culmea cernei granitoids - structural setting and petrochemical data

I
Rom. J. PetroJog)', 1994, 76, p. 19-31
CULMEA CERNEI GRANITOIDS - STRUCTURAL SETTING AND
PETROCHEMICAL DATA
Viorica IANCU, Anca ANDĂR, Constanţa UDRESCU
Llst.it.ut.ul Geologic al României.St.r.
Carallsebe~
nr. 1, 78344 Bucure§ti 32
Kcy words: Granit.oids. Granodiorit.es. Monzogranites. Magmatic differentiat.ion.
Calc-alkalic composition. Majore elements. Minore elements. South Carpathians.
Abstract: The Culmea Ccrnei allocht.honous granitoids (Da.nubian Realm) are spatially
a ş~ ociated wit.h t.he polymet.a morphic formations of the Drăg1jan Group. Temporally. they
can be related to the" AssYlItic" (Upper Proterozoic) or "Caledonian" (Lower Paleozoic)
orogenic events. These granitoids form a compositc massif constitut.ed of granodiorites
and monzogranites and, subordillatcly, tonalites and diorites. The geochemical data
revealed a medium-pot.assic calc-alkalinc scrics with a differentiatioll trcnd specific to the
suites generated in a compression geotectonic medium. The Nb contents (less than 40-50
ppm) are characteristic of the island arc magmas. On the basis of the Na20/K20 ratio,
thesc rocks are assigned to 1 typc granites. They can be regarded as M type granitoids,
that i5 originating in t.he mant.le, or wit.h a mixt gcnesis - mantie + crus!..
1..Introdllction
The petrochemical characterizatioll has been maele
on thc basis of the analyt.ical data processing and the
The Culmea Cernei granitoids have been relatively
comput.ation of the CIPW, Rittmann (1973) anei la
less stud'ied up till now (Iancu, 1974,1977) and no age
Roche et al.(1980) norms, in view of their plotting on
dating has been made on them.
diagrams userul for the study of tbe granitoid rocks.
Duc to their geological relationships with the PreThe petrogenctical diagrams lIsed by us have been
cambrian formations, on the one hand, and with the
c1aboraled by different authors on the basis of numerPal eo-Mesozoic cover formatiolls, on the other hand,
ous statistical studies and analyses carried out on REE
their a~e ranges between the U pper Precarnbrian (" As-·
amI isotopes. We have at.tempted to infer the geodysyntic" granitoids) and Lower Palcowic (granitoids asnamic framework within which the study granitoiels
sociated with "Caledonian" events).
have been generateel, taking into accoun!. thc fields in
T he Culmea Cernei granitoids are cropping out. in.
which thc analytical data. available are pJotting.
the left slope of thc Cerna Valley, from the confl uence of the ema Valley with the Cărbunelui Valley
2. Geological-structural setting
to Vârful lui SLan. Southwards, they orcur discontinuously frorn und er the l'v[esozoic cover formations up
The features of the Culmea Cernei granitoids and
to north of t he town of JIerctllane.
This paper deals wilh the geological-structural' their geological setting are renJered on Plate.
2.1. The granitoid body displays a strongly clonframework of the Culmea Cernci granitoids, internal structures and relationships with lllf' surrounding gaLed shape (ca 20 km), ils outcropping area being
rocks. The pe trorh c tllÎ cal characterizatiotl is bascd of maximum 3- 4 km wide. East.wards il is delitnon forty clwlTlical analyses and t.wenty five sp ect.r"al i Leei by th e Prc:ci1l11brian rnetamorphics of t.he Drăgşan
analyscs (Tahs. 1 1\1ld "2). l\l incralogical anei pelro- GrollP, which at the linw of intrusion reprf>senled the
graphi cal sl.udi(~s carri.>d out. by us, partly rublished hos! rocks, and westwards by Mesozoic fonnations (by
JlIeallS of Meso-Caillozoic tectonic contacts).
(Iancu,1971) hav(, LW P ll also taken into accollnl. •
20
T be prlm a.ry st ructures, well represen ted in the
ee\!;tern a nd nort hern part , poi nts to a n oval-sha ped
bat holi bi c body, in it ia lly emooted, with a marked regioll a l stru ctural control imposed by h is m placemc nt
in a st re . . {ie ld ind uceel by orogenic compression.
2.2. T he regional-structural setting is bilsed bot ll
on gcolog ical mappings and on regiona l dat a . T he
C\t1 mea 'erne i grall it o id s en ter in to t he const itution
of t he basem en t of t hc Alpine Lainici Nap pe ( Be l'za
el a l., 198 8), belollgin g to t.he Lower (OI' Ex ternal)
nubi an Un it ·_ T he tectoni c d iv ision o f t.he DCillUbi Il Real m , Larami a n a ccordi ng to th e m ent io ned authors , w as co ll sidered polyplt ase by Ian cu et a l. (19 90) ,
a,; a result of rep eaterI sh ean ngs that occurred d ur illg
Lhe A us (. ria Il a ll d Larall1ian (I ow-angle s hea rings) a nd
intr a-Mioccne (generally h igh- anglc sh earings) teclogeneses , i li e b Cler es p ecia lly ill the out ermost pa rt o f
t. he D aH ubi an Re ' lm _
T he n a pp s (Su pl' age ti c, Get ic, ln f agetic an d
D il llu bian ) gene ratcd duri ng -he C reta c ous LectogenE'ses ar e t.ecto lli ca lly up rposed a n ei fo lded _
D llri ng t hc M io c ne t h y werc Lh rust toge ther
over tlL Moes ian Pl at fo rm (Ianc u et al., un p ub lish erI Ba la. a nei Ba l v ă n c§ti s heels , sC.l:50_00 0 ana
Ianc u I ă ru n~ i u,19 9 4 in t his vol. ). Thus , th c Da nubi,Ul ba:em ellt , inclu d ing also the Cu lmea Cernei g ranito ids , ullrIe rwen t re pea ted shearings along d iffe reni
d is ontin ll it.y pla nes _ T he posLn a p p e fa ult ings of t he
'ern i'l-J iu ;;ysle m fragmented t lte C ulm a Cernei granitoirls . Alo lig l!t e ,eru a V<dley Lllf'! y were int ens Iy t a tacl ased allel hifled Do th verlically (Ia ncu, 1977 ) a.m l
ho rizon t.i-l lly (Bt'rc ia, j 975 ; Be rz a , D r ăg ă ne. cu ,198' )
2.3 T ll e geo logical s tt ing aJl(I t lt e g rani toiel s I'e lations hi ps w ith t.h \ros t rock s ·'n e l' noered on la le_
In d irect rdat ions h ips witl! th ' gra n ito ids a re f rrn atioll " of Lh D r ăg. aII G roup , I'f'present.ed in t he a rea
o st ll dy hy iJ mos tl y a.mph ibol it ic s quence (am pbi bo li te;:; aud a m ph i bo l ic g n e i s s e~.), in cll.!d ing a. tel' rigene
(pbgiogneissl's , m icasch isl.s) scq ue ncc (s ub fo rma t ion ),
gr' 1111:: ricall y .-itll ated a l Lhe upper part , in a s ui e of
narro\\' a n d 10llg at.ed sy n clinal s t ruct u res; the wh ole
;; q li ne", b , 1 n gs 10 il, p re- Mesozo ic a nlicl ill a l reg ion a l
st.r ucl ul'e, wit. h t he ' ullllea c.·r l1 i gr - ll iLo id bo dy in
tll e 1 i ll gl~ (Ian cu,1 977).
A p re- Alpill P t ect oll ic CO li ac t, m a l'ked by an
<"'pil1l ,t.R trlo rplli c b la. tomy lo n it ic ZO Il '" , cro!' pillg; oul o n
a wid UI o f a bo uL 1- 1.5 kll1 , nm kc:o t he t r aI! iliu ll to fo rm aLi olls Iploll g in g Lo t.lt e L a illiei- P ă i u s 0rollP, I'\! pr escn l ' d by q ua rtzo us metap elit opsammiti c an J o Hbona l ic rocks . lVi t ll in t ·re lat ion. o f am phi b01ic OI gra p hiI Oll s rock ;; _ T wo .uUforn lat ions are ollt.lin cd , f he O ll'ho n; ll i ;Ind am p hibol itic rocks crop p in g ouL in synclil ll's ; Il ley il re situ a U:c' in il11 lI p pc r li t ho,t ra tig ra p hic
Jlo,.:illnll ;1;; aga in,; L l. lt c q Udl"Lz-f ' lds p aL lt ic aad rniea(" '()1I ::; ro cks_
On CI reg io na l scall \ t hc O r ăg~ a ll a ud
\1. IANCU et a /.
