New stalagmites from Qadisha Cave (Lebanon) located at 1720 m above sea level provide a high-reso... more New stalagmites from Qadisha Cave (Lebanon) located at 1720 m above sea level provide a high-resolution and well-dated record for northern Mount Lebanon. The stalagmites grew discontinuously from 9.2 to 5.7 and at 3.5 ka, and they show a tendency to move from a more negative oxygen isotope signal at ~9.1 ka to a more positive signal at ~5.8 ka. Such a trend reflects a change from a wetter to a drier climate at high altitudes. The δ13C signal shows rapid shifts throughout the record and a decreasing trend toward more negative values in the mid-Holocene, suggesting enhanced soil activity. In the short-term trend, Qadisha stalagmites record rapid dry/wet changes on centennial scales, with a tendency to more rapid dry events toward the mid-Holocene. Such changes are characterized by overall good agreement between both geochemical proxies and stalagmite growth and might be affected by the seasonal variations in snow cover. The Qadisha record is in good agreement with other Levantine reco...
The HIGH-PASM project studies the climate variability on the Island of Cyprus for the last millen... more The HIGH-PASM project studies the climate variability on the Island of Cyprus for the last millennium. We combine highly resolved speleothem records with archived weather data for the last 140 years in order to corroborate and understand climate signals recorded in speleothems over the last millennium. An active stalagmite of 8 cm length was collected from Hot cave in 2021 along with other secondary carbonate deposits from Lapithos Qanat, and Amiandos and Argaka Dam tunnels. U-Th dating and lamina counting were combined to produce an age model for Hot cave and Lapithos Qanat. 800 stable isotope measurements were conducted on the Hot cave stalagmite, 250 on the Lapithos sample and 45 on each of the Amiandos and Argaka deposits. Meteorological data collected since 1885 from four stations were consolidated and compared to the yearly resolved Hot cave and Lapithos records.The Hot cave stalagmite grew continuously from 1330 to 2021 AD, the Lapithos sample covers the last 150 years and bo...
Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the p... more Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the paleoclimate in this special location of the Levant region. Lebanon is located in Central-Levant and presents a strong topographical & microclimate variability between the coast, the Mount-Lebanon range & the inner Bekaa plain. Paleoclimate studies published in the last years (Nader et al, 2007; Verheyden et al, 2008) on Jeita cave (l100 m asl) cover the Holocene period on a centennial scale (Cheng et al, 2015). The Jeita speleothem shows that northern Levant climate variability is dominated by a 500 year periodicity and that a persistent out-of-phase climate variability between the northern and southern Levant exists on a wide range of timescales when compared with other regional proxy records. To verify this interpretation, investigations were undertaken recently on speleothems from Qadisha cave located at 1720 m asl in northern Lebanon and conditioned by a high-mountain climate regime. Two stalagmites from Qadisha cave were retrieved in 2011 and 2014. Stalagmites Qad-1 covers the period from 6.482 ± 32 ka to 3.247 ± 127 ka BP 1950. The Qad-2 stalagmite is pre-dated and covers the period from 9.145 ± 21 to 5 ± 7 a BP 1950. Both Stalagmites were pre-screened using laser-ablation ICPMS to evaluate if periodic cycles (e.g. annual layers) are visible. Periodic variations of Mg/Ca, Sr/Ca, Ba/Ca and P/Ca suggest a climatic imprint that can be related to the layer thicknesses on the order of a few 10 µm to 100 µm. First U/Th dating together with the synchronicity of the elemental signals with the speleothem layering suggest an annual origin of the layering. This will be tested by further lamina counting combined with the U-Th dating. The elemental cycles can be used in the future to establish a yearly-resolved chronology with key ages provided by additional U/Th measurements and thus compared to the Jeita stalagmite record and other regional speleothem records (Palestine/Israel, Cyprus).
Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy... more Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy (France), with several hundred recorded sites (Rodet, 1992). Most occur in the Seine valley and along the Pays de Caux coastline. Few caves are several km long with active streamways; others are relict systems, sometimes preserved up to 90m asl. Many caves are infilled with sediment, sometimes totally and often display a paragenetic morphology. The sediments include reworked loessic material, clay, sand and flint derived from Palaeogene and Quaternary Clay-with-Flint and loess deposits that overlie the Chalk. The Normandy chalk limestone was always used as a natural resource for building construction, liming of agricultural fields and water exploitation. The Chalk exploitation created long manmade galleries in the Caumont quarry (50 km) which is presently subject to collapse processes. Relict caves near the plateau de Caux are generally connected to the surface through dissolution sinkholes leading to suffusion process and surface subsidence. The recent evolution of caves is closely related to natural hazards in the Normandy karst landscape. From a speleogenesis perspective, the spatial and vertical distribution of caves suggest a link between cave elevation , Chalk stratigraphy and the Seine river' incision. To better constrain the speleogenetic context, high resolution stratigraphy, detailed topographical analysis and age dating was used to understand the Quaternary evolution of the multi-level cave system along the Seine valley. Detailed stratigraphical logs derived from laser scans combined with palaeontological sampling suggest that cave development may be associated with particular inception horizons within the Chalk sequence (hardgrounds, sheet flints, marl seams), in particular the Light Point hard-ground/Shoreham marl level (Hoyez, 2008) at the top of the Lewes Nodular Chalk/base Seaford Chalk formations. The sediment infilling into caves attest to significant sediment inputs during various stages in the Quaternary. The studied caves along the Seine valley include: Caumont (15 m asl), Funiculaire (40 m asl), Mont Pivin (70 m asl) and Roche Percée (80 m asl) caves. Although previously partially dated (Rodet, 1992), they were recently reinves-tigated to help constrain the timing of sediment infilling into the caves and to derive a minimal model age for the cave development related to the incision of the Seine River. The River Seine has a very well-developed terrace system corresponding to seven incision stages covered by periglacial alluvial formations (Lautridou, 1983; Lecolle, 1989), but less well-dated. Along the Somme Basin adjacent to the Seine river, the highest terraces dated are up to 95 m asl. These terraces record valley incision that began at ∼1 Ma (Antoine et al., 2007), with several terraces dated by absolute ages and archeological findings. Recent palaeomagnetic data from the studied cave showed both normal and reversed polarity from the Funiculaire cave whereas higher-level caves showed normal polarity and may fall in the Jaramillo normal period (0.9-1.06 Ma). Having normal and reversed sediments in the Funiculaire cave appears to be in accordance with the nearest dated alluvial terrace (600 ±90 ka; ∼40m asl) in the Somme catchment (Antoine et al., 2007).
