The coastal landslides of Shetland

Little is known of hard-rock coastal landsliding in Scotland. We identify 128 individual coastal landslides or landslide complexes >50 m wide along the coasts of Shetland. Most are apparently translational slides characterized by headscarps, displaced blocks and/or debris runout, but 13 deep-seated failures with tension cracks up to 200 m inland from cliff crests were also identified. Thirty-one sites exhibit evidence of at least localized recent activity. Landslide distribution is primarily determined by the distribution of coastal cliffs >30 m high, and they are preferentially developed on metasedimentary rocks. Analysis of 16 landslides on Fetlar (NE Shetland) indicates that most are translational dip-slip failures; 3 represent deep-seated failures and several exhibit active frontal erosion attributable to basal sapping by storm waves. As these landslides terminate in shallow water, failure was probably initiated when rising sea level resulted in footslope erosion and upslope propagation of instability, causing downslope displacement of landslide blocks on upper slopes. ¹⁰Be exposure dating of two headscarps yielded ages of 4.8?±?0.2 ka and 4.4?±?0.2 ka, consistent with the onset of footslope erosion as sea level rose. Our results suggest that landslides have played a hitherto undocumented but important role in retreat of cliffed coastlines in Scotland.     

Field Measurements of Wave Characteristics on a Near‐Horizontal Shore Platform,Mahia Peninsula,North Island,New Zealand

Waves are an important process responsible for the initiation and subsequent development of intertidal shore platforms. However, few field studies to date have described wave processes on shore platforms. A field experiment was conducted using an across‐shore array of wave gauges, including a directional sensor, on a near‐horizontal platform at Mahia Peninsula, North Island, New Zealand. Results show that the platform is very efficient in filtering wave energy at gravity wave frequencies (>0.05 Hz), with 40–80% reduction in wave height measured across the 140 m wide platform. By contrast, infragravity waves are present on the platform and increase in magnitude towards the cliff toe. Directional wave analysis indicates that wave reflection is mainly restricted to infragravity wave frequencies, demonstrating the differences in gravity and infragravity wave behaviour on the platform studied. Results indicate that, under fair weather conditions, the role of waves as an agent of cliff toe erosion is likely to be limited at present, although they are probably important for removing sediments accumulated at the cliff toe. The observed increase in infragravity wave energy towards the cliff toe implies that these long‐period waves may be important geomorphic agents on shore platforms.     

南京栖霞山千佛岩石窟的测绘与编号

本文是南京栖霞山千佛岩石窟科学考察成果的第一部分。作者对千佛岩石窟进行了精确的地形测量,结合洞窟形制与窟檐的测绘、佛像的调查对洞窟进行了分区与编号,并对石窟造像的现状进行了综述。     

Refining Broad-Scale Vulnerability Assessment of Coastal Archaeological Resources,Lough Foyle,Northern Ireland

Increasing evidence indicates that ongoing and future climate change impacts, such as enhanced coastal erosion driven by intensified storms and sea-level rise, will be destructive or problematic for coastal archaeological heritage. Approaches to this problem range from broad-scale GIS-based vulnerability assessments to site-scale monitoring and survey. In all cases, the approach chosen should be based on the best-available data on the local historic environment and pattern of coastal change. Therefore, this paper will demonstrate how such data can be successively acquired and enhanced using an integrated approach that builds on and refines a previously conducted broad-scale vulnerability assessment. This approach was adopted in the study region (Northern Ireland) owing to a lack of coherent and up-to-date information on shoreline change. This approach incorporated the GIS-based Digital Shoreline Analysis System (DSAS) to quantify and analyze local shoreline change. DSAS is a software extension for ESRI ArcGIS which allows calculation of rate-of-change statistics using past shorelines identified from georeferenced historic maps and vertical aerial imagery. Additionally, a field survey was conducted to assess the condition of recorded sites, and identify unrecorded ones. Results revealed a more complex pattern of shoreline change in the study area (Magilligan Foreland, Lough Foyle) than previously anticipated, with zones of significant erosion interspersed with areas of stability or advance. Fifty-one new sites ranging from the prehistoric period to the Second World War were also identified. The new information was used to develop a priority classification based on site significance, condition and risk level which improved significantly on the uniform classification of the original broad-scale assessment.     

