Late Cretaceous to Recent kinematics of SE Anatolia (Turkey)

28 Pages·2010·2.51 MB·English

Geological Society, London, Special Publications

Late Cretaceous to Recent kinematics of SE Anatolia (Turkey)

N. Kaymakci, M. Inceöz, P. Ertepinar and A. Koç

Geological Society, London, Special Publications 2010; v. 340; p. 409-435
doi:10.1144/SP340.18
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Notes
Downloaded by Middle East Technical University on 16 September 2010
© 2010 Geological Society of
London
Late Cretaceous to Recent kinematics of SE Anatolia (Turkey)
N.KAYMAKCI1*,M.INCEO¨Z2,P.ERTEPINAR3&A.KOC¸1
1MiddleEastTechnicalUniversity,DepartmentofGeologicalEngineering,
06531-Ankara,Turkey
2FıratU¨niversitesiMu¨hendislikFaku¨ltesiJeolojiMu¨hendislig˘iBo¨lu¨mu¨,23119Elazıg˘,Turkey
3ForthoofddijkPaleomagneticLab.DepartmentofEarthSciences,UtrechtUniversity,
Budapestlaan17,3584CDUtrecht,theNetherlands
*Correspondingauthor(e-mail:[email protected])
Abstract: FivedifferentdeformationphaseshavebeenrecognizedintheSEAnatolianorogenand
theArabianPlatformbasedonpalaeostressinversionstudiesusingfault-slipdatasets.Thetiming
anddurationofthesephasesaredeterminedusingvariouscriteriaincludingtheageoftheaffected
strata, syndepositional structures, cross-cutting structures and overprinting slickensides. The
oldestdeformationphaseischaracterizedgenerallybyNE–SW-directedextension.Theextension
is thought to have resulted from slab-roll back processes during the Maastrichtian to Middle
Eocene interval (c. 60Ma to 40–35Ma). The second deformation phase is characterized
byeast–westtoNW–SE-directedcompressionandthoughttoresultfromcessationofroll-back
processespossiblydue tosubduction of youngeroceanic crust or increase in the convergence
rate between Africa and Eurasia during the post-Middle Eocene to Late Oligocene interval
(c. 40–35Ma to 25Ma). The third deformation phase is characterized by east–west to
NW–SE-directedextensionpossiblyduetoslabdetachmentthatinitiatedinIranandmigrated
westwardsduringthelatestOligocenetoMiddleMioceneperiod(25–11Ma).Thefourthdefor-
mationphaseischaracterizedbyapproximatelynorth–south-directedcompressionduetocollision
andfurthernorthwardsindentationofArabianPlatebytheendofMiddleMiocene(11–3.5Ma).
ThefifthandpresentdeformationphaseischaracterizedbyNE–SWcompressionwhichmight
resultfromtectonicre-organizationintheregionsincetheMiddlePliocene(c.3.5Matorecent).
TheLateCretaceoustorecenttectonicdevelopment thrusting,ophioliticnappeemplacementandwhole-
of SE Turkey is related to the closure of the sale metamorphism of the KMBB and northern
Neotethys Ocean along two trenches namely the marginoftheTaurides.Thesemetamorphicmassifs
southernandnorthernbranches(S¸engo¨r&Yılmaz whichbelongtothenorthernmarginoftheTaurides
1981) while the evolution of these subduction are also known as Anatolides (Ketin 1966). The
systems partly overlapped in space and time. The closure of the southern branch took place along
Izmir-Ankara-ErzincanSutureZone(Fig.1)marks the Bitlis–Zagros Suture Zone during the Middle
the former position of the northern branch of the Miocene (S¸engo¨r et al. 1985; Yig˘itbas¸ & Yılmaz
Neotethys which separated the Pontides (Eurasian 1996a,b;Huesingetal.2009;Kus¸cuetal.2010).
affinity) in the north and the Taurides (Gondwana However, some argued that its closure took place
affinity)inthesouth.IneasternTurkey,theTaurides intheLateCretaceousandtheNeogenedeformation
arerepresentedbytheKeban-Malatya-BitlisBlock is related to post-collisional convergence (e.g.