<p>Investigating palaeoclimate records is of major importance for evaluatin... more <p>Investigating palaeoclimate records is of major importance for evaluating the impact of past forcing factors on the evolution of ecosystems, megafauna and human dispersal, especially in Southern Patagonia where few records are available. We report on a 40 cm long flowstone core S6, and fragments of flowstone and a stalagmite from Cueva Chica. The samples were radiometrically dated (U-Th & <sup>14</sup>C) to construct age-depth models for the proxy profiles (δ<sup>13</sup>C, δ<sup>18</sup>O, and chemical composition). The speleothem proxy data are further informed by both petrographic analysis of the flowstone, and monitoring data. The main objectives of this work are to: i) reconstruct past climate variations using geochemical analyses conducted on the speleothems, and ii) assess the palaeoclimatic context of megafauna extinction in the area. The flowstone core S6 grew discontinuously from ~13 ka to ~1 ka with several possible hiatuses at ~10 ka BP, from 5.7 to 3.0 ka BP, and 2.5 to 1.8 ka BP (interpolated ages). Sample S8 grew from 6.8 to 5.8 ka BP and after 1.2 ka BP. Stable isotopes analyzed at sub-centennial resolution show a 3‰ range for δ<sup>18</sup>O, and more than 14‰ for δ<sup>13</sup>C, and the isotope ratios covary along the entire record. These changes are likely caused by kinetic fractionation and prior calcite precipitation (PCP), controlled mostly by changes in moisture availability. The sensitivity of the proxies to hydrological changes and PCP is further tested with indicators using μXRF element data. The multiproxy record from Cueva Chica suggests a wet phase from ~13 to 9 ka BP, likely related to strong westerlies in the Southern Hemisphere, preceded by a short dry/cold spell at ~13 ka BP. This early Holocene wet phase was followed by a colder/drier period from 8.5 to 5.8 ka BP, likely related to weaker westerlies, especially during the mid-Holocene. High precipitation and strong westerlies prevailed from 3.0 to 2.5 ka BP and in Medieval times. Our paleoclimate record implies that the presence of extensive megafauna, the development of Nothofagus forest and human arrival, all occurred during a climatically favorable wet/warm period ca. 13 to 9 ka BP, after the Antarctic Cold Reversal. However, the deterioration of the vegetation cover at the Cerro Benitez coinciding with high δ<sup>13</sup>C values excursions was initiated after ca. 11 ka BP. Previous studies suggest an extinction of major megafauna species (e.g., Mylodon, Smilodon, Panthera onca mesembrina) during this wet/warm period. Such climate-driven changes likely reduced the open ecosystem environment and may have led to local decline of herbivore populations. Later cooling/drying after ca. 9 ka may have contributed to the disappearance of megafauna and other large mamals (e.g., Hippidion Saldiasi).</p>
Lying at the transition between temperate Mediterranean domain and subtropical deserts, the Levan... more Lying at the transition between 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 dated last interglacial (MIS 5) stalagmite (129–84 ka) from the Kanaan Cave, Lebanon. Variations in growth rate, morphology and petrology have been measured to derive a palaeoclimatic record. The speleothem growth curve shows rapid growth rates during the peak of MIS 5e (126-124 ka), moderate growth rates between 103.5 and 99 ka and very low growth rates from 99 to 84 ka. On the basis of the good correlation between the speleothem morphology and growth rates with the isotopic response of continental records from northern and southern Levant, we relate high growth rate to wet conditions during the maximum MIS 5e and MIS 5c. The peak in growth rates corresponds to sapropel events in the eastern Mediterranean. Low growth rates during MIS 5d and 5b indicate a transition to drier condi...
Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two diffe... more Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two different morphological sections. The speleogenesis analysis of the cave forms based on geomorphological mapping of the galleries confirms that these sections were developed separately and were connected at an advanced level of the cave development. The geological characteristics of each section and the different hydrogeological network regimes in the galleries, as well as the tectonic frame, affect, at large scale, the karstic network system of Antelias area. The geomorphological approach led in this study helped us to understand the major contribution factors involved in the karstic system as well as their evolution from Late Quaternary times to our present time. The relative chronology based on cave mapping analysis can reveal main geological events and hydrological system development implicated in paleoenvironmental conditions. This approach is necessary to understand better datingrecords...
Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est pass... more Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est passionnant de tenter de comprendre tant ses paradoxes interpellent. De dimension restreinte (10 400 km²), il occupe un espace strategique particulier, au carrefour de la Mediterranee et de l'Orient arabe. Ce pays montagneux a connu l’occupation humaine depuis le paleolithique et a vu, tout au long de son histoire, sa domination constamment disputee par les plus grands empires, notamment la civilisati...
Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two diffe... more Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two different morphological sections. The speleogenesis analysis of the cave forms based on geomorphological mapping of the galleries confirms that these sections were developed separately and were connected at an advanced level of the cave development. The geological characteristics of each section and the different hydrogeological network regimes in the galleries, as well as the tectonic frame, affect, at large scale, the karstic network system of Antelias area. The geomorphological approach led in this study helped us to understand the major contribution factors involved in the karstic system as well as their evolution from Late Quaternary times to our present time. The relative chronology based on cave mapping analysis can reveal main geological events and hydrological system development implicated in paleoenvironmental conditions. This approach is necessary to understand better datingrecords...
Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est pass... more Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est passionnant de tenter de comprendre tant ses paradoxes interpellent. De dimension restreinte (10 400 km²), il occupe un espace strategique particulier, au carrefour de la Mediterranee et de l'Orient arabe. Ce pays montagneux a connu l’occupation humaine depuis le paleolithique et a vu, tout au long de son histoire, sa domination constamment disputee par les plus grands empires, notamment la civilisati...
Little is known about terrestrial climate dynamics in the Levant during the penultimate interglac... more Little is known about terrestrial climate dynamics in the Levant during the penultimate interglacial-glacial period. To decipher the palaeoclimatic history of the Marine Oxygen Isotope Stage (MIS) 6 glacial period, a well-dated stalagmite (~194 to ~154 ka) from Kanaan Cave on the Mediterranean coast in Lebanon was analyzed for its petrography, growth history, and stable isotope geochemistry. A resolved climate record has been recovered from this precisely U–Th dated speleothem, spanning the late MIS 7 and early MIS 6 at low resolution and the mid–MIS 6 at higher resolution. The stalagmite grew discontinuously from ~194 to ~163 ka. More consistent growth and higher growth rates between ~163 and ~154 ka are most probably linked to increased water recharge and thus more humid conditions. More distinct layering in the upper part of the speleothem suggests strong seasonality from ~163 ka to ~154 ka. Short-term oxygen and carbon isotope excursions were found between ~155 and ~163 ka. The ...
New stalagmites from Qadisha Cave (Lebanon) located at 1720 m above sea level provide a high-reso... more New stalagmites from Qadisha Cave (Lebanon) located at 1720 m above sea level provide a high-resolution and well-dated record for northern Mount Lebanon. The stalagmites grew discontinuously from 9.2 to 5.7 and at 3.5 ka, and they show a tendency to move from a more negative oxygen isotope signal at ~9.1 ka to a more positive signal at ~5.8 ka. Such a trend reflects a change from a wetter to a drier climate at high altitudes. The δ13C signal shows rapid shifts throughout the record and a decreasing trend toward more negative values in the mid-Holocene, suggesting enhanced soil activity. In the short-term trend, Qadisha stalagmites record rapid dry/wet changes on centennial scales, with a tendency to more rapid dry events toward the mid-Holocene. Such changes are characterized by overall good agreement between both geochemical proxies and stalagmite growth and might be affected by the seasonal variations in snow cover. The Qadisha record is in good agreement with other Levantine reco...
The HIGH-PASM project studies the climate variability on the Island of Cyprus for the last millen... more The HIGH-PASM project studies the climate variability on the Island of Cyprus for the last millennium. We combine highly resolved speleothem records with archived weather data for the last 140 years in order to corroborate and understand climate signals recorded in speleothems over the last millennium. An active stalagmite of 8 cm length was collected from Hot cave in 2021 along with other secondary carbonate deposits from Lapithos Qanat, and Amiandos and Argaka Dam tunnels. U-Th dating and lamina counting were combined to produce an age model for Hot cave and Lapithos Qanat. 800 stable isotope measurements were conducted on the Hot cave stalagmite, 250 on the Lapithos sample and 45 on each of the Amiandos and Argaka deposits. Meteorological data collected since 1885 from four stations were consolidated and compared to the yearly resolved Hot cave and Lapithos records.The Hot cave stalagmite grew continuously from 1330 to 2021 AD, the Lapithos sample covers the last 150 years and bo...
Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the p... more Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the paleoclimate in this special location of the Levant region. Lebanon is located in Central-Levant and presents a strong topographical & microclimate variability between the coast, the Mount-Lebanon range & the inner Bekaa plain. Paleoclimate studies published in the last years (Nader et al, 2007; Verheyden et al, 2008) on Jeita cave (l100 m asl) cover the Holocene period on a centennial scale (Cheng et al, 2015). The Jeita speleothem shows that northern Levant climate variability is dominated by a 500 year periodicity and that a persistent out-of-phase climate variability between the northern and southern Levant exists on a wide range of timescales when compared with other regional proxy records. To verify this interpretation, investigations were undertaken recently on speleothems from Qadisha cave located at 1720 m asl in northern Lebanon and conditioned by a high-mountain climate regime. Two stalagmites from Qadisha cave were retrieved in 2011 and 2014. Stalagmites Qad-1 covers the period from 6.482 ± 32 ka to 3.247 ± 127 ka BP 1950. The Qad-2 stalagmite is pre-dated and covers the period from 9.145 ± 21 to 5 ± 7 a BP 1950. Both Stalagmites were pre-screened using laser-ablation ICPMS to evaluate if periodic cycles (e.g. annual layers) are visible. Periodic variations of Mg/Ca, Sr/Ca, Ba/Ca and P/Ca suggest a climatic imprint that can be related to the layer thicknesses on the order of a few 10 µm to 100 µm. First U/Th dating together with the synchronicity of the elemental signals with the speleothem layering suggest an annual origin of the layering. This will be tested by further lamina counting combined with the U-Th dating. The elemental cycles can be used in the future to establish a yearly-resolved chronology with key ages provided by additional U/Th measurements and thus compared to the Jeita stalagmite record and other regional speleothem records (Palestine/Israel, Cyprus).
Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy... more Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy (France), with several hundred recorded sites (Rodet, 1992). Most occur in the Seine valley and along the Pays de Caux coastline. Few caves are several km long with active streamways; others are relict systems, sometimes preserved up to 90m asl. Many caves are infilled with sediment, sometimes totally and often display a paragenetic morphology. The sediments include reworked loessic material, clay, sand and flint derived from Palaeogene and Quaternary Clay-with-Flint and loess deposits that overlie the Chalk. The Normandy chalk limestone was always used as a natural resource for building construction, liming of agricultural fields and water exploitation. The Chalk exploitation created long manmade galleries in the Caumont quarry (50 km) which is presently subject to collapse processes. Relict caves near the plateau de Caux are generally connected to the surface through dissolution sinkholes leading to suffusion process and surface subsidence. The recent evolution of caves is closely related to natural hazards in the Normandy karst landscape. From a speleogenesis perspective, the spatial and vertical distribution of caves suggest a link between cave elevation , Chalk stratigraphy and the Seine river' incision. To better constrain the speleogenetic context, high resolution stratigraphy, detailed topographical analysis and age dating was used to understand the Quaternary evolution of the multi-level cave system along the Seine valley. Detailed stratigraphical logs derived from laser scans combined with palaeontological sampling suggest that cave development may be associated with particular inception horizons within the Chalk sequence (hardgrounds, sheet flints, marl seams), in particular the Light Point hard-ground/Shoreham marl level (Hoyez, 2008) at the top of the Lewes Nodular Chalk/base Seaford Chalk formations. The sediment infilling into caves attest to significant sediment inputs during various stages in the Quaternary. The studied caves along the Seine valley include: Caumont (15 m asl), Funiculaire (40 m asl), Mont Pivin (70 m asl) and Roche Percée (80 m asl) caves. Although previously partially dated (Rodet, 1992), they were recently reinves-tigated to help constrain the timing of sediment infilling into the caves and to derive a minimal model age for the cave development related to the incision of the Seine River. The River Seine has a very well-developed terrace system corresponding to seven incision stages covered by periglacial alluvial formations (Lautridou, 1983; Lecolle, 1989), but less well-dated. Along the Somme Basin adjacent to the Seine river, the highest terraces dated are up to 95 m asl. These terraces record valley incision that began at ∼1 Ma (Antoine et al., 2007), with several terraces dated by absolute ages and archeological findings. Recent palaeomagnetic data from the studied cave showed both normal and reversed polarity from the Funiculaire cave whereas higher-level caves showed normal polarity and may fall in the Jaramillo normal period (0.9-1.06 Ma). Having normal and reversed sediments in the Funiculaire cave appears to be in accordance with the nearest dated alluvial terrace (600 ±90 ka; ∼40m asl) in the Somme catchment (Antoine et al., 2007).
<p>Investigating palaeoclimate records is of major importance for evaluatin... more <p>Investigating palaeoclimate records is of major importance for evaluating the impact of past forcing factors on the evolution of ecosystems, megafauna and human dispersal, especially in Southern Patagonia where few records are available. We report on a 40 cm long flowstone core S6, and fragments of flowstone and a stalagmite from Cueva Chica. The samples were radiometrically dated (U-Th & <sup>14</sup>C) to construct age-depth models for the proxy profiles (δ<sup>13</sup>C, δ<sup>18</sup>O, and chemical composition). The speleothem proxy data are further informed by both petrographic analysis of the flowstone, and monitoring data. The main objectives of this work are to: i) reconstruct past climate variations using geochemical analyses conducted on the speleothems, and ii) assess the palaeoclimatic context of megafauna extinction in the area. The flowstone core S6 grew discontinuously from ~13 ka to ~1 ka with several possible hiatuses at ~10 ka BP, from 5.7 to 3.0 ka BP, and 2.5 to 1.8 ka BP (interpolated ages). Sample S8 grew from 6.8 to 5.8 ka BP and after 1.2 ka BP. Stable isotopes analyzed at sub-centennial resolution show a 3‰ range for δ<sup>18</sup>O, and more than 14‰ for δ<sup>13</sup>C, and the isotope ratios covary along the entire record. These changes are likely caused by kinetic fractionation and prior calcite precipitation (PCP), controlled mostly by changes in moisture availability. The sensitivity of the proxies to hydrological changes and PCP is further tested with indicators using μXRF element data. The multiproxy record from Cueva Chica suggests a wet phase from ~13 to 9 ka BP, likely related to strong westerlies in the Southern Hemisphere, preceded by a short dry/cold spell at ~13 ka BP. This early Holocene wet phase was followed by a colder/drier period from 8.5 to 5.8 ka BP, likely related to weaker westerlies, especially during the mid-Holocene. High precipitation and strong westerlies prevailed from 3.0 to 2.5 ka BP and in Medieval times. Our paleoclimate record implies that the presence of extensive megafauna, the development of Nothofagus forest and human arrival, all occurred during a climatically favorable wet/warm period ca. 13 to 9 ka BP, after the Antarctic Cold Reversal. However, the deterioration of the vegetation cover at the Cerro Benitez coinciding with high δ<sup>13</sup>C values excursions was initiated after ca. 11 ka BP. Previous studies suggest an extinction of major megafauna species (e.g., Mylodon, Smilodon, Panthera onca mesembrina) during this wet/warm period. Such climate-driven changes likely reduced the open ecosystem environment and may have led to local decline of herbivore populations. Later cooling/drying after ca. 9 ka may have contributed to the disappearance of megafauna and other large mamals (e.g., Hippidion Saldiasi).</p>
Lying at the transition between temperate Mediterranean domain and subtropical deserts, the Levan... more Lying at the transition between 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 dated last interglacial (MIS 5) stalagmite (129–84 ka) from the Kanaan Cave, Lebanon. Variations in growth rate, morphology and petrology have been measured to derive a palaeoclimatic record. The speleothem growth curve shows rapid growth rates during the peak of MIS 5e (126-124 ka), moderate growth rates between 103.5 and 99 ka and very low growth rates from 99 to 84 ka. On the basis of the good correlation between the speleothem morphology and growth rates with the isotopic response of continental records from northern and southern Levant, we relate high growth rate to wet conditions during the maximum MIS 5e and MIS 5c. The peak in growth rates corresponds to sapropel events in the eastern Mediterranean. Low growth rates during MIS 5d and 5b indicate a transition to drier condi...
Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two diffe... more Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two different morphological sections. The speleogenesis analysis of the cave forms based on geomorphological mapping of the galleries confirms that these sections were developed separately and were connected at an advanced level of the cave development. The geological characteristics of each section and the different hydrogeological network regimes in the galleries, as well as the tectonic frame, affect, at large scale, the karstic network system of Antelias area. The geomorphological approach led in this study helped us to understand the major contribution factors involved in the karstic system as well as their evolution from Late Quaternary times to our present time. The relative chronology based on cave mapping analysis can reveal main geological events and hydrological system development implicated in paleoenvironmental conditions. This approach is necessary to understand better datingrecords...
Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est pass... more Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est passionnant de tenter de comprendre tant ses paradoxes interpellent. De dimension restreinte (10 400 km²), il occupe un espace strategique particulier, au carrefour de la Mediterranee et de l'Orient arabe. Ce pays montagneux a connu l’occupation humaine depuis le paleolithique et a vu, tout au long de son histoire, sa domination constamment disputee par les plus grands empires, notamment la civilisati...
Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two diffe... more Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two different morphological sections. The speleogenesis analysis of the cave forms based on geomorphological mapping of the galleries confirms that these sections were developed separately and were connected at an advanced level of the cave development. The geological characteristics of each section and the different hydrogeological network regimes in the galleries, as well as the tectonic frame, affect, at large scale, the karstic network system of Antelias area. The geomorphological approach led in this study helped us to understand the major contribution factors involved in the karstic system as well as their evolution from Late Quaternary times to our present time. The relative chronology based on cave mapping analysis can reveal main geological events and hydrological system development implicated in paleoenvironmental conditions. This approach is necessary to understand better datingrecords...
Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est pass... more Le Liban est, sur une petite superficie, un espace d’une extraordinaire complexite qu’il est passionnant de tenter de comprendre tant ses paradoxes interpellent. De dimension restreinte (10 400 km²), il occupe un espace strategique particulier, au carrefour de la Mediterranee et de l'Orient arabe. Ce pays montagneux a connu l’occupation humaine depuis le paleolithique et a vu, tout au long de son histoire, sa domination constamment disputee par les plus grands empires, notamment la civilisati...
Little is known about terrestrial climate dynamics in the Levant during the penultimate interglac... more Little is known about terrestrial climate dynamics in the Levant during the penultimate interglacial-glacial period. To decipher the palaeoclimatic history of the Marine Oxygen Isotope Stage (MIS) 6 glacial period, a well-dated stalagmite (~194 to ~154 ka) from Kanaan Cave on the Mediterranean coast in Lebanon was analyzed for its petrography, growth history, and stable isotope geochemistry. A resolved climate record has been recovered from this precisely U–Th dated speleothem, spanning the late MIS 7 and early MIS 6 at low resolution and the mid–MIS 6 at higher resolution. The stalagmite grew discontinuously from ~194 to ~163 ka. More consistent growth and higher growth rates between ~163 and ~154 ka are most probably linked to increased water recharge and thus more humid conditions. More distinct layering in the upper part of the speleothem suggests strong seasonality from ~163 ka to ~154 ka. Short-term oxygen and carbon isotope excursions were found between ~155 and ~163 ka. The ...
Several studies on karst systems and geomorphology has been initiated in Lebanon recently by EDYT... more Several studies on karst systems and geomorphology has been initiated in Lebanon recently by EDYTEM laboratory UMR 5204-CNRS, France in collaboration with Saint Joseph University of Beirut and the Association Libanaise d'études spéléologiques (ALES). One of these researches aims at reconstituting: i) speleogenic evolution based on geomorphologic indicators, ii) karstogenesis reconstitution related with the downcutting of the Mediterranean hydrographic network (Antelias and Kelb river), iii) paleogeographical reconstitution of these tow valleys. Two caves have been chosen in each valley and a morphogenic analysis has been completed in each cave with a geomorphological approach. One of the main caves studied, downstream Antelias valley, is Kessarat cave with its underground river and its 4.6 km gallery development. A 6.45 m height section has been studied in the Junction gallery to reconstitute the deposition process of the sector in response to a collapse process. Stratigraphy ob...