Laini ci- Pă iuş " Seri ' s" have been divi ded by Berz a et
a L( 1988) into several s ub d iv i;;ions regardeel as formati ons . Accord illg to the m entioned a ut hors the whole
sequence belo nging to the Lainici- Pă iu ş "Ser- es" in
t he st u dy a rea could p er tain t o a lower , ., car bon a tegr ap h ito us" for m a ti on_ T h e te rrigene megaseq uence of
the La inici- Pă i u § G ro u p is s pAt ially associa ted with:
sy nki nerna t ic a nd late kine m a t ic P recamb r ian granito ids (Savu et al. , 1978; Berz a ,1 978), whi ch 00 no t crop
out. in the arca pr . enled on P late ; A rsase a di orites
(bl as tomylonit.ic diori tcs cf. Ia n cu, 1977) ; numerolls
pre-Sil urian ve ins a n d dy kes of m icrodi ori tes an d microgr anodio ri tes (± p orp hyric) ( Be rza, Seghedi , 1075
a) _
Aecordi ng t o Ia ncu t a l. (1990) , Ia ncu M ăru nţi u
(1 90 0) tlte two ' g roups" - Drăgş an a nd L aini c i- Păi u §
- r preseni cont ras ti ng li tho faci a l associa tion s coming fro m ilfeas wit h a d itTerc n t geo t ecto n ic posi tion in
t he M idd e- pper P roteroz o ic. T he Drăg~ an Gro lliP
(li ke t he 1elo va an d ~J ă r u cry"ta lline rll <lssi fs ) contain s mos t ly a mphibolitil' s ,quen ces a n d ocean crust.type roc ks, whereas t h La inici - P iiiu§ Group (l ike t he
eam t ll Series ) rep res"'n ts a cO ll t ill ental n ust-typ e a.ssoeiat ion.
T h ~ primary meta.morphi slTl of t he lwo units t ook
pla.ce u n der el iffe rent baric colld itiollS: m ed ium p r l)su re - Drăg§an G rou p (l all C' u, 1974 ; Berza , Seghedi ,
1975 b); low pressu re - L ai ni c i - Păiuş Gro up (Savu,
1970) .
In our opillion botI! megasequcnces el isp lay stru ct ural a nd min ralogiea l p roofs in favo m o î a poly defo rIna t ional evolu tio n under thennal coud itio ns . p eci fic
to t he an phi bo lit. ic fae ies, fo l\owed by dynamot h _rm al all rI dYll ami C' reacti vatiollS a!. t lte grcc nsch ist facies
I ve i.
The COlIJlTlon evol ut ion of the two "gro u ps" of format io ns a[te[ he emp lac ment of the Cul mea Cern ei
g ra nitoids and of the intcrmcdiary rock vein s , is proved
by : t be' transition' of the t wo gto u pS, marked by
ch !ori t e, ep ido te-alb it. , sti lp no m ela ll € bearing b lastomyloni t es (Ian cu , 1977 ) , whic.h in fact poillt.s to el preAlp ;ne tecl.o ni c cont.act; the retrograde dy na m ic ada ptat ioll to tit' p,ree nschi::;.l facies I' vcl bo lh of the polyI1lcl.a lllorp ltic roc ks of t!t e Dt ă g~a n i\n d Lainici- Păiu §
!)I'O UP S i;.ud of t he il so ciat.cd gr il lli toids; tI! rnet a nlOl'p h is m of t he ITI re rec 'll t vein rocks whi ·h a 150 too\.:
place a L t he grcc nsclti 5ts facies lcvel.
2.4. Rclat ioll'h ips o f t. he g t'a ni loids wi t tl th e hosi.
rocks prove t.heir all ocht ll o nol ls fe a ures, OII the o ne
hand . a 11 d the ex istellc e of a reg i na l st ruct ural cont rol
imposed by a SU bsNIIl cn L del'o nncl hona l c ve!lL of th e
hos t. roc ·s , alread } l1Ieta mo rp hosed M, t lw leve l of t he
a mp hi boliti ' fa cies , on tl!e other h an d.
\VC slt ali pl'e -e llt. briefly ftc ld eviclen ce wh ich is
111
fa vou r Qf ti t(' a ll Dc lt t ho ll C)US chara cter . pos t.-
CUL M EA CER.NEI GRANIT OIDS
m t amorphic (post M I , M 2 ) but syn chrono us: wi th
a more recent " o rogeni c" (D 3 ) even t, of th e Culmea
Cerne i gra nitoids:
- existe nce of t he sharp cont ads of t he g ra nites wi t h
the roc ks of t he D răg§an Grou r and the secant charad er of th e apli tic a ud peg rnatitie veins in com par i.-o n
with the str ucl ures of t he surro un d ing met.amorph ites;
- high frequency of thc xenolit hs a nd sep t a of
the metamorp hi c rocks as we ll as ()f t h - agmatiLic
migma ti tes with a ngul a r I"ra rrments of me. o rnetamo rphi c rocks, an ei scarcity of x no liths of basi e magmati t s ~n d m afi' schli rells ;
- ex istenee of a spedac ul a r migmatie Ru r 'ole, on
an outcroppi Jlg a roa wid e 2-3 k m , includ ing mixcd
roeks (granit.i . 1 ucogran iL ic leu cosome an d pal eosome) wit h s tr ll ct. ures eith r p e lldoconfo rmab le wit.h
t he m eta.morphi c foli a t iolls (" [it-pa r-lit " ), or lInc.onform , bIe (secanl.) with t hc m :.
- presene ' of the eITec s of a t hcrrn a l e.vent (M 3 ) sup rpo ed 0 11 t h M 1 , M ~ ~l r u c t.u res an d patagclleses of
th e D ră g~a l! G ro up . an evellt whi ch a n ha rd ly Le dctec t a ble ci li t o t h ·' i80fa cia 1 cha rac t r of f!le t helln al
contact pa ragCIP cs wh ich co nt,a in: silli m a ni t , l1l11Scovite , gamet, chlorit.o icl (in lnicaschi sls and paragnc·isses) ;
- reg io na l s t.r uc t ur al co nlrol ill ust rat ci by :i nlrusi on
of the grallit i, bo cly OII' r u la i cliscon t inui Ly 11sc rib d in it llIcgu allticlinoriulll stru c ure; pse udoeon fo rmity of m igmc t ic neOSOI11 in res pect wi t. 1! I.h "": S:!
reg iona l foli a tio n ; oc cur rencc of so me g ra nit ic a pop hyses in t h ax ial zo nes of BJ meso. cop ie fo ld".
2.~. S Lrll el ure of t he C ulmE'a em c i gl"a ni! oid bo d;;
re fe rs both to t.hc g ornctry of t lw wh ok hody, rc pI' csCIILcd on the ma p ( P la te ). <Ind l a the intern a l sl, ru cture. Th la lte r, altho llg h (" mp lcx, C;1II !le h;lI·,l!y CIIIph cvized du 1, 0 t he low dpgr('c of o ll t cro IJ Pill g ;111<1 t ll('
red ucpd dcgrE" of access ihilit y o r t h " zone . At t hc massif .. ca.l ,on ca n ob .. e rv,' an as '1llI11pl,ri ca l s(. ru cL ure
wi h th e eas l.CrI l bord er w0. lI- prcse rvcd ( th W ' Le rn
par I. is not ohser'va bie , d u (.0 lo'cf o nic ac(" id('11 ts ) a nd
a te rmin a l no rt bc tll ZOI1t' , II<lrrOwer . wiUI IlUnlcrOll :;
apoph ys ,s, a rterit.ic a nd agm it it ic mi gm at it.es . T he
Il et.am o rphi c
p t a a lld etlclav s are fr ~q uP ll t l y found
in the east.ern and nor t herJil Pi\l" t : they a re hot h banded
amplliboli t es and sJightly hor nfc l. cd pl ag iogneisscs.
Th e mass if is rnost.l y cltar ac terizcd by rn ass ive
s t ru ·t urcs . g ra nod iori tcs el carl y preva ilin g.
