indicative of wet conditions (Frumkin et al.,
2000). In northern Lebanon the Yammouneh palaeolake records (Develle et al.,
2011) located at higher altitude suggest seasonal changes with wet winters,
dry summers, and expanded steppe vegetation cover.
From ∼110 to ∼100 ka, a moderate wet period is suggested by
depleted δ18O values in speleothems from the Soreq and Peqiin caves
and by an increase in arboreal pollen taxa in northern Lebanon (Develle et
al., 2011). This coincides with anoxic conditions (sapropel 4, S4) in the eastern
Mediterranean (Emeis et al., 2003). Between ∼100 and ∼85 ka, a
return to a slightly drier climate is suggested by speleothem deposition in
both the Soreq and Peqiin caves with an increase in δ18O
values. However, the continued and more stable C3 vegetation cover (Frumkin
et al., 2000) in West Jerusalem Cave and the minor lake level increase in
the DSB suggest that the climate was probably wetter in the DSB (Waldmann et al., 2009). In northern Lebanon, the high-altitude
Yammouneh palaeolake records suggest seasonal variations with steppe
vegetation cover similar to the MIS 5d period.
From ∼85.0 to ∼75.0 ka, the last wet and warm phase of MIS 5
occurred in the Levant, corresponding with the sapropel 3 (S3) event in the eastern
Mediterranean. In the Soreq, Peqiin (Bar-Matthews et al., 1999, 2003), and
Ma'aele Effrayim caves (Vaks et al., 2003, 2006), depleted speleothem
δ18O values suggest a moderate wet period at this time in
agreement with the increase in arboreal pollen taxa in the Yammouneh
lacustrine record (Develle et al., 2011). However, the level of Lake Samra
in the DSB decreased significantly (Waldmann et al., 2009) and
little speleothem deposition occurred in caves situated in the Negev Desert
(Fig. 1) after MIS 5c (Vaks et al., 2006, 2010), both suggesting a drier
climate during MIS 5a in the south of the region.
It is clear that there are significant discrepancies between the climatic
records between the northern (Lebanon, northern Syria, and southeastern Turkey) and
southern Levant (Jordan, Israel/Palestine), possibly driven by a strong
north–south palaeoclimatic gradient that varied dramatically in amplitude
over short distances and different climatic trends (wet/dry) especially
during MIS 5e. In the northern Levant, few records span the MIS 5 period
(Gasse et al., 2011, 2015; Develle et al., 2011). New well-dated speleothem
records are needed from this area to decipher if and when the climatic
changes that are well recorded in the southern Levant (DSB and the Soreq and Peqiin caves on the Judean Plateau) also affected the northern
Levant (Yammouneh, western Mount Lebanon). What is still unclear is how the
entire region has responded to the North Atlantic/Mediterranean system
versus the southern influences linked to the monsoon system (Arz et al.,
2003; Waldmann et al., 2009; Vaks et al., 2010). The K1-2010 speleothem from
Kanaan Cave, Lebanon, partly fills the disparity in spatial data coverage in
the Levant, and may help understand the spatial climate heterogeneity, if
any, of the palaeoclimatic patterns.
(a) Location map of Kanaan Cave and the continental records in the
Levant. (a) Geological map of the Antelias region (western flank of central
Mount Lebanon; Dubertret, 1955). (b) Photo of K1-2010 stalagmite in the
Collapse Chamber. (c) Geomorphological section of Kanaan Cave showing the
location of the stalagmite K1-2010 (Nehme, 2013).
Location of Kanaan Cave
Kanaan Cave is located on the western flank of central Mount Lebanon, 15 km
northeast of Beirut at 33∘54′25 N, 35∘36′25 E. The
cave developed in the Middle Jurassic Kesrouane Formation, a thick
predominantly micritic limestone and dolomite sequence with an average
stratigraphic thickness of 1000 m (Fig. 2a). Being located only 2.5 km from
the Mediterranean coast and at just 98 m above sea level (a.s.l.), the cave
is strongly influenced by the maritime Mediterranean climate.
Kanaan Cave is a 162 m long relict conduit discovered during quarrying in
1997. A 23 cm long stalagmite, sample K1-2010 was collected from the top of
a fallen limestone block in the central part of the Collapse I chamber,
approximately 20 m from the (formerly closed) cave entrance (Fig. 2b–c).
The fallen block rests on an unknown thickness of sediment. The passage
height at this location is 2.4 m with approximately 50 m of limestone
overburden. Presently, the stalagmite receives no dripping water, although
some drip water occurs in other parts of the Collapse I chamber during
winter and spring seasons. The cave is generally dry during the summer
months. The air temperature in Collapse I chamber is 20 ∘C ± 1 ∘C.
Methods
The stalagmite (sample K1-2010) was cut along its growth axis after
retrieval from the cave, and polished using 120–4000 µm silicon
carbide (SiC) paper. Petrographic observations were performed with an
optical binocular microscope.
The first 10 U-series datings were carried out at the NERC Isotope
Geosciences Laboratory (NIGL), British Geological Survey, Keyworth, UK.
Seven new ages were recently completed by the NIGL geochemistry laboratory
and the Geochemistry Laboratory, Earth Science Department, University of
Melbourne, Australia. Powdered 100 to 400 mg calcite samples were collected
with a dental drill from 11 levels along the growth axis of the
speleothem, taking care to sample along growth horizons. Chemical separation
and purification of uranium and thorium were performed following the
procedures of Edwards et al. (1987) with modifications. Data were obtained
on a Thermo Neptune Plus multicollector inductively coupled plasma mass
spectrometer (MC-ICP-MS) following procedures modified from Anderson et al. (2008), Heiss et al. (2012), and Hellstrom (2006). Mass bias and SEM gain for
Th measurements were corrected using an in-house
229Th–230Th–232Th reference solution calibrated against CRM
112a. Quoted uncertainties for activity ratios, initial 234U /238U,
and ages include a ca. 0.2 % uncertainty calculated from the combined
236U /229Th tracer calibration uncertainty and measurement
reproducibility of reference materials (HU-1, CRM 112a, in-house Th
reference solution) as well as the measured isotope ratio uncertainty. Ages
are calculated from time of analysis (2014) and also in years before 1950
with an uncertainty at the 2σ level, typically of between 500 and
1000 years (see Table 1).
Data in bold calculated using average continental detritus U–Th composition: (230Th /238U) = 1.0 ± 50%,
(232Th /238U) = 1.2 ± 50%, (234U /238U) = 1 ± 50%. * Data in italics calculated using detritus U–Th composition of Kaufmann et al. (1998):
(230Th /238U) = 0.9732 ± 50%,
(232Th /238U) = 0.5407 ± 50%, (234U /238U) = 1 ± 50%. Underlined data are uncorrected activity
ratios.
Samples for δ13C and δ18O measurements were
drilled along the speleothem central axis using a 1 mm dental drill. Ethanol
was used to clean the speleothem surface and drill bit prior to sampling.
Sample resolution was 1 to 1.2 mm. A total of 206 samples were analysed
using the Nu Carb carbonate device coupled to a Nu Perspective MS at the
Vrije Universiteit Brussel with analytical uncertainties less than 0.1 %
(2 s) for oxygen and 0.05 % (2 s) for carbon. Isotopic equilibrium analyses
were carried out using six recent calcite samples collected in the cave and
Hendy tests (Hendy, 1971) were carried out at five different locations along
the speleothem growth axis. No evidence for severe out-of-equilibrium
deposition was detected along the growth axis of the stalagmite.
