The Alpine Late Collisional Rila-Rhodope Metallogenic Zone of the Balkan Orogenic System
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СПИСАНИЕ НА БЪЛГАРСКОТО ГЕОЛОГИЧЕСКО ДРУЖЕСТВО, год. 80, кн. 1, 2019, с. 55–79 REVIEW OF THE BULGARIAN GEOLOGICAL SOCIETY, vol. 80, part 1, 2019, p. 55–79 The Alpine late collisional Rila-Rhodope Metallogenic Zone of the Balkan Orogenic System Kamen Popov, Petko Popov University of Mining and Geology “St. Ivan Rilski”, Department of Geology and Exploration of Mineral Deposits, 1 Prof. Boyan Kamenov str., Studentski Grad, 1700 Sofia, Bulgaria; E-mail: [email protected] Алпийската късноколизионна Рило-Родопска металогенна зона в Балканската орогенна система Камен Попов, Петко Попов Минно-геоложки университет „Св. Иван Рилски“, Катедра „Геология и проучване на полезни изкопаеми“, Студентски град, ул. „Проф. Боян Каменов“ № 1, София 1700 Резюме. В еволюцията на Балканската орогенна система, като част от Алпо-Хималайския пояс, се проявява стадий на коли- зионни процеси, обхващащи врeмето от Mастрихта до Лютеса. В северните части на системата е разположено субекваториалното Кула-Обзорско предпланинско понижение с палеоцен-лютеска плиткоморска ритмична моласа, а на юг – бартон-плиоценски континентални наслаги. В южните части на орогенната система се внедряват плутони, обособени като горномастрихт-лютески Рилo-Родопски комплекс, вместени в метаморфитите от фундамента. Колизионният стадий завършва с илирските гънкови и възседно-навлачни деформации. Металогенните процеси са свързани с горномастрихт-лютеския магмен комплекс. Образувана е поредица от рудни находища, определящи позицията на Рило-Родопската металогенна зона. Те се характеризират с преоблада- ващото развитие на хидротермални руди на волфрам, молибден, уран и на флуорит. Освен това присъстват железни, злато-анти- монови, бисмутови и по-рядко полиметални, злато-полиметални и медни минерализации. Често те са с близки пространствени, темпорални и минeрало-геохимични връзки. Очертават се Рило-Западнородопският, Ракитовско-Бачковският и Барутинско- Смилянският руден район, в които се обособяват отделни рудни полета или рудни минерализирани площи. Ключови думи: Балканска алпийска система, илирска колизия (Лютес), горномастрихт-лютески гранитоиден комплекс, Рило-Родопска металогенна зона, W, Mo, флуоритови, U и Sb (+Au) находища. Abstract. During the Late Maastrichtian to the Lutetian time, a stage of collisional processes has occurred in the evolution of the Balkan Orogenic System, which is a part of the Alpine-Himalayan belt. The subequatorial Kula-Obzor Foredeep with Paleocene–Lutetian shallow marine rhythmic molasse is situated in the northern parts of the system, while the Barthonian–Pliocene continental sediments are deposited to the south. Paleocene–Lutetian plutons are developed in the southern parts of the orogenic system and they are nominated as Rila-Rhodope Upper Maastrichtian–Lutetian complex, intruded within the metamorphic rocks of the basement. The collisional stage ter- minates with the Illyrian fold and thrust-nappe deformations. The metallogenic processes are related to the Upper Maastrichtian–Lutetian magmatic complex. Numerous ore deposits are formed, thus defining the position of the Rila-Rhodope metallogenic zone. They are characterized by the predominant development of hydrothermal W, Mo, U ores and fluorite. Fe, Sb (+Au), Bi, and rarely polymetallic, Au-polymetallic and Cu mineralizations are represented as well. Often they are in close spatial, temporal and mineralogical-geochemical relations. Rila-Western Rhodope, Rakitovo-Bachkovo and Barutin-Smilyan ore regions are defined and individual ore fields or mineral- ized ore areas are differentiated within them. Keywords: Balkan Alpine System, Illyrian сollision (Lutetian), Upper Maastrichtian–Lutetian granitoid complex, Rila- Rhodope metallogenic zone, W, Mo, fluorite, U, Sb (+Au) deposits. Introduction continental blocks. The Balkan, Srednogorie and Morava-Rhodope Zones are situated between the The Balkan Orogenic System (the Balkanides) is a Moesian Platform and the Vardar suture (Dabovski, part of the Alpine-Himalayan belt and it is formed Zagorcev, 2009). Practically, all researchers agreed in the active SE margin of the Paleo-European that the Balkan tectonic system is developed along continent, subparallel to the Vardar Paleo-ocean the NE continental board of the Vardar Paleo-ocean, (Fig. 1). The evolution of the tectonic system is and the southern flank of the Moesian Platform. marked by sequence of tectonic events leading to Different authors distinguish subsequent stages of the paleo-ocean’s closure and collision between the ocean rifting, subduction and Austrian collision, 55 Fig. 1. Geologic scheme of Bulgaria for the Alpine collisional stage (Maastrichtian–Lutetian) 1, epicontinental Bartonian–Quaternary sediments; 