SciBlogs

Archive 2012

3-D X-Ray is Big News for Archaeological Research Brigid Gallagher Sep 13

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ArtInfo has released an article today which has me very excited, and thinking of ways it could be used in New Zealand archaeology.  

Instead of having to consolidate (or glue together) a fragile pot, urn, vessel, or block of loose soil,  with low concentrate adhesives, co-polymers, acrylics and the like,

And then slowly micro-excavate the contents inside by hand (with really small tools, a delicate hand and meticulous recording) with a 2-D x-ray image or CT-Scan at your side to guide the operation.

This extremely cool piece of kit designed by Nikon to check the condition of turbine blades for Rolls Royce airplane engines is now being used by archaeologists at the University of Southampton to blast not one, but multiple rays  at an object, subject or material from different angles….before it has been excavated. 

Image above: Courtesy of University of Southampton

The reason this is so great? 

A 3-D image is produced giving multitude amounts of new information on one photographic image.  It gives the person about to excavate or  conserve the vessel and its contents maximum information before going in. Information like;

  1. What is in the soil block, urn, pot, basket, gourd, or skin?
  2. How have the contents been arranged?  Have they been dumped randomly, perhaps quickly?  Or have they been methodically placed, with time available for their arrangement?
  3. Is there more than one type of object, subject or material preserved?  Were they put in at the same time, or different times?  Are they in layers that show the order they were placed in the vessel? 
  4. Is the excavation and conservation or restoration strategy being proposed the right one?  Will the contents fit through the mouth of the vessel, or will the side need to come down forst, and then be rebuilt?
  5. Is this a genuine archaeological artefact, or a fake or a hoax?

The archaeologist or conservator can immediately see the true form of the contents,  its survival and condition…and in the case of this story the writing is on the wall…sorry, coins. The words and faces found on the Roman coins tell the date of the object…which gives the terminus post quem, or the date after which the object could have buried, hidden, or lost.

 

Above: Image of Coins 3-D X-rayed by the Nikon technology. Image courtesy of Southampton.

The use of these kinds of technologies are a great time and money saver, as well as allowing the experts to work out whether a vessel is worth opening…and this decision can take into account;

  • the value or rareity of the contents,
  • the cost for its conservation,
  • the long term use, display or storage of the contents,
  • the research potential the contents have (will they push forward our knowledge of past people and practises) and
  • often most importantly consider the respect and dignity that should be given to the vessel and its contents.  

And super importantly;

Because the multiple rays create an image that non-specialists can actually see and often immediately recognise, the value of the artefact can also sky rocket.  Managers, funders or the public for instance can visualise and understand what they are looking at without heavy explanations and a series of photos that require piecing back together in their head.  Its the same reason I also love 3-D laser scanning. 

It makes the past way more accessible.

The Problem with CT Scans and Conventional X-ray?

Nothing at all….but

CT scans produce a highly informative 2-dimensional visual cross section through archaeological material or objects at high resolution.   

The problem can be that to build up the true and accurate picture of the object or subject, a single slice is not enough.  You need numerous slices to see the story in front of you in its entirety. Much like when we get put through the scan for medical reasons.   This also makes it expensive and sometimes more difficult to manipulate the data during the analysis phase of an archaeological investigation.

X-radiography (my favourite trade tool) also produces a 2- dimensional image which can be very informative, but you need to rely on the experience of the operator to set the right parameters to get the information required. 

Depending on the strength and exposure time of the x-ray information is seen, or not.  This is partially determined by the density or molecular structure of the material being x-rayed.  Too many kv’s, for too long often mean the rays go right through an object missing it altogether showing a very black image.  

It has the same effect of setting the depth of field on a photographic camera. An x-ray image is really a compression of 3-dimensional information into a 2-dimensional format, not a single slice of true data coming from a CT Scan.  The good thing is that with the advent of digital x-ray units, it is alot easier to try out different exposures in one session. Better than going off to the dark room to develop your film, and then find out there is no picture! And probably most importantly it is quite economical.

Why am I so excited about this?

I can’t remember the amount of times I have come away from an x-ray session and wished for just one more image from a slightly different angle, or a slightly different exposure,

And then looked at CT Scans and thought agh, too many cross sections!  My head hurts putting this altogether again. 

Technologies that make an object and their contents visible at high resolution mean maximum information to make more informed decisions and greater appreciation value…and that means there is lowered risk of damage, and heightened appreciation of archaeology in the future.

To Destroy, or Preserve? That is the Question on the Effects of Volcanism in Archaeology Brigid Gallagher Aug 16

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In front of me a volcano is erupting. 

This is a slight exaggeration…but from my window last Friday, I could see a long low trail of ash from White Island spread above the horizon, and small billows of white changing form where another burst of steam spews forth.

I have been fighting the urge to go and buy a stronger set of binoculars in case I miss something. 

I have always been fascinated by volcanoes.  It started in earnest during 5th form geography when my teacher Sally Brodie (I really should thank her!) picked up the phone in her office and rang eminent geologist Sir Les Kermode.

The conversation went something like this…

“I am with a student who feels that she cannot fulfil the requirements of her project on the Tongariro Volcanic Field because she cannot adequately explain the difference between andesitic and rhyolitic volcanoes”.

Hmmm, maybe I was a little precious?!

And so I was given this lesson over the course of the next minutes, and I went away a well informed school girl who felt able to finish her assignment.

It was an invaluable lesson, and demonstrated early on that asking the right people the right questions was key to my understanding of science.  Especially when understanding physical sciences where I needed, and still do, need to visualise processes.

But back to volcanoes…and leap forward a few years…what on earth is an archaeological bod doing reminiscing about a desire to be a volcanologist?

Volcanoes have had, and continue to have a huge impact on archaeology in term of;

  1.  Site formation,
  2. Site damage and destruction,
  3. Site preservation and,
  4. Site dating.

…And as a conservation specialist, which is all about understanding the condition and decay mechanisms at play between materials and the environment, volcanic activity is also really exciting;

One single volcanic event can result in site formation, damage, destruction and preservation to different degrees, with long term implications and management needs. 

