Biweekly Update 22 July 2016

22Jul2016

Image | Posted on by | Leave a comment

Phase I Archaeological Survey

by Erica D’EliaAssistant Lab Director

If you have been following our biweekly updates you already know that the CART team is hard at work surveying a new site. But you might not be familiar with what this entails. This work is being conducted consistent with Fairfax County Park Policies 103 and 203 and in accordance with Virginia Department of Historic Resources (VDHR) guidelines which designates different phases of archaeological work and objectives for each. We are currently performing a Phase I Survey with the goals of identifying any historic or prehistoric sites located on the park, defining the boundaries of any sites discovered, and assessing the need for Phase II work. Phase II involves determining the significance of the resource.  Archaeological sites can be considered significant under either National Register of Historic Places criteria developed by the National Park Service or under local criteria developed by Fairfax County. It is always preferable to avoid disturbing a locally or nationally significant site. However, if avoidance is not prudent or feasible, a Phase III entails the development of a treatment plan in consultation with VDHR.

In order to identify sites within the park’s boundaries we use a systematic survey of the property. Typically, this takes the form of shovel test pits (STPs) dug at regular intervals along a grid. So let’s pretend that this square outline is our park.

neIn the field, our first task was to establish a baseline in the form of Cartesian grid from which to conduct our work. In order to keep track of where we are on our grid we use a system of coordinates called Northing and Easting. In this example the point furthest southwest is our datum (the red dot on the image below) or the point from which we measure all other points on the site (and now you know how the Archaeological Society of VirginiaNorthern Virginia Chapter’s monthly publication, the Datum Point, got its name!) Its coordinates are North 0/East 0 (N0/E0). Using a surveyor’s total station from the datum we shot in a line of points (black dots) 15 meters apart running West-East. This is our baseline (blue line).stpongrid

To get a sense of our grid imagine lines running North-South and East-West every 15 meters. These are called transects, represented by dashed lines in the image below.

GRID

Now, the real fun begins. We work in teams of two and move North along each point digging a small hole every fifteen meters. Eventually we’ll dig holes across the entire site. As you move North the Northing increases, likewise, as you move East the Easting increases. In the image below each dot represents an STP. The STP represented by the green dot is located at N60/E45 and the purple dot is N30/E90. Can you figure out the coordinates for the yellow dot?

Gridloc

Of course these maps are pretty ideal. In the real world parks aren’t perfect squares and their boundaries do not align along cardinal directions, Plus, we’re in the woods, so we have all sorts of fun tree, vine, and thorn obstacles. Not to mention the ticks, mosquitoes, and poison ivy. We use a compass and measuring tape or pace out how many steps we take in 15 meters to make sure we are moving in the correct direction the correct distance.

Digging an STP is relatively simple. We’ll mark a piece of flagging tape with the coordinates and tie it to a nearby tree. Then, we’ll clear the ground surface. We’ll take note of any interesting natural or cultural features nearby such as trash scatters or creeks. Using a shovel we’ll create a circular outline where we’ll dig our hole, typically about 40 cm in diameter. As we dig the hole we’ll pay careful attention to any changes in soil color, texture, and composition as that indicates different natural or cultural processes that occurred over time. Once we’ve excavated no less than 10 cm into subsoil (unless we hit an obstruction or it fills with water) we’ll know we are finished. All of the soil is screened through ¼” mesh so that we can recover any artifacts. We might find historic period artifacts such as glassware, nails, and ceramics or we might find prehistoric flakes and stone tools. Although finding artifacts is always exciting, the truth is most of our STPs are negative, meaning no artifacts were found.

messystp

Recordation is extremely important to all stages of archaeology. We take notes about every STP we dig. We record things like the depth of each layer, any artifacts found, and use Munsell books to describe the soil. When we’re finished we fill the hole back in and move to the next location to repeat the process.

As we continue the survey we will start to note certain patterns; areas where we found artifacts and areas where we did not. This helps us to determine the locations of archaeological sites and make plans for additional work in those areas. In the map below pink dots represent prehistoric artifacts and the yellow dots represent historic artifacts. The circles correspond with artifact clusters defining potential sites. If any of these sites exhibit potential research value, it is on to Phase II…

findGRIDloc

(Answer: The yellow dot is located at N120/E120)

 

Posted in Archaeological Survey | Leave a comment

Congratulations!!!

Elizabeth Paynter, our lab director, is being recognized at the county level for her excellent work!  It was just announced today that Elizabeth will receive an Outstanding Performance Award at a ceremony on July 22 at the Government Center.  Congratulations!  It is well-deserved!

county_sealFCPA logo Color version

Posted in Uncategorized | Leave a comment

Day of Archaeology Festival

Mark your calendars.  This Saturday, July 16, 2016, CART will be one of a host of local archaeological organization taking park in Archaeology in the Community‘s Day of Archaeology Festival!  The event will be at the Dumbarton House, 2715 Q St. NW, Washington D.C. from 10 a.m. until 3 p.m.  This is a great way to see all the archaeology going on in the greater Washington D.C. area.  Hope to see you there!

doaf_-041116

Posted in Uncategorized | Leave a comment

Biweekly Update – 8 July 2016

08Jul2016

Image | Posted on by | Leave a comment

Understanding Basics of Lithic Production

by Jonathan BrisendineArchaeological Field and Lab Tech

Almost everyone knows the basic appearance of a projectile point otherwise known as an arrow head. Early projectile points were made of lithic (stone). However, if asked, few would be able to explain how a projectile point is created from a rock. Hopefully after this post you will better understand how a rock is transformed into an early American lithic tool.

JBLithic1Most often the type of material used is dependent on what is available locally, that which can be found in travel or obtained through trade. For Fairfax County the most common lithic materials found are quartz, rhyolite, and quartzite. A desirable lithic material is one that will break or flake in a predictable manner . Once a suitable rock is found, large flakes of stone are removed from that parent rock. The flakes and debris removed are known as debitage. Removal is done by striking the parent material (the core) with either a hammerstone or a billet.

JBLithic2There are two main techniques of producing the end product. One is to remove the flakes as seen in step 1 and the goal to use the core as the final product. The other, discussed here, is to prepare the core so that a next flake removed has the basic proportions and characteristics that you require for the tool. Chips or flakes are removed from the core. Then a larger flake will be removed from the core in a form that can be used as a tool.

JBLithic5

Once the flake in the basic shape of the desired end product, it is time to refine both the shape and sharpen the point. This is done in a similar method of step 1 but on a smaller scale. The process is called micro flaking. Micro Flaking is most often done method called pressure flaking. Pressure flaking is achieved by using an antler to press along the edges of a tool in order to remove small and controlled flakes.JBLithic3

Final Product!

JBLithic4

Posted in Archaeology | Tagged | Leave a comment

A Star is Born???

 

…well, maybe not so much.  However, Christopher Sperling, Senior Archaeologist with the Fairfax County Park Authority was the guest on Virginia Time Travel on June 23 on Fairfax Public Access (Cox and Verizon) Channel 10.  Click on the image above to see a YouTube of Chris discussing excavations at the Old Colchester Park and Preserve as well archaeology in Fairfax County more generally.  If you miss it, the program will be re-broadcast on Friday (6/24) at 9:30 p.m. and Tuesday (6/28) at 6 p.m. So, no shortage of ways to see this guy way out of his element!

 

 

Posted in Uncategorized | Leave a comment