Mount Lebanon consists mainly of carbonate rocks which contain numerous caves with an abundance o... more Mount Lebanon consists mainly of carbonate rocks which contain numerous caves with an abundance of well-preserved speleothem deposits. A 23 cm long stalagmite (K1-2010) was obtained from Kanaan cave, situated just north of Beirut within the western flank of central Mount Lebanon at 100 m altitude. To develop an age model for the speleothem, a suite of uranium series (U-Th) dates was performed in the NERC Isotope Geosciences Laboratory at the British Geological Survey. The speleothem displays two main segments: The lower segment (segment 1) is 8.2 cm long and displays a general growth axis varying from 8.5 cm diameter in the lower part to 6 cm in its middle part. This segment grew from at least 129.7 ± 0.8 ka to 111.8 ± 0.7 ka. Several hiatuses are observed and are probably linked to detrital layers. The higher segment (segment 2) is 12.3 cm long and displays a thinner diameter varying from 6.5 to 4 cm at its topmost part. This segment grew continuously from 102.5 ± 0.96 to 85.3 ± 0....
Several studies on karst systems and geomorphology has been initiated in Lebanon recently by EDYT... more Several studies on karst systems and geomorphology has been initiated in Lebanon recently by EDYTEM laboratory UMR 5204-CNRS, France in collaboration with Saint Joseph University of Beirut. One of these researches aims at reconstituting: i) speleogenic evolution based on geomorphologic indicators, ii) karstogenesis reconstitution related with the downcutting of the Mediterranean hydrographic network (Antelias and Kelb river), iii) palaeogeographical reconstitution of these tow valleys. Tow caves have been chosen in each valley and a morphogenic analysis has been completed in each cave with a geomorphologic approach. One of the main caves studied, downstream Antelias valley, is Kessarat cave with its underground river and its 4.6 km gallery development. After the morphogenic study of the cave, a 7.6 m. height section has been completed in the Jonction gallery on a sand slope deposit. Observations as well as grain size and morphoscopic analysis on sand layers have lead us to reconstit...
Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two diffe... more Mgharet Kanaan, a cave of 170 m. long and 100m. above Mediterranean sea level, presents two different morphological sections. The speleogenesis analysis of the cave forms based on geomorphological mapping of the galleries confirms that these sections were developed separately and were connected at an advanced level of the cave development. The geological characteristics of each section and the different hydrogeological network regimes in the galleries, as well as the tectonic frame, affect, at large scale, the karstic network system of Antelias area. The geomorphological approach led in this study helped us to understand the major contribution factors involved in the karstic system as well as their evolution from Late Quaternary times to our present time. The Relative chronology based on cave mapping analysis can reveal main geological events and hydrological system development implicated in paleoenvironmental conditions. This approach is necessary to understand better dating record...
Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the p... more Since 2005 studies on speleothems have been undertaken in Lebanon, aiming at reconstructing the paleoclimate in this special location of the Levant region. Lebanon is located in Central-Levant and presents a strong topographical & microclimate variability between the coast, the Mount-Lebanon range & the inner Bekaa plain. Paleoclimate studies published in the last years (Nader et al, 2007; Verheyden et al, 2008) on Jeita cave (l100 m asl) cover the Holocene period on a centennial scale (Cheng et al, 2015). The Jeita speleothem shows that northern Levant climate variability is dominated by a 500 year periodicity and that a persistent out-of-phase climate variability between the northern and southern Levant exists on a wide range of timescales when compared with other regional proxy records. To verify this interpretation, investigations were undertaken recently on speleothems from Qadisha cave located at 1720 m asl in northern Lebanon and conditioned by a high-mountain climate regime. Two stalagmites from Qadisha cave were retrieved in 2011 and 2014. Stalagmites Qad-1 covers the period from 6.482 ± 32 ka to 3.247 ± 127 ka BP 1950. The Qad-2 stalagmite is pre-dated and covers the period from 9.145 ± 21 to 5 ± 7 a BP 1950. Both Stalagmites were pre-screened using laser-ablation ICPMS to evaluate if periodic cycles (e.g. annual layers) are visible. Periodic variations of Mg/Ca, Sr/Ca, Ba/Ca and P/Ca suggest a climatic imprint that can be related to the layer thicknesses on the order of a few 10 µm to 100 µm. First U/Th dating together with the synchronicity of the elemental signals with the speleothem layering suggest an annual origin of the layering. This will be tested by further lamina counting combined with the U-Th dating. The elemental cycles can be used in the future to establish a yearly-resolved chronology with key ages provided by additional U/Th measurements and thus compared to the Jeita stalagmite record and other regional speleothem records (Palestine/Israel, Cyprus).
Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy... more Caves in the Upper Cretaceous Chalk limestone are generally rare, but more common in the Normandy (France), with several hundred recorded sites (Rodet, 1992). Most occur in the Seine valley and along the Pays de Caux coastline. Few caves are several km long with active streamways; others are relict systems, sometimes preserved up to 90m asl. Many caves are infilled with sediment, sometimes totally and often display a paragenetic morphology. The sediments include reworked loessic material, clay, sand and flint derived from Palaeogene and Quaternary Clay-with-Flint and loess deposits that overlie the Chalk. The Normandy chalk limestone was always used as a natural resource for building construction, liming of agricultural fields and water exploitation. The Chalk exploitation created long manmade galleries in the Caumont quarry (50 km) which is presently subject to collapse processes. Relict caves near the plateau de Caux are generally connected to the surface through dissolution sinkholes leading to suffusion process and surface subsidence. The recent evolution of caves is closely related to natural hazards in the Normandy karst landscape. From a speleogenesis perspective, the spatial and vertical distribution of caves suggest a link between cave elevation , Chalk stratigraphy and the Seine river' incision. To better constrain the speleogenetic context, high resolution stratigraphy, detailed topographical analysis and age dating was used to understand the Quaternary evolution of the multi-level cave system along the Seine valley. Detailed stratigraphical logs derived from laser scans combined with palaeontological sampling suggest that cave development may be associated with particular inception horizons within the Chalk sequence (hardgrounds, sheet flints, marl seams), in particular the Light Point hard-ground/Shoreham marl level (Hoyez, 2008) at the top of the Lewes Nodular Chalk/base Seaford Chalk formations. The sediment infilling into caves attest to significant sediment inputs during various stages in the Quaternary. The studied caves along the Seine valley include: Caumont (15 m asl), Funiculaire (40 m asl), Mont Pivin (70 m asl) and Roche Percée (80 m asl) caves. Although previously partially dated (Rodet, 1992), they were recently reinves-tigated to help constrain the timing of sediment infilling into the caves and to derive a minimal model age for the cave development related to the incision of the Seine River. The River Seine has a very well-developed terrace system corresponding to seven incision stages covered by periglacial alluvial formations (Lautridou, 1983; Lecolle, 1989), but less well-dated. Along the Somme Basin adjacent to the Seine river, the highest terraces dated are up to 95 m asl. These terraces record valley incision that began at ∼1 Ma (Antoine et al., 2007), with several terraces dated by absolute ages and archeological findings. Recent palaeomagnetic data from the studied cave showed both normal and reversed polarity from the Funiculaire cave whereas higher-level caves showed normal polarity and may fall in the Jaramillo normal period (0.9-1.06 Ma). Having normal and reversed sediments in the Funiculaire cave appears to be in accordance with the nearest dated alluvial terrace (600 ±90 ka; ∼40m asl) in the Somme catchment (Antoine et al., 2007).
Présentation : La croissance des stalagmites dans les grottes est intimement liée aux conditions ... more Présentation : La croissance des stalagmites dans les grottes est intimement liée aux conditions climatiques extérieures. Pour cela, l'étude à haute résolution des signaux chimiques contenus dans leur structure interne (lamines) permet de reconstituer les variations des paramètres climatiques et donc de la saisonnalité du climat actuel et passé. Cependant, les études récentes a ont démontré un signal saisonnier dans les paramètres chimiques des stalagmites (Isotopes stables et éléments traces), fait assez particulier dans les cavités belges. Les mesures ponctuelles de températures et de PCO2 dans la salle du Dôme indiquent ainsi une influence de la climatologie souterraine sur ces paramètres et un certain déphasage avec les variations saisonnières en surface. La topographie de la grotte influence aussi localement cette climatologie souterraine. Une meilleure compréhension du fonctionnement actuel de la cavité avec un suivi plus étendu spatialement est nécessaire afin de mieux interpréter le signal saisonnier par l'identification: i) des valeurs seuils de température et de CO2 à l'origine du déphasage entre les changements saisonniers souterrains et ceux de surface, ii) des effets de site (tube à vent, piège à froid) sur les paramètres climatiques souterrains.
Little is known about terrestrial climate dynamics of the Levant during the MIS-6 and MIS-7 perio... more Little is known about terrestrial climate dynamics of the Levant during the MIS-6 and MIS-7 periods. A stalagmite (~194 to ~154 ka) from Kanaan cave, located from Lebanon (East Med. basin), is examined for its petrography, growth history and stable isotope geochemistry to answer the climate instability pattern of the glacial MIS 6 and possible wet phases. A highly resolved continental climate record has been recovered from this U–Th-dated speleothem, spanning the late-MIS 7a at low resolution and the mid-MIS 6 period at higher resolution. The stalagmite grew discontinuously from ~194 to 163 ka. More regular growth and higher growth rates from ~163 to ~154 ka are most probably linked to increased water recharge in the vadose zone and thus more humid conditions. More distinct layering in the upper section compared to the basal part of the stalagmite suggests strong seasonality from ~163 ka to ~154 ka. Short-term oxygen & carbon isotope excursions were found between ~155 and ~163 ka. The inferred Kanaan cave humid intervals during the mid-MIS 6 period follow variations of pollen records in the Eastern and Western Med. basins & correlate well with the synthetic Greenland records and East Asian Summer Monsoon Interstadials, indicating short warm/wet periods
La grotte de Han-sur-Lesse dispose d'une richesse patrimoniale scientifique illustrée par diverse... more La grotte de Han-sur-Lesse dispose d'une richesse patrimoniale scientifique illustrée par diverses recherches archéologiques, géomorphologiques, hydrologiques et paléoclimatiques depuis 1829. Or ces différentes études sollicitent un outil plus efficace permettant de les replacer dans un cadre global et spatial. Afin d'avoir une base de travail efficace, une synthèse de l'état de l'art de ces études sera produite sous forme de base de données spatialisées. Une base de données des r e c h e r c h e s e f f e c t u é e s d a n s l a g r o t t e e s t e n c o u r s d e c o n s t r u c t i o n d e p u i s 2 0 1 4 .
