Recent volcanism, tectonics and plate kinematics near the junction of the African, Arabian and ...

15 Pages·1998·1.15 MB·English

JournalofVolcanologyandGeothermalResearch85(cid:14)1998.1–15
Recent volcanism, tectonics and plate kinematics near the
junction of the African, Arabian and Anatolian plates in the
eastern Mediterranean
M. Tekin Yu¨ru¨r a,), Jean Chorowicz b
a HacettepeUni˝ersity,DepartmentofEngineeringGeology,06532,Beytepe,Ankara,Turkey
bUni˝ersite´Paris6,Ge´otectonique,Case129,LGGST,4placeJussieu,75252Paris,France
Abstract
IntheEasternMediterranean,plateconvergenceoccursbetweenAfrica–ArabiaandAnatolia.TheAfricarArabiamotion
is a strike-slip displacement along the Dead Sea fault. The AfricarAromvFpefoaangarlutaiiachnlotmatoeln.nysleaiIietslanewmftrmahaesdusrpoaetdlrwttneoiitdosadipuonrusldrnacpfi,teaaseadccrsneete.datcshkTgoroaeenhelsnosevestdieoriuoeautcpelslcidsyatfebittooedrhyldnaeldtoseaowpwuffrbsoieetudrrdhsmigueggbcnsaiedtytctirsi-eoiotpaknnollfeaksof-starseotallwiurtikhpetobihenarameeEsnolamaadfalCjsttaoeteytardixAplctotrsteneonucnabgsttsa.oeoittnolThwNiinaeche–neetpASenfhccamacotuAosoanlenrtnmvasioaecbpstrsirhsga.eflae,isatNpnsuAaicelroftefaa,fnrrtei.ebtcchteaTthoeethwefadnen7eotsde.rmor8intpuAh–olterA9ehnereanrmjaatruosebemntlcnieicaeradrtnniyaoutsenTnsemadigunrsmo.rgAikvnTeeerncnhyemaetectneeoo2mennlfiattaaMstrxhpatiiaelhsmar,eetDuteaajdmeukmaifneridfesonciscttnSuiituiooeertpdnnaee along the East Anatolian fault. The analysis of the
displacementrecognisedforthisstructurebeingaround15km,wehaveobtained1.9Maasthemaximumageforthefault
formation. The volcanic, tectonic and kinematic data converge to propose a ca. 2 Ma age for the change of local tectonic
regime in the junction area. The structural mapping, the geometry of the fractures used by the magma to reach the surface
and the presence of alkali basalt of mantle source suggest that the deformation along the northern end of the Dead Sea
transform,i.e., theAmanosfault,wasmodifiedbytheformationoftheEastAnatolianfaultzone.Inthisregion,apparition
oftheEastAnatolianfaultaccommodatingwestwardmotionoftheAnatolianplateresultedinoblique-sliptensionalongthe
Amanos segment of the Dead Sea transform, giving rise to a fissure-fed, mantle-derived alkaline volcanism at ca. 2 Ma,
whichlasteduntilrecenttimes(cid:14)0.4 Ma.. q1998ElsevierScienceB.V. All rightsreserved.
Keywords:neotectonics;faultmovements;alkalinevolcanism;platekinematics;SETurkey;EastAnatolianfault
1. Introduction AfricaandArabia(cid:14)McKenzie,1970,1972;Deweyet
al., 1973; Sengo¨r et al., 1985.. During the middle
The present-day geodynamics of the Eastern
Miocene, Arabia was separated from Africa along
Mediterranean results from the relative motion be-
the left-lateral Dead Sea fault zone (cid:14)e.g., Le Pichon
tween three continental plates, namely: Eurasia,
and Gaulier, 1988.. In the middle to late Miocene
time interval, the northern border of Arabia entered
)Correspondingauthor.Tel.: q90-312-235-25-42;Fax:q90-312-299in-2t1o-36c;oEll-imsiaoiln:[email protected] margin of Eurasia
(cid:14) e.g.,Perinc¸ek,1979. ,formingtheBitlisThrustZone.
0377-0273r98r$19.00q1998ElsevierScienceB.V.Allrightsreserved.