Three seepage water samples and three water pool samples from Kanaan Cave
were collected for δ18O measurements in hermetically sealed
glass bottles. Measurements were performed at the Vrije Universiteit Brussel
on a Picarro L2130-i analyser using the cavity ring-down spectroscopy (CRDS)
technique (Van Geldern and Barth Johannes, 2012). All values are reported
in per mill (‰) relative to Vienna Standard Mean Ocean
Water (V-SMOW2). Analytical uncertainties (2σ) were less than 0.10 ‰.
ResultsPetrography
The speleothem collected from Kanaan Cave is 23 cm long and up to 10 cm wide
(Fig. 2). In section it displays regular layers of dense calcite ranging in
colour from dark brown to light yellow with a regular thin (< 0.2 mm) lamination in places. The speleothem has two clearly defined growth
phases, characterized by an abrupt hiatus where the stalagmite was tilted
around 45∘ and then recommenced growing.
The lower segment (Segment 1) is 8.2 cm long and 8.5 cm wide (Fig. 3) and
displays a general growth axis tilted at a 45∘ angle (clockwise)
relative to upper segment. The regular deposition of translucent columnar
crystals is interrupted by clayey layers (discontinuities) mostly at 17 cm,
from 15.6 to 15.2 cm, and at 14.2 cm. Between 12.2 and 14.2 cm, the lamina in
the central axial part of the speleothem show continuous clear and
translucent layering, but which becomes increasingly clayey towards the
outer edge of the sample. The higher segment (Segment 2) is 12.3 cm long and
4–6 cm wide. At the base, the general growth axis is tilted at 16∘
(anticlockwise) to the azimuth axis, gradually becoming more vertical
towards the top. The general structure of this section is characterized by
uniform yellow translucent columnar crystals interrupted by marked opaque
yellow layers, at 9, 8, 5.6, 3.2, and 2.8 cm depth (from the top of the stalagmite).
Cut face of the K1-2010 speleothem and sketch showing the position
of the uranium series age data. In Segment 1, the dashed line indicates
detrital layers and U–Th shows many more uncertainties than those in the
Segment 2. The third age from the base of Segment 1 is an outlier.
Segment 1 is tilted from its initial position probably due to the suffosion
of clay deposits in the Collapse Chamber that caused the block on which the
speleothem grew to subside. Red lines indicate discontinuities.
Uranium series (U–Th) dating
A rectified age model is proposed here based on the new ages recently
completed: the stalagmite grew from 127.2 ± 1.3 (2σ) to
85.4 ± 0.8 ka (2σ). An extrapolated age of 83.1 ka for the top
of the stalagmite was calculated from the age–depth model in Fig. 4 obtained
using the P_Sequence function of the OxCal geochronology
application, which is based on Bayesian statistics (Bronk Ramsey, 2008). All
ages in Table 1 are calculated with two different possible detrital U–Th
compositions, as no data from Kanaan Cave are presently available to
better constrain the corrections. The first correction is the typical
continental detritus composition as used by Verheyden et al. (2008) and the
second is that used determined by Kauffman et al. (1998) for the Soreq caves
which might better reflect the prevalent detritus composition in a
carbonate-dominated terrain.
Basically the age uncertainties and 230Th /232Th activity ratios in
the data set are such that both options (i.e. Soreq Cave vs. average
continental detritus) result in statistically equivalent dates (i.e. Sample
10: 99.94 ± 0.69 ka calculated with the average continental detritus
and 99.40 ± 0.94 ka calculated using Soreq Cave detritus).
The greater number of disturbed ages in the lower segment of the stalagmite,
which has comparatively high initial thorium concentrations
(230Th /232Th activity ratios as low as 34), is most likely due to
contamination of the U–Th subsamples with organic material, or iron oxides
from mud layers that are common in this part of the record. The basal age of
223.2 ± 4.8 is clearly out of sequence probably due to accidental
inclusion of host rock in the analysed sample. Consequently, the oldest
valid U–Th date is 127.2 ± 1.3 ka from a sample located 7 mm above the
base of the stalagmite, and extrapolation of the age model places the
beginning of growth at ∼ 128.8 ka. However, as no other coeval
stalagmites from Kanaan Cave have yet been dated, it is unclear whether
the base of our record corresponds to the onset of the LIG optimum. In
general, U–Th dates from the upper segment of the stalagmite were more
consistent with only one out of seven dates (80.6 ± 0.5 ka) clearly
out of sequence.
Following the exclusion of obvious outliers, the remaining U–Th data set
showed a number of age reversals. For the purposes of age–depth modelling,
where age reversals were resolvable at the 3σ level, the younger date
was assumed to represent the correct age progression and the older dates
were excluded such as the basal age in the previous age model (Verheyden et
al., 2015). Age models obtained using linear interpolation, and the OxCal
package were statistically equivalent at the 95 % confidence level, with
the latter chosen as the basis for stable isotope proxy data interpretation,
owing to its more robust treatment of uncertainty propagation.
Modern cave water and calcite isotopic compositions
Recent cave water (a proxy for rainfall δ18O) sampled from the
cave shows an average δ18O value of -5.43 ± 0.06 ‰. δ18O and δD seepage water
values in Kanaan Cave falls on the Lebanese meteoric waterline (Saad et al.,
2000) indicating that no severe evaporation processes occur in the epikarst
before precipitating the speleothem (see Supplement). Recent calcite
analyses in the cave (soda straw, recent calcite deposition) display an
average δ13C value of -11.6 ‰ ± 0.4
and δ18O value of -4.9 ‰ ± 0.7 (see Supplement). The average δ18O value for the recent
calcite is close to the theoretical calcite precipitation value of
-4.4 ‰ (20 ∘C) – present temperature in
the cave – using the Kim and O'Neil (1997) equilibrium equation.
Oxygen and carbon isotope series
If precipitation occurs at isotopic equilibrium, the calcite δ18O should not show any significant enrichment along a single lamina
away from the growth axis and no covariation between δ18O and
δ13C should occur. As indicated by several of these so-called
Hendy tests (Hendy, 1971) performed along growth layers, no severe
out-of-equilibrium processes during precipitation of the calcite seem to
have occurred (see Supplement).
The δ18O values from K1-2010 (Fig. 4) ranged from -3.5 to -7.8 ‰, with an overall mean of -5.1 ‰.
Lower values (∼-7.5 ‰) are observed at
the basal part of the stalagmite. Values enrichment begin at ∼ 126 ka and increase rapidly to ∼-4.45 ‰
until ∼ 120 ka. High δ18O values (generally
between -4.4 and -4 ‰) are observed until the top of
the stalagmite at ∼ 84 ka, except for two periods with
relatively lower δ18O. From 102.8 to 100.8 ka (interpolated),
the δ18O values decrease from -4.6 to
-6.18 ‰ in ∼ 2.0 kyr. At ∼ 94
ka, a rapid decrease in δ18O values leads to a peak of
-5.5 ‰ at ∼ 92.3 ka (interpolated). The top
of the stalagmite at ∼ 84 ka exhibit the highest δ18O values of -3.5 ‰. The δ13C VPDB
values range between -10.0 and
-12.4 ‰ with an overall mean of
-11.3 ‰ as shown in Fig. 5. The δ13C curve
shows relatively minor variations. However, the most depleted values
(-12 ‰) are observed at the base of the speleothem, from
∼ 129 to ∼ 125.6 ka (interpolated), followed
by a δ13C enrichment of ∼ 2 ‰
from 125.6 (interpolated) to ∼ 122 ka and stays around
-11 ‰ between ∼ 120 and ∼ 110 ka. After ∼ 110 ka, generally lower δ13C
values prevail with a surprising stable period between ∼ 103
and ∼ 91 ka. From ∼ 91 to ∼ 87 ka, a 1.1 ‰ enrichment of carbon isotopic values leads to
highest δ13C values of the time series. Consequently, the
stalagmite shows a tripartite partition as shown in the δ18O
VPDB versus δ13C VPDB diagram (Fig. 6) with the base
featuring the most depleted δ18O and δ13C values
before ∼ 126 ka. A rapid shift towards higher isotopic values
between ∼ 126 and ∼ 120 ka and a third segment,
from ∼ 120 to ∼ 83 ka, show rather stable
δ13C and δ18O values except for the
93–87 ka period characterized by a change to lower isotopic values for oxygen and higher
values for carbon.
