Methods
This page will explain the science of archaeology in terms of some of the methods applied to Paleolithic sites. An important point to bare in mind is that archaeological sites of any kind are a nonrenewable resource. Future study of any excavated site depends on the quality of the initial excavation and how thoroughly that information was recorded. A common way to approach a project is with a research design based on: 1) Formation of a research strategy, 2) Collection and recording of data, 3) Processing and analysis of recorded and collected data and, 4) Interpretation and publication of findings. This page is concerned with the second and third steps of research design (survey/excavation, and analysis respectively).
The first step in field archaeology is site location. This can happen in many different ways ranging from the unearthing of finds by large-scale public works projects, to private landowners coming forward with an interest in learning more about their own surface collections.
Survey
After a site has been discovered, survey and mapping takes place to define its boundaries. Survey is done using people and equipment to sample and test the sensitive areas. A transit and statia rod (like the kind used by the folks on the side of the road) can measure distances and establish datum points. Archaeologists can also walk transects, excavating sample units to find the limits of cultural deposits. At this time a site would be broken down into a coordinated grid system to organize the data retrieval done through excavation.
-Photo
of transit in use (property of Rumford Falls).
There are other ways to detect materials or artifacts under the ground, including sub-surface detection. One of these techniques is done with a proton magnetometer. A proton magnetometer works by using a sensor that is wrapped inside an electrical coil which is in turn supported by a rod or pole. These are then connected to an electronics backpack by a cable. The proton magnetometer detects small but noticeable differences in the magnetic field intensity caused by buried features or artifacts. Sub-surface detection as a rule, is a great tool for survey as it is non-invasive (it does not harm or upset the integrity of the deposit).
-Photo of proton
magnetometer in use at the Spiller farm Paleo-Indian site.
Above is a proton magnetometer readout from the Spiller farm Paleo-Indian
site. The feature delineated in the center is a hearth (see associated
photograph at the end of this page).
Excavation
The importance of excavating a site has not changed much over the past few years. A site is excavated to detect human behavior and change over time. An excavation occurs on a horizontal plane to detect relationships between artifacts of the same time period, and an excavation also occurs along a vertical axis to show relationships through time.
The vertical component of an excavation is usually done in levels. Levels might be natural or arbitrary. When levels are dug arbitrarily, a set amount of centimeters are removed until the bottom of a level is reached. When levels are dug naturally, archaeologists gauge by soil horizons. The vertical component of a site is also known as the sites stratigraphy.
The photo to the above left is a recreated excavation of a shell
midden exhibiting stratigraphy (from the Maine State Museum). Note the different layers of soil and
shell showing successive occupation. To the right is a cross sectional
photograph of an actual excavation unit (property of Rumford Falls). The
numbered tags delineate levels of strata.
Great care is taken in removing sediments from an excavation unit and artifacts within a level may be left in place to allow grid photographs and/or grid mapping. Once sediments have been removed from the unit, they are generally transported to a screening area where they can be processed. The screen allows soil to seep through while harvesting those smaller artifacts which might otherwise have been lost. Screen mesh sizing is largely dependent on the type of excavation. Fine screening (eighth of an inch or smaller) is recommended in excavations seeking recovery of faunal remains, microliths, etc..
There is much more to survey and excavation than has been described here, the whole process is quite dynamic in its ability to lend itself to specific characteristics of a site. The most important piece of information, which holds true for all projects, is to plan, retrieve, and record data thoroughly so that it might be restudied in the future.
Analysis
The analysis of a particular Paleo-Indian site consists of many techniques. This page will be broken down into two parts: analysis and dating methods. A wide array of methods are available to analyze and date a site, we will cover only a few which are often applicable to the Paleolithic. Consider the fact that so little survives in the archaeological record of a site which is thousands of years old, artifacts which were made from wood, bone, plant, and animal remains usually decompose before they can be procured through excavation.
13,000-9,000 years ago (the general time period Paleolithic archaeology is concerned with) there were different kinds of plants and animals inhabiting New England. Palynology, or pollen analysis, is a technique which helps to reconstruct these past landscapes. Since many plants produce pollen (some amount being blown into bogs and lakes), palynologists can use coring equipment to collect samples which have been preserved in wetlands. These samples can then be identified to tell what species were present at a given time.
In addition to pollen samples, the analysis of stone artifacts (which preserve well) is vital to Paleo archaeology. Defining tool styles allows comparison to different sites which might belong to the same time period. There are at least three different styles of points in New England.
Lithic sourcing provides a means to discover where artifacts had been procured. Sourcing raw materials might be as basic as seeking out natural outcroppings of the same material, or as complicated as making thin sections (cutting and polishing a rock to see its internal structure). The inferences of these types analysis will also be discussed further in the technology/trade page.
Establishing dates for archaeological sites can be done using methods broadly defined as being absolute (with reference to a specific time scale) or relative (typological sequences). Perhaps the best known dating method in archaeology is Radiocarbon, an absolute measure.
The above photograph is of a hearth at the Spiller farm site. Charcoal
(containing C14) samples were obtained from this feature in order to secure
radiocarbon dates.
Radiocarbon (C14) comes from our atmosphere and is absorbed by flora through photosynthesis, that flora may then be consumed by animals. Once the creature or plant dies, the intake of C14 ceases to occur and it begins to decay (nearly half of all the C14 is gone after 5730 years), this is called the "half-life" of radio carbon.
To date sites based on radio carbon, an organic sample is taken using great care to avoid contamination. The sample is then sent to a laboratory so that the half-life can be measured. Hearth features containing charcoal remains are excellent sources for radio carbon sampling.