PII: S0377-0273(cid:14)98.00046-8
2 M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15
Contemporaneously with this collisional event (cid:14)ca. Jackson and McKenzie, 1988., part of the hitherto
13 Ma, e.g., Le Pichon and Gaulier, 1988. or later shortened and thickened Eurasian lithosphere began
(cid:14)Pliocene, ;5Ma,BarkaandKadinsky-Cade,1988; to move west, towards the Hellenic subduction zone
M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15 3
where the northern African oceanic slab is under- (cid:14)1995., with the authors, by means of satellite im-
plated (cid:14)e.g., McKenzie, 1972; Le Pichon and Ange- agery and microtectonic analysis. They presented
lier, 1979.. The lateral extrusion of this lithospheric some characteristics of the regional stress pattern on
mass, the Anatolian block, is accommodated by two the basis of stress tensors computed using fault
transform faults, the North Anatolian fault (cid:14)Mc- striation data.
Kenzie, 1972;Sengo¨r,1979;JacksonandMcKenzie, In this paper, we make use of the structural data
1984. and the East Anatolian fault (cid:14)Arpat and obtained in the field (cid:14)Yu¨ru¨r, 1992.. The data consist
Saroglu, 1972, 1975; Seymen and Aydin, 1972; of displacement vectors observed as slickensides on
McKenzie, 1976.. Recent space geodetic data analy- fault planes. Existing geological maps and our satel-
sis (cid:14)Oral et al., 1994; Le Pichon et al., 1995. has lite image and field analyses are used to produce a
confirmed the westerly motion of the Anatolian fracture map near the Maras junction. We then pre-
block. sent data concerning the recent volcanism studied in
For several workers (cid:14)McKenzie, 1972; Sengo¨r et detail by C¸apan et al. (cid:14)1987.. This section will help
al., 1985; Gu¨len et al., 1987., the junction between to confirm the lithospheric nature of the Amanos
Anatolia, Arabia and Africa is located near Maras, fault and precise the chronology of the change of
SE Turkey (cid:14)Fig. 1.. There are different models be- tectonic regime. Analysis of the kinematics based on
cause the regional deformation is of polyphased current plate motions and space geodesy data will
character, attested by the presence of late Neogene help to establish the present-day plate motions with
angular unconformities (cid:14)Kelling et al., 1987; Yilmaz which we have computed the initiation age of the
etal., 1988;KarigandKozlu,1990., andthefractur- East Anatolian fault. These multi-source data taken
ingpatternnearMarasisrelativelycomplex(cid:14)Fig. 1.. together suggest that the study area has experienced
According to McKenzie (cid:14)1976., the East Anatolian achangeoftectonicregimeduringwhichaconsider-
fault zone continues west of the junction and is ably rapidfissurevolcanismwas generatedalongthe
linked with the Cyprean Arc, along which the Amanos fault. This paper shows how multi-source
AfricarAnatolia convergence is taken up by means data can help in understanding and dating the rela-
of thrusting and strike-slip faulting (cid:14)Fig. 1a.. Field tionshipsbetweenalocaltectonicchangelinkedwith
work and seismic profile analyses of Perinc¸ek and more general plate tectonics, and the occurrence of
C¸emen (cid:14)1990. suggest that the East Anatolian and volcanism.