Assessing and understanding the complex behaviour between the negative and positive effects of one natural disaster, or moment in time, is for me is really interesting because the myriad of problems and solutions that are generated.

Archaeological Examples

Pompeii in Italy has probably made its fame by the effects caused on the Roman town by the eruption of Mt Vesuvius in AD79.  Whilst ash and molten rock formed a covering over the town, its quick cooling resulted in a protective layer to be created taking the form of the object, structure or person it covered.  In many cases this created an air tight capsule in which food stuffs, plaster and paint, human skin and bone, bricks and mortar could be preserved in a relatively pristine manner. Without the preserving qualities of the ash layer, Pompeii it could be argued, would have gone the way of so many other Roman towns, and now be another deteriorating archaeological site in Italy that relies on the tourist dollar, and requires huge amounts of money to help it stay in a state of semi restoration.  Though this has been the very subject of some recent media coverage.

…Luckily for the Romans they built in brick and stone.

New Zealand’s equivalent may well be Te Wairoa in Rotorua. However, buildings and structures of New Zealands prehistoric and historic past have been traditionally made of plant and tree materials such as raupo, punga, kauri and pine.  Placed under the pressures of dense volcanic ash layers, and in combination with the low ignition point of these materials, hot ash and molten rock in many instances has meant fire and destruction, not preservation.

…which has meant loss to the archaeological record.

Though in saying that…should you get a chance to visit The Buried Village at Te Wairoa you would be in for a very nice surprise with some whare that have been carefully excavated and restored, following preservation by volcanic ash. 

This a good example of how volcanic activity has both destroyed and served to keep a site in stasis until rediscovery or excavation. 

A form of time capsule was created.

One of New Zealand’s other big preservation stories as far as archaeology goes is the Sunde site on Motutapu Island. Located in the Hauraki Gulf and joined to Rangitoto Island (Auckland’s youngest volcano, dated at c. 1400) by a land bridge at low tide, Motutapu boasts preserved footprints due to the blanketing effect of Rangitoto’s last volcanic eruption and ash cloud.

Human and dog footprints found side by side are an evocative reminder of real people and animals living in New Zealand some 550 years ago.  Dated at c. 1450AD the foot prints show at least 8 people, 3 of which are children walking with their dogs.  Eruptions and ash fall from Rangitoto sealed the footprints, preserving them like the Laetoli footprints found by palaeontologist Mary Leakey’s team in Tanzania in 1976, and dated to 3.6 million years. 

Discovered in 1981 by archaeologist Reg Nicol, at that time from Auckland University, the ash had a preserving quality for the footprints, but archaeologists believe that it was also responsible for the destruction of settlements, gardens and forests on the Island.  Archaeologist Andy Dodd wrote in his Heritage Assessment “Motutapu Archaeological and Historic Landscapes” for the Department of Conservation (2008);

“The eruption smothered Motutapu in ash and caused widespread deforestation, but also produced friable soils suitable for gardening [and therefore aid regeneration]”.

Once again the destructive and preservative qualities of ash has been recorded by archaeological investigation. 

Its a strange balance that exists between materials and the environment. 

Depending on the perspective or the question there is different degrees of formation, damage, destruction and preservation contained within one volcanic event and ash dispersal.  

And the unfortunate aspect of volcanism is that often scientists don’t know what the ratio will be until the top has blown! Including near Pompeii, where a super volcano has recently been reported.

Never the less, next week we are going on long anticipated family holiday to the Central Plateau.  Hopefully there will be a quiet period of sun and snow… and I will only have to imagine the alternative.  But I think I will pick up a good pair of binoculars on the way…just in case!

Refs:

Te Wairoa – The Buried Village

Motutapu archaeological and historic landscapes heritage assessment, DoC, 2008

The Motutapu Restoration Trust – Sunde Site

Pompeii online

 Note – this is a huge subject of which only a small portion has been considered here…and may be returned to in the future… 

 

Ground Truthing Archaeological Evidence at Castle Howard Brigid Gallagher Aug 06

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‘I am looking for archaeological evidence [before I believe it]’ says field archaeologist Phil Harding during a  recently aired Time Team episode.

On a site where archaeological remains are suspected,  archaeologists go equipped with information ranging from maps, plans and sketches, to remote sensing technology , specialist expertise and experience, but none can guarantee the survival, location or form of  human activity until the ground is dug.

Archaeologists get a true and accurate picture of time and place by gathering the evidence in the ground to understand past activities. Deciding which ground and how much of it is a fundamental decision for most archaeological projects due to value, time and cost pressures.

In this case Phil was referring to archaeology being excavated at Castle Howard in Yorkshire.  I remember this site fondly as it was the second shoot that I ever did with TT.  It is memorable equally for the stunning location, the novelty of a film shoot and the archaeology.

Castle Howard

On the surface this was a no-brainer of a site. Still in the ownership of one family, the Howards, who had held the land since the early 1700’s, they were in possession of plans and maps dating back almost that long suggesting any archaeological evidence remaining in the ground should be easily found.

 The Domesday book (1085AD) records the site as a Viking village called ‘Hildreschelf’.  The Time Team were able to access descriptions of the people and the village.  Again, the various elements of the village should have been easy to locate.

But when it came time to put in the trenches that would find the archaeological evidence of the original settlement on the estate, it proves difficult. 

The Techniques

The geophysical survey team used resistivity (measuring differences in ground density) and magnetometry (measuring changes in ground magnetics) to see if they could see evidence of structures and features in their results.   But the results were inconclusive showing lots of noise in areas and multiple targets for investigation in others.

The maps, plans and sketches were drawn at different scales also generating multiple targets on the ground.

The landscape topography didn’t give many clues because it was clear that during the development of Castle Howard the site had been literally levelled removing many tell tale signs of evidence remaining beneath the ground.

Target 1

During a search for the original church the different techniques came up with different ‘best’ targets. And so Phil says….I want to see the ‘physical evidence’.

Geophysical survey offered 4 good looking responses.  One response with 2 straight lines and square angles, and a concentration of noise was chosen as a good choice for a trench.  The map evidence also suggested the church was in this general area, within 20m…which is pretty good for a lawn as big as Castle Howards. 

David Thorne one of the field archaeologists at the time opens the trench…hotly anticipating the results.  Finds dating to the right time period or a structure would have been good.

….But nothing.  Orange-brown sandy loam by the looks of it on our tv.  Not a hint of a cut, fill, masonry, artefacts, or a stratigraphic profile…the layers of time under the ground.

Target 2

In the walled garden, once a place for growing plants and fruits of warm climates, the search continued for the remains of the homes of Hildreschelf villagers.  It was thought the central road to the village extended into the walled garden and homes lined the road.  This meant that any remains of the Viking village would be found below under the layers associated with the post 1700 garden.

Geophysics suggested a wall may survive which acted as the first target, but much of the garden was full of ‘noise’ – a jumble of unreadable responses.  This was to be expected as the ground has been heavily disturbed as a tropical garden.  Heated piping was run under the earth to warm it and hence encourage growth of such fruits as pineapple.

Myself and Kerry Ely started the trench, removing garden soil to find an edge to a road, and the likely position of any remaining houses – and so I decided to extend the trench.

Underneath the geophysical survey noise was the base of a building, a straggly row of wooden stakes and evidence of a door.  All that survived was the very bottom of many features that were only just holding on in the earth by a few centimetres – all the evidence that was left of a family home.  The rest had been destroyed from above. 

The remains were so slight that the responses in the geophysical survey data had masked the remaining archaeological evidence, hence maps and careful excavation were needed to re-discover them, and prevent them from remaining lost.

Reasons for Trenches

Phil was right, there is nothing like excavation to establish once and for all if something exists.  You cannot rely on the documentary evidence or survey evidence alone. 

And this is the thing…

  1. Map scales and sketch plans are notorious for not translating well onto the actual ground.  There are big disparities between historic maps and actuality.  There wasn’t digital technology, satellites and lasers. There is inbuilt error to many historic documents using rulers, compass and pencil.  And the error increases with time as the maps are reused and translated. 
  2. Documents are often simplistic and the information can be biased to the creators perspective.  They may also reference physical elements that no longer exist.
  3. Modifications to the landscape and environment over time will either preserve or not the evidence of the past.  Massive changes to landscape occur with the laying out of large estates such as Castle Howard, taking away ‘lumps and bumps’, removing traces of previous uses and layouts.  As Mick Aston says at the episode end, this change was often used as a large stamp on the landscape to denote power and subjugation of a people.
  4. Geophysical survey has its own inbuilt set of problems.  A main one being:

It is not a magic tool. You cannot wave the equipment over or into the ground and selectively see only archaeology.  The technique is non-selective, in that it picks up built structures, internal features…AND, natural geology and geomorphology for example.  It can also mask evidence that only just remains in the grounds, and requires excavation more careful in nature.

For a large part its reliability as a tool for decision making in archaeology is only as good as the person analysing and interpreting the data being generated.

Belief in the Archaeological Evidence

Phil Harding is not alone in the opinion that it is necessary to see the archaeological evidence in the ground to confirm its existence.  On most sites it is the only sure way of establishing if the assessment, analysis and interpretation is correct. The expertise of a field archaeologist is to bring together all of the information that the ground retains, and produce interpretations and conclusions grounded in science and fact. 

Sometimes it is called ‘Ground Truthing’, and the sentence speaks for itself. 

 

Grizzly Beastly Magically Science Stories in Museums Brigid Gallagher Jul 31

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Of late I have been caught up with young children and the real world of a heritage conservation and archaeology business. But now I am back and wanted to kick off  with some thoughts about a small museum. One that is fairly typical of many we have visited and have littered about NZ.

 This weekend I was seduced by a heritage museum website.  It reeled me in with ‘Family’,’ Hands On’ and ‘Re-created’– good graphics, pleasing colours, black and white photos of people from the past….

And so I dragged my family along. To be fair, I did not have to do much dragging…we are always pleased to find a new place to visit.  As far as we knew this museum had been closed, was now under new management in place, and had reopened, revitalised…with a new enticing website.

But why o why were we so disappointed?! Again!

Poor presentation. Poor communication.  Poor interpretation.  Again.

The bones were there, in fact they had a good chunk of muscle on them too.  But the volunteers of this community owned museum, who should have been the flesh on this really really nice collection of historic artefacts and paraphernalia on display let it down!

Instead of adding the colour, the texture, the elasticity to the flesh of this collection, we came away feeling tired , dehydrated and not inspired to return! 

While many may roll their eyes at the idea of visiting what they belief to be a collection of nik naks and collectables their parents and grandparents once used….they could be best serve as the storytellers of science for New Zealanders. 

The science of our human history – technology, industry, biology, physics, chemistry, arts and crafts.

There were stone toki (adzes), moa bones and gizzard stones, grammar phones and records, slide viewers and cameras, a bush walk and birds (unfortunately no sound), a fake cow that once passed milk, a telephone operators system, ye olde doctors bed, a re-created kitchen and all the tools and a tractor.

These are the raw ingredients for grizzly beastly magically science stories…the kind that kids and adults enjoy.

Who cannot resist horror stories from the original doctors bed, touching gizzard stones straight from the innards of moas and the magic of early film projection?

Grizzly Baby Bottle Science

A story with massive science potential for me had the baby (dolly) in its pram with a self warming glass water bottle beneath. 

-          The bottle itself was an interesting shape (they ranged from banjo or violin shape, with flat sides to the much safer banana shape in the early 20th century),

-          The origins of the practise would have been interesting (the first in the United States was patented in 1841) though artificial feeders have been documented long before this.

