- Email: [email protected]
The Magdalenian in NE Iberia
154
Abstracts / Quaternary International 279-280 (2012) 121–232
generated by the 1498 Meio earthquake (M8.2-8.4) that occurred along the Nankai Through, on the coastal-fluvial evolution of the area. This research is of geoarchaeological value as historical sources document the sudden decline at the end of the 15th century of an important harbour town, Hashimoto, located along the Hamana river. This river connected the Pacific Ocean with a coastal embayment closed by a sand barrier (i.e. the present-day called Hamana lake) before the 15th century. The reconstruction of the palaeocourse of the Hamana river was carried out on the basis of detailed facies analyses of undisturbed sediment cores (geoslicer and drilling). This palaeochannel was detected along the western side of the present-day Hamana coastal embayment. It seems that due to the Meio Tsunami, its mouth became abruptly closed due to the migration of huge volumes of sand initiating the development of a marsh environment upstream along the channel. Moreover, it is known that due to the 1498 Meio tsunami, the Hamana back-barrier sheltered environment became again connected to the Pacific Ocean due to breaching of the sand barrier. Both environmental changes are synchronous with the sudden decline of the harbour town Hashimoto. These data suggest that the breaking off of the water route connecting the harbour town Hashimoto and Pacific Ocean potentially led to the decline of the harbour. CHANGES IN 230TH-NORMALIZED FLUX OF BIOGENIC COMPONENTS RECORDED IN THE SOUTH CHILEAN MARGIN OVER THE PAST 13,000 YEARS Miho Fukuda. University of Tsukuba, Japan E-mail address: [email protected]
During the last glacial maximum, the atmospheric partial pressure of CO2 (pCO2atm) was quite low, 180 ppm and rapidly increased to 280 ppm during the last deglacation (Monnin et al., 2001). Although the biological pump is one of the sinks of pCO2atm, how much biological pump had contributed to the atmospheric pCO2 reduction throughout the deglaciation? Its evaluation is still insufficient. The aims of this study is to understand the temporal changes of Thorium-230 (230Th)-normalized export fluxes of biogenic materials, namely biogenic components, total organic carbon (TOC), total nitrogen (TN) and biogenic opal (Opal), which are commonly utilized as proxies for productivity, recorded in a sediment core (PC3) collected near the mouth of Strait of Magellan, Pacific side (52 S). When 230 Th was born to decay of dissolved Uranium-234 (234U) in the seawater, it is promptly scavenged by adsorption on settling particles with a short residence time (w 40 years). The 230Th-normalization method is based on the assumption that the flux of scavenged 230Th reaching the seafloor is known and equal to the rate of 230Th production from the decay of 234U in the overlying water column. Furthermore, 230Th input associated with terrigenous materials can be corrected by 232Th activity. The 230Thnormalized fluxes of TOC, TN and biogenic Opal during the Younger Dryas (YD) were 30%, 40% and 60% higher than those during the Holocene, respectively. Biogenic opal flux is a proxy of relative strength of upwelling. High values of TOC, TN, and Opal during the YD suggest relatively high marine productivity and biological pump due to enhanced upwelling rather than that during the Holocene. THE MAGDALENIAN IN NE IBERIA
Parco and Montlleó sites have enabled the reconstruction of the Tardiglacial palaeoenvironment for the southeastern Pyrenees area. However, other sites from the southern part of the country are also providing very interesting information about climate, as well as faunal and floral elements. Some malacological remains found in Montlleó come from the Mediterranean coast, but others come from the Cantabrian area, thus opening a new route of connection between both seas during the Magdalenian. We have also a few artistic evidences comes from Taverna cave, Parellada IV, Fornols Haut and Molí del Salt sites. One of the most significant findings of our research is the archaeological confirmation of the existence of a mountain pass across the Pyrenees during the Magdalenian. Some raw materials found in Montlleó are from French origin, others come from the southern slopes of the Pyrenees, and other ones could come from either side. The site is near the most western path opened during the last glaciation for crossing the Pyrenees. Thus, people and materials may well have circulated across the Pyrenees through this corridor. TEMPORAL CHANGE OF THE LATE PLEISTOCENE–HOLOCENE BARRIERLAGOON COMPLEX OF THE ECHIGO PLAIN, CENTRAL JAPAN Ayako Funabiki. Geological Survey of Japan, Japan E-mail address: [email protected]
The depositional history of the barrier-lagoon systems of the Echigo Plain, central Japan, was investigated using more than 10,000 borehole logs and 27 radiocarbon dated cores. The combined effect of sea-level rise during the last deglacial, sediment discharge from the Shinano and Agano Rivers, and subsidence in the Echigo Plain Western Margin Fault Zone resulted in deposition of a 160-m-thick incised valley fill sequence, barrier-lagoon systems, and two marine flooding surfaces. The coastline of the plain is about 80 km long and there are three barrier systems. The oldest marine flooding surface was dated at around 9 cal kyr BP, when sea level rose rapidly, marked by a change from a tidal marsh environment to an inner bay or offshore environment. This environmental change manifested as a ravinement surface in some borehole data and was recognized up to 10 km landward. The first barrier-lagoon system formed during 9–8 cal kyr BP. In the southern Echigo plain, this system was succeeded by