the Dead Sea fault segments in Turkey may be
considered as one broad fault system. Along the
2. Structural data
Amanos fault (cid:14)Fig. 1., recent basaltic rocks, dated at
2–0.4 Ma (cid:14)C¸apan et al., 1987., are vertically offset We essentially have measured slickensides and
forseveralhundredmeters(cid:14)ArpatandSaroglu,1972.. extensionveinsalongeitherthemajorfaultplanesor
Some geologists expressed the thesis that the north- along nearby faults with planes subparallel to that of
ernmost segment of the Dead Sea fault is located the major fault, assuming that subparallel planes
east of the Amanos fault, and terminates against the close to each other are affected by the same tectonic
Taurus Range near Go¨lbasi (cid:14)C¸apan et al., 1987; regime and bear geometrically and mechanically
Perinc¸ek and C¸emen, 1990.. The area was also stud- similar tectoglyphes. Some fault planes display evi-
ied by Lyberis et al. (cid:14)1992. and Chorowicz et al. dences of successive deformations. A good field
Fig.1.Structureofthestudiedarea.(cid:14)A.MajorneotectonicstructuresandplateconfigurationinandaroundAnatolia.BTZ:BitlisThrust
Zone; DSF: Dead Sea fault; EAF: East Anatolian fault; NAF: North Anatolian fault; T: Tu¨rkoglu. Arrows are drawn parallel to plate
motionsrelativetoEurasia.(cid:14)B.SimplifiedgeologicalmapoftheareasurroundingtheMarasJunction,drawnfroma1r250000scale,false
colours, LandsatTMImage, path174, row34, acquiredon October22, 1989. We madeuse of the geologicalmapsof Dubertret(cid:14)1955,
1962.andPonicarov(cid:14)1967.fortheSyriansector,the1r500000scaleAdanaandHataysheetsofMTA(cid:14)1962a,b.,Yalc¸in(cid:14)1979.,Arpatand
Saroglu(cid:14)1975.,Muehlberger(cid:14)1981.,MuehlbergerandGordon(cid:14)1987.,Perinc¸eketal.(cid:14)1987.andYilmazetal.(cid:14)1988..Wealsobenefited
from field observations and satellite image interpretations. AB: Amik basin; An: Antakya; EAF: East Anatolian fault; G: Go¨lbasi; Ga:
Gaziantep;M:Maras.
4 M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15
Fig.2.Mapofthe‘older’motionsobservedalongthemajorfaultplanes.
M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15 5
Fig.3.Mapofthe‘recent’motionsobservedalongthemajorfaultplanes.
6 M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15
Table1
Faultlinesandslip-vectordirectionsofthesuccessivemotions
M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15 7
evidence to establish the relative fault-motion South of the Bitlis Thrust Zone, the western part
chronology along the same fault plane comes from of the Amanos Range has suffered left-lateral trans-
the overprinting of different striations. If we observe pression (cid:14)sites 50, 43, 47., strike-slipping (cid:14)sites 17,
on a fault plane the lineation L to overprint the 18, 49. or compression (cid:14)sites 44, 48.. More to the
2
lineationL , weconsiderL torepresentarelatively south, NNE-striking transcurrent faulting appears to
1 2
recent fault motion with respect to the motion that affect the southwestern sector of the Amanos Range
created L . Another criterion to accept that a fault (cid:14)sites 14, 33, 34, 35, 36.. However, in some sites of
1
plane has experienced relatively recent displace- the latter zone, SW-trending displacements are ob-
ments is the presence of unconsolidatedfault breccia served as ‘older motions,’ along one strike-slip fault
along the fault plane. (cid:14)site37.andtwotranstensionalfaults(cid:14)sites7,15..In
Our data collected in the field are represented on the southern part of the study area, various fault
maps in the form of fault direction lines, and arrows displacementshavebeenobserved.Amongthem,the
corresponding to the azimuth of the plunge of the approximately N-striking transcurrent faults of the
striations (cid:14)Figs. 2 and 3.. The fault direction is the sites8 and10 canbe interpretedas formedin a N–S
mean azimuth of the main fault system observed in crustalconvergencezone,butalsotranstensionalmo-
the station. In this study, directions are all clockwise tions recorded at sites 2, 5 and 12. The NW–SE-
angular values from the north (cid:14)Table 1.. The arrows orientedcompressioninsite6affectsonlytheEocene
converging to the fault direction line represent com- and the Langhian rocks. SW-oriented transport as
pressive structures, while diverging arrows corre- suggested by strike-slip faulting in sites 1 and 16 is
spond to extension structures. also observed in sites 51 E (cid:14)in Eocene thrusts and
We have prepared two maps, one for the rela- overturned folds. and 51 M (cid:14)in Miocene thrusts..
tively ‘older’ motions (cid:14)Fig. 2. and another for the Finally, microtectonic data for the ‘older motions’
‘recent’ motions (cid:14)Fig. 3.. In Table 1, we have pre- support in majority a N–S compression, with local
sented the structural data with the ages of the variations.
youngest rocks affected in the measurement station.
3.2. More recent motions
3. Slip motions around the junction
In some sites (cid:14)e.g., site 28, 31, and 43 of Fig. 3.
