Hydrological monitoring of an alluviated landscape in the lower Great Ouse valley at Over,Cambridgeshire: the quarry restoration phase

Abstract

This paper sets out the results of the last phase of the hydrological monitoring programme conducted at the Hanson Over quarry in Cambridgeshire, during the first full year (March 2004 to March 2005) in which the area of the first phase of gravel extraction was reinstated as reed beds under the management of the Royal Society for the Protection of Birds. It follows on from the studies of the pre-extraction and extraction phases, both published previously in Environmental Archaeology (French et al. 1999; French 2004). It is reassuring to report that the groundwater table in the formerly quarried area and the landscape immediately upstream and downstream has ostensibly been restored to pre-extraction levels, along with a return to previous pH, conductivity, redox and dissolved oxygen values in the groundwater system. Significantly, the continuing gradual fall in groundwater levels observed beyond 500 m from the quarry face for a distance of at least 1·5 km was seen to be arrested, although these had not quite recovered to pre-extraction levels downstream to the northeast. In addition, the soil moisture within the alluvial overburden and the buried palaeosol has also almost returned to pre-extraction levels. This indicates that the clay bunding of the formerly quarried areas acts as an effective barrier against further water abstraction, both inside and outside the sealed area, and allows the natural aquifer to begin to return to its previous levels of influence.

The study dramatically indicates that both the mineral operator, drainage authority and archaeological curator need to collaborate from the outset of any quarrying operation to ensure the continuing maintenance of the groundwater and soil moisture system regardless of how well the combined gravel and water abstraction processes are conducted, and how successful the post-quarry conservation is. As every site's landscape dynamics contribute to its individual hydrological setting, each case is different and requires tailored monitoring programmes to protect the archaeological and palaeo-environmental record from the adverse effects of water abstraction associated with development schemes.     

NEOLITHIC SOILS, MIDDENS AND ALLUVIUM IN THE LOWER WELLAND VALLEY

Summary. The soil micromorphological analysis of buried soils and probable 'midden' deposits buried beneath alluvium from six sites in the lower Welland valley between Maxey and Etton (Cambridgeshire) has revealed a deforested early Neolithic landscape which quickly became subject to seasonal alluviation. This paper suggests that the Neolithic/Bronze Age use of this landscape is directly related to its interpretation as an alluviated floodplain rather than an alluviated, former dry-land landscape.     

Landscape Archaeology in a Dry-Stream Valley near Tell es-Sâfì/Gath (Israel): Agricultural Terraces and the Origin of Fill Deposits

Abstract

As part of the long-term archaeological project being conducted at Tell e-Sâfi/Gath in the semi-arid foothills of the Judean Mountains, a first order dry stream channel located in a valley east of the main site was surveyed and soil pits excavated in selected locations. A ditch, 10 m in length, was dug perpendicular to one of the agricultural terraces, showing that the small valley is filled with soil to a depth of more than 3 m above bedrock. The fill dates mainly to the Byzantine period (ca. 4^th-7^th cent. CE), according to the ceramic sherds. Three check-dam walls and related terraces were found across the width of the valley. Surprisingly, the base of the check-dam does not go deeper than 50 em into the uppermost part of the fill, well above bedrock or gravel layers, while covering only the upper part of the terrace step. Thus we use the term “floating terrace wall” or “floating check-dams”. Each of the terrace walls is about 0.5 m high and 50 m long. The valley is bound by two slopes: (1) a northeast facing slope characterized by Nari outcrops (a hard calcrete crust in the upper part of the chalk bedrock) and soil pockets, and (2) a southwest facing slope without Nari. The source of most valley fill material is apparently from the slope without Nari. The valley shows comparatively little accumulation during the Iron Age and very much accumulation during the Byzantine period. The main cause seems to be human-made earth movement and terrace building during the Byzantine period, rather than passive erosion and accumulation as a result of general environmental pressure by human activity.     

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.     

Holocene sulphur-rich palaeochannel sediments: diagenetic conditions,magnetic properties and archaeological implications

Extensive aggregate extraction in the middle Trent valley, England, has revealed a sequence of Holocene palaeochannels associated with nationally important, and predominantly organic, archaeological remains. This paper reports observations of hyper-acidity (below pH 2), high natural magnetism and metallic sphaerules (framboids) in Holocene palaeochannel sediments at two sites in the middle Trent valley. These properties are associated with high natural remanent magnetism which has allowed the successful palaeomagnetic dating of palaeochannel fills at one of these sites (Hemington). These sediment properties are the result of the formation of ferromagnetic iron sulphides, including griegite, under conditions of high sulphur availability (from groundwater) in the presence of metallic ions and organic matter under low redox conditions, with later oxidation producing the extreme natural acidity through oxidation of disulphide (pyrite). These findings explain why, under certain groundwater conditions, alluvial palaeochannel sediments can carry post-depositional remanent magnetisation and be suitable for palaeomagnetic dating. The low pH may also be beneficial in the initial stage of wood preservation and if the sediments remain waterlogged, but probably not retard decomposition after drainage and acidification, a process that is increasingly being recognised as a threat to archaeological sites in wetland environments.     

