LATE CENOZOIC EXTENSION OF THE ALPINE COLLISIONAL OROGEN, NORTHEASTERN GