I’ve now been with Allen Archaeology for 8 years and 7 months, and have managed in that time to drag myself kicking and screaming up to the exalted heights of Senior Project Officer (mostly in charge of geophysics, but also other stuff too). I can normally be found in one of two places, either chained to my desk writing up reports or helping other people with GIS issues (along with Charlotte and Mia), or out in the world on geophysics missions (or sometimes, very rarely, actually digging). I’ve found the higher up the totem pole I get, the more time I have to spend in the office. This is all well and good when it rains, or during the winter, but can occasionally be a little disheartening when the weather is nice and I’m hearing about exciting sites others are currently on.
The location for such adventures can be as far afield as Suffolk, Staffordshire, Yorkshire or even into Wales. Have magnetometer can travel.
So with a trusty minion in tow, (occasionally we require more than one team for larger jobs – I try to not let the power get to my head) I head out to the required area. I’ve worked on a large number of geophysical projects over the last 7 or 8 years, from tiny areas of less than a hectare to mammoth cable route jobs- surveying a 60m wide area for a length of 50 or 60km. Unsurprisingly during that period I’ve encountered all possible weather conditions, from blizzards to torrential rain, and thick fog to baking hot summer days. The one constant being a steady 1.5 or 1.6m/s walk across a field.
The first job when we arrive on site is to set out the grids. Prior to the job commencing, I make sure I’ve set out grids (20m or 30m) on the computer, and we use the GPS to mark out the corner of each grid with bamboo canes- no metal allowed as it affects the readings of the magnetometer. My trusted minion will then start pegging out, we have 20cm long red pegs to go in between the bamboo canes suitably spaced to provide equal transects for me to walk along. In the meantime I’m attempting to balance the magnetometer before I can start surveying.
Balancing the magnetometer is somewhat of an art rather than a science. I need to find a magnetically quiet spot within the field to run the set-up balance program- this zeros the machine’s two probes in the earth’s magnetic field and with each other. However in order to properly locate a magnetically quiet area I need a balanced machine, and to accurately balance the machine I need a magnetically quiet area….
Once a suitable location has been found (in some cases we’ve had to take the machine away from the site to a different location, balance it, and then drive back very carefully to the site taking care not to bump the machine on the way), I run through the set-up program on the machine. This sort of looks like I’m doing a very slow square dance, involving spinning around and rotating the machine at set intervals. This process can take some time, and often I’ll run the set-up program a number of times before I’m happy that the machine is properly balanced, not complaining, and ready to start.
The rest of my time is spent walking up and down the field in either 20 or 30m transects, counting up to 21 or 31 respectively, and trying to keep my pace constant, whilst trying not to trip over and vegetation or crops that happen to get in my way, or fall down any rabbit holes. Keeping a constant pace is very important as it means that any anomalies that are revealed by the survey are displayed in the correct location on the results. We almost always use a zig-zag pattern for surveying, and if I don’t keep my pace constant it can be very clear in the results when linear features end up looking distinctly broken up and not wonderfully linear in nature. Tricky situations involve surveying up and down slopes, or through slightly thicker than optimum vegetation.
Finally, when the area has been surveyed (or the machine has filled up, it holds about 3 hectares of survey data before it needs downloading and deleting), I get to hook the magnetometer up to a laptop, download the data and get my first look at the survey. This is the best part of the day, as I’m seeing results which can reveal archaeological features that can be up to several thousand years old. Or the exact locations of modern services like gas or water pipes- they tend to show up very well.
Weary but buoyed up by happy exercise endorphins I head back to the office to show off all the exciting things I’ve found. If there’s still more to survey then I can look forward to another day walking up and down fields, if the job is complete it’s back to being chained to my desk to write the report up.
Occasionally I get to interact with local wildlife or people, mostly to explain that what I’m doing is a bit like some of the stuff they’ve seen in Time Team.
