Presentation on theme: "Digging Up the Past: Paleoanthropology and Archaeology"— Presentation transcript:
1 Digging Up the Past: Paleoanthropology and Archaeology
2 Lecture ObjectivesIdentify the importance of fossil in understanding the behavior and anatomy of ancient hominins.Identify the differences between paleoanthropology and archaeology.Compare the similarities and differences between relative and chronometric dating.Be able to identify and describes examples of relative and chronometric dating.
4 PaleoanthropologyBiological anthropology focus: study of earlier hominids, including184.108.40.206.Highly _____________
5 What do paleoanthropologists examine? FOSSILSRemember Cuvier – he recognized that fossils were once living organismsBUT fossils were not important in the realm of science until William Smith (engineering surveyor)Fossils are:Remains of organismsOrganisms which were wholly or partially transformed into rock through a long process of chemical replacement
6 Why Fossils? What information do they hold? Provide direct ______________Study of fossil centered on two factorsTime Environment
7 Taphonomy & Fossilization Commonly bones and teeth sources (comprise 99 % of fossil record)Taphonomy1.2.Hominid collapses & dies on shoreAfter the soft-tissue remains decay, only the skeleton is left. Footprints are left in the mudWater level rises, and lake sediments settle & cover the hominid’s bones and footprintsErosion exposes deep strata in a geologic column, revealing the fossil skeleton and footprintsBones fossilize in the thick layer of sediment at the bottom of the lake, while sediments continue to the deposited as layers. Other geological processes can occur, such as volcanic eruptions. As this happens, the fossil is embedded in a geologic stratum.
9 Dating – Why Bother? Placing sites and fossils into a time frame Dating techniquesRelative Dating Chronometric Dating (numerical dating) What is the numerical age?Isotope Dating rate at which various ___________ _____________________________________
10 Relative DatingTells the paleoanthropology that something is older or younger than something elseDoes provide:1.2.Does not provide:
11 Relative Dating #1: Stratigraphy Study of __________________________Variety of locations can be compared via chemical, physical and other propertiesLaw of _______________Lower stratum (layer) is older than a higher stratumProblemsEarth distributionsLength of time to accumulate stratum
12 Relative Dating #2: Biostratigraphy Employs the associations of fossils in strata to determine each _________________Aim is ________________Why?Demonstrates that a particular geological section in one location represents the _______________ as another geological section at some other section
13 Relative Dating #2: Biostratigraphy Index Fossils – _____________________Example of Irish Elk (died out: 10,600 yBP in Europe)
14 Relative Dating #2: Seriation Typological sequences of artifactsAssumption: ___________________Frequency of co-occurrence of artifacts in specific contexts_____________________Indicator of ____________________
15 Relative Dating #2: Seriation Example: Contextual seriationPottery -- style rather than function
16 Numerical DatingDating technique that gives an estimate in actual numbers of years_______________________We will cover both isotopic and non-isotopic methods:RadiocarbonRadiopotassiumArgon-ArgonWhy is this method useful?Certain radioactive isotopes of elements are unstable, disintegrate, & form an isotopic variation of another elementRadioactive materials forms an accurate geological time clock
17 Numerical Dating #1: Radiometric Carbon isotopes: Ratio of 14C to 12C is measuredBaseline for start of clock – death of organismBy calculating the ratio of 14C to 12C one can determine ______________________________Used for material younger than 50,000 – not the best for primate and human evolutionArchaeologists NOT __________________
18 Numerical Dating #2: Radiopotassium Non-organic material (e.g. igneous (volcanic) rock)40K decays slowly from its unstable form to a stable gas, 40Ar __________________________Dates material older than _________________Note – cannot date sedimentary rockFirst used at ____________________
19 Numerical Dating #3: Argon-Argon 40Ar – 39Ar: volcanic rock is bombarded with “fast” neutrons in a nuclear reactorAdvantage: ______________________________Example: ______________________
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