- Email: [email protected]
Human subsistence changes during the late Holocene: resource overexploitation or climate change in the upper Atuel river valley, Argentina
Abstracts / Quaternary International 279-280 (2012) 346–461
THE IMPORTANCE OF A WELL DEFINED GSSP FOR THE UPPER PLEISTOCENE FOR THE RECONSTRUCTION OF CLIMATE AND SEA LEVEL Alessandra Negri. Universita’ Politecnica delle Marche, Italy E-mail address: [email protected]
The importance of a well established Chronostratigraphy is a starting point for the correlation of the various archives used for the reconstruction of climate, regional sea level fluctuations and tectonic movements. In this frame the Italian Commission on Stratigraphy of the SGI is seeking for a marine section suitable for defining the Upper Pleistocene GSSP. This Series has been usually identified with the Tyrrhenian Stage which in the wake of formalization received different meaning from stratigraphers and geomorphologits. Hence, the proposal of a new Upper Pleistocene Stage name and type area, the Tarentian, made in 1994. Criteria for defining the Tarentian Stage and selecting its GSSP can be the beginning of MIS 5 (? 134 ka) and the beginning of MIS 1 (? 10 ka) taken for the base of the Holocene. The Tarentian Stage contains also MIS 5.5 highstand with its peak at 125 ka. Upper Pleistocene marine deposits of thickness exceeding 1 to 2 m are rarely exposed on land except for some Mediterranean countries. Italian coastal areas keep some hundreds of marine Upper Pleistocene sites. They are all characterized by the so called Strombus bubonius Senegalese tropical fauna (Persististrombus latus (Gmelin, 1791) (¼ bubonius (Lamarck, 1822). They are found at different elevations from 130 to +170 m depending on the strong differential crustal mobility of the area. The best up to some 10 m thick Upper Pleistocene marine sections are exposed at the coast of the Gulf of Taranto facing the Ionian Sea. Here, where a well exposed marine succession has been uplifted very recently, we have explored the possibility to find a suitable GSSP for the upper Pleistocene adopting a combined stratigraphic approach based on litho bio and magnetotsratigraphy and corroborated by paleoecological and, U-Th analyses.
349
Grass-dominated ecosystems cover one-third of Earth's land surface, influence key biogeochemical processes, and serve as major food sources. A challenge in studying the response of grasslands to environmental change in paleorecords is that grass pollen generally cannot be morphologically identified below the family level, which means that pollen assemblages are uninformative about C3 and C4 grass variations. To overcome this difficulty, we have developed a novel technique for analyzing the stable carbon isotopic composition of individual grass-pollen grains using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer. Here we report this new approach, including its use in addressing factors controlling (1) the origin of C4 photosynthesis in the grass family and (2) variations in C4-grass abundance during the late Quaternary in East Africa. Our results from herbarium specimens and lakesediment surface samples indicate that SPIRAL reliably distinguishes C3 and C4 grasses and reflects their proportions on the landscape. A major paradigm concerning grassland evolution is that low pCO2 was an important driver for the origin of C4 grasses, but analysis of samples from Europe indicates that C4 grasses existed before pCO2 declined during the Oligocene. Preliminary SPIRAL data from Lake Challa in equatorial East Africa indicate that C4-grass abundance in the Mt. Kilimanjaro area averaged 45 25% during the last 25,000 yr BP, with generally higher values when moisture availability was low. Low pCO2 during the last glaciation did not lead to uniformly high values of C4-grass abundance, which contrasts with bulk-sediment and leaf-wax d13C records, probably because of differences in the nature and source area of these indicators. Strikingly, C4-grass pollen abundance has reached its highest levels of the past 25,000 years only within the last millennium. HUMAN SUBSISTENCE CHANGES DURING THE LATE HOLOCENE: RESOURCE OVEREXPLOITATION OR CLIMATE CHANGE IN THE UPPER ATUEL RIVER VALLEY, ARGENTINA Gustavo Neme. Conciet-Museo de Historia natural de San Rafael, Argentina E-mail address: [email protected]
RECONSTITUTION OF THE GROUNDWATER PALAEOFLOW OF KESSARAT CAVE, ANTELIAS VALLEY, LEBANON: A GEOMORPHOLOGICAL APPROACH IN PALAEOHYDROLOGICAL RECORDS ANALYSIS
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 reconstitute the deposit dynamics and the palaeoflows of the underground river such as velocity variations and flows directions. These results helped us to identify some aspects of the geomorphological environments of the Kessarat underground river. These results have been demonstrated within the karstic context and the morphogenesis scenarios of Kessarat cave.