(KMBB). The Bitlis–Zagros Suture Zone marks Yazgan&Sussex1991;Bayarslan&Bingo¨l2000).
the former position of the Southern Neotethys. Two contrasting styles of thrusting and nappe
DuringtheMesozoictopre-LateMiocene,itsepar- emplacement define the current structural archi-
atedtheTauridesfromtheAfrican–ArabianPlate. tecture of eastern and south-eastern Anatolia in
There is still an ongoing debate on the exact addition to a number of generally NE–SW to
locationandtimingofclosureofthesetwooceanic NNE–SSW striking strike–slip faults (Fig. 2).
domains.Nevertheless,itisgenerallyacceptedthat These are generally south-verging thrust faults
theclosureofthenorthernbranchtookplace,along along which much of the ophiolitic masses and
theI˙zmir-Ankara-ErzincanSutureZone,attheend slivers belongingto the northern Neotethys Ocean
of the Late Cretaceous (Tu¨ysu¨z 1999; Kaymakcı were emplaced onto the KMBB during the
et al. 2003, 2009) to Early Cenozoic (S¸engo¨r & Campanian–Maastrichtian (Perinc¸ek & O¨zkaya
Yılmaz 1981; Go¨ru¨r et al. 1984; Robertson et al. 1981). Other important structures are the north-
2005) and gave way to a widespread southwards verging thrust faults related to the successive
From:Sosson,M.,Kaymakci,N.,Stephenson,R.A.,Bergerat,F.&Starostenko,V.(eds)SedimentaryBasin
TectonicsfromtheBlackSeaandCaucasustotheArabianPlatform.GeologicalSociety,London,SpecialPublications,
340,409–435. DOI:10.1144/SP340.18 0305-8719/10/$15.00#TheGeologicalSocietyofLondon2010.
410 N.KAYMAKCIETAL.
Fig.1. RegionaltectonicunitsaroundTurkey(modifiedfromOkayetal.1994;Stampfli&Borel2002).Notethat
Menderes,Kırs¸ehir,Alanya,Keban-MalatyaandBitlisunitsarealsoknownasAnatolides(Ketin1966)whicharethe
metamorphosedequivalentsofTaurides(S¸engo¨r&Yılmaz1981).NotealsothatSakarya-Tokat-Kargı,Agvanis-Pulur
massifsarepartofRhodope-PontideFragments.TheBaskil,MadenandUrimeh-DoktarbeltsbelongstoLate
CretaceoustoEocenearcandbackarcsettingsofBitlis–ZagrosSuturezone.
collision of an island arc chain (Afs¸in-Baskil arc) branch of the Neotethys (e.g. Yig˘itbas¸ & Yılmaz
during the Late Cretaceous, located between the 1996a, b; Robertson 2002; Parlak 2004; Parlak
KMBB and the Arabian Block (Figs 1 & 2c), et al. 2004, 2006; Robertson et al. 2005; Faccena
withinthesouthernbranchoftheNeotethys. etal.2005;Kus¸cuetal.2010).
Terminal collision of the Arabian Plate produ- The active tectonic scheme of the region is
ced approximately north–NE-striking transcurrent related to (1) the detachment of the subducting
faults which translated Late Miocene to Middle oceanic lithosphere at the northern end of the
Pliocenethrustfaultsmorethan100kmalongtheir Arabian plate; (2) development of a Subduction
strike. Due to bivergent thrusting, which is due Transform Extension Propagator (STEP) fault (cf.
southinthesouthandduenorthinthenorth,gave Govers & Wortel 2005) along the northwestern
way to pop-up-like uplift of the KMBB during marginoftheArabianPlate(Facennaetal.2005);
the Late Miocene to Middle Pliocene (Fig. 2c). and (3) collision and further northwards conver-
The recent studies indicated that the evolution of genceoftheArabianPlatebytheendoftheMiddle
the region is rather complex. Various ophiolitic Miocene (c. 11Ma) (S¸engo¨r et al. 1985; Dewey
and magmatic units in the region are originated et al. 1986; Huesing et al. 2009). These processes
fromdifferenttectono-magmaticsettingsincluding gave way to inversion of most of the pre-existing
processes possibly related to slab roll-back, slab structuresanddevelopmentofanumberofNNE–
detachment,supra-subductionzoneophiolitegener- SSW to ENE–WSW striking strike–slip fault
ationduringthenorthwardssubductionofsouthern systems(Perinc¸eket al.1987;Westaway & Arger
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Fig.2. (a)OutlineactivetectonicsofTurkey.(b)Majorpalaeotectonic(red)andneotectonic(black)structuresandCenozoicbasinsincentralandsoutheasternTurkey.
(c)Simplifiedregionalcross-sectionalongthelineXY.
412 N.KAYMAKCIETAL.
2001; Kaymakcı et al. 2006) in response to STEP and clastics deposited during the Cenozoic
faulting,north–southshortening,crustalthickening (Figs2–4).
(Dewey et al. 1986) and westwards escape of the
AnatolianBlock(S¸engo¨retal.1985). StratigraphyoftheArabianPlatform
The aim of this study is to present Late Creta-
ceoustorecentkinematicevolutionofSEAnatolian The Arabian Platform comprises sedimentary
Orogen and the northwestern part of the Arabian successions ranging from Precambrian to Recent
Platforminordertoconstrainthetiming,mechan- (Fig.3).Itisgenerallyacceptedthatitwaslocated
ism and extend of processes related to subduction at the northern margin of the Gondwana from the
ofthesouthernNeotethysOceanandcollisionand Precambrian to the Late Palaeozoic. The Arabian
further northwards convergence of Arabian Plate. Platform constituted the southern passive margin
The SE Anatolian Orogen, here, refers to the area of the Southern Neotethys Ocean after rifting and
north of the Bitlis–Zagros Suture and south of northwardsdriftingoftheTauridesfromitsnorthern
Izmir-Ankara-Erzincan Suture Zone in Turkey marginduringtheMesozoictoPalaeogene(S¸engo¨r
(Yılmaz1993). &Yılmaz1981).
The oldest compressional structures on the
Tectono-stratigraphy platformarerelatedtotheemplacementofophioli-
tic units during the Campanian to Maastrichtian
The tectonic units that played a role in the dev- (Perinc¸ek & O¨zkaya 1981). These structures and
elopment of the region include the Arabian thrustcontactsaresealedbytheLateMaastrichtian
Platform, Bitlis Massif, Keban-Malatya Platform, to Paleocene and younger units. The important
non-metamorphosed Tauride Platform units, and youngeststructuresthatshapethepresentstructural
various ophiolitic and magmatic complexes com- grain of the platform are related to the late
prising Afs¸in-Baskil arc and Maden complex Miocene collision and preceding foreland basin
(Figs1&2).Theseunitsaretectonicallyimbricated development. In this study, we concentrated
alongnorthdippingthrustfaultsandareunconform- mainlyonthepost-Maastrichtiankinematicevents
ably overlain by marine to continental carbonates withintheplatform.
Fig.3. GeneralizedCretaceoustoRecenttectonostratigraphicalcolumnofArabianPlatforminTurkey(modified
fromPerinc¸ek&O¨zkaya1981;Yılmaz1993).Absoluteagescorrespondtothebeginningofdeformationphases
mentionedinthetext.
KINEMATICSOFSEANATOLIA(TURKEY) 413
Fig.4. GeneralizedMaastrichtiantoRecenttectono-stratigraphicalcolumnofSEAnatolianorogen(modifiedfrom
Yig˘itbas¸&Yılmaz1996a).
The sampled interval on the Arabian Platform Arabian Platform. The Paleocene association is
ranges in age from Maastrichtian to Pliocene and unconformably overlain by Eocene to Lower
includes a facies association, from bottom to top, Miocene rock units. The Eocene to Lower
few tens of metres thick continental red clastics Miocene units have very rapid lateral and vertical
(Terbu¨zek Formation), chalky marls (Besni For- facies changes in different parts of the Arabian
mation),aturbiditicsequence(GermavFormation) Platform.Therefore,intheliterature,variouslocal
composed of alternation of sandstone, siltstone names are used for these units. For simplicity
and shale. These facies are overlain by clastics we followed the nomenclature of Sungurlu (1974)
(Gercu¨s¸ Formation) and about ten metres thick and Perinc¸ek (1979) who collectively named the
neritic limestone (Becirman Formation) (Yılmaz Eocene clastic sequence as the Gercu¨s¸ Formation
1993). These units are unconformably overlying andoverlyingcarbonatesastheMidyatLimestone.
theolderunitsandsealsthethrustcontactbetween The Eocene clastic sequence (Gercu¨s¸ Formation)
thelateCretaceousemplacedophioliticmelanges. iscomposedofvariousclasticsincludingconglom-
The thickness of the turbidites (Germav For- erates, sandstones and mudstones gradually fining
mation) increases northwards as the grain sizes upwards as the depositional environments are
become coarser and comprises olistostrommal changing from continental to marine settings. The
conglomerate lenses. In the southwestern part of overlyingcarbonates(MidyatLimestone)comprise
thestudyarea,thePaleocenerocksunconformably threedistinctlevels.Thelowerleveliscomposedof
overlies the ophiolitic units (Karadut & Koc¸ali dolomiticlimestonesthatgraduallygradeintolime-
complexes) which indicates that these units are stones with cherty intervals and limestones with
deposited after the Campanian–Maastrichtian cherty nodules. These levels are also known as
emplacement of the ophiolitic units onto the Gaziantep Formation (Wilson & Krummenacher
414 N.KAYMAKCIETAL.
1957). The cherty levels upwards grade into the contemporarysedimentarysequenceswerestudied
medium- to thick-bedded marl, chalky limestone indetail(Fig.4).
