304 research outputs found
Local and exotic sources of sarsen debitage at Stonehenge revealed by geochemical provenancing
The application of novel geochemical provenancing techniques has changed our understanding of the construction of Stonehenge, by identifying West Woods on the Marlborough Downs as the likely source area for the majority of the extant sarsen megaliths at the monument. In this study, we apply the same techniques to saccharoid sarsen fragments from three excavations within and outwith the main Sarsen Circle to expand our understanding of the provenance of sarsen debitage present at the monument. Through pXRF analysis, we demonstrate that the surface geochemistry of 1,028 excavated sarsen fragments is significantly affected by subsurface weathering following burial in a way that cannot be overcome by simple cleaning. However, we show that this effect is surficial and does not have a volumetrically significant impact, thus permitting the subsequent use of whole-rock analytical methods. Comparison of ICP-AES and ICP-MS trace element data from 54 representative sarsen fragments with equivalent data from Stone 58 at Stonehenge demonstrates that none are debitage produced during the dressing of this megalith or its 49 chemical equivalents at the monument. Further inspection of the ICP-MS data reveals that 22 of these fragments fall into three distinct geochemical ‘families’. None of these families overlap with the geochemical signature of Stone 58 and its chemical equivalents, implying that sarsen imported from at least a further three locations (in addition to West Woods) is present at Stonehenge.
Comparison of immobile trace element signatures from the 54 excavated sarsen fragments against equivalent data for 20 sarsen outcrop areas across southern Britain shows that 15 of the fragments can be linked to specific localities. Eleven of these were likely sourced from Monkton Down, Totterdown Wood and West Woods on the Marlborough Downs (25–33 km north of Stonehenge). Three fragments likely came from Bramdean, Hampshire (51 km southeast of Stonehenge), and one from Stoney Wish, East Sussex (123 km to the southeast). Technological analysis and refitting shows that one of the fragments sourced from Monkton Down was part of a 25.7 cm × 17.9 cm flake removed from the outer surface of a large sarsen boulder, most probably during on-site dressing. This adds a second likely source area for the sarsen megaliths at Stonehenge in addition to West Woods. At this stage, we can only speculate on why sarsen from such diverse sources is present at Stonehenge. We do not know whether the fragments analysed by ICP-MS were removed from (i) the outer surface of Stones 26 or 160 (which are chemically distinct to the other extant sarsen megaliths), (ii) one of the c.28 sarsen megaliths and lintels from the c.60 erected during Stage 2 of the construction of Stonehenge that may now be missing from the monument, or (iii) one of the dismantled and destroyed sarsen megaliths associated with Stage 1 of the monument. With the exception of the fragment sourced from Monkton Down, it is also possible that the analysed fragments were (iv) pieces of saccharoid sarsen hammerstones or their pre-forms, or (v) small blocks brought on-site for ceremonial or non-ceremonial purposes
Holocene history of the 79° N ice shelf reconstructed from epishelf lake and uplifted glaciomarine sediments
Acknowledgements This work was funded by a NERC standard grant (grant no. NE/N011228/1), and some radiocarbon analysis was funded by NEIF (grant NE/S011587/1; allocation number 2169.1118). We thank the Alfred Wegener Institute, particularly Angelika Humbert and Hicham Rafiq, for significant logistic support through the iGRIFF project. Additional support was provided by Station Nord (Jorgen Skafte), Nordlandair, Air Greenland, and the Joint Arctic Command. Naalakkersuisut (government of Greenland) provided scientific survey (VU-00121) and export (046/2017) licences for this work. Finally, we would like to thank our (Nanu Travel) field ranger Isak (and dog Ooni) for keeping us safe in the field and taking great pleasure in beating James A. Smith at cards. Financial support This research has been supported by the Natural Environment Research Council (grant no. NE/N011228/1).Peer reviewedPublisher PD
Knowlton Circles: A Later Neolithic and Early Bronze Age Ceremonial Complex and Its Environs—A Review
The larger henge monuments of Wessex have been the focus of detailed archaeological investigation for over a century and consequently their study has provided a greater, albeit fragmentary, understanding of later Neolithic society. For the most part such studies have continued to show that these great mega-structures of the third millennium B.C. persist as beacons of ceremonial functionality into which later societies invested much of themselves, intellectually, spiritually and unquestionably physically. While Stonehenge, Avebury and Durrington Walls continue to attract a great deal of attention with ongoing research, comparable sites in Dorset have been less well researched. Two campaigns of archaeological investigation undertaken in the Allen Valley of east Dorset by the author have focussed upon the complex of earthworks at Knowlton and additionally at one of three broadly contemporary barrow cemeteries located nearby. The findings from these investigations are beginning to shed more light on the possible origins and development of these important but weakly understood landscapes. This paper outlines some of the main findings from these investigations and posits a chronological framework for the integration of a group of monuments that formed both a ceremonial landscape and a geographical and spiritual home for communities that lasted for a thousand years
"Geomorphological record of a former ice stream to ice shelf lateral transition zone in Northeast Greenland