Growth rate of the stalagmite with respect to distance (in cm)
from the top, using OxCal Bayesian statistics model between two consecutive
dates except in the middle part where a discontinuity (hiatus) is
identified.
δ18O and δ13C profiles (values are in
‰ VPDB) of samples microdrilled along the growth axis of
the K1-2010 stalagmite (Kanaan Cave, Lebanon).
DiscussionIntegrated climatic interpretation of the speleothem proxies
Speleothem growth is conditioned by effective precipitation and CO2
concentration, controlled mainly by the bio-activity of the soil and
consequently by the temperature (Baker and Smart, 1995; Dreybrodt, 1988;
Genty et al., 2006). Therefore speleothem growth is typically associated
with warm and humid conditions with sufficient rainfall to maintain
drip-water flow, whereas low speleothem growth rates or hiatuses tend to
indicate cold or dry conditions (Bar-Matthews et al., 2003), or possibly
flooding. The lower part of the stalagmite contains several clayey layers
that may indicate either short dry periods or periods during which the
speleothem was covered with mud or muddy water (Fig. 3). The fact that apart
from these muddy layers the speleothem does not show any change in crystal
aspect or change in porosity suggests that these layers may be better
explained by sudden events perturbing slightly the speleothem deposition
rather than a significant increase in aridity or drop in temperature.
Previous studies in southern Europe (Drysdale et al., 2005; Zanchetta et
al., 2007) and in the eastern Levant (Bar-Matthews et al., 2003; Frumkin et
al., 2000; Verheyden et al., 2008) have shown that most of the carbon in
speleothem calcite is derived from soil CO2 (Genty et al., 2001). The
δ13C is thus most likely to be controlled by biogenic soil
CO2 productivity (Gascoyne, 1992; Hellstrom et al., 1998; Genty et al.,
2006) associated with vegetation density, which regulates soil CO2
content via root respiration, photosynthetic and microbial activity. The
changes in carbon isotopic composition (δ13C) of speleothems in
the Levant are thus linked to changes in precipitation with periods of low
rainfall inducing sparse vegetation and a lower contribution of “light”
organic carbon in the speleothem resulting in higher δ13C value
(Frumkin et al., 2000). The low values for δ13C in the K1-2010
around ∼ 128 ka are indicative of a 100 % C3 vegetation
profile, with relatively high soil productivity suggestive of rather mild and
humid conditions.
A discontinuity (D2) is observed in the first segment (Fig. 3) and is
estimated to occur between ∼110 and ∼103 ka by extrapolating the
growth rates of each segment towards the discontinuity (D2). This hiatus could
be of local origin as it is associated with a major change in the speleothem
orientation (Nehme et al., 2015). A striking decrease in the growth rate to
5 mm ka-1 before the speleothem tilted seems to start after 126 ka, before the
end of the LIG (Cheng et al., 2009). Additional U-series dates are necessary
to better constrain the age of the change in growth rate.
The middle part shows a higher growth rate (9 mm ka-1) from ∼103 to
∼99.1 ka during the ensuing interstadial (MIS 5c). A general decrease
in growth rate (5 to 7 mm kyr-1) followed from ∼99.1 to ∼83 ka
but with an unusual rapid increase in growth rate (13 mm ka-1) occurred from
∼86 to ∼84 ka during MIS 5b (Fig. 4). The carbon isotope signal
shifts slightly to more positive values around ∼126–121 ka and has the
most positive values after ∼92 ka, indicating a gradual degradation of
the soil coverage or change in vegetation type or density at the beginning
of MIS 5d.
Unravelling the factors controlling the δ18O signal in a
speleothem can be more complex (McDermott, 2004; Fairchild et al., 2006;
Lachniet, 2009). The pattern of δ18O changes in K1-2010
stalagmite is slightly different from the δ13C, particularly
the difference in the amplitude of changes between ∼126 and 120 ka,
and from 120 to 83 ka.
Speleothem δ18O is controlled by both the calcite precipitation
temperature (Kim and O'Neil, 1997) and seepage water δ18O
(Lachniet, 2009). The general consensus in recent years is that the
principal driver of speleothem δ18O variations through time is
change in rainfall δ18O (McDermott, 2004), which are forced by
(i) condensation temperatures, (ii) rainfall amount (Dansgaard, 1964); (iii)
shifts in vapour source δ18O, or (iv) different air-mass
trajectories (Rozanski et al., 1993). Until now, low speleothem δ18O values in the Levant region were associated with wetter conditions,
while high speleothem δ18O was generally ascribed to drier
periods with lower rainfall amounts (Bar-Matthews, 2014; Verheyden et al.,
2008). Important changes in δ18O may, however, also have been linked
to changes in the source of the water vapour and/or changes in storm tracks
(Frumkin et al., 1999; Kolodny et al., 2005; McGarry et al., 2004). From
∼ 126 to ∼ 120 ka, the abrupt
3.2 ‰ increase in δ18O values suggests an
important change to drier conditions. The growth rate of the stalagmite
gradually falls from a high rate (19 mm ka-1) between 126.7 ± 1.0 and
126.3 ± 0.9 ka, decreasing to 5 mm ka-1 between 126.3 ± 0.9 and
123.5 ± 1.6 ka, and to 3 mm ka-1 between 123.4 ± 1.6 and 117.7 ± 3.0 ka (Fig. 4). This gradual drop in growth rate most probably
indicates a change towards drier conditions in agreement with the increase
in δ18O values. Global sea levels reached 6 to 9 m above
present sea level during the LIG (Dutton and Lambeck, 2012), an elevation
peak that could not be responsible for the observed high amplitude of the
δ18O change in the K1 speleothem. Another mechanism is a change
in the composition and source of water vapour reaching the site. Studies of
the eastern (EM), central, and western Mediterranean marine core records show
evidence of reduced sea-surface δ18O during the onset of the
Sapropel 5 event of ∼ 2 ‰ (e.g. Kallel et
al., 1997, 2000; Emeis et al., 2003; Rohling et al., 2002; Scrivner et al.,
2004; Ziegler et al., 2010; Grant et al., 2012) and a recovery of the same
amount at the end of S5 deposition around ∼ 121 ka (Grant et
al., 2012), with a commensurate increase in the δ18O of the EM
water. Hence, a more 18O-enriched sea surface of ∼
2 ‰ at the end of the sapropel event would cause an
increase in vapour δ18O, leading to enrichment in the isotopic
composition of the recharge waters reaching the cave. In the Levant,
moisture source was interpreted as one of the drivers for the δ18O signal in speleothems from Soreq Cave (Bar-Matthews et al., 2003)
related to S5 (128–121 ka; Grant et al., 2012).
