Acta Geologica Acade11)iae Scientiarum Hungaricae, Vol. 24 (2-4), pp. 309-318 (1981)

GENESIS OF THE HUNGARIANGRANITOID ROCKS

By

G. BUDA

DEPARTMENT OF MINERALOGY, EÖTVÖS LORÁND UNIV. BUDAPEST, HUNGARY

The granitoid rocks of Hungary classified into two main groups. The closedassociation with regional metamorphic rocks and lower temperature mineral assemblageof granitoids indicate an origin by anatexis and K-metasomatism in South Hungary.The granitoids of Balaton-Velence fault zone are characterised by higher temperaturemineral assemblage with contact-metamorph aureole indicate magmatic origin.

The granitoids have been classified into two main groups according to

mineralogical and petrological characters, tectonic occurrences and age oforigin.

1. Synkinematic anatexite and latekinematic K-metasomatic granitoids(kata-mesozone ).

II. Postkinematic quartz-diorites and granites (epi-zone).

1. The 8ynkinematic Anatexite and Latekinematic K-metasomatic Granites

These rocks are situated in South Hungary (Fig. 1). Large part of thisgranitic and metamorphic belt, except of the Mecsek Mountains, is covered by

thick sediments. The granitoids can be divided into three subgroups accordingto the mineralogical and chemical characters.

a) Basites occur as enclaves in the synkinematic granodiorites, in and

around Mecsek Mountains, Danube-Tisza Interfluve and Békés basin. They

are rich in biotite, amphibole and plagioclase (A.n35)' Microcline is very rare

and occurs as a late crystallized mineral. Q, Or, Ab norms are between 55-7°%(Table 1). The rocks are rich in Mg and Ca (Fig. 2).

b) Synkinematic porphyroblastic granodiorite occurs in and aroundMecsek Mountains, Danube-Tisza Interfluve and Békés basin. The anorthite

content of plagioclase is high in the granodiorite of Mecsek Mts. The relatively

disordered structure and predominant complex-twins of plagioclases indicatea higher temperature of formation. The anorthite content decreases from MecsekMts. towards the area surrounding of Mecsek Mountains and Danube-TiszaInterfluve. The decrease of anorthite content is followed by a higher degree

II Acto Geologico Acodemiae Scientiarum Hungaricae 24, 1981

~li

<;1~

of~

CI.)....o

Table 1

South Hungarian granitoids and associated rocksBasic-Enclaves or Resistites(Q + Ab + Or = 55-70%)

:..2....

~.~~

rits.~~a~~~.~

Normatíve ratios (CIPW) .

/

Catíon ratíos (NOCKOLDS)

I I

No.-- Ab/An. Sampl.

Q I Ab I ori An. I Ab I Or T~~al I ~l [ Mg I T~~all Mg I Ca [ KINa I Ca I + total

~1~~I~~L.~'~.:1~~:~J~7~1 23.2149.41~~1~1~1~~1~1~~1~1~~1~

O.cnrrenec

Mecsek Mountains

Surroundings ofMecsek Mts.