Cartographic,Geophysical and Diver Surveys of the Medieval Town Site at Dunwich,Suffolk, England

This paper presents the results of an integrated historical and geophysical survey of a medieval town lost through cliff recession and coastal inundation. Key objectives included evaluating historic maps in supporting the relocation and identification of major buildings, and applying integrated multibeam, side‐scan and sub‐bottom profiling to determine the location and extent of archaeological remains. The results demonstrate that cartographic sources from 1587 onwards can be a reliable source of data to guide geophysical survey. Integration of historical mapping with geophysical data enabled identification of the remains of two medieval structures, and the tentative identification of two others. © 2010 The Authors     

Chronology and Cultural Activity in Johnson Canyon Cliff Dwellings: Interpretations from Tree-Ring Data

Abstract

Archaeological tree-ring samples were collected during the summer of 1974 from nine cliff dwellings in the tributaries of Johnson Canyon on the Ute Mountain Indian Reservation in SW Colorado. The cliff dwellings belong to the Mesa Verde branch of the Anasazi cultural tradition and on the basis of ceramics and architecture could be assigned to the McElmo phase (1050-1150 A.C.) and the Mesa Verde phase (1150-1300 A.C.). Of a total of 461 tree-ring samples, 352 could be dated. These dates and other observations made during the analysis are applied toward refinement of the dating of the sites as well as to interpretations about utilization of timber resources, environment, and demography. Two clusters of cutting dates consistently occur in most of the sites indicating two periods of construction activity, one in the middle 1100s and the other in the early 1200s. The existing architecture at these sites dates to the early 1200s while the earlier structures have apparently been dismantled and their materials reused. These data suggest an occupation of the area beginning in the 1140s, followed by an abandonment by the 1160s. The area was reoccupied in the early 1200s for only 30 to 40 years before final abandonment.     

A Fading Memory: The North Yorkshire Coastal Alum Industry in the Light of Recent Analytical Field Survey by English Heritage

Abstract

For over 250 years from 1604, the North York Moors were the centre of the English alum industry. The principal use of alum was as a mordant to fix and enhance the colour of dyed cloth. It was made by quarrying, burning and steeping vast quantities of shale to produce an impure solution of aluminium sulphate; then, at alum houses, the liquor was concentrated by boiling, and an alkali added to form alum. The North Yorkshire quarries exploited both inland and coastal shale exposures, but the most successful quarry/alum house complexes (alum works) were situated on or near the coast. Even when operational, the latter had to contend with periodic infrastructure losses from landslips and cliff falls; with closure, they now form a diminishing archaeological resource steadily sliding into the sea. This paper reviews the present understanding of the industrial process in the light of recent analytical field survey by English Heritage of four hitherto poorly recorded works, three of which are coastal. In so doing, it highlights the disproportionate loss of certain classes of features at the coastal sites, and advocates the need to do more to compare the latter to their inland counterparts, to place the industry in its wider British and European context, and to examine it from an economic as well as a technological perspective.     

THE DISCOVERY OF AN ANGLO‐SAXON GRUBENHAUS AT NEW BEWICK,NORTHERN UK USING ELECTRICAL SURVEYING AND PREDICTIVE DECONVOLUTION

Twin‐probe and 33‐fold multiplexed Wenner electrical resistivity surveys were carried out at New Bewick, northern UK to examine the extent of crop marks and potential Grubenhäuser (sunken‐featured buildings, sunken‐floored buildings or SFBs). The twin‐probe method was faster, but provided data with a lower spatial resolution. However, the Wenner array data was affected by characteristic ‘M’‐ or ‘W’‐shaped responses over filled excavations such as those expected to represent a Grubenhaus. The raw Wenner array data have been analysed using one‐dimensional and two‐dimensional predictive deconvolution in order to remove these artefacts. The deconvolution was carried out using an inverse matrix element method. The filtered results indicate the presence of anomalies consistent with the presence of at least six Grubenhäuser and other anomalies concurrent with the linear crop‐marks. One particular anomaly measured about 5 m by 4 m and with a pit depth of 0.6 m below 0.3 m of topsoil. This anomaly was subsequently excavated and a Grubenhaus was discovered at the site. The excavated Grubenhaus measured 4.7 m by 3.9 m with a pit depth of 0.5 m below the base of the topsoil, confirming the electrical survey results.     

