The Palu-Uluova Strike-Slip Basin in the East Anatolian Fault System, Turkey

24 Pages·2012·12.11 MB·English

Turkish Journal of Earth Sciences (Turkish J. Earth Sci.), VSo.l .Ç 2O1,L 2A0K12 E, Tpp A. L54.7–570. Copyright ©TÜBİTAK
doi:10.3906/yer-1002-14 First published online 16 August 2011
Th e Palu-Uluova Strike-Slip Basin in the

East Anatolian Fault System, Turkey: Its Transition
from the Palaeotectonic to Neotectonic Stage
SERAP ÇOLAK1, ERCAN AKSOY1, ALİ KOÇYİĞİT2 & MURAT İNCEÖZ1

1
Fırat University, Deparment of Geological Engineering, TR–23119 Elazığ, Turkey
(E-mail: eaksoy@fi rat.edu.tr)
2
Middle East Technical University, Department of Geological Engineering,
Active Tectonics and Earthquake Research Laboratory, Üniversiteler Mahallesi, Dumplupınar Bulvarı,
TR–06800Ankara, Turkey
Received 16 February 2010; revised typescripts received 19 June 2010, 17 January 2011 & 16 June 2011;
accepted 08 July 2011
Abstract: Th e East Anatolian fault system (EAFS) is the 80-km-wide, 700-km-long, NE-trending sinistral strike-slip
fault system forming a seismically very active intracontinental transfom fault boundary. It is located between Karlıova
County in the northeast and Karataş-Samandağ counties in the southwest, and forms the southeastern boundary of the
Anatolian platelet. Th e Palu-Uluova basin is one of several strike-slip basins located along the EAFS. It is surrounded by
several push-ups such as the Karaömerdağı, Mastardağı and Askerdağı push-ups caused by the complexities peculiar to
strike-slip faulting. Th e Palu-Uluova basin consists of three sub-sections: two are NE-trending strike-slip sub-basins, the
Uluova and the Palu-Kumyazı sub-basins, while the third is a ramp basin, the E–W-trending Yolüstü basin which links
the earlier two sub-basins. Th e Palu-Uluova basin is characterized and shaped by a 130-m-thick neotectonic basin infi ll
(Palu Formation) and a series of bounding strike-slip fault zones such as the Sivrice, Adıyaman, Uluova, Elazığ, Pertek
and Yolüstü fault zones. Th e Palu Formation is an undeformed fl uvio-lacustrine sedimentary sequence. Th e youngest
palaeotectonic rock-stratigraphic unit is the Upper Miocene–Lower Pliocene Çaybağı Formation, deposited in a ramp
type of intermontane basin bounded and controlled by the reverse faults. Th e Çaybağı Formation is intensely deformed
(steeply tilted, folded and thrust to reverse-faulted) on a regional (mappable) scale. Th e compressional deformation
pattern of the Çaybağı Formation is truncated, sealed and overlain with angular unconformity by the nearly horizontal
undeformed Plio–Quaternary Palu Formation. Th is regional angular unconformity refl ects: (a) a series of pre-Late
Pliocene regional tectonic inversions (e.g., type of the tectonic regime, style of deformation and nature of magmatic
activity), and (b) the timing of the major transition from the folding and thrust to reverse faulting-dominated
palaeotectonic period into the strike-slip faulting-dominated neotectonic period is Late Pliocene.
Key Words: East Anatolian fault system, Palu-Uluova strike-slip basin, intermontane basin, Turkey
Doğu Anadolu Fay Sistemi Üzerindeki Palu-Uluova Doğrultu Atımlı Fay Havzası,
Türkiye: Paleotektonik Dönemden Neotektonik Döneme Geçiş
Özet: Doğu Anadolu Fay Sistemi (DAFS) 80 km genişlikte, 700 km uzunlukta, KD-gidişli, sismik bakımdan çok etkin,
sol yanal doğrultu atımlı ve kıta içi dönüşüm türü fay niteliğinde bir plaka sınırıdır. DAFS kuzeydoğuda Karlıova ile
güneybatıda Karataş-Samandağ ilçeleri arasında yeralır ve Anadolu plakacığının güneydoğu sınırını oluşturur. DAFS
üzerinde çok sayıda doğrultu atımlı havza yer alır. Bunlardan biri Palu-Uluova doğrultu atımlı fay havzasıdır. Palu-
Uluova havzası, doğrultu atımlı faylanmalara özgü karmaşıklıklardan kaynaklanmış Karaömerdağı, Mastardağı ve
Askerdağı gibi bazı bindirme (ters faylanma) yükselimleriyle çevrelenir. Palu-Uluova havzası üç alt bölümden oluşur.
