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The impacts of relative sea‐level (RSL) variations and crust mobility on the development of ancient harbours in the northern Persian Gulf are poorly understood. Many unanswered questions remain with regard to the main reasons for a shift in the location of the most important ancient harbours in the northern part of the Persian Gulf coastal since 50 BC. Furthermore, some important early Islamic harbours, such as Siraf, have ancient city quarters that are today below the present sea level. The aim of this study is to evaluate the relationship between halokinesis and RSL changes using geophysical models and multidisciplinary geoarchaeological methods at the ancient Sassanid–Islamic site of Bataneh (presently known as Najirum) located at the foothill of an active Darang salt diapir. The results reveal that after the mid‐Holocene highstand, RSL regression was not continuous. The studied facies have recorded three RSL oscillations. The oscillations are correlated with the eustatic sea‐level position. During the first lowstand, important Sassanid harbours shifted from Rishar to Apologus. The second lowstand is consistent with the transition of maritime trade from Apologus to Siraf, during the Abbasid dynasty. Uplift of the Bataneh coastal zone exposed the city to risks from flooding and fluvial debris flows. With a modification of the local watershed, runoff water originating from the salt anticlinal was controlled and used for the extraction of gypsum in evaporation ponds. The economic expansion of Siraf led to Bataneh being abandoned with a shift in trade to Kish Island. [ABSTRACT FROM AUTHOR]

Abstract: The western part of the Liguria Region (NW Mediterranean Sea) has been reported as tectonically stable to slowly uplifting since the Late Pleistocene. Despite good knowledge of the coastal geomorphological features above sea level, very little information is available on the characteristics of the underwater coastlines. Direct and indirect underwater surveys carried out in the area between Vado Ligure and Finale Ligure (Western Liguria) allowed the identification of several surfaces of marine origin, in four sites, at three depth intervals: 8–13m, 17–23m and 27–30m. These values appear to be in bathymetric analogy with those reported by other authors along the Italian coastlines, in areas where the tectonic movements along the Late Quaternary are considered negligible on the basis of the elevation of the MIS 5.5 shoreline. Although few chronological constraints are possible due to the lack of dateable material, the marine morphologies identified in this study constrain their ages to the Middle and Late Quaternary. [Copyright &y& Elsevier]

Tidal flats play an important role in promoting coastal biodiversity, defense against flooding, land reclamation and recreation. Many coastal tidal flats, especially the tide-dominant ones, are muddy. However, the number of studies on the profile shape and surficial sediment distribution of muddy tidal flats is small compared to sandy beaches. Based on high spatial-resolution measurements along the tide-dominant Jiangsu Coast, China, we analyzed the morphology and sediment characteristics of the unvegetated intertidal flats along the Jiangsu Coast. The Jiangsu Coast can be divided into an eroding northern part (north coast) and an accreting southern part (south coast). The beach slope of the north coast shows a southward flattening trend, apart from some outliers related to rocky parts of the coastline. We found alternating very fine and coarse sediment (depending on the local clay content) for different locations along the north coast, which can be explained from consolidation and armoring-induced erosion resistance. In the south coast, we found gradual coarsening of bed surface sediment and gradual flattening of beach slopes to the south. This seemingly unexpected pattern is explained by the flood-dominant current causing landward sediment transport, larger tidal range in the south part, sheltering effect of the Radial Sand Ridges, and contribution of different sediment sources, viz. the Abandoned Yellow River Delta and the Radial Sand Ridges. In the cross-shore direction, the sediment grain size decreases landward. Waves are only of secondary importance for the sediment dynamics at the unvegetated tidal flats along the Jiangsu Coast. [ABSTRACT FROM AUTHOR]

