The Mystery of The Mystery of the Guangala the Guangala

Obsidian:Obsidian:

A Functional Examination A Functional Examination Through Experimental Through Experimental

ArchaeologyArchaeology

……Thousands Thousands of years of years later…later…

Nature of ExperimentNature of Experiment Choose artifactsChoose artifacts Create replicas using experimental Create replicas using experimental

methodsmethods Use replicas on various contact materialsUse replicas on various contact materials Use microscopy to examine damage on Use microscopy to examine damage on

artifacts and replicasartifacts and replicas Compare replicas to artifactsCompare replicas to artifacts Draw conclusions about function of the Draw conclusions about function of the

obsidian bladesobsidian blades

History of the GuangalaHistory of the Guangala● Culture flourished from 100 BC-800 AD• Lived in Southern Coastal Ecuador• Artifacts and descendant cultures provide clues• Many questions unanswered

Culture and SocietyCulture and Society

Religion: animisticReligion: animistic Beauty: tattooing, Beauty: tattooing,

body painting, body painting, piercingpiercing

Clothing: cottonClothing: cotton

Lifestyle Revealed Lifestyle Revealed Through ArtifactsThrough Artifacts

GrindstoneGrindstone Agriculture AgricultureFish hooks Fish hooks Fishing FishingForeign resources Foreign resources Trade TradeObsidian Obsidian ??? ???

FlintknappingFlintknapping Process of manufacturing stone Process of manufacturing stone

toolstools– Works because brittle stone Works because brittle stone

fractures with pressurefractures with pressure Obsidian—natural glass material Obsidian—natural glass material

that forms sharp edgesthat forms sharp edges

MaterialsMaterials

SoftSoft MediumMedium HardHardSkinSkinGrassGrass

WoodWoodCartilageCartilage

BoneBoneShellShell

SEM and Light SEM and Light MicroscopesMicroscopes

Light microscope—reflects Light microscope—reflects and refracts lightand refracts light

-shows greater amount of objectshows greater amount of object

SEM—shoots electron SEM—shoots electron beamsbeams

-higher resolution and magnificationhigher resolution and magnification-Preparation may inhibit analysisPreparation may inhibit analysis

The ArchaeologyThe Archaeology

What Makes a Good Match?What Makes a Good Match?

Flake scarsFlake scars Edges: peaks, crevices, Edges: peaks, crevices, etc.etc.

Other: Striations, Pitting, etc. Other: Striations, Pitting, etc.

Meet the Meet the Artifacts!Artifacts!

Artifact 1Artifact 1

SEM x100SEM x100

Flake Scarring: 1 large Flake Scarring: 1 large flake scar and smaller flake scar and smaller irregular flake scars, irregular flake scars, shallow scarsshallow scars

Edges: deep crevices with Edges: deep crevices with rounded/dull fracture rounded/dull fracture peaks, shallow ridgespeaks, shallow ridges

Other: striationsOther: striations22

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Artifact 2Artifact 2

SEM x1000

Flake Scarring: shallow but Flake Scarring: shallow but well-defined flake scarswell-defined flake scars

Edges: jagged edges, Edges: jagged edges, rounded peaks between rounded peaks between flake scarsflake scars

Other: deep striations Other: deep striations radiating from flake scars, radiating from flake scars, some crumblingsome crumbling 33

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22

Artifact 3Artifact 3

SEM x500

Flake Scarring: shallow micro-Flake Scarring: shallow micro-scars (when magnified), scars (when magnified), extremely small, irregular extremely small, irregular distributiondistribution

Edge: irregular, jagged Edge: irregular, jagged damage, edges worn down damage, edges worn down with no distinct peakswith no distinct peaks

Other: percussion ripples, Other: percussion ripples, striationsstriations

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Meet the Meet the Replicas!Replicas!