Bunlardan ikisi KD-gidişli doğrultu atımlı alt havza, üçüncüsü ise, D–B gidişli bir dağarası havza olup ilk iki alt havzayı
birbirine bağlar. Bunlar sırayla KD-gidişli Uluova, Palu-Kumyazı ve Yolüstü alt havzalarıdır. Palu-Uluova havzası 130 m
kalınlıkta neotektonik bir havza dolgusu (Palu Formasyonu) ve bir seri kenar fay zonu ile karakterize edilir ve şekillenir.
Önemli kenar fay zonları Adıyaman, Sivrice, Uluova, Elazığ, Pertek ve Yolüstü fay zonlarıdır. Neotektonik havza
dolgusu Palu Formasyonu ile temsil edilir. Palu Formasyonu deformasyon geçirmemiş (yatay konumlu) bir göl-akarsu
sedimanter istifinden oluşur. En genç paleotektonik birim Geç Miyosen–Erken Pliyosen yaşlı Çaybağı Formasyonu’dur.
Çaybağı Formasyonu ters faylarla sınırlanıp denetlenmiş bir dağarası havzada çökelmiştir. Çaybağı Formasyonu bölgesel
ölçekte (haritalanabilir) ve yeğince deformasyon geçirmiştir (dikçe eğimlenmiş, kıvrımlanmış ve ters faylanmıştır).
Çaybağı Formasyonu’nun sıkışmaya bağlı deformasyon biçimi, Pliyo–Kuvaterner yaşlı ve deformasyon geçirmemiş
547
PALU-ULUOVA BASIN IN THE EAST ANATOLIAN FAULT SYSTEM
olan Palu Formasyonu tarafından yer yer üstten aşındırılarak kesilmiş ve açılı bir uyumsuzlukla örtülmüştür. İki
formasyon arasındaki bölgesel ölçekli bu açılı uyumsuzluk, aşağıdaki sonuçları yansıtmaktadır: (a) Geç Pliyosen öncesi
gerçekleşmiş bir seri tektonik dönüşümü ( örneğin: tektonik rejimin türü, deformasyon biçimi ve magmatik etkinliğin
karakterindeki değişme gibi), (b) kıvrımlanma ve bindirme faylarıyla karakterize edilen paleotektonik dönemden,
doğrultu atımlı faylanma ile karakterize edeilen neotektonik döneme geçişin Geç Pliyosen’de gerçekleştiği, başka bir
deyişle neotektonik dönemin başlangıç yaşının Geç Pliyosen olduğunu yansıtmaktadır.
Anahtar Sözcükler: Doğu Anadolu fay sistemi, Palu-Uluova doğrultu atımlı fay havzası, dağarası havza, Türkiye
Introduction seems to be a more plausible explanation for the
formation of both the Anatolian platelet and its
One of the best-known intracontinental transform
boundary fault systems (NAFS and EAFS), the time
fault systems is the NE-trending East Anatolian
range (Late Miocene–Early Pliocene) fi ts poorly with
fault system (EAFS) located between Karlıova in the
the initiation age of the neotectonic regime in eastern
northeast and Samandağ-Karataş counties in the
Anatolia, as there were a series of coeval processes
southwest (Figure 1a). It meets the NW-trending
linked to the major slab-detachment event which pre-
dextral North Anatolian fault system (NAFS) around
dated the onset of a strike-slip neotectonic regime in
Karlıova and forms a conjugate system with it. Th e
eastern Anatolia, indicating a Late Pliocene initiation
EAFS is an intra-continental sinistral strike-slip
age of the neotectonic regime.