We constrain the GIA signal and its uncertainty for southeastern Canada and northeastern USA using 1013 relative sea-level (RSL) data points distributed over 38 sites from two regional RSL data compilations containing 544 sea-level index points, 232 marine limiting data points, and 237 terrestrial limiting data points. This state-of-the-art dataset was compared to output from 14,960 model runs based on a 1D (spherically-symmetric) Earth model and 34 different North American ice sheet reconstructions. By considering different data subsets (regional partitioning), we found that significantly improved fits can be obtained by separating the data into two larger subregions: the first one close to the central section of the Laurentide Ice Sheet (including Hudson Bay, Ungava Peninsula, and Labrador), and the second one along the Atlantic coast of Canada and the USA (encompassing Newfoundland, St. Lawrence Corridor, New Brunswick and Nova Scotia, and Maine and Massachusetts). For the first subregion, relatively low lower mantle viscosity (1–2 × 1021 Pas; from the considered range of 1–90 × 1021 Pas) and relatively high upper mantle viscosity (greater than 0.5 × 1021 Pas from the considered range of 0.05–5 × 1021 Pas) for a given ice loading history can provide good quality fits. On the other hand, quality fits for the second subregion require intermediate values for these parameters (specifically, upper mantle viscosity of 0.5–1 × 1021 Pas and lower mantle viscosity of 20–30 × 1021 Pas). When considering model uncertainty bounds, ∼91.6% of the observations (928 out of 1013 RSL data points) can be captured, while the remaining residuals (∼8.4%) reflect some observational errors (outliers) and systematic error in the model. Given the 1D analysis suggests the existence of significant lateral Earth structure, we explored this aspect via the use of a 3D finite volume Earth model. Considering two realizations of lateral Earth structure based on two shear-wave tomographic models, the 3D results support the spatial partitioning of the whole study region into two larger subregions. However, the 3D model was unable to improve upon the data-model fits obtained with the 1D model, indicating limitations in the models of lateral structure and/or the adopted ice models, which are reconstructed based on 1D Earth models. Finally, our 1D Earth modelling results indicate that, within the first subregion, ice history models with relatively thick ice during the early phase of deglaciation (prior to ∼13 ka) and thinner ice in the early Holocene are preferred by the RSL data. • We constrain a set of optimal Earth-ice models for eastern Canada and northeastern US through 1D (radially varying viscosity structure) GIA modelling. We utilize a larger model parameter set for the Earth's viscosity structure and the deglaciation history compared to previous studies, and so more accurately quantify the parametric uncertainty bounds. • We employ quality-assessed RSL databases and consider both sea-level index points and limiting data points to quantify data-model misfits (most previous studies only used sea-level index points for this purpose). • We also evaluate the effect of lateral viscosity perturbations in our study area on the GIA-derived sea-level changes to determine whether there is evidence for a large impact of lateral Earth structure and whether a small set of 3D models can better fit the RSL data. • The optimal GIA signal (with its uncertainty bounds) estimated from our study can be used for different applications. For example, the GIA signal can be removed from geodetic measurements (e.g., GRACE satellite gravimetry, GNSS) to better constrain and understand non-GIA processes (e.g., hydrology) contributing to the contemporary mass changes and vertical land motion. Our model results can also be used to produce improved projections of mean sea-level change and nuisance flooding in the coming decades. Model output (optimal and uncertainty bounds) will be made available for end users to quantify the influence of GIA on vertical land motion and (past and future) RSL in this region. • Our uncertainty analysis considers a third approach that explicitly incorporates estimates of model structural uncertainty in defining a set of model parameters that are compatible with the adopted observational constraints. Our application of this approach, known as history matching, is one of the first in paleo sea level and GIA modelling studies and, as such, we hope it can be used as an example which future studies can build upon. [ABSTRACT FROM AUTHOR]

Abstract Successful heritage management requires a robust comprehension of the threats facing archaeological sites, at both current and future timescales. Siraf, on the Persian Gulf of Iran, is a site of national and international importance whose history stretches back to the Sassanid period (224–652 AD). In the present context of global change (drought and relative sea-level rise) and anthropogenic impacts (coastal artificialization and reduced sediment supply), the city's waterfront archaeology is undergoing significant erosion. Nonetheless, at present, the processes leading to the loss of Siraf's in situ archaeological remains are still poorly understood, including the rates, timing and drivers of coastal erosion. Here we use Landsat images to monitor shoreline changes along the Siraf coastline between 1973 and 2016. We spatially quantify the causes and impacts of surface changes along 244 transects. The results demonstrate that coastal erosion is responsible for widespread and archaeologically significant damage, with 48% of the studied transects showing erosion during the period 1973–2016. We elucidate significant temporal variations in the data and, most notably, demonstrate that continued drought since the early 2000s has impacted upon sediment supply to coastal areas, severely accentuating erosion. For instance, between 2003 and 2016, 70% of transects recorded shoreline retreat with worrying implications for the waterfront archaeology of Siraf. These quantitative results provide invaluable spatial information regarding the causes and impacts of erosion upon Siraf's waterfront heritage, in addition to furnishing a template for the protection of the city's internationally important cultural heritage. Highlights • Successful heritage management requires understanding of the threats facing archaeological sites. • We spatially quantify shoreline changes along the Siraf coastline between 1973 and 2016. • 48% of the studied transects show erosion during the period 1973–2016, leading to widespread archaeological damage. • We provide a template for the protection of Siraf's internationally important cultural héritage. [ABSTRACT FROM AUTHOR]

