All good things must come to an end…. An end of season wrap up of Trench 3!

As week eight of the 2015 excavation season comes to its end, let’s reflect back on what we achieved and discovered this season. This blog will come to you in bite-size, area-by-area portions! How handy!

Timber building

One of the first things on our to-do list this season was to continue excavating the timber building. We started exploring the beam-slots to this building back in BC13. Beam-slots, for the confused reader, are trenches dug to contain either a horizontal timber beam to form the foundation of a building, or more likely a series of upright timbers in a construction style called ‘post-in-trench’ by archaeologists.

Understanding the western beam-slot sufficiently to be confident that we had associated the correct linear cut with our building, proved to be difficult, and took a great deal of time.  By the time the 2015 season started, we were finally confident of it, an only the southern part of the eastern beam-slot and the southern beam-slot remained un-excavated. Both these beam-slots could be seen in section thanks to the presence of three of the WWI test latrine pits (which we are pretty sure, were not used for their intended purpose, but do make good archaeological test pits).

The middle section of the southern beam-slot offered a pleasant surprise; two teminals to the construction cut marked a central doorway into the building. Fascinatingly this lay directly in the line of a pebble path in the south east corner of the trench, that ran parallel to our metalworking building (we excavated this a few seasons ago). The association of the two buildings through the presence of the path does not seem too optimistic. This means we can date the new building to the middle 9th century AD, as we a great deal of dating evidence for the metalworking building. .

This discovery motivated us to take some hammerscale samples within the boundaries of the timber building, to see if it had, at some point, been used for metalworking purposes. The low finds recovery from within the building though does make us wonder if it could have had a timber floor, which would make thethe layers within it part of an aerlier phase. Something to work out next year. Either way the sampling will hopefully be informative and not be wasted.

The outline of our new building and the pebble path that assciates it with the metalworing building. Coincidently its entrance lies in the same area as the stone theshold of the overlying large timber hall of probable 10th century date.

The outline of our new building and the pebble path that assciates it with the metalworing building. Coincidently its entrance lies in the same area as the stone theshold of the overlying large timber hall of probable 10th century date (also shown).

Elusive paving feature

You may remember from earlier blogs this season that we excavated a rectangular paved feature, consisting of 3-4 large flat slabs with two vertical flat stones to the north and south. When we originally uncovered this feature in BC13 we briefly interpreted this as a drain-feature, but quickly discarded this theory, as we could trace it no further. Sadly, excavation produced no clear-cut “Eureka!” moment, and it remains enigmatic. Our best guess, based on the realtively central location within the building, is that the horizontal slabs were put into support a large post or beam that was one of the roof supports.

North-west

The north-west corner was mostly left alone until the last two weeks of excavation. When we did return there, our main idea was to dig down two large and deep contexts, not expecting to encounter any features in the process. But as always, whenever you don’t count on finding anything, you do.

Firstly, we finally took down our large ‘jaggedy rock’ context, which took up most of the north side of the NW-corner of the trench. As expected, most of this context went down onto bedrock. However, we also found a small, circular feature consisting of small flat stones, with a diameter of about 45cm. We are choosing to excavate this feature next season, but our current interpretation is that it served as a way to level off the ground with the bedrock to the west.

Also, to the south of the NW-area, we dug down onto a large rectangular stone that looked suspiciously like it was part of a structure. Further excavation showed a line of large stones going east and then making a turn to the south of the trench. This shows that we may be dealing with the corner of a building, that might be largely extending westward outside of the trench.

Image 3 - NW

The stone linear in the NW-corner of Trench 3.

Brian Hope Taylor

This season has also dealt with the partial uncovering of Brian Hope-Taylor’s tarped area. Brian Hope-Taylor excavated at Bamburgh Castle in the early 60’s and early 70’s, and since we are almost down to the same level as the northern part of his trench, we are close to joining up the two excavation areas! BHT left us with some exciting features to excavate next season, including a drain feature and a hearth area.

Eastern side of the trench

In the eastern side of the trench, next to the eastern beam-slot to our timber building, we uncovered a pebbly surface’. As we continued excavation, this narrow strip of pebbles expanded into what we now think is either a pebble path or pebbled surface which slopes down as it extends more eastward. We are still working on finding its southern extent and finding out if it extends west of the eastern beam-slot (which would make it earlier in date than the timber building).

Image 2 - pebble path

Pebble path in the eastern side of the trench.

Lastly, to the north of our pebble context we have located what seems to be a high-medieval pit-feature. We found several shards of pottery from this period, together with two styca’s, finds that shouldn’t be in the same context under normal circumstances. This means that a pit was dug down from above (probably in the 11th-12th centuries), through 9th century layers (explaining the styca’s), which was then filled up with both the Anglo Saxon and high-medieval material. We will finish this pit next season.