-          The fact a baby sat on it in her pram fascinated my children ….

but the really gorey and sciency storey is the one about the rubber tube that the baby would have had to suck on to get the milk. 

The Baby Bottle Museum  in the UK says that only 2 out of every 10 children survived under the age of 2 in the late Victorian period in England due to the inability to clean the tubes and the point of attachment with the bottle adequately.  These banjo shaped bottles went from being known as ‘Mummies darling’ to ‘The Killer’.

Why?

The lack of sterilisation, bacteria build up, poor general hygiene, bottle reuse…Child health and hygiene is a great message to send out to the young, or young at heart.

Its history, its science and its relevant at the same time!

The message ‘isn’t it neat’ you too can keep your milk [milo] warm by lying on it through the day or night does not cut it…I kid you not!

And the reason we got to lift the baby and discover this story? Quite frankly it was apparent that our kids were beginning to annoy the woman…and so she showed them something!  Smack my brow with a rubber tube! 

Demonstrate, communicate and interprete for the client works!  They were immediately quiet and captivated – though heaven help the collections mangle under the enthusiastic arm of our 5 year old a little later.

The point of this dialogue is this:

-          That for a museum that advertises itself as one where you can handle the collections without the ‘evil eye’ of attendants upon them, we were closely monitored and not allowed to walk through the museum alone (even though the artefacts were stuck down, and the attendant unable to answer basic questions).

-          That appropriate presentation, communication and interpretation panels are fundamental. Select your stories, make them memorable.  A glass bottle made from molten sand that burns red hot like lava to make the shape is a lot more exciting than a rare bottle from Germany to 5 year old and a 35 ish year old.

-          That to get science across in a way that is generous and exciting, you need to have time to explore and be excited, not forced into a monotonous dialogue  by a volunteer security guard, masquerading as ‘passionate about our heritage’ .

-          That science and history intermingle  ALOT. It is time to give new meaning to old subjects, and science just might be a way to do this.  

It is not intended that this entry is a negative one, because the museum content we saw was very good with masses of potential.

But the overwhelming disappointment that the front face of the heritage was clearly not using the collection to stimulate the minds of society, and help heritage become relevant…meant that the renovation was only skin deep and is not likely to lead it into a more appreciated attraction.

I suspect that the use of science communication could be the answer to heritage communication problems.

And just a quick footnote from a lover of all things heritage… when did it become necessary to make the cafe and shop bigger than the whole museum, when surely the collection is the draw card.

New Evidence of Controlled Fire Use by Ancestors, 1 million years ago, at Wonderwerk (Miracle) Cave, South Africa Brigid Gallagher Apr 03

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Ask anybody today what the fundamental requirements of life are, and they will tell you….food, shelter, lighting, warmth, their iphone…

Ask anybody in prehistory what the fundamental requirements of life are, and they may tell you….food, shelter, lighting, warmth…

And for most of this, until recently, that meant fire. 

Fire to protect, Fire to cook, Fire to see, Fire to sustain. And at times, it was Fire to communicate.

Scientists and archaeologists have today released in the Proceedings of the National Academy of Sciences that humans, or rather hominids, our direct ancestors, were able to harness and control fire approximately 600,000 years before previously accepted dates.

New evidence is pointing to a new date of 1 million years ago (1Ma).

The article, here, goes on that it has generally been accepted that Homo erectus was cooking food at approximately 1.9Ma, however there has been little archaeological evidence to support the controlled use of fires to prepare food prior to consumption at this date.  The earliest confirmed site has been known at Qesem Cave in Israel, and dated at 0.4Ma, 400,000 years ago.

Until now…

In the ongoing academic debate of whose site is oldest, earliest and shows best evidence of, or similarity to, modern humans, Francesco Bernaa, Paul Goldberga, Liora Kolska Horwitz,  James Brink,  Sharon Holt,  Marion Bamford,

and Michael Chazang have offered up the latest method to better understand the inhabitants of the Early Acheulian (or Early Stone Age) period at Wonderwerk Cave in South Africa, and their manipulation of fire.

There have been other claims of controlled fires in the early Acheulian period in the recent past such as at Koobi Fora, Gadeb, Chesowanja in East Africa, and Gesher Benot Ya’akov in Israel, but todays authors suggest that the previous studies lack context that can be gained through morphological studies.

Using Fourier Transform Infra-red Micro-spectroscopy (mFTIR) and Micromorphological analysis the researchers have been able to observe and characterise sediments at the microscopic level, that until recently has not been possible. 

The result being that the presence and nature of burnt bone and plant ash in the cave site of Wonderwerk, translated as Miracle Cave, has enabled this staggering shift back in time.

The control and manipulation of fire is considered a major evolutionary step for humans, before which it is thought we used fire generated through naturally occurring events, such as lightening, scrub fires, and natural combustion due to chemical reaction, such as with the self ignition of guamo ( bird or bat droppings).

Wonderwerk Cave

Wonderwerk Cave in South Africa, seen above, is a natural solution cavity which in 2008 was celebrated as the earliest site in the world to reveal evidence of human occupation in a cave, dated to 2 million years by Professor Michael Chazin, see here.   Stone tools found at the base of the caves archaeological strata supported this and were attributed to the Acheulian period (or early Stone Age), approximately 1.7-0.8 Ma. 

The cave was extensively excavated by Peter Beaumont of McGregor Museum from 1978-1993, and rock art has been recorded at the entrance.

 11-17620large4

Inside Wonderwerk Cave.  Left,  Credit: Image of Wonderwerk Cave. (Image courtesy of M. Chazan.)

