Using archaeological and geomorphological evidence for the establishment of a relative chronology and evolution pattern for Holocene landslides

Abstract

Hilly regions around the world are one of the most vulnerable places for inhabitation, where landslides represent a permanent threat for their population. In some particular cases, in the past, due to their topographic features, areas affected by massive landslides served a real opportunity for the location of strategic and fortified settlements. In this study, we have extended a previous approach of correlation between landslides and archaeological heritage, adding 14 new representative case studies of landslided hillforts, a new period with landslided hillforts, and a new typology of relationship (landslided tumuli) for establishing relative chronologies for landslide inventories. The landslide mapping presented here supplements a previous inventory, which now has 1211 landslides, and it is based on the interpretation of high-resolution DEMs, geomorphometric derivatives, remote sensing images, and field validation. For one of the most characteristic sites (Băiceni settlement, Iaşi County), we used Electrical Resistivity Tomography (ERT) to assess the geometry of the compound and complex landslides. The current approach allowed us to acquire a more accurate relative chronology of landslide activity during the Holocene and Upper Pleistocene, and more importantly, to establish the pattern of landslides evolution in the Moldavian Plateau, North-Eastern Romania. The relict landslides are Lateglacial and Lower Holocene, the old landslides are post-Holocene Climatic Optimum and pre-Medieval, while the recent landslides are post-Medieval. The landslide magnitude decreased continuously, the new events being retrogressive reactivations of earlier events scarps and landslide bodies (as shown by the ERT data). Further studies on absolute dating will improve the relative chronology. Still, while not all the landslides can be dated, the methodology that we describe can be applied to increase the spatial density of the relative chronology. The presented approach can be used in other regions all over the world to establish the relative age of landslide inventories when archaeological topography can be related to landslide topography.

Geomorphometric Methods for Burial Mound Recognition and Extraction from High-Resolution LiDAR DEMs

“…For the southern study area, burial mounds 29 and 32 ( Figures 2 and 18 and Figure S14) failed to be identified. Burial mound 29 was located at the edge of the ridge, a part of it being affected by a landslide scarp, a situation that was already identified in the study area [63] as characteristic for certain burial mound locations. This position makes the corresponding segment geomorphometric characteristics different than the burial mound segments used for training, which are located on flat or gentle slope surface.…”

“…(a high-resolution version can be found at https://doi.org/10.6084/m9.figshare.11798613.v2) Figure 3. The stratigraphy of a burial mound (yellow to brown and grey) excavated by [61] at Corlăţeşti (Botoşani, County), redrawn after [61] with overlayed present-day LiDAR topography (red line); the location of this mound is represented in Figure 2 of [63], available in high-resolution at https://doi.org/10.1371/journal.pone.0227335.g002 or https://doi.org/10.6084/m9.figshare.11340419. (a high-resolution version can be found at https://doi.org/10.6084/m9.figshare.11798616.v1) Figure 3.…”

Geomorphometric Methods for Burial Mound Recognition and Extraction from High Resolution LiDAR DEMs

“…Sensors 2020, 20, x FOR PEER REVIEW 3 of 30 images from the spring or autumn season, when the agricultural fields are tilled, could be used to identify the burial mounds [38], the soil developed on these features having lighter colors than the A horizon of the surroundings soils (chernozems and faeozems). The stratigraphy of a burial mound (yellow to brown and grey) excavated by [61] at Corlăţeşti (Botoşani, County), redrawn after [61] with overlayed present-day LiDAR topography (red line); the location of this mound is represented in Figure 2 of [63], available in high-resolution at https://doi.org/10.1371/journal.pone.0227335.g002 or https://doi.org/10.6084/m9.figshare.11340419. (a high-resolution version can be found at https://doi.org/10.6084/m9.figshare.11798616.v1) The stratigraphy of a burial mound (yellow to brown and grey) excavated by [61] at Corlăţeşti (Botoşani, County), redrawn after [61] with overlayed present-day LiDAR topography (red line); the location of this mound is represented in Figure 2 of [63], available in high-resolution at https://doi.org/10.1371/journal.pone.0227335.g002 or https://doi.org/10.6084/m9.figshare.11340419.…”

The need for protecting, promoting, and managing a Quaternary geoheritage site: Bahluiet Valley at Costești village (Moldavian Plateau, North-Eastern Romania

“…1 -locations of other fortified sites from the Moldavian Plateau are shown). The archaeological topography was used to assess the relative chronology of landslides from the Moldavian Plateau during the Holocene (Niculiță et al 2016a(Niculiță et al , 2019. These locations are important heritage sites for Romanian prehistory, where landslides also developed after the population disappearance representing a significant risk factor for these archaeological sites (Niculiță and Mărgărint 2018).…”