Open Area Excavation in Archaeology

The open-area excavation method is one of the four main excavation types in archaeology and is applied to excavate large areas without baulks. As you are aware, archaeology is the study of past human culture, behaviour, and cognition through material remains left from the past. So, excavation is the way of acquiring those material remains left from the past. When it comes to excavation, there are four types according to the way of executing the digging within the site parameter, namely, grid method, open area, trench, and quadrant. This article is to study open-area excavation in archaeology.

Introduction to the Open Area Excavation Method in Archaeology

The open area method is one of the major excavation methods in archaeology, and it is ideal for large-area excavation. In this method, we excavate the entire area of the site that we plan to dig up during the excavation project. We do it without leaving baulks or any sort of sections or partitions in the excavation area. Simply put, we excavate the entire area as if it were one big pit. Well, there should be only one pit in this open-area excavation method.

The preparation for the excavation is similar to the other three types of excavations. Initially, we lay the grid on the site and choose which grid boxes to excavate. But the excavation is not always restricted to the grid. So, the open-area excavation still uses a grid, but there are no baulks in between units in the grid. In simple words, there is no visible grid pattern in open-area excavation as seen in the grid method of excavation.

In this method, it is free to lay out sections of the excavation plan as necessary. And also, the excavation does not necessarily have to be conducted at once in the whole area. Archaeologists can execute it gradually according to the plan or situational needs in any direction and in any shape required. Archaeologists developed this method, eradicating the disadvantages of the grid method with its key feature of baulks.

History and Origin of Open Area Excavation Method in Archaeology

Archaeologists developed open-area excavation methods in the first half of the 20th century. They developed this method to address the issues of grid-method excavation, which Mortimer Wheeler introduced in the 1930s and Kathleen Kenyon refined in the 1950s. Archaeologists conducted the first open-area excavations in the alluvial lands of the Netherlands, Germany, and Scandinavia.

Characteristics of Open Area Excavation Method in Archaeology

The open-area excavation method in archaeology has a few unique characteristics that make it different from the other three types of archaeological excavation. Here are three main characteristics that we can see practically in this method. The other characteristics are discussed in the section under the advantages of this method.

1. No Baulks

The open-area excavation method does not consist of any baulks. Baulks are the mass of soil that is left between the units of the grid during an excavation. For instance, the grid method of excavation consists of baulks. These baulks are typically 50 centimetres wide and separate each unit in the grid, making the excavation a group of evenly distributed pits. But in the open area method, there are no baulks.

2. Single Pit

The open-area excavation does consist of a single excavation pit. As described above, since there are no baulks involved, there is no partition or separation here. All the units in the grid that are chosen to be excavated are excavated into one large excavation pit.

3. No Limits

Since there are no baulks and the entire excavation at the site is just a single pit, there are no limits to this method. That means the units in the grid do not affect the progress of the excavation. The markings on the grid lines serve the purpose of recording, but they do not restrict the direction or shape of the excavation. This becomes a unique feature because, in the grid excavation method, the grid lines limit the direction and the shape of the excavation. And if the situation makes it best to excavate further, the archaeologist may have to move into the next unit in the grid. But with the open method, archaeologists can continue excavating without limiting or stopping at boundaries.

Advantages of Open Area Excavation Method in Archaeology

The open-area excavation method brings us several important advantages. Let’s look into them.

1. Provides a clear view of the entire excavation plain

The open-area excavation method provides a clear view of the entire area of the overall plain of excavation. But in grid-method excavation, we cannot see the entire plain of the excavation at once, making our observations harder. But the open area excavation method provides us with a clear view of the entire excavation as it does not contain baulks, any sort of separations, or obstructions in the middle.

2. Allows us to examine the evidence found throughout the excavation as a series of horizontal plains

Without baulks or any sort of obstruction in the middle, the open-area excavation method provides us with a single excavation pit. The digging in the area of excavations is vertical. That means we dig from top to bottom along the vertical axis. So, we dig up a series of horizontal layers of soil throughout the excavation. In grid-method excavation, we do the same.

However, the difference here is that in the grid method of excavation, even though the soil layers we dig up are well recorded, we cannot get a complete series of horizontal plains. We have to match each layer with each unit to get one horizontal plain. Even there, we miss out on a considerable amount of area from the horizontal plain as there are baulks in between units. But, with the open-area excavation method, we can have a series of horizontal plains. So, we can examine all the evidence we found in the excavation as a series of horizontal plains.

3. Allows us to examine the evidence without any obstructions

Since the open area excavation method does not contain baulks or any sort of division partitions in the excavation pit, it allows us to examine the evidence found without any obstructions, such as sections or baulks. We cannot guarantee that we will find every important piece of evidence within the perimeter of units not submerged in the baulks. For instance, in the grid method with bricks, examining the evidence can be much harder and even ineffective. But the open-area excavation without any obstructions, such as baulks, allows us to examine the evidence found without any obstructions.

4. Allows us to examine the connection between the evidence found anywhere in the excavation

The grid method of excavation with its baulks fails to fascinate us enough to physically examine the connection between two points in the same excavation. If there are two materials remaining in two units in the grid plan, the grid method obstructs them with baulks. But the open area method provides the space for archaeologists to physically examine the two points or artefacts in real time. That is because it does not include baulks.

5. Ideal for context-method excavation and recording

In archaeology, there are several methods of excavating and removing the soil. Stratigraphy context method, context method, metric, or planum method are only a few of them. Each of these methods comes with a unique way of excavating and recording.

In archaeological excavation, everything we find is found in context. A context can be a stone tool, a pot, a spot with pottery pieces, a spot with artefacts, or even a spot with slightly different soil.