Temporal Patterns in Ceramic Production in the Berbati Valley,Greece

Abstract

This research explores temporal patterns in the procurement of raw materials for ceramic production, based mainly on material recovered in regional survey. The underlying premise is that potters in different cultural phases will preferentially exploit the same geological landscape for the most suitable raw materials, but different materials may be preferred depending upon the potter's technological traditions. A program of petrographic and chemical analyses was carried out on ceramics from the Berbati-Limnes Archaeological Survey, Argolid, Greece. Ceramic fabrics from several cultural phases were studied and compared with patterns of settlement within the valley. The results show that ceramics from regional surveys can be used to identify broad patterns of change in exploitation of the same landscape. In some cases these patterns correlate with changes in settlement and may indicate that different choices in raw material procurement mark the arrival of potters from outside the valley.     

Economics and environmental change during the Late Mesolithic and Neolithic periods — investigations in the valley of the Gieselau near Albersdorf,Schleswig-Holstein,Germany

Abstract

Interactions between people and the environment have resulted in constant changes in relief and soil conditions since the Neolithic. Soil transport and degradation had considerable effects on human land use. Extensive field investigations (excavations, auger sampling), measurements (e.g. texture, pH-value, C_org, N), datings (¹⁴C, pottery), together with extensive literature searches in different scientific disciplines (archaeology, palaeoecology, palaeoclimatology etc.), made it possible to reconstruct the Holocene landscape development in four study areas along the valley of the Gieselau near Albersdorf (Schleswig-Holstein, Germany). Stratigraphies were established in the study areas. This paper describes landscape developments around Albersdorf and in northern Central Europe during the Late Mesolithic and Neolithic. The compiled data for the landscape and land-use history serve as a basis for the design of the extensive Archaeological-Ecological Centre Albersdorf (AÖZA) — occupying a site of approximately 40 hectares — using reconstructed features from the Neolithic landscapes.     

Editorial: Palaeolithic America

Abstract

We present the results of the Cerro Jazmín Archaeological Project, a mapping and intensive survey project of a hilltop urban center in the Mixteca Alta, Oaxaca, Mexico. Our archaeological and geomorphological investigations reveal a long history of intermittent occupation with the time of maximum occupation, the Early Postclassic, corresponding with soil formation and landscape stability. Our population estimates are compared with agricultural production projections to assess the city's capability to feed its population and we argue that it functioned as an agricultural center. In a broader discussion of landscape and urbanism, Cerro Jazmín's managed labor was needed to build, manage, and maintain its terrace systems. Our findings show that large urban populations do not necessarily cause environmental degradation.     

Partial reburial of West Ruin at Aztec Ruins National Monument

Abstract

Aztec Ruins National Monument is a World Heritage Site in northwestern New Mexico, USA. More than 50,000 visitors come to the site each year, specifically to visit West Ruin, a 12th–13th century, multi-storey Ancestral Pueblo an (Anasazi) village with over 400 rooms. West Ruin was excavated in the early 1900s and was intentionally left exposed for public access and interpretation. The walls, constructed of shaped sandstone blocks set in mud mortar, have gradually deteriorated, despite years of stabilization and preservation efforts. In 1999, park management began to partially rebury portions of West Ruin as a reversible long-term preservation treatment. While partial reburial allows for presentation of the site to visitors, it also results in uneven fill levels in many rooms. Differential fill levels can increase the area subject to migration and capillary rise of moisture through the walls, and can accelerate stone and mortar deterioration on the exposed wall faces. Differential fill levels can also lead to structural instability from unequal pressure exerted between filled and non-filled areas. To mitigate moisture migration and structural instability from differential fills, a soil retention system was designed and tested using layers of synthetic three-dimensional earth confinement cells. This paper discusses the design and implementation of the soil retention system within the larger context of a multi-phased reburial project underway at Aztec Ruins National Monument.     