Geophysical investigations in the service of Mount Carmel (Israel) prehistoric research

Geophysical investigations in el-Wad Cave, Mount Carmel, Israel, enabled the mapping of the surface of the bedrock and a reconstruction of the depth of the archeological deposits. Seismic refraction and Ground Penetrating Radar (GPR) provided similar results, indicating the potential value of geophysical studies when one seeks to reconstruct site features and establish future excavation strategies. Results of a GPR survey later conducted in the adjacent Jamal Cave were supported, to a high degree, by subsequent archeological excavations in the course of which Lower and Middle Paleolithic layers were unearthed.A Continuous Vertical Electrical Sounding (CVES) geoelectric survey in the (collapsed) Misliya Cave indicates a low resistivity layer at the upper, central part of the cave, suggesting that lithified archeological deposits, of ca. 4 m, are preserved at the site. This has been supported by a test excavation recently conducted at the site.More intriguing is the case of what, on the basis of the outer morphology of the cliff, seemed to be another collapsed cave just to the north of el-Wad. The CVES survey, at the bottom of the cliff and across the hypothesized cave (or chamber), shows a two-layer model, with a low resistivity (100–200 ohm-m) layer, overlying a layer of high resistivity (8000–10,000 ohm-m). A trial trench indicates that here the bedrock is covered by shallow, recent, surface material, with no archeological value.All three methods of geophysical investigation proved applicable and resulted in the successful evaluation of sites' location, depth and spatial extension, thus forming essential tools in future prehistoric research.     

Quantifying the effects of erosion on the archaeology of intertidal environments: A new approach and its implications for their management

Abstract

While the high archaeological and palaeoecological value of intertidal deposits has become well known, approaches to their management remain extremely restricted. Despite the often high levels of erosion experienced by some sites there has been very little development in methods aimed at understanding or quantifying the threats. This paper presents an approach aimed at monitoring erosion within the Humber estuary, UK, where previous finds including Bronze Age boat remains and trackways have made it an area of international importance. Two sites have been investigated and the results from these demonstrate both the high rate of sediment removal and also the highly variable nature of intertidal erosion. It is argued that global figures relating to rates of erosion are wholly inappropriate when attempting to manage archaeological deposits that have survived in intertidal environments. Rather, management of such archaeologically rich but threatened landscapes is only possible through regular quantitative monitoring. Such an approach offers coastal protection authorities a valuable opportunity to assess the long-term progress of erosion and coastal change. This methodology could be employed alongside management agreements within those particular coastal cells or process units that have been identified in a Shoreline Management Plan.     

First excavation of intact Middle Stone Age layers at Ysterfontein,Western Cape Province,South Africa: implications for Middle Stone Age ecology

Excavations into a coastal cliff at Ysterfontein (YFT) 1, South Africa, have revealed 2.5–3 m of stratified sands containing classic Middle Stone Age (MSA) stone artifacts, abundant mussel and limpet shells, numerous fragments of ostrich eggshell, and somewhat rarer bones from mammals, birds, tortoises, and snakes. The sands apparently filled a crevice-like, calcrete shelter, where the artifacts and animal remains accumulated partly in place and perhaps partly through slippage down the face of a dune that once stood between the site and the sea. Accelerator radiocarbon dating of ostrich eggshell places the sequence before 33,400 years ago. Artifact typology provisionally suggests that it formed after 70,000 years ago. The fauna resembles faunas from the handful of other known coastal MSA sites and contrasts with faunas from regional Later Stone Age (LSA) sites in its low diversity of coastal marine species and in the large size of its limpets and tortoises. The difference suggests that MSA people exploited local resources less intensively, probably because their populations were less dense.     

Use of ground penetrating radar to map subsurface archaeological features in an urban area

The ground penetrating radar (GPR) technique was used to investigate the subsurface in an urban area located in Mesagne (Italy) to obtain a map of the archaeological features in the ground. The GPR survey was undertaken at selected locations placed near (about 50 m) to a necropolis dating from the Messapian to the Roman imperial age, using a GSSI Sir System 2 incorporating 200 and 500 MHz centre frequency antennae. The selected areas (A and B) were surveyed along parallel 1 m spaced profiles using a 200 MHz antenna in area A and along parallel 0.5 m spaced profiles using a 500 MHz antenna in area B. For the selected areas the processed data were visualised in 3D space not only by means of the standard time slice technique, but also by means of a recently proposed approach, namely by iso-amplitude surfaces of the complex trace amplitude. The immediacy in revealing the spatial positioning of highly reflecting bodies, such as the anomaly interpreted as an old hypogeum room in area A, makes 3D visualisation techniques very attractive in archaeological applications of GPR. Their sensitivity to the signal/noise ratio is, on the other hand, highlighted by the quite poor performance in area B, where the only reliable result provided by all the techniques was the ancient living surface reflection, whereas none of them could effectively enhance the visibility of weak hyperbola reflections noted on 2D sections and probably related to the walls located on the ancient living surface. The performance of the various techniques in these two different situations allowed insights into their main advantages and drawbacks to be gained.     