shear zone about 80 km wide and 700 km long. It
cuts across and sinistrally displaces the Bitlis Suture Th e third idea, suggested by Göğüş & Pysklywec
Zone formed by the fi nal continent-continent (2008), related to the nature of the neotectonic
collision of the Arabian plate to the south with the regime on the eastern Anatolian plateau, is that the
Eurasian plate to the north during the Late Middle eastern Anatolian plateau is the site of lithospheric
Miocene (Şengör & Yılmaz 1981; Dewey et al. 1986). thinning, plateau uplift , heating and synconvergent
However, the timing of transition from the fold- and extension resulting from delamination of the mantle
thrust-dominated to the reverse fault-dominated lithosphere, i.e. the huge central section of the east
palaeotectonic stage to the strike-slip faulting- Anatolian plateau is extensional while only its
dominated neotectonic stage, i.e. the initiation age northern and southern fringes are compressional.
of the neotectonic stage and formation of related Th ey also reported that the Kağızman, Tuzluca,
major structures such as the Anatolian platelet, the Hınıs, Karlıova and Muş basins are E–W-trending,
NAFS and the EAFS in east-southeastern Turkey, is normal fault-controlled extensional basins developed
still under debate. Several views on this problem have as a natural response to the synconvergent extension.
been expressed. Th e fi rst is that the Late Serravalian In contrast to the idea of these authors, there is a
continent-continent collision of the Arabian and big discrepancy between the site of extension they
Eurasian plates is the initiation age of the strike-slip suggested and the nature of both the structures and
neotectonic stage (Şengör 1980; Şengör et al. 1985; style of deformation patterns observed in eastern
Şaroğlu & Yılmaz 1987). Th e second idea, expressed Anatolian plateau (Koçyiğit et al. 2001). Th e central
by Faccenna et al. (2006), is that the ‘NAFS’ resulted part of the east Anatolian plateau is shaped by en
from slab-detachment beneath the Bitlis Suture Zone échelon folds, E–W-trending thrust-reverse faults,
in the Late Miocene–Early Pliocene. Th ey suggested N–S-trending extensional features such as normal
that slab detachment beneath the collisional belt faults and fi ssures, NE- and NW-trending strike-slip
triggered: (a) accretion of slab-retreat to the west faults and related pull-apart basins, i.e. the Kağızman,
owing to the increase in the slab pull-force, (b) the Tuzluca, Hınıs, Karlıova and Muş basins are strike-
indentation of the continent in the collisional area, slip fault-controlled pull-apart basins, not normal
and (c) the emergence of conditions that permitted fault-controlled grabens. Th ese locally extensional
the lateral westward escape of material and formation but regionally compressional features characterize
of the ‘NAFS’. Although the slab-detachment model strike-slip faulting and the related prominent
548
S. ÇOLAK ET AL.
n
ÇevrimpınarKZFZF39402GKPertBİNGÖLeKeban Damk 1 faKARAÖMER DAĞIult 3 PUSH-UP39ASKER DAĞIzoPalune eELAZIĞtnluoafz liksmaaBD natb4eKltuluaaffYolüstü fault zone çn4Figure 2ğeıGz08.03.2010alEMw: 6.1enozLake HazarFırtalut faafavouullUt 65SivriceF7ıreat nrivoerz tlu16.03.2010aefne Mw: 4.1nonzoa Karakaya Damtlzmu atfla ukyiaNmfı rdeeÇcA-iervciiLSmk 520Atatürk DamYarpuzlu bL E G E N DBlack Sea1−NAFS North Anatolian settlementBingöl pull-apart basinNAFS fault systemEurasian Plate2AnkaraKarakoçan pull-apart basinKarlıovastrike-slip faultFigure b EAFS: East Anatolian 3 Anatolian PlatetetKovancılar pull-apart basinfault systemBSZSstrike-slip fault4aF− APalu-Uluova pull-apart basinDSFS Dead Sea faulteESKarataş with reverse componentn asysteme5Lake Hazar negative flowergSamandağeA −structureKFZ Karakoçan faultstrike-slip faultus r6spuybCd zone-Hazar pull-apart basinunwith normal componentcatieong zoeArabian PlateenA htSuo7−KGFZ Karlıova-GöynükMalatya pull-apart basinMediterranean SeaScollision zoneF fault zoneNSDbasin infill200 km0100aAfrican Plate gure 1. (a) Simplifi ed map showing major plates and their boundary faults in Turkey and surrounding areas. (b) Simplifi ed map showing the Yarpuzlu-Bingöl sectioof the East Anatolian fault system, its major fault zones and the studied area (box-shaped insert on the map; Koçyiğit et al. 2003).