the second and third barrier-lagoon systems, which developed in response to subsidence in the Echigo Plain Western Margin Fault Zone. However, in areas distant from the fault system, only one barrier-lagoon system was developed. The second marine flooding surface formed during 8–7 cal kyr BP and caused the most extensive incursion of brackish water into the lagoonal area. This age corresponds to that of the maximum flooding surface of the Echigo Plain identified in previous studies (e.g., Omura et al., 2006). The second marine flooding was followed by seaward progradation of the second, and then the third, barrier-lagoon systems. The Echigo Plain is still subsiding at about 3 mm/yr, as indicated by the dip of the marine flooding surfaces towards the thalweg of paleo-River. HOLOCENE EVOLUTION OF NATURAL LEVEES OF THE SONG HONG (RED RIVER) DELTA, NORTHERN VIETNAM Ayako Funabiki. Geological Survey of Japan, Japan E-mail address: [email protected]
José María Fullola. SERP Universitat de Barcelona, Spain E-mail address: [email protected]
The Magdalenian is the first Upper Palaeolithic period to show a widespread human occupation along the northeastern territories of Iberia. Several sites have been located across the plains and mountains extending from the Pyrenean valleys of the Segre River to the mouth of the Ebro River. The oldest dates (17th millennium BP) were obtained at the open-air site of Montlleó, in the Pyrenean valley of Cerdanya. Most of the Magdalenian sites have yielded information about short or seasonal occupations related with the exploitation of natural resources. Parco cave preserves a good stratigraphic sequence ranging from middle to upper and late Magdalenian (from 15th to 13th millennium BP). In this site, various human activities were organized around a significant number of hearths. They were related with animal and mineral processing. The data obtained at
The Song Hong (Red River) Delta, northern Vietnam, is characterized by huge natural levees in an area of the delta plain known as the West Floodplain, where fluvial sedimentation predominates. The natural levee along the Day River, a major distributary of the Song Hong, is larger than that of the main course of the Song Hong. The Day River levee is 3–8 km wide and rises 3–5 m above the adjacent back swamps. By providing a closed polder embankment system, the levee has played an important role in human settlements since the late Metal age. We reconstructed the Holocene evolution of the Day River natural levee in relation to eustatic sea-level change, delta progradation, and the distribution of archaeological sites. During the early Holocene, the accumulation of sediment discharged by the Song Hong enhanced both aggradation of the natural levee and river-mouth progradation within the drowned valley of the Song Hong. Radiocarbon dates obtained from cores, outcrops, and archeological sites
Abstracts / Quaternary International 279-280 (2012) 121–232
generated by the 1498 Meio earthquake (M8.2-8.4) that occurred along the Nankai Through, on the coastal-fluvial evolution of the area. This research is of geoarchaeological value as historical sources document the sudden decline at the end of the 15th century of an important harbour town, Hashimoto, located along the Hamana river. This river connected the Pacific Ocean with a coastal embayment closed by a sand barrier (i.e. the present-day called Hamana lake) before the 15th century. The reconstruction of the palaeocourse of the Hamana river was carried out on the basis of detailed facies analyses of undisturbed sediment cores (geoslicer and drilling). This palaeochannel was detected along the western side of the present-day Hamana coastal embayment. It seems that due to the Meio Tsunami, its mouth became abruptly closed due to the migration of huge volumes of sand initiating the development of a marsh environment upstream along the channel. Moreover, it is known that due to the 1498 Meio tsunami, the Hamana back-barrier sheltered environment became again connected to the Pacific Ocean due to breaching of the sand barrier. Both environmental changes are synchronous with the sudden decline of the harbour town Hashimoto. These data suggest that the breaking off of the water route connecting the harbour town Hashimoto and Pacific Ocean potentially led to the decline of the harbour. CHANGES IN 230TH-NORMALIZED FLUX OF BIOGENIC COMPONENTS RECORDED IN THE SOUTH CHILEAN MARGIN OVER THE PAST 13,000 YEARS Miho Fukuda. University of Tsukuba, Japan E-mail address: [email protected]
During the last glacial maximum, the atmospheric partial pressure of CO2 (pCO2atm) was quite low, 180 ppm and rapidly increased to 280 ppm during the last deglacation (Monnin et al., 2001). Although the biological pump is one of the sinks of pCO2atm, how much biological pump had contributed to the atmospheric pCO2 reduction throughout the deglaciation? Its evaluation is still insufficient. The aims of this study is to understand the temporal changes of Thorium-230 (230Th)-normalized export fluxes of biogenic materials, namely biogenic components, total organic carbon (TOC), total nitrogen (TN) and biogenic opal (Opal), which are commonly utilized as proxies for productivity, recorded in a sediment core (PC3) collected near the mouth of Strait of Magellan, Pacific side (52 S). When 230 Th was born to decay of dissolved Uranium-234 (234U) in the seawater, it is promptly scavenged by adsorption on settling particles with a short residence time (w 40 years). The 230Th-normalization method is based on the assumption that the flux of scavenged 230Th reaching the seafloor is known and equal to the rate of 230Th production from the decay of 234U in the overlying water column. Furthermore, 230Th input associated with terrigenous materials can be corrected by 232Th activity. The 230Thnormalized fluxes of TOC, TN and biogenic Opal during the Younger Dryas (YD) were 30%, 40% and 60% higher than those during the Holocene, respectively. Biogenic opal flux is a proxy of relative strength of upwelling. High values of TOC, TN, and Opal during the YD suggest relatively high marine productivity and biological pump due to enhanced upwelling rather than that during the Holocene. THE MAGDALENIAN IN NE IBERIA
