A characterization and analysis of the floor plasters from the Acropolis at Copan, Honduras

512 Pages·1998·12.2 MB·English

by  McVey, Lorraine

UNIVERSITry
PENN5YLV^NL^
LIBRARIES

A CHARACTERIZATION AND ANALYSIS
OF THE FLOOR PLASTERS
FROM THE ACROPOLIS AT COPAN, HONDURAS
LorraineMcVey
ATHESIS
In
TheGraduateProgram in Historic Preservation in
PartialFulfillmentoftheRequirementsfortheDegree oftheMasterofScience
1998
L^^N^V-y-'Aj^
\
FrankG. Matero, GraduateGroupChairman and ProfessorofHistoric
Preservation,Advisor
U
\/iU(xJ
liAili, Doctoral CandidateYaleUniversity, Reader
UNIVtKollY
OF
PENNSYLVANIA
' LIBRARIES
ABSTRACT
AprogramofplasteranalysiswasinstitutedbytheEarlyClassic Acropolis
Programaspartofalargerstudyfocusedontheconstructionmethodsand materialsused
bytheMaya. Representative samplesoffloorplastersfromtheCopanAcropolis, the
centerofthesite'sarchitecturaldevelopmentduringtheClassicperiod(ca. AD420-800),
weresubmittedtotheArchitecturalConservationLaboratory(ACL)oftheUniversityof
Pennsylvania'sHistoricPreservationGraduateProgram foranalysis. Alaboratory
researchprogramwastodesignedtoinvestigatethestructureand compositionofthe
plasterscomprisedofahierarchical seriesofanalysis, includingarchival research, optical
microscopy,thinsectionpetrography, scanningelectronmicroscopywithenergy
dispersive spectroscopy(SEM-EDS), andX-raydiffraction(XRD).
The identificationofplasterconstituents,theirphysical characteristicsand
proportionswerethemost importantparametersofadiscerniblepatterninproduction
modesand materials selection. Themajorityofplastersampleswerecomposed ofalime
matrixandvariousaggregates, suchasthosederivedfromlimestone, volcanictuff, and
silicasand. Obtainingbindertoaggregateratioswasdifficultbytheconventional mortar
analysistechniquesused inthestudysincethe matrixandpartialaggregratefractionboth
werecalcareous materials.
Aggregateparticle sizes, shapesandproportionschanged overtimebut withouta
distinguishableevolution. Oneexceptionwasareduction intheamount ofcarbonvisible
intheplasters fromthelastconstructionphase, suggestingachangeineitherproduction
techniquesormaterialsavailableforlimeproduction. Overall, theplastersappearedto

haveacompact limematrixdevoid ofcracks, and included awell balanced distribution
ofparticlestoindicatetheMayahadanempirical knowledgeofthecriticalproperties
requiredfordurableplasters.