Oxygen versus carbon stable isotopic composition (values are in
‰ VPDB) of samples microdrilled along the growth axis
of the K1-2010 stalagmite (Kanaan Cave, Lebanon). The present-day δ18O value for the precipitated calcite was calculated using the Kim
and O'Neil (1997) equilibrium equation. The δ13C value was
obtained from the Holocene δ13C mean value of Jeita Cave
(Verheyden et al., 2008). This cave, located just 20 km to the north, has a
very similar climate, vegetation geology, soil type, and altitude (98 m a.s.l.)
to Kanaan Cave.
After ∼ 120 ka, the δ18O increased to an average
of ∼-4.3 ‰, suggesting less depleted
precipitation was reaching the cave until ∼ 84 ka. This
long-term δ18O enrichment, interrupted by a short and moderate
δ18O decrease during the S4 event, marks the Northern Hemisphere
glacial inception (Fig. 6). This increase in δ18O is driven by
several mechanisms. Once cause, the “ice volume effect”, can lead to a higher
sea water δ18O by 1.1 ‰ during glacial
periods together with an increase in δ18O of speleothem calcite
due to drop in temperature of up to ∼ 8 ∘C (Frumkin
et al., 1999; Bar-Matthews et al., 2003; Kolodny et al., 2005; McGarry et
al., 2004). However, the change in the K1 speleothem δ18O
records occurs after the gradual variation in the global interglacial–glacial changes at
Termination II, suggesting a stronger influence of other mechanisms. A second
possible driver for increased δ18O is related to changes in
wind direction, with more continental trajectories leading to more enriched
δ18O water vapour reaching the cave. In the southern Levant, Frumkin
et al. (1999) and Kolodny et al. (2005) related δ18O signal
increase during glacial periods to a southward migration of the westerlies
associated with the high-pressure zone over the northern European ice sheet
and thus pushing wind trajectories further south over North Africa. The
growth rate (Fig. 3) of the stalagmite after ∼ 120 ka is the
lowest of the entire profile (between 2 and 7 mm ka-1) except for the
periods between 84.8 ± 1.1 and 85.9 ± 1.1 ka and between 102 ± 1.1 and 99.3 ± 0.9 ka. The first period has a growth rate
of 13 mm ka-1, indicating a wet pulse that could correspond to the
pre-sapropel 3 event (Ziegler et al., 2010). The latter period has a moderate growth
rate of 9 mm ka-1 indicating a wet pulse, which coincides with the S4 event.
The discontinuity (D2), between ∼ 110.6 and ∼ 103.6 ka, is probably linked to local factors such as change in the
percolation route or the tilting of the stalagmite's axis due to the floor
suffusion beneath the block on which the speleothem grew.
Left panel: Kanaan Cave δ18O and δ13C profiles
compared to continental records in the Levant. From north to south of the Levant:
(a) Yammouneh AP %, north Lebanon (Gasse et al., 2015); (b) Kanaan carbon
and oxygen isotopic profile (this study); (c) Peqiin Cave (Bar-Matthews et
al., 2003); (d) Soreq Cave (Grant et al., 2012); (e) Tzavoa Cave (Vaks et
al., 2006); and (f) lake Samra palaeolevels in the Dead Sea basin (Waldmann et
al., 2009). Right panel: Kanaan Cave δ18O profile compared to global and
regional records in the eastern Mediterranean Basin: (g) summer insolation
at 30∘ N and orbital eccentricity forcing (Berger and Loutre,
1991); (h) NGRIP-NEEM, indicating the volume of the Arctic ice sheet (NGRIP
Members, 2004; + NEEM community members, 2013); (i) eastern Mediterranean
δ18OG.ruber in core LC21 (Grant et al., 2012);
(j) Mediterranean sapropel events (Ziegler et al., 2010) and the Nile flooding
event (Scrivner et al., 2004); and (l) EMS Mediterranean δ18OG.ruber in ODP Site 967 and in MD 70-41 site resampled at
1 kyr intervals (Emeis et al., 2003).
Palaeoclimate variability in MIS 5An “early humid LIG”
Speleothem oxygen, carbon, and growth proxies from sample K1-2010 indicate an
initial relatively warm and humid period at ∼ 129 ka – the
beginning of speleothem deposition – which extended until ∼
126 ka (Fig. 7). This early humid LIG matches the timing of the eastern
Mediterranean Sea S5 event (Ziegler at al., 2010; Grant et al.,
2012) with high summer insolation (Berger and Loutre, 1991). In southern
Europe, an early commencement of full interglacial conditions was dated at
129 ± 1 ka in Corchia Cave speleothems (Drysdale et al., 2005). In the
northern Levant, the pollen records in Yammouneh palaeolake demonstrate the
presence of temperate oaks during the early LIG (Develle et al., 2011),
indicating sufficient humidity to enable forests to develop. More efficient
moisture retention together with developed forest landscapes and intense
groundwater circulation in northern Lebanon prevailed during the LIG. These
warm and wet conditions are in agreement with similar periods identified in
the Lake Van lacustrine sequence (Litt et al., 2014; Shtokhete et al., 2014)
in northeastern Turkey and with speleothem proxies from the Soreq and Peqiin
caves (Ayalon et al., 2002; Bar-Matthews et al., 2003) in southwestern
Israel.
The 126 ka change
The pattern of δ18O depletion from sample K1-2010 records a
remarkable change between 126.3 ± 0.9 and ∼ 120.3 ka
(interpolated) along with an unstable enrichment pattern of the δ13C and the δ18O (Fig. 5). However, the poor
chronological resolution of this part of the K1-2010 speleothem record
precludes the identification of any seasonality pattern at the end of the
LIG, as seen in the Yammouneh lacustrine record in northern Lebanon (Develle
et al., 2011; Gasse et al., 2015).
The K1-2010 δ18O profile undergoes a dramatic change around
∼ 126 ka, the timing of which is very close to the onset of
the isotopic enrichment of the water source in the eastern Mediterranean Sea
during the S5 event (∼ 128–121 ka). The onset of the δ18O enrichment in the K1-2010 isotopic record coincides with the onset
of the δ18OG.ruber enrichment (Fig. 7) in core LC21 (Grant
et al., 2012) and at ODP Site 967 (Emeis et al., 2003). Despite differences
in dating resolution between marine core records and speleothems, the shift
in K1-2010 δ18O values around ∼ 126 ka
demonstrates a major source-driven change during the eastern Mediterranean
S5 event. Several studies (Rohling et al., 2002, 2015a; Schmiedl et al.,
2003; Scrivner et al., 2004) suggest a coincidence between cooling and
enhanced aridity around the Mediterranean, and the interruption of the
insolation-driven monsoon maximum for a millennial-scale episode during the
last interglacial S5. Schmiedl et al. (2003) argue that this
episode marked the onset of a regional climate deterioration following the
peak (early S5) of the last interglacial. In that case, this regional
climate deterioration began at ∼ 126 ka ( Fig. 7), using the
S5 timing of Grant et al. (2012) and with the assumed linear sedimentation
rate through S5 (Rohling et al., 2002). The KI-2010 isotopic profile
confirms this and provides a precise chronology of the change, taking place
between 126.3 ± 0.9 ka and ∼ 120.3 ka (interpolated).