 

In the article released today, the researchers claim that the combined use of mFTIR and analysis of the micromorphology has revealed deposits from Stratum 10 that contain:

*  charred bone heated to at least 500 degrees C, and

*  angular/sharp edged, complete and incomplete bone that suggest deposits have not moved far

*  exceptionally preserved plant remains suggest deposits have not moved far, and

*  charring  or burning is most likely to have been caused by local combustion

 

  

Stratum 10 samples were studied macroscopically as well as microscopically, showing that:

*  in one area of the cave the frequency of burnt bone reached 80%,

* FTIR (Fourier Transform Infra-red spectroscopy) revealed burning occurred between 400 and 700 degrees C,

* artefact analysis supports controlled heating in one area of the cave with banded iron stone artefacts and manuports displaying pot lid fractures (an often thermally induced fracture which creates a shallow bowl shaped depression in the parent rock which occurs at temperatures in excess of 500 degrees C),

* heat affected clays that support localised in situ burning over a wide area within the cave

The Layers of Strata Inside Wonderwerk Cave.  11-17620large3Below, Credit: Image of Wonderwerk Cave. (Image courtesy of M. Chazan.)

  

In essence the researchers appear to demonstrate undisturbed archaeological contexts and deposits across a widespread area within the cave that contain evidence of ongoing, or repeated cycles of burning or fire making…but with no evidence of a fire surround, hearth structure or pit in which to contain the fire.

What’s to say that Stratum was not blown in by a mighty wind, washed in by a flood or heavy rain, or the product of an ancient ground disturbance which has affected the dates? 

Two reasons, from what the article says:

  1. 1.  The micromorphological evidence, and the way the dateable materials and artefacts were laid down in the earth,
  2. 2.  Crucially, the security of the layers seem to be intact, with Stratum 10 sandwiched between earlier and later Acheulian deposits that display no signs of heating, dispelling a possible counter argument for a later episode of combustion whose heat could have modified this Stratum.

  

 

Good Science Practise?

The article released today also highlights the importance of cross examining archaeological evidence, by more than one method of analysis, when attempting to establish dates that require microscopic and molecular level technologies. 

This includes using analytical techniques such as mFTIR, Thermoluminescence, Potassium-Argon (K-Ar) dating, and combining it with, for example:

-          Examination of the stratigraphy at the microscopic scale,

-          Establishing if the deposit is natural or anthropogenic in origin (the product of or affect by humans),

-          Establishing the past environment of the fire

-          Establishing the security of a site or deposit (that is to establish if the deposit has been contaminated or disturbed in some way through natural processes, chemical change and biological influence) is also considered by the authors as crucial, in setting the dates apart from other sites that have generated earlier dates than 0.4ma through other analytical methods.

Whatever the lesson is to be learnt regarding good scientific practise, the results of this latest study has big, and potentially exciting implications for the future.  By knocking 600,000 years off the closest confirmed date for cave dwelling fire users, It both opens up the race to re-examine past sites using different techniques, and holds the door wide open for future dating analysis.  

 

  

  

 

Auckland Museum Research and Scholarship Medals, and the future Research Centre Brigid Gallagher Feb 29

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During a night of celebration, expectation and promise at the Auckland War Memorial Museum, the Trust Board and key figures at the Museum, including the recently appointed director, Roy Clare, re-instigated the Auckland Museum Medal Awards. 

Lauded as a return to the original intent of museums, to care for and conduct research on its collections, there was a distinct feeling of change for the better amongst the speakers. 

Four eminent New Zealander’s who have dedicated of their lives to excellence in research and scholarship were recognised with all involved in some way in the furthering our understanding of the history and heritage of New Zealand.

Those honoured were:

-          the late Dame Judith Te Tomairangi o Te Aroha Binney, author and historian

-          Professor Russell Stone, historian and professor emeritus at Auckland University

-          the late Professor Roger Neich, ethnologist at the National Museum Wellington and lately of Auckland Museum

-          Dr Nigel Prickett, archaeologist, became an associate emeritus of Auckland War Memorial Museum

Each of these people have been major contributors to New Zealand’s science and humanity sectors, with the relationships, traditions and material manifestations of the Maori world and Pakeha central to their work. 

I was very honoured to be invited to see Dr Nigel Prickett receive his award.  He was the first person to take a punt on me as a 19 year old wannabe archaeologist when he took me on to volunteer in the archaeology department. This ultimately led onto the next 4 years with the collections, and my first job after graduation.  I know first hand from experience the value of working with and handling the museum’s amazing collections, as well as being surrounded by a wealth of knowledge from the different domains of science.  It has been inspirational, and confirmed for me the potential museum collections have with the right guidance and enthusiasm.

Equally fantastic was hearing the stories of the recipients, such as a rousing and passionate speech by Dame Judith Binney’s partner Sebastian Black, Professor Stone who played homage to New Zealand’s participation and loss of life in the World Wars of the 20th century, and the wife of Roger Neich who focused on his love of family, rather than the respected scholar.

Sir Peter Gluckman was the key note speaker demonstrating his usual flare for communicating his vision for the future of science and  museums.  Whilst he continued his theme on the use and value of complex science, he advocated the advancement of science, in all its manifestations, defining it as a high value component to a world class city, to which Auckland should now be striving.

He also caused considerable thought around the inherent risks generated through decision making involved in the presentation of science and knowledge.  Using the concept developed by Funtowicz and Ravetz, his discussion on the principles of post-normal science where evaluation of value, evidence and relevance…including uncertainties…was thought provoking, and a paradigm that allows museums to create exciting research opportunities and best engage with communities through knowledge and display.

This is a recognisable quality of many of the physical sciences, including archaeology, geology and biology, where the assessment and evaluation of risk, probability and value are key components, but has at its foundation knowledge, facts and measured base line information.

Whilst it may appear that post normal science stems away from the notion that science is static with pre-determinable data, Gluckman was under no illusion that excellent research, scholarship and knowledge was at its heart; principles that were on exemplary display by the awardees.

In his final summation, to the effect that museums should be seen as repositories for the future, not the past.  That they are a place of life, not a mausoleum, Gluckman resonated the announcement later in the evening that the Auckland Museum is committed to launching a Research Centre in the near future. 

The Auckland Museum Research Centre has been heralded as a facility to underpin its renewed value placed on science and knowledge.  Once a bastion of research, the collections number into the 3 ½ million mark and Mr Clare was loud and clear in his desire to better utilise the collections available. 

     -   To use the collections to make new discoveries,

     -  Encourage new research such as that conducted at the Kermadec Islands last year to record marine and study its marine life, and Ahuahu in February this year by archaeologists with Auckland University,

     -  Use the collection to engage with Auckland and the global population

The Executive Summary of the Auckland Museums 2012-2013 Draft Annual Plan backs this up, and seen online here:

Establish a Research Centre in Partnership with other Educational and Cultural Institutions, adding strength to the stewardship of out collections and reinforcing the city’s positioning as a ‘learning and innovation cradle’.

Curator of Archaeology Louise Furey has said that ‘In essence it should provide a platform where the museum can work with external collaborators on research and will enhance the reputation of the museum and its collections… the museum and its board is recognising scholarship and research as an important part of the credibility of the museum.’

This is all good stuff, and I just hope it can deliver.

Excavations at First Mission Station (1814) and Prehistoric Garden Island Brigid Gallagher Feb 22

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A very important part of being an archaeologist is to leave the theory books at the desk, and go out into the field.  Whilst grounded in science, archaeology is underpinned by an understanding or a willingness to understand and appreciate culture, society and politics of past human inhabitants. 

Archaeological fieldwork and excavation is integral as it provides the raw data for analysis,  but the process itself requires time to gain confidence to dig through the layers, and understand the significance and potential of each layer. 

This week and last, Otago and Auckland University students have been out experiencing excavation, for many the first time, with University staff and other archaeological professionals. The two field schools have been investigating two very different historical and cultural landscapes in the North Island – but each equally interesting for different reasons.

Unfortunately I have not had the opportunity to visit either of these excavations but like anybody else with access to the internet, I have been kept up to date and informed with team members producing regular updates on their blog sites.   

The fact that blog sites are being set up alongside normal recording systems definitely reflects changing dynamics within archaeology and the increasing desire and call to publicly share information and results.

Oihi Mission Station 1814-1832

The joint Otago University and Department of Conservation field school is sited on the Oihi Mission Station, located in the Marsden Cross Historic Reserve in the Bay of Islands.  On the western side of the harbour leading into Paihia, Russell (Kororareka) and Waitangi this is an immensely important site within New Zealand as our first permanent European settlement site.   The background to the reasons for the excavation, and what is hoped to be achieved is here.

The excavation blog that was produced by DoC archaeologist Andrew Blanshard ran from February 7th to 15th, and he writes that it is pertinent that the excavation began the day after Waitangi Day, an integral day in the marriage of Maori and Pakeha in New Zealand history. 

Oihi Mission Station     The site of Oihi Mission Station  

Other key note first for New Zealand history are:
          1.  On Christmas Day 1814, the Rev Samuel Marsden preached his first sermon on this land, and is shown below in a painting of this day with Marsden at the podium and to his right is Rutara dressed in British reglalia (Alexander Turnbull Library).  The 2ooth anniversary of this event is upcoming in 2014.
 

          2.  The mission is home to New Zealands first European style school, which the archaeologists believe they have found.  Artefacts that support this include many slates and slate pencils.

Speaking to one of DoC’s archaeologists who had been on site for the first few days by phone, I was struck by the excitment in her voice at the structures and artefacts she had seen and was hearing about.  The stone foundations of two buildings plus their nails, an intact hearth from a once vibrant, warming fireplace inside one of the mission buildings, a toy cannon last played with by a child over a 150 years ago, flint used to fire muskets, and the possibility of earlier land modification on the site in the form of Maori terracing.  A bronze bracelet has also been discovered. 

To view pictures of some of these go here.

Being as this is the first settlement in New Zealand, it is not difficult to imagine the strange but wonderful mix of two cultures at this time.  A point at which modern New Zealand begins its journey with the site of these excavations being a pivotal transition point in New Zealands history.   The reserve is definitely worth a visit!   This is a site that I will want to read more about in the future as the post excavation analysis and subsequent stories of the people associated with the mission unfold. 

                                     And in a different landscape completely…

Ahuahu (Great Mercury Island), c. 1300′s? –

The Auckland University fieldschool is underway on Ahuahu (Great Mercury Island) off the Coromandel Peninsula, with Auckland Museum archaeologist Louise Furey and Ngati Hei  A pristine Island, there is a long recorded history and evidence of Maori gardening and settlement, including Pa. The aim of this fieldschool is to reveal more about gardening practises on the Island through New Zealand prehistory and archaeology that is eroding out of one of the dune systems.

What I really like about this blog, is the information about the excavation methodology and strategy are interwoven with the personal thoughts and activities of the writers, mainly of whom are students on the island to learn.  The reflexive quality of this type of archaeological recording adds an interesting perspective to the excavation process, and itself becomes data to be potentially considered later in the post excavation phase of analysis.  

Having worked within this method of archaeological recording while working at Catalhoyuk in Turkey, its advocate Prof. Ian Hodder of Stanford University, has  utilised this theoretical concept to both critically examine Catalhouyk which at its origin is Neolithic, some 9000 years old, and better integrate, or eliminate, the cultural or subjective perspective individual interpreters of archaeological information bring to the analysis and interpretation of sites…whilst maintaining excavation strategies founded in good scientific practise.

      Excavation in Building 77 - 4040 Area

Excavation and discussion on Ahuahu this week                                Excavation and discussion at Catalhoyuk

Whilst the Ahuahu site is being dug over a week or 2, and Catalhoyuk has a 25 year working visa, the mention in the blog site of Ngati Hei representatives, Peter and Peter Johnson whom I met recently on an excavation in Hahei, brings to mind the positive and informative discourse and multivocality (lots of voices and opinions) that can occur between science and humanities through archaeology.  With, in the main, more reasoned and satisifying conclusions.

