Important principles for interpreting change in the world and for understanding the fossil record 1 Uniformitarianism Rates and processes in the past were the same as can be observed today 2 Steno s Law or the Law of Superposition In undisturbed deposits deeper strata will be older BASIC VOCABULARY Artifact an object made used or altered by humans Fossils are rocks They may be mineralized organic remains such as bones turned to rock or they may be impressions such as footprints Fossil locality a place where fossils are found Site a place where human activity occurred NOT where archaeologists dig it is a site whether or not it is found or excavated Fossil localities occur only under special conditions of preservation Taphonomy the study of the processes that affect bones after the death of an animal Examples of artifacts Rhyolite debitage from flintknapping A point a biface Pottery sherds Archaeologists study human behavior through material remains They are interested in uncovering clues to culture and they excavate at archaeological sites Paleoanthropologists search for an understanding of early humans and human ancestors They excavate at fossil localities which may also be archaeological sites Midden trash mixed with dirt May occur spread across an area as a sheet midden or it may fill a feature Usually black in color Matrix the dirt that holds and supports artifacts and features Sterile dirt that contains no cultural remains Living floor surface ancient surface upon which activities took place Feature a non portable artifact embedded in the matrix such as a hearth or postmold w e vi th a w an wi vie l P p e a ey m srd i b postmolds where a wooden post used to be How can an archaeologist define a feature Several clues in the field 1 Different texture 2 Different color often dark because filled with midden 3 Contains artifacts 4 Shape size of it helps Provenience exact horizontal and vertical location of something Datum a reference point made at a site or fossil locality for establishing a grid horizontal mapping and vertical reference Since we are interested in human behavior archaeologists and paleoanthropologists act like CSI investigators The context and association of artifacts features living floors etc are important for interpreting the behavior Mapping the provenience Horizontal mapping Vertical mapping This big nail acts as a vertical datum for a unit Stratigraphy layering Could be layers of dirt at an archaeological or paleontological site Could be layers of rock Stratum a layer Strata layers plural As we ll talk about next class deeper strata are older N332 E428 E1 2 West Profile w e i v ew e l f s vi o r P ay w e d i s Plow zone Second stage Basket laid fill nearly sterile silty clay 3 colors First mound stage silty clay loam loaded with artifacts Midden Ab horizon silty clay B horizon silty clay sterile DEPOSITION We need to be able to distinguish NATURAL deposition from CULTURAL deposition So an archaeologist needs to know a lot about dirt and soil formation processes Three steps or stages to archaeological investigations 1 Survey to find sites 2 Test the sites you found to learn basic info 3 Excavate those sites of interest to learn details How do we fnd fossil localities or archaeological sites Survey a systematic examination of an area to find sites fossil localities Take environmental and past environmental topographical and geological conditions into consideration in targeting likely areas To find old sites you must look in old dirt To survey May walk and look on surface for artifacts or fossils Works best for artifacts if it is a plowed field Works best for fossils if it is an eroded bare dirt surface Here in South Carolina archaeologists dig shovel test pits in regular grids looking for artifacts and cultural dirt midden beneath the near surface Shovel test pits Test each site Looking for time period size type of site Integrity is any of the site still intact is it worth excavation Generally in testing you want to examine the stratigraphy in just small areas or test units Belmont Neck site SC Summer 2004 Part of testing a site may include remote sensing a technique to examine what is underground before you dig into the ground Examples of remote sensing Using metal detector historic sites with metal Proton magnetometry measure magnetic field Electrical resistivity Ground penetrating radar Magnetometer Measures intensity of magnetic field or magnetic anomalies underground http www geomodel com em http www nd edu mschurr bennac97 html Soil Resistivity By sticking metal probes in the ground and running an electric current between them Measure differences in electrical resistivity ability of deposits to conduct electrical current For example walls and roads high resistivity pits low http www nd edu mschurr geophys html geophys Resistivity readings overlaid on topo map of historic Mandan earthlodge fortified village http www cast uark edu kkvamme geop double htm Ground Penetrating Radar electromagnetic waves reflect back as echoes from interfaces Is especially good for finding layers Instrument can be set to look at a specific range of depth Pulling the instrument http www geomodel com Readout showing 3 buried metal tanks Locating pit houses in the Southwest http www du edu lconyer pit houses htm May excavate the site Excavation generally opens up a horizontal area of one time period Berry site NC 1500s Spanish house burnt by Indians Shovel Scraping Shovel scraping allows a lot of dirt to be removed quickly yet one can still keep track of dirt colors Note the buffer left around the edges to protect the unit walls from the shovel Cut profles When a level is complete the extra dirt is cut away This is called cutting the profiles The string at the surface marks the ideal shape of the unit Trowelling Trowelling is slower than shovel scraping but leaves a level surface with cleanly cut dirt that shows the dirt colors or feature edges Mapping and measurements We measure the depth below a temporary datum using a line level We measure the depth to the top and the bottom of each level Dirt colors the outlines of features and certain artifacts are mapped at the top of each level We also map the profiles Simple stamped sherds were found in Feature 5 dating it to the Late Woodland period Except for flotation samples all the dirt is dry screened through inch mesh Everything found in the screen is saved and later washed Unscreened dirt saved for flotation is carefully measured
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