'[0wa rd s t he n a rn'inal zo ncs il. lwco llles to nalili e, wit h
mane schlicrcns an d xe llo li lts of co nsdng uin co us ll1agrnati tes , \l sua lly more has ic (arn phi bo li c d iori Les.
rarel y wi l h p 'ro :-: nes ). A ls in t he rna r!;in;J 1 zon s
(eastern a n d n rt h rn) , m icrogl' allu la r lip lo ;aplil ic fcl,cies OCClIl" , as a res ul t. o f I.!te magma eoo ling prac sses ·
In t he "C ' ll Lral" zo ne (left si de of t he (:('rlla Val ley ), ovoida l "Jl uclei" are t.o be found, evident. in
21
t,he ll eld hy graniti e rocks (rnonzogr a ni tes , a cc. to
Ri ttrnan n no rm) bearing biotite and poikiliti c. (pin k)
potash [elel. par (up to 2-3 CI11). Monzogr a lli 'es , alt houg h do no t present visiblc cont.acts with the graIlodiorit ic roeks , seem to rcpresent subseq uent in t rus ions wit h in t he gra nodiori t ic calc-alka line series (Fig.
10). T hey have CI. corresponden t also in some vein s
or apo physes cross ing the granod ioritcs (which locally
c1 isp lay magmal.i c flow t exLu r ).
The strucl.ur al as pec ts Clnd rel ationships bC'I,WCCll
diit rent p · t rograp hic ty pes poiuL ou L the im pc rcC'ptible pass ing from t.o na li tes t o granod ior i cs and tl tpclear contact (d isco ntinui ty) bctween mor<e bas ic gfilnodi ori tes Cin d xenoli ths , on lIl ' one ha nd , itud g r;:lll o d i o r i t l" ş a nd m om~ o grani les ; on t he o her ha nd. Ail
t his s lI' gcsts the ex istc ll ce of a composite bo ci, 'S it hin
which t he ou t cm ost pe trographic terms can also r<e presen t dilfe rent stages or moment s of int rllsioll elurill g
a long evoluti v process, wlt n a. ll1agm at ic diITercnt iat io n was poss ible by fr a cti ona l cry s t a ll izalio ll, inclllced
by the e xisLence of t her m a l g,ra di en ts (g rad ual tta lls:,
t io n fro m gra ll od iorites to I oll a li t s).
u imea Ce rrt ei grallitoids include, hoth il\s idc CLnd
in Lh e margin a l ZOlles, genetic a ll y associat.c d vcins of
arli tes , mi crog ran ites an ei rnicrogr a nodiori te2 (± por·
phy r ic ) as w(' 11 ;:tS r egm a li t. s .
Pri m ary st m c/.u r s, ('or r la t ahlc wit h th e e rnplaceIll e n l. of t1H. l11 ugmas inl.ru sion, can hc rarply OI )sP' fveel,
oil e 1.0 th t: oU Lcl'o pping conditions and thc erI' ci s of the
s u pcrp oscd , loca lly repea t.ed , dd o rm at io llai pro ccsses.
T it " m assi v<,:, isotro pe stm cl ures Ipa rl y predo m iIl ell e . 111 so rnc eases pl a na ry ori IlLa tio llS o[ tit prisIll.'l l ic m i nera ls ( feld spars , am phi bolcs ) Ol' of t.h e ll1afic
Illin cra ls scldicren (bi ot ite , Cllllp lliho1cS) have b 'e n 110IceeL T hese plana ry lis po. il io ns (now 1, xt lI I"CS) ill'e
j1 tasi verti ccd in t he viein ity of thc l' a,; 1'11 contact, 10ca lly rO rl11ill ~ an a nglc with t h co nt,ac t pla llc. JII t.h ,~
cent. ral zo ne, tiiC Inassive, C'qui g ra Jllllar (in g rC\ llodioril, :. ) 0 1' inequi g ra.nul a r (ill l1lollwgranit e ") strl}cl.ur-es
a re prevailing ; loca lly joint.s \\l lt ich are iik> ly t.n ile primary (of cooli ng ). wi th a sub lI o ri zo nl".a l di s p o~ i tio l l , are
a lso obs rv d.
Prirnary st. ructural aspect s of inleres t ;ll" ~ presl' rv ed
in Lhe llor t ltern ., a pex" or te rminal ZOIl(' wh ere t he
all1phibolitc all g ula r fr ag rnellLs (h ost roeb) Il a ve I)Ce11
Lur 11 ·cI ro Ullrl anei . hi ftecl IIp\\"ards.
Th e pr ima r...- stru ctu res fr o iil I he ll1arg ill rt! ;': Ql l('S, likc
t hc rrce t of t h " sLwrl ura l co nt rol" 01' LI]!' " pop II Y;;('"
i11 th c lIligm a t ic au reo le ;1I1c1 t.!t(; r; lollga t io ll (r];lll r' lling ) of t.h ' s "pL<'l Il' ra lH wi t ll Lh . co ntele! as \,: (, 11 ,lS
t lt c plall ar y : t n I '!,lIre: of !.i l<' 11 0:=<1 rock :; po ill l o ui lil "
gra u i l oidş illtr u:;; ion unrkr st r '~ .
. cco/J'!21 ry »l fll c l l/ fes , slI], ·cq ll ont. to til P Ill cl~l n;l
coolill."·. g iv . il "gllc iss i('." o r " bla"tomylo llit ic"' as pect
t.o Lit cg ra llit o id roc ks. e,,; p ' cia lly 0 11 t hc eas lc rn lllil rg ili
I
V. IANCU et al.
2'2
Table'
Chemical composit.ion of the Culmea
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
3:3
34
35
36
37
38
39
40
Sample
94
2002
2059
170
92
18
247
2391
82
2010
2416
M I- 1
21
84
75
2124
76B
26
172
171
2067
2522
2467
2051
100
199
149
2080
2139
103
147
2126
3
2022
119
2058
87
8
2127
198
where the dynamic metamorphism which marks the
pre-Alpine contact with the rocks of the Lainici-Păiu§
Group affected the granitoiels, too. These superimposed structures proved to be generated by: subgranulation, ductile dynamic deformation and cpimetamorphic blastesis in a shcar zone. Thc late elynamic eleformation anei the retrograde mineralogical adaptatioll
wcrp common to the Culmea Cernei granit.oids, the
hos! rocks of the Dri:igqan Group, the Arsasca elioritcs
aud tlil' rocks of t.he Lainici-Piiiu'1 GrollP. They also
Petrographic Type
Grani t.e( monzo)
Granite (monzo)
Granodiori te
Granodiorite
Granite (monzo)
Granit.e (monzo)
Granodiorite
Granodioritc
Granite (monzo)
Granodiorit.e
Granit.e (monzo)
Granodiori te
Granodiorit.e
Granite (monzo)
Granodiorite
Granodiorite
Granodiorit.e
Granite (monzo)
Granodiorit.e
Granite (monw)
Granodiorit.e
Granodiorite
Granodiorit.e
Grani te (Illonzo)
Grano dio rit.e
TOllalite
Grallodioritc
Grani t.e (monzo)
Grallodiorite
GranoJiori t.e
Quart.z lllo11zodiorite
G ranodiori tc
C ranodiori t.e
Tonalite
G ranodiori te
Granodiorite
Granodiorite
Quart.z monzodiorite
Porphyric granodiorite
Porphyric granodiorite
Location
Cerna Valley
Capra Valley
Cerna Valley
Cerna Valley
Cerna Valley
Cerna Valley
Arsasca Valley
Dobrota Valley
Seaca Valley
Palt.inei Brook
Dobrot.a Valley
Cioaca frasiuului
Cerna Valley
Seaca Valley
Cerna Valley
Arsasca Valley
Cerna Valley
Cerna Vallcy
Arsasca Valley
Seaca Valley
Cerna Valley
Capra Valley
Dobrot.a Valley
Palt.inci Valley
Cerna Valley
Arsasca Valley
Cerna VaHey
C e rna Valle)'
Capra Valley
RÎm nn ~a Valley
Milcallul Valley
Cerna Valle)'
Cerna Valley
Pal tillei Valley
Cerna Valley
Cerna Valley
Seaca Valle)'
Cerna Valley
Arsasca Valley
Arsasca Valley
Si0 2
76.03
74.32
73.26
72.30
71.97
71.81
71. 69
71.68
71.54
71 51
71.46
71.20
71. 15
70.50
70.31
70.24
69.87
69.46
69.40
69.39
69 ..39
69.13
69.07
68.92
68.75
68.20
68. 17
67.67
67.13
67.10
66.51
66.00
65.31
65.23
Al 2 0 3
13.85
14.83
15.12
15.70
18.13
14.89
16.14
16.19
15.73
16.06
15.43
17.38
15.08
15.81
16.65
16.74
16.49
16.91
15.4.0
15.90
17.23
15.57
14.91
16.12
16.68
15.83
16.50
16.58
16.63
15.00
17.20
18.24
17.76
13.75
64.'10
17.'10
64.02
62.8.5
58.70
69.50
68.80
19.38
18.13
19.83
17.20
17.08
affected the pre-Siluriall dyke rocb, withou!. always
dist.roying their primary strudures. In tbc maximal
deformeel zones nearby the tectonic plan e, tlw dynarnic
ultrametamorphism deterrnined a strong cOllvergcnce
of charact.eristics of the b la.<;tornylonit.es [orrned Oll
rocks with similar petrographic cOlllposi t ioll.
