Done

Anyone new to this blog or geophysics in archaeology is recommended to read the material on the “Geophysical survey in archaeology” page.

I think Mike Smith would argue that he is “done” in more ways than one!  I feel that a suitably sonorous 1950s newscaster voice ought to be saying “at 1pm this afternoon, members of…”  The reason?  Because at 1pm this afternoon the GPR survey finally surveyed the last part of the theatre field (Figure 1).

Figure 1: Mike Smith crosses the finish line.

That is some 27ha of GPR survey, mostly at 50cm transect spacing.  That works out to pushing the mag some 540km across the field.  Figure 2 shows the final coverage.  As always, the image is a mess because it has been created by different pieces of software at different times and even with slightly different conversions of OS coordinates to lat and long.  My big job now is to turn that pig’s ear (processing-wise) into a clear image.

Figure 2: Done. The complete GPR survey of the theatre field (but needs better processing).

Many members of CAGG have contributed to the GPR survey over the last five seasons.  This season Nigel Harper-Scott, John  Ridge and John Dent have contributed greatly (Figure 3).  The person who really deserves a rest, however, is Mike Smith who has not only led the GPR team over most of the last five seasons, but has also been the main GPR transporter during the season, and has been looking after it during the week.  Many thanks Mike, and well done on a great achievement.

Figure 3: Nigel (left), Mike (centre) and John (right), today’s GPR crew.

The area covered this year is best seen via the stripes in the grass (Figure 4).

Figure 4: Stripy grass left by the GPR.

Now, you would have thought that completing the survey would have persuaded the boss to let them go home early.  Nope.  None of that slacking.  One grid we did at 1m transect intervals had an interesting building in it.  So after lunch the team set to once again to resurvey it at 0.5m intervals.  In figure 5 I have made the high amplitude reflections white so that the building can be seen more easily and placed it on the mag survey for context.  It is a long, thin, building with a corridor just visible on the eastern side and a larger group of rooms to the south.

Figure 5: the re-done block on the mag data.

Tomorrow, Mike gets his pick of which two squares to survey in Church Meadow.

The mag team re-did all the dodgy squares from yesterday, and quite a few more (Figure 6)!

Figure 6: the mag data in Church Meadow after day 5.

The mag team have just three whole squares for tomorrow, and then a few partials at the ends.  For most of its length, it is not going to be worth surveying up to the edge of the field to the NE as it is clearly into alluvium as shown by the flat, featureless mag data.  Figure 7 shows a close-up of the southern end of the survey.

Figure 7: the Church Meadow mag data, southern end details.

The darker curvy line is possibly an old edge to the river.  There are quite a few small dark blobs (“positive magnetic anomalies”) some of which could be graves, and at least part of a ditch feature.  I am still puzzled by the long negative linear.  I guess I’ll have to talk to some other geophysicists!

The res team was joined by Denley Lane of the Arc and Arc,  Denley remembers some of the pipelines being built.  The team completed an excellent seven grid squares.  Figure 8 shows the results, and Figure 9 shows the same results high-pass filtered.

Figure 8: the res results in Church Meadow after day 2.

Figure 9: the res results in Church Meadow after day 2, high pass filtered.

As can be seen, the building visible in the Google Earth image shows very well indeed, but there does not seem to be many more buildings to the south.  Tomorrow we will fill-in the one last block in the eastern corner, and then do a strip of blocks along the northern edge.

Tomorrow is the last day of the 2019 season.  I’ll be speaking about the Project at the International Conference on Archaeological Prospection on Wednesday.  Not much time to fit in the new results!

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s