Protecting a ‘Homeric landscape’: The making of the Butrint National Park,Albania

Abstract

This paper will present research on the vulnerability mapping of coastal archaeological sites currently being undertaken in Northern Ireland. The ultimate aim of this research is improve current predictions of where archaeological sites and landscapes will be at risk in the future from coastal erosion. The initial stage of this approach uses a suite of oblique aerial photographs to construct a baseline of eroding locations and coastal geomorphology. The erosion baseline can then be integrated with existing historic environment records to obtain a coarse first-pass archaeological vulnerability assessment. Subsequent stages can then use this assessment to prioritize future mitigation such as field surveys or monitoring exercises, or conduct further refinements of vulnerability classifications by incorporating information on site type and positioning on a local scale.     

Shoreline Change and Coastal Vulnerability Characterization with Landsat Imagery: A Case Study in the Outer Hebrides,Scotland

Abstract

Observation of cause–effect patterns of change in coastal environments provides insights into vulnerable areas and supports prediction and adaptation to flooding and erosion. Historic and periodic (6–8 year intervals) imagery from the Landsat archive is used to investigate transformations in the Atlantic coast of two Scottish islands over the period 1989–2011. Supervised classification of spectrally normalized images followed by change detection and spatial analysis reveals the patterns of change and the location of the most dynamic coastal areas. Quantitative measures of recent shifts and movement rates of relevant coastal lines, such as the lower limit of land-based vegetation, are assessed with the Digital Shoreline Analysis System. While very low rates are indicated for horizontal changes in the position of the lower limit of land-based vegetation (0.3?m?y^?1), specific areas have been subjected to high rates of coastal progradation as well as erosion (e.g. 2.5?m?y^?1 at Stilligarry). Information derived from satellite data supports the characterization of geomorphologically dynamic coasts at regional scales. With a rich and open access archive of imagery, a commitment to continuity, and compatibility with the Earth observation missions of other space programs, the Landsat mission offers useful and otherwise unavailable data for monitoring of coastal areas.     

鲁北沿海地区先秦盐业遗址2007年调查简报

2007年,北京大学中国考古学研究中心与山东省文物考古研究所等单位联合组成的鲁北沿海地区先秦盐业考古课题组,对鲁北沿海地区的莱州湾沿岸地区和黄河三角洲地区的遗址(群)进行了考古调查,新发现和确定了广饶东北坞、南河崖,寿光双王城、大荒北央、寒亭央子以及沾化杨家等大型先秦盐业遗址群,并首次确认了东周时期的制盐工具和遗址群。通过此次调查,进一步了解了鲁北沿海地区先秦盐业遗存的分布情况、规模及保存状况,明确了鲁北沿海地区是殷墟时期商王朝的制盐中心这一认识。     

Resistivity Tomography Imaging of the Substratum of the Bedestan Monumental Complex at Nicosia,Cyprus

In the framework of the EU–UNDP project ‘Rehabilitation of Old Nicosia’ (Cyprus, 2004–9), a high‐resolution geoelectrical survey has been performed inside the partially ruined monumental complex of St Nicholas of the English, now called the Bedestan, which was designed to become a venue space for cultural activities. The aim was to detect buried traces of a Byzantine basilica of the sixth century, on the ruins of which, according to tradition, the construction of St Nicholas was begun in the 12th century. The survey has been conducted on the floor of the monument, using a dipole–dipole electrode array along two perpendicular sets of profiles. In order to model the resistivity distribution, the probability‐based electrical resistivity tomography inversion (PERTI) method has been applied. Sets of aligned blocks with resistivity in the range 100–400 ohm·m, bounding a three‐room rectangular space, and traces of a rounded structure with mean resistivity about 150 ohm·m, appearing at one extremity of the central room, are the main resistive features recognized down to 4 m depth, within a conductive background with resistivity in the range 20–40 ohm·m. Altogether, these resistive features, showing in plan the shape of a church characterized by a central nave with an apse and two side aisles, have been interpreted as an evidence of the existence of remains of the earlier Byzantine basilica. Moreover, small volumes with resistivity in the range 10–12.6 ohm·m have been found, scattered underneath the whole surveyed area. Taking into account the PERTI results, ground‐truth has been performed in two sites, designed to become two permanent protected exposures of the archaeological findings beneath the floor of the newly restored Bedestan. At one site, excavations detected remains of masonry in correspondence of the alignment of resistive blocks at the left margin of the left side aisle of the churchlike structure. At the other site, graves, entirely filled with wet debris in an alluvial soil matrix, have, instead, been found in correspondence with the greatest conductive volume, detected outside the perimeter of the churchlike structure. Both findings have been dated back to the sixth century. Since the Bedestan case‐history is one of the first applications of the PERTI algorithm to real field data sets, its performance has been tested using the well‐known ERTLab^TM commercial software as benchmark. The comparison has shown a general consistency between the two inversions, and also confirmed the much higher computing speed, better filtering capacity and greater versatility of the PERTI algorithm, already outlined in a previous paper where only synthetic models were tested.     

