ABSTRACT The construction history and subsequent usage of burial mounds are an important testimony for socio‐economic transformation in prehistoric societies. The Baalberge–Schneiderberg burial mound, subject of the presented study, falls in this category as it is considered as an important monument that indicates the emergence of early social stratification during the Chalcolithic period in central Europe. This hypothesis relies on the chronological development of the burial mound, which is not fully understood until now. Therefore, a reconstruction of the complex stratigraphy of the burial mound including construction phases and later alterations is highly relevant for archaeological research, but the required excavations would be onerous and inconsistent with preservation efforts. In this paper, we demonstrate that non‐invasive geophysical prospection, especially seismic sounding with shear and Love waves, is suitable to obtain the required stratigraphic information, if seismic full waveform inversion (FWI) and reflection imaging are applied. Complementary information on the preservation state of the mound is obtained through Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EMI) measurements. To support the seismic and geoelectric results, we utilize Dynamic Testing (DynP), geoarchaeological corings, 14 C‐Dating and archaeological records. Our investigations reveal two construction phases of the Baalberge–Schneiderberg mound. The 14 C‐Dating yields dates for the older burial mound that are contemporary to the Chalcolithic Baalberge group (4000–3400 bc ). During the Early Bronze Age (EBA), the mound was enlarged to its final size by people of the Aunjetitz/Únětice society (2300–1600 bc ). However, both seismic and geoelectric depth sections show an extensive disturbance of the original stratigraphy due to former excavations. For this reason, the exact shape of the older burial mound cannot be determined exactly. Based on our data, we estimate that its height was below 2 m. In consequence, the original Baalberge burial mound was less monumental as until now assumed, which potentially prompting a revision of its significance as indicator for social differentiation.
In contrast to frictional faults and cataclasites in well consolidated and cemented sediments, lithologies with little or no diagenetic consolidation and high porosity develop deformation band type faults. Generally, deformation bands often form in well sorted fine to medium-grained sandstones before major porosity loss during diagenesis. These deformation structures were studied at the Eastern border of the Eisenstadt Basin where deformation bands were found in Neogene calcarenites of the Leithakalk formation in a quarry near St. Margarethen (Eastern Austria). The Badenian Leithakalk in the quarry mainly comprises bioclasts dominated by corallinacean debris and foraminifera. The orientation of the deformation bands indicates E-W directed extensional kinematics which can be correlated to large scale horst-and-graben structures within the underlying basement and lower Miocene sedimentary rocks. Generally, the Leithakalk shows a primary porosity of around 25%, but within the deformation bands the porosity is reduced to 1%, showing no observable cataclastic grain size reduction. A 3x3.5cm sized drill core containing a deformation band was analyzed using X-ray micro-tomography with a spatial resolution of 70 microns. The pores outside the deformation band are 500-2000 microns in diameter, and show a well connected pore space. In contrast, the size of pores is strongly reduced within the deformation band to a maximum of 100 microns; the pores are clearly isolated and fill < 1 % of the volume. Furthermore, the permeability across selected deformation bands was measured with a minipermeameter. The deformation bands itself has almost zero permeability due to the decreased porosity. The permeability is 50-100 times reduced in contrast to the undeformed rock fabric. Thin section analysis of the same samples revealed a significantly lower amount of carbonatic cement within the deformation bands than in the undeformed limestone. However, no fracturing of bioclastic particles or cement grains could be observed. Therefore we conclude that the deformation bands formed before the cementation of the Leithakalk.