However, the amplitude of the δ18O enrichment in the K1-2010
stalagmite from 126 to 120 ka totals ∼ 3.2 ‰ and is much higher than the amplitude of the
δ18OG.ruber enrichment (∼ 2 ‰) in the eastern Mediterranean sea (Grant et al.,
2012). This would be explained by Sapropel events in the EMS and their
derivative processes during the S5 event (Ziegler et al., 2010): the source effect
is thus a major driver for the δ18O values change in continental
records, but other derivative factors of the S5 event contributed in the
δ18O change in K1-2010 record such as the rainfall amount, the
temperature, or changes in the wind trajectories.
With the additional U–Th datings and new records of Soreq Cave (Grant et al.,
2012), the K1-2010 δ18O profile indicates that this major
change occurred in phase with other continental records in the Levant
region, moving the interpretation based on previous age model (Verheyden et
al., 2015). The δ18O and δ13C change in the K1-2010
profiles lasted 6000 years, started gradually, and then continued more
rapidly, ending at ∼ 120.3 ka (interpolated). The initial
pattern of the change from ∼ 126 to ∼ 122 ka
suggests more gradual δ18O enrichment than the change in the
Soreq Cave δ18O records. Nonetheless, the rapid pattern of the
δ18O changes well recorded by the Soreq Cave record in that
period could not be observed in the Kanaan Cave record due to the poor
resolution of this part of the K1 speleothem with the occurrence of short
hiatuses (mud layers). A similar gradual variation but over a larger timescale was demonstrated in the Yammouneh palaeovegetation signal, where the
transition seems to be more progressive than in other eastern Mediterranean
records. In the southern Levant, the oxygen and carbon isotopic record in the Peqiin
and Soreq caves suggest an abrupt but later enrichment signal around
∼ 118 ka (Bar-Matthews et al., 2003). This change was shifted
to ∼ 120.5 ka (Grant et al., 2012) using a more refined U–Th
chronology (Fig. 7).
The glacial inception
After ∼ 120.3 ka, a more enriched δ18O profile
indicates the end of warm and wet conditions of the LIG. The onset of
glacial conditions as indicated in several continental records in the
eastern Mediterranean (Fig. 7) shows gradual climate deterioration into the
glacial inception period before MIS 4. The isotopic response of K1-2010
to the glacial inception is recorded synchronously at ∼ 120 ka
in both δ18O and δ13C signals, but while the
δ18O decreases rapidly along with a shift to a moderate growth
rate, especially in response to the wet pulses during the S4 event, the
δ13C shows a more gradual evolution. This can be explained by
the fact that a rainfall- and mostly source-driven δ18O signal
is rapidly transmitted to K1-2010 speleothem, whereas the inertia and
gradual change in the δ13C signal reflect a long-term
deterioration of the soil and biopedological activity above the cave. On a
regional scale, the Yammouneh palaeovegetation signal indicates expanded
steppic vegetation cover after ∼ 120 ka (Develle et al., 2011).
In the southern Levant, a gradual δ13C and δ18O
enrichment, except for the wet pulses during the S4 and S3 events, until the
end of MIS 5 indicates a general climate degradation that could be
related to less rainfall derived from the Mediterranean moisture source
(Ayalon et al., 2002; Bar-Matthews et al., 2003) or to changes in wind
circulation pattern (Kolodny et al., 2005; Lisker et al., 2010). Further
south in the Negev region, a different climatic regime from the northern
Levant is recorded from speleothems and lacustrine records. Speleothem
growth rates decreased after MIS 5c (Vaks et al., 2006), with less rainfall
from the Mediterranean Sea reaching Tzavoa Cave (northern Negev). Speleothem
records from caves located further south in the Negev Desert (Vaks et al.,
2010) along with the Mudawara palaeolake records in southern Jordan showed a
wet pulse during MIS 5a, related more to rainfall originating from the
Indian monsoon (Petit-Maire et al., 2010). Moreover, Lake Samra records in
the DSB are less out of phase with Levantine records further
north than suggested for the last 20 kyr (Cheng et al., 2015). The
DSB records, recently investigated with a higher chronological resolution
(Neugebauer et al., 2015) than previous studies (Waldmann et al., 2009),
show minor high levels during MIS 5c and 5a. These wet pulses indicate
though wet periods but with smaller amplitude than the wet phase in the
northern Levant. The climate picture of the DSB during the glacial
inception is related probably to local factors influenced by the Judean rain
shadow (Vaks et al., 2006, 2013) and, together with other continental records
further south, invokes climatic variations driven by the monsoon system
(Torfstein et al., 2015) and its boundary shifts (Parton et al., 2015;
Bar-Mathews, 2014) or by the North Atlantic and Mediterranean climates
(Neugebauer et al., 2015).
Conclusions
A dated MIS 5 stalagmite record (129–84 ka) from Kanaan Cave, Lebanon,
demonstrates the potential of stalagmite records for palaeoclimate
reconstruction in the northern Levant. The K1-2010 model age coupled with
growth rates and isotopic data provide a more precise record of the climatic
changes that occurred during the last interglacial and on into the glacial
inception period.
The K1-2010 speleothem record indicate a very wet early LIG and during the
LIG optimum at the global scale, and is in agreement with warm and humid
conditions demonstrated in other speleothem and lacustrine records from the
Mediterranean. The K1-2010 isotope record and growth rate curves clearly
demonstrate an important change from 126.3 ± 0.9 to 120.3 ka
(interpolated). The change seems to be driven mainly by a “source” effect,
reflecting the δ18O Mediterranean Sea surface water composition
and the EM isotopic increase at ∼ 126 ka during the S5 event.
Other factors such as the rainfall amount, the temperature or the wind
trajectories might have contributed as a second-order factor to the δ18O change from 126 to 120 ka. This change sets the onset of the
regional climate deterioration following the peak (early S5) of the last
interglacial over the Levant region. However, the climatic change as
recorded in the K1-2010 isotopic record could be more gradual than the
changes identified in the Soreq and Peqiin speleothem records.
After ∼ 120 ka, enriched oxygen and carbon profiles in K1-2010
document the end of the LIG humid phase. The change in isotopic composition
from 122 to 120 ka is driven by a reduction in rainfall originating from the
Mediterranean Sea, coupled with a long-term change in the δ18O
composition of the EM surface waters. The onset of glacial inception
conditions, as indicated in several continental records in the Levant, is
signified by a gradual climatic deterioration until the full glacial
conditions of MIS 4. A short, wet phase (∼ 103–100 ka) at
the end of the S4 event is indicated by increased water circulation into
Kanaan Cave causing faster speleothem growth rates, sediment flushing,
subsidence, and speleothem tilting. The climatic scheme suggested from
K1-2010 isotopic profiles and growth rates is in overall agreement with
Yammouneh palaeolake records in northern Lebanon, and with the Soreq and
Peqiin speleothem records. However, the K1-2010 record shows different
amplitude patterns with continental records located further south, although
it does not show a clear out-of-phase climate variability during MIS 5 as
demonstrated for the last 20 000 years by the Jeita speleothem record (Cheng
et al., 2015).
The Supplement related to this article is available online at doi:10.5194/cp-11-1785-2015-supplement.
Acknowledgements
This study was funded by the mobility fellowship programme of the Belgian
Federal Scientific Policy (BELSPO), co-funded by the Marie Curie Actions of
the European Commission. We acknowledge EDYTEM Laboratory (UMR-5204 CNRS)
and Saint-Joseph University for making stalagmites of Kanaan Cave available
for analyses during this study. We would like to thank the support of ALES
(Association Libanaise d'Etudes Spéléologiques) members who
accompanied us during field trips. Farrant and Noble publish with the
approval of the Executive Director, British Geological Survey. We thank
Thomas Goovaerts for sampling preparation, Daniel Condon for assisting with the uranium series analyses and Kevin De Bont for assisting in water analyses. We also thank the anonymous reviewers
for their constructive comments and reviews.