The brit.tle defo rmations (catacl as(~s, etc.) in t.he
westel'l1 part of the massif havc bccn obviou;.;ly g<'!:Jerated by Alpillc movcmellts.
23
CU LMEA C ER NEI GR A NIT OIDS
Cernei granitoid rocks
Fe20 .,
Fe O
0.97
0.27
0.17
0.80
1.05
0.97
0 .79
0.60
1 .03
0.65
0 .70
0.90
2.6 4
1.35
1.28
0.59
0.90
l.7 8
1.13
0.S7
1.11
0.(;2
0.:30
1.05
1.42
0.90
0. 94
1.26
O.G4
1.40
1.8 . 1
LaI
1.13
1.15
1.0 5
1.26
1 .1_
.,
r,
0 .72
0.80
1.12
1.23
1.61
1.6 2
0.87
1.33
1.47
1.36
2 .0
2. 3
1. 70
1.56
1.55
1.11
1.8 7
2.:31
O.91
2.42
J .97
.l.41
1.96
1.4 4
1.6 ]
0.9:3
1.8 0
2.09
0.83
1.10
2.34
1.55
0.41
1.83
2.2 8
:3.18
2 .36
1.86
2.56
2.8·1
1.6 l
1.70
157
MilO
0.02
0.03
0.03
0.02
0.03
0.02
0.01
0 .02
0 .15
(),OI
0.0 5
0.02
0.03
0.01
0.0 5
0.0 3
0 .0 0 .0.5
0.0,1
0.01
0.02
0 .04
0.05
0. 0 2
0.02
0.01
0.05
0.02
o.e)!
0.04
0 .06
O.O,i
0.0 2
0.112
ll.O6
O. O!
O.OS
Mg O
C aO
1\a 2 O
1( 2 0
T i02
P2()5
Ih O+
0.43
0.20
0.4 1
0.64
0. 43
0 .41
0.65
0.7U
1.27
1. 51
2.3b
2.62
1. 7 8
2.04
2.2 9
2.25
2. 55
1.80
3 .11
3.41
3.91
4.30
3 .07
3.S9
:3. I ii
0.10
O.,"')
1.00
0.47
0. 50
0. 55
0.97
0.87
1.0 1
3. 6 1
.4.03
2.20
2.10
3.90
3.15
2.45
1.36
3.5:3
0.03
0 . 12
0.04
0.05
0.08
0.12
0.14
0.09
O.}(j
0. 17
3.88
1.08
0. 56
0.8]
ZAG
4. 19
3 .28
·1.57
3. 3.')
3 .6,1
3.2 1
1,47
I ..UJ ...)
O.G·l
O.U :)
0.'1 5
n. i5
0.21.1
0. 21
0.1 9
1.0.'5
0. 6(;
0.3.S
O.(i 3
0.19
0.63
o. sn
0.42
0. 9 1
0.67
0.83
l.O G
1.32
l..31
1.31
2. ,12
1.32
1.0 8
1 . 0".)~
1.1 2
O. S5
1.11
0. 6 2
4. 6 1
1.97
1.1 fi
3.4G
3.0 I
2.0:!
2.29
2 .75
3 .05
3.06
2. 50
:3.74
:3.9.1
3.60
,tJ 7
2.23
.77
3.90
2. G2
2 .88
2.6 2
2. 8 0
2. 5 2
2.81
3.41
3.17
4.40
2.10
3.30
3.42
459
2.'23
.5 .5 1
4.0 5
1.20
3.5{
2.fi4
·1.50
'1. S8
:3.37
1 .0 6
3 64
3 .85
3 .S2
3 .7.5
3.7.1
2. 55
5.25
3.54.
3.61
3.'14
3. 5 J
:.l.fî.j
3.91
'1 . .)- ,.)c
:1.,14
1.04
1.:37
3.23
4.22
2. ,1:')
1. 5 2
3.34
2 .5 5
2.52
2.0 5
2. 8:3
2. 50
3.77
1.30
1. 8 9
2.33
3.3,1
2.3fi
1.<15·
2.H
J. tn
2.71
2.'17
3. 23
1.57
2.27
1.89
2.55
2. 64
2.17
2.81
J. 20
1.80
3. P et r o che mical data alld gene ti c implicatiolls
Severa! d iagrarns ha\'(' b ell obtain eel on t hc ba.s is
of Llr c mcnt.ioll cd pclrograp hi c data a mI tir , 3yaila bl
aJla.lytical data (Tahs. 1 a mi ~ ), which ma ke possil)l e
signific311l clr a raclc riz <:llions . T hus Olt the varialion JiagraJIl of al·alini t.y after Wrighl (19G9) t h ma in jieLrogri..l phi c l.ypes cOll st it u ill g t ir e C ulmea C 'rn ei m <.lSsir fal I in t ire fidel of tir ca lc-a lkalil! f rock s, CXCf' p l for
1. \\'0 sam))1 's wlticlr plo t il! l ir e fi Id of tiI ' alkalilt c rock;;
( F ig. 1).
-
0.28
0.39
0.20
1.1 6
0.2\
0.26
0.22
0.2:'
0.2 7
0.17
0.2:'
0.24
0.2.3
0.28
0. 26
0.24
059
O.SO
0.35
0.,10
0.59
0.35
._ I
OT
0.48
0.40
OA6
0.51
0.5 4
0 .6'1
0.5 2
O.4,j
0.:33
0,45
04 7
0 ..57
0.6'2
0.33
0.4 2
.
O.OR
0.08
0.07
O.U7
0. 25
0. 14
0. 11
0.2 2
0.18
0.08
0.08
0.09
01 4
O.~. "'l
0. 05
0. 22
0.07
(1.21
0.20
0 , 12
0.08
0. 19
O. l (j
0.27
0. 02
0.31
0.1J
0.3 j
0.30
0.12
0 .08
11 2 0
n.24.
0.20
0.17
0.11
O.IG
0.31
1.14
O. 8 U
1.2:3
O. 7S
0.0 7
0.7 3
0.96
1.1 9
~)~) . 50
0 .19
0 .15
on
1.09
1.2G
1.1 5
0.5 5
1. 0G
0.8 5
1.69
0 .17
l.:t7
2. 8 0
l.l:l
1.09
0.10
l. lfi
1.1 5
'T'otal
]00.61
100.3 7
99.70
100.31)
102.54
100 .0.5
9').75
99.6.5
100.00
I OU .2 1
~) 9.4 5
lUOS7
!) ') Afi
0D 7 5
9 9. 5 0
9 ~. l 5
lflO. 31
9 9 .5 1
!HJ.l 3
10 0 J)7
0. l.3
9 9.:19
1J.1J (j
~)~) . 1
99.G 8
J 1l0 .0 9
9 '1 . 1 l
IOO. S
l UO. 9·2
1(1).10
100.(1)
9 D. 5 U
99 .0 8
9!J .28
l()O.6·2
9 9 .8J
0.11
0.23
0.35
0 .2,1
0. 2 3
0,2 4
0.20
·0 .13
0. 33
0.27
99.92
1.1 6
1.4(j
:) 9.4R
99.05
% .7 4
1.1 5
99. 52
1. 3G
O.:l9
I
U. 28
0.20
T lie Q AP d ia grall1, aft<.' r Strec keisen (19 r-i 7) (F ig.2)
shows thc plotting of mos!, of !te sc\lllplcs in t.ltc fi elel
of granodiorites and monzog r(l llit.es , and s ubordiliat<'ly
in thc fid el of tOllillit es and mo n wd io rites .
On t he diagra rl1 AbA nOr. lI :)('d hy [( 1'ell1aa ( 1\)(j5 ;
a]'I.' r Huseh ancl !\(orea u ,lU82), I Il!' san rples aUi:dysed
by LI S (F ig. :3) >Ir' obviollsly g r () up eJ bct wr c/I [h c
u ' (und er it pre.'sure of 5 kb).
C Il[' \'(>!) of 700 atld 750
T ll e samplcs ar" rl cad y ind ividualiz.;eI :ci 'cording (,0 th c
ri clds of acid (A) clild hasil (B) ro ·k·. be ing [o cu scJ in
CI Ilnit a ry fidd of i il le rll1(~ di a ry ro ks \\' hi clt belong Lo
a ealc-alkalinc se ric~ (set' Fig. 1).