Fi
549
PALU-ULUOVA BASIN IN THE EAST ANATOLIAN FAULT SYSTEM
compressional neotectonic regime rather than a the master fault of the EAFS displays numerous
tensional tectonic regime in the eastern Anatolian srike-slip complexities such as extensional to
plateau. Th is was also indicated by the fault plane compressional step-overs, single and double bending
solution diagrams of large destructive earthquakes and bifurcations resulting in a series of push-ups
such as the 1966 Varto, 1971 Bingöl, 1976 Çaldıran, (e.g., Karaömerdağı, Askerdağı and Mastardağı
1983 Horasan-Narman and 2000 Karlıova (Bingöl) push-ups) and strike-slip basins of dissimilar nature,
earthquakes (Tan et al. 2008). geometry and size (e.g., the Bingöl pull-apart basin,
Th e fourth idea (Koçyiğit et al. 2001) was based on and the Palu, Uluova, Lake Hazar, Hazar and Malatya
the fi eld data. Th ey stated that 9.5 Ma elapsed between fault-wedge types of strike-slip basins) (Figures 1b &
the earlier palaeotectonic stage and the onset of the 2). Th e master fault of the EAFS begins to bifurcate
strike-slip faulting-dominated neotectonic stage in into several fault zones and single faults around Palu
the east Anatolian plateau. Th is transitional period County, namely the Pertek, Elazığ, Uluova, Yolüstü,
is an elapsed time interval during which occurred Sivrice and Adıyaman fault zones (Figure 1b). With
a series of regional inversions such as the inversion regard to the Palu-Uluova strike-slip basin, these
in tectonic regime, style and pattern of deformation, structures are described in more detail below. Apart
nature of magmatic activity, the type of basins and from these, other signifi cant structures include the
their stratigraphy, drainage system and also in the Baskil fault, the Lice-Çermik fault zones, the Genç
source of seismic activity. For this reason, the Late fault and the Fırat fault. Of these the fi rst-named
Pliocene initiation age of the strike-slip neotectonic two form the northwestern and the southeastern
regime post-dates both the slab-detachment and boundaries of the EAFS respectively (Figure 1b).
mantle lithosphere delamination (Hempton 1987; However, these latter four structures are outside the
Koçyiğit & Beyhan 1998; Koçyiğit et al. 2001).
scope of the present paper.
Various inversions are well-recorded and refl ected
by basin infi lls and their deformation patterns. For
this reason, detailed stratigraphy, sedimentology and Stratigraphic Outline
structural analyses of major and minor structures or
Palaeotectonic Units
fault arrays recorded in deformed and undeformed
Based on their age and deformation pattern, the rocks
basin infi lls have a key importance in determining
exposed in and around the Palu-Uluova basin can be
the transition from the palaeotectonic stage to the
neotectonic stage. A number of basins occur along classifi ed into two categories: (1) palaeotectonic rock
the EAFS, as along the NAFS (Hempton et al. 1983; units, and (2) neotectonic rock units. Palaeotectonic
Hempton & Dunne 1984; Westaway & Argar 1996; units are the intensely deformed (folded and thrust
Koçyiğit 1989; Aksoy et al. 2007). Th ey include, from to reverse-faulted) rocks of pre-Late Pliocene age.