The blog also lists some fundementals in the science of archaeology which form the basis for the sites intepretation such as the;

          -  soil levels and its relationship with the gardening structures,

          -   stratigraphy, survey and the importance of scale and accuracy in drawings,

          -  the structures, housing platforms, stone alignments, pits, stone faced terraces…the features for analysis

What information comes along post excavation will be very interesting indeed…once again archaeological analysis, intepretations and stories, based on the evidence collected in the field, are what often bring alive the people and places of the past after the thrill of discovery is over.

UPDATE

Updated DoC blog: the second week of the Oihi Bay/Marsden Cross Mission Station excavation is now here…rain, an occupational hazard of archaeology has been causing problems and excitement.  Finding in situ wood, the remains of New Zealands first school house, is certainly a highlight!  Found in the foundations for the building, the archaeologists have been able to start piecing together the stratigraphy of the site….the order in which soils, buildings, their construction  and layers containing evidence of human occupation were laid down.

Minimise the Pain! Archaeological field work techniques, Part 2 Brigid Gallagher Feb 17

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In Part 2 of my crib sheet to help the aches and pains of archaeological fieldwork…         

          3.  Hoeing – it is all in the abs!

Forget the gym, this is the ultimate abdominal work out.  Whilst hoeing looks as though it is another shoulder and arm action, to get effective hoeing in anything other than sand, its the abs that need to take the brunt of it.  At the end of a good session of hoeing your arms should be aching from your triceps down to the wrist, and the stomach muscles even worse. 

The hoe edge should be parallel with the ground, then with a small forceful down ward pressure drag back…clenching the stomach  muscles and triceps to keep the hoe from bouncing up again.  It may only mean a few mm’s are scraped away but the effect should be a clean surface over a larger area very soon. 

Working in lines across the site the waist will also be worked… the more the front stomach muscles hurt, the more you turn sideways onto the hoe to use the waist muscles.  The only minimiser of pain that comes to mind is to spread the feet one in front of the other with the front thigh absorbing some of the pressure being exerted. 

So the conclusion is there is no way to minimise the pain, enjoy it, and know that there will be rewards when you next try on clothes that are slightly too small!  And if you do it enough, one day there will be no pain, and a well cleaned trenched in a short time…ready for an archaeologist with a fab body to investigate the features and produce great photos.

         4.  Brushing – Flick, flick, flick.  Tap, tap, tap…its in the wrist.  

There is nothing worse than looking at an area or structure that has been brushed clean and the features or details are not visible, the colours are dull and there are specks of dirt, mortar, sand etc across it.  For 1. it is a waste of any pain felt, and 2. you just have to do it again.  Double the pain!

Essential during cleaning of many structures and hard surfaces so many people use the whole arm to brush the dirt, moving from the elbow, rotating the shoulder socket.  This action involves the movement of the whole arm causing more strain on the upper back and shoulder than a flick or tap technique.  Dragging the brush along the surface of any archaeology churns up new surface dirt, or redeposits it from another part of the brush. 

To really clean a surface, structure or a vertical section firmly place the bristles (or slap the bristles) on the surface being cleaned, rotate the wrist 90 degrees and flick the wrist up taking the loose dirt with it.  The more you get sprayed with the dirt being removed, the better your technique.  

Flick, flick, flick the horizontal surfaces, and tap, tap, tap the vertical sections or walls…this technique loosens and dislodges the offending dirt and specks and helps them fall to the ground…keeping the colours fresh and the details visible. 

Using the wrist to brush instead of dragging the arm means alot less muscle action and usually means you only have to brush the area once, not go back for dirt that has been reapplied or missed.

But remember on a vertical section to start brushing at the top!  Move the dirt down the surface to the base…once, not over and over again. 

           5.  Cleaning the section – Verticality is the ultimate goal 

Mantra: Not everybody is good at cleaning a section or baulk.  Hands up… I am one of them.  But with practise I should get better. 

Cleaning a vertical section has so many benefits that it is worth going through the physical rigour, and mental pain!  

                              a.  reading the stratigraphy is so much easier

                             b.  dimensions are accurate

                             c.  section photos are so much better, as the lens has the ability to exaggerate any poor excavation.

                             d.  the site looks clean, and if you ever need to go back to an area to check your layers, contexts, profiles or strata it does not generally have to be cleaned up again….except in sand, gravel or other loosely compacted or fine grained sites.

The technique: attack with the cutting edge of a small spade in a diagonal direction from the top of the section, whether there is archaeology at that level or not.  It will all be studied and recorded. Follow up with short jabbing movements with the pointed end of the trowel down the section or continue diagonally.  Finish with the straight edge of the trowel across the face of the vertical section to clean and define if the substrate allows it.

Clean, short, sharp movements with the back side of the spade parallel with the side of the trench will save time and get to the essence of a section – it has to be vertical.  Not bowed, wiggly, wider at the top, sloping to the base…vertical.  The eaiest way to avoid this is to look at the section face diagonally from the top.  Close one eye if need be.  Its very easy to produce a section that slopes in at the base if you are always looking straight on at it.

This is not always comfortable working; the muscles between the shoulder blades generally hurt, but there is some satisfaction in the initial attack at the top edge. The wrist and forearm take the main brunt of section cleaning when working with the pointed end of the trowel to clean around stones and artefacts protruding from the face, and your knuckles can get ripped and bloody.

Changing hands and shaking out the fingers is the best remedy (with some well positioned band aids).  This is one of the main causes of claw hand because of the tension of the muscles between the hand-wrist-forearm, and and a regular change in movement (hence the shake out) is important.  If you have shaky hands at the end of the day…more micro pauses are required.

          6.  Crouching, bending, kneeling – do what is comfortable, but always bend through the knees.

Its an age old story, but bending with your knees is a real saviour in archaeological fieldwork, especially in the long term. 

The other is to watch and learn from cultures that squat.  The skills of squatting are the same as crouching; mastering this means long hours of comfortable archaeology.  The body gets itself into a comfortable position with minimal inpact on the joints and muscles.  It takes practise, but on site squatting competitions can improve skills.  In British archaeology it is a sin to sit while excavating, and kneeling is only just tolerated by some…crouching and squatting is an essential skill. 

