Skip to main content
Loading Explore guides…
Excavation Before and After · Acedra
Home
Explore
History
Excavation Before and After
Sign in to save
Chat
If YouTube asks you to sign in, open the video on YouTube.
Watch on YouTube
Reload player
Transcript
192 segments
Copy
Hide video
0:02
Jane Harrison: Great thanks carrie and I hope everyone can hear me, and I hope that you can see the screen.
0:10
Jane Harrison: Yes, okay good so welcome, and thank you all for making it through the snow this session is about excuse me, the role of excavation the before and after of a dig So what has to be done before we open the trenches and what happens after they're closed or backfield.
0:31
Jane Harrison: And everything that happens after the dig is imagined stuffy nose and, of course, as post excavation.
0:37
Jane Harrison: I want to say right to the beginning that not all the examples i'm using to illustrate the methods and the principles and the ideas. Jane Harrison: Are from hadrian's wall and war CAP or even from Northumberland, because i'm going to be using some other community. Jane Harrison: excavation projects and research projects i've been involved with to help illustrate I haven't had that much time to collect data.
1:01
Jane Harrison: From wall CAP yet that will change i'm sure and and then in the second session i'm going to look at the actual business of excavating and in between those there is carrie and Mariano Center and just sort of.
1:15
Jane Harrison: Little exercise about. Jane Harrison: Locating trenches and, if you want to join me for half an hour next week. Jane Harrison: We can talk about a bit more about how we decide exactly where to put trenches so what you can see up on the slide is one picture of long running.
1:35
Jane Harrison: Locally routed to research excavation in ot me reopening and for the third season and that's a sequence of seasons. Jane Harrison: And then you can see, Catherine upon hadrian's wall and recording for a small and targeted excavation at war, town cracks and a geophysics plot from a Community landscape project in Oxfordshire.
1:55
Jane Harrison: And, of course, your physics, is one of the things that almost routinely now and, if at all possible is done before we even think about excavation but i'll be coming back to that.
2:07
Jane Harrison: Okay, so we're going to be thinking about the following questions amongst some others excavation is destructive. Jane Harrison: And it's slow and it's expensive and what follows excavation is even more costly and time consuming, so why do we excavate. Jane Harrison: And what should we do what research and investigation should we carry out before a spade, or a bigger bucket even breaks grand.
2:34
Jane Harrison: And what has to happen practically and bureaucratically before that excavation can start. Jane Harrison: And then, what are the sorts of questions and principles that help us decide exactly where we put trenches and and. Jane Harrison: It can be really difficult actually deciding exactly where to put a trench and you'll see what I mean later on and here on the slide you can see. Jane Harrison: Some locals excavating a little evaluation trench.
3:03
Jane Harrison: By a 12th century church in Oxfordshire and that's a trench that is just testing how deep the archaeology is and what sort of condition, it is, and it won't break into. Jane Harrison: intact archaeological lairs but it's a sort of look see and that's sort of is a pre excavation investigation and then you can see, at the bottom of the slide and.
3:25
Jane Harrison: Someone doing ground penetrating radar and other sort of geophysics alongside excavation and that's interesting alongside excavation. Jane Harrison: In Orkney and you can see the beginnings of our turf war that we've built to act as a windshield as well as a way of keeping the terms we've taken off the excavation and location.
3:48
Jane Harrison: Okay, so why do we excavate obviously to find out about the past. Jane Harrison: archaeology is all about the physical remains of thing of things, buildings and landscapes and it's often can be about the the everyday of people's lives in the past. Jane Harrison: So, even in periods and times with loads of documentary evidence archaeology can still challenge assumptions and it can add information.
4:15
Jane Harrison: because it deals with physical surroundings and we know that that our physical surroundings and the objects, we use matter and they say things about us they're part of our everyday life.
4:30
Jane Harrison: And it also helps us discover more about the posters, we live in, now, and to think more about up the pit of where we live and about how our landscapes have been created and on the slide you can see, the big Gray.
4:46
Jane Harrison: picture, with the red dots is part of the results of another he left community. Jane Harrison: Research Project and all the Little Red dots are tiny little test pits one meter square excavations that have been done in people's gardens and in parks. Jane Harrison: Looking for pottery and they show all the cases where Roman poetry has been found and the little diamonds, all the places where kills kills kills Roman Romano British pottery kills have been found in the past.
5:16
Jane Harrison: And that Gray expanse is actually one of the unremarkable suburbs of the city of Oxford so it's outside of the famous historic Center it's an everyday normal suburb covered in houses and little parks, the cali mini factory and.
5:35
Jane Harrison: The the the being involved in digging those tests and then finding out so much more about the Roman landscape that is was part of that was was part of their. Jane Harrison: The landscape in the past, changes the way changed the way for the people who live there, the way they looked at their everyday routes to school and to work and to the shops.
5:59
Jane Harrison: And then another reason why we excavate is that it brings us right up close to actual things like this beautiful little iron age and weaving comb.
6:12
Jane Harrison: or a Roman Cone a Roman Roman coin, or even to the wall itself and we actually have a direct physical contact with our predecessors.
6:24
Jane Harrison: And then one very important reason why we excavate is to do it to keep practicing to to improve our techniques and there, you can see in the top slide some local people doing exactly that, on an iron age site.
6:43
Jane Harrison: And also, we excavate because there are some things that only excavation can provide really good dating evidence and the geophysics results from the site in the top. Jane Harrison: The top side, where you can see people excavating suggested it might be partly Roman and in the event it wasn't it was middle iron age and early Anglo Saxon.