Edited by: D. Fleitmann
References
Andersen, M. B., Stirling, C. H., Potter, E. K., Halliday, A. N., Blake, S. G.,
McCulloch, M. T., Ayling, B. F. and O'Leary, M.: High-precision U-series
measurements of more than 500 000 year old fossil corals, Earth Planet. Sc.
Lett., 265, 229–245, 2008.
Arz, H. W., Lamy, F., Patzold, J., Muller, P. J., and Prins, M.: Mediterranean
moisture source for an early-Holocene humid period in the northern Red Sea,
Science, 300, 118–121, 2003.
Ayalon, A., Bar-Matthews, M., and Kaufman, A.: Climatic conditions during
marine isotopic stage 6 in the Eastern Mediterranean region as evident from
the isotopic composition of speleothems: Soreq Cave, Israel, Geology, 30,
303–306, 2002.
Ayalon, A., Bar-Matthews, M., Frumkin, A., and Matthews, A.,: Last Glacial
warm events on Mount Hermon: the southern extension of the Alpine karst
range in the east Mediterranean, Quaternary Sci. Rev., 59, 43–56, 2013.
Baker, A. and Smart, P. L.: Recent flowstone growth rates: field measurements
in comparison to theoretical predictions, Chem. Geol., 122, 121–128, 1995.
Bar-Matthews, M.: History of Water in the Middle East and North Africa, in:
Treatise on Geochemistry, edited by: Holland H. D. and Turekian K. K., Second Edition,
Oxford, Elsevier, 109–128, 2014.
Bar-Matthews, M., Ayalon, A., Kaufman, A., and Wasserburg, G. J.: The Eastern
Mediterranean paleoclimate as a reflection of regional events: Soreq Cave,
Israel, Earth Planet. Sc. Lett., 166, 85–95, 1999.
Bar-Matthews, M., Ayalon, A., and Kaufman, A.: Timing and hydrological
conditions of Sapropel events in the Eastern Mediterranean, as evident from
speleothems, Soreq Cave, Israel, Chem. Geol., 169, 145–156, 2000.
Bar-Matthews, M., Ayalon, A., Gilmour, M., Matthews, M., and Hawkesworth, C.:
Sea-land isotopic relationships from planktonic foraminifera and speleothems
in the Eastern Mediterranean region and their implications for paleorainfall
during interglacial interval,
Geochim. Cosmochim. Ac., 67, 3181–3199, 2003.
Bronk Ramsey, C.: Deposition models for chronological records, Quaternary
Sci. Rev., 27, 42–60, 2008.
Berger, A. and Loutre, M. F.: Insolation values for the climate of the last
10 million years, Quaternary Sci. Rev., 10, 297–317, 1991.
Cheddadi, R. and Rossignol-Strick, M.: Eastern Mediterranean Quaternary
paleoclimates from pollen and isotope records of marine cores in the Nile
cone area, Paleoceanography, 10, 291–300, 1995.
Cheng, H., Edwards, R. L., Broecker, W. S., Denton, G. H., Kong, X., Wang, Y.,
Zhang, R., and Wang, X.: Ice age terminations, Science, 326, 248–252, 2009.
Cheng, H., Sinha, A., Verheyden, S., Nader, F. H., Li, X. L., Zhang, P. Z., Yin, J. J.,
Yi, L., Peng, Y. B., Rao, Z. G., Ning Y. F., and Edwards R. L.: The climate variability in northern Levant over the
past 20 000 years, Geophys. Res. Lett., 42, 8641–8650, 2015.
Cuffey, K. M. and Marshall, S. J.: Substantial contribution to sea-level rise
during the last interglacial from the Greenland ice sheet, Nature, 404,
591–594, 2000.Dansgaard, W.: Stable isotopes in precipitation, Tellus, 16, 436–468, 10.1111/j.2153-3490.1964.tb00181, 1964.
Develle, A. L., Gasse, F., Vidal, L., Williamson, D., Demory, F., Van Campo,
E., Ghaleb, B., and Thouveny, N.: A 250 ka sedimentary record from a small
karstic lake in the Northern Levant (Yammoûneh, Lebanon): Paleoclimatic
implications, Palaeogeogr. Palaeoecol., 305,
10–27, 2011.
Dreybrodt, W.: Processes in karst systems, Springer-Verlag, New York, 288 pp., 1988.Drysdale, R., Zanchetta, G., Hellstrom, J., Fallick, A., and Zhao, J.-X.:
Stalagmite evidence for the onset of the Last Interglacial in southern
Europe at 129 ± 1 ka, Geophys. Res. Lett., 32, L24708,
2005.
Drysdale, R., Hellstrom, J., Zanchetta, G., Fallick A. E., Sánchez
Goñi, M. F., Couchoud I., McDonald J., Maas, R., Lohmann, G., and Isola I.:
Evidence for obliquity forcing of glacial
Termination II, Science, 325, 1527–1531, 2009.Drysdale, R. N., Zanchetta, G., Hellstrom, J. C., Fallick, A. E., McDonald, J.,
and Cartwright, I.: Stalagmite evidence for the precise timing of North
Atlantic cold events during the early last glacial, Geology, 35–1, 77–80,
doi:10.1130/G23161A.1,
2007.
Dutton, A. and Lambeck, K.: Ice volume and sea level during the last
interglacial, Science, 337, 216–219, 2012.Edwards, R. L., Chen, J. H., Ku, T. L., and Wasserburg, G. J.: Precise timing of
the last interglacial period from mass-spectrometric determination of
230Th in corals, Science, 236, 1547–1553, 1987.Emeis K. C., Schulz H., Struck U., Rossignol-Strick M., Erlenkeuser H.,
Howell M. W., Kroon D., Mackensen A., Ishizuka S., Oba T., Sakamoto T., and
Koizumi I.: Eastern Mediterranean surface water temperatures and δ18O during deposition of sapropels in the late Quaternary,
Paleoceanography, 18, 1005–1029, 2003.
Emiliani, C.: Pleistocene temperatures, J. Geol., 63, 538–578, 1955.
Enzel, Y., Amit, R., Dayan, U., Crouvi, O., Kahana R., Ziv, B., and Sharon D.: The
climatic and physiographic controls of the eastern Mediterranean over the
late Pleistocene climates in the southern Levant and its neighboring
deserts, Global Planet. Change, 60, 165–192, 2008.
Fairchild, I. J., Smith, C. L., Baker, A., Fuller, L., Spötl, C., Mattey,
D., and McDermott, F.: Modification and preservation of environmental
signals in speleothems, Earth Sci. Rev., 75, 105–153, 2006.
Frumkin, A., Ford, D. C., and Schwarcz, H.P .: Continental oxygen isotopic
record of the last 170 000 years in Jerusalem, Quatern. Res., 51,
317–327, 1999.
Frumkin, A., Ford, D. C., and Schwarcz, H.: Paleoclimate and vegetation of the
Last Glacial cycles in Jerusalem from a speleothem record, Global
Biogeochem. Cy., 14, 863–870, 2000.
Gascoyne, M.: Palaeoclimate
determination from cave calcite deposits, Quaternary Sci. Rev., 11,
609–632, 1992.Gasse, F., Vidal, L., Develle, A.-L., and Van Campo, E.: Hydrological variability in the Northern Levant: a 250 ka
multi-proxy record from the Yammoûneh (Lebanon) sedimentary sequence, Clim. Past, 7, 1261–1284, 10.5194/cp-7-1261-2011, 2011.
