Magnetometry

AROURA Project – archaeological reconnaissance in Greece

Molly Greenhouse, Teaching Assistant, ARCH 397, UMBC

The AROURA project (Archaeological Reconnaissance of Uninvestigated Remains of Agriculture) is an archaeological survey of the plain around the 13th century BCE fortress of Glas, Boiotia, in central mainland Greece. It aims to detail the Mycenaean hydraulic, drainage, and land-improvement works around the fortress, and to search for traces of the expected extensive agricultural system they served. AROURA is an official collaboration between the University of Maryland, Baltimore County (UMBC), and the 9th Ephorate of Prehistoric and Classical Antiquities (IX EPCA) of the Hellenic Ministry of Culture and Sports, based in Thebes, Dr. Michael Lane (UMBC) and Dr. Alexandra Charami (IX EPCA) co-directors.

The survey and surface collection phases of the project began in October of 2010, and have since been completed. The entire project area was divided into grid squares at the outset to allow investigators to conduct geophysical survey easily and systematically across large portions of the plain, using techniques like magnetometry to detect underground “anomalies” that might be traces of previous land use. In certain grid squares, both in the plain and at the nearby settlement site of Aghia Marina Pyrghos, finds were collected from the surface of the ground too. Our goal this season is to organize, catalog, and analyze the many finds, mainly pottery, collected during previous years.

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All of the finds are stored at the Archaeological Museum of Thebes, so during the week, we travel there from our home in the village of Kokkino to work on the collection. Currently, we are working on the pottery from surface collection at Aghia Marina Pyrghos. After labeling each piece and ensuring that it is properly catalogued, we start to focus on more in-depth analysis of the pottery. In the lab, we carefully examine the artifacts and record basic information about the size and shape of the pieces, as well as other more detailed information. We have been closely examining the pottery for mineral inclusions in its fabric (the constituents of the clay from which it is made). Examining hundreds of individual pieces of pottery with a magnifying glass to spot inclusions can be tedious work. However, by collecting this kind of information, we hope to be able to draw conclusions about the periods represented by the pottery and other artifacts at the settlement and where the pottery originated, as well as to hypothesize about how it made its way to the settlement.

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Working at the museum in Thebes has been wonderful so far, and it definitely has had its perks. For example, this week, after Prof. Vassileios L. Aravantinos, the former Superintendent of the IX EPCA, dropped in for a surprise visit, we were invited to tour some of the ongoing excavations of the Mycenaean palace beneath downtown Thebes. We are excited to see what results the rest of this season will produce and how the project will expand and develop in future seasons!

Arghhh, please, not one of THOSE days!!

After spending a beautiful, sunny day in the field gathering geophysical data, the office awaits me. Data must be processed, they said!

There were no problems with the GPR and magnetometry. The site was a nice, even lawn and like a football field. It was a location near the Dutch coast with clear blue skies & fish for lunch. What a way to collect your data!!!

But the problems started the day after.

8.00 am

Euhm, where is my backup USB with the data? Can’t find it. And who took my fieldlaptop this morning?

Please, do not let this happen to me.

Oh, there it is. Pfew

9.00 am

processing GPR data. Hmmm, there are a lot of fielddrains visible in the data. This former soccer field clearly needed draining. I hope it doesn’t obscure my relevant data too much.

Oh, thanks very much, this visual basic software from a previous century keeps crashing. What is wrong, and where is the corrupted file? Checking lots of files one by one.

10.00 am

several  phone calls:

  • ‘yes, sir. We can do that. Oh, you want us to do the survey by the end of this week? Hmmm.’
  • ‘oh, were you expecting the report yesterday?’
  • ‘No, sorry. We can’t go any lower with our costs. Yes, you’re free to look for another geofyzz company.’

11.00 am

Oh, my God. I can’t believe the amount of recent rubble just below the subsurface. This red brick demolition waste is masking my magneto-data. Let’s see if I can fix this. Sigh.

The small archaeological excavations from the 80’s and 90’s do provide additional information, but why do their pits/trenches have to be so visible in my data! Go away!!

12.00 pm

Blue screen of Death

13.00 pm

Yep, several of those phone calls you do NOT want to deal with right now.

But just have to.

14.00 pm

Oh great, I have an inbox full of email. Let’s see if some procrastination will make my day.

14.30 pm

Euhmm, do you really want a financial forecast of these projects? You mean as in right now? But…

15.00 pm

postprocessing, filtering, enhancing, gnashing of teeth, munching pencil stubs. Login to GIS failed. Out of memory. Why am I not out in the field? Merrily singing aloud while gathering data. HELP!!

16.00 pm

But WOOT? Is that….yes..the former foundations. Hurray, here they are! And the results from the GPR differ from magnetometry, but combined they give very interesting anomalies.

Let’s make an appointment with the archaeologist to start some interpretation next week.

While humming a joyful tune, I shut down my computer.  Another day at the office. While all the odds seemed working against me today, I obtained some very interesting results.

Big smile!! I do love geofyzz.

walking with magnetometry multisensor cart

Walking with magnetometry multisensor cart

GPR behind the quad

GPR behind the quad

disturbances in the mag-data

Disturbances in the mag data

interesting features!

Interesting features!

lots of drains!!

Lots of drains!!


Isola Sacra – Existing Features

So the survey at the Isola Sacra has been running for the last three years. The area comprises an artificial island between Portus and Ostia Antica with the line of the Via Flavia running from north to south. A number of questions are being directed at the area, in particular relating to the location of the ancient coastline in the Roman period, the division and make-up of the ancient landscape an the presence or absence of buildings, workshop zones, cemeteries and other sites.

One thing that has stemmed from the survey to date is the presence of ancient canals sub-dividing the area, a small example of which appears below.

More of the same being processed at the moment suggesting the continuation of similar features. The area is marked by broad geological features also, all relating to the prograding of the Tiber delta in antiquity. For more information see www.portusproject.org/ and http://www.portusproject.org/fieldwork2007-9/regionalsurvey/results.html and http://bsr.academia.edu/StephenKay/Papers/185232/The_role_of_Integrated_Geophysical_Survey_methods_in_the_assessment_of_archaeological_landscapes_the_case_of_Portus.

Day of data processing – geophysical survey results from Isola Sacra

A day of processing of data, starting with the latest results from the geophysical survey at Isola Sacra, near Fiumicino, Italy.

 

 

This image shows a member of the survey team last year surveying using a fluxgate gradiometer over the central part of the landscape, an area of floodplain between the course of the river Tiber and the small Fossa Traiana, which demarcates the Isola Sacra between Portus and Ostia Antica. So far some 120 hectares of data have been collected, and the latest stage of processing is under way. More to follow later.