3.1. Older motions along the Bitlis Thrust Zone, a change of tectonic
regime is evidenced (cid:14)1. by the presence of older
The ‘older’ fault motions are presented in Fig. 2. lineations overprinted by more recent ones (cid:14)fault
The geometry of the folds and fault lineations sug- plane reactivation. testifying to extensional faulting
gests a tectonic transport oriented north–south, as or (cid:14)2. by normal faults cutting and offsetting the
already noticed by previous workers. Folding and thrust planes.
thrusting along the Bitlis Thrust zone (cid:14)sites 20, 21, Geological mapping (cid:14)Dubertret, 1955; Ponicarov,
25, 29, 30, 31, 51 E and 51 M. have accommodated 1967. and satellite image analyses (cid:14)Muehlberger,
the N–S convergence between Eurasian hinterland 1981; Muehlberger and Gordon, 1987. suggest the
and the Afro-Arabian foreland. presence of recent faulting east of the Amanos fault,
NotetoTable1:
Theyoungestrockaffectedbyeacheventisgiveninthelastcolumn.‘EocenelmiddleMiocene’denotesthefaultedcontactbetweenthe
Eocene and Middle Miocene rocks. Azimuths of fault planes in the second row from left are all clockwise values from the north.
Slip-vectorsaredrawnintheNWortheSWquadrants.Inthe‘Explanation’column,thetypeofthefieldevidenceusedtoestablishthe
relativechronologybetweenthefaultmovementsisgiven,ifthischronologyisdetermined.LINw2x:lineationoverprinting,thefollowing
numberinbracketsindicatesthenumberofobservations;TrF:extensionveincutandoffsetbyafault;F:faultcuttingthewholerockmass;
OEV:openextensionveins;OCV:coexistenceofopenandclosedextensionveins,c:closed,o:openveins;P-QF:Plio-Quaternaryfaulting;
QF:Quaternaryfaulting;AF:activefaulting.
8 M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15
with strands parallel to the Amanos structure, and site conjugate right-lateral faults trending N 1288–
disrupting Plio-Quaternary volcanic rocks. The east- 1508.
ernmostof themisnamedheretheAafrinefault. We Satellite imagery and microtectonic data indicate
have studied a segment of this fault in the Miocene thatfracturesinthiszonehavedirectionssubparallel-
rocks of site 22 (cid:14)Fig. 3.. The N 208–358-strikingand ing either the East Anatolian fault (cid:14)ca. N 658. or the
steeply dipping fault plane displays subhorizontal Amanos fault (cid:14)ca. N 308.. In sites 21 and 23, the
slickensides,suggestingstrike-slipdisplacementwith orientation of open extension veins suggest, respec-
left-lateral separation. We have also observed in the tively, NNW–SSE- and E–W-trending extension.
Fig.4.(cid:14)a.GeologicalmapshowingtheNarlivolcanism.ThemapbenefitedfromtheinterpretationofamultispectralSPOTimage(cid:14)scale:
1r100000, false colours, Ks119, Js275, acquired on July 14, 1987.. (cid:14)b. Inset picturing the structural interpretation of the Narli
volcanism.TheconcentriccirclesinbetweenthefaultsrepresenttheNarlivolcano.Strike-slipfaultingandopeningwereassociatedwith
E–W-orientedminimumhorizontalstress s andN–S-orientedmaximumhorizontalstress s.
3 1
M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15 9
This is mechanically compatible with striations In this interpretation, the older N–S compression
trending E–W and ENE–WSW. In site 32, we have hasclosedall thefracturesandpreventedthemagma
studied a fault plane separating Quaternary slope from going up to the surface. The more recent
scree from the late Miocene rocks. The fault trends extensional and strike-slip faulting has opened the
N 1158 to N 1208. Arpat and Saroglu (cid:14)1975. and faults and joints to give way up to the magma. This
Yalc¸in(cid:14)1979.havemappedthisstructureasasubac- interpretation is coherent with the following
tive normal fault. The fault plane bears E–W lin- volcano-tectonic data.
eations attesting for transtension.