Long hours of crouching can lead to stiffness when unfurling the body again, and the top of the back across the shoulders can ache.  Aching shoulders can be helped by releasing the trowel or tool in use and letting your arms go soft on the ground beside or in front while remaining in the crouch position. Gently moving the head from side to side can also help.

Sometimes you just have to kneel.  Aching thighs and calves can be relieved and the tension across shoulders is relieved.  This is best on the knees in sand and other soft soils…but whatever the surface being kneeled on, in time you will get knee callouses if you do not have a kneeling mat.  Kneeling mats are sometimes seem as the soft option, but why have callouses if you don’t have too?

          7.  Conclusions?  I am getting older, my body is getting older…its time to take care of it.  But mostly my mantra regarding archaeological fieldwork is….

NO PAIN, NO GAIN!

At the end of a day, soak in the bath or stand in a hot shower.  Let the water run over you from head to toe….and at the end of an excavation…massages and facials are definitely required.

And do not leap into trenches.  My physio will be able to best say why.

Minimise the Pain! Archaeological field work techniques, Part 1 Brigid Gallagher Feb 16

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In December my youngest daughter turned 2.

Whilst this is not so extraordinary, for me it feels we are at a major milestone…a point where she is making the transition from my baby, to my little girl. 

She suddenly says everything at full volume, punctuates her feelings with a very big, growly ‘NOOOO’ and when you try to help her she responds ‘me do it’, with the hint of a whine.

She also loves her time at day care, has a best friend to whose house she is quite happy to play at without mum or dad, and at least knows what the toilet is, and what she ‘should’ be doing on it.

So while she is quite happy to be racing ahead into the next big adventure in her young life, its also forcing me into the next phase of my life (collective sigh please)…and quite basically that means….

Back to work!

…. with new brain matter that needs to be stimulated and old matter that needs a bit of jigging up.

My organisational skills are also getting honed again…though over the past number of weeks this has meant that by evening when I generally write Digging the Dirt, you would have found me cast on the couch wondering how long can I hold out to bed without being labelled the household bore.

But mainly I have discovered,  work means pain!

My once active, outdoorsy body which could dig, trowel, crouch, shovel, leap, push and bend for hours in all weathers,  has a few new muscular aches and groans.  The old claw hand has not returned but the muscles in my lower back, shoulders and knees are letting me know they are alive and kicking….and have been under used lately.  

So after a few weeks of fieldwork,  I have gone back to basics and thought about the physical movements used in archaeological field work, and how best to use the body and reduce stress on my muscles and joints…plus get lovely neat sections and trenches. 

And this is Part 1 of the crib sheet I am creating:

  1. Shovel throwing — its a flick of the wrist, not an arm swing from the shoulder.  

Bring the loaded shovel or spade up and push out from the body, followed by a short jerk of the wrist when the dirt is at the apex of the movement. While the head of the shovel or spade is held up the dirt is released into the air.  This has 2 positive effects.

      -      The bicept and wrist takes much of the load, rather than the upper back, making it a more efficient swing which can be continued for longer through the day.

      -      The deposition of the dirt is more precise.  As the dirt leaves the shovel it maintains itself as a single mass until it drops neatly on to the spoil heap or into the wheel barrow.  The dirt is not sprayed all over the trench surface.  The further the elbow is extended from the body, the further the dirt will travel after the wrist jerk.

Practise makes perfect and it was a common competition on UK archaeological sites to show who could throw further, with the least spill of dirt, and at the chosen target.  The wheelbarrow, for example, would then be moved further and further away, up to 15 m or so at times. One of my good friends and past adverseries, Phil Harding on tv’s Time Team,  sums it it up rather nicely in this youtube clip I found while researching excavation techniques.  He always did pip me at the post…and does love his shovel, as you you will clearly see.

YouTube Preview Image

         2. Trowelling -  take control of the trowel, it is not fragile

The flat edge of the trowel is firmly placed parallel with the ground.  With a small downward movement  the trowel is then brought for a short distance back towards the body, and a slice of dirt can then be flicked off.   

Down, trowel, and flick!  Repeat. 

This is generally a movement in the wrist, with the addition of some broad sweeps of the entire arm.  Trowels should not be dragged through dirt, unless the substrate is sand, then a cutting or slicing action is used. 

This technique creates a clean surface with fresh colours to view, not sprinkled with dirt that has fallen over the trowel edge due to too much dirt being moved at once, or the dragging the dirt over the cleaned layer ‘fuzzying’ up the colours or features.

Trowelling can be painful!  The greater the compaction of the ground, the more downward force you need to put on the trowel, the more it is felt in the wrist.  Muscular pain in the forearm is common, but by using a wrist flicking technique rather than whole arm movements the muscle strain in the upper arm can be minimised.

                  3.  Mattocking – trust the mattock!

Using the forces of gravity, the mattock descends from height with minimal downward force.  As the flat end meets the ground it is ideally at right angles to the ground.  This technique means the mattock should stop when there is a change in resistance in the subsurface strata, primarily due to changes in composition and densities, and therefore define events and cultural layers. 

This theory does not work in sandy sites, and cannot be maximised when the ground is full of stone and rubble

By using a descending pendulum action the body exerts less effort and energy, and is able to find a working rhythm. This technique can be continued for a much longer time than when force is also put into the downward stroke and you actively attack the ground.  There is relief for the body when the mattock head is pushed up to full height and left to fall naturally to the ground for the next strike. 

It is also amazingly accurate, and with experience stops at the next chronological layer in the ground.

This technique also means less pain.  The natural gravity dependant method causes musular pain at the top of the arms, shoulders and upper back.  When the mattock is also forced down into the ground the aches and pains spread into the mid and lower back, plus the buttocks as you absorb the force of the downward strike and impact.

Next time: Hoeing, brushing, section cleaning and crouching, bending and kneeling

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