V. IA NCU et al.
24
Table 2
Trace elements (ppm) in the Culmea Cernei granitoids rocks
No.
1
2
3
4
S
6
7
8
9
10
11
12
13
14
15
16
n
18
19
20
21
22
23
24
25
Pb
Cu
Ga
Sn
Ni
1<1
19
18
11
16
15
22
19
17
21
14
15
23
22
21
21
20
19
19
20
17
18
2.0
2.5
2.0
2.0
2.5
2.0
2.5
2.5
2.0
3 .0
3.0
2.0
3.5
2.5
3.0
3.0
2.5
3.0
3.0
2.0
2 . .5
3.5
3.0
2.5
3.0
4.0
4.0
15.0
3.5
3 ..5
4.0
6.0
5.5
5.5
4.5
13 .0
5.0
9.0
10.0
15.0
11.0
36.0
11.5
11.0
5.0
11.0
280.0
10.0
5.5
10.0
6.0
8.0
16.0
19.0
6.0
6.0
9.0
5.5
4.5
5.01
200
5.0
11.0
14.0
25.0
17.0
40.0
26.0
13.0
6.0
2\.0
17.0
13.0
6.0
2 \.0
25 .0
11.0
18.. 0
12.5
38.0
7.0
13.0
14.0
12 .0
] 6. 0
13.0
15.0
19.0
n.o
7.0
33.0
5.5
18.0
13.0
13.0
5.5
190.0
16.0
11.0
30.0
22
20
18
Co
4.0
6.0
2.0
5.0
5.0
5.0
7.0
7.0
6.5
3.0
2.5
8 ..5
11 .0
10.0
7.0
9.0
10.5
12.0
2.0
10.0
37.0
11 .0
11.0
14.0
Cr
1.5
4. 5
5.0
2.5
6.0
6.0
9.0
9.0
9.5
8.0
8.0
5.0
17.0
17.0
2 4 .0
10.0
15.0
13.0
15.0
4.0
20.0
550.0
23.0
9 .0
23.0
V
Se
Y
Yb
La
Be
Zr
No
Ba
Sr
3.5
14.0
22.0
17.0
21.0
23.0
30.0
38.0
42.0
28.0
30.0
16.0
:38.0
60.0
44.0
32.0
405.0
42.0
60.0
18.0
42.0
92.0
55.0
55.0
76.0
2.0
4.0
4.5
2.0
4.0
4.0
5.5
6.0
5.0
6.0
4.0
2.5
6.0
5.0
7.0.
5.0
6.5
6.0
12.0
2.0
5.0
22.0
11.0
10.0
17.0
10
22
12
10
16
15
13
14
1.2
3.2
1.3
1.0
2.2
2.1
1.6
1.2
1.5
1.8
1.0
1.0
1.2
1.2
1.8
1.4
1.8
1.3
2.2
1.0
1.2
1.7
2.7
1.7
2.9
65
1.2
4.0
1.3
1..3
1.9
2.0
2.3
2.5
2.0
2.2
1.8
2.4
2.0
1.6
2.0
1.9
2.3
2.1
2.2
1.7
1.8
1.9
2.2
1.9
2.8
70
100
240
48
150
130
180
1.50
145
265
75
85
230
330
210
10
20
800
450
700
900
700
600
780
520
470
600
560
630
290
500
.570
570
650
600
550
1000
550
140
650
600
700
160
160
300
600
150
150
330
460
220
380
260
260
420
500
300
310
230
450
350
1000
250
180
440
500
560
11
14
11
16
13
13
16
14
20
14
20
10
13
20
26
19
36
30
30
30
48
46
37
30
46
40
38
40
46
36
45
38
40
50
30
30
30
30
30
30
30
no
230
24,)
14
10
11
15
10
10
10
12
10
10
10
10
15
10
10
10
225
10
95
85
155
250
210
:l!5
10
1.5
10
10
13
10
foI' rlu rnlb er of s'tmple see T aole 1.
Q
SiOz
70
60
50
40'------,--,----.---;.-,,---,...,-.,.-..,---,.....,-,-...
,
Fi g . L
4
Di"g l'
' Il
5 6 7 8910
ar tlte alkalil1ity
vi-u'iation
IA (Wrightl
"n.er Wri " h t
(1969).
A
The used diagrams helped li S . o e,·tilllate he g(>()dynamic backgl'ound of the Culnwa C ' rnei grallitoid s
that can be infcrred frol11 the diffel'cntiat.ioll t.rend of
the samples p lo tting on il. AFtvI Jiagra rn elaborat. ci by
Irvill c and Baragar (1 \) 71). Acco rdillg 1.0 P ct ro eL a l.
(1979), the calc-alkalin e tr nd , disposrc! about perpe ndicular to th c F M sid e , points to il. generat ion medium
spe 'ific to a co mpression geotec tonic context (Fig. 4).
In tltis co nLf'xt the calc-a.l 'alin e s uite:> silow differenl
trends in relat.ion to t.he alkaline ones il.nd tlle oceanic
I
(JA l' liitgram (SI r~ckeiscn, 19fi7) , Hil. ~ malln 1l01'ms.
11 STallilf:s; 2, grd.nodiorit c~ ; 3, tonal.itcs; lI: quart.z o10nzocli-
Fi ", . 1.
orites .
thol e ~ ites .
.N I\: cliagra.1ll (Fig. G), aft.el' Lameyre and Bowden
(1982), display.· the sC\mples faJling below fiO % K,
which makes possible th e charac tr: riz a tion of the Cul-
25
CULMEA CERNE! GRANITOIDS
mea Cernei granitoids as medium-K granitoids within
the calc-alkaline series, with in which the trondhjemitic
rocks are "poor- K rocks" and the monzonitic rocks are
"high-K" rocks, as rendered in Figure 10. Such delimitations are clearly influenced by the position of the
granitoid generating zones in relation to the Benioff
plane during t,he subduction process. A comparison
between our d at a and those used by Lameyre, Autran
(1980) for the Variscan granitoids in France points out
the plotting of th e " lllcdiUI11-K" granit.oids behind the
tonalitic line (101\' h:). IIH'l""fore towards the continentai area.
An
On the basis of the analyses for minor elements (Tab.
2) represented on the diagram in Figure 6; the C ulmea
Cernei granitoids could be charaderized according to
the average contents for Sr, 13 a , considering t he average values of the standard p;ralliloids (Kraft, Schind ler ,
1961) .
K
... ---......
---" ....
C
~-
....
:.t!...
b-ig. ·5 . C N I\ d iag l"iull (Crc 'luency isulillf'" :J, 10,15
"'4A~'·
.a.
..
.. . .&4
---,
I
0
ii.ne! 20 %) .
_:,.-
.1
Or
Ab
F ig . 3 - A bAnOr diagram (Kleeman, 1965) for T, P inttervals: P = 5 kb; b'Tan.i t oids+rhyolitcs field (dotted line). Superposcd , acid (A) and basic (8) rocks fields (after Hw;ch,
Moreau, 1982). Legend of symbols as in Fig. 2.
F
TH
/'
/
---
CALC
..... ...----;6
....
/
",
/
....
.....
/ .1:"
'/ ~
tA
..
0J .
e
~
10
10
sn
200
SOO
ppm
)-/'....-
/
./
",
./
l'ig. Ii - Diagram of comparisoll of I Ite l r ac" e1 CIlH'1l 1S (1'1"")
cOllt. <; nt.s in lhe grallito id rocks of tII" Cu llllea C ernei mas,if
wilh t.he average values of the t.race elemen t.s of tII" s landard
ALC
+
granitoid rock, (afler Kraft. and Schindler. !9()!).
:~
./
A
Fig. 4 - AFi\1
di,,!-\ r;lIl1. ['''I;c"d
i\.'
in [Ci)',. 2.
Sr and Ba variations (Fig. 7) in comparisoll wi t h Ca,
Na and K point to a posit.ive Sr correlatioll wilh Ca.,
V. I A Ne r et al,
26
and of Ba with N a and K, although the variatioll trends
are relatively less obvious.
.
Se, Ca , Cr, Ni and V variation Jiagrams are presented in F igure 8 in correlalioll with Mg anei Fe (total); lhcy poinl out an obviollS positive eorrelation of
Cr and V variation simultancously with the variation
or (Iw Ilwnt.ionccl ma.ior ci 'Illt'nts.
Ppm
%
"
l>.
"
4
1
.
" "
",,'" ... ·
" ..