Understanding ice stream dynamics over decadal to millennial timescales is crucial for improving numerical model projections of ice sheet behaviour and future ice loss. In marine-terminating settings, ice shelves play a critical role in controlling ice-stream grounding line stability and ice flux to the ocean, but few studies have investigated the terrestrial lateral geomorphological imprint of ice shelves during deglaciation. Here, we document the terrestrial deglacial landsystem of Nioghalvfjerdsfjorden Glacier (79N) in northeast Greenland, following the Last Glacial Maximum, and the margin's lateral transition to a floating ice shelf. High-elevation areas are influenced by local ice caps and display autochthonous to allochthonous blockfields that mark the interaction of local ice caps with the ice stream below. A thermal transition from cold- to warm-based ice is denoted by the emplacement of erratics onto allochthonous blockfields. Below ~600 m above sea level (a.s.l.) glacially abraded bedrock surfaces and assemblages of lateral moraines, ‘hummocky’ moraine, fluted terrain, and ice-contact deltas record the former presence of warm-based ice and thinning of the grounded ice stream margin through time. In the outer fjord a range of landforms such as ice shelf moraines, dead-ice topography, and weakly developed ice marginal glaciofluvial outwash was produced by an ice shelf during deglaciation. Along the mid- and inner-fjord areas this ice shelf signal is absent, suggesting ice shelf disintegration prior to grounding line retreat under tidewater conditions. However, below the marine limit, the geomorphological record along the fjord indicates the expansion of the 79N ice shelf during the Neoglacial, which culminated in the Little Ice Age. This was followed by 20th century recession, with the development of a suite of compressional ice shelf moraines, ice-marginal fluvioglacial corridors, kame terraces, dead-ice terrain, and crevasse infill ridges. These mark rapid ice shelf thinning and typify the present-day ice shelf landsystem in a warming climate
Mapping species distributions: A comparison of skilled naturalist and lay citizen science recording
To assess the ability of traditional biological recording schemes and lay citizen science approaches to gather data on species distributions and changes therein, we examined bumblebee records from the UK’s national repository (National Biodiversity Network) and from BeeWatch. The two recording approaches revealed similar relative abundances of bumblebee species but different geographical distributions. For the widespread common carder (Bombus pascuorum), traditional recording scheme data were patchy, both spatially and temporally, reflecting active record centre rather than species distribution. Lay citizen science records displayed more extensive geographic coverage, reflecting human population density, thus offering better opportunities to account for recording effort. For the rapidly spreading tree bumblebee (Bombus hypnorum), both recording approaches revealed similar distributions due to a dedicated mapping project which overcame the patchy nature of naturalist records. We recommend, where possible, complementing skilled naturalist recording with lay citizen science programmes to obtain a nation-wide capability, and stress the need for timely uploading of data to the national repository
Lactational Exposure to Polychlorinated Biphenyls, Dichlorodiphenyltrichloroethane, and Dichlorodiphenyldichloroethylene and Infant Neurodevelopment: An Analysis of the Pregnancy, Infection, and Nutrition Babies Study
BackgroundPolychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) are persistent, bioaccumulative, and toxic pollutants that were broadly used in the United States until the 1970s. Common exposure to PCBs, DDT, and dichlorodiphenyldichloroethylene (DDE), the most stable metabolite of DDT, may influence children’s neurodevelopment, but study results are not consistent.ObjectivesWe examined the associations between lactational exposure to PCBs, DDT, and DDE and infant development at 12 months, using data from the Pregnancy, Infection, and Nutrition Babies Study, 2004–2006.MethodsWe measured PCBs, DDT, and DDE in breast milk at the third month postpartum. Lactational exposure of these chemicals was estimated by the product of chemical concentrations and the duration of breast-feeding. Infant development at 12 months of age was measured by the Mullen Scales of Early Learning (n = 231) and the Short Form: Level I (infant) of the MacArthur–Bates Communicative Development Indices (n = 218).ResultsNo consistent associations were observed between lactational exposure to PCBs, DDT, and DDE through the first 12 months and the measures of infant development. However, DDE was associated with scoring below average on the gross motor scale of the Mullen among males only (adjusted odds ratio = 1.9; 95% confidence interval, 1.1–3.3).ConclusionInfant neurodevelopment at 12 months of age was not impaired by PCBs, DDT, and DDE at the concentrations measured here, in combination with benefits from long duration of breast-feeding in this population
Local and exotic sources of sarsen debitage at Stonehenge revealed by geochemical provenancing
