Methods of Historical Investigation How do we know about the past?

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Methods of Historical Investigation How do we know about the past? Slide 2 Primary and secondary sources Primary sources are those that come from the time being investigated. Secondary sources are written or produced after the period they describe. LettersSpeeches Eyewitness description Official documents Modern historian Textbook EncyclopaediaRe-enactments Slide 3 Types of Sources Written Sources include:Non-written Sources include: Histories Plays and poetry Legends Letters Inscriptions Laws Administrative Records Graffiti Buildings Monuments Tombs Skeletal remains Pottery Tools and weapons Household goods Coins Slide 4 How reliable are our written sources? Truth or bias? Purpose for writing Personal beliefs or opinions Limited access to evidence Slide 5 What is Archaeology? Archaeology is a way of studying the human past through physical remains (artefacts). Artefacts are any objects made, used or modified by humans. Archaeologists are Time Detectives Slide 6 Investigating the Evidence Observation Where was the artefact located? What is its possible age? Who made it? What might it have been used for? Who put it there? Classification & Recording Classifying according to time and place Is it authentic? What can be learnt from it? Does it contradict or complement other evidence from the site? Interpretation Interpret the evidence Look for patterns What conclusions, inferences or assumptions can be drawn? Slide 7 How are artefacts dated? Relative Dating MethodsAbsolute Dating Methods Stratification Typology Cross-dating Fluorine testing Paleontological dating Pollen analysis Carbon-14 dating Potassium-argon dating Dendochronology Thermoluminescence Intel Education: Student Login Slide 8 Stratification Slide 9 Typology Many artefacts can be dated according to their style. For example, pottery, tools and weapons show distinct styles at different periods of development (compare with how models of cars have changed over the years). Slide 10 Cross-dating If a particular style of helmet, pottery, etc is able to be dated at one particular site, then this can be used to date other sites in which the same style of artefact is found. Slide 11 Fluorine Testing Slide 12 Paleontological Dating Palaeontologists study the history of animals. Often a site can be dated according to the types of animal fossils found there. Slide 13 Pollen Analysis Cranesmoor bog is formed over lake muds estimated from pollen analysis to have been laid down in early Boreal times, and the overlying peat is up to 15 feet deep in parts. The peat consists mainly of either Sphagnum or Schoenus nigricans remains, and the present surface vegetation shows a similar variation associated with hydrological differences in different parts of the bog. [Information from a botany report available on the "New Forest History" website: http://www.hants.gov.uk/newforesthistory/ ] http://www.hants.gov.uk/newforesthistory/ Slide 14 Carbon-14 Dating Slide 15 Potassium-argon Dating The landscape in the central Andes Mountains, near the border between Chile and Argentina, is dominated by volcanoes and associated landforms. Layers of older sedimentary rocks are visible to the upper middle, and many volcanic cones show grooves where water has eroded the rock to form gullies. A few volcanoes exhibit much less erosion, and even show tongues of dark, recent lava flows (upper left). Slide 16 Dendrochronology Sample from wood is taken with hollow drill. Samples from woods those have partly different age, can combine together to make tree-ring sequence, that can be presented like thicker tree or longer stick. Drill to take samples for Dendrochronology from trees Slide 17 Thermoluminescence Slide 18 Comparative Chart: Dating Methods Can tell us:AccuracyWhat ?Any Problems StratificationThe order of occupation Relative only earlier or later Any finds in situ TypologyApproximate date made Relative only - new/late model Man-made items Cross-datingNot earlier than...Relative: one find used to date other Man-made items Fluorine TestingTime of burialRelative only (see problems) Bones, teeth, antlers, ivory Temperature Soil chemistry PaleontologicalWhat animals?Appearance and extinction period Animals Pollen AnalysisEvidence of climate Grains will survive for 1000s of years PlantsOnly history of the vegetation Carbon-14Time of death + or 100 years To 50,000 years Organic material (certain amount) Destruction Contamination Potassium-ArgonAge of rock layersTo millions of yearsVolcanic RockLimited sites DendrochronologyAge of timberDates layer to yearTimberRequires time sequence Thermo- luminescence Original firing date > Typology To 35, 000 years Fired pottery & clay