The paper presents proxies from an interdisciplinary geoarchaeological working group. Sediment analyses and geomorphological studies, radiocarbon ages of snail shells and luminescence dating of loess allow a preliminary chronology of the environmental evolution of the eastern Atacama desert, Nazca–Palpa region (southern Peru). Until now, typical desert loess was unknown from the arid western flank of the Andes (southern Peru). The loess points to periods of more humid conditions with open grasslands at the eastern Atacama desert margin in the early and middle Holocene. In the footzone of the Andes, aridification set in before the Paracas Culture (c. 800–200 bc) evolved, but the Cordillera Occidental remained semi‐arid. A second push of increasing aridity started at the latest in the Middle Nazca Period (after ad 250). During this time, the Nazca settlement centres moved upstream through the river oasis, following the eastward‐shifting desert margin. It is possible that culminating aridity after ad 600 caused the collapse of the Nazca civilization. During the Late Intermediate Period (ad 1000–1400), more humid conditions favoured the massive reoccupation of the eastern Atacama up to a distance of about 40 km from the Pacific coast. Since the 14th and 15th centuries, the Palpa region has again been part of the hyper‐arid Atacama. The study shows that in the Nazca–Ica region, the deep cultural changes of Pre‐Columbian civilizations were not caused by catastrophic run‐off of El Niño events, but by a shifting eastern desert margin due to the changing monsoonal influence.
Buried or refilled archaeological ditches offer great opportunities in terms of reconstructing past human activities and human-nature interactions. The Early Bronze Age settlement of Fidvár in southwestern Slovakia offers excellent opportunities for this kind of geoarchaeological study. Based on previous magnetic prospection further geophysical, sedimentological and geochemical investigations were carried out focusing on the three existing semi-elliptical early Bronze Age ditches. Afterwards an appropriate assortment of methods was chosen and successfully applied to two of the ditches in order to reconstruct their lateral and vertical geometries. Alongside interesting archaeological outcomes for the Fidvár site our results highlight the advantageous combination of geophysical and geochemical data. Only this multimethodological approach allowed both a universal and precise reconstruction of the archaeological features.
Population estimates are a vital backdrop to our understanding of ancient societies' socio‐economic structures and development. In order to facilitate such an informational mise en scène in terms of the early Bronze Age settlement of Fidvár in southwestern Slovakia, a new geophysical–geochemical approach is presented here, the first results of which are very promising. The crux of the new methodology utilizes the population's chemical fingerprint in relation to total anthropogenic phosphorus input as a proxy for different population models. These methods suggest an early Bronze Age population of 300–600 individuals, in accordance with the comparative analysis of a magnetic survey, and also matches initial archaeological estimates. Further methodological adjustments suggest an even higher population of up to 1000 inhabitants. In light of these figures, it is likely that Fidvár was one of the centres of the early Bronze Age socio‐economic system of the northern Pannonian Basin. Copyright © 2013 John Wiley & Sons, Ltd.
Change analysis of rock glaciers is crucial to analyzing the adaptation of surface and subsurface processes to changing environmental conditions at different timescales because rock glaciers are considered as potentially unstable slopes and solid water reservoirs. To quantify surface change in complex surface topographies with varying surface orientation and roughness, a full three‐dimensional (3D) change analysis is required. This study therefore proposes a novel approach for accurate 3D point cloud‐based quantification and analysis of geomorphological activity on rock glaciers. It is applied to the lower tongue area of the Äußeres Hochebenkar rock glacier, Ötztal Alps, Austria. Multi‐temporal and multi‐source topographic LiDAR data are used to quantify surface changes and to reveal their spatial and temporal characteristics at different timescales within the period 2006–2018. LiDAR‐based examinations are complemented with subsurface characteristics obtained from electrical resistivity tomography. This combined approach reveals active and variable spatial and temporal surface dynamics in the investigated area, with minimum detectable change between 0.09 and 0.65 m at 95% confidence. Given that this approach overcomes current uncertainties in established methods of differentiating complex rock glacier surfaces, we consider it a valuable addition that can be applied to objects of similar properties such as landslides or glaciers.