<p>Detailed knowledge on the temporal and spatial distribution of faults and fractures not only reveals the geodynamic and tectonic evolution of the lithosphere. It is also of increasing importance with regard to economic, social, and environmental challenges such as nuclear waste disposal, gas storage, geothermal energy, natural hazards, and mineral resource exploration. In this context reliable data on both timing and kinematics of deformation and their regional impact on faulting and fracture formation provide crucial information to evaluate exploration, storage, and production risks, which in turn stresses the need for comprehensive data on paleostress fields and their influence on deformation, fault reactivation, fluid activity, and hydrothermal mineralization.</p><p>In this study we present a first comprehensive approach to compile and visualize information on the crustal paleostress field of Central Europe with a focus on northern Bavaria and adjacent areas. The compilation includes published structural data from kinematic paleostress analyses (e.g. fault-slip analysis, tectonic stylolites) and geo- and thermochronological ages of fracture mineralization and fault activity, respectively. The present compilation comprises structural records from more than 40 studies and age information from more than 100 geo-thermochronological studies. All structural data are categorized according to its tectonic stress regime and quality-ranked for reliability and comparability. The consequent linkage of structural data with thermochronological data wherever possible allows to correlate local paleostress fields and deformation patterns with regional to global tectonic events. As one result, the &#8220;Paleostress Chart for Northern Bavaria and adjacent Areas&#8221; visualizes the temporal and spatial evolution of several regions in Central Europe together with known tectonic phases, sedimentary unconformities and the plate kinematic framework since the Carboniferous.</p><p>This compilation may therefore help to better understand the timing and the spatio-temporal evolution of crustal stress patterns for tectonic events across Central Europe in the context of plate tectonics.&#160;</p><p>We aim to supplement and improve existing paleostress models on both, regional, and temporal scale by compiling published and original data. In the long term the database is intended as a continuing compilation where data from all across Central Europe are supposed to be included and refined subsequently.</p>
<p>The Franconian Basin in SE Germany has seen a complex stress history indicative of several extensional and compressional phases e.g. the Iberia-Europe collision acting on a pre-faulted Variscan basement. Early Cretaceous extension is followed by Late Cretaceous inversion with syntectonic sedimentation and deformation increasing progressively from SW to NE culminating in the Franconian Line where basement rocks are thrusted over the Mesozoic cover. The development of this intracontinental fold-and-thrust belt is followed by Paleogene extension associated with the formation of the Eger Graben, which is then succeeded by a new compressional event as a consequence of the Alpine orogeny.</p><p>We use existing data from literature and geological maps and new field data to construct balanced cross-sections in order to reveal the architecture of the Cretaceous fold-and-thrust belt. In addition, we undertake paleostress analysis using a combination of fault slip information, veins and tectonic and sedimentary stylolites to identify stress events in the study area, as well as their nature and timing. Furthermore, we try to understand how basement faults influence younger faults in the cover sequence.</p><p>Our paleostress data indicates that at least five different stress events existed in Mesozoic to Cenozoic times (from old to young): (1) an N-S directed extensional stress field with E-W striking normal faults, (2) a NNE-SSW directed compressional stress field causing thrusting and folding of the cover sequence, (3) a strike slip regime with NE-SW compression and NW-SE extension, (4) an extensional event with NW-SE extension and the formation of ENE-WSW striking faults according to the formation of the Eger Graben in the E, and finally (5) a strike slip regime with NW-SE compression and NE-SW extension related to Alpine stresses. The geometry of faulting and deformation varies significantly over the regions with respect to the influence of and distance to inherited Variscan structures.</p><p>We argue that the extensional event of stress field (1) provides spacing for Early Cretaceous sedimentation in the Franconian Basin. This is followed by the creation of an intracontinental fold-and-thrust belt during stress fields (2) and (3) with a slight rotation of the main compressive stress during these events in Late Cretaceous. We associate the following extension to the development of the Eger Graben in Miocene time. Finally, a NW-SE directed compression related to Alpine stresses in an intracontinental strike-slip regime is following. Reconstruction of the Cretaceous fold-and-thrust belt reveals mainly fault propagation folding with deep detachments sitting below the cover sequence indicating thick-skinned tectonics. We argue that the Franconian Line is a thrust with a steeply dipping root that belongs to the same fold-and-thrust belt.</p>
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