HOLOCENE ACCUMULATION OF COLLUVIAL AND ALLUVIAL SEDIMENTS IN THE WEIßE ELSTER RIVER VALLEY IN SAXONY,GERMANY*

Geoarchaeological investigations at two archaeological excavation sites lead to new results with respect to the Holocene landscape development of an archaeologically important loess landscape of Central Europe. Colluvial and alluvial sediments were sampled during archaeological excavations on the valley edge of the Weiße Elster and dated by means of ¹⁴C, TL and dendrochronology, and on the basis of archaeological finds. Thus, for the first time, the development of a valley edge of a river in the Leipzig area, which has been continuously settled for 7300 years, can be reconstructed. The first soil erosion on the valley edge is established towards the end of the Atlantic period. During the High Middle Ages, a colluvial sediment developed. Its deposition time can be limited to between ad 1000 and 1100. The flood loam near Großstorkwitz, which can be stratified by means of the soil and colluvial deposits, originated in the late Sub‐Boreal and early Sub‐Atlantic, as well as after ad 1100. During the first millennium ad, a soil developed in the older flood loam, which indicates a phase of reduced flood loam sedimentation.     

The Case of the Caldwell Mound: A Woodland Period Mound in the Central Scioto River Valley

ABSTRACT

This article presents a reconstruction and analysis of the Caldwell Mound located in the central Scioto River valley of southern Ohio. The mound contained a log tomb, at least four burials, and associated funerary objects. Four AMS radiocarbon dates place the Caldwell Mound within the last century BC and first century AD, and the mound contains evidence of practices historically associated with “Adena” and “Hopewell.” Few other records exist from this period in the region despite it experiencing perhaps some of the most dramatic socioreligious transformations in precolumbian North America. This analysis documents early evidence for the diversification and segregation of leadership roles based on the interpretation of three buried individuals. It also demonstrates the utility and efficacy of working with amateur-produced records and collections, even when incomplete, to reconstruct and glean insight from important Woodland period sites.     

Monitoring of soil moisture in backfilled soil for conservation of an Ancestral Pueblo an great house in Chaco Canyon

Abstract

An automated monitoring station, with climate sensors and a three-dimensional array of soil moisture sensors, was installed to document moisture-content changes in backfilled soil covering an Ancestral Pueblo an ‘great house’ at Chaco Culture National Historic Park, New Mexico, USA. The objective was to evaluate the performance of a geomembrane installation in the soil. Prior to its installation of the geomembrane, we observed that precipitation in winter and spring penetrated only 60–90cm into the fill during the first year after backfilling. A significant amount of moisture evaporated from the surface during the summer months, consequently the driest region was at the surface. In the following twenty-four months we observed continued dissipation of the trapped moisture towards the surface. The installation of the geomembrane system during the second year maintained a stable and dry soil environment, indicating effective surface removal of precipitation and preventing moisture penetration deeper into the soil.     

Ecological changes induced by prehistoric man at pitstone,buckinghamshire

This paper describes the study of a buried palaeosol of post-glacial age stratified between a periglacial coombe rock and a ploughwash deposit. Soil analysis (lithology and mineralogy) and molluscan analysis demonstrate a sequence of woodland, woodland clearance, and tillage. Radiocarbon assay of charcoal from the buried soil gave a date of 1960±220 bc which may date the clearance phase. The soil profile is part of a palaeocatena, the Mollusca from a drier phase of which have been published in an earlier paper. It has therefore been possible to check the relationship of the molluscan assemblages to the buried soil types and it is shown that both the morphology of the palaeosol and the composition of the fauna vary according to their position on the buried landscape.     

Bairaki–a lower paleolithic site on the lower dniester

Findings of excavations at a Lower Paleolithic site, discovered in 2010 near Dubasari on the Lower Dniester, are described. Earlier, two sites with Lower Paleolithic fl int tools – Dubasari-1 (Bolshoi Fontan) and Pogrebya – were found nearby. The cultural layer, located in the top of the lower buried soil overlying the alluvial deposits of the sixth or seventh terrace of the Dniester, included a few stone artifacts and a fragment of an animal bone. The likely age of this buried soil is estimated at ca 500 ka by geological methods. In the alluvium gravel of the same terrace downstream, three pebble tools including two choppers made of a strong Cos?u?i sandstone, and four fl int pieces were found. Geological observations suggest that this alluvium is more than 800 ka old. So far these are the earliest stone tools discovered in a stratified context in the Russian, Moldavian, and Ukrainian parts of the Russian Plain.     

Imaging skeletal remains with ground-penetrating radar: comparative results over two graves from Viking Age and Medieval churchyards on the Stóra-Seyla farm,northern Iceland

Detailed ground-penetrating radar surveys were conducted at separate Viking Age and Medieval churchyards on the Stóra-Seyla farm in Skagafjörður, northern Iceland. Surveying over a previously unknown site (ca. AD 1000) that is located just a few meters above the Skagafjörður valley bottom delineated the remnants of a buried circular turf wall that encloses a church structure and several graves. The radar profiles over the graves contain strong hyperbolic reflections that emanated from the skeletal remains. Over one of the graves, an air-filled void within the chest cavity had been detected as noted by reflections with normal polarity which indicated a boundary towards increasing microwave velocity. During excavation, the soil surrounding an intact rib cage collapsed thus confirming the presence of the void. In general, the skeletal remains were very well preserved and yielded strong reflections which permitted the orientation of the body to be determined. Conversely, the radar profiles over a grave from a more recent churchyard (ca. AD 1200) show ground disturbance but lack hyperbolic reflections. Upon excavation, only teeth were recovered. The poor preservation of the skeletal remains is attributed to increase contact with infiltrating groundwater from an overlying gravel layer. Interpretations were aided by time-slice overlay imaging, forward modeling and analysis of the reflection coefficient.     