alternations with occasional cherty nodules. This TheMaastrichtiantoPaleocenesequenceshave
uppermost chalky limestone part of the Midyat lateral and vertical facies changes ranging from
Formation is also named as Fırat Formation along turbidites (Gu¨rer & Aldanmaz 2002) to pelagic
thenorthernedgeoftheArabianPlateandisearly limestonestoshallowcontinentalredclastics(Aziz
to Middle Miocene in age (Perinc¸ek 1979). The et al. 1982; Perincek & Kozlu 1984). Around the
Fırat Formation also comprises tuff layers in its Darende Basin (Fig. 2b), at the bottom, these
lower parts and grades northwards laterally into sequences rest on ophiolitic units with an uncon-
turbidites (Lice Formation) (Tuna 1973; Sungurlu formityandarecomposedofturbiditicfaciescom-
1974;Perinc¸ek1979;Perinc¸ek&O¨zkaya1981). prising conglomerate, sandstone, siltstone and
TheLowertoMiddleMioceneTurbidites(Lice shale alternationswhichgradesupwardsintoshal-
Formation, Tuna 1973) comprises northwards and low marine limestones. In the southern margin of
upwardscoarseningturbiditefacies.Itisdeveloped theMalatyaBasin,theseunitsareMaastrichtianin
mainlyinfrontofthesouth-directedthrustfaultsat ageandarecomposedofalternationofpelagiclime-
thenorthernedgeoftheArabianPlatformalongthe stonesandmarlsintercalatedwiththinsandstones.
leadingedgeoftheBitlis–ZagrosSuture.Itisgen- The Upper Maastrichtian sequences are un-
erally accepted that these turbidites (Lice For- conformablyoverlainbytheUpperPaleocenecon-
mation) mark the terminal stage of subduction of tinental red clastics comprising red to purple
theSouthernBranchoftheNeotethysandbeginning conglomeratesandsandstonesequences.Thelower
ofcollisionoftheArabianPlate(S¸engo¨r&Yılmaz part of the Upper Paleocene sequence is always
1981). They are conformably overlain by cont- associated with normal growth faults (Fig. 5). In
inentalredclasticswhichareknownalsoasS¸elmo the southern margin of the Malatya Basin, this
(Perinc¸ek 1979) and Adıyaman (Tuna 1973) sequence is about 100m thick and rapidly grades
formations (Fig. 3) in the northeastern and north- into boulder conglomerates and sandstones which
westernpartsoftheArabianPlatformrespectively. subsequently grades upwards into turbiditic facies
A very widespread isolated alkaline basaltic alternating with nummulites bearing limestone
lavaflowsareemplacedontotheArabianPlatform. horizons. This sequence is overlain by Oligocene
These basaltic lava flows can be subdivided into shallow marine limestones only to the western
three distinct groups. The oldest lava flows are marginoftheMalatyaBasin.However,withinand
observed around the western margin of the intheeasternmarginoftheMalatyaBasin,Oligo-
Arabian Platform and have lateral gradations cene sequences are missing. Inthese areas, Lower
withthe FıratFormation.The K–Aragesofthese Miocenesequencesdirectlyresteitheronthemeta-
volcanic rocks range between 21.24+2.04 to morphicbasementorontotheEocenesequences.
9.22+0.2Ma(Yoldemir1987;Tataretal.2004). TheLowerMiocenesequencesstartatthebottom
The second group is exposed in the central part with few metres thick shallow marine shales
of the Arabian Platform and are unconformably and marls which continues upwards with few tens
overlying the Fırat Formation and their K–Ar of metres thick condensed sequence of shallow
agesrangebetween 12.1+0.4to 7.02+0.07Ma marinealgallimestones.Thecondensedsequences
(Yoldermir 1987; Ulu et al. 1991). The third are conformably overlain by Middle Miocene
andyoungestgroupbelongstotheKaracadag˘ Vol- lacustrine facies in the Malatya and Gu¨ru¨n basins
canic Complex and their K–Ar ages range (Figs 2 & 4). The lacustrine sequences grade
between0.94+0.33to 0.83+0.88 (Pearceetal. upwards into fluvio-lacustrine clastics intercalated
1990). withcoalseamsandintoavolcano-clasticsequence
in the northern part of the Malatya Basin. Based
onrodentfauna(Kaymakcıetal.2006)and15.2–
StratigraphyoftheSEAnatolianorogen 15.9Ma (Arger et al. 2000) K–Ar ages from the
inter-layered lava flows these sequences are of
The sampled intervals within the SE Anatolian Middle to Late Miocene in age. In the Kangal
orogen range in age from Maastrichtian to Early Basin (Fig. 2), deposition of these sequences con-
Quaternary.TheEocenevolcanicandvolcaniclastic tinueduntiltheEarlyPliocene.Allthesesequences
rocks of the Maden Complex were not studied for areunconformablyoverlainbytheUpperPliocene
palaeostress analysis. The reason for this is toPleistocenefluvialclastics.