We present a historical record of landfalling tropical cyclones (TCs, 85 events) over the Mascarene Islands (southern Indian Ocean) since the 17th century to evaluate interannual-to-decadal-scale changes in past TC variability, from the cooler Little Ice Age (LIA) to the present warming world, and to contextualize present and future changes in risk estimates. For the Mascarene Islands, we observe a mean fourfold increase in regional landfalling TCs, beginning around 1940. Before this date, the historical TC data exhibit clear decadal cycles, which mirror solar radiative forcing. This historical record demonstrates how enhanced understanding of past variability can improve baseline risk estimates of TCs making landfall in the SW Indian Ocean basin. • We report a ∼ 300 years historical time series of tropical cyclones from the Mascarene Islands (SW Indian Ocean). • Human activity has probably caused a mean fourfold increase in regional landfalling TCs, beginning ∼1940. • Before 1940, historical TC data mirror solar radiative forcing. [ABSTRACT FROM AUTHOR]

The mid-Tyrrhenian coast is the most complex volcano-tectonic sector in the Mediterranean basin. Here the vertical ground movements (VGMs) due to the interaction between extensive tectonic processes and volcano-tectonic activities have a significant impact on both past and future sea-level evolution. This area represents the youngest basin of the western Mediterranean and it hosts one of the most active volcanic districts, formed by the Campi Flegrei and Vesuvius volcanoes, which are worldwide known for the vertical ground movements accompanying their volcanic activity since the Late Pleistocene. The short-lived alternation of subsidence and uplift has induced great changes in inland areas and abrupt coastal landscape transformations since that time. This study aimed to spatially constrain the magnitude of the vertical displacements which significantly affected this coastal sector during the last millennia. We then reconstructed the multiple relative sea-level oscillations that occurred during the Late-Quaternary by developing a comprehensive WebGIS of sea-level index and limiting points (https://dist.altervista.org/seaproxy/). This includes newly produced sea-level data from recent marine surveys, which were coupled to previously available data standardized according to the recent international guidelines for RSL studies. This allowed producing a multiproxy dataset composed of depositional, erosional, biological, and archaeological sea-level markers, in this very complex Mediterranean area. The collected sea-level data were further compared with a number of geophysical predictions in order to disentangle the different components which influenced the sea-level evolution. Moreover, the tectonic rates derived from the available MIS 5e sea-level data were used to shift the LIG elevations vertically and backwards in time in order to constrain the Last Interglacial RSLs to certain levels depending on the areas. Finally, we used GIS techniques to spatially constrain the coastal sectors more vulnerable to the coupled effects of future sea-level rise and VGMs in the next decades. • Reconstruction of Late Quaternary sea-level oscillations in the mid-Thyrrenian area. • Development of a WebGIS of sea-level data in the mid-Thyrrenian area. • Definition of Vertical ground movements due to volcano-tectonic activities. • Holocene vertical displacements by comparing sea-level data and GIA models. • Long-term tectonic rates from MIS 5e sea-level data. [ABSTRACT FROM AUTHOR]

In the context of industrial-era global change, Mediterranean coastal areas are threatened by relative sea level (RSL) rise. Shifts in the drivers of coastal dynamics are forecasted to trigger changes in the frequency of flooding of low-lying areas, with significant effects on marine-coastal environments, societies, economy and urban systems. Here, we probe coastal floods in the eastern part of the Gulf of Venice (coastal Croatia) to understand the drivers of saltwater intrusions. We reconstructed RSL rise in the north-eastern Adriatic during the Holocene based on 43 RSL index points and analyzed the evolution of coastal submersions on the Istrian Peninsula for the last 5200 years based on inputs of marine components and increases in supratidal scrubs. We produced pollen-based climate reconstructions to analyze the potential effects of air temperature and precipitation changes on submersions. We investigated the response of precipitation and temperature to mid-late Holocene summer/winter insolation forcing and insolation-induced changes in sea surface temperatures (SSTs). We found that during periods of warmer SST, coastal flooding increased markedly. This process seems to have been initiated by warmer atmospheric temperatures that led to increases in summer evaporation, counterbalancing the effects of heavy precipitation during winter. As a result, freshwater flows into coastal areas were reduced and resulted in recurrent inputs of saltwater inland. Our study suggests that present-day climate drivers (increases in SSTs and air temperatures, and decreases in precipitation) will probably favour frequent coastal flooding, a process that will be amplified by RSL rise. • Reconstruction of 5200 years of coastal flooding in the north-eastern Adriatic. • Analysis of relative sea-level rise and climate dynamics as drivers of floods. • Reconstruction of environmental impacts resulting from recurrent coastal flooding. • Past data suggest that present climate drivers will favour frequent coastal flooding. [ABSTRACT FROM AUTHOR]