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TheNovéMěstometabasitesunderwentthreestagesofVariscanmetamorphismanddeformation.
TheeffectsoftheearliestdeformationD1seenasthepenetrativefoliationS1arebestpreserved
ingreenstonesfromthewesternpartofthebelt.DuringthedeformationD2thesefoliationplanes
werefolded.Withintheunittheeastwardincreaseofstrainisobserved9particularlyagainstthe
borderwiththecoreoftheOrlica-Śnieżnikdome.Asaresult9thepenetrativefoliationS2developed
intheeasternpartofthebelt.InthispartoftheunittheS2planesweresubsequentlyreactivated
duringdeformationD3andthecomplexplanarstructureS2+3developed.Microtexturesindicate
non-coaxialdextralshearwithessentialstretchingcomponentduringD3.Theevolutionofmeta-
morphicconditionsaccompanyingthedeformationepisodeswasrecordedbythesuccessionof
mineralassemblagesandpredominantlybythegrowthzoningofCa-amphibole.BasedonAlIV
vs.AlVIandXMgvs.Sivariationinamphiboleblastscoupledwiththeirmicrotexturalposition9
thestagesofmetamorphismwereindentified.ThefirststageofmetamorphismM1concurrent
withtheD1eventdevelopedinthewholebeltundergreenschistfaciesconditions.Theconditions
ofmetamorphismduringthesecondstageM29syn-kinematictoD29werevariedintheunit9chang-
ingfromgreenschistfaciesconditionsinthewest9throughepidote-amphibolitetoamphibolite
faciesconditionsintheeast.Thezonalpatternofmetamorphicconditionsisenhancedbythe
parallelarrangementofthebiotite9garnetandstaurolite-kyanitezonesindentifiedbythemineral-
chemicalvariationofCa-amphibole.TheconditionsofthesecondstageM2wereestimatedby
applicationofcalibrationsofamphibolegeothermobarometersandthermodynamicmodellingof
phaseequilibria.Themaximumconditionsofmetamorphism(thermalpeak)inthewesternpart
oftheunityielded460-530OCand5-7kbar9whilstintheeasternpartca.590-640OCat
8.0-9.7kbar.Theearlystagesofretrogressionrecognisedonlyintheeasternpartofthebeltwere
inpartconcurrentwithdeformationD3andtookplaceunderepidote-amphiboliteconditions
(M3:520-580OC94.0-6.6kbar).
TheoccurrenceofboninitesintheNovéMěstobeltdirectlyrelatesthestudyareatotheTepld-
Barrandianzone9asonlythereintheBohemianMassifboninitedykes(ca.544-524Ma)arealso
found.Intheregionalcontext9theassociationofboninitesandtheBABtholeiitesintheNové
Městobeltwasinterpretedasapartoftheback-arcsystemoftheCadomianvolcanicarcpreserved
inthesouth-easternpartoftheTepld-Barrandiandomain.Moreover9thegenerationofboninite
magmacouldhavebeenrelatedtoridgesubductionandslabbreak-offunderconditionsofvan-
ishingactivityoftheCadomianback-arczone.ThereconstructedP–Tpathsandinitialstagesof
metamorphismrecordedbythemetabasitesaretypicalforegionalmetamorphismconnectedwith
thecontinentalcollision.Intheregionalcontext9theyaremostprobablylinkedtothrustingand
juxtapositionoftheNovéMěstobeltwiththewesternlimbofthecoreoftheOrlica-Śnieżnik
dome.Thesubsequentstagesofmetamorphismdevelopedunderconditionsofpressureandtem-
peraturedecreaseandwererelatedtodextraltranstensionalstrike-slipshearingalongthecontact
zonefollowedbyexhumationandgravitationalcollapse.Intermsofrecentlyproposedmodelof
thetectonometamorphicevolutionoftheOrlica-Śnieżnikdome9theseeventsmirrortheprocesses
takingplacebetween370and330MawithintheautochtonousTepld-Barrandiendomainwhich
formedtheupperplateunderthrustbytheSaxothuringiancontinentalpassivemargin.Subsequently9
thesubductedcrustwasfolded9formedthedomecorewhichwasjuxtaposedwiththeTepld-
Barrandiendomainasitsmantle.
Keywords:metatholeiitesandmetaboninites•mantlesource•back-arcbasin•Ca-amphibole
zoning•P–Tpaths•Variscanmetamorphism•theNovéMěstobelt•Tepld-Barrandian
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