7:07
Jane Harrison: defines, we can only have the fines if we excavate that show us what people were actually doing and only excavation gives us the detailed story. Jane Harrison: of how a site or a landscape has been used and that sequence of change over time buildings being built and used an abandoned or rebuilt, and then we excavate because it's fascinating it's challenging it's outside and it's fun.
7:38
Jane Harrison: But it is also a really serious responsibility and it matters and whenever we excavate, we need to do it for good reasons and with us, you know as well as we possibly can.
7:54
Jane Harrison: Then another reason we excavate, of course, is to record archaeology that's being damaged or in fact destroyed that might be damaged by people by whether or by animals. Jane Harrison: So you can see, the picture on the slide there from damn say in Orkney now that's a tiny it's about a kilometre across tiny uninhabited island.
8:20
Jane Harrison: And we're recording in that picture the remains of a Viking settlement, which is gradually being washed away by the sea where there's no sensible way of protecting it, and the only way of knowing about it is to excavate it and record it.
8:35
Jane Harrison: You can also see water and walton cracks where the weather and livestock and sometimes people are damaging the loose core stones on the top of the wall and.
8:49
Jane Harrison: that's another place where we need to know more about it, and we need to find out ways of protecting it and excavation is another tool in doing that.
8:59
Jane Harrison: And then, of course, we also have to excavate because there's going to be building or development work new houses roads office flops new train routes. Jane Harrison: And even in town centres, there can be surprising little bits of preservation. Jane Harrison: Think about how elements of the of the wall keep popping up in excavations and Newcastle and enabling a slowly to build up a better picture of it.
9:26
Jane Harrison: The rose theatre found in London and here in this picture on the on the slide, this is an excavation. Jane Harrison: In Oxford of on the side of a medieval friary which had already had one shopping Center built built on top of it and is about to have another extended shopping Center built on it. Jane Harrison: But surprisingly even there, there were survivors of beautiful flag floors and earlier landscapes underneath on age and even earlier.
9:58
Jane Harrison: So, since 1990 the 1990s, archaeology has been part of the actual planning process.
10:05
Jane Harrison: And there is a local authority archaeologist and if any building development is likely to discover or damaged or destroyed archaeology. Jane Harrison: Then, there must be archaeological works which are paid for by the developer.
10:21
Jane Harrison: it's called preservation by record, so the only lasting legacy of that archaeology is going to be in the excavation that is done, ahead of the building of whatever it is, so you have to extract as much as much information as possible from those works.
10:41
Jane Harrison: So broadly, we can see them to them basic types of excavation and one is is driven main is driven by research, the university based research or community based run on rooted projects. Jane Harrison: And these projects, usually have identified and archaeological site or a landscape and the have questions that they want to answer.
11:07
Jane Harrison: And that the site's often part of a wider project for example at war time cracks of course that's part of a much wider project and and there we were asking questions about earlier poorly recorded excavation work and about the condition and deterioration of the curtain wall.
11:27
Jane Harrison: At that Oxford your site, one of the main questions and driving the excavation there, you can see, on the top picture and it's an excavation of a nunnery. Jane Harrison: And nothing was known about the early history of the nunnery, and so there was that question to to ask, but also nunnery is a much less well investigated the monasteries and so any excavation of a nunnery adds to the general pool of knowledge about memories.
12:01
Jane Harrison: Now these sorts of research driven projects can be limited by their finances by logistics by access but they're more and more designed by an involved local people and a driven by by specific objectives and and and are contributing huge amounts to what we can learn from excavations.
12:26
Jane Harrison: Now, of course, this does raise the question whether it is right to dig if sites are not threatened that the site at Oxfordshire was was threatened to a certain extent, but not as much say, for example as a site that's going ahead of.
12:45
Jane Harrison: A shopping Center but should we believing this sites for future better equipped.
12:52
Jane Harrison: archaeologists who've got a far better techniques for doing things, but then, how are we ever going to improve our techniques and if we don't get in there and keep practicing. Jane Harrison: And I know myself that I was able to to to really improve techniques and approaches for digging and windblown sand in me and for analyzing phases of Viking, Dr stone wall construction, we could only have done that, by going in and excavating.
13:21
Jane Harrison: And the other broad type of excavation is that excavation ahead of development, and here the location is not chosen because archaeologists want to dig their butt because somebody else does. Jane Harrison: And the most interesting and core part of a site can be just outside the area that's determined for the development and you can't go back and chase that at a later season, it just it's just beyond what you can do.
13:51
Jane Harrison: And these investigations can be very professional and reasonably well finance and tend to be published much more quickly, but are awarded on a tender basis, so can be financially squeezed and negotiations with developers are not always easy.
14:10
Jane Harrison: So the design or However, the design of these explorations is influenced by those local authority archaeologists who have got and have developed research agendas for their own plots.
14:23
Jane Harrison: And perhaps falling.
14:25
Jane Harrison: into the second category are those sorts of rescue excavations where you are getting in there to record as much as possible before a site goes and falls into the sea or is destroyed finally by some other means.
14:43
Jane Harrison: So.
14:46
Jane Harrison: it's it's just worth emphasizing again that, with all these good reasons to dig when we do dig, we have to dig as well as possible and. Jane Harrison: we've got to get the story out there we've got to publish it and get the information out to local people to the wider audiences, who have gotten into an interest.