Parco and Montlleó sites have enabled the reconstruction of the Tardiglacial palaeoenvironment for the southeastern Pyrenees area. However, other sites from the southern part of the country are also providing very interesting information about climate, as well as faunal and floral elements. Some malacological remains found in Montlleó come from the Mediterranean coast, but others come from the Cantabrian area, thus opening a new route of connection between both seas during the Magdalenian. We have also a few artistic evidences comes from Taverna cave, Parellada IV, Fornols Haut and Molí del Salt sites. One of the most significant findings of our research is the archaeological confirmation of the existence of a mountain pass across the Pyrenees during the Magdalenian. Some raw materials found in Montlleó are from French origin, others come from the southern slopes of the Pyrenees, and other ones could come from either side. The site is near the most western path opened during the last glaciation for crossing the Pyrenees. Thus, people and materials may well have circulated across the Pyrenees through this corridor. TEMPORAL CHANGE OF THE LATE PLEISTOCENE–HOLOCENE BARRIERLAGOON COMPLEX OF THE ECHIGO PLAIN, CENTRAL JAPAN Ayako Funabiki. Geological Survey of Japan, Japan E-mail address: [email protected]
The depositional history of the barrier-lagoon systems of the Echigo Plain, central Japan, was investigated using more than 10,000 borehole logs and 27 radiocarbon dated cores. The combined effect of sea-level rise during the last deglacial, sediment discharge from the Shinano and Agano Rivers, and subsidence in the Echigo Plain Western Margin Fault Zone resulted in deposition of a 160-m-thick incised valley fill sequence, barrier-lagoon systems, and two marine flooding surfaces. The coastline of the plain is about 80 km long and there are three barrier systems. The oldest marine flooding surface was dated at around 9 cal kyr BP, when sea level rose rapidly, marked by a change from a tidal marsh environment to an inner bay or offshore environment. This environmental change manifested as a ravinement surface in some borehole data and was recognized up to 10 km landward. The first barrier-lagoon system formed during 9–8 cal kyr BP. In the southern Echigo plain, this system was succeeded by the second and third barrier-lagoon systems, which developed in response to subsidence in the Echigo Plain Western Margin Fault Zone. However, in areas distant from the fault system, only one barrier-lagoon system was developed. The second marine flooding surface formed during 8–7 cal kyr BP and caused the most extensive incursion of brackish water into the lagoonal area. This age corresponds to that of the maximum flooding surface of the Echigo Plain identified in previous studies (e.g., Omura et al., 2006). The second marine flooding was followed by seaward progradation of the second, and then the third, barrier-lagoon systems. The Echigo Plain is still subsiding at about 3 mm/yr, as indicated by the dip of the marine flooding surfaces towards the thalweg of paleo-River. HOLOCENE EVOLUTION OF NATURAL LEVEES OF THE SONG HONG (RED RIVER) DELTA, NORTHERN VIETNAM Ayako Funabiki. Geological Survey of Japan, Japan E-mail address: [email protected]
José María Fullola. SERP Universitat de Barcelona, Spain E-mail address: [email protected]
The Magdalenian is the first Upper Palaeolithic period to show a widespread human occupation along the northeastern territories of Iberia. Several sites have been located across the plains and mountains extending from the Pyrenean valleys of the Segre River to the mouth of the Ebro River. The oldest dates (17th millennium BP) were obtained at the open-air site of Montlleó, in the Pyrenean valley of Cerdanya. Most of the Magdalenian sites have yielded information about short or seasonal occupations related with the exploitation of natural resources. Parco cave preserves a good stratigraphic sequence ranging from middle to upper and late Magdalenian (from 15th to 13th millennium BP). In this site, various human activities were organized around a significant number of hearths. They were related with animal and mineral processing. The data obtained at
The Song Hong (Red River) Delta, northern Vietnam, is characterized by huge natural levees in an area of the delta plain known as the West Floodplain, where fluvial sedimentation predominates. The natural levee along the Day River, a major distributary of the Song Hong, is larger than that of the main course of the Song Hong. The Day River levee is 3–8 km wide and rises 3–5 m above the adjacent back swamps. By providing a closed polder embankment system, the levee has played an important role in human settlements since the late Metal age. We reconstructed the Holocene evolution of the Day River natural levee in relation to eustatic sea-level change, delta progradation, and the distribution of archaeological sites. During the early Holocene, the accumulation of sediment discharged by the Song Hong enhanced both aggradation of the natural levee and river-mouth progradation within the drowned valley of the Song Hong. Radiocarbon dates obtained from cores, outcrops, and archeological sites