GEOLOGICA BALCANICA, 33. 3-4, Sofia, Decemb. 2003, p. 49-56 Neotectonic and seismotectonic features of the Pelagonian, Kicevo and Porec depressions and the surrounding block structures 1 2 1 Zlatko Iliovski , Vojo MircovskP, Gose Petrov , Orce SpasovskP, Stojance Nikolov 1/nstitute for Civil Engineering "Macedonia" Skopje, Republic of Macedonia 1Faculty of Mining and Geology Stip, Republic of Macedonia (submitted 7. 08. 2001; accepted for publication: II. 06. 2002; last version received: D ecember 2002) 311 . 11JIU08CKU, B. Mup<t08CKU, r n empoe, 0 . Cnacoec­ Abstract. The paper presents the lithostratigraphic, KU, Cm. HuKOJIOB. H eomeKmOIIU'IeCKO.fl u ceilcMomeK­ neotectonic and seismotectonic characteristics of the moHu'lecKaJI xapaKmepucmuKa lleAa2oHuilcKou, Ku­ Pelagonian, Porec and Kicevo depressions and the sur­ ~.JeecKou u llope'lKOU oenpeccuii u OKPJ:>ICOIOU{UX 6JIO · rounding horsts. K08b/X cmpyKmyp. 8 pa6oTe npHae.aeHa xapaKTepHCTHKa The area under consideration belongs to two geotec­ HeCKOJlbKHX HeOTeKTOHH'IeCKHX .nenpeCCHH (Denaro· tonic regions - the Pelagonian massif and the Western HHHCKOH, KH'IeBCKOH H nope4KOH), a TaK)f(e - OKpy)f(a· Macedonian zone which have had a complex multiphase IOlllHX 6JJOKOBbiX CTPYKTYP· geotectonic evolution. J.1ccne.nosaHHblH paHOH npHHa)lJJe)f(JH K JlBYM r eoTeK· During the Neotectonic stage, owing to the intense tec­ TOHH'IeCKHM perHOHaM - K OenarOHHHCKOMy MaCCHBY H tonic development, morphostructures of uplift (block­ K 3ana.nHOH MaKe.noHCKOH JOHe. 06a perHOHa npownH horsts) and subsidence (depressions-grabens) were CJlO)f(HOe nOJJH<pa30BOe reoTeKTOHH'IeCKOe pa3BHTHe. formed along reactivated older and newly-developed 8o apeMH HeoTeKTOHH'IeCKoro nepHo.na a peJyJJbTaTe neotectonic fault structures. The neotectonic fault struc­ HHTeHCHBHblX TeKTOHH'IeCKHX .UBH)f(eHHH no peaKTHBH · tures are of various degree of seismic activity. The analy­ poBaHHblM H HOB006pa30BaHHblM HeOTeKTOHH'IeCKHM sis of data from earthquakes makes possible to distin­ pa3JlOMaM OcpOpMHJlHCb MOpcpOCTpyKTypbl B03.Ub!MaHH.II guish two seismic zones - Kicevo and 8itola, - in which (6JJOKH - ropCTbl) H CTpyKTypbl npoce.naHHH (.nenpeCCHH earthquakes with a magnitude of up to 5.5 could be an­ - rpa6eHbl). HeoTeKTOHH'IecKwe pa3JJOMbl pa3JJH'Ia!OTCH ticipated. no cTeneHH cei-icMH'IeCKOH aKTHBHOCTH. Ha ocHoBaHHH aHaJlH3a .naHHblX no JeMJJeTpHCeHHHM Bbl.IIBJleHbl .UBe Ce· HCMH'IeCKHe JOHbr - JOHa Ky'leBo H JOHa EwTon .R. 8 CBH · 3H C HHMH MO)f(HO O)f(H,UaTb JeMneTpHCeHH.II C MarHHTy· JlOM .UO 5.5 CTeneHH. Iliovski, Z., Mircovski, V., Petrov, G., Spasovski, 0., Nikolov, S. 2003. Neotectonic and seismotectonic features of the Pelagonian, Kicevo and Porec depressions and the surrounding block structures. - Geologica Bale., 33, 3-4; 49-56. Key words: seismicity; neotectonic structure. Pre-Neogene tectonic evolution part of the Dinarides. The horst is separated from adjacent tectonic units from all sides by The area of the Pelagonian, Kicevo and Porec deep faults of NNW to submeridional strike. depressions and surrounding horsts occupies In 'the east it borders the Vardar zone and in parts of the Pelagonian massif and the West­ the west the Western-Macedonian zone. A ern-Macedonian zone (Fig. 1). study of the evolution of the Pelagonian massif The Pelagonian massif is a relict of the Pre­ during the Phanerozoic gives grounds to as­ cambrian, Pre-Baikalian earth's crust in this sume that it was, and still is, a stable block 7 Geologica Balcani ca, 3-4/2003 49 N '{ \J G ~ ,· ,.,. ' . .