15:08
Jane Harrison: And, of course, the actual fieldwork and the digging is only one part of the process i'm going to come back to that long lead in to the first day on site. Jane Harrison: But I want to take a moment now to think about post excavation about what happens when you finished on site for every day on the field where we're out there digging there have been many days of preparation and they'll be many, many more days of post excavation.
15:44
Jane Harrison: And this is a process which involves all the elements of an excavation being processed and analyzed and pulled back together to produce a report an article or book a talk. Jane Harrison: It can take years for some of the Multi season research projects and to do all the work and reach some kind of publication, and it has to be admitted that some projects have an appalling record in publication.
16:16
Jane Harrison: So there should be a plan from the outset, you should have an idea about what sort of how you're going to get your story out there in the end, what it might cost what sort of timings you're aiming for, and who needs to be involved.
16:29
Jane Harrison: And the strands of evidence, you need to bring together to do that are considered other great number of them there's all the background research that are going to talk about in a moment.
16:41
Jane Harrison: there's all.
16:44
Jane Harrison: The.
16:46
Jane Harrison: site drawings, which needs to be digitized and and presented in a form suitable for publication. Jane Harrison: The photographs needed to be sorted and that written story of the unfolding of the sequence of events on the site needs to be created from all the details that we've collected on site. Jane Harrison: The written records of every deposit of soil every structure every post all every pits and every ditch.
17:14
Jane Harrison: And, and all the the fines and the samples that are taken away from site needs to be analyzed by specialists and reported on it same sort of you kind of explode the site. Jane Harrison: everything needs to be dealt with and analyze and then you've got to bring it all back together again. Jane Harrison: And the specialist reports can be lengthy the processes, they have to do, can be expensive.
17:40
Jane Harrison: artifacts need cleaning stabilizing and conserving think about the vin de Landa tablets, for example. Jane Harrison: They need analyzing and reporting on by those various special specialists and, of course, because techniques have improved.
17:54
Jane Harrison: That can be involved quite a lot of expense, for example with objects, there are all sorts of examinations, now that we can undertake to do with the way they've been used, you can, for example, analyze residues on pottery to see what sort of liquids or.
18:12
Jane Harrison: or things they've been used for.
18:15
Jane Harrison: And the samples taken in soil need to be taken away because they can reveal all sorts of effects of human activity. Jane Harrison: animal and fish bones and shells need to be looked at human bone if there is any and all the environmental data and the charred seeds the plants, the insects which can be taken from certain sorts of deposits, need to be.
18:39
Jane Harrison: processed and you can see that the person on the slide there is.
18:47
Jane Harrison: Getting a soil sample and saving it through a sequence of steps to get all those tiny little bits of environmental data out of the soils that have been collected carefully on site.
18:59
Jane Harrison: And then of course there's dating and some of those scientific dating methods that we can now apply again are expensive and requires specialist processing and then also quite often specialist analysis.
19:13
Jane Harrison: So all of that takes expertise and expense and sometimes you have to carefully way the relative value of certain things and depending on your. Jane Harrison: The sort of financing that you've got and, as you bring all those outcomes back together again then each strand contributes to that final story bringing in any of your background research and all the pre excavation investigations, you might have done.
19:40
Jane Harrison: although of course it has to be said in archaeology than ever are any final stories and you know that so well from your familiarity with the wall that there are so many debates and. Jane Harrison: New evidence can throw the cattlemen the pigeons and we go on trying to make our stories better as more evidence comes in.
20:01
Jane Harrison: So what sort of research and investigation should happen before an excavation is undertaken.
20:09
Jane Harrison: We always begin work with some ideas about we want, we want to know more about, but this sort of pre excavation phase. Jane Harrison: sharp and settle up and feeds into the decision making process, why the site's important why the excavation needs doing and those questions that you want to answer. Jane Harrison: And there are two main strands of pre excavation work ones, the desk based work and the other is field work, other than excavation.
20:39
Jane Harrison: Now.
20:41
Jane Harrison: The the things that you can consult from your desk obviously books articles and reports of previous excavations in the area and, of course, there are so many. Jane Harrison: that are relevant to us in wall CAP and any other archaeological fieldwork published or unpublished and place names can be a really interesting part of this research.
21:02
Jane Harrison: And the locations where you find some of these things are places like the heritage environment records maintained by those local authority archaeologist. Jane Harrison: archaeologists and you can consult those online and i've given you two links here.
21:18
Jane Harrison: To to two places where you couldn't get into the Northumberland heritage environment record and then also there's the portable antiquities scheme which collects and brings together all the metal detector he finds it to report it and i've given you the link to that.
21:36
Jane Harrison: There are also the reports unlisted buildings on conservation areas and unscheduled ancient monuments, which can shed light on things, and then there are wonderful things. Jane Harrison: Like the Ordnance Survey named books and the Northumberland ones which have just been digitized and which provide antiquarian descriptions of place names which can include references to archaeology as well.
22:04
Jane Harrison: And then there are the maps which are absolutely a superb resource i'm sure you all know that by now and have been involved with looking at at historic ordnance survey maps. Jane Harrison: And the National Library of Scotland and i've been noodling there and gives free downloads of a very good quality of historic ordnance survey maps, not just for Scotland.
22:29
Jane Harrison: And then, of course, there are tight maps which you can find in local history collections and online, some of them enclosure maps and awards a State maps and plans.
22:40
Jane Harrison: Now, I just want to talk a little bit more briefly about historic maps now, this is an 1870s Ordnance Survey map of all time cracks and you can see.
