| First high-resolution laser survey of ancient site shows importance of solstices and efforts to make those events more dramatic. | ||||||
Thought to have been erected between 4000 and 5000 years ago, the monoliths at Stonehenge are arranged in such a way that they align with the exact position of the Sun as it rises on the day of the summer solstice, and as it sets on the winter solstice. Now, using a three-dimensional laser scanner provided by the German company Z+F, surveyors and archaeologists have discovered that the stones aligned along the north-east to south-west axis of Stonehenge were specially shaped and worked to highlight their particular significance, with the technology revealing features that had previously been thought likely to have weathered beyond all recognition. In its detailed report on the high-resolution survey that it commissioned, English Heritage wrote: “Analysis of the laser scan data has revealed significant new evidence that enhances our understanding of various aspects of Stonehenge, from the techniques employed in construction, through the addition of prehistoric carvings in the Early Bronze Age, to collapse, breakage and the activities of tourists.” According to the report, one of the key results of the laser scan was to reveal that the view of the monument from “the Avenue”, the ancient processional way to the north east of Stonehenge, was particularly important: “To approach and view the stone circle from this direction means that the midwinter sunset had special meaning to prehistoric people, and that they made deliberate efforts to create a dramatic spectacle for those approaching the monument from the north east,” noted the organization. Analysis of the laser survey has also shown that the stones on the outer sarsen circle, which are visible when approaching from the north-east direction, have been completely “pick dressed” – meaning that the brown and grey crust on the surface had been removed, exposing a fine, bright grey-white surface. In contrast, the outer faces of surviving uprights in the south-western segment of the circle were not pick dressed.
The laser scan, which was carried out in March 2011 and analyzed over the past six months, has also revealed dozens of previously undiscovered axehead carvings. Susan Greaney, Senior Properties Historian at English Heritage, said: “We didn’t expect the results of a laser scan to be so revealing about the architecture of Stonehenge and its function.” The laser scanner collected data with a resolution of 1 mm across the entire stone circle, and of just 0.5 mm for four stone surfaces of particular interest. It revealed more than 700 surface features in all, including damage, graffiti and conservation efforts as well as the prehistoric carvings and markings. The analysis is groundbreaking, in that it represents the first time that results of such a high-resolution, sub-millimeter laser scan have been published for a project on the scale of Stonehenge. “Other large monuments have been subject to high-resolution survey, [but] this project is the first attempt at applying high-resolution survey to investigate a monument of this size and importance,” notes English Heritage in its analysis report. “The use of both laser scan and photogrammetric data collection created different data formats that could be analysed in different ways, providing opportunities for comparison between the data sets and numerous options for visualizing the surface of the stones.” English Heritage also says that the suite of techniques developed for the Stonehenge projects can now be used in other conservation projects, including the new method of “luminance lensing”. This approach, which the organization expects to have wide-ranging applications, can be used to analyze detailed data “meshes” of the sort generated by laser scanning.
The laser scan has also helped to shed some light on some of the longest-running controversies between archaeologists regarding Stonehenge. One of those is the suggestion that the monument, with its fallen and apparently missing stones, was never actually completed – a theory that is still hotly debated today, with others believing that the “missing” stones were in fact stolen from the completed circle at various points in time. The theories for the “non-completion” case typically focus on the use of small, irregular and inadequate stones that have since fallen down, the absence of many stones from the south-western side of the monument, and the absence of any evidence documenting the removal of stones. Stressing that the laser scan and analysis only informs (rather than solves) the ongoing debate, the English Heritage report says that new information from that scan “has revealed that significant portions of most fallen stones have been removed from Stonehenge”, adding that “fallen stones were easy prey for stone robbers”. Overall, concludes the report, 27 of the original 30 upright stones of the original circle were “certainly erected”, adding that there is no convincing evidence that the circle remained incomplete. “In the light of the significant degree of stone robbing, it is possible that a complete Sarsen Circle once existed,” it suggests. One thing that does not appear to be under debate is the success of the latest laser scan (Stonehenge had previously been laser-scanned in 2003, but at lower resolution), and how optical technologies can contribute to high-profile conservation and archaeology projects. “By far one of the most encouraging and exciting aspects to this project is that even though Stonehenge has been subject to decades of extensive study, the application of cutting-edge technology has brought significant new discoveries,” the report concludes. Full article: http://optics.org/ Stonehenge Tour Guide |
Stonehenge News and Visitor Information.