Tell formation processes as indicated from geoarchaeological and geochemical investigations at Xeropolis,Euboea, Greece

Xeropolis is a tell site on the island of Euboea, Greece just to the east of the village of Lefkandi, and was occupied from the Early Bronze Age to the Early Iron Age. Excavations in recent years have provided an opportunity to investigate site formation processes using geoarchaeological and geochemical techniques. Sediments derived from the tell on the southern side have been lost by coastal erosion whilst those on the north mantle the flanking slope. Of particular interest is a homogeneous and unstratified deposit of over 2 m which overlies the archaeology near the southern perimeter of the summit area. The soil structure as evident in thin sections indicates a high degree of bioturbation, probably stimulated by recent manuring and cultivation. The implication is that tillage erosion has had a major impact on the morphology as well as on the surface soils of the tell. Despite such reworking and redeposition of near surface materials, it is still possible from multi-element analysis to identify the geochemical distinctiveness of six archaeological contexts (pit, house, plaster floor, alley, road and yard); pits and floors have high loadings of all elements except Pb; in contrast pits and floors have the lowest elemental concentrations.     

炳灵寺石窟早期调查中的重要遗迹——以冯国瑞《炳灵寺石窟勘察记》为中心

炳灵寺石窟学术意义上的发现始于1951年冯国瑞的初步考察,次年又组织勘察团进行了第一次正式勘察。通过对照现存窟龛与早期考察成果(包括报告、老照片等),可以重新确认冯国瑞首次调查炳灵寺石窟的路线,即在崖面底部从南向北行至大佛南侧后,再到对岸以望远镜观察崖壁中部无法到达的窟龛。《炳灵寺石窟勘察记》也按照他考察路线的顺序依次记录了所观察到的窟龛遗迹,其中许多现已不存。例如,"武德二年"题记当时很可能在靠近大佛南侧的洞窟中;"永康四年"题记也并非冯国瑞错认,其位置可能不在第169窟中。1952年,考察团再次来到炳灵寺,攀登了除第169窟和第172窟外的所有洞窟,补充了测绘图、照片等宝贵资料。70年前冯国瑞参与的这两次考察将学术界的目光投向炳灵寺石窟,如今更需要对当时的考察记录进行充分讨论与解读。     

The use of magnetometry and pole-dipole resistivity for locating Nabataean Hawar archeological site in the SW-Jordan

This paper is focused on the joint use of magnetometry and pole-dipole electrical resistivity geophysical methods for assessing their capability in the detection of a prehistoric site in the southwestern Jordan. The survey area, Auara, was built in the first century BC during the Nabataean time and is located in a very arid environment framed on the east and north by white sandstone hills. In order to test this site, a number of magnetic stations and two pole-dipole resistivity traverses were carried out in the investigated area. Magnetic data were taken with one sensor at height of 0.8 m along survey lines spaced 1 m apart. Resistivity measurements were carried out utilizing the pole-dipole array along two profiles. A total of 32 geoelectrical stations spaced 2 m were made along the two profiles. Magnetic method found structure with contrasting physical properties to those of the surrounding material. The archeological interpretation of such structure is in terms of rectangular cistern (pool) with dimensions 26 × 16 m. A probable location of two buried walls spaced 16 m are indicated by low resistivity values.     

Barriers and Foot Combats

In 1985 a watching brief during gravel extraction at Hemington Fields, Castle Donington, Leicestershire, revealed a substantial timber and stone structure buried beneath 2–2.5 m of alluvium. Salvage excavation and a further watching brief have enabled the structure to be identified as a twelfth century mill dam associated with a possible low breast mill. This is the only mill site o f this date examined on a major river and has provided important information on medieval water management. Such sites indicate the great potential for archaeology within the flood plain of major rivers and contributes to a survey of palaeochannels in this area of the Trent valley.