Magnetic Gradiometry at Jebel Barkal
7 December 2018
By Gregory Tucker
This week for #fieldworkfriday I would like to share with you a bit of where I am and what I’m doing in the field. This month I’ve come to Sudan’s Northern State, to the site of Jebel Barkal, near the Fourth Cataract of the Nile, to conduct a geophysical survey in two distinct areas of the site.
Jebel Barkal is a small mountain not far from the Nile that was considered by the Egyptians and later the Kushites to be the home of the god Amun. Various temples, palaces, and pyramids were constructed at the site from the Egyptian New Kingdom (about 1500 BCE) to the end of the empire of Kush (about 300 CE), and these have been the targets of extensive excavation in modern times. Jebel Barkal and the nearby sites of El Kurru, Sanam, and Zuma are on the UNESCO World Heritage List.
Geophysical survey is one of the most efficient ways to explore a large landscape like that of Jebel Barkal in search of specific features that will help us understand how people lived in the past. The results of this month of survey will help our projects better understand and interpret the built environment of the site, shedding light on how the community at Jebel Barkal lived and how it relates to other sites and their architectural traditions from the region.
This past week we finished up our work for the first project, on the south side of the mountain, where we were working in the desert landscape near the pyramids at the site. We were invited to survey this area by Murtada Bushara Mohamed of Sudan’s National Corporation for Antiquities and Museums (NCAM) as part of the Qatari Mission for the Pyramids of Sudan (QMPS) project. This project is focused on research, preservation, and presentation of the pyramids at Jebel Barkal, Kurru, Meroe, and Nuri and our contribution will help us better understand the landscape context of these monuments by identifying the location of other structures in this region of Jebel Barkal.
Tomorrow we will begin our work on the east side of the jebel, between the mountain and the Nile River, in an area we call the “East Mound.” This project is an offshoot of Geoff Emberling’s research at El Kurru and the surrounding region, and during preliminary research conducted in 2016 we identified this mound as being a likely location for the settlement associated with the temples and palaces of the monumental core of the site. We were able to identify buried structures here during a very short period of survey that year, just a couple of days, so we have returned to survey the entire mound and the surrounding area to better define the extent of this settlement.
The type of prospection that I’m conducting can be done with many different instruments, each with its own unique method of collecting magnetic data. In the case of this project I am using a device that must be carried across the landscape and takes readings at consistent intervals.
The most efficient way to use this device is to set up a grid in the area that we wish to cover. Using a total station we establish a 30 x 30 m grid, and within that grid we lay down guidelines that are marked at every meter. Then, wearing the scientific device, I walk up and down along the guidelines, which are there to ensure that I walk straight and at a consistent pace.
By telling the instrument and the processing software the parameters of the survey, the data can be plotted quite quickly to create a map of the magnetic readings at the surface, giving us insight into what may lie buried below. With this particular machine we are limited only by how fast I can walk while maintaining a consistent pace and holding the machine relatively steady, which depends on the surface conditions — sand slows me down quite a lot! — and how well we have established the grid and the guidelines. Below is a short video that gives a first-person perspective of what walking one of these lines is like. (In a typical day I can walk approximately 540 lines!)
Of course, there is slightly more to it than just that, but the bulk of my time here is spent walking along these lines and listening to the machine chirp at me, 30 meters at a time.
I realize that I did not check the comments on my last post to see if there were any questions, but I will be better about that this week, so please comment with any questions you may have or email me at email@example.com. I would love to hear from you! And please check in next week for another update from Sudan!
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 This research was undertaken thanks to a Waitt Grant from the National Geographic Society for my project: “Defining Settlement in the Nile Valley: Geophysical Prospection in the Region of Jebel Barkal, Ancient Napata.” For more about the results of this work, see Tucker and Emberling, “Settlement in the Heartland of Napatan Kush: Preliminary Results of Magnetic Gradiometry at El-Kurru, Sanam, and Jebel Barkal,” Sudan & Nubia 20 (2016): 16–22.