" ·.. ·
··
"
@
ppm) of the Culmea Cernei grallitoids falI in the fie ld
of volcanic a rc magmas, which proves to corrcs pond
with the main petrochcmieal a lld structur al data.
In our attempt to speci fy the gcnesis of t he magmas
which yieldeel the Culmea C ernei gmnitoiels we uscd
the Na 2 0jK 2 0 Jiagram, an r C happe ll and Whi te
(1974), according to wh ich o nc can diffcrell ti a te r Lype
magmas generated by the a natexis 0(' th e magmatic
rocks , and S ty pe ' magmas gCll' rat.e d by th e a naLexis
o f t 1\1' sf'd i m en l.in.> ro, ks.
1o'G!)
.
~
..
... . ..
.
"
5
4
3
..
.. ....
l>.
"
~
........" ...".."
..
..
K0
..
..
l>.
4
~
..
.
"
"
4
. . " "... ..
.. ..
6
7
a
~
. ..·
..". . ·
"
..........
..
.. ..
•
"
280
800
600
·
.
400
200
,
..
10
"
13
o
...... ..
o
20
10
..
. ...
~
.
". ;'6
A
®
A
"
•
..
40
. ........
........
A •
~
10
·
.'
ti
A
..
r
..
..
A
....
j, ...........
A
A
..
..
..
(j)
1&
80
L>
....
A
14
A
1/3 (Si. K) - ICo+ Mg)
B
60
.... .... ..
..
~•
10
11
.
.A
11
1/3ISi.K)-ICo.Mg)
On thc Nb-Si0 2 diagralll in Figure 9 (acc, to I'f!arc<'
anei Galc,l977) thc contcnts of 1 b (Ies:; than 40 - GO
20
A ' A
..
.
12
·
.... ........ ..
·
.
®
..
..
9
10
A.
....
~ .
. ..... . .
.. .... .
..
1000
. ·
.. ·
V- A._
fo
®
400
@
.. "
..
A~ ~
..
4
... · ·
2
l>.
~ 350
200
..
®
.. ...
"
400
. .· ·
..
• @
600
. ... . .
.. .... ·
..
..
..
1000
ppm
20
"
800
l>.
@
I,'ig.
x
,"'c.
('u. ('r.
\i. \'
\';LrirdiLl!l \"f'r:-'II:"
13
40
CULMEA. CERNEI GRA.NITOIDS
27
It is of noLe an obvious concen f, ration of the study
samples in field "1" (Fig. 10); they represent " igneolls"
granitoicls, called by Ishihara (1977) "magne tite series", based on mineralogical criLe ria.
Further argurne nts con ce rn ing the genesis of t. hc primary magmas which yield ed the C ulmea Cernei grauitoicls were provided by the elaborat ion of Table 3 whi ch
presents for comparison granitoids of type r a nd S belonging to magma tic seri es described by D idie r eL al
(1082) anei H ussein e l. al (1982). A compl ex argumental.ion m a kes poss ib le a more vcrid ical g<'n e tical
chararlnizat.ion tltal Cil n l"I'pl a.ce t!le la ck of n l·; I·: ilnd
i"nt "p(',; ;1llaIY';I'';.
SOO'-------------~----------~
Within plat e
magma.
100
E
Cl.
Cl.
~
10
~•• ~.
1·
• Volc ani( arc
mag mas
e ..
sItown in Table 3, Si0 2 =67.55 per cent, Na20=3.76
per cent., CaO=2.90 per cent (close t.o the value 2.97
per cent. give n by Chappel and White), K 2 0=2.56 per
cent. Furtherm ore, t.h e re is th e ulliform variation of
th e minor clelllellt.s ill reia ion La the differentiation
index.
In more rec ent pape rs, e.g. Didier el. al. (1982), a
ge ne tic classifi ca tioll of the granitoids is proposed int.o
two maill types : M- coming from the mantie or mixed
material and C - ar crustal which, in their turn, can
be of two types - 1 alld S - according ta the origin of
the primary mat erial whieEI yielded them.
T a king int.o account. the exis tence of the basic magIlla l ic cnclaves, as well as the more obvioliS basic char;ln('[ ( to nalit es ) and t he promi ne nce of the microgranIIlar s r uctures in the marginal zones of the body and
i II sOll!e xenolilhs, one can aseertain that. the Culmea
('<'!"Il ci graniloids are of t.ype NI (ace . ta Didier el al.,
1~)8L), th al. is t.h ey o riginale [rom lhe mantie ar erust.
+
ma.Ilt.Lp.
1.'l!rt.h ~ r
58
60
62
64
66
68
argu rnellt.s in t.his respect are: COll1l11on presor hornblend e in granodiorites a nd trondhjemitetOllalit.es, the conte nt of biotit.e less than 10 per cent,
1'11'1l1elll.s specific to the granodiorit.es from magmas
original illg from m a n tie material.
Q ,\ P diag ram ( F ig.ll) elabo raled by Lallleyre alld
Ilowu e n (1982) was llse d in vi e w of t.he dirrerclltiatioll
of" I.he " g raniloi J series" (gem'rat.ed eit.her by dirrerCIltiatioll fr om llHll1 t1 magmas o r by 'r ust al fu sion).
Fields:2, :3, 4 ( F ig. 11 ) illustrat. ·, t.ll ~ va ri a tio ll trcnds of
t hi" calc-alkalin c plutonic sc ries, ali· the sall1pl es stuelif'd :;lto wing a variati.o n t.re nd given by "medium- ]("
g ra nod iori tes, within which t lw higll esl acid terms of
dlrre rl'nt.iat.ioll arC' rcprcsclll.I'd hy I.lle m o nzogranites
rrom t he ceutral "nllc!('i"'.
70
('{lrI'
.,
5
4
3
Q
2
I~
2
3
4
5
6
Accordin . to T a ble ~{ Culmea Cemei g r;mitoids,
conside ring t1w fi eld relationships a nei pet.rographic
prevalc nce (fig. 2'), ar ' qui te ·Ios ·' to 1 ty pP grelllites . T he mi nera.logical eri te ria. poin t ou t a prcva leu re
of tht' magn tti lf' no rmati v" valtl<' in t.h· ho rnb lc nd, '
grani toils alld sub o relinat.' ly in thc bioti c g ranifOid :i .
as w'lI as il re lat ively high colom ind ex: lI. Ci . 1\111111'
d ata a re in coa ela.tiol! wilh Il low co nf CIl L of ;l("f", · .~ ·
sar)' min e ral s a.nd Ih e Ho rmal \',du es in rninor e l ' 1Ij(' ll h
In chcll1i cal rl'~pcct. , tiI!' ('ulm a Cernc i gra/liloid ~
also I)I" CS(' Ill. "i lll ilariLi('~ wit.1I t.lle 1 J' pC g ralliL c~. i\ ~
p
A
'·ÎJ.; . II
"ltlliin g or II}!'
l~.-\I · di<1 ~I 'lI11
C ' ldllll'il ('(TIWÎ
(aflI' !"
grilllil(l i,l ...
(III
Lamc )" .. /; , !::lOII" leII, 1~1 1i 2).
tiI!'
I
v.
28
IANCU et al.
Table 3
Normative classification of the Culmea Cernei granitoids
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Sample
no.
94
2002
2059
170
92
18
247
2391
82
2010
2416
MI-1
21
84
75
2124
76B
26
172
171
2067
2522
2467
2051
100
199
149
2080
2139
103
147
2126
3
2022
119
2058
87
8
2127
198
Classification
QAP(CIPW)
granodiorite
monzogranite
granodiorite
I H. de la Roche (1984) I
granite
granite
granodiorite
Rittmann (1973)
monzogranite
monzograni te
granodiori te
"
"
"
monzogranite
monzogranite
granodiorite
"
"
"
"
"
'..,
"
"
"
"
"
gran odiori te
"
"
monzogranite
granodiori te
monzograni te
trondj hemi te
»
"
"
"
"
"
"
"
"
"
"
"
"
"
"
granite
granodiori te
monzogranit.e
granodiori te
"
"
"
"
"
granite
granodioritc
"
"
n
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
quartz monzodiorite
grano di or~te
"
monzogranite
granodiorite
monzogranite
granodioritc
n
"
monzograni te
grallodiorite
Lonali te
granodiorite
mOllz ogra ni te
granodiorite
granogabbro
quartz granodiori te with bi, hb
granodiori te
"
"
"
"
lonali te
granod iori te
granodiorite wit.h hb, bi
gran odiorite
"
"
"
"
"
"
quartz monzodioriţe
granodiorite
quartz monzodiorite
gran ite
granodiorite
quar tz Illonzodiorite
incorrect analysis
granodiorite
"
As shown on the diagra ms presented in this paper,
the Cul mea Cc rn ei gra ni toids offer geochemical and
petrochemical argumellls in favour of their generat ion
during subdu ction (group 1, Alllline type, of Hussein
et al , 1982). Geoch emically, th ese granitoid s di ffer
from the granites of group II , in reiat ion to sutures
(formed in a thi cker crus t in collision zones) and from
the granites of group III (anorogenic or within plate
type, gene rated in th e m antie in rela t ioIl to riftogenesis
process ) .