\ ' '-·.. -· I <( Stip vz 0 I z \ ~ \ -·--~- .., .~-~ <( 0 20km G I I G Fig. I. Tectonic setting of the territory of Macedonia (a~ter Arsovski, 1997). CKZ- Cukali-Krasta zone, ZMZ- Western-Macedoman zone, PM- Pelagoman masstf, VZ - Vardar zone, SMM - Serbo-Macedonian massif, KZ - Kraistide zone (microcontinent) in which vertical oscillation Neotectonic evolution movements have played a major role. During the Alpine tectonogenesis the Pelagonian mas· The territory of the Republic of Macedonia is sif was an internal massif with tendency of per­ part of the Mediterranean orogenic area where manent uplift. basinal conditions terminated by the end of the The Western-Macedonian zone represents Paleogene and the beginning of Neogene. This an inner massif situated in the northeastern was followed by continental development. part of the Dinaride-Helenides. In the west it During the first phase or the Lower Miocene borders the Mirdita zone (in the territory of intense peneplenization and nivelation of the Albania). It borders also partially the Cukali structures of the Pyrenean to Savian orogenic zone (in the area of Debar). Its eastern border, phase took place. towards the Pelagonian massif, represents a During the Middle Miocene a period of ex­ regional fault zone. tension and evolution of neotectonic move­ The initial stage of the development of the ments took place, as well. Intense vertical zone is associated with the break up of the pri­ movements resulted in the development of nu­ mary Grenvillian crust during Riphean - merous morphostructures of uplift (horsts) Cambrian times. During the Hercynian orog­ and subsidence (grabens). The process of dif­ eny intrusion of granite magma resulted in the ferentiation displacements between depres­ development of large batholite bodies such as sions and horst massifs was intensified with the Pelister and Krusevo granitoids. time which resulted in the activation of earlier 50 I \ ~ ,; ~ '.- .. , \.. '· ... 0 s \ \) G ~ \ "( \ c.. ... (' ' "' \ ,; \ 4:: , .. I / "' 7 z 4:: (]) _J \ 4:: ' c ~ ~ 0Horsts D Depressions 0 50 km EiJ Volcanic areas Fig. 2. Neotectonic setting o.f the territory of Macedonia (after Arsovski, 1997). Horst morphostructures: I. Sar Planina, 2. Korab, 3. Bistra, 4. Stogovo, 5. Jablanica, 6. Galicica, 7. Ilin, 8. Pelister, 9. Semnik, I 0. Ljuben, 11. Pesjak, 12. Suvogor, 13. Zed en, 14. Jakupica, 15. Babuna, 16. Selec, 17. Srpsko-Crnogorski, 18. Raduca, 19. Kadina, 20. Bregalnica, 21. Klepa, 22. Mariovo, 23. Plaus, 24. Kozuf, 25. Furka, 26. Kozjak, 27. Osogovo, 28. Ruen, 29. Golak, 30. Males, 31. Plackovica, 32. Belasica. Subsidence morphostructures (depressions): I. Polog, II. Ohrid, III. Debar, II-III, Drim graben, IV. Prespa, V. l(jcevo, VI Belciska, VII. Pelagonian, VIII. Porec, IX. Skopje, X. Kumanovo, XI. Ovce