Gasse, F., Vidal L., Van Campo, E., Demory, F., Develle, A.-L., Tachikawa,
K., Elias, A., Bard, E., Garcia, M., Sonzogni., C., and Thouveny, N.:
Hydroclimatic changes in northern Levant over the past 400 000 years,
Quaternary Sci. Rev., 111, 1–8, 2015.
Genty, D., Baker, A., and Vokal, B.: Intra- and inter-annual growth rate of
modern
stalagmites, Chem. Geol., 176, 191–212, 2001.
Genty, D., Blamart, D., Ouahdi, R., Gilmour, M., Baker, A., Jouzel, J., and
Van-Exter, S.: Precise dating of Dansgaard-Oeschger climate oscillations in
western Europe from stalagmite data, Nature, 421, 833–837, 2003.Genty, D., Blamart, D., Ghaleb, B., Plagnes, V., Causse, C.h., Bakalowicz,
M., Zouari, K., Chkir, N., Hellstrom, J., Wainer, K., and Bourges, F.:
Timing and dynamics of the last deglaciation from European and North African
d 13C stalagmite profiles–comparison with Chinese and South Hemisphere
stalagmites, Quaternary Sci. Rev., 25, 2118–2142, 2006.
Grant, K. M., Rohling, E. J., Bar-Matthews, M., Ayalon, A., Medina-Elizalde,
M., Bronk Ramsey, C., Satow, C., and Roberts, A. P.: Rapid coupling between
ice volume and polar temperature over the past 150 kyr, Nature 491,
744–747, 2012.Hellstrom, J.: U–Th dating of speleothems with high initial 230Th
using stratigraphical constraint, Quat. Geochron., 1, 289–295, 2006.
Hellstrom, J., McCulloch, M., and Stone, J.: A detailed 31 000-year record
of climate and vegetation change, from the isotope geochemistry of two New
Zealand speleothems, Quaternary Res., 50, 167–178, 1998.Heiss, J., Condon, D. J., McLean, N., and Noble, S. R.: 238U/235U
systematics in terrestrial uranium-bearing minerals, Science, 335,
1610–1614, 2012.
Hendy, C. H.: The isotopic geochemistry of speleothems – I., The calculation
of the effects of different modes of formation on the isotopic composition
of speleothems and their applicability as palaeoclimatic indicators, Geochim. Cosmochim. Ac., 35, 801–824, 1971.
Kallel, N., Duplessy, J.-C., Labeyrie, L., Fontugne, M., Paterne, M., and Montacer, M.:
Mediterranean pluvial periods and sapropel formation during the last 200 000
years, Palaeogeogr. Palaeoecol., 157, 45–58, 2000.
Kallel, N., Paterne, M., Duplessy, J.-C., Vergnaud-Grazzini, C., Pujol, C.,
Labeyrie, L., Arnold, M., Fontugne, M., and Pierre, C.: Enhanced rainfall in
the Mediterranean region during the last sapropel event, Oceanol. Ac., 20,
697–712, 1997.
Kaufman, A., Wasserburg, G. J., Porcelli, D., Bar-Matthews, M., Ayalon,
A., and Halicz, L.: U-Th isotope systematics from the Soreq
Cave Israel and climatic correlations, Earth Planet. Sci. Lett., 156, 141–155,
1998.
Kim, S. T. and O'Neil, J. R.: Equilibrium and nonequilibrium oxygen isotope
effects in synthetic carbonates, Geochim. Cosmochim. Ac., 61–16, 3461–3475,
1997.
Kopp, R. E., Simons, F. J., Mitrovica, J. X., Maloof, A. C., and Oppenheimer,
M.: Probabilistic
assessment of sea level during the last interglacial stage, Nature, 462,
863–867, 2009.
Kolodny, Y., Stein, M., and Machlus, M.: Sea-rain-lake relation in the Last
Glacial East Mediterranean revealed by d18O-d13C in Lake Lisan aragonites,
Geochim. Cosmochim. Ac., 69, 4055–4060, 2005.
Lachniet, M. S.: Climatic and environmental controls on speleothem
oxygenisotope values, Quaternary Sci. Rev., 28, 412–432, 2009.
Lisker, S., Vaks, A., and Bar-Matthews, M.: Late Pleistocene palaeoclimatic
and palaeoenvironmental reconstruction of the Dead Sea area (Israel), based
on speleothems and cave stromatolites, Quaternary Sci. Rev., 29, 1201–1211,
2010.
Litt, T., Pickarski, N., Heumann, G., Stockhecke, M., and Tzedakis, P. C.: A
600 000 year long continental pollen record from Lake Van, eastern Anatoloia
(Turkey), Quaternary Sci. Rev., 104, 30–41, 2014.
Lourens, L. J., Antonarakou, A., Hilgren, F. J., Van Hoof, A. A. M.,
Vergnaud-Grazzini, C., and Zachariasse W. J.: Evaluation of the
Plio-Pleistocene astronomical timescale, Paleoceanography, 11, 391–413,
1996.
McDermott, F.: Paleo-climate reconstruction from stable isotope variations
in speleothems: a review, Quaternary Sci. Rev., 23, 901–918, 2004.
McGarry, S., Bar-Matthews, M., Matthews, A., Vaks, A., Schilman, B., and Ayalon, A.: Constraints on hydrological and paleotemperature variations in the
Eastern Mediterranean region in the last 140 ka given by thedD values of speleothem fluid inclusions, Quaternary Sci. Rev., 23,
919–934, 2004.
Moller, T., Schultz, H., Hamann, Y., Dellwig, O., and Kucera, M.:
Sedimentology and geochemistry of an exceptionally preserved last
interglacial sapropel S5 in the Levantine Basin (Mediterranean Sea), Mar.
Geol., 291–294, 34–48, 2012.
NEEM community members: Eemian interglacial reconstructed from a Greenland
folded ice core, Nature 493, 489–494, 2013.
Nehme, C., Verheyden, S., Noble, S., Farrant, A., and Delannoy, J. J.: Contribution of
an accurate growth rate reconstruction of a stalagmite from the Kanaan
Cave-Lebanon to the understanding of humidity variations in the Levant
during the MIS 5, Geol. Belg., 18, 2–4, 102–108, 2015.Neugebauer, I., Schwab, M. J., Waldmann, N. D., Tjallingii, R., Frank, U., Hadzhiivanova, E., Naumann, R., Taha, N., Agnon, A.,
Enzel, Y., and Brauer, A.: Hydroclimatic variability in the Levant during the early last glacial (∼ 117–75 ka) derived from micro-facies
analyses of deep Dead Sea sediments, Clim. Past Discuss., 11, 3625–3663, 10.5194/cpd-11-3625-2015,
2015.
North Greenland Ice Core Project members: High-resolution climate record of
Northern Hemisphere climate extending into the Last Interglacial period,
Nature, 431, 147–151, 2004.
Otto-Bliesner, B. L., Rosenbloom, N., Stone, E. J., McKay, N. P., Lunt, D. J.,
Brady, E. C., and Overpeck, J. T.: How warm was the Last Interglacial? New
model-data comparisons, Philos. T. R. Soc. A,
371,
1–20, 2013.
