- Email: [email protected]
From terrestrial remote sensing to morphotectonics: Hard rock scarps on the Island of Crete, Greece
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Abstracts / Quaternary International 279-280 (2012) 462–565
PRE-COLUMBIAN HUMAN LAND-USE AND IMPACT IN THE BOLIVIAN AMAZON Bronwen Whitney. School of Geosciences, The University of Edinburgh, United Kingdom E-mail address: [email protected]
In recent years, mounting evidence of prehistoric human activity, such as large earthworks and terra preta soils has challenged the ‘virgin wilderness’ paradigm of Amazonia, pointing to larger scale impact of preColumbian societies. However, there is intense debate over the geographic scale of these impacts and their ecological legacy, in particular, whether pre-1492 Amazonia was an intensively managed ‘cultural parkland’. We incorporate palaeoecological and archaeological approaches to quantify the pre-Columbian human land-use and impact in the Bolivian Amazon. Our study focuses on the Llanos de Moxos; a patchwork landscape dominated by seasonally-flooded savannahs interspersed with forested mounds and river levées, and characterized by large-scale pre-Columbian earthworks such as raised fields, habitation mounds, and canals. We explore prehistoric human impact on tropical ecosystems through fossil pollen and charcoal analyses of sediment cores extracted from lakes located adjacent to several large habitation mounds in the Casarabé area of the eastern Llanos de Moxos, occupation of which occurred between ca. AD 400 and 1500. Key forest and savannah indicators are used to determine the extent of pre-Columbian landscape alteration, as well as ecosystem change following indigenous population decline after AD 1492. We also explore the degree to which the floristic composition of forest was selectively altered to favour economically-important taxa, drawing on the results of phytolith and starch grain analysis of ceramics to determine what plant species were processed for food. FROM TERRESTRIAL REMOTE SENSING TO MORPHOTECTONICS: HARD ROCK SCARPS ON THE ISLAND OF CRETE, GREECE Thomas Wiatr. RWTH Aachen, Germany E-mail address: [email protected]
Greece has over 2500 island including Crete in the south of the Aegean region is the biggest one. The development of a multidirectional tectonic regime on the Island of Crete is interpreted as a result of the Hellenic subduction in the south and the westward extrusion of the Anatolian plate in the north. Rapid uplift of w1,2 mm/a (Meulenkamp et al., 1994) can be observed on the entire island. During the field campaign in spring 2010 five different limestone escarpments of normal faults were mapped and scanned with a terrestrial LiDAR in Central Crete. A complex pattern of normal faulting and possible active faults in different limestones formations have been studied. The natural fault planes of the scarp surfaces host important indices for identifying the relative slip age: 1) change of roughness from bottom to top, 2) different exhumed weathering stages, and 3) the fault geomorphology. For the estimating the seismicity of the individual faults we used the backscattered signal of the laser beam, the geomorphological geometry and the fault plane conditions. The range of the point to point scale is between 2 mm and several centimetres. We were able to reconstruct the scarp surface in 3D with the help of a high resolution digital elevation model and the backscattered signal is also reported the surface conditions. LATE PLEISTOCENE AND HOLOCENE HYDROLOGICAL VARIABILITY OF THE INDO-PACIFIC WARM POOL: A LACUSTRINE PERSPECTIVE Satrio A. Wicaksono. Brown University, United States E-mail address: [email protected]
Lake Matano (2 29.7’S 12120.0’E) in south-central Sulawesi is the eight deepest lake in the world and lies at the heart of the tropical Indo-Pacific Warm Pool (IPWP), the largest pool of warmest surface seawaters on Earth. Convective activity in this region is intimately linked with the AsianAustralian Monsoon (AAM) and the El Niño/La Niña-Southern Oscillation (ENSO), both fundamental and complex climatic systems with high societal impacts. Our incomplete knowledge of the history of these systems and their impacts on the hydrology of the IPWP is due to limited proxy records, often confounded with contradictory interpretations in past
studies. In light of this uncertainty, this study provides continuous, multiproxy records of hydrological variability from Lake Matano spanning Marine Isotope Stage 3 to present. Analyses of multiple piston cores from Lake Matano suggest that changes in magnetic susceptibility and atomic C/ N ratio correlate and jointly record dry/wet transitions; increases in magnetic susceptibility generally reflect higher terrigenous inputs and periods with predominantly longer rainy seasons. We will present millennial-scale terrestrial IPWP hydrologic variability data throughout Late Pleistocene and Holocene, associated with coupled changes in ENSO, AAM, and the location of the Intertropical Convergence Zone (ITCZ). NEW MOLECULAR MARKER AND SPECTROSCOPIC TOOLS FOR RECONSTRUCTING WILDFIRE HISTORY FROM SEDIMENTARY RECORDS Daniel B. Wiedemeier. University of Zurich, Switzerland E-mail address: [email protected]