In the context method, as the excavation progresses, archaeologists identify these contexts. They number them and plan how to excavate them, focusing on them separately. Of course, they consider the surrounding context. Here they plan how to excavate each context, as each context is always unique and needs special care. For example, excavating a stonetool collection and a bead collection can be different. If the archaeologists excavate each of the contexts separately, they might be able to reveal if the beads were from a necklace or just a container or bag of beads. So, the context method means planning, excavating, and recording each context individually within the main excavation.

One mighty example comes from the Ibbankatuwa Megalithic Burial Site, Sri Lanka. The archaeologists have recovered a bunch of carnelian beads from that burial site, revealing the structure of the necklace as they carefully excavated according to the context without excavating a bead by bead. (see images of bead necklace from Ibbankatuwa, Sri Lanka)

So, if there were baulks, archaeologists would have to stop at grid lines, no matter how important the context in which they were digging. Therefore, the open area method of excavation is the ideal method for conducting the context method of excavation and recording.

6. Different parts can be dug in several seasons, respectively

As you already know, in the open area method, grid lines or baulks do not limit the excavation. Therefore, there is no rule that the excavation pit needs to be like a perfect square hole down to the bedrock. It is true that archaeological excavations usually go for the bedrock. But, with fair reasons, archaeologists can decide to stop the excavation for the season or session. Since this method allows us to excavate in any direction and in any shape, the excavation can be paused and continued.

Also, the excavated part is always completed, unlike in the grid method of excavation. Therefore, archaeologists can excavate different parts of the excavation area in several seasons without issue.

7. Relationships between features can be identified

As it leaves no baulks or sections, the entire excavation pit is open as a series of horizontal plains. That allows us to study the relationship between each context of the excavation on site as well as on the record.

8. Provides a more vivid representation of large-scale material remains

The open-area excavation provides us with an open view of the entire excavation site. Hence, it provides a more clear view of large-scale archaeological data such as settlements, structures, farms, etc.

Disadvantages of Open Area Excavation Method in Archaeology

While the application of open-area excavation has its advantages, it also has disadvantages. Archaeologists apply this method when no other method would work well. That means this method comes in handy when needed. But this also has some downsides. So, here are the disadvantages, issues, or problems with the open-area excavation method.

1. destructive in nature

When compared to other excavation methods, open-area excavation is more destructive. As I have explained in a previous article, an excavation is always a destruction in archaeology. By excavating, we destroy the deposits of material data that lasted for centuries, if not millions of years. And it is irreversible. So, obviously, open-area excavation destroys the entire archaeological deposit forever.

2. Expensive

As you are aware, excavating a large area entirely costs a huge amount of money. Relatively, other types of excavation can be cheaper for two reasons. One is that those methods do not excavate the entire area. The second is that it is harder to manage an excavation without baulks. Therefore, the open-area excavation method often faces financial constraints.

3. Time and energy-consuming

Just as in the financial aspect, open-area excavation requires a lot of time and energy. Sections and baulks facilitate a passageway for labourers to discharge the dug-up material. The area of the excavation is relatively large and leaves no sections. Therefore, it requires more time and energy to excavate a huge amount of deposit and to record with accuracy while handling a lot of tools and a crew.

4. It may take several seasons

As you know, the area of the excavation usually tends to be larger with this method. Hence, in areas where seasonal flooding or rainfall happens, obstructions such as rising groundwater levels can happen. And that may force us to hold the excavation temporarily, causing the excavation to take several seasons to complete.

5. Recording consumes more time and effort

Open-area excavations allow archaeologists to excavate relatively freely. Without leaving baulks and without having to maintain specific limits or shapes in excavation, an open-area excavation can be irregular and large. Therefore, there are no reference points in the excavation area. No baulks, no unit boundaries, no grid lines. That makes it harder for the recording. And as the recording of archaeological excavation has to be precise, it consumes more time and effort with this method.

6. Incapable of re-checking the accuracy of the recording

When it comes to recording in archaeological excavation, we use one or a few anchor points, which we take as reference points for measurements. It is best that we have more than one anchor point. For instance, in the grid method of excavation, we have three anchor points for any point in the space inside the excavation pit. Those are the so-called xyz in the grid method. But with the open-area excavation method, there are no vertical plains of the excavation for us to take measurements from. So, we cannot reassure the accuracy of our recording.

7. Unearthed levels of horizontal plain are subjected to destruction

As the open-area excavation method does not have any baulk, people have to walk on the horizontal plain of the excavation area. Walking on the unearthed surface and carrying weights of dug-up soil can potentially damage the horizontal plain of the excavation. If there is any sensitive material remaining hidden beneath, that can end up being destroyed during the excavation process, which is not a good thing to happen.

8. Hard to protect the entire horizontal plain of the excavation

As the excavation plain is horizontally large and has no sections, protecting it from sudden rains with covers is merely possible. Without baulks in between units, building a roofing structure can be quite challenging, if not costly. And also, since the area is larger, sudden actions may not be able to be taken before the dam is done.

Summary

In summary, open-area excavation is one of the major excavation types in archaeology. In archaeology, excavation types come from excavation methods. So, we often refer to the open-area type of excavation as the open-area excavation method. However, archaeologists developed this method to address the issues with the wheeler-box grid method. In this method, the main feature that the grid method had was removed. Instead, the excavation was carried out without baulks or any sort of section. This resulted in both positive and negative outcomes.

Allowing us to have a clear and full view of the excavation site, providing us with a series of complete horizontal plains, allotting us the ability to determine the connection between any given points in the excavation area, and letting us fully uncover contexts without obstructions are a few of the advantages of this method. Having issues with financial, time, and labour costs, as well as not being easy for recording and site management, make up the disadvantages of this method. However, we apply this method to conduct both vertical and horizontal excavations, depending on the study.