NE to SW, the Bingöl, Karakoçan, Kovancılar, Palu- Palaeotectonic units consist of the Jurassic–Lower
Uluova, Lake Hazar, Hazar and Malatya strike-slip Cretaceous Guleman ophiolites, the Senonian Elazığ
basins (Figure 1b). Th ese basins have two basin infi lls magmatic rocks, Maastrichtian–Upper Palaeocene
separated from one another by an intervening angular Hazar Group, the Middle Eocene Maden Group, the
unconformity, i.e. they are superimposed basins Middle–Upper Eocene Kırkgeçit Formation and the
(Koçyiğit 1996). Th is stratigraphical relationship and Upper Miocene–Lower Pliocene Çaybağı Formation
the records of other inversions together reveal that (Sungurlu et al. 1985; Hempton 1985; Herece & Akay
the strike-slip neotectonic regime emerged in east- 1992; Aksoy 1993; Çelik 2003; Koç Taşgın 2009).
southeast Turkey from the Late Pliocene onwards. All but the latter rock-stratigraphic unit (Çaybağı
Th e present paper aims to introduce new fi eld data Formation) which is the youngest palaeotectonic unit,
obtained from the Palu-Uluova strike-slip basin in are outside the scope of the present paper. However,
the EAFS. Th ese data fi t well with the Late Pliocene
in order to distinguish between the palaeotectonic
onset age of the neotectonic regime in this basin.
units and the neotectonic units, the stratigraphy and
Th e Bingöl-Yarpuzlu section of the EAFS is deformation pattern of the Çaybağı Formation will
structurally very complicated. In this section, be described in more detail.
550
S. ÇOLAK ET AL.
Çaybağı Formation it may have been faulted and considerably down-
thrown.
Th e Çaybağı Formation, fi rst named by Türkmen
(1988), was later studied in more stratigraphical For easy understanding of the various lithofacies
and sedimentological detail by Koç Taşgın (2009). of the Çaybağı Formation and their depositional
It comprises a thick (measured maximum thickness settings, the measured stratigraphical section
is 1987 m) fl uvio-lacustrine sedimentary sequence (Figure 3) of the Çaybağı Formation and other
made up of numerous lithofacies (Figure 3). Both the measured sections carried out outside the study
top and bottom contact relationships, particularly its area were compiled, modifi ed and simplifi ed into
lower half and bottom contact relationship with older four members. Th ese are, from bottom to top, the
rocks, are poorly exposed owing to superimposed Hacısamdere, the Yılankaya, the Ziyarettepe and
palaeotectonic and neotectonic structures such as the Arılar members (Figure 4). Th e Hacısamdere
overturned folds, reverse and strike-slip faults within member is the lowest facies of the Çaybağı
the zone of active deformation (East Anatolian Formation. It overlies with angular unconformity
fault system) in the study area. Th erefore, only the Upper Eocene–Lower Oligocene clastics and
faulted, dissected and exposed parts of the Çaybağı Nummulite-bearing limestones exposed northeast
Formation could be measured in the study area (a in of Palu, but outside the study area (Sungurlu et al.
Figure 2; Figure 3). For this reason, the thickness of
1985). Th e Hacısamdere member is a fi ning-upward
the Çaybağı Formation varies from ~2 km to 0.8 km
sequence deposited by a fl uvial system. It consists
in places. However, its normal stratigraphical basal
of polygenetic basal conglomerate and sandstone at
contact relationships with older rocks are well exposed
the bottom but an alternation of siltstone, mudstone,
in other areas including Perisuyu River, Darıkent,
channel conglomerate and claystone towards the top
Akpazar and Ekinözü settlements located outside
(Figure 5). Th e measured thickness of this member is
the study area from 11 to 34 km north-northwest
about 350 m (1 in Figure 4). Th e Yılankaya member
of Palu County (Koçyiğit 2003). At these localities,
consists of a thick-bedded conglomerate, sandstone
the Çaybağı Formation overlies with angular
and red mudstone alternation. It displays well-
unconformity a shallow marine to fl uvial sedimentary
developed graded bedding, planar cross-bedding
sequence comprising a sandstone-marl and
and pebble imbrication sequence about 200 m thick
Nummulite-bearing limestone alternation (Kırkgeçit
which indicates a braided fl uvial depositional system.