18.0 I 39.2142.811~1.91~4.11 44.0II 19.91~1 24.8 28.71~~' 36.4 ~~I 36.4j~~II~I_~

~~i~0.41~1~7.81~.4 ~~! 20.01~~ 20.7 34.9 36.0 29.1~~~9.5 ~~I~~_~33.5

1

40.5 26.0

1

20.3 47.8 31.9

1

23.8

1

58.5 17.7 39.2 28.6 32.2 29.1 45.8 25.1

/

2.9 8

~~~1~8Ü3~~~~n7~~~~038~~~~

t!j

§~

~

Danube-Tisza Inter-fluve

'"."" Békés basin....'"00.... Average

Synkinematic anatexite (Granodiorites)(Q + Ab + Or = 70-80%)",' "4

1

-,-

-,-

o-,-,

o-,-

4-,-

4

Mecsek Mountains 34.6 31.7 33.7113.41.

Surroundings ofMecsek Mts. 19.3 42.0 38.7 10.2

32.51 39.4- --o

Pécs-7 28.1 10.2-

-1---'Danube- Tisza Inter-

fluve 46.2I 28. -Békés basin 38.1

39.21 22.7 9.9Avere I-;u 35.7 30.2 10.0

, 19.3[ 36.3 37.5 26.211 17.41

.116.8 66.9 16.3 36.7 35.5 27.8 38.5 45.7 15.8 4.5 16----- 8.21--:;;-

-19.8 60.9 19.3

38.4 22.4 33.9 50.9---- -----

-1 27.663.3 9.1 58.7 19.0 22.3 43.4 42.4 14.2 8.2 6---- ---

I 17.769.4 12.9 41.7 30.5 27.8 30.8 54.6 14.6 9.5 II

'I-;;U- 6U -;:5.4125r 25.3/-;7.7 46.9151 6.8 44

........*

Latekinematic K-metasomatic granites(Q + Ab + Or = 80-100%)

1>....it

r

f-l>.2tffris.§~.;;:~.~.~...~

~~tnSo";j

~..,o13~8

w........

Mecsek MountainsI 37.41 28.7 3.9 50.2 9.0 86.8 4.2

I 42.2 15.7 18.3 43.3 1_8.81Surroundings of

Mecsek Mts. 29.1 34.2 36.7 2.4 47.4 50.2 8.9 83.4 7.7 41.9 31.1 27.0 43.4 49.5 7.1 21.4 10--- -

9.61 80.31 10.1

- - -- - -- - -- --Pécs-7 35.3 31.2 33.5 6.0 45.6 48.4 33.8 35.9 30.3 45.3 45.1 9.6 8.2 2------Danube-Tisza Inter-

fluve 38.7 30.5 30.8 5.4 46.3 48.3 8.9 87.6 3.5 47.2 18.1 34.7 45.8 46.5 7.7 16.7 10- - ---- -- - - -- - - - -- -- - - -Békésbasin 36.5 32.9 30.6 7.3 48.0 44.7 11.7 82.0 6.3 41.0 23.0 36.0 41.8 47.6 10.6 7.2 7

35.4 31.5 33.11 45.9

- -- - -- - -- - - - - - --Average 48.4 9.6 84.0 6.4 41.2 26.0 32.8 44.9 46.4 8.7 12.4 37

312 BUDA, GY.

?~2f'f'fs,okm -.~ / ~-'

\

t~~l

J"',,~ f~ "--;71\, -' ~ ~*"" €. <o€.'-\ /

""'.

, ~~~'~ '"

i~~"'" - c) .;..,0 ,#'. ,

.'if' ,p r ...

) #~ca ~~ ""O r'\

~ ~~""D~ ::: m ,,-1,~~ {

..>~O' /" < ';."'# . r\,05\ \~, ;;Itsat;ór mA>\..~ X

\ G:;s ,.4~QtonfeoYV'5 ~~I(eéskemét

ri

'\::--- ~ ""sok ~~SOltvadkert..~l'~ -",C"~ é- ." ", ' o"~""oV .;" /",,$.(>.,,"OX)1;..~~<; .>" //,1!f "~/ "O/'" ~ ,...'t':\.' x'X,,,~'1 . eá<'"""'"~

"". x ;x-~-~", '" ~M6rOgy A r r.-:"l

~..,/ r--~ . '" ~ ,'0-. J/!' nJ~ ~~W

- '''''' 13

Fig. 1. Map showing the granitoid occurrences of Hungary. 1. Granite and granodiorite;2. quartzdiorite; 3. anatexitic granodiorite and granite

of ordering and decreasing amount of complex-twins indicating a lower temper-ature of formation.

Porphyroblastic potassium feldspar is common constituent with more

or less ordered structure (maximum or nearly maximum triclinicity). They arerich in inclusions of biotite and relict plagioclase and sometimes show cross-

hatched twins. The crystallization temperature of microcline and plagioclasewas ahout 550-590 oC (at 5 kb) counted according to WHITNEY and STORMER'S

method (1977). The K-feldspars occur in the groundmass too. Their triclinicities

differ from the porphyroblasts. In Mecsek Mts. the triclinicity is medium ingroundmass and maximum in porphyroblast. In Danube-Tisza interfluve

