Archaeometric prospection using electricalusing electrical

Joint Meeting 2009-GP10-829

Archaeometric prospection using electrical survey predictiveusing electrical survey predictive

deconvolution (ESPD)(ESPD)

Paul GloverUniversité Laval Québec CanadaUniversité Laval, Québec, Canada

PlanPlan

Introduction – The past revisited!Plan

Introduction

Wh t i

Introduction – The past revisited!What is a Grubenhaus?Wh i th h ?What is a

Grubenhaus?

Where is thesearch area?

Where is the search area?How? – Experimental Methodology

How? –ExperimentalMethodology

How? –

How? – Data Analysis – Predictivedeconvolution

Data Analysis

Results

Conclusions

ResultsConclusions

Who? –Acknowledg-

mentsWho? – Acknowledgments

GrubenhäuserSmall sizedExcavated floorsli d ith l kPlan

Introduction

Wh t i

lined with planks orpacked clayMultiple use –What is a

Grubenhaus?


Multiple use –workshops rather than dwellings


How? –

PotteryWeavingMetal-workingAnimalData Analysis

Results

Conclusions

Animal husbandry…etc.

Usually found in Who? –

Acknowledg-ments Typical excavated Grubenhäuser

from 3 UK sites (Glover, 1985)

association with timber-framed halls

Grubenhäuser

Plan

Introduction

Wh t iWhat is a Grubenhaus?



How? –Data Analysis

Results

Conclusions

Who? –Acknowledg-

ments Line drawing of the New Bewick Grubenhaus

Grubenhäuser

Plan

Introduction





Results

ConclusionsReconstruction of the New Bewick Grubenhaushttp://www.bedesworld.co.uk/site_2003-05-10/building/nbkdescr.htm

Who? –Acknowledg-

ments

GeneralLocation

Plan

Introduction

Wh t i

200 m fromRiver Breamish

El ti 94What is a Grubenhaus?


Elevation 94 m

1.8 km from OldBewick Iron Age


How? –

gHillfort (rock art)

16 km from MilfieldData Analysis

Results

Conclusions

MilfieldYeaveringThirlings

Anglo-Saxon royal/Who? –

Acknowledg-ments

Palace settlements

GeneralLocation

Plan

Introduction





Results

Conclusions

Light grey area representsThe survey area (in two parts)

Who? –Acknowledg-

ments

Dark grey area represents thesubsequently excavated area

AerialPh t hPhotography

Plan

Introduction

Wh t i

Marks include

TramlinesWhat is a

Grubenhaus?


Drainage

Glacial TillHow? –

ExperimentalMethodology

How? –

Frost Cracking

Old Hedge

N

Data Analysis

Results

Conclusions

Old Hedge Boundaries

ArchaeologicalWho? –

Acknowledg-ments

Remains

AerialPh t hPhotography

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

mentsAerial Photography

Methodology

Plan

Introduction




How? –ABEM Mk II T t & i h tData Analysis

Results

Conclusions

ABEM Mk II Terrameter & in-house meter

33 electrodes multiplexed into 4

Survey area 10140 m2

Who? –Acknowledg-

ments

May and June, dry weather with short winter wheat

Light, sandy topsoil

Raw dataRaw data

Plan

Introduction

Wh t i

Raw data fromthe first part ofthe survey areaWhat is a

Grubenhaus?


the survey area



Results

Conclusions

Who? –Acknowledg-

ments

Data AnalysisData Analysis

Plan

Introduction

Wh t i

Each structure has an electrical signature orsource functionPredictive deconvolution need to predict theWhat is a

Grubenhaus?


Predictive deconvolution – need to predict thesource functionSource function can be calculated uniquely


How? –

Source function can be calculated uniquelyfrom a geometrical model of the subsurfacefeature

Data Analysis

Results

Conclusions

The model, however, is not uniqueThe method restores the target structure…

but destroys structures of other geometriesWho? –

Acknowledg-ments

…but destroys structures of other geometriesAnalysis carried out by matrix inversion

Data Analysis: Th S F iThe Source Function

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Convolution:SyntheticSynthetic

Data

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Deconvolution:Restoration of

location

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Deconvolution:Restoration of l ti dlocation and

extent

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Data Analysis – Test 1Restoration of location

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Data Analysis – Test 2Restoration of location and extent

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Results - Undeconvolved

CDitch II Packed earth

Plan

Introduction

Wh t i

D

C

B

Results

UndeconvolvedWhat is a

Grubenhaus?


BDeconvolved

3 m width

DeconvolvedHow? –


How? – A

Ditch IDeconvolved

4 m width

Deconvolved5 m width

Data Analysis

Results

Conclusions FE

5 m width

CombinedData

Who? –Acknowledg-

ments

E

Results – DeconvolvedSource function 3 m wideSource function 3 m wide

Plan

Introduction

Wh t i

Results


Grubenhaus?



DeconvolvedHow? –


How? –



Data Analysis

Results

Conclusions

5 m width

CombinedData

Who? –Acknowledg-

ments


Plan

Introduction

Wh t i

Results


Grubenhaus?



DeconvolvedHow? –


How? –



Data Analysis

Results

Conclusions

5 m width

CombinedData

Who? –Acknowledg-

ments


Plan

Introduction

Wh t i

Results


Grubenhaus?



DeconvolvedHow? –


How? –



Data Analysis

Results

Conclusions

5 m width

CombinedData

Who? –Acknowledg-

ments

Results -Combined

View

Plan

Introduction





Results

Conclusions

Who? –Acknowledg-

ments

Proof by Excavationy(Gates and O’Brien, 1988)

Deconvolved survey

Plan

Introduction




How? – (in metres) Survey ExcavatedData Analysis

Results

Conclusions

(in metres) Survey Excavated

Width 4 3.9Length 5 4.7

Depth 0.6 0.5Who? –

Acknowledg-ments

pTopsoil (0.3) 0.3

Gates and O’Brien, 1988

ConclusionsConclusions

C l l t i l d t bPlan

Introduction

Wh t i

Complex electrical survey data can bedeconvolved to provide the location andextent of buried features IF their source

What is a Grubenhaus?


signature can be predictedElectrical survey at New Bewick predicts the

f t l t 6 b häHow? –ExperimentalMethodology

How? –

presence of at least 6 grubenhäuserOne of the predicted grubenhäuser has beenexcavated and confirmed with the sameData Analysis

Results

Conclusions

excavated and confirmed with the samedimensions as the survey predictedThe site shows other features, and may be the

Who? –Acknowledg-

ments

ysite of a significant settlement (timber-framed halls?)

AcknowledgmentsAcknowledgments

Plan

Introduction

Wh t i

Mr. J Clark – New Bewick Farm

P. Clark & T. Gates - Newcastle Archaeological UnitWhat is a

Grubenhaus?


Prof. Norman McCord – Aerial photography



Results

Conclusions

Who? –Acknowledg-

ments

Documents

Archaeometric prospection using electricalusing electrical