Abstract. Topographic change at a given location usually results from multiple processes operating over different timescales. However, interpretations of surface change are often based upon single values of movement, measured over a specified time period or in a single direction. This work presents a method to help separate surface change types that occur at different timescales related to the deformation of an active rock glacier, drawing on terrestrial lidar monitoring at sub-monthly intervals. To this end, we derive 3D topographic changes across the Äußeres Hochebenkar rock glacier in the Ötztal Alps. These changes are presented as the relative contribution of surface change during a 3-week period (2018) to the annual surface change (2017–2018). They are also separated according to the spatially variable direction perpendicular to the local rock glacier surface (using point cloud distance computation) and a single main direction of rock glacier flow, indicated by movement of individual boulders. In a 1500 m2 sample area in the lower tongue section of the rock glacier, the contribution of the 3-week period to the annual change perpendicular to the surface is 20 %, compared with 6 % in the direction of rock glacier flow. Viewing change in this way, our approach provides estimates of surface change in different directions that are dominant at different times of the year. Our results demonstrate the benefit of more frequent lidar monitoring and, critically, the requirement for novel approaches to quantifying and disaggregating surface change, as a step towards rock glacier observation networks focusing on the analysis of 3D surface change over time.
Age and origin of ancient famous Karez water systems in the oases of the Turpan Basin are open questions in geoarchaeological and historical research. Four hypotheses exist: (a) invention during Han dynasty more than 2000 years ago, (b) transfer of technology from Persian Qanat's more than 3000 years ago, (c) independent invention of local Uyghur people in the 15th century, and (d) late invention during the Chinese Qing dynasty (19th century). Our study dates, for the first time, 8 Karez systems by 14 C from plants buried during the formation of Karez mounds, and interviews in order to record oral tradition. We found that the oldest investigated Karez systems originated in the Uyghurian Huihe dynasty (790-1755 AD), which coincides with the oral tradition. A second phase may have occurred during late Huihe/Qing dynasty (after 1755 AD), which may explain why information and the Uygurian term "Kan er jing" went down in historic Chinese records. In conclusion, hypothesis (d) that oldest Karez systems were built during Qing dynasty has to be rejected because they are at least 600 years old. Instead, during the 3rd Chinese expansion in the 19th century AD the Karez system expanded and got maintenance. A review of regional palaeoclimatic proxies suggests that the origin and the maintenance of the Karez systems took place rather in more humid periods than in more arid ones. However, more research is needed on other Karez systems to test the pending hypotheses of a much older age.
A multi‐method research design based on terrestrial laser scanning, GIS, geophysical prospecting (electrical resistivity tomography, refraction seismics) and sedimentology is applied for the first time to investigate enclosed karst depressions in an integrated way. Fusing multi‐resolution surface and subsurface geodata provides profound insights into the formation, geometry and geomorphologic processes of dolines. The studied landforms, which are located in the Dikti Mountains of East Crete, are shown to be filled by loose sediments of thicknesses of up to 30 m that mainly consist of fine‐grained material overlying solid bedrock at depths below 35 to 45 m. By combining subsurface observations with geomorphometric calculations, local doline genesis can be traced back to initial collapse of fractured bedrock followed by subsequent infilling with colluvials. In order to define crucial methodological requirements and guidelines for data fusion, both the impact of different elevation models and the influence of data resolution are assessed. Surface volumes of depressions derived by the digital surface model are 7–21% higher than the results obtained from the terrain model due to vegetation. Similarly, estimates of infill volume calculated on the basis of geophysical outcomes and elevation data differ by up to 13%. Calculations of the landforms' current volumes (i.e. total surface and subsurface volume), however, are fairly insensitive to raster resolution. Hence, the distinct geomorphologic properties of landforms (e.g. shape, terrain roughness, slope inclination) substantially determine the geomorphometric analysis of both surface and subsurface data. As shown by the findings, data fusion to integrate digital terrain, geophysical and sedimentological datasets of varied resolutions benefits geomorphologic studies and helps provide a comprehensive image of landforms. Copyright © 2013 John Wiley & Sons, Ltd.
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