Replica 1: WoodReplica 1: Wood

SEM x500SEM x500

Flake Scarring: micro-Flake Scarring: micro-scars visible only under scars visible only under SEMSEM

Edge: minor, irregular Edge: minor, irregular shallow chipping with shallow chipping with small, rounded peakssmall, rounded peaks

Other: frequent, irregular Other: frequent, irregular surface pittingsurface pitting

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22 33

Replica 2: Grass on Replica 2: Grass on GrindstoneGrindstone

SEM x2000

Flake Scarring: micro-Flake Scarring: micro-scars visible only under scars visible only under SEM SEM

Edges: rounded off dull Edges: rounded off dull edges without peaks edges without peaks

Other: noneOther: none33

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22

Replica 3: CartilageReplica 3: Cartilage

SEM x2000

SEM x360

Flake Scarring: well-defined Flake Scarring: well-defined flake scars, vary from wide flake scars, vary from wide and smooth to deep and and smooth to deep and narrownarrow

Edges: very deep crevices Edges: very deep crevices with steep fracture peaks, with steep fracture peaks, shallow jagged edge shallow jagged edge fractures with sharp peaksfractures with sharp peaks

Other: damage striationsOther: damage striations 33 44

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Replica 4: SkinReplica 4: Skin Flake Scarring: small, Flake Scarring: small,

shallow irregular flake shallow irregular flake scarsscars

Edges: jagged edges Edges: jagged edges sections with flattened sections with flattened peakspeaks

Other: surface pitting, Other: surface pitting, small striations, edge small striations, edge crumblingcrumbling

SEM x45

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Replica 5: BoneReplica 5: Bone

SEM x45

Flake Scarring: irregular, Flake Scarring: irregular, shallow flake scarsshallow flake scars

Edges: low jagged edges Edges: low jagged edges with rounded peakswith rounded peaks

Other: deep striationsOther: deep striations

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Replica 6: ShellReplica 6: Shell

SEM x2000

Flake Scarring: regular Flake Scarring: regular shallow flake scarsshallow flake scars

Edges: jagged peaks with Edges: jagged peaks with very deep ridges, rounded very deep ridges, rounded edges, irregular wearedges, irregular wear

Other: crumblingOther: crumbling33

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SEM SEM x100x100

Flake ScarsFlake ScarsComparisons IComparisons I

Replica 4 Replica 4 (Skin)(Skin)Artifact Artifact

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SEM SEM x45x45

Comparisons IIComparisons IIArtifact 2Artifact 2

Replica 3 Replica 3 (cartilage)(cartilage)

SEM x2000SEM x2000 SEM x2000SEM x2000

PeaksPeaks

Comparisons IIIComparisons III

Replica 5 Replica 5 (bone)(bone)Artifact 3Artifact 3

StriationsStriations

Thanks Thanks for for

Playing!Playing!

Experimental VariablesExperimental Variables-TechniqueTechnique-SuppliesSupplies-EnvironmeEnvironmentnt

Conclusions IConclusions IEvidenceEvidence ConclusionConclusion-Wood Wood pitting pitting-Cartilage Cartilage deep deep crevicescrevices-Etc.Etc.

-Different contact Different contact materials create materials create characteristic wear characteristic wear patterns on obsidianpatterns on obsidian

-Artifacts lack Artifacts lack intentional serrationintentional serration-Replicas did not Replicas did not require retouchingrequire retouching

-Retouching not Retouching not required to maintain required to maintain sharp edge on obsidian sharp edge on obsidian bladeblade

Conclusions IIConclusions IIEvidenceEvidence ConclusionConclusion-Comparisons of Comparisons of artifacts and replicasartifacts and replicas

-Nonmatches: grass, Nonmatches: grass, wood, shellwood, shell-Closest matches: skin, Closest matches: skin, cartilage, bonecartilage, bone

-Closest matches to Closest matches to skin, cartilage, and skin, cartilage, and bonebone

-Artifacts most likely Artifacts most likely used in some type of used in some type of butchering (range of butchering (range of animal material)animal material)

Conclusions IIIConclusions IIIEvidenceEvidence ConclusionConclusionObsidian blades are…Obsidian blades are…-RareRare-Acquired through Acquired through tradetrade-Not used intensivelyNot used intensively-Sacred material in Sacred material in other pre-Columbian other pre-Columbian culturescultures

-Blades not used for Blades not used for everyday butchering everyday butchering ritualistic functionritualistic function

Final ConclusionFinal Conclusion

RITUAL RITUAL SACRIFICESACRIFICE

Further experimentation requiredFurther experimentation required