2, Paleocene–Lutetian granitoid rocks; 3, Paleocene–Lutetian foothill sedi- ments; 4, Mesozoic basement; 5, Paleozoic–Neoproterozoic basement; 6, Krumovgrad terrigenous continental basin; 7, Kula- Obzor Foredeep Фиг. 1. Геоложка схема на България за алпийския колизионен етап (Мастрихт–Лютес) 1 – епиконтинентални бартон-кватернерни отложения; 2 – палеоцен-лютески гранитоидни скали; 3 – предпланински па- леоцен-лютески седименти; 4 – мезозойска подложка; 5 – палеозой-неопротерозойски фундамент; 6 – Крумовградски теригенен континентален басейн; 7 – Кула-Обзорско предпланинско понижение Late Cretaceous mantle-crustal magmatism with purposes. The ore deposits are characterized and Sub-Hercynian and Laramian deformations, late related to the metallogenic units of different rank, Maastrichtian–Eocene collision and post-collision- based on the metallogenic analysis of existing pub- al orogeny in the evolution of the Balkan System lished and National Geological Fund data. (Boyanov et al., 1989; Dabovski et al., 1991, 2002; Popov, 1996, 2002; Dabovski, Zagorcev, 2009). The late Maastrichtian–Eocene collision is marked Tectono-magmatic characteristics by foredeep in the Balkanides, isolated continental basins to the south and granitoid magmatism in the The late collisional stage in the Alpine-Balkan Oro- Morava-Rhodope Zone and the subsequent Illyrian genic System evolution is characterized by tangen- compression. The Rila-Rhodope Metallogenic Zone, tial compression, which commence by the end of the with specific mineralization, is formed in relation to Late Cretaceous (Maastrichtian) and terminates in the magmatism. The purpose of this study is to dif- the middle Eocene (Lutetian). The collision is char- ferentiate the mentioned magmatism in the Balkan acterized by formation of fold-thrust structures in evolution and to focus on the associated ore depos- association with the granitoid magmatism, specific its and occurrеnces for the ore potential prognosis sedimentation and high-grade metamorphism. The 56 sedimentation is marked by the rhythmic molasses plutons are exposed in the southern parts of West- in the Kula-Obzor Foredeep, as well as by the conti- ern Rhodopes and they are composed of porphyroid nental deposits in the Eastern and Central Rhodopes and aplitoid granite (Kozhoukharov et al., 1963f1; Mts, Eastern Stara Planina Mt., the strip between Soldatos et al., 2008; Dabovski et al., 2009). The the towns of Kazanlak and Burgas, Panagyurishte Yugovo pluton extends in the northern parts of the and Central Stara Planina Mt. (Juranov, Pimpirev, Central Rhodopes and it is represented by several 1989; Goranov, Atanasov, 1992; Juranov, 1992; bodies, composed of quartz-monzodiorite, granodi- Sin nyovsky, Sultanov, 1994; Kânčev, 1995; An- orite and monzogranite (Kožuharova, Kožuharov, gelov et al., 2008, etc.). Simultaneously, a series 1962). Obviously, the Dobralak granodiorite, situat- of Maastrichtian–Lutetian granitoid plutons are in- ed NW from the village of Narechenski Bani is also truded in the southern area of the Balkan Orogenic a part of the same group (Kožuharova, Kožuharov, System, in part of the Morava-Rhodope Zone, 1962). The small Topolovo granodiorite pluton is within the Rila and Rhodopes. Thus, a collisional defined to the South from the town of Asenovgrad magmatic arc originated from the hinterland mar- (Marchev et al., 2013). Numerous small stock-like gins. Fragments of the basement in the area are rep- and dyke-like granite bodies are exposed in the resented by rocks of polyphase regional amphibolite northern parts of the Rhodopes, in the areas of the facies metamorphism, which is manifested in rela- towns of Velingrad, Batak and Mihalkovo, and they tion to the Neoproterozoic, Caledonian, Hercynian, should be included in the Maastrichtian–middle Eo- Cimmerian, Austrian, Illyrian and Pyrenean pro- cene magmatic complex. The Smilyan pluton, com- cesses (Jaranoff, 1960; Kozhoukharov et al., 1988; posed of leucocrate to aplitoid granite and located to Boyanov et al., 1990; Peycheva, von Quadt, 1995; the South from the town of Smolyan, is also related Peycheva et al., 1993, 2000, 2004, 2007; Burg et to this complex (Kozhoukharov et al., 1992; Rae- al., 1996; Ivanov, 2000; Ivanov et al., 2000; Liati, va et al., 2006; Kaiser-Rohrmeir et al., 2013). The Gebauer, 2001; Cherneva et al., 2002; Ovcharova small Pripek, Drangovo and Dolen plutons in the et al., 2002, 2003a, b; Arkadakskyi et al., 2003; area of the town of Zlatograd are composed of gran- Carrigan et al., 2003; Ichev, Pristavova, 2004; von ite with transition to granodiorite, quartz-diorite and Quadt et al., 2006, 2008; Bonev, 2006; Zagorchev, quartz-monzodiorite (Kozhoukharov et al., 1995). 2008; Sarov et al., 2008a, b; Dabovski et al., 2009; The Chuchuliga and Rozino granite plutons and nu- Bonev et al., 2010; Bonev,