Sunday, January 24, 2010

Core Sampling Project

As promised, here is the first two of Dr. Moshier's blogs reprinted with permission.

Blog Entry: A big pile of sand (posted July 1, 2009)

All of my T-shirts have brown stains on the part over my belly. The hotel laundry just can't wash out the silt and clay that we are drilling out of Tell Ashkelon. I think the size of the stain is proportional to the size of the belly, a theory confirmed by a quick look at individuals in the pottery compound. I think I’ll have salad tonight for dinner.

The dirt doesn't seem to show as much on my pants, as they are very pale brown to begin with, a shade close to 10YR7/4 on the Munsell scale of soil colors. My typically pale “white” skin color is changed, too, either due to the sun or the absorption of Holy Land clay into my pores. Sunscreen only serves to give the clay something to stick to. Even after rigorous scrubbing in the shower, mud still smears the towel.

On Monday we started a second round of drilling. Archaeology students Ben and David assisted me again. Our driller Efni showed up at the park with his rig at 7 AM. We had been there since 5 AM. Efni packs up and leaves at 3PM and there is no time for lunch before he leaves. Our strategy Monday morning was to push up close to some of the excavation sites. The archaeologists know that the Middle Bronze settlement is built on a cover of yellow sand that extends beyond the (safe) level of excavation. Is the sand part of a dune that covers older cultures? We really wanted to punch through that sand to find out.

The drill is called a bucket auger that looks like a medium-size garbage can with jaws. The rig is mounted on a large tractor that is part forklift and part bulldozer. The drill string rotates and lengthens like a radio antenna, as the bucket churns down through the sediment. It is strong enough to grind through soft rock like the local sandstone, but the scraping sounds like fingernails on a blackboard and louder than a dinosaur in Jurassic Park. When the bucket is full with about 30 to 40 cm of sediment, the drill string is retracted and the bucket returns to the surface. The driller mechanically shakes the sediment out of the bucket, which falls on the ground for examination and sampling.

If everything goes well we can reach a total depth of 11 meters below the surface. Things did not go well Monday morning. At about five meters depth we encountered the yellow sand, but the sand was dry and started caving into the hole. We typically have to pour one or two standard buckets of water down the hole every time the auger goes down in dry sand. The water gives the sand cohesion and conditions the side of the hole to prevent caving. The idea of pouring fresh water down a dry hole seems ironic and perverse. It just did not work and we never got deeper than six meters. We moved the rig about 4 m to the side and tried again with the same results. If there is if there is older archaeological material beneath the sand, we will have to find a better method of drilling to find it. Next, we moved to another location near an excavation site. Same thing. Dry caving sand. Excavation Director Daniel Master stopped by to hear my complaints and told me, “Tell Ashkelon does not easily give up its secrets.”

The last three probes on Monday were more successful. We drilled in the main parking lot located between the north and south tells. The lot was probed in the 1980s but the reports from that survey are difficult to interpret because the descriptions are ambiguous and the depths don’t seem correct. We have good data now and that is the important thing. Even if I offer a lousy interpretation, I want our descriptions of the material and stratigraphy to be useful to future scholars working here.

On Tuesday we started by drilling very close to the beach cliff next to the south rampart built by Crusaders. The goal is to trace deposits evident on the beach cliff landward. Drilling was painfully slow through the sand. David and Ben carried gallons and gallons of water (uphill) from a park faucet some 50 m away from the drill sites. At about 9 AM the cable on the drill rig snapped. Efni called someone to come with a new cable. We were down for about 30 minutes. I fell asleep in the shade sitting up with my legs crossed on the ground. It was hot, but we had a constant breeze from the sea.

The next probe turned out to be our last of the season. It took nearly four hours to drill 10.4 m. We needed lots of water to get through the sand. David and Ben got quite a workout carrying jerry cans of water from an irrigation tap David found about 75 m from the drill site. I wanted to find a place where we would drill to bedrock. We have all assumed that hard sandstone, called kurkar, underlies the tell because it is exposed to elevations of up to 18 m above sea level. But, we have never encountered hard sandstone in our course landward under the tell. We do encounter lots of sand (remember the dry yellow sand from Monday?). We should have reached hard rock in our first probe near the south rampart beach cliff, but we did not. So for this probe we moved the rig to the north tell and set up near the cliff face (about as close as we could safely put it). We should have reached hard rock there, but again we did not! So it appears that the hard rock only occurs along the beach cliff. Hypothetically, the ancient sand dunes that formed the original topography of the tell were only cemented in this narrow zone against the sea. Seawater contains the dissolved calcium and carbonate that probably cemented the rock. We find no other obvious source of rock for the crusader ramparts and structures than the area of the beach cliff and a small quarry close to the cliff on the north tell. It seems then, when we encounter yellow sand anywhere under the tell, we are at, or near, the level of the original topography of the tell. Ashkelon appears to be built on a pile of sand. Our drilling efforts have provided the data to reconstruct the original topography of the site before human habitation and modification of the land.