So there you have it! Right now we are in the process of finishing off excavation on all the features we are currently working on; namely the pebble path/surface in the east and the potential new structure in the north-west. We will use the last two days of the excavation season to plan and level the most recently excavated areas, finish off all the necessary paperwork, and then, finally, tarp up the trench to protect it from weathering.

Hammerscale Sampling and Thin Sectioning in Trench 3

In the past two weeks, apart from the usual excavation and recording process, Trench 3 did a number of hammerscale samples and two thin-sections, which is quite exciting! Today’s blog is all about elaborating on these processes, so that we may get more insight into different elements of archaeology.


Hammerscale Sampling

Hammerscale sampling is used to find out if a certain area of the trench was used for metalworking purposes. Last week we carried out a small number of hammerscale samples within the borders of our large timber building to see it it has been used for any metalworking.

Hammerscale is created when a blacksmith hammers iron; the sparks that fly off are actually tiny pieces of iron oxide that are only a couple of millimeters in size.

When we take hammerscale samples, we take a planning frame of 1x1m, which is divided into 25 smaller squares of 20x20cm. We then take small samples from each of these little squares. The hammerscale, hard to see with the naked eye, is magnetic, so when we run a magnet through each individual sample, any present hammerscale material will stick to the magnet, which is exactly what we want.

Hammerscale sampling

Hammerscale sampling

When labeling the bags we need to be mindful of the coordinates of each individual sample. We gather this information so that when the samples are processed we can relate them to their position in the trench to see how the concentrations of hammerscale fluctuate throughout the area. In some cases plotting out the hammerscale concentrations can result in a so-called ‘blacksmith’s shadow’; a negative shadow where the concentration of hammerscale is low because that is where the blacksmith was working from, sweeping the hammerscale off the anvil, resulting in a high-concentrated cone-shaped ‘shadow’ forming around the blacksmith.

In our case, we dare not hope to find anything halfway as exciting as a blacksmith’s shadow (though we can always dream!), but finding evidence of hammerscale in our samples would give us some well-needed clues as to what the function of our timber-building might have been.


Thin sections

At the end of week 5, Graeme Young led Trench 3’s staff and students alike in putting in two thin-sections in one of our World War I test latrine pits.

Trench 3 has three WWI practice latrine pits. While it is quite sad that the archaeology in these parts of the trench has been destroyed, it does give us a nice little sneak peek of what we will be excavating in future seasons.

While we as archaeologists can quite clearly see differences in contexts and different occupation layers, there is only so much we can see with the naked eye. While a context can seem fairly homogeneous to us, it may potentially consist of many single events that we are unaware of.

This is where the thin-section comes in. We take a simple metal box, and after preparing the section by cutting it completely vertical, hammer the box into the section.

Preparing the section for the thin-section sample, showing off some beautiful stratigraphy

Preparing the section for the thin-section sample, showing off some beautiful stratigraphy

Removing the thin-section box from the section.

Removing the thin-section box from the section.

After getting the X, Y, and Z coordinates using the Total Station, we then carefully spade it out and wrap the metal box, now containing a nice sample of the vertical stratigraphy, into several layers of cling film, securing the sample into place and making sure it doesn’t get contaminated.

Two succesful thin-section samples

Two successful thin-section samples

The sample is then sent off to the laboratory, where they set the sample with resin, and cut off a thin slice of the sample, which they then study under a microscope. An ash layer which up until then might have been interpreted as a single event may turn out to be dozens of smaller single events!

In Trench 3 we took two samples, slightly overlapping, so that we end up with around 20cm of continuous stratigraphy. The section we have sampled is from the industrial occupation of the trench, potentially spanning a time frame of around a hundred years.

If all goes well, both of these excavation techniques should provide us with some exciting new insights into the function of our timber building and the yet-to-be excavated archaeology in our trench!

Bamburgh Research Project: 2015 Castle Excavation Season Plans

Things are well underway at Bamburgh Castle and the Bradford Kaims. Our supervisors and assistants are busy pouring over last seasons plans and reports. At each site the students were given a fascinating health and safety lecture followed by a tour of the trenches and an introduction to our previous years finds. Soon we will start to remove the tarps! Today we will hear from Director Graeme Young who will give us an in-depth look at the plans for the castle tenches this season.


Graeme Young

DSC06287

I was one of the two archaeologists who wrote to Lady Armstrong back in the winter of 1996, asking for the opportunity to do some research at the castle. It does not seem all that long ago, but mathematics tells me otherwise! A great deal has changed since then but our aims of good research, education and engaging with the public remain at the core of what we do.