Formation) of Middle–Late Eocene age (Türkmen
Both the Hacısamdere and the Yılanlı members
1991), and it displays both a lateral and vertical
characterize marginal facies comprising the lower
transitional contact relationships with the Middle
part of the Çaybağı Formation. Th ese two members
Miocene–Lower Pliocene volcano-sedimentary
are not exposed within the Palu-Uluova basin owing
Karabakır Formation (Çetindağ 1985; Sungurlu et al.
to faulting and deep burial. However, they display
1985; Koçyiğit 2003). In the same region, both the
both lateral and vertical gradations with the Ziyaret
Karabakır and the Çaybağı formations are underlain
Tepe member outside the study area (Figure 4).
comformably by a fl ysch sedimentary sequence
(‘Kuşaklı Flysch’) with abundant intercalations Th e Ziyarettepe member is the most widespread
and olistholiths of Aquitanian–Burdigalian reef unit in the study area (Figure 2). Its measured
structures (Koçyiğit 2003). Volcanic rocks (dacite, thickness is about 1175 m (3 in Figure 4). It is
andesite, rhyolite, basalt and their pyroclastites) of represented by a thick fl uvio-lacustrine sedimentary
the Karabakır Formation were previously reported sequence composed of an alternation of cross-bedded
to be the west-southwestern continuation of the conglomerate, cross-bedded to parallel laminated
Upper Miocene–Lower Pliocene Solhan Volcanics sandstone, red mudstone, clayey lacustrine limestone
(Seymen & Aydın 1972; Yılmaz et al. 1987; Ercan et and marl with coal and tuffi te intercalations. In
al. 1990). Consequently, the Çaybağı Formation is addition the Ziyaret Tepe member is full of soft -
not exposed within the Uluova basin due to a thick sedimentary features such as slump folds, broken
cover (Quaternary neotectonic infi ll) and water formation, normal and reverse growth faults, load
accumulation behind the Keban Dam. In addition, casts, fl ame structures, sand dykes and convolute
551
PALU-ULUOVA BASIN IN THE EAST ANATOLIAN FAULT SYSTEM
alu nt ntult ult
SH-UP Pb NFMISAB U L Baltaşı strike-slip faultstrike-slip faultwith normal componestrike-slip faultwith reverse componeoblique-slip normal fa oblique-slip reverse fa master fault (Y-shear)MF settlementslocation of measuredasections in Figure 7
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alluvial fan Quaternary −upper PliocenePleistocenePalu Formation upper Pliocenetravertine deposits−upper MioceneLower PlioceÇaybağı Formation3915pre-Upper Miocenebasement rocks ULU Ballı ca Kavaktepe e 2. Simplifi ed map showin
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Fi
552
S. ÇOLAK ET AL.
ON an
400 PALU FORMATI alluvial f EXPLANATIONS
horizontal lamination
800
Gastropoda
Lamellibranch
Lamellibranch fragments
Ostracoda
macrophyte fragments
300
macrophyte
alluvial fan(distal fan) rphailzaoeloitchusrrent direction
700
e gravel orientation
n
ustri imbrication
c
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ÇAYBAĞI FO200 delta front - shallo ĞI FORMATION mpsalaanntdraisxrt -ocsnruoepsps-osrttreadti ficeodn gcolonmgleormateerate
A600 lenticular shaped sandstone
B
Y
A
Ç planar cross-stratified sandstone
trough cross-stratified sandstone
ripple cross-laminated sandstone
red mudstone
100 e siltstone
n
ustri grey claystone
c
a
n l carbonaceous claystone
e
p
500 o
nt - clayey limestone
o
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elt
d limestone
coal
er
et
m
0
Keban
DLaakme claysiltsfamncd g2r 1a0vel claysiltsfamncd 2g 15r a 3 0v el
Figure 3. Measured stratigraphic column of the Çaybağı and Palu formations (2 km N of Yolüstü village). For location of the
section, see Figure 2 (modifi ed and simplifi ed from Koç Taşgın 2009).
553
PALU-ULUOVA BASIN IN THE EAST ANATOLIAN FAULT SYSTEM
Thick.