microcline has higher degree of triclinicity in groundmass and porphyroblasthas the same degree of ordering than in Mecsek Mts. Around Mecsek Mountains

the double triclinicities are rare (average LJ = 0.65). Perthite of K-feldspar iscoarser in granodiorite of Mecsek Mountains than in the Danube-Tisza Inter-fluve.

Sum of Q, Or, Ab norms is between 70-80% (Table 1). The rocks are

characterized by high alkali content (Fig. 2).c) Latekinematic granites occur as dykes and small batholiths in the

synkinematic granodiorite, they are pinkish, fine-grained, equigranular andrarely cont ain biotite. Perthitic microcline of high triclinicity (LJ = 0.90) iscommon. The plagioclase has an ordered structure and its higher Ab content

indicates a low temperature of formation (480 oc). The cross-hatched micro-cline pseudomorphs after plagioclase suggests K-metasomatic origin.

Acla Geologica Academiae Scientiarum Hungaricae 24. 1981

--

GENESIS OF GRANITOID ROCKS 313

Fe". Fe-(K)

+ 102(t 3/Al.xSEJ6.7

No+KNa

MgCa

Fig. 2. PIots of K-Na-Ca and (Fe2+ + Fe3+)-(Na + K)-Mg. 1. Mecsek Mountains2. surroundingsof MecsekMts.; 3. Pécs-7(borehole);4. Danube-Tisza Interfluve; 5. Békés

basin; 6. average(South Hungary); 7. average(Balaton-Velence fault-zone)

Sum oJ Q, Or, Ab norms is between 80-100% (Table 1). The rocks arerich in alkalies due to the aIkali metasomatism (Fig. 2).

The synkinematic granodiorites of Mecsek Mountains are rich in Annorms (Table 1), whereas gran odiorit es of Danube-Tisza Interfluve and Békésbasin (Table 1) are rich in Q norms indi cating that the form er crystallizedunder higher pressure then latter.

The higher An content of the latekinematic granites of Mecsek Mts.and high Q content of granites of Danube-Tisza Interfluve indicate a relative

higher pressure and temperature conditions in the Mecsek Mts. compare withthe Danube-Tisza Interfluve (Table 1).

Acta Geologica Academiae Scientiarum Hungaricae 24. 1981

314 BUDA, GY.

Q

O~VELENCEMTS(27) POSTKINE-AMATIC. ----

aSOUTH HUNGARIAN(37) LATEKINEMATICVARISCAN (HALL 1971) (98) .

CALEDONIAN (HALL 1971)(41)

ALPlNE (HALL 1971)(5)

vAb

Fig. 3. Average composition of granites of different ages in the system Q-Or-Ab-~O.Points indicate isobaric minima at water pressurebetween0.5 and 10 Kbar. (after: TUTTLE

and BOWEN. 1958 and LUTH et al.. 1964). The figures in brackets indicate the numberof samples

The average Q. Ab, Or norms of the granites are strikingly similar tothe West European Variscan granites (HALL, 1971, 1972, Fig. 3), therebysuggesting similar age of origin. This is also supported by the isotopic agedetermination (KovÁcs etc., 1968).

Petrogenesis

An eugeosyncline had been filled up with sediments and basic volcaniteswhich were regionally metamorphosed. The deepest part of the geosynclinesubjected to anatexis along the belt of Mórágy-Miske-Soltvadkert-Kecske-

Acla Geologica Academiae Scientiarum Hungaricae 24, 1981

GENESIS OF GRANITOID ROCKS 315

An

0 1

A.2

Ab