Significant changes in human subsistence strategies took place during the Holocene in the high-altitude environments of central west Argentina. During the last 9000 yr BP, the mountain environments in Atuel River had been exploited but it was during the last 2000 yr BP that they had been effectively and completely occupied. Important changes in the land use had been also recorded including the consumption of smaller preys, greater plant-use diversity and the appearance of new technologies (bow and arrow, pottery). The main explanation for these changes has been until now the resources overexploitation by humans. At the same time scattered paleoenvironmental information suggested that some environmental changes took place, but still the real impact over the human population is not completely understood. In this paper we present the archaeological record from El Sosneado Locality in the Atuel River upper basin (34 470 S, 69 520 W; 2000 m asl; Arroyo Malo -3, Arroyo Malo 1 and Laguna El Sosneado-3), and its comparison with high resolution paleoenvironmental information from a core from El Sosneado lake (ES). The archaeological information includes archaeofaunal, archaeobotanical, and charcoal records. Pollen and charcoal records analyzed from ES core were used as proxy data to reconstruct vegetation, fire and environmental changes over the last 7.000 cal yr BP. This record shows the development of Andean-Patagonian shrub steppes with wetter and colder than present conditions and frequent fire events between 6400 and 1900 cal yr BP. After that an abrupt change towards more sparse Patagonia-Monte vegetation indicates drier and warmer conditions. Intent to integrate this different line of research is presented in order to improve our comprehension of human-environment relationship in mountain ecosystems.
USING SPIRAL (SINGLE POLLEN ISOTOPE RATIO ANALYSIS) TO ELUCIDATE GRASSLAND RESPONSES TO ENVIRONMENTAL CHANGE DURING THE LATE QUATERNARY AND BEYOND
ASSESSING THE TIME OF FINAL DEPOSITION OF A YOUNGEST TOBA TUFF DEPOSIT IN THE MIDDLE SON VALLEY, INDIA – A LUMINESCENCE APPROACH USING MULTIPLE METHODS
David Nelson. University of Maryland Center for Environmental Sc, United States
Christina M. Neudorf. Centre for Archaeological Science, School of Earth, Australia
E-mail address: [email protected]
E-mail address: [email protected]
Carole Nehme. Saint Jospeh University, Human science faculty, Ge, Lebanon E-mail address: [email protected]
THE IMPORTANCE OF A WELL DEFINED GSSP FOR THE UPPER PLEISTOCENE FOR THE RECONSTRUCTION OF CLIMATE AND SEA LEVEL Alessandra Negri. Universita’ Politecnica delle Marche, Italy E-mail address: [email protected]
The importance of a well established Chronostratigraphy is a starting point for the correlation of the various archives used for the reconstruction of climate, regional sea level fluctuations and tectonic movements. In this frame the Italian Commission on Stratigraphy of the SGI is seeking for a marine section suitable for defining the Upper Pleistocene GSSP. This Series has been usually identified with the Tyrrhenian Stage which in the wake of formalization received different meaning from stratigraphers and geomorphologits. Hence, the proposal of a new Upper Pleistocene Stage name and type area, the Tarentian, made in 1994. Criteria for defining the Tarentian Stage and selecting its GSSP can be the beginning of MIS 5 (? 134 ka) and the beginning of MIS 1 (? 10 ka) taken for the base of the Holocene. The Tarentian Stage contains also MIS 5.5 highstand with its peak at 125 ka. Upper Pleistocene marine deposits of thickness exceeding 1 to 2 m are rarely exposed on land except for some Mediterranean countries. Italian coastal areas keep some hundreds of marine Upper Pleistocene sites. They are all characterized by the so called Strombus bubonius Senegalese tropical fauna (Persististrombus latus (Gmelin, 1791) (¼ bubonius (Lamarck, 1822). They are found at different elevations from 130 to +170 m depending on the strong differential crustal mobility of the area. The best up to some 10 m thick Upper Pleistocene marine sections are exposed at the coast of the Gulf of Taranto facing the Ionian Sea. Here, where a well exposed marine succession has been uplifted very recently, we have explored the possibility to find a suitable GSSP for the upper Pleistocene adopting a combined stratigraphic approach based on litho bio and magnetotsratigraphy and corroborated by paleoecological and, U-Th analyses.