Tuesday, 9 October 2012
High-res laser scan reveals Stonehenge secrets
Monday, 8 October 2012
Revealed: Early Bronze Age carvings suggest Stonehenge was a huge prehistoric art gallery
For part of its existence as an ancient temple,Stonehenge doubled as a
substantial prehistoric art gallery, according to new evidence revealed
yesterday.
A detailed laser-scan survey of the entire monument has discovered 72
previously unknown Early Bronze Age carvings chipped into five of the giant
stones.
All of the newly discovered prehistoric art works are invisible to the naked eye – and have only come to light following a laser-scan survey which recorded literally billions of points micro-topographically on the surfaces of the monument’s 83 surviving stones. In total, some 850 gigabytes of information was collected.
Detailed analysis of that data – carried out on behalf of English Heritage - found that images had been engraved on the stones, normally by removing the top 1-3 millimetres of weathered (darker coloured) rock, to produce different sized shapes. Of the 72 newly discovered images revealed through the data analysis, 71 portray Bronze Age axe-heads and one portrays a Bronze Age dagger.
Prior to the laser survey, 46 other carvings (also of axe-heads and daggers) were known or suspected at Stonehenge – mostly identified visually back in the 1950s. The laser-scan survey has now confirmed the existence of those other images and provided more details about them.
The 72 new ‘rock art’ discoveries almost treble the number of carvings known at Stonehenge – and the monument’s largely invisible art gallery now constitutes the largest single collection of prehistoric rock carvings in southern Britain. Although now largely invisible to the naked eye, back in the Early Bronze Age the images, composed of then-unweathered (and therefore lighter coloured) stone would have been clearly visible.
The revelations are likely to be of huge importance to archaeologists’ understanding of a key part of Stonehenge’s life as a prehistoric temple.
It’s known that, when the main phase of the monument was initially built in the middle of the third millennium BC, it was designed primarily as a solar temple, aligned on the mid-winter and mid-summer solstices. But, as Stonehenge evolved over subsequent centuries, the extent to which other religious functions were added is not yet known.
Certainly, in the period 1800-1500 BC, vast numbers of individual monumental tombs were constructed in the landscape around Stonehenge and additional features (various circles of ritual pits) were laid out around the monument. The carved axe-heads and daggers also belong to this enigmatic period - and may signify some sort of expansion or change in the great stone circle’s religious function.
In Indo-European tradition axe-heads were often associated with storm deities – and some surviving European folklore beliefs suggest that upwards-facing axe blades were used as magical talismans to protect crops, people and property against lightning and storm damage. It’s potentially significant that every single one of the Stonehenge axe-head images have their blades pointing skywards, while the daggers point downwards. The axe-heads – the vast majority of the images – may therefore have been engraved as votive offerings to placate a storm deity and thus protect crops.
It may also be significant that the vast majority of the carvings either face a nearby set of tombs (from roughly the same period) – or the centre of Stonehenge itself. Rare evidence from elsewhere in Britain suggests that axe-head and dagger carvings could have funerary associations.
The laser-scan data shows that many of the axe-head images have exactly the same dimensions as up to half a dozen other images in the prehistoric Stonehenge ‘art gallery’. This in turn suggests that real axe-heads were being used as ‘stencils’ to help produce the images. If that’s the case, the largest axe-heads portrayed - up to 46 centimetres long – depict objects which were far bigger than archaeologists have ever found and which must have been for purely ceremonial or ritual use.
