Geological-geophysical model of the part of the Timok Magmatic Complex

[S. Ignjatović]

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Geološko inženjerstvo - Geofizika / Geological engineering - Geophysics

Timočki magmatski kompleks (TMK) u geotektonskom smislu pripada KarpatoBalkanidima istočne Srbije, koji su deo Tekijsko-Dakijske jedinice. TMK je nastao tokom kontinuirane vulkanske aktivnosti, koja je trajala oko deset miliona godina i odvijala se generalno u tri faze (Zimmerman et al., 2008, Kolb et al., 2013, Banješević, 2006). Pomeranje vulkanskog fronta je išlo od istoka ka zapadu (von Quadt et al., 2002, 2003, 2007). Ovaj kompleks pripada tetijskom evroazijskom metalogenetskom pojasu u svetu poznat po ležištima bakra i zlata (Janković, 1990). U doktorskoj disertaciji su prikazani rezultati aeromagnetskih i gravimerijskih istraživanja, kao i 2D geološko-geofizičko modelovanje duž 5 odabranih profila. Na osnovu geofizičih podataka definisan je prostorni položaj magmatskih tela koja se ne vide na površini istražnog područja i definisani su odnosi magmatskih tela prema okolnim stenama. 2D geološko-geofizičkim modelovanjem utvrđeno je da magmatska tela imaju mnogo veće rasprostranjenje ispod površine, nego što je to do sada bilo poznato. Plutonit Valja Strž u odnosu na njegovu otkrivenost na površini terena ima znatno veće rasprostranjenje, a rezultati modelovanja ukazuju da ispod površine ovaj plutonit nastavlja svoje pružanje ka severu i jugu. Pružanje ovog plutonita ka jugu je veće od njegovog pruženja ka severu. Modeli pokazuju da geofizički definisana subvulkanska tela, koja se pretežno nalaze u centralnom, a manjim delom u zapadnom delu TMK, odgovaraju vulkanitima senonske starosti. Ove stene imaju veće rasprostranjenje u dubini, nego što je njihovo pojavljivanje na površini. U potpovršini postoje dve odvojene oblasti ovih stena, pri čemu svaka od njih ima širinu od oko 2.5-3 km, a u nekim delovima i preko 5 km. Rezultati modelovanja sugerišu da postoji blaga promena u sastavu stena ka zapadu, što se može dovesti u vezu s nešto nižim sadržajima silicije u vulkanskim stenama senonske starosti. Rezultati 2D geološko – geofizičkog modelovanja su značajni i sa aspekta definisanja plitkih pojava hidrotermalno izmenjenih stena. Utvrđeno je da je rasprostranjenje ovih stena veće u odnosu na ono što je do sada bilo poznato.

The Timok Magmatic Complex (TMC) belongs to the East Serbian CarpathoBalkanides which is part of the Tisza-Dacia Unit. The TMC was formed by continuous volcanic activity throughout the period of ten million years that developed in roughly three phases (Zimmerman et al., 2008, Kolb et al., 2013, Banješević, 2006). During this evolution the volcanic front continuously migrated from the east to the west (von Quadt et al., 2002, 2003, 2007). This complex is part of the Tethyan Eurasian metallogenic zone which is known in world for its ore deposits of cooper and gold (Janković, 1990). The results of aeromagnetic survey, gravity survey and 2D geological-geophysical model along 5 profiles are shown in this thesis. The location of unexposed magmatic bodes and special relationships with surrounding rocks in the survey area are determined by geophysical data. The 2D geological-geophysical model has shown that magmatic bodies had greater outspread beneath surface than it was known earlier. The Valja Strž pluton has a much larger extent than is observable from its surface exposures. The results of modelling shown that pluton continues towards the south and north. The outspread of this pluton is larger in the south than in the north. The model also revealed that the subvolcanic bodies, placed mostly in central part and partly in western part of the TMC, correspond to Senonian volcanics. These bodies are much more widespread in depth than they are exposed on the surface. Beneath the surface there are two separate subsurface regions of these rocks, each around 2.5-3 km in width and in some parts over 5 km. The results of the model suggested that there is also a gradual westward shift in composition which is evident from decreasing silica contents in the Senonian volcanic rocks. The results of 2D geological-geophysical model are significant from side of shallow occurrences hydrothermally altered rocks. It is confirmed that outspread of these rocks is much larger than it was known earlier.

Timočki magmatski kompleks, aeromagnetska istraživanja, gravimetrijska istraživanja, 2D geološko-geofizički model, Valja Strž, magmatsko telo

Timok Magmatic Complex, aeromagnetic survey, gravity survey, 2D geological-geophysical model, Valja Strž, magmatic body.

528.27:543.062 55:550.3/.83 551.763:552.32 (497.11)(043.3)

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