We did not always encounter what we expected (that would be too easy). But perhaps Tell Ashkelon is beginning to reveal some of its geological secrets after all.

Read more from Dr. Moshier and his team next time to learn more about how geology is contributing to the archaeological exploration of ancient Ashkelon.

Archaeology, It's Not Just For Archaeologists Anymore

"What, where, when?"

First things first, the answer to last month's "What, where, when?" is that the photo shows a Roman period road discovered during the 1992 season. The road and its associated drains were excavated in Grid 2 on the North Tell just outside the ancient city walls. Though exposed the street was never fully excavated and today it is buried under the parking lot just outside the Canaanite Gate

Technology, or How We Get Things Done

The privilege of old age is that I can reminisce with little rhyme or reason about the things that manage to stick out in my memory. So, here are some random thoughts that have managed to linger in the deep recesses of my mind.

Unsurprisingly, over the 20 plus years since I first went to Ashkelon there has been a great deal of change particularly in how we do things. Maybe not going from a horse and carriage to a car level of change but certainly revolutions in both technology and methodology that have changed how we investigate the ancient city. Yep, how we investigate the site and how we stay connected with the wider world as we live in the whirlwind that is an excavation season.

For instance, back in the day technology at Ashkelon meant those ultra thin, light weight air mail letters you could send home. You know the ones you fold and seal shut no envelope needed. That was pretty fancy stuff.

Archaeologically speaking pencil and paper were the recording tools of trade and the only computer on site was a cranky old thing in the dig office that all the supervisors shared along with the team of dig registrars. At the end of the season when square reports were due BEFORE the final dig party that machine saw a great deal of love and attention.

By the early 90s we advanced sufficiently to have access to e-mail. By “access” I mean that the e-mail was sent to the aforementioned cranky old beast in the dig office where it was then downloaded and printed (one screenshot at a time) before being distributed to the designated recipients. And by “we” I mean members of the professional staff. In other words, while a limited few of us had e-mail we had little privacy and certainly few secrets. Did I mention that e-mail came via a 300 baud modem? For those of you not old enough to know what that is, imagine a bunch of hungry alley-cats fighting over food and then toss in a chorus of crying babies. Finally, drop a spoon into the kitchen disposal, listen to all those glorious sounds together and you’re just about there.

Today things are quite a bit different. Pencils and paper are a thing of the past. We actually use laptops in the field to do all our data entry. Anyone with a laptop and I do mean anyone has access to e-mail and the joys of the internet. Need to check the score of the Cubs’s game? You can do that -- just about anywhere you want. Need to update your Facebook page? Doable.

The pervasiveness of computers, both in and out of the field, isn’t the only thing that is different about Ashkelon and the way we do things. In the past few seasons we have started some new projects, one doing ground penetrating radar and another doing core sampling, to help us investigate more areas of the site. These projects use methods that are less invasive than traditional excavation and not only do they help to further our research goals but also they help to shape those goals.

The core sampling project is headed by the team’s geologist Dr. Stephen Moshier who is an Associate Professor of Geology at Wheaton College, Illinois.

Born and raised in upstate New York Dr. Moshier studied geology at Virginia Tech (BS, 1977), SUNY Binghamton (MA, 1980) and Louisiana State University (PhD, 1987). His previous professional experience included working in the petroleum industry and a faculty position at the University of Kentucky. His teaching responsibilities cover areas of general geology, earth history, sedimentary petrology, and geoarchaeology. Prior to 2000, professional interests were focused on ancient limestones and petroleum geology. From 2000 to 2007, Moshier served as team geologist for the Tell el-Borg excavation in the NW Sinai, Egypt and in 2008 he joined the Harvard University-Leon Levy Expedition to Askhelon, Israel.

Dr. Moshier has generously allowed me to reprint some of his blog entries about his work during the 2009 season. The first of two entries will follow after this one.

Now, for the latest “What, where, when?” Any ideas?

One final note, we have a new website for you to check out. The address is Visit it to see our flyer about the upcoming season. The site is still under development but check back in the future to see more about Ashkelon and what we do. We also have a new e-mail address,

Thanks and see you next time!