Being a Northumbrian born and bread, I have known Bamburgh since I was a child, and working to understand this important site was an ambition since I first started archaeology back in 1987. Its a huge privilege as an archaeologist to have the opportunity to dig a dream site, and one which I have been delighted to share with colleagues and a generation of students. Hopefully through our blog and website and some short films we plan to make this summer, we can share something of the fun and excitement with all of you online.

When not immersed in all things Bamburgh I spend far too much money keeping an ancient Land Rover running.


So what do we hope to get up to this summer?

The 2015 season of archaeological work to be undertaken at Bamburgh will continue to build on previous season’s work within the two major excavation trenches, but this year we will be doing more photogrammetry and also testing a new databasing system.

Trench 1

This year we have the full extent of Trench 1 under investigation. During recent seasons we have been playing catch-up, excavating an extension to the trench down to the same levels that we had reached within the original trench, which extended along the north wall of the West Ward. This sets us up to try and identify post-hole structures. Previously we had identified a number of post-holes, so we are probably overdue identifying the buildings that they belong to. We have reached the boulder clay above the bedrock, which means that it is quite possible we might even be able to identify prehistoric features amongst the structures.

Trench 3

Having investigated the metal-working building at the south of the trench, and found numerous 9th century metal finds, recent work has concentrated more in the north and north-west part of the trench, where a series of structural remains have been identified. All this is part of a plan to make sure that the full extent of the trench is at the same phase. In order to do this we have had to face the difficult problem of understanding a complex stone spread that lay between these two areas. Now we believe this area contained a post-in-trench timber building, also of 9th century date. The complete excavation of this building, and a partially surviving paved surface to its east, will be amongst the main aims for this summer. As part of this process it is quite possible that the level of the northern part of the Hope-Taylor 1970s excavation will be reached this year. A big step forward with our plan to incorporate his excavation into our own in order to publish them together.

Analysis

Of course there is the post excavation recess as well. Every bit as important as the excavation itself. This year analysis of the excavation archive will continue to concentrate on the implementation of the digitisation of the site record. A trial with a server based archive system will be a key part of the programme this summer.


Trench 3 Removes the Metalworking Building

In 2010 it became apparent that we had an Anglo-Saxon structure in the southern part of Trench 3. This building was associated with areas of burning, including spills from probable entrances.

Metalworking building in Trench 3

Over the past two dig seasons we have unearthed all four sides of packing stones for a timber building, as well as a pebbled path that leads to the entrance. We have also sampled the entire area for hammerscale, as we believe that this area was involved in the process of metalworking (Click here to find out more about hammerscale).

Over the last few weeks we have also unearthed a mortared surface within the interior of the building.

The mortared surface in Trench 3

All these features have been photographed, planned and described on context sheets and it is now time to begin lifting and excavating the floor of the building.

Nat and Tom working on the building floor

We began by lifting the northern half of the building walls and today we have begun excavating the mortared surface, taking environmental samples as we go.

To see the first phase of this excavation watch the video below.

Environmental Sampling

A warm greetings from the BRP Environmental team (that’s me, Megan Taylor, Environmental Supervisor)!

The first week of BRP 2012 was dedicated to critical preparation for the coming season. This involved a review of the environmental work completed last year, both the physical processing of environmental samples—flotting, sorting, and discard—as well as the associated paperwork.

This is part of the siraf tank where the fine residue is captured in a sieve for processing.

Megan sorting through today’s samples from the metal-working building.

BRP Enviro sample sheet

The database was updated, new environmental sample catalogue and record sheets were created and printed, and a guide to environmental archaeology at the castle was printed out to aid in the understanding and processing of samples.

In addition to organizing the old environmental sample catalogue and processing records, I set up the flotation tank and ran a “practice sample” through to be sure everything was operating properly. With the aid of some of the Bamburgh boys’ bucket train, some finessing with a bit of broken plastic, and some new clips, the tank now works perfectly. The rain and the lack of drying trays has delayed serious flotting a but a few extremely helpful volunteers have helped make a dent in Trench 7 sample sorting. If work continues as it has been, we should have Trench 7 environmental samples processed and databased by the end of June, leaving me some time to muck around in the trenches. All in all a brilliant start to the season!

In Trench 3 we have been sampling a hearth feature and an ashy spill from the interior of our 9-10th century metal-working building.

Hayley and Helen sampling the burnt clay context from within the hearth.

Hayley and Helen happy at work

Hammerscale Sampling

The final phase of the hammerscale sampling is in progress in Trench 3. Hammerscale is the waste product created when forging metal. In Trench 3 we believe we have a 9-10th century metal-working area based on a temporary structure. The area is rich in metal objects, most of which are damaged, which has led us to believe that the forge may have been used for the re-cycling of metal. The following video explores how we undertake hammerscale sampling in order to map its distribution and the implications this may have for our interpretation of the site.