Parton, A., White, T. S., Parker, A. G., Breeze, P. S., Jennings, R., Groucutt,
H. S., and Petraglia, M. D.: Orbital-scale climate variability in Arabia as a
potential motor for human dispersals, Quaternary Int.,
382, 82–97, 2015.Petit-Maire, N., Carbonel, P., Reyss, J.L., Sanlaville, P., Abed, A.,
Bourrouilh, R., Fontugne,
M., and Yasin, S.: A vast Eemian palaeolake in Southern Jordan
(29∘ N), Global Planet. Change, 2,
72, 368–373, 2010.
Republic of Lebanon: Policy Note on Irrigation Sector Sustainability, Report
No. 28766–LE, the World Bank, Middle-East and North Africa Region, 2003.
Rohling, E. J., Cane, T. R., Cooke, S., Sprovieri, M., Bouloubassi, I., Emeis,
K. C., Schiebel, R., Kroon, D., Jorissen, F. J., Lorre, A., and Kemp, A. E. S.:
African monsoon variability during the previous interglacial maximum, Earth
Planet Sci. Lett., 202, 61–75, 2002.
Rohling, E. J., Sprovieri, M., Cane, T. R., Casford, J. S. L., Cooke, S., Bouloubassi, I., Emeis, K. C.,
Schiebel, R., Hayes, A., Jorissen, F. J., and Kroon, D.: Reconstructing past planktic foraminiferal habitats using stable isotope data: a case history for Mediterranean
sapropel S5, Mar. Micropaleontol., 50, 89–123, 2004.
Rohling, E. J., Sprovieri, M., Cane, T., Casford, J. S. L., Cooke, S.,
Bouloubassi I., Emeis K. C., Schiebel R., Rogerson M., Hayes A., Jorissen
F. J., and Kroon D.: Reconstructing past planktic foraminiferal habitats using
stable isotope data: a case history for Mediterranean sapropel S5, Mar. Micropaleontol., 50, 89–123,
2015a.
Rohling, E. J., Marino, G., and Grant, K. M.: Mediterranean climate and
oceanography, and the periodic development of anoxic events (sapropels),
Earth Sci. Rev., 143, 62–97, 2015b.
Rossignol-Strick, M. and Paterne, M.: The Holocene climatic optimum and
pollen records of sapropel 1 in the Eastern Mediterranean, 9000–6000 BP,
Quaternary Sci. Rev., 18, 515–530, 1999.
Rozanski, K., Araguas, L., and Gonfiantini, R.: Isotopic patterns in modern
global precipitation, in: Climate Change in Continental Isotopic Record,
Geophysical Monograph
Series, Washington DC, AGU, 78, 1–37, 1993.
Saad, Z., Slim, K., Ghaddar, A., Nasreddine, M., and Kattan, Z., Composition
chimique des eaux de pluie du Liban; Chemical composition of rain water in
Lebanon, Journal Europeen d'Hydrologie, 31–32, 105–120, 2000.
Saaroni, H., Ziv, B., Bitan, A., and Alpert, P.: Easterly wind storms over
Israel, Theor. Appl. Climatol., 59, 61–77, 1998.
Schmiedl, G., Mitschele, A., Beck, S., Emeis, K. C., Hemleben, C., Schultz,
H., Sperling, M., and Weldeab, S.: Benthic foraminiferal record of ecosystem
variability in the eastern Mediterranean Sea during times of sapropel S5 and
S6 deposition, Palaeogeogr. Palaeoecol., 190, 139–164, 2003.
Scrivner, A. E., Vance, D., and Rohling, E. J.: New neodymium isotope data
quantify Nile involvement in Mediterranean anoxic episodes, Geology, 32,
565–568, 2004.
Shackleton, N. J., Chapman, M., Sanchez Goni, M. F., Pailler, D., and
Lancelot, Y.: The classic marine isotope substage 5e, Quaternary Res., 58,
14–16, 2002.
Shtokhete, M., Sturm, M., Brunner, I., Schmincke, H.-U., Sumita, M., Kipfer,
R., Cukur, D., Kwiecien, O., and Anselmetti, F.: Sedimentary evolution and
environmental history of Lake Van (Turkey) over the past 600 000 years,
Sedimentology, 61, 1830–1861, 2014.
Torfstein A., Goldstein, S. L., Kushnir, Y., Enzel, Y., Haug, G., and Stein, M.:
Dead Sea drawdown and monsoonal impacts in the Levant during the last
interglacial, Earth Planet. Sci. Lett., 412, 235–244, 2015.
Vaks, A., Bar-Matthews, M., Ayalon, A., Schilman, B., Gilmour, M.,
Hawkesworth C. J., Frumkin A., Kaufman A., and Matthews A.: Paleoclimate
reconstruction based on the timing of speleothem growth, oxygen and carbon
isotope composition from a cave located in the “rain shadow”, Israel,
Quaternary Res., 59, 182–193, 2003.
Vaks, A., Bar-Matthews, M., Ayalon, A., Matthews, A., Frumkin, A., Dayan,
U., Halicz, L., Almogi-Labin, A., and Schilman, B.: Paleoclimate and
location of the border between Mediterranean climate region and the
Saharo-Arabian desert as revealed by speleothems from the northern Negev
Desert, Israel, Earth Planet. Sci. Lett., 249, 384–399, 2006.
Vaks, A., Bar-Matthews, M., Matthews A., Ayalon, A,. and Frumkin, A.:
Middle-Late Quaternary paleoclimate of northern margins of the
Saharan-Arabian Desert: reconstruction
from speleothems of Negev Desert, Israel, Quaternary Sci. Rev., 29,
2647–2662, 2013.
Van Geldern R. and Barth Johannes A. C.: Optimization of instrument setup and
post-run corrections for oxygen and hydrogen stable isotope measurements of
water by isotope ratio infrared spectroscopy (IRIS), Limnol. Oceanogr.-Methods, 10, 1024–1036, 2012.Verheyden, S., Nader, F. H., Cheng, H. J., Edwards, L. R., and Swennen, R.:
Paleoclimate reconstruction in the Levant region from the geochemistry of a
Holocene stalagmite from the Jeita cave, Lebanon, Quaternary Res., 70,
368–381, 2008.
Verheyden S., Nehme C., Nader F. H., Farrant A. R., Cheng H., Noble S. R., Sahy
D., Edwards R. L., Swennen R., Claeys P., and Delannoy, J. J.: X. The Lebanese
speleothems and the Levant palaeoclimate, in:
Quaternary Environments, edited by: Bar, J. Y. and Enzel, Y., Climate Change, and Humans in the Levant, Cambridge
University Press, UK, accepted, 2015.
Waldmann, N., Stein, M., Ariztegui, D., and Starinsky, A.: Stratigraphy,
depositional environments and level reconstruction of the last interglacial
Lake Samra in the Dead Sea basin, Quaternary Res., 72, 1–15, 2009.
Wang, Y. J., Cheng, H., Edwards, R. L., An, Z. S., Wu, J. Y., Shen, C. C., and
Dorale, J. A.: A high-resolution absolute-dated Late Pleistocene monsoon
record from Hulu cave, China, Science, 294, 2345–2348, 2001.
Zanchetta, G., Drysdale R. N., Hellstrom J. C., Fallick, A. E., Isola, I.,
Gaganf, M. K., and Pareschi, M. T.: Enhanced rainfall in the Western
Mediterranean during deposition of sapropel S1: Stalagmite evidence from
Corchia cave (Central Italy), Quaternary Sci. Rev., 26, 279–286, 2007.
Ziegler, M., Tuenter, E., Lourens, L. J.: The precession phase of the boreal
summer monsoon as viewed from the eastern Mediterranean (ODP Site 968),
Quaternary Sci. Rev. 29, 1481–1490, 2010.