Monitoring through replication: Design and evaluation of the monitoring reburial at the Laetoli trackway site

Abstract

How is it possible to monitor the condition of a site or artefact after it has been reburied? In the case of the reburial of the extremely fragile and remote site of Laetoli in Tanzania this problem was addressed by creating a replica reburial close to the site in 1995. The method and materials used to rebury the trackway are replicated in the monitoring trench, which thus provides a ‘window’ on the condition of the trackway. A series of samples and indicator objects of different materials placed in the trench are intended to provide an understanding of the burial environment over the long term. Additionally, triangular recesses with sharply defined edges were cut into the floor of the trench to allow determination of the mechanical stability of the tuff to deformation under the reburial overburden. The trench was lined with root-inhibiting Biobarrier® geotextile and then reburied in the same manner as the trackway; existing acacia trees at the edge of the trench were allowed to remain. In 1997 excavation of part of the trench was undertaken. Of particular interest was the fine detail of the topography of the floor of the trench and the effectiveness of the Biobarrier®. Geosynthetics showed no evidence of deterioration, but severe degradation of all wood samples without preservative chemical treatment and of indicator objects indicated a very aggressive environment. Many of the findings, such as survival or deterioration of the indicator objects, use of geosynthetics and the efficacy of Biobarrier®, have relevance to a broader understanding of buried environments.     

The Historic Landscape of the Saga of the People of Vatnsdalur: Exploring the Saga Writer's Use of the Landscape and Archaeological Remains to Serve Political Interests

Abstract

The saga of the People of Vatnsdalur (Vatnsdaelasaga) provides a case study for a new approach to the Sagas of Icelanders (Íslendingasögur). This treats the saga as a cultural product of the 13th century that can give insights into its creator's ideas and worldviews. Fieldwork at five sites in the Vatnsdalur valley in NW Iceland seeks to establish what these places were like in the 13th century. This knowledge, alongside the saga and place-name evidence, illustrates how the saga writer, presumed to come from a powerful 13th-century family, systematically used the landscape and archaeological remains in the valley to serve his political interests when describing 10th-century events.     

Testing flora as bioindicator of buried structures in the archaeological area of Maxentius’s villa (Rome,Italy)

The flora of the archaeological area of Maxentius’s villa (Rome) was tested as bioindicator of buried remains of masonry and pavements. A total of 53 floristic surveys provided the occurrence of each species in sample units, as well as some their phenological features. The data were elaborated through multivariate statistical analysis in order to assess floristic affinities/differences among sample units, and define their ecological characteristics. The fuzzy set methodology was applied to evaluate relation between floristic richness, plant cover and soil depth. Results showed that the buried remains of stonework create a discontinuity in the ground, influencing the flora growing above it. This phenomenon may give rise to differential presence of some species (e.g., Cota tinctoria, Trifolium scabrum ssp. scabrum on thin soil; Ranunculus bulbosus, Trifolium pratense on deeper soil), but will not have such a great effect on floristic richness. The bioindication of this phenomenon also occurs through phenological irregularities in single specimens and changes in plant cover. Nevertheless other environmental factors (soil moisture/aridity, trampling, enrichment of nitrogen, cutting, ground depression) can interfere with the use of plants as bioindicators of buried structures. It is therefore necessary to consider other factors ecological influencing each site when you want to use plants as bioindicators in archaeological prospection.     

位置照片表征的景区游客拍照行为时空模式

基于九寨沟景区的地理标记照片数据,利用Voronoi图、点中心度和马尔科夫链方法,从景点、景段和风景线尺度分析游客在景区内的拍照行为模式。根据数据呈现的时间转移峰值特征和空间转移概率特征,将景点尺度下的游客拍照行为总结为邻近快速转移、多中心慢速转移、跨越缓慢转移3种模式,景段尺度下的游客拍照行为总结为单向快速转移、跨越慢速转移两种模式,风景线尺度下的游客拍照行为总结为直接快速转移和间接慢速转移两种转移模式。景区内时空转移模式整体上呈现邻近景点、景段之间的空间转移概率较大,出现拍照高峰的时间较为接近,转移概率较高的区域都集中在热度较高的景点、景段,研究结果可以为游客规划游览路径提供理论依据,为景区管理人员提供决策支持。