because,inthevolcanicfieldslocalstressvariations
areunpredictableandtheyreflectlocalstressfields Palaeostressinversion
rather than regional stress configurations due to
rapiddepositionandextensivelocalverticalmove- Palaeostress analysis aims at the reconstruction of
ments during volcanic eruptions. However, palaeostress configurations using fault-slip data
KINEMATICSOFSEANATOLIA(TURKEY) 415
Fig.5. GrowthfaultsdevelopedwithinthePaleoceneclastics(location:Site28inFig.6,viewtoNE)andtheir
palaeostressconfiguration.Notethatnorth–southextensionofthegrowthfaults.
sets(Angelier1994).Thebackboneofthemethod shearstressalongapre-existingplaneofweakness.
is based on the assumption that the slip occurs Therefore,maximumresolvedshearstressdirection
parallel to the maximum resolved shear stress correspondstotheslipdirectionwhichismanifested
along an optimally orientated plane of weakness ontheplaneasslickenlines(Angelier1994).During
(Wallace 1953; Bott 1959). Basically, there are theconstructionofthepalaeostressconfigurations,
two types of palaeostress inversion techniques. the maximum shear stress direction is determined
The graphical approaches generally based on by calculating the axes of the stress ellipsoid by
Anderson’s (1951) fault theory which states that using the shape factor (f¼s 2s/s 2s). In
2 3 1 3
the maximum principal stress is the acute-bisetrix whichs,s ands correspondtomaximum,inter-
1 2 3
of conjugate fault sets while minor stress is the mediate and minor principal stress magnitudes,
obtuse-bisetrix and intermediate stress is parallel respectively.
to the intersection of conjugate fault planes. This Inthisstudy,wehaveappliedonlythenumerical
approach is based on the fact that the earth’s methoddevelopedbyAngelier(1988).Themethod
surface is one of the principal planes so that one isbasedonthecalculationofareducedstresstensor
ofthestressesisalwaysvertical.Thisimpliesthat whichmeansthattherelativemagnitudesandorien-
oblique-slip faults are always re-activated planes tations of the principal stresses are determined by
of weaknesses. In this approach, the most reliable using the shape factor and orientation of at least
resultscanonlybeobtainedinthecaseofconjugate four fault slip data belonging to the same defor-
faultswhichare,mostofthetime,verydifficultto mationphase(seeAngelier1994forafullaccount
determine during field studies. On the other hand, ofthemethod).
the numerical methods are based mainly on the Inadditiontodirectionandmagnitudes,oneof
reconstruction of the stress ellipsoid by using the the other key issues in palaeostress analysis is the
Wallace (1953)–Bott (1959) assumption. In this dating of the constructed stress configurations.
approachslip occurs along the maximumresolved Thisisaccomplishedbyusingvariouscriteriathat
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Fig.6. Majorfaultsandsamplelocationsofthestudyarea.FaultnamesareasinFigure2.
KINEMATICSOFSEANATOLIA(TURKEY) 417
Fig.7. PalaeostressconfigurationsbelongingtoPaleocenetoMiddleEoceneextension(phase1).Notethatsites
91–107belongtotheArabianPlatform,allothersbelongtoSEAnatolianorogen.Equalarea,lowerhemisphere
projection.
include,indecreasingorderofreliability,synsedi- discernable),anyincompatiblecompressionalstruc-
mentary structures and faults, the age of the ture overprinted or displaced by an extensional
youngest faulted strata and age of the oldest structure (or vice versa), overprinting kinematic
sealing strata, age of the youngest sequences dis- indicators within the same fault plane, and over-
placedbyaspecificfaultorfaultsets(ifnosealis printingslickensides(Kaymakcıetal.2000).