22:55
Jane Harrison: The location of the excavation we were doing, which is that here, so I haven't got a nice red pointer like here and i'll have to ask him how he does that, and this is where we were we're at we're excavating and and so here. Jane Harrison: We go and when you examine sequences of historic maps, you ask yourself. Jane Harrison: what's missing, as you move between maps and what survive so are the elements from the oldest maps that are surviving right through to the most recent.
23:27
Jane Harrison: Or are there things that appear, and so you can rule out as being historic because they appear in fairly recent maps now look at two cases here there's the place up there.
23:39
Jane Harrison: Up hill from King Arthur as well and there's the place down here, and here is the 1970s map and there, you can see that up. Jane Harrison: Here we've got except I can't quite get it up here we've got Michael bank Tara Tara at 44 B, which was found in the late 19th century so wasn't on the 1870s map.
24:03
Jane Harrison: And down here we can see that the 1920s querying by the Green had mine has taken away a whole structure of the wall and here's that little stretch that we were working on at war, Tan cracks so you can get a lot of information from old maps.
24:21
Jane Harrison: Then of course there are a whole lot of other documents, including industrial records and business records institutional archives even newspapers. Jane Harrison: And aerial photographs now i'm going to just do a couple of sides talking about aerial photos and then i'm going to hand over for him to to Ian to talk about soils or the geology, in particular as a resource at this stage of the pre excavation investigations.
24:49
Jane Harrison: So crop marks are incredibly useful to archaeologists quote marks happen when there's the different growth of crops or grass over Barry ditches or pits and. Jane Harrison: or over wall foundations and there's a really nice explanation of crop marks on the historic England website. Jane Harrison: The marks only show, and these marks indicating buried archaeology and otherwise flat unremarkable field or pasture.
25:23
Jane Harrison: And they only show in certain crops and in grass in certain ideologies and at the right times of year hot summers are really good and, if you remember that reason a hot summer where suddenly there was an abundance of crop marks appearing.
25:39
Jane Harrison: ditches have a greater depth of soil, and so the crop grows better and the quote goes less well over the less deep soil of buried wolf wolf foundations. Jane Harrison: So from the air, you get patents in crops and grass created by visible differences in the way the crops are grown now i've put up on the slide here.
26:01
Jane Harrison: An example from Oxfordshire on the right are crop marks plotted on a map they've been collected over decades of taking photographs and collating that information and it's.
26:17
Jane Harrison: very complicated settlement site that's probably many phases of a little settlement. Jane Harrison: And at least partly it's Romano British and there's a track way and enclosure ditches and little pitch showing and Romano British poetry and a burial we're fans in the field. Jane Harrison: But on the other side, this is from Google earth and I totally I got that relatively recently in the last couple of years, and you can see that.
26:45
Jane Harrison: How they match, and indeed how there are more features showing in that Google earth image than on the collected and that the sort of collated crop marks so Google Earth is interesting, you can find crop marks in Google Earth.
27:02
Jane Harrison: aerial photographs and whether they're from straight overhead or whether they're from an angle, also a very good for capturing. Jane Harrison: And not that buried archaeology that is showing in crop marks, but in archaeology that surviving and as earthworks and he can see the earthworks captured in an aerial photograph of a deserted medieval village it's a smartphone in Northumberland.
27:27
Jane Harrison: And you can see, the region pharaoh of the fields of the village and rant here, you can see the earthworks of the street and of the various. Jane Harrison: buildings and gardens of the village and, interestingly, if you look at the 1990s map and i've kind of them twisted it around so it's on the same orientation looking West as the aerial photograph.
27:51
Jane Harrison: Absolutely nothing on the map at all, and then on the right, you can see a very famous 1920s photograph of you, having and you can see the crop marks there.
28:05
Jane Harrison: And that's a reconstruction of one of the ideas about how you ever in locked and you can see the crop marks of the big enclosure at you ever in here the ditches and here are the outlines of the various phases of the great pause that you everything.
28:22
Jane Harrison: OK, so now i'm going to stop talking for a while and i'm going to hand over to him to talk about geology and the run into thinking about an excavation thanks Ian.
28:35
ian: Alright, thanks, a lot Jane i'm are you happy to just push the slides on for me as well. Jane Harrison: Just tell me when. ian: we're doing great thanks, very much indeed, good evening everybody, and I just wanted to very quickly here before I talk about some of the things that you can do in terms of preparing to do digs.
28:54
ian: is to actually talk through some of the relationship between geology and archaeology just to give a sense of the some of the reasons why. ian: As an archaeologist geology might be something which is of interest to you so i've given for headline ideas here and they may well be more of them. ian: But I just wanted to give you a starter for 10 and some of this will talk more about in the next session we get to actually talk about actually doing the digging and how you explore things there.
29:24
ian: But this is just a very quick summary just to get the thoughts going on this particular subject.
29:32
ian: So the first and most obvious thing is that the the physical artifacts that you actually find with an archaeological dig very often have a geological source. ian: And most obvious example of that is when the hadrian's wall whether the physical object is built, out of stone, which is a geological material and but also. ian: For example, the.
29:52
ian: example the Jane gave in in the deacon in suburbia locks and where there are lots of kills and lots of pottery one of the reasons why that's The case is because you have Oxford play, which is a really good source material for making POPs out of.
30:07
ian: And so, by simply by understanding the the geology of an area it will start to give you some ideas about what some of the reasons are why some of the archaeological material is actually there, I will just local or whether it's been important for example.
30:23
ian: The second thing is about the landscape that.
30:28
ian: There will be a reason.