The laser-scan survey was carried out for English Heritage by a Derby-based survey company – the Greenhatch Group – last year. A subsidiary of York Archaeological Trust – ArcHeritage, also operating on behalf of English Heritage – then spent many months analysing and cataloguing the vast quantities of data.
“The new discoveries are of huge importance. They also demonstrate how emerging technologies can extract previously unsuspected and crucial information from a monument like Stonehenge,” said Marcus Abbott, Head of Geomatics and Visualization at ArcHeritage.
“As the previously invisible images started appearing on our computer screens, we stared in disbelief at the sheer quantity of carvings being revealed – and treble-checked all our data,” he added.
The survey and analysis has also yielded other new insights into Stonehenge. It’s revealed, through an examination of how finely the stone surfaces were worked, that the entire prehistoric temple was constructed to be viewed primarily from the north-east. That’s the side of the monument which is approached by what archaeologists have long believed to be a processional way, aligned with the solstices.
Because, it now seems that Stonehenge was built to be viewed from that direction, it suggests that some sort of religious procession made its way towards the monument, along that route, probably on mid-winter’s and mid-summer’s day.
Detailed analysis of the data also shows that one of the stones at the now ruinous south-west side of the monument was also very deliberately worked and shaped to allow a line of sight through to the setting sun on mid-winter’s day. This, along with other new evidence, suggests that the south-west side of the monument was once fully functional – and will reduce support for those who have, up till now, argued that Stonehenge was never completed. The implication therefore is that at some stage in its history there was a deliberate attempt at its destruction.
Particularly puzzling is the laser survey discovery that the prehistoric stone masons, who helped create Stonehenge, used two different stone-working techniques. The stone-dressing work on the monument’s great circle (both uprights and lintels) was accomplished by working parallel to the long sides of the stones, while the five stone ‘trilithons’ (the great horse-shoe arrangement of linteled stones) within the great circle were dressed by working at right-angles to the sides of the stones.
This previously unknown fact – revealed by the laser scan operation – suggests that the great ‘trilithons’ may have been constructed slightly before the great circle rather than being contemporary with it.
Full article: - http://www.independent.co.uk/
Stonehenge Tour Guide
All of the newly discovered prehistoric art works are invisible to the naked eye – and have only come to light following a laser-scan survey which recorded literally billions of points micro-topographically on the surfaces of the monument’s 83 surviving stones. In total, some 850 gigabytes of information was collected.
Detailed analysis of that data – carried out on behalf of English Heritage - found that images had been engraved on the stones, normally by removing the top 1-3 millimetres of weathered (darker coloured) rock, to produce different sized shapes. Of the 72 newly discovered images revealed through the data analysis, 71 portray Bronze Age axe-heads and one portrays a Bronze Age dagger.
Prior to the laser survey, 46 other carvings (also of axe-heads and daggers) were known or suspected at Stonehenge – mostly identified visually back in the 1950s. The laser-scan survey has now confirmed the existence of those other images and provided more details about them.
The 72 new ‘rock art’ discoveries almost treble the number of carvings known at Stonehenge – and the monument’s largely invisible art gallery now constitutes the largest single collection of prehistoric rock carvings in southern Britain. Although now largely invisible to the naked eye, back in the Early Bronze Age the images, composed of then-unweathered (and therefore lighter coloured) stone would have been clearly visible.
The revelations are likely to be of huge importance to archaeologists’ understanding of a key part of Stonehenge’s life as a prehistoric temple.
It’s known that, when the main phase of the monument was initially built in the middle of the third millennium BC, it was designed primarily as a solar temple, aligned on the mid-winter and mid-summer solstices. But, as Stonehenge evolved over subsequent centuries, the extent to which other religious functions were added is not yet known.
Certainly, in the period 1800-1500 BC, vast numbers of individual monumental tombs were constructed in the landscape around Stonehenge and additional features (various circles of ritual pits) were laid out around the monument. The carved axe-heads and daggers also belong to this enigmatic period - and may signify some sort of expansion or change in the great stone circle’s religious function.
