Protholithic Age and Geochemistry of Magmatic Rocks from the Serbo-Macedonian Massif (South Serbia, Southwest Bulgaria and Macedonia) M
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PROTHOLITHIC AGE AND GEOCHEMISTRY OF MAGMATIC ROCKS FROM THE SERBO-MACEDONIAN MASSIF (SOUTH SERBIA, SOUTHWEST BULGARIA AND MACEDONIA) M. Antić¹, I. Peytcheva², A. von Quadt³, A. Kounov¹, B. Trivić⁴, T. Serafimovski⁵, G. Tasev⁵ and I. Gerdjikov⁶ ¹Geologisch-Paläontologisches Institut, Universität Basel, 4056 Basel, Switzerland, ²Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, ³Institute of Geochemistry and Petrology, ETH-Zürich, 8092 Zürich, Switzerland, ⁴Faculty of Mining and Geology, University of Belgrade, 11000 Belgrade, Serbia, ⁵Faculty of Natural and Technical Sciences, University "Goce Delčev" - Štip, 2000 Štip, Republic of Macedonia, ⁶Faculty of Geology and Geography, St. Kl. Ohridski University of Sofia, 1504 Sofia, Bulgaria Serbo-Macedonian massive (SMM) is a N-S stretched zone, situated Results of the fission-track analysis on zircon and apatite grains from the magmatic rocks of the LA-ICP-MS U-Pb analysis of igneous rocks from the SMM and surrounding units ( 22°E Lower complex, Vlasina unit, Crnook dome and Late magmatic bodies is presented in figure 2.1. in the central part of the Balkan Peninsula. It outcrops from the yielded magmatic ages (red) grouped in four clusters, and various inherited ages Era Period Epoch Modelling of the thermal evolution of the samples, using the HeFTy software, yielded three dif- Pannonian basin in the north, to the Aegean sea in the south. SMM (orange) as old as Mesoarchean. The oldest, Cadomian event is recorded in both Leskovac ferent major thermal histories. Please note that the annealing model is not sufficiently sensitive parts of the SMM, Veles series as well as Crnook dome. Ordovician igneous activ- ( 43°N .! 43°N is bounded by the west-vergent Eastern Vardar zone (remnant of below 60°C. Figure 2.2 depicts the effects of late Eocene cooling following the 37-31 Ma pulse of 43°N43°N ity continued only in the Lower complex and the Veles unit. There are two occur- SM331 Lece 30 SM207-1 ( Mesozoic Tethys) in the west, and is thrusted over the east-vergent magmatic activity. This event affected most of the observed samples from the Vlasina unit. rences of late Permo-Triassic magmatism in western Lower complex, and in 33±0.5 33±2 SM216-1 Oligocene ( Geticum units in the east. The SMM is divided into the Lower com- Samples from the Crnook dome revealed the fast cooling in early Eocene related to tectonic Crnook dome. Late Surdulica granite was intruded in late Eocene, followed by the Južna Morava 35±1.5 50°N C 30°E unroofing of the Crnook-Osogovo-Lisets core complex (Kounov, 2002), followed by the slow volcanic and hydrothermal activity. 36±1 36±3 ( a plex and the Vlasina unit (upper unit) (Dimitrijević, 1959), both rep- Cenozoic r Paleogene 18°E pa th cooling (Figure 2.3). Samples from the Vlajna and Kukavica granite of the Lower complex show ia n resenting volcano-sedimentary complexes, metamorphosed to am- 40 ( s relatively fast cooling in the middle late Cretaceous (Figure 2.4). In the late Eocene reheating ( Pannonian phibolite and green schist facies respectively. Contact between Eocene Tran event is observed probably related to the magmatic during that period. Era Period basin .! 0.010 50 A change Ð these two units was interpreted as a brittle Vrvi Kobila westward 150 in scale B Lower complex ages 0 0.009 160 Dark gray = concordance 95-105% 160±4 thrust, outcropping southeast of Leskovac, Serbia (Vukanović et al. 0.60 Light gray = concordance <95% & >105% Vlajna AFT age [Ma] 0.008 40 ( Miocene basin Age group: 200-950 Ma 560±5 Moesia Black Model: 34.9 170 A 0.55 0.007 173±6 Sea 1965). Apart from scarcely documented ‘Pb-Pb zircon ages’ for Measured: 35.1±5.8 F S VELES D E 20 i R r n GOF: 0.96 180 e B 0.006 30 BALKAN 0.50 q y ( a O t r u 452±9 i i l i 83±9 94±5 e d - Vlajna and Bujanovac plutons (450Ma and 347Ma respectively; Ð M Jurassic # b * n e 0.005 s 190 a A Srednogorie 0.45 MTL [µm] c b 192±7 C y o E Model: 14.78±0.67 r ( D Dimitrijević, 1997), paleontological findings represent the only P 0.004 20 567±28 *# O 40 200 N 0.40 Measured: 14.51±1.05 I ] # C * 488±8 A RHODOPE Vardar Pelagonia N ° GOF: 0.98 0.003 ( [ y *# Vlasinsko j. ( e chronological data related to the age of these metamorphic do- 210 Mesozoic r 0.35 H c u n 0.002 10 t ( ( ( 74±6 e 40°N e a l u 73±5 83±6 l r 220 q e e 516±9 ( 60 0.30 mains. Sericite-chlorite schists northeast of Vlasina lake were dated e 0.001 n p i r 225±7 VLASINA F 40°N d m e e STRUMA ( Aegean 230 s T 0.25 0.000 0 2 3 4 5 6 7 8 9 0 0 0 0 0 0 0 0 ( to be of Ripheo-Cambrian age by sphaeromorph acritarchs ( 39±4 79±4 ( Sea 0 0 0 0 0 0 0 0 240 Triassic es 80 0.20 Age [Ma] rid (Rakićević et al. 1969). Palinomorphs found in ‘flysch-like’ sedi- au 250 BASEMENT Božica D T Apatite PAZ 0.15 253±13 C Ð *# Surdulica ments of the northeasternmost thrust of Vlasina unit yielded Devo- 260 *# ( 0.10 ( Vranje ( 100 ( ( nian to lowest Carboniferous age (Pantić, 1960 and 1963). The con- 270 *# 0.05 .! 