30:30
ian: Probably why a particular archaeological construction is there.
30:37
ian: that's that there'll be a reason why a building has been built in a particular place there'll be a reason why artifacts have been hidden in a particular place and the landscape gives the but the context within which you can actually understand that. ian: and also the landscape and the geology have a direct impact on the soils, so the soil types are directly affected by the geology hand by.
31:01
ian: implication also the biodiversity is affected by it as well, so there's you want to understand the types of seeds and plants and. ian: animals that have been living in the area, going back and looking at the challenges that sits underneath that is immensely helpful in terms of actually understanding that.
31:20
ian: The next point is about dictionary which we'll talk more about in the next session. ian: But just to point out that the way in which the strategic really develops even that an archaeological dig has got two parts to it, one is sorts of material will find within that particular fee will be geologically derived. ian: And so, understanding, where the materials come from will help you understand that, strictly goofy but also that geological processes, as well as man made.
31:47
ian: Intervention will be responsible for creating some of that strategic rfi and again by understanding the geology and those geological processes that helps to understand and i'm pick the way in which is terrific up within the biggest developed.
32:02
ian: And finally, there are some very rare occasions where the an archaeological dig can actually. ian: uncover something announced something and was geologists wants to know about and I have in my mind, a specific example of that from. ian: Some work I did on lindisfarne which i'm not going to go into now, because of time constraints, but if anybody wants to know about that have been very happy to talk to him about that thanks.
32:25
ian: Everyone next slide please.
32:29
ian: So what I want you to do now is having giving you some of the ideas about.
32:34
ian: What sorts of reasons that are to think about for geology. ian: And it's actually to give you some pointers to the sorts of things which is worthwhile going and looking at as a way of being able to prepare for a dig. ian: And the first and most obvious of those is geological maps and the big s provides a fantastic online.
32:54
ian: geological map which makes it very easy to actually explore explore the geology and there are really two parts to that and the big s allows you to unpick that very easily just using simple buttons on the application, the first here is an example of a. ian: Solid geology which underpins. ian: The area around green had a small town crags and there are various important things that you can see from this one is.
33:17
ian: The great purple splodges the wind still going through it, which relates directly to the landscape, on which that the wall is actually built The other thing which you can see, in here, you can see the way that the.
33:29
ian: lines of Georgia, get disrupted by fault lines, and these are quite important to understand because they give some understanding of the structure of the way in which the area of riddick might be affected.
33:43
ian: me, in fact, the force which you saw on James were both of James maps and show the whole town crags is something which relates directly to to and from the. ian: Top right hand side you'll see that the wind silver's got which which comes down with that directly underneath that foster that relationship between what you're seeing on the ground and hard to.
34:07
ian: Cover next slide please Jen.
34:11
ian: The other thing to look at is the what's called the drift geology, and this is a combination of material which is a draped over the surface of the landscape by ice ice the ice ages and so as the ice disappears it bleeds behind it, a bunch of glycine garbage basically and also.
34:32
ian: That after that glycine material and the time that facing materials with throwing that they'll be reworking your material by rivers. ian: And what the drift maps tell you is what the sort of material that you're actually likely to be digging through is and that.
34:50
ian: Again, will obviously have a fairly significant impact on the way in which you can carry out the deck i'm in terms of you going to be going to sand or boulder clay and walk some other sort of material and it's addressing that which will give you a lot of information about that.
35:06
ian: What do we got next next slide please.
35:09
ian: And the other thing. ian: That I would highly recommend as a way of.
35:13
ian: Of of getting to understand the geology is going and looking at the rocks and because it's only by looking at them and touching that you really start to understand. ian: The types of artifacts you're going to be fined and the material you're going to be digging through so.
35:27
ian: just put up a couple of examples so here's a limestone for more than limestone cars and on hadrian's wall jobs these parts of the material which is used for the line to to bound it and the wind still hear it a lot of town craig's and the next one.
35:43
ian: Which is sandstone and.
35:46
ian: So just going out and looking at these and understanding them and this particular last example is one from some these such a bit of be sandstone so so those of you that came on the. ian: On Stuart jones's talk will know that that would be Stan Stan is very distinct from the penrith sandstone and that by looking at touching it helps you understand that and one final slide, this is a salt.
36:10
ian: That geological material is a resource which is used not only for.
36:18
ian: physically creating the artifacts but also as part of the way in which you can create those artifacts so next slide, which is a band of coal and which is a material which is used as part of a process in order to, for example, to do on working or brass making.
36:38
ian: So there we go a couple of pointers for what geology is about, and some of the things which are worthwhile looking at. ian: There are also other geological tax which you can use so there's usually memoirs and other guys to the geology the area. ian: And, but I would recommend the best way to if you if you need some help in understanding the geology is to talk to a friend of a geologist and i'm happy to offer myself as that person so.
37:03
Jane Harrison: Thanks and thanks ever so much yet in friendly geologists by you, so if you can have your friend a geologist out on site, while you're excavating that's even better.
37:12
Jane Harrison: Great thanks a lot him and he.
37:15
ian: Just decided that that I will be out on site I hoping that if you've got questions about the geology we can do that, then. Jane Harrison: Right brilliant thanks in OK so we've talked about those. ian: desk based and. Jane Harrison: Researchers that you can do. Jane Harrison: Before excavation let's think a little bit now about other sorts of fieldwork what is obviously often called a non intrusive so non destructive fieldwork, most of which doesn't break the ground and and.