Fig.4.An-Ah-Or proportions of Hungarian granitoid rocks. 1. Average composition ofSouth Hungarian granitoids; 2. average com pos iti on of granitoids occurring along the Velence-

Balaton fault zone

mét. The temperature and pressure conditions prevailed during the anatexite

formation correspond with the amphibolite facies. This synkinematic anatexistook place in a closed system with the presence of volatiles, at elevated temper-

ature and pressure caused by the subsidence of sediments.Further subsidence of the rigid synkinematic rocks (anatexite granites )

caused K mobilization in the groundmass which migrated to the newly formed

fissures. The intensity of mobilization was greatest in the deepest parts of thegeosyncline. This K-migration transformed the granite into granodiorite in the

Mecsek Mts. The transformation of granite into granodiorite in the Danube-

Tisza interfluve was incomplete due to lower intensity of K-migration.

Acta Geologica Academiae Scientiarum Hungaricae 24, 1981

.

:..~~

Table 2

f.

Postkinematic intrusives of Balaton- Velence fault zoneQ-diorites

:..~s~.

r~

g.§~~

Q

~.g Granodiorites

~.....'"00.....

Granites

Velence MountainsII 37.21 31.31 31.511 8.71 45.21 46.11112.41 82.21 5.41149.0118.91 32.11144.41 46.31 9.311 7.41

* 1. Dinnyés; 2. Gelse

ti.)....cn

§.r-4")~

27

Norroative ratio8 (CIPW) Cation ratio8 (NOCKOLDS) No.Occurrence

I Ab I I I I I

Ab/An 8aropl.

Q Or An Ab OrTotal I Total I Mg Total I

MgI

Ca K Na Ca + totalFc AIk. Fc

Boreholes (1. 2.)*25.61 45.51 28.9 35.61 39.41 25.0 29.11 50.51 20.4 34.11 23.8 [ 42.1 21.91 36.51 41.6 Lll

4

Velence Mountains26.8! 42.71 30.51 16.8! 47.81 35.4 34.21 46.4119.41 51.41 28.0 I 20.6 I 31.61 45.11 23.3 3.7!

2

Buzsák (boreholes)I 35.61 36.31 28.1 15.31 47.81 36.9 18.21 62.2119.6 35.21 37.9/ 26.9 34.51 47.2118.3 3.2[

2

Velence MountainsI 37.41 32.61 30.0 11.61 42.51 45.9 18.51 73.2/

8.348.21 23.3/ 28.5 44.11 43.1112.8 3.21

6

GENESIS OF GRANITOlD ROCKS 317

The mobilization of K, Na, Si etc. produced the late-kinematic K-meta-somatic microgranites and aplites which filled up the fis sur es of the granodio-ritic body.

II. Postkinematic Quartz-diorites and Granites

Two igneous rock types occur along the Balaton-Velence fault-zone.a) Quartz-diorite (tonalite) has been reached in the boreholes at Dinnyés,

Gelse and also found as enclaves in the granite of the Velence Mts. (Fig. 1).Anorthite rich plagioclase (An50) is the predominant constituent with zonedtexture. Microperthitic orthoclase is rare. Quartz sometimes shows wavyextinction. Biotite is mostly chloritized. Hornblende is rather common andzircon, titanite, apatite and rutile occur as accessory minerals.

Chemical differences have been observed between the quartz-dioritefrom boreholes (Dinnyés, Gelse) and the enclaves of the Velence Mts. Theenclaves are rich in Or and poor in An norms indicating K -metasomatismcaused by the huge mass ofK-rich granitoid pluton (Table 2).

b) Granite-granodiorite intrusions have been studied in Velence Mts.,Ságvár and Buzsák areas (Fig. 1). The average anorthite content ofplagioclasesare similar (An30)' Complex-twins are prevailing and Al/Si ordering is mediumdegree.