East of the junction of the East Anatolian and
Amanos faults at Tu¨rkoglu (cid:14)Fig. 1., and in the 4.2. Narli ˝olcanism related to tectonics at local
scale
northern part of the Karasu Basin, we have observed
onsatelliteimagesstraightsegmentsandmanyirreg-
ularities, such as braiding channels, enlarging or As pointedout by C¸apan et al. (cid:14)1987., the Karasu
narrowing river channels (cid:14)Aksu river., suggestive of valley was a site of volcanic emplacement. In the
a recent fault zone. One of them, the Narli fault, has northern part of this valley, we have observed in a
been recognised in the field as a recent structure 20-m ground resolution multispectral SPOT image
(cid:14)Yalc¸in, 1979.. At the western termination of this and in the field a small basaltic cone (cid:14)Narli volcan-
fault, a recent volcanism has developed as suggested ism, C in Fig. 4a.. The cone is located on the
by fresh outcrops of basaltic flows (cid:14)Fig. 4.. This flat-lying Eocene marine limestone of the Arabian
structure will be studied in Section 4. platform. When the lava cover is thin, near the cone,
In this zone, we have observed, in a chrome mine it is eroded and in places, the underlying white
gallery opened in the serpentinized ophiolites (cid:14)site Eocene limestone is easily recognised from the bed-
45, Fig. 3., a fault plane which is known by the ding traces, giving an overall light-grey tone. To the
miners to have been active during a recent earth- east, darker and, consequently, probably thicker vol-
quake (cid:14)pers. comm. in 1990 with Akgu¨n Ilcan and canic rocks are distinguished in the satellite image.
Riza Soypak, responsible engineers of the exploiting No other volcanic cone can be observed to suggest
company, Gu¨neydogu Krom Isletmeleri, Istanbul.. that the darker volcanic rocks have come out from a
The direction of this active fault is N 528, dipping different centre. The difference in thickness may be
NW 848. The pitch of striations is W 268. The related to erosion across a fault. The boundaries
left-lateral slip-motion is clearly marked by fault between the darker and lighter basaltic groups form
striations on the hanging-wall fault plane. This slip- an alignment of rectilinear figures (cid:14)from ‘A’ to ‘B’
vector of this transtensional fault is oriented N 2358. in Fig. 4.. Weinterpretthealignmentas a N-striking
fault where the downthrown eastern compartment is
relatively less eroded, exposing thicker basalt. A
recentleft-lateralstrike-slipfault,describedbyYalc¸in
4. Volcanism
(cid:14)1979., is observed in the image west of the Narli
cone. Morphologic linears observed in the fluviatile
4.1. Relationships with the tectonics deposits of the Aksu river (cid:14)‘C’ in Fig. 4. also attest
for the recent activity of the Narli fault. In the field,
The comparison of the ‘older’ and the ‘recent’ we have observed near the crater of the cone N
motions indicates that the triple junction zone has 1608-striking extensional fractures attesting for N
first suffered from a N–S compression. This was 708-trending extension, compatible with left-lateral
followed by westward crustal displacements induc- displacementalong the N 608 Narli fault. Left-lateral
ing extensional and strike-slip faulting. We interpret displacementsalongtheN–Sfaultsarealsocompati-
that this tectonic regime change near the Maras ble with the N 1608 extensional fractures unless we
junction, has developed under the influence of the admit that the compressive strain component is hori-
extrusion movement of the Anatolian block with the zontalandtrendsN1608(cid:14)strike-slipregimeofdefor-
formation of the East Anatolian fault. mation..
10 M.T.Yu¨ru¨r,J.ChorowiczrJournalofVolcanologyandGeothermalResearch85(1998)1–15
Inthisgeometry,theNarlivolcanoisrootedonN We point out some conclusions of C¸apan et al.