37:42
Jane Harrison: When you get it it's then when you need to get out you just get familiar with your landscape need to walk over new to look at views you need to start to really understand it.
37:54
Jane Harrison: And this is also a stage where you can do what's called a topographical survey that's where you record those humps and bumps. Jane Harrison: That a cover surviving archaeology that hasn't been leveled and laid flat and needs to be picked up in other ways. Jane Harrison: You can do field walking where you go to mock systematically on plowed field and gather the artifacts and poetry that you find.
38:16
Jane Harrison: And that can be really useful because, in conjunction with geophysics which doesn't help you directly date things it can help you suggest the dates that some of those things that you're picking up in geophysics might be. Jane Harrison: You can do a metal detector survey again walking systematically around the field and picking up any artifacts and then of course geophysics of many kinds and you've got alex's talk online, which introduces you and talks about.
38:43
Jane Harrison: geophysics and a lot more detail the kind of work horse of pre excavation and non invasive non intrusive survey is grade geometry or magnetometer.
38:55
Jane Harrison: And this is the the geophysics shown in both of these slides, which is particularly good at picking up filled ditches pits.
39:06
Jane Harrison: And picking up burnt features and very organic features and resist diversity, which is the other main geophysics is particularly good that works with electricity rather than magnetism which magnetometer he does. Jane Harrison: It works with how well materials conduct electricity and that's much better at picking up rubble or compacted surfaces or stone.
39:29
Jane Harrison: And now, on the slot on the slide you can see some magnetometer from heaven on the wall thanks Alex for that, and this is over the volume and this is part of. Jane Harrison: One of the wall CAP investigations which is asking questions about how well the volume is surviving in.
39:47
Jane Harrison: pasture as opposed to plow fields, so these two are stretches of the fallen in a plowed field, and this is a stretching pasture and you can see from the responses he even even without going into detail, but it's cleared teams to be surviving much better in the pasture field.
40:07
Jane Harrison: And this is the rest of stupidity, so the one that picks up compacted material much better or stone or rubble from exactly the same areas, and you can see it's picking up slightly different features, but that.
40:22
Jane Harrison: But that it correlates quite well with the magnetometer and sometimes they will reflect quite Similarly, the two processes, sometimes they will pick up quite different things and and then you can see, this geophysics plot from Oxfordshire again, which is across a whole big field.
40:42
Jane Harrison: And is picking up, you can see.
40:46
Jane Harrison: Long ditches, some of which are very full of either very organic or burn material and large and some little rings ditches and that they're overlapping and quite complicated so it's clearly quite. Jane Harrison: A well used site, but we can't directly date it, although we can make some guesses and we can't and from that tease out which bits were in use, at the same time.
41:16
Jane Harrison: So there are other sorts of investigations ahead of exploration which aren't strictly non invasive but a very small and very targeted, you can do boreholes and to look at deposits and what they're like you can do those tiny little test spits they talked about.
41:33
Jane Harrison: which give you dating material can tell you about the condition of archaeology and the depth of the plow soil or the topsoil. Jane Harrison: And usually you stop if you find any undisturbed archaeological layers and also little evaluation trenches which is slightly bigger, but with the same sorts of intentions to find out. Jane Harrison: What the survival is like and what the depth of the archaeology is and sometimes they help us to read the geophysics better.
42:03
Jane Harrison: Okay, what i'm going to do for the last 10 minutes or so is finally to talk about locating trenches but to use an example.
42:14
Jane Harrison: Of all the non invest invest evasive investigations that we did on one site that's part of a wider community landscape pop project in Oxfordshire. Jane Harrison: And it's an area that has seen virtually no archaeological research at all, and that is because of its geology and because of its land use and it's produced no crop marks because of that geology and land use, so the that helpful and.
42:44
Jane Harrison: Finding of sites using aerial photographs hasn't worked at all for this area, because the geology and the land use hadn't allowed it, you can see, there are powered fields and pastures, but but. Jane Harrison: The crop marks are not working, because of the geology underneath it and I can explain that more if anyone's interested in that and. Jane Harrison: And so the site i'm going to talk about is is part of the project focused on a deserted manner site called vessels Lee.
43:12
Jane Harrison: And all that survives of it now is a little 12th century church. Jane Harrison: That was associated with the manor and the rest of it is all in this private parkland and you can see some of our geophysics plots there. Jane Harrison: Of the wider landscape project, as well as the ones that are related directly to that site.
43:29
Jane Harrison: Nothing is known about the early history of the medieval version of the manor it was rebuilt in the seventh in the 16th 17th 18th centuries before it was abandoned in the 18th century after a fire. Jane Harrison: And we know absolutely nothing about the related village, but we do know that it was almost certainly one of the most important villages in the area, so.
43:55
Jane Harrison: This is just an interesting snippet of the documentary evidence, this is the tireless john Leah Leah Leyland who went throughout England describing and what he found during the 16th century and he described. Jane Harrison: breathlessly than our vanished village as being three miles from the ferry at hinksey. Jane Harrison: In very fair pastures and woods and there's little clue for us and woods is woods, a very important in this area it's still fame to the quality of its would.
44:24
Jane Harrison: And he says that the place and we're not quite sure from his description, if you means the village or just the manor house is all of stone and stands at the West end of the parish church so that's the little surviving church.
44:38
Jane Harrison: And here is a map and 18th century map of restlessly. Jane Harrison: And that is the little church still survives, and this is the area that you saw on the modern map with no religion at all, but it's just picking a whole selection of buildings now.