Lebanon landscape is characterized by tow karstic mountain chains with a variety of surface karst... more Lebanon landscape is characterized by tow karstic mountain chains with a variety of surface karstic forms as well as endokarstic network systems. A research project on Lebanon's karst geomorphology was conducted recently by EDYTEM laboratory CNRS-UMR 5204, France and Saint-Joseph University of Beirut and aims at reconstituting: i) speleogenic evolution based on geomorphologic indicators, ii) karstogenesis evolution related with the downcutting of the Mediterranean hydrographic network (Antelias river), iii) palaeogeographical stages of these valleys. Antelias valley is chosen as one of the main karst study sites. Located 10 km north of Beirut city, Antelias river has 20.4 km 2 of catchment area and drains directly to the Mediterranean sea. Tow caves were selected downstream of the valley: Kanaan cave (fossil cavern at 100 meters a.s.l.) and Kessarat active network with 4.6 km of multiphase canyon galleries, located between 57 and 96 meters altitude. A morphogenic analysis has been completed in each cave with a geomorphologic approach, using detailed cartography, cross sections surveys as well as deposits analysis. The study completed in both Kanaan and Kessarat caves determined a paleo-phreatic zone at 95-98 meters a.s.l. This first erosional level is attributed to paragenetic forms such as tubular galleries, semi tubular channel and anastomosis ceiling, clay deposits notches and dissolution pockets. The water level migration downstream of the valley has disconnected Kanaan cave from the drainage network while Kassarat underground river entrenched a meander passage below the initial phreatic level. The base of Kassarat Vadose canyon at 65 meters is characterized by a semi-phreatic tube, while down cutted clay deposits are located at 70-75 meters, revealing a probable second erosional level with a long term stabilization of the water table level around these altitudes. The major siphon of Kessarat river is located actually at 57 meters and connected to Fouar resurgence spring. Antelias river is fed by Fouar spring, located at 33 meters a.s.l. between the Jurassic limestone and the cretaceous impermeable Aptien/Albien stratas. This contact constitutes the water table level of the karst drainage as well as the Antelias river hydrographic network. The actual stage of the cave genesis and the valley'drainage system is attributed to a transitory erosional phase. The karstic levels revealed by the speleogenic study, the first around 100 meters and the second at 65-70 meters are controlled by a local base level. Scallops direction in Kanaan cave showed a dominant NNO paleo-flow direction closest to the river location rather than the Mediterranean sea. We conclude that Antelias river thalweg was the base level of Kanaan and Kassarat cave at the time when the karstic active level of the valley was at 100 meters and Antelias valley was less downcutted. Local base levels such as Antelias thalweg and Fouar spring existed and affected the valley drainage system even with a close Mediterranean sea level (1.8 km from the valley to the shoreline). However, slight differences between water table level (Fouar spring and river thalweg) and sea base level (Mediterranean Sea) are to be taken into consideration. The Aptien-Albien hydrogeological barrier could
Jeita grotto is one of the longest cave in the Near-East region with more than 10 000 meters of u... more Jeita grotto is one of the longest cave in the Near-East region with more than 10 000 meters of underground network gallery. Situated 18 km north of Beirut, it holds the record of the longest stalactite in the world with 8.2 meters long. In 2011, Jeita cave was one of the 28 st finalists for the selection of the new seven natural wonders of the world competition. It was the only cave site represented in this final list. Adding to these points, the touristic value of this site that makes Jeita cave the first visited site in Lebanon: explored totally by lebanese cavers in 1950's, it was opened to the public in 1958 and later on in 1969, after the discovery of the upper galleries. Jeita cave receives, in average, more than 280 000 visitors per year (Source: les sommets du tourisme, Chamonix, 2009). With all these natural and historical characteristics, most visitors do not know the scientific value of this site. Lack of visual and material information in the touristic path encourage the visitors to ask speleologists about the cave, when they are on site. One of these questions was about the genesis of the grotto: how this big underground canyon of 75 meters deep was formed? These requests for information encourage us to put up new challenges throughout our study on the cave geomorphology and speleogenesis. Therefore, a research project on Lebanon's karst geomorphology was carry out since 2009, by Saint Joseph University of Beirut in collaboration with EDYTEM laboratory UMR 5204-CNRS, France. These studies aims at reconstruct: i) speleogenic evolution of caves based on geomorphologic indicators, ii) karstogenesis reconstitution related with the downcutting of the Mediterranean hydrographic network (Antelias and Kelb river), iii) palaeogeographical reconstitution of these tow valleys. On of these cave was Jeita grotto located on the north side of Kelb River. We wanted to expose these results to the public concerning Jeita site, once the cave history uncovered. Our work consists at reconstituting the downcutting stages of Jeita underground canyon according to the karst base level, which is the kelb river. The methods used to our study were based on: i) completing a high-resolution geomorphology map of the cave combined with detailed cross-sections of the canyon and retrace paleohydrological records from sediments sequence. On one hand, six specific sites were selected in the upper and lower galleries and surveyed. The detailed map led us to complete an inventory of erosion processes (dissolution, fluvial, collapse) that participated in the cave formation. Adding to this method, 26 detailed cross-sections were completed and showed us the cave original morphology assigned to fluvial erosion of the underground river. While geomorphology map helped us to understand the spatial distribution of deposits, cross-sections were measured to illustrate the erosion processes succession in the canyon. Common shapes and aspects on different sites were revealed. The combination of these two methods has led us to reconstruct four stages of Jeita canyon history based on a relative chronology approach. Further datations will be made and published in order to insert Jeita genesis in Lebanon natural history. On the other hand, tow in-fillings sequences in both upper and lower galleries were completed. A grain-size analysis has revealed the deposit dynamics and the palaeoflows of the underground river such as velocity variations and flows directions. The paleohydrological records contributed at the revealing Jeita Underground River dynamics. As these scientific results helped us to uncover the cave history, our suggestion is to respond on tourist's scientific curiosity by implementing educational boards in different locations, outside and inside Jeita cave. These backboards
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