T his genesis is in accordance with both the petrochemical data which make poss ibl e th e cha racterizati on of the Culmea Ce rnei granodioritic calc-alkaline
series as a "medium- K" ser ies and their allochthollous,
synorogenic character.
1 he absence of radiogene dat.ings makes difficult.
t he estimation of the tec t.ogenet.ic events with which
th ese granitoids can be correlatcd in space an d time.
V. IANCU et a.l.
CUL M EA CER TEl GRA NI TOTDS
T able 4 - Characteristic f at ures of t hc Cu lmea Ccrn ei granitoids - compa-rable criteriawith 1 an d S types
Crit e r;a
F i Id
relat; ons hips
M ineralogieal
1 t y p e grani toids
- 8ig complex intrusioI\$
- Widc composit ion li mits:
gabbro-d iorit eş - 15 %
grllnodiori tes - 50 %
granites _. 35 %
- Genet ically a nd spatia lly
rel"led to vo\canics
S type gra.n.it.oids
- Sm ail-si zed intrusions
- Smail composition limits:
gabbro-diorites - 2 %
g r ano diorites - 18 %
granites - 80 %
No conl.emporaueous volcanic rocks
-
- il me nite (common oxide)
- bi, h b prevalence - in mafic
m a gnetite (comm on oxide)
hb prevalence vers us b i
rew musco vi te (felsic v..net ies)
poor in accessory mine r als
colour index := 12.3 (5-27)
(for granodiorit es and monzograrutes
eL Didier el al., 1982)
- Si0 2 - 67.4 (51- 73 %)
-. AhO.3/(Na20+K20+CaO)(mole)::;1.l
- Na 2 0
3.31 %; Na2 0 3.2 % - for
felsic rocks
1.86 % (2.977, ef. Chappel)
- CaO
-K2 0 :=4.13%
( := 2.13 % ace. t.o Chappel aud White)
- E(Fe203+FeO+MgO+MnO+Ti02)
5.66
(2-11 )
- 1""3 3 + /(Fe3 + +Fe 2 + »0.2
-'unifonn variat.ions on the minor elements
diagrams/ differentiat.ion inde x
=
=
Chemic.al
=
Isotopic
Srb
/Sr" ~ <0.706
Culmea Cerne; granitoids
- 8ig complex in t rusions
- Compositions: - QAP diagram '- Fig. 2
- T able 3
monzogran ites - 26 '70
granodiorit es - 66 %
monzodi or i tes - 3 %
tonaJites - 5 %
- No volcanics associaled
- a verage value magn .. tit e - 1.7 CIPW noml
- average val u e ilmenit'e
0.7 CIPW nonn'
- m agnetite > ilmenit.e
- granitoi ds with hb + bi Of bi
- poor in accessory mineral" (Fig. 8)
- colour inde x
11.6 (3-25)
=
vari eties
- occurrence of accessory minerals
- colOl.IT ind e x
4(0-17) (for
leucogra nit.es, ef. Didier et al., 1982)
=
=
- Si0 2 - 72.7 (66- 79 %)
- All03/(Na20+K20+CaO»1.1
- Na20 = 3.35 %
_. CaO
- K20
-$0 2 - 67.55 (58.7 - 76.03 'ro)
- generally ::; 1.1
samples: 2416, 21, 2080, 103, 2022
have values >1.1
- Na20
3.76 % (>3.2 %)
- CaO
2.90 %
= 0.91 %
= 4.42 %
- E(Fe203+FeO+MgO+MnO+Ti02)
= 2.61
(0--6)
Fe~+ /(FeJ+ +Fe2 + )<0.2
- iITcgular variations on t.he minor elements
diagram/differentiat.i on index
-
SI'" /Sr"0<0.706
-
=
=
= 2.56 %
K20
Nb < 10 ppm
E(Fc203+FeO+MgO+MnO+Ti02) = 4.06
FeJ+ /(Fe3++Fe 2+) := 0.42 (>0.2)
uniform val'iations on the minor
elements/ differen tiation index
not given
V. IANCU
30
In this respect, they can be refen d 1,0 th e Lat Proterozoic (" Assyntian")and synchronoLls with th e g ra nitoids associated with the Lainici-Păiu§ Group (Frumosu, Tismana, etc) or to the pre-Ordoviciall Lower
Paleowic (" Caledonian"),
In the former case , a polyp hase l11etamorpltic evolution of the D răgşall anei Lainici- P ăi u§ meg a.5(~qllen ces
took place with a ehange of t he physic al coJldition"
(baric anei therma l) eluring th second v nt . tip intrllsion of the Culmea Cern ei granit.oids being lateorogenic, post-metamorpltic.
In the latte r case, the evolution of the host metamorphitt:s eOllld be cons idercd a:' a polyeycl e o ne, tim
is a reactivat ion of a Proterozoic basement. in the
framework of "island ar ·-type"; in this cas e the allochthonous intrus ion of th e granitoids from th e Culmea C ernei calc- a lka line suite and t hc magma gencration by subduction cOllld be assiglied to Paleozoic
events .
COllclusions
Taking into aecount tlle fi eld observatiolls a lld the
petrological and geoch emical data (Tab, 4) the C1Ilmea Cernei granitoiels can be characteri ze el a.s ~ I1ows:
- mediu m -K, calc-alkalit1e granit.oids (below th e
curve 50 % K on the C K diagram);
- granodiorit.es wit.h monzogra nit "nuclei" pre 10111inat.e, tonali tes and diorites bein g sllbordinated qllantitatively;
- the whol e series plots in tlle field or intermediary
rocks (AbAnOr diagram), which at pressures of 5 kb
would have required t.ell1peratures of m agma.s formation varying between 700 anu 750 aC ;
- the differentiat.ion tendency of th e AFM d iag ral11,
perpendicular on the FiVI side, an d t he conte nt.s of Nb
less than 40-50 ppm, illustrat.e th ex ist.ence of a eo mpressional geot.ectoll ic Illedillm, the rocks falling in t.hc
field of volcanic arc mag m <IS (Nh-Si0 2 qiagrarn);
- t1l!' content.s of min o r elelllents clase 1.0 tho ş~ of
the standard granit.oicls point. 1.0 positive cor reliltions
of Sr with Ca, Ba with Na and K anei of Se. Ca, C r.
Ni, V with Mg and Fe (total),
The fi el el relation hips with t lie ho;;; t. rocks - po lymetamorphic Proterozoic forrnations of t.h c D răg~an
Group - indicate the aliochthqllolls ch ar<t ctcr of lhe
granit.oids, post-metamorphic in relation to the met,amorphic events (M I, M 2 ) ~ut synorogenic wit.h a regional deformational event (D3)'
Genetically, the Culm ' a Cernei g ranitoids L lon g lo
type ''/'' (Na 2 0jK 2 0 diagram), t.h erefar " ign eo lls" 1
type granitoicls cf. Ch app 1 and White (107-1). Considerillg th e fi e ld evidellcr, t.hc Illill era logic al and geochemical data, as well as I he prcse ncc of th e consangu ineous m agmat.ite cnclave.' , the Culmea Cernei gran-
I
et
al,
itoids can be regardeel as M type granitoids (ef. Didier et aL, 1082), that is originating from the mant.\e
or wilh a mixed genesis - mantie + crust.
Th e t ctonic medium In which the Culmea Cernei
granitoids of the medium-K ealc-alkaline series \.vere
generated seems to have beclI control\ed by subduction processes, collsidering thcir appartenance to the
infras Lructure of an island arc type complex (group r,
ef. HlIsse in el al., 1982).
Te mpora lly, the Culmea. Cernci granitoids can be
associatcd with "AssynLi c" (U pper Proterozoic) or
"Caledollian" (Lower Paleozoic) orogenic events,
Referellces
B er cia 1. (197::;) Me l amorfitelc din Jo art~a centrală §i d ..
sud a masivului Godeanu. SI. l ell7l. econ. Insi. Geol,
Geofiz., 1, 12, p, 3-159, Bucllrefjti,
Berza T., Seghedi A. (1975 a) As upra prczentei disten ului În co m plexul amfibolit.ic al seriei de Drăg~an
din bazinul Motrullli. D.S. Ins/, Geol. Geofiz., LX/I,
p. 11- 20, Bucure§t.i ,
• Seghcdi A . ( 1975 b) Complexul filonian presilurian din hazinul Motrullli (Carpaţii Meridionali),
D,S. Insi, G eol. Geofiz., LXI/1, p. 131-149, Bucu rc~ ti .