The K-feldspar has disordered structure. The temperature of formationwas about 630-650 oC counted according to 1. C. STROMER'S(1975) method.

The average chemical composition of these rocks are granitic, but minordeviation has been observed. The granodiorite occurs in the borehole of Buzsákand in the margin of the granitic pluton of Velence Mts. (Table 2).

Granites ofthe Velence Mts. are rich in Q and poor in An norms (Table 2)indicating lower pressure conditions of formation compared with the SouthHungarian latekinematic granitoids (Fig. 3 and Fig. 4). Their age, determinedby isotopic (Sr/Rb) method, is Variscan (310-330 million years). They arechemically very similar to the West-European Variscan granites (Fig. 3).

There are no direct evidences to establish the relationship existing be-tween quartz-diorites and granites, however, enclaves in the Velence granitessuggest that the earlier intrusion was quartz-diorite and it was followed bygranodiorite-granite.

Acta Geologica Academiae Scientiarum Hungarica. 24, 1981

318 BUDA, GY.

REFERENCES

1.BUDA,Gy.:Classification ofthe Hungarian granitoid rocks on the basis of feldspar investiga-tion. Carpathian-Balkan Geological Association, Tectonics (sec. IlL), pp. 67-74,1975.

2. HALL, A.: The relationship between geothermal gradient and the composition of graniticmagmas in orogenic belts. Contr. Min. and Petrol., 32, 186-192, 1971.

3. HALL, A.: Regional Geochemical Variation in the Caledonian and Variscan Cranites of Wes-tern Europe. Int. Geol. Congr. Sec. 2., pp. 171-180, 1972.

4. KLEEMAN, A. W.: The origin of granitic magmas. J. Geol. Soc. Aust., 12, 35-52, 1965.5. KovÁcs, A.-K. BALOGH-Z. SÁMSONI:Contributions to the dating of the Mecsek granites

by RbjSr method. Bulletin of the Hung. Geol. Soc. V., XCVIII, 205-212, 1968.6. LUTH, W. C.-R. H. JAHNS-O. F. TUTTLE: The granite system at pressures of 4 to 10 kilobars.

J. Geophys. Res., 69, 759-773, 1964.7. STROMER,1. C.: A practical two-feldspar geothermometer. Am. Min., 60, 667-674, 1975.8. TUTTLE, O. F.-N. L. BowEN: Originof granitein the light of experimental studies in the sys-

tem NaAISiaOs-KAlSiaOs-SiOa-HaO. Geol. Soc. Am. Mem., 74,1-153, 1958.9. WHITNEY, 1. A.-I. C. STROMER:The distribution of NaAlSiaOs between coexisting microcline

and plagioclase and its effect on geothermometric calculation. Am. Min., 62, 687 -691,1977.

l{ rEHE3I1CY BEHrEPCl{I1X rPAHI1TOI1,QOB

~b. EY~A

Pe310Me

rpaHHTOH,lJ;bI BeHrpHH OTHOC5lT1( ,lJ;BYMrJIaBHbIM rpynnaM. npHypOqeHHOCTb rpaHHTOH-,lJ;OB1( perHOHaJIbHO MeTaMOp.pH30BaHHbIM nOpO,lJ;aM H HX HH3I(OTeMnepaTypHbIH MHHepaJIbHbIHnapareHe3 Ha TeppHTopHH IO)f(HOH BeHrpHH CBH,lJ;eTeJIbCTBYIOT06 06pa30BaHHH B pe3YJIbTaTeaHaTel(THqeCI(HX H l(aJIHeBOMeTaCOMaTHqeCI(HX npOl\eCcoB. rpaHHTOH)J;bI 30HbI pa3JIOMOB BaJJa-TOH-BeJIeHl\e xapal(TepH3YIOTC5l MHHepaJIbHbIM napareHe30M nOBbIIIIeHHoH TeMnepaTypbI 06-pa30BaHH5l c 1(0HTaKToBo-MeTaMop.pHqeCI(HM OpeOJIOM, qTO CBH,lJ;eTeJIbCTByeT o MarMaTHqeCI(OMnpOHCXO)f(,lJ;eHHH nopo,lJ;.

Acla Geologica Academiae Scientiarum Hungaricae 24, 1981