Late Quaternary wildfire reconstruction has mainly been based on dated lake sediment cores, where the number of microscopically detected charcoal particles has served as the raw data for assessing the past fire frequency. Quantifying (microscopically) visible charcoal may reflect the relatively large and structurally sound charcoal particles from forest fires. However, this technique is less likely to quantify smaller charcoal fractions derived from grasses – probably the main contributor of charcoal in savannas and open grassy woodlands. Therefore, we are developing a new methodology to infer past wildfires from lacustrine sediments by using geochemical tools. Such geochemical methods could assess the whole size range of charred fire residues in sedimentary records and could yield additional information about the burned vegetation when only microscopically invisible fire residues are present. In particular, we are adapting a geochemical marker method (benzene polycarboxylic acids (BPCA)) for this task. BPCA have been used for almost a decade as unambiguous molecular markers for the presence of fire-derived organic matter in soil, and in a recent laboratory ring trial have been proven to be a robust tool for the quantification of charred fire residues. In order to calibrate and validate the BPCA method for sedimentological fire reconstruction, we use well characterized lake sediment cores from Australia. They exhibit distinct wildfire histories (charcoal counting method) – data, that can be compared to the results of the BPCA method. In addition, we are examining these cores with MIR-PLS (Mid InfraRed spectroscopy with Partial Least Square analysis), which is another geochemical method that can detect charred organic material independent of its particle size. We are using it as a screening method to locate interesting sections of the cores and it should provide another dataset of fire residue contents, to which the subsequent BPCA analysis can be compared. 40
AR/39AR GEOCHRONOLOGY OF HOLOCENE BASALTS; EXAMPLES FROM STROMBOLI, ITALY Jan Wijbrans. VU University, Faculty of Earth and Life Sciences, Netherlands
E-mail address: [email protected]
Absolute chronologies of active volcanoes and consequently timescales for eruptive behaviour and magma production form a quantitative basis for understanding the risk of volcanoes. Surprisingly, the youngest records in the geological timescale often prove to be the most elusive when it comes to isotopic dating. Absolute Holocene volcanic records almost exclusively rely on 14C ages measured on fossil wood or other forms of biogenic carbon. However, on volcanic flanks, fossil carbon is often not preserved, and of uncertain origin when present in paleosols. Also, low 14C-volcanic CO2 may have mixed with atmospheric and soil 14C-CO2, potentially causing biased ages. Even when reliable data are available, it is important to have independent corroboration of inferred chronologies as can be obtained in principle using the 40K/40Ar decay system dating the volcanic products. Here we present results of a 40Ar/39Ar dating study of basaltic groundmass in the products from the Pleistocene – Holocene boundary until the beginning of the historic era for the north-northeastern flank of Stromboli, Aeolian Islands, Italy, identifying a short phase of intensified flank effusive activity 7500500 yrs ago, and a maximum age of 4000900 yr for the last flank collapse event that might have caused the
Abstracts / Quaternary International 279-280 (2012) 462–565
PRE-COLUMBIAN HUMAN LAND-USE AND IMPACT IN THE BOLIVIAN AMAZON Bronwen Whitney. School of Geosciences, The University of Edinburgh, United Kingdom E-mail address: [email protected]
In recent years, mounting evidence of prehistoric human activity, such as large earthworks and terra preta soils has challenged the ‘virgin wilderness’ paradigm of Amazonia, pointing to larger scale impact of preColumbian societies. However, there is intense debate over the geographic scale of these impacts and their ecological legacy, in particular, whether pre-1492 Amazonia was an intensively managed ‘cultural parkland’. We incorporate palaeoecological and archaeological approaches to quantify the pre-Columbian human land-use and impact in the Bolivian Amazon. Our study focuses on the Llanos de Moxos; a patchwork landscape dominated by seasonally-flooded savannahs interspersed with forested mounds and river levées, and characterized by large-scale pre-Columbian earthworks such as raised fields, habitation mounds, and canals. We explore prehistoric human impact on tropical ecosystems through fossil pollen and charcoal analyses of sediment cores extracted from lakes located adjacent to several large habitation mounds in the Casarabé area of the eastern Llanos de Moxos, occupation of which occurred between ca. AD 400 and 1500. Key forest and savannah indicators are used to determine the extent of pre-Columbian landscape alteration, as well as ecosystem change following indigenous population decline after AD 1492. We also explore the degree to which the floristic composition of forest was selectively altered to favour economically-important taxa, drawing on the results of phytolith and starch grain analysis of ceramics to determine what plant species were processed for food. FROM TERRESTRIAL REMOTE SENSING TO MORPHOTECTONICS: HARD ROCK SCARPS ON THE ISLAND OF CRETE, GREECE Thomas Wiatr. RWTH Aachen, Germany E-mail address: [email protected]
Greece has over 2500 island including Crete in the south of the Aegean region is the biggest one. The development of a multidirectional tectonic regime on the Island of Crete is interpreted as a result of the Hellenic subduction in the south and the westward extrusion of the Anatolian plate in the north. Rapid uplift of w1,2 mm/a (Meulenkamp et al., 1994) can be observed on the entire island. During the field campaign in spring 2010 five different limestone escarpments of normal faults were mapped and scanned with a terrestrial LiDAR in Central Crete. A complex pattern of normal faulting and possible active faults in different limestones formations have been studied. The natural fault planes of the scarp surfaces host important indices for identifying the relative slip age: 1) change of roughness from bottom to top, 2) different exhumed weathering stages, and 3) the fault geomorphology. For the estimating the seismicity of the individual faults we used the backscattered signal of the laser beam, the geomorphological geometry and the fault plane conditions. The range of the point to point scale is between 2 mm and several centimetres. We were able to reconstruct the scarp surface in 3D with the help of a high resolution digital elevation model and the backscattered signal is also reported the surface conditions. LATE PLEISTOCENE AND HOLOCENE HYDROLOGICAL VARIABILITY OF THE INDO-PACIFIC WARM POOL: A LACUSTRINE PERSPECTIVE Satrio A. Wicaksono. Brown University, United States E-mail address: [email protected]