(1978) St.udiul mineralogic §i petrografic al masivulu i granitoid de Tismana. An, Insi. Geol.Geofiz.,
LIII, p, 5-176, I3u c ur e ~ti,
-
,Seghedi A ., Drăgănescu A. (1988) Unităţile
danllbiene din versantul nordic al Mun~ilor Vâlcan
(Carpatii Meridionali), D.S. Insi. Geol. Geofiz., 7273;'5 (1985; 1986), p. 23-41, Bucures ti.
-
,Drăgăncscu A.(1988) The Ccrna-Jiu fault system (Soulh Carpathians, Romania), a major Tertiary
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72- 73/5 (1985; 1986), p. 43- .5 7, Bucur eşti.
Chap p e l B.W. , White A.J.R. (1974) Two contrasting types of graniles. Pacific Gcol., 8, p, 173-174,
Didier J., Duthou J .L., Lameyre .1 . (1982) Mantie
and crustal granites: genetic clas 'ification of orogenic
granites and the nature of their cnc\aves. lourT!, of
Volcorlology (md G ea/h ermal R esean::h, 14, p,125-132.
Ams terd am,
Husscill A.A., Ali M.M., EI Ramly M.F. (1982) A
proposed new classifica t ion of tlte granites of Egypt.
laur/l. of Volc,malogy J.71d Ceothemwl Rcse(l1'Ch, 14,
p. 187-19 8, Am st erdam,
Iancu V . (1974) COllsid e ra t ii pIiviud geologi a formatiunil or metamorfi e şi a ra cila r grani toide asociate diu
zona Vârful lui Stan - 1'. l)aItinlllui ( Muutii Cernei),
D.S, Insi. C eol, Geofiz .. LX/l, 1',87-108, B ucur e şti,
as li pra rcla~iilor strllcturale ale
de pe eIllsul ;nijlocill al văii Cernei
(ju(LCara"j-S verin),
D,S, Insi,
Ceai.
CfOfiz"
LXII/5, p.39-.5G. I1l1 clII'e§ti.
(1977)
Obs er vaţii
fo rllIaţillllilor
CULMEA CER- NEI GRANITOIDS
-
,Seg hedi A., Măruntiu M., Strusievicz R.
(1 990 ) The structural background of the Brustur Formation in the iuncr d anu bian nappes. D.S. Inst. Ceo/.
Ceofiz., 74/5, p.61-80, Bucure§tl.
-
,Măruntiu M. (1990) Toroni~a zone within the
Relationshi ps Between t.he Geti<: aud the Danubian
Ilealm. D.S. Inst. Ceo/. Ceofiz., 74/1, p.223-237,
Bucure§ti.
, M ărun tiu M.(1994) Reactivated metamorphic
complexes fold and overthrust belts (e.g.
South
Carpathians). in this volume.
Irvine T.N., Baragar W.R.A. (1971) A guide to the
chemical dass ification of t he common vo\canic rocks.
Can. J.Earth Sei., 8, p.523·-S48, Ot.tawa.
Is hi hara S. (1 977) The magnetite series and il meniteseries granitic rocks. Min. Ceol., 27, p.293-30S.
Kleeman A.W. (1965) The origin of granitic magmas.
J.Ceol. Soc. Australia, 12, Canberra.
Kraft M., Schindler R.( 1 961)
Periodisches System
der E lemente. Zusammengestelt von Zentralen :'eologischen InsIi t u t, Berlin.
Lame yre J., Autran A. ( 1980) Les granitoides de
Fra.llce. In: A.A1.ltran and Y.DeTcourt (Editors), Evolutioll geologique de la France . Colloque C7, Geologie
ele la Fran e 26° C. G .!., P aris, p.52-97.
-
, B owdcn P . (1982) Plutonic rock types series:
discrimination of various granitoid series and related
rocks. JOUrT!. of VolcarlOlogy and Ceo/hermal Hesearch, 14, p.169-186, Amsterdam.
Rcceived: M ay 14, 1990
M ay 15} 1990
Presenled. al l!te scientific sess iO T~ of the
Prospec{iu ni S.A.: December 7, 1989.
A ccepted~·
31
La Roche H. de, Leterrier J., GrandcIaude P.,
Marchal M. (:1980) A classification of volcanic
and plutonic rocks using R 1 -R2 diagram and majorelement analyses.
Its relationships with current
nomenclatnre. Chem. Ceol., 29, p.183-210, Amsterdam.
Pearce J .A., Gale G.H.(1977) Identification of oredeposition environment from trace-element. geochemistry. In: Volcanic Processes in. Ore Genesis. InsI.
Min. Metall and Ceol. Soc.London, p.14-24.
Petro W.L., VogeI T.A., Wilband J.T. (1979)
Major element chemistry of plutonic rock suites
from compressional and extensional plate boundaries.
Chem. Ceol., 26, p.217-235, Amsterdam.
Rittmann A. (1973) Stable mineral assemblages of igneous rocks minerals, rocks and inorganic materials.
Springer, Berlin, 262 p.
Savu H. (1970) 'Structura plut.onului granitoid de Su§i~a
§i relaţiile sale cu formati unile au tohtonului Danubian (Carpaţii Meridionali). D.S. InM. Ceol., LVI/S,
p.123-153, Bucure§ti.
-
, Maier O.,Bercia 1., Berza T. (1978) Assyntic
metamorphoseu formations in the Southern Carpathians. Reu. ROtim. Ceol. Ceophys. Ceogr., Ceologie,
22, p.19-29, Bucure~ti.
Streckeisen A.L. (1967) Classification and nomenclature of igneous rocks. Neu e~ Jah,.b. MineT·al. Abh.,
107 (2/3), p.144-240, Stuttgart.
Wright. J .B. (1969) A simple alkalinity ratio and ils application to question of nonorogenic granite genesis.
Ceo/. Mag., 106, p.370-384.
v
IA ",CU ti 01 Cui",..,
c.r-
Gtam_
V . IANCU
GEOLOGICAL MAP - LEFT SIDE OF THE CERNA VALLEY BETWEEN
VARFUL lUI STAN ANO VALEA CĂRBUNELUI
A
p
' --......_~
....'_......._1Dl
....., '"
L
I
E
N
E
G
o
Get ic Realm - Getic Nappe
o
",""zalc Hmalonll'
O
rormGtian~ Sebe, -
IoIQlamorphi c
Ex.ternal Oonu bian Rea lm
r=r:'l
LiW!
~
~
Molozo ic COVIIl" formation.
Q.
PaIeoZOIC
Lotru serilJ5
{~dlyld~!
(Lainici Na ppe)
a Jura.sie - Lawar Cr.!Qcecul
b. Upper C rQtd~ouI
o.vooian
(?) Of Permlon
I?)
formation. · b. Ordoy;elon _ SilurÎa n
Q. LamprophyrQ I
Basie ond intermediary IIIGgmatlt"s . b. Parphyry mlerodlorltlll
c. Al"$oaca diol"iln
.""-
..... in mogmatites in auoelatl a n wllh Culmea Cernel granitoid l
p,- aplltes • 1" - po' phyry mter09'"anodlorltlll; p- pegmatim
6
Cui mfll CQr n i gronitoida IUpp@r Proterol:OIC)
Drli g şan
la
U
Grou p
(PR01EROZOIC I
I"Iicaac.hi.ts an:<l p\agiognell_
Amphlbolitas Qnd amphlbolfc g(1eÎSSel
Lainici -
Pa iuş
Group
(PROTEROZOlCl
! c:::::::' I
Amphlbolilas
LeucogranitlS
Corbonatlc rock a
PiogÎognelue . mlcasehls1s It quorl"lou., t graph ltOll
SAMPLES ANAL.... SED CHEHI CA LLY ANO SPECTRAL L....
~
..
Munzogronlt.
Gror.odÎCIrite
+
TonoU!. - trondhJemite
A
Qua rl"ll',rOOJ. monzodiorlte
CONVENTIONAL
SIONS
Unc® fol""mll y boundnry
Lllho logical boundary
GeoIogieai bounda ry
Fault
/
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Pr-e - Alpill8
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ThruI' pla....
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contoct