546±7 ( ( Mediterranean Ð 33±0.5 #* 0.00 280 281±7 18°E Sea 30°E troversial Veles series (Vukanović et al. 1977) with differing lithol- 282±8 0 2 4 6 8 10 12 14 16 18 20 ( 36±1 35±3Ð 120 Length [µm] 281±7 ogy and deformational style (Dimitrijević, 1997) is situated in the 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 290 Permian # Time [Ma] * 299±9 300 ( Bujanovac # southwest of the research area, between the Lower complex and Figure 2.2. Late Eocene magmatic cooling. Left: Time-Temperature path; black line represents the best fit model. Right: Track length histogram; green line represents the best fit model. COMPLEX LOWER 42±4 41±4 310 .! 0 313±10 Ð the Eastern Vardar unit. In the eastern part of the SMM, Crnook Miocene basin ( 36±3 23°E 20 320 253±13 F AFT age [Ma] 324±7 dome (part of Crnook-Osogovo-Lisets dome that represents Struma 40 0.35 Model: 39.3 330 60 Measured: 41.6±6.8 *# Ð *# basement) is exhumed during the Cenozoic extension along low GOF: 0.51 340 E 33±2 80 0.30 Apatite PAZ 350 ( Ð angle detachments (Kounov, 2002). Our research is poised to reveal MTL [µm] Carboniferous 100 Model: 14.14±1.05 ] C 360 SM199-1 Bujanovac Granite SM199-1 Bujanovac ° 0.25 Measured: 13.95±1.18 MAGMATICS CENOZOIC [ 120 the major magmatic events as well as the deformational history of ( *# e GOF: 0.79 r y u 370 t 140 515±4 c *# a n r 443±6 e the area. Apart from the field observations, we are relying on the e 0.20 u 378±5 Legend p Ð 160 q 380 Kjustendil granite SM216-1 Surdulica e m r e F 78±6 T 180 .! low temperature geochronology methods (apatite and zircon fission 390 Ð ( Ð 0.15 ( ( ( 200 Detachments track and Ar/Ar dating) together with U-Pb zircon dating and geo- 400 220 Devonian chemical analyses. 0.10 410 amphibolite SM173-1 Vinica ( Thrusts 240 Zircon 420 Ð 260 422±6 424±14 Osogovo FT age 0.05 280 430 gneiss SM315 Preševo Paleozoic SM250-1 Golemo Selo amphibolite SM250-1 Golemo Uncertain faults Ð 110 300 440 0.00 Silurian 443±6 Struma 0 2 4 6 8 10 12 14 16 18 20 445±12 ( 60 58 56 54 52 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Length [µm] Strike-slip faults 450 pl. gneiss SM184-1 Maleševska 452±9 Ð Time [Ma] rhyolite SM331 Stajovce 100 aplite SM173-3 Vinica Ð Ð Figure 2.3. Early Eocene extension in the area of Crnook-Osogovo-Lisets dome. Left: Time-Temperature path; black line represents the best fit model. Right: Track length histogram; green line 457±11 Lower complex 460 represents the best fit model. Ð 464±6 465±6 0 Unresolved kinematics 470 469±5 469±6 90 Cretaceous granite SM01 Kukavica ( 20 AFT age [Ma] 480 .! Ð basin 40 0.45 Model: 69.4 Ordovician Ð 487±6 488±8 *# 80 60 Measured: 72.8±10.9 490 490±4 489±5 Granitic samples GOF: 0.53 493±10 Apatite 0.40 SM195-1 Štip granite 496±14 Kratovo-zletovo 80 498±32 granite SM272-1 Božica 500 ] 100 PAZ MTL [µm] gneiss Pčinjski SM202-1 Prohor *# a 70 SampledSkopje gneisses 0.35 Model: 13.39±1.01 510 M 120 512±8 513±15 [ 540±7 ] Measured: 13.10±0.98 42°N 516±17 516±12 516±4 516±9 42°N C ° [ .! e GOF: 0.87 140 0.30 520 y 42°N e *# g r *# c Maffic samples 525±6 granite SM140-1 Delčevo 42°N u a 60 n t 160 e a u SM250-2 Golemo Selo gneiss SM352 Lisina gabbro T r 530 ( q e 0.25 F Cambrian e p 180 r Vlasina F m 540±7 *# Sampled Cenozoic magmatics e 540 50 T 200 544±27 0.20 546±7 SM02 Vlajna granite 548±6 220 550 549±15 549±16 422±6 240 0.15 560±5 Zircon U-Pb age Delčevo 40 560 560±18 560±5 260 Zircon 567±28 *# 0.10 570 Young 280 573±5 *# 30 FT age Zircon fission track age magmatics 300 0.05 580 79±4 320 586±11 Struma basement 590 590±8 0.00 594±12 469±6 ( 340 0 2 4 6 8 10 12 14 16 18 20 ( 20 Length [µm] 600 603±18 42±4 Apatite fission track age 200 400 600 800 1000 1200 1400 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 605±9 Time [Ma] Ediacaran 610 611±14 Altitude [m] Figure 2.4.