44:56
Jane Harrison: This map we can't rely on it for absolute accuracy and the buildings tend to tend to be sort of just depictions of there being some buildings there, rather than accurate representations, but nonetheless it shows a lot more activity than there is now.
45:12
Jane Harrison: And then here you've got a State map and it's a beautifully drawn a 3D map from a little bit earlier than the previous one of the later manner. Jane Harrison: And here's that lovely little church and you'll see a photo of it in a moment you'll see how unchanged, it is here's a trackway into the site. Jane Harrison: And here's the depiction of the main Manor house and and the question is was the earlier medieval one on exactly the same side or not.
45:44
Jane Harrison: And here are the farm buildings behind and the Little Red squares show where we dug little test spits just to have a little look see to see what was surviving and here's one of our local evaluation trenches.
45:57
Jane Harrison: Now we did lots of other things, and here now i'm focusing in on the area here's the church here in this area and underneath this Gray, is the. Jane Harrison: geophysics the magnetometer tree, and you can see that it's really not nearly as exciting looking as the one is what some of the ones you've seen. Jane Harrison: All this black and white suggests a lot of rubble That in itself is interesting, because that is the core of the manor house site.
46:30
Jane Harrison: And overlaid on it bit difficult to see but you'll see it again on another slide is a topographical survey, so this was done by hand and with volunteers on a on a. Jane Harrison: Drawing and to scale all the earthworks and it's depicting a rich here and that's in the location of one of the walls of the entrance way of the later Manor house.
46:53
Jane Harrison: And then, all you can see that there's a big dip here, which is again just west of the church and around the area of the main Manor house. Jane Harrison: And this is racist devotee over that track way. Jane Harrison: which shows very high responses and suggests stone or rubble that doesn't conduct electricity very well and we dug a little test spit and.
47:16
Jane Harrison: you'd be interested in what we found was the trackway was located on one of the little caps of bedrock that float amidst the sand and clay, in this very complex geology. Jane Harrison: And they were clearly aware of that and put the track way to make use of the geological formation, as the bed of their road and this little test pit here and which is in the area of the manor house found of the farm building sorry found a.
47:48
Jane Harrison: What just looks like the foundations of a farmyard and found quite a lot of 16th 17th 18th century poetry, but interesting also medieval poetry so we're getting hints of there being that earlier manner underneath.
48:03
Jane Harrison: And here's that same view here's the Church, and this is the rest of it for that area, so you can see that topographical survey the humps and bumps more clearly. Jane Harrison: And the locations of there's Oracle evaluation trench and here's a third test pit which was in the Center of the manor complex, and here we found another and foundation for probably an internal floor and or opt out war.
48:28
Jane Harrison: And here we did again get some 16th 17th 18th century party, but an awful lot of medieval poetry from the disturbed area of the rob doubt war so again really helpful to know how things are surviving but that also that there is medieval activity in the area. Jane Harrison: And they're literally evaluation trench is across where we think there was a courtyard wall and this shows.
48:52
Jane Harrison: That under excavation here's the lovely little church looking very much like that earlier plan and here is the wall that we discovered whoops sorry. Jane Harrison: The wall, we discovered and a 3D representation of it and the interesting thing was that we stopped when we got to understood levels, but it was clear that something very different was going on.
49:12
Jane Harrison: That side of the wall and, on this side and what was on the nearest side look like it was from inside a building a building they didn't show on any of our documentary and researchers.
49:23
Jane Harrison: Okay, so that's all the things sort of taster of the things that you can do in the run up to doing an excavation and the sorts of. Jane Harrison: it's a huge wealth of material that you can can go out and look for I mean sometimes you do an excavation that doesn't have that kind of material that you can use and you're relying on only one or two of those fans of evidence, but. Jane Harrison: And, but there's also the practicalities that have to happen.
49:51
Jane Harrison: And you've finished your research and your non invasive surveys and investigations you've you've honed and your project design with your questions you've targeted your site and you've thought about where you're going to put your trenches. Jane Harrison: And the other things you have to do with think seriously about the money, you have the people you have on the time you have.
50:10
Jane Harrison: Although we all know that you can do everything possible to try and plan ahead, but the below ground archaeology can always throw you a surprise. Jane Harrison: and things are often not detected by geophysics I worked on a large room inside where a huge late room and building absolutely didn't show up in.
50:28
Jane Harrison: The geophysics and again that was because of geology because there was so much hard geology very close to the surface and you can come across extraordinary preservation, think about vin de Landa there can be extraordinary finds that whole things up human burials.
50:45
Jane Harrison: So you can't plan ahead for everything that you do need to get your permissions to be there, your access has got to be arranged and you've got to get. Jane Harrison: permission, for example, to work on a scheduled monument site and you've got to do risk assessments and health and safety you've got to check that there aren't any services and sometimes you have to baton you surveys or other surveys related to the foreigner flora and fauna.
51:11
Jane Harrison: And you've got to think about whether you need to do any clown ground clearance with you need to make sure there aren't cattle or sheep are going to be too curious about what you're doing. Jane Harrison: And you have to acquire all the equipment, including all the paperwork and you have to think about whether you need any infrastructure, do you need shelter toilets storage fencing.
51:33
Jane Harrison: And you've got to think about the weather and you you'll know from what happened at corbridge and. Jane Harrison: I know from several of the sites i've worked on the weather, can also be something that throws you a really curveball.
51:46
Jane Harrison: So you can see, this is the nunnery site that had talked a little bit about this is what it looked like before we started and that's just trying to work out where our trenches might roughly be this is bringing in the infrastructure and that's the same site after excavation.