Lake Matano (2 29.7’S 12120.0’E) in south-central Sulawesi is the eight deepest lake in the world and lies at the heart of the tropical Indo-Pacific Warm Pool (IPWP), the largest pool of warmest surface seawaters on Earth. Convective activity in this region is intimately linked with the AsianAustralian Monsoon (AAM) and the El Niño/La Niña-Southern Oscillation (ENSO), both fundamental and complex climatic systems with high societal impacts. Our incomplete knowledge of the history of these systems and their impacts on the hydrology of the IPWP is due to limited proxy records, often confounded with contradictory interpretations in past
studies. In light of this uncertainty, this study provides continuous, multiproxy records of hydrological variability from Lake Matano spanning Marine Isotope Stage 3 to present. Analyses of multiple piston cores from Lake Matano suggest that changes in magnetic susceptibility and atomic C/ N ratio correlate and jointly record dry/wet transitions; increases in magnetic susceptibility generally reflect higher terrigenous inputs and periods with predominantly longer rainy seasons. We will present millennial-scale terrestrial IPWP hydrologic variability data throughout Late Pleistocene and Holocene, associated with coupled changes in ENSO, AAM, and the location of the Intertropical Convergence Zone (ITCZ). NEW MOLECULAR MARKER AND SPECTROSCOPIC TOOLS FOR RECONSTRUCTING WILDFIRE HISTORY FROM SEDIMENTARY RECORDS Daniel B. Wiedemeier. University of Zurich, Switzerland E-mail address: [email protected]
Late Quaternary wildfire reconstruction has mainly been based on dated lake sediment cores, where the number of microscopically detected charcoal particles has served as the raw data for assessing the past fire frequency. Quantifying (microscopically) visible charcoal may reflect the relatively large and structurally sound charcoal particles from forest fires. However, this technique is less likely to quantify smaller charcoal fractions derived from grasses – probably the main contributor of charcoal in savannas and open grassy woodlands. Therefore, we are developing a new methodology to infer past wildfires from lacustrine sediments by using geochemical tools. Such geochemical methods could assess the whole size range of charred fire residues in sedimentary records and could yield additional information about the burned vegetation when only microscopically invisible fire residues are present. In particular, we are adapting a geochemical marker method (benzene polycarboxylic acids (BPCA)) for this task. BPCA have been used for almost a decade as unambiguous molecular markers for the presence of fire-derived organic matter in soil, and in a recent laboratory ring trial have been proven to be a robust tool for the quantification of charred fire residues. In order to calibrate and validate the BPCA method for sedimentological fire reconstruction, we use well characterized lake sediment cores from Australia. They exhibit distinct wildfire histories (charcoal counting method) – data, that can be compared to the results of the BPCA method. In addition, we are examining these cores with MIR-PLS (Mid InfraRed spectroscopy with Partial Least Square analysis), which is another geochemical method that can detect charred organic material independent of its particle size. We are using it as a screening method to locate interesting sections of the cores and it should provide another dataset of fire residue contents, to which the subsequent BPCA analysis can be compared. 40
AR/39AR GEOCHRONOLOGY OF HOLOCENE BASALTS; EXAMPLES FROM STROMBOLI, ITALY Jan Wijbrans. VU University, Faculty of Earth and Life Sciences, Netherlands
E-mail address: [email protected]
Absolute chronologies of active volcanoes and consequently timescales for eruptive behaviour and magma production form a quantitative basis for understanding the risk of volcanoes. Surprisingly, the youngest records in the geological timescale often prove to be the most elusive when it comes to isotopic dating. Absolute Holocene volcanic records almost exclusively rely on 14C ages measured on fossil wood or other forms of biogenic carbon. However, on volcanic flanks, fossil carbon is often not preserved, and of uncertain origin when present in paleosols. Also, low 14C-volcanic CO2 may have mixed with atmospheric and soil 14C-CO2, potentially causing biased ages. Even when reliable data are available, it is important to have independent corroboration of inferred chronologies as can be obtained in principle using the 40K/40Ar decay system dating the volcanic products. Here we present results of a 40Ar/39Ar dating study of basaltic groundmass in the products from the Pleistocene – Holocene boundary until the beginning of the historic era for the north-northeastern flank of Stromboli, Aeolian Islands, Italy, identifying a short phase of intensified flank effusive activity 7500500 yrs ago, and a maximum age of 4000900 yr for the last flank collapse event that might have caused the