In Indo-European tradition axe-heads were often associated with storm deities – and some surviving European folklore beliefs suggest that upwards-facing axe blades were used as magical talismans to protect crops, people and property against lightning and storm damage. It’s potentially significant that every single one of the Stonehenge axe-head images have their blades pointing skywards, while the daggers point downwards. The axe-heads – the vast majority of the images – may therefore have been engraved as votive offerings to placate a storm deity and thus protect crops.
It may also be significant that the vast majority of the carvings either face a nearby set of tombs (from roughly the same period) – or the centre of Stonehenge itself. Rare evidence from elsewhere in Britain suggests that axe-head and dagger carvings could have funerary associations.
The laser-scan data shows that many of the axe-head images have exactly the same dimensions as up to half a dozen other images in the prehistoric Stonehenge ‘art gallery’. This in turn suggests that real axe-heads were being used as ‘stencils’ to help produce the images. If that’s the case, the largest axe-heads portrayed - up to 46 centimetres long – depict objects which were far bigger than archaeologists have ever found and which must have been for purely ceremonial or ritual use.
The laser-scan survey was carried out for English Heritage by a Derby-based survey company – the Greenhatch Group – last year. A subsidiary of York Archaeological Trust – ArcHeritage, also operating on behalf of English Heritage – then spent many months analysing and cataloguing the vast quantities of data.
“The new discoveries are of huge importance. They also demonstrate how emerging technologies can extract previously unsuspected and crucial information from a monument like Stonehenge,” said Marcus Abbott, Head of Geomatics and Visualization at ArcHeritage.
“As the previously invisible images started appearing on our computer screens, we stared in disbelief at the sheer quantity of carvings being revealed – and treble-checked all our data,” he added.
The survey and analysis has also yielded other new insights into Stonehenge. It’s revealed, through an examination of how finely the stone surfaces were worked, that the entire prehistoric temple was constructed to be viewed primarily from the north-east. That’s the side of the monument which is approached by what archaeologists have long believed to be a processional way, aligned with the solstices.
Because, it now seems that Stonehenge was built to be viewed from that direction, it suggests that some sort of religious procession made its way towards the monument, along that route, probably on mid-winter’s and mid-summer’s day.
Detailed analysis of the data also shows that one of the stones at the now ruinous south-west side of the monument was also very deliberately worked and shaped to allow a line of sight through to the setting sun on mid-winter’s day. This, along with other new evidence, suggests that the south-west side of the monument was once fully functional – and will reduce support for those who have, up till now, argued that Stonehenge was never completed. The implication therefore is that at some stage in its history there was a deliberate attempt at its destruction.
Particularly puzzling is the laser survey discovery that the prehistoric stone masons, who helped create Stonehenge, used two different stone-working techniques. The stone-dressing work on the monument’s great circle (both uprights and lintels) was accomplished by working parallel to the long sides of the stones, while the five stone ‘trilithons’ (the great horse-shoe arrangement of linteled stones) within the great circle were dressed by working at right-angles to the sides of the stones.
This previously unknown fact – revealed by the laser scan operation – suggests that the great ‘trilithons’ may have been constructed slightly before the great circle rather than being contemporary with it.
Full article: - http://www.independent.co.uk/
Stonehenge Tour Guide
Stonehenge Close up. Led by one of English Heritage’s experts.
Exclusive English Heritage Members' Only Event
Gain a rare and fascinating insight into the famous World Heritage Site with an exclusive tour around the site led by one of English Heritage’s experts. Start the tour with exclusive early morning access to the stone circle at Stonehenge accompanied by our expert. Visit key archaeological sites including Durrington Walls, Woodhenge and The Cursus and learn more about the archaeological landscape and investigative work that has gone on in recent years.
How to Book - 1st November 2012
Tickets are available to book from 10am on Thursday 18 October by calling our dedicated ticket sales team on 0870 333 1183 (Mon-Fri 8.30am - 5.30pm, Sat 9am - 5pm).Member (Adult) £30.00
Booking link: http://www.english-heritage.org.uk/daysout/events/1398933/
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