1608extensionalfractures,attheextensionaljunction (cid:14)1987.:(cid:14)1.Complicatedblockmovementshavetaken
of the Narli fault with the N-striking faults, both place along the Karasu valley, leading to NE-trend-
left-lateral. The extensional junction may have pro- ing tensional fractures which might represent chan-
vided the distension necessary to generate and con- nelsforoutpouringofthebasalt.(cid:14)2.TheQztholeiite
duct the volcanic rocks to the surface (cid:14)Fig. 4b.. series have been contaminated by crustal material,
while the younger alkali olivine basalt series is the
4.3. Karasu ˝olcanism
productofamoredepletedsource,butbothfallonto
The petrography, geochemistry and radiometric the mantle array. (cid:14)3. The alkali basalt was trans-
agedeterminationofthevolcanicrocks(cid:14)Karasuunit. ferred more rapidly to the surface and this may be
along the Amanos fault were carried out by C¸apan due to a transitory behaviour of the fault in an
and coworkers in 1987. K–Ar age determinations extension regime. These conclusions are coherent
indicateagesrangingfrom2–0.4Ma(cid:14)latestPliocene with our observation of a later extensional event
and Quaternary.. The volcanic units were previously related with the occurrence of the uppermost
mapped by Dubertret (cid:14)1955, 1962. and recognised Pliocene–Quaternary volcanism.
on the basis of morphological and photogeological
studies to be related to the recent tectonic activity 4.4. How the Amanos fault kinematics ha˝e changed
(cid:14)Arpatand Saroglu, 1972.. Accordingto the authors,
the southern part of the Karasu valley, a narrow The ‘older motions’ characterised by a N–S-
structural basin extending east of the Amanos fault, trendingcompressioncanberelatedtoplatecollision
is covered by fissure eruptions and sheet flows of occurring since the middle Miocene between the
fresh lava of both ‘aa’ and ‘pahoehoe’ type. The northern margin of AfricarArabia with the southern
emission centres are located along NE-trending fis- margin of Eurasia (cid:14)e.g., Yilmaz et al., 1988;
sures.Theirworkshowsthatthevolcanismisformed Chorowicz et al., 1994.. This convergent phase was
by a succession (cid:14)from older to younger. of olivine accompanied later by the westward expulsion of the
tholeiite, quartz tholeiite and alkali olivine basalt. Anatolian block (cid:14)Sengo¨r et al., 1985; Dewey et al.,
Olivine tholeiite is the most abundant type among 1986., accommodated by the East Anatolian fault.
the seven different lava flows and occupies large In the triple junction area, there are field evi-
areas along the valley floor. The quartz tholeiite and dences that the East Anatolian fault cuts and offsets
alkali olivine basalt is located all along the western the thrust surfaces formed during the compression
margin of the valley. (cid:14)Yalc¸in, 1979; Perinc¸ek and C¸emen, 1990; Yu¨ru¨r,
The older olivine tholeiite of the valley floor is 1992; Chorowicz et al., 1994.. Moreover, McKenzie
vesicular, olivine- and hypersthene-normative basalt. (cid:14)1976. proposed that the East Anatolian fault cuts
The subsequently erupted quartz tholeiite is slightly also the Amanos fault zone (cid:14)prolongation of the
quartz-normative and forms blocky laves interlay- Dead Sea transform. at Tu¨rkoglu (cid:14)‘T’ in Fig. 1. and
ered with brecciated agglomerate. It contains large extendssouthwestwardsthroughtheAmanosRange.
plagioclase laths, olivine and a few clinopyroxene However, on the basis of 20 m multispectral and 10
phenocrysts. Its groundmass is composed of plagio- mpanchromaticSPOTimageinterpretationsandfield
clase microlites, olivine, opaque minerals and inter- observations, Yu¨ru¨r (cid:14)1992. and Chorowicz et al.
stitial volcanic glass. The more recent alkali olivine (cid:14)1994. have shown that at Tu¨rkoglu, the East Anato-
basalt, with the exception of the Ceylanli flow dated lianfaultdoesnottraversetheAmanosfault.Forthis
as 1.73"0.10 Ma, covers a west-wall fault system reason, we propose that the Amanos range, which
that had cut through the previous quartz tholeiitic once indented southern Anatolia, should in the pre-
basalt. Large olivine crystals with a few plagioclase sent-day situation be attached to the extruded Anato-
(cid:14)An . form the main phenocryst assemblage, while lian block. Another argument is that the Amanos
53
the matrix is mostly plagioclase microlites, olivine Range should move with a westerly component in
and opaque mineral grains in an interstitial volcanic order to open the Quaternary Karasu basin, located
glass. It is olivine- and nepheline-normative basalt. east of the range. This change of kinematics is