The application of novel geochemical provenancing techniques has changed our understanding of the construction of Stonehenge, by identifying West Woods on the Marlborough Downs as the likely source area for the majority of the extant sarsen megaliths at the monument. In this study, we apply the same techniques to saccharoid sarsen fragments from three excavations within and outwith the main Sarsen Circle to expand our understanding of the provenance of sarsen debitage present at the monument. Through pXRF analysis, we demonstrate that the surface geochemistry of 1,028 excavated sarsen fragments is significantly affected by subsurface weathering following burial in a way that cannot be overcome by simple cleaning. However, we show that this effect is surficial and does not have a volumetrically significant impact, thus permitting the subsequent use of whole-rock analytical methods. Comparison of ICP-AES and ICP-MS trace element data from 54 representative sarsen fragments with equivalent data from Stone 58 at Stonehenge demonstrates that none are debitage produced during the dressing of this megalith or its 49 chemical equivalents at the monument. Further inspection of the ICP-MS data reveals that 22 of these fragments fall into three distinct geochemical ‘families’. None of these families overlap with the geochemical signature of Stone 58 and its chemical equivalents, implying that sarsen imported from at least a further three locations (in addition to West Woods) is present at Stonehenge. Comparison of immobile trace element signatures from the 54 excavated sarsen fragments against equivalent data for 20 sarsen outcrop areas across southern Britain shows that 15 of the fragments can be linked to specific localities. Eleven of these were likely sourced from Monkton Down, Totterdown Wood and West Woods on the Marlborough Downs (25–33 km north of Stonehenge). Three fragments likely came from Bramdean, Hampshire (51 km southeast of Stonehenge), and one from Stoney Wish, East Sussex (123 km to the southeast). Technological analysis and refitting shows that one of the fragments sourced from Monkton Down was part of a 25.7 cm × 17.9 cm flake removed from the outer surface of a large sarsen boulder, most probably during on-site dressing. This adds a second likely source area for the sarsen megaliths at Stonehenge in addition to West Woods. At this stage, we can only speculate on why sarsen from such diverse sources is present at Stonehenge. We do not know whether the fragments analysed by ICP-MS were removed from (i) the outer surface of Stones 26 or 160 (which are chemically distinct to the other extant sarsen megaliths), (ii) one of the c.28 sarsen megaliths and lintels from the c.60 erected during Stage 2 of the construction of Stonehenge that may now be missing from the monument, or (iii) one of the dismantled and destroyed sarsen megaliths associated with Stage 1 of the monument. With the exception of the fragment sourced from Monkton Down, it is also possible that the analysed fragments were (iv) pieces of saccharoid sarsen hammerstones or their pre-forms, or (v) small blocks brought on-site for ceremonial or non-ceremonial purposes
Locating oneself in the past to influence the present: Impacts of Neolithic landscapes on mental health well-being
There are well-established links between mental health and the environment. Mental illness is a global issue, and international policies increasingly focus on promoting mental health well-being through community-based approaches, including non-clinical initiatives such as therapeutic landscapes and the use of heritage assets. However, the empirical evidence-base for the impact of such initiatives is limited. This innovative study, known as Human Henge, used a mixed-methods approach to investigate the impact of immersive experiences of prehistoric landscapes on the well-being of participants with mental health issues. Uniquely, the study followed participants for a year after their participation in the project to explore the long-term impact of their experiences on their mental well-being. Findings highlight that, overall, participants experienced improved mental health well-being from baseline to mid- and end-of programme (p = 0.01 & 0.003), as well as one-year post-programme (p = 0.03). Qualitative data indicated the reconnection of participants with local communities, and with other people, in ways that improved their mental health well-being. These data highlight the effectiveness of using heritage as a means of improving the well-being of people with mental health issues
Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79N) Glacier, North-east Greenland"
The Northeast Greenland Ice Stream has recently seen significant change to its floating margins and has been identified as vulnerable to future climate warming. Inflow of warm Atlantic Intermediate Water (AIW) from the continental shelf has been observed in the vicinity of the Nioghalvfjerdsfjorden (79gg€¯N) Glacier calving front, but AIW penetration deep into the ice shelf cavity has not been observed directly. Here, we report temperature and salinity measurements from profiles in an epishelf lake, which provide the first direct evidence of AIW proximal to the grounding line of 79gg€¯N Glacier, over 50g€¯km from the calving front. We also report evidence for partial un-grounding of the margin of 79gg€¯N Glacier taking place at the western end of the epishelf lake. Comparison of our measurements to those close to the calving front shows that AIW transits the cavity to reach the grounding line within a few months. The observations provide support for modelling studies that infer AIW-driven basal melt proximal to the grounding line and demonstrate that offshore oceanographic changes can be rapidly transmitted throughout the sub-ice-shelf cavity, with implications for near-future stability of the ice stream
The Landscape Archaeology of Knettishall Heath, Suffolk and its Implications
This paper briefly describes the results of archaeological fieldwork carried out in an area of heathland, currently managed as a nature reserve, in East Anglia. Although the earthworks recorded are for the most part unremarkable, they demonstrate the variety and intensity of human exploitation which shaped this ‘traditionally managed’ habitat. They also serve to emphasise the extent to which modern conservation management can radically change the long-term character of individual places
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