Pole, XII. Tikves, XIII. Lakavica, XIV. Valandovo, XV. Slavica, XVI. Kocani, XVII. Pehcevo, XVIll. Strumica, XIX. Dojran. Volcanic areas: a. Zletovo, b. Vitacevo, c. Sopur, d. Venae, e. Pehcevo - Zeravina and development of new border faults which cutting faults of meridional and equatorial represent natural borderlines between these strikes. It is a neotectonic depression that sub­ morphostructural units. The orientation of ex­ sided several hundred meters during the Neo­ tensive system of the development of neo­ gene, and was filled in by Pliocene limnic sedi­ tectonic morphostructures of subsidence ma­ ments and Quaternary layers. The valley is de it possible (Jancevski, 1987) to distinguish fairly reduced since the Pliocene layers were the Western-Macedonian province with pre­ affected by processes of uplift in the marginal dominant graben orientation of N - S and the parts whereas the central parts (particularly to province of Central and eastern Macedonia the south) were affected by continuing subsid­ with graben orientation of E - W strike. ence. The Pelagonian, Kicevo and Porec depres­ The fault zone in which the River Treska sions belong to the Western-Macedonian prov­ flows from west to east is regarded as the major ince. They represent grabens located between fault zone (Jamski fault). It represents the tec­ horst morphostructures (Fig. 2). tonic boundary of the depression in the south The Kicevo depression is associated with bordering the Ilin and Ljuben blocks (Fig. 2). subsidence of the terrain in the zone of cross- The second important fault has a N - S strike, 51 Table 1 Neotectonic faults in the area of Pelagonia, Kicevo and Porec depressions (after Jancevski, 1987) <a u 8 c '--o <!) c<!) ..... ·e- 0 Cl) 0. II) c ~ c Cl)... E . ~ 'E > Cl) .Q -o E :> ~ II) o- ~ ..... E 8. II) ... ci .:! Oil u ~ 0 II) E co u c c <!) ..c Cl) u ;:: ~tE z 2 i) ='..c li'o -o.,!;! <!) ·= >. c < 0 .... c 0.. <a u - <!) 2 c Vi c c <!) · - <I) (J 0 0 <!)"" <!);1: e ·- ..J o..:o ' Ql) 0:: c a.. E II) < 0:: Porecko- conlrasl firs! I gravilalional sao ss sao longiludinal reaclivaled Kru ~evski order medium lhird 2 Daulicki gravilalional sao 7 600 diagonal reac1iva1ed _pronounced order medium lhird 3 Topolcanski gravilalional 55° IS 250 diagonal reaclivaled pronounced order medium lhird 4 Jamski gravilalional sso 55 200 lransverse reaclivaled pronounced order medium lhird 5 Dj avalski gravilalional sao 7 200 lransverse reaclivaled pronounced order firs! newly 6 Bi!olski gravilalional 75° conlrasl 30 2600 longitudinal order formed medium lhird newly 7 Selecki gravi lalional 50° 50 longiludinal pJonounced sao order formed Brod- poorly lhird newly 7A gravilalional - - 70 longiludinal Negolino pronounced order formed poorly lhird newl y s Nebregovski gravilalional 65° 16 200 longitudinal pronounced order formed medium lhird newl y 9 Prilepski gravilalional sso 35 700 longitudinal pronounced order formed poorly lhird newly 10 Barbaraski gravilalional 65° 16 200 longitudinal pronounced order formed lhird newly II Jakupicki gravilalional S5° comrasl 3S 900 longiludinal order formed poorly lhird cwly 12 Cerski gravilalional 23 ISO longiludinal - pronounced order formed medium lhird newly 13 Zajaski