52:03
Jane Harrison: Okay, so now i'm just going to talk for five minutes about how we decide exactly where to put our trenches because if you look at the scale, this is a large field and we can't dig huge trenches, particularly if it's a research or a Community excavation.
52:21
Jane Harrison: And so you've got to think about what you exactly where you're going to place them. Jane Harrison: And you'll be guided by all information that you've collected all the research you've done, especially for crop marks we had absolutely nothing for this field, because of the area was in. Jane Harrison: here's the geophysics that's really helpful and although it doesn't pick up absolutely everything we had done field walking but had picked up.
52:46
Jane Harrison: relatively little some very scrappy little bits of Roman posse that suggested the poetry that went on a field when there was maturing rather than being in indicating there was a settlement really nearby and we had done.
53:01
Jane Harrison: A metal sector survey and found again almost nothing and that probably because it had been done before. Jane Harrison: And what we did do was to was a little test spit up here in the field margin, where we weren't. Jane Harrison: going to excavate and that interestingly, produced a little a little ditch with iron age poetry in it and some early Anglo Saxon poetry, so that was really quite interesting.
53:28
Jane Harrison: So, then, we want to choose the location, that we think will help us best and best answer the questions we've got for the site about its date. Jane Harrison: about what sort of site, it is the length of time it's been occupied how many changes that were in the way in which that the settlement was organized and.
53:49
Jane Harrison: Not all that you know, not all of the features shown in that geophysics will have been around at the same time, and so all those sorts of questions that guide us where we might put them.
54:00
Jane Harrison: Areas that ELISE disturbed trees, sometimes not in this case it's a field but certainly on other sites trees or other things can be in the way.
54:10
Jane Harrison: And here, and this area is sort of blanked out because the people who live nearby have a big bonfire of the fifth of November and the remains the bumper always go on the field in this place and so it's it's blanked out that the.
54:27
Jane Harrison: Anything that geophysics could pick up at the ditches or pits that were underneath that. Jane Harrison: But, most importantly, we try and put our changes in the areas where we can detect where we can explore significant relationships between features and that we can see in the geophysics or that we suspect might be there and explore in the important parts of the site.
54:50
Jane Harrison: Okay, so here's where we decided to put the ones on this site and and you can see, the one up here is because that's a rather unusual response these dark features here.
55:05
Jane Harrison: aren't buried metal and probably modern stuff like this, we can see the brat black with a bright white grounded, which is probably a bit of plow or a tin can or something they have no white surrounding them and so they're likely to be burned or particularly highly organic material.
55:26
Jane Harrison: And in fact it turned out that that one of those was a pit kill and I need to pick kill for making pottery.
55:37
Jane Harrison: And the one down here is looking at the relationship between these these ditches you straight ditches and this circular one. Jane Harrison: And what we found there was that this is the gully surrounding a nine eight ranch house, and these are later ditches also on age, which show immediately. Jane Harrison: That the roundhouse was there and was used, and it must have been flattened before those ditches with Doug to enclose some later fields.
56:05
Jane Harrison: And we put one here because we wanted to investigate the relationship between this very exciting big ditch and these elements of ditches here. Jane Harrison: And this default thing here we're trying to sample different parts different aspects of the geophysics.
56:19
Jane Harrison: And that turned out to be a huge enclosure ditch full of metal working and rubbish so that's getting that strong response, and these are our ditches that help enclosed parts of the sacrament for stock and things like that, and the one down down here this one.
56:37
Jane Harrison: Here it's looking at the relationship between this stitch explored up here and this great one here, and this funny little circle pits and it turned out to be a really complicated combination of.
56:52
Jane Harrison: The the galleys from ranch houses that have been outside the enclosure before this ditch was built and various other ditches and so you from the geophysics you can't tell a complexity, but we were trying to pick locations where we might try and untangle it.
57:09
Jane Harrison: And here is the wall.
57:12
Jane Harrison: And here very different, this is the war castle. Jane Harrison: And the research questions are asking about the character and survival of the war remains in the fields west of the castle so quite specific direct research questions. Jane Harrison: and looking for evidence for the phases of destruction of the wall into the building if there will Castle and to try and get and also to try and get soil samples.
57:37
Jane Harrison: And they decisions here about this is the wall here about putting the trenches in the best places to explore the history of the wall and and whether the new management land management it's under is working and where, would you put them it's one thing we can discuss next week.
57:57
Jane Harrison: It is a bit of a dark heart deciding where to put a trench because, as I say, you'll never know everything, what would be the point of excavating if we did. Jane Harrison: And, and what would you do with a site like this, this is one of the things that popped up in that really dry hot summer, a huge historic sites.
58:16
Jane Harrison: In Oxfordshire and where do you begin with something like this okay so i'm just about finished and all i'm seeing now is well how does all this help you when you're out there digging. Jane Harrison: I think that digging is always thoughtful as you're digging always thinking about how is it that this has ended up like this, what did people in the past, do and what's happened to the site, since they did that.
58:40
Jane Harrison: For me, to find it in this state and all those factors that are involved in thinking about the research, the. Jane Harrison: Investigations ahead of and the thinking about where you put your trenches or help you're digging to be focused and. Jane Harrison: thoughtful and therefore we're getting towards that absolute best digging that we want to do to be as respectful as possible to the sites we're working on Okay, thank you i'll stop sharing.
Here to help you learn
Sign in to keep a private conversation with your course tutor.
Ask me anything about the material…
Sign in to chat