349
Grass-dominated ecosystems cover one-third of Earth's land surface, influence key biogeochemical processes, and serve as major food sources. A challenge in studying the response of grasslands to environmental change in paleorecords is that grass pollen generally cannot be morphologically identified below the family level, which means that pollen assemblages are uninformative about C3 and C4 grass variations. To overcome this difficulty, we have developed a novel technique for analyzing the stable carbon isotopic composition of individual grass-pollen grains using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer. Here we report this new approach, including its use in addressing factors controlling (1) the origin of C4 photosynthesis in the grass family and (2) variations in C4-grass abundance during the late Quaternary in East Africa. Our results from herbarium specimens and lakesediment surface samples indicate that SPIRAL reliably distinguishes C3 and C4 grasses and reflects their proportions on the landscape. A major paradigm concerning grassland evolution is that low pCO2 was an important driver for the origin of C4 grasses, but analysis of samples from Europe indicates that C4 grasses existed before pCO2 declined during the Oligocene. Preliminary SPIRAL data from Lake Challa in equatorial East Africa indicate that C4-grass abundance in the Mt. Kilimanjaro area averaged 45 25% during the last 25,000 yr BP, with generally higher values when moisture availability was low. Low pCO2 during the last glaciation did not lead to uniformly high values of C4-grass abundance, which contrasts with bulk-sediment and leaf-wax d13C records, probably because of differences in the nature and source area of these indicators. Strikingly, C4-grass pollen abundance has reached its highest levels of the past 25,000 years only within the last millennium. HUMAN SUBSISTENCE CHANGES DURING THE LATE HOLOCENE: RESOURCE OVEREXPLOITATION OR CLIMATE CHANGE IN THE UPPER ATUEL RIVER VALLEY, ARGENTINA Gustavo Neme. Conciet-Museo de Historia natural de San Rafael, Argentina E-mail address: [email protected]
RECONSTITUTION OF THE GROUNDWATER PALAEOFLOW OF KESSARAT CAVE, ANTELIAS VALLEY, LEBANON: A GEOMORPHOLOGICAL APPROACH IN PALAEOHYDROLOGICAL RECORDS ANALYSIS
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 reconstitute the deposit dynamics and the palaeoflows of the underground river such as velocity variations and flows directions. These results helped us to identify some aspects of the geomorphological environments of the Kessarat underground river. These results have been demonstrated within the karstic context and the morphogenesis scenarios of Kessarat cave.
Significant changes in human subsistence strategies took place during the Holocene in the high-altitude environments of central west Argentina. During the last 9000 yr BP, the mountain environments in Atuel River had been exploited but it was during the last 2000 yr BP that they had been effectively and completely occupied. Important changes in the land use had been also recorded including the consumption of smaller preys, greater plant-use diversity and the appearance of new technologies (bow and arrow, pottery). The main explanation for these changes has been until now the resources overexploitation by humans. At the same time scattered paleoenvironmental information suggested that some environmental changes took place, but still the real impact over the human population is not completely understood. In this paper we present the archaeological record from El Sosneado Locality in the Atuel River upper basin (34 470 S, 69 520 W; 2000 m asl; Arroyo Malo -3, Arroyo Malo 1 and Laguna El Sosneado-3), and its comparison with high resolution paleoenvironmental information from a core from El Sosneado lake (ES). The archaeological information includes archaeofaunal, archaeobotanical, and charcoal records. Pollen and charcoal records analyzed from ES core were used as proxy data to reconstruct vegetation, fire and environmental changes over the last 7.000 cal yr BP. This record shows the development of Andean-Patagonian shrub steppes with wetter and colder than present conditions and frequent fire events between 6400 and 1900 cal yr BP. After that an abrupt change towards more sparse Patagonia-Monte vegetation indicates drier and warmer conditions. Intent to integrate this different line of research is presented in order to improve our comprehension of human-environment relationship in mountain ecosystems.
USING SPIRAL (SINGLE POLLEN ISOTOPE RATIO ANALYSIS) TO ELUCIDATE GRASSLAND RESPONSES TO ENVIRONMENTAL CHANGE DURING THE LATE QUATERNARY AND BEYOND
ASSESSING THE TIME OF FINAL DEPOSITION OF A YOUNGEST TOBA TUFF DEPOSIT IN THE MIDDLE SON VALLEY, INDIA – A LUMINESCENCE APPROACH USING MULTIPLE METHODS
David Nelson. University of Maryland Center for Environmental Sc, United States
Christina M. Neudorf. Centre for Archaeological Science, School of Earth, Australia
E-mail address: [email protected]
E-mail address: [email protected]
Carole Nehme. Saint Jospeh University, Human science faculty, Ge, Lebanon E-mail address: [email protected]