Age Unit Lithology Description
(m)
r
e
b
m
Me 12 4− alluvial fan facies association represented by
r 8 massive conglomerate, red mudstone and grey-red
a
ıl mudstone alternation
Ar 4
−
4 4
e
n
e 3− delta top, delta front, shallow lacustrine and
c open lacustrine facies association represented by
o
li on 7 clayey limestone, marl, conglomerate, sandstone,
P ti 8 mudstone with organic material, claystone and
y a 9 peat
l m 1
ar or al: 5
−e E ğıa F ber tot 117
n b m 3
e y e
a M
c
o Ç e 0
i p 0
M Te 2 2− low-sinuosity river facies association
ate yaret r 2 .......... raenpdr eresedn mteudd bstyo cnoenglomerate, sandstone
L Zi be 0 3
− m 5
r 3 e 3
e M
mb e 1
r
Me De ...........
kaya ısam 2 ............. c1o−n bgrlaoidmeedr artivee arn fadc sieasn dassstooncieation represented by
n c
a a
−ı2 Yl −1 H ................... 1
angular unconformity
e
n
pre-oce older rocks: mostly ophiolitic, magmatic and
Mi sedimantary rocks
Figure 4. Generalized stratigraphic column of the Çaybağı formation.
554
S. ÇOLAK ET AL.
b
a
Figure 5. General view of the red mudstone (a) and conglomerate (b) alternation comprising the Hacısamdere member of the
Çaybağı formation (2 km NE of Yolüstü village, view to NW). For location of the photograph, see Figure 2.
bedding which indicate the fault-controlled Consequently, the entire Çaybağı Formation
sedimentation of the Çaybağı Formation (Hempton is characterized by a thick fl uvio-lacustrine
& Dewey 1983; Koç Taşgın & Türkmen 2009). Both sedimentary sequence about 2 km thick. It is assigned
the lithofacies and syn-sedimentary structures in the a Late Miocene–Early Pliocene age, based on its rich
Ziyaret Tepe member reveal that it was deposited fossil content, including Candona neglecta Sars,
in delta front and shallow to open lake depositional Candona (Candona) paralella pannonica Zalanyi,
settings (Figure 3). Heterocypris salina (Bradyi), Cyprideis sublitoralis
Th e fourth and fi nal member is the Arılar member, (Pokorny), Cyprideis anatolica Bassiouni, Cyprideis
measured to be about 812 m thick (4 in Figure 4), (Cyprideis) anatolica Bassiouni, Cyprideis pannonica
which comprises the uppermost part of the Çaybağı (Mehes), Cyprideis torosa (Jones), Valvata debilis
Formation. It is a coarsening-upward sequence Fuchs, Valvata piscinalis (Müler), Hydrobia ventrosa
and consists of a matrix-supported, polygenetic Montfort, Margaritafera (Pseudounio) fl abellata
boulder-block conglomerate and red-grey mudstone trajani Michailovsky, Potomida (Potomida) sibinensis
alternation. Pebbles in the conglomerates reach up (Penecke), Unio (Crassunio) batavus (Nillsson), Unio
to 65 cm in diameter and have been derived from aff . hilberi Penecke, identifi ed at its diff erent levels
the northerly located Senonian magmatic rocks and (Koç Taşgın 2009). Th is age is also supported by some
the Middle–Upper Eocene Kırkgeçit Formation. other fi eld observations. As mentioned previously,
Th e various lithofacies types comprising the Arılar the Çaybağı Formation rests conformably on the
member reveal that it was deposited by braided to Aquitanian–Burdigalian ‘Kuşaklı Flysch’ and displays
meandering high energy fl uvial systems including both vertical and lateral gradations into the volcano-
alluvial fans and fl ood plain. sedimentary sequence of the Upper Miocene–Lower
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PALU-ULUOVA BASIN IN THE EAST ANATOLIAN FAULT SYSTEM
Pliocene Karabakır Formation in the north and into folds and reverse faults along the pressure ridges
outside the study area (Sungurlu et al. 1985; Koçyiğit bounded by the strike-slip faults with reverse-slip
2003). Th e radiometric age of the youngest volcanic component. One such well-developed pressure ridge
rocks comprising the uppermost horizon of the is exposed on Orta Hill located approximately 2 km
Karabakır Formation is 4.1±0.32 Ma (Sanver 1968), south-southwest of Örencik village. Th is locality
showing that the Karabakır Formation extends into could not be indicated on the Figure 2 owing to the
the Lower Pliocene. small scale of the map.
Based on their structure, texture, origin,
stratigraphical position, and tectonic setting, the
Neotectonic Units (Strike-slip Basin Infi ll)
Baltaşı travertines can be correlated with both
Except for the units deformed in the pressure ridges,
the Kızılca Travertine exposed in Kızılca village
these are, in general, nearly horizontal, undeformed
(Karakoçan-Elazığ) (Koçyiğit 2003) and the
and weakly lithifi ed to unconsolidated sedimentary
Hüdaihamamı Travertine (Sandıklı-Kütahya) (Saraç
deposits of Plio–Quaternary age. Neotectonic units
2003). Th e Kızılca travertine is also laminated to
are of two major categories: (1) travertine, and
thick bedded, iron-rich, nearly horizontal and 80
(2) fl uvio-lacustrine sedimentary sequence (Palu
m thick. It overlies with angular unconformity
Formation). Th ey mostly occur in the strike-slip
the Upper Miocene–Lower Pliocene Karabakır
basin (Figure 6).
Formation volcanics at its base, while it is overlain
Travertines – Based on the age, degree of conformably by Early Quaternary coarse-grained
lithifi cation and the depositional setting, travertines terrace conglomerate. Th e Hüdaihamamı travertines
exposed in the study area are either older and highly are likewise thick-bedded to massive, overlie
lithifi ed travertines (Baltaşı travertines) or actively with an angular unconformity the Palaeozoic
forming recent travertines. Older travertines are well metamorphics beneath, and display both vertical
exposed as uplift ed and fault-suspended outcrops and lateral transitions into Plio–Quaternary fl uvial
ranging in area from a few 10 m2 to a few km2 along conglomerates. A mammalian fossil, Mimomys
the fault segments comprising the northeastern parts Plioacenicus, which indicates a Upper Pliocene
of the Adıyaman fault zone around Baltaşı village horizon (MN 16), was identified within these fl uvial
(Figure 2). Th ese are laminated, thick-bedded to clastics (Saraç 2003). Consequently, a relative Late
massive, highly porous and iron-rich carbonate Pliocene–early Quaternary age can also be assigned
accumulations precipitated from the CaCO -rich to the Baltaşı travertine comparable with both the
3
ground water springs along fault segments and open
Kızılca and Hüdaihamamı travertines.
cracks (fi ssure ridges) formed during the initial stage
Th e second category of travertines is actively
of strike-slip faulting. Th ey overlie with angular
growing carbonate precipitations exposed along the
unconformity the underlying Jurassic–Lower
master fault of the Sivrice fault zone cutting across the
Cretaceous ophiolitic rocks (Guleman ophiolite),
basin fl oor. Th ese travertines occur in diverse-sized
but have a free erosion surface at the top. Th e Baltaşı
(a few m2 to 300 m2) and fault-parallel aligned patch-
travertines begin with basal thin and non-mappable
like outcrops located approximately 7 km west of the
basal clastics, which are overlain by an alternation
Kumyazı village (c in Figure 2). Th ese are the fissure-
of thin- and thick-bedded to massive travertine
ridge type of travertine made up of partly lithified,
horizons up to about 35 m thick around Baltaşı
laminated to massive and highly porous Quaternary
village. Development of the Baltaşı travertines has
carbonate precipitations. Th ese conformably overlie
now ceased. Th e Baltaşı travertines are one of the
the fan-apron deposits beneath, and they have a
lithofacies formed during the early development
free depositional to erosional surface at the top. Th e
stage of the strike-slip basin. Later, the Baltaşı
measured thicknes of the actively growing travertines
travertines were uplift ed, dissected and exposed as
is about 8 m (c in Figure 2 & Figure 7c).
fault-suspended terraces at higher elevations above
the present basin fl oor, while their lateral clastic Palu Formation – First recognized and named by
counterparts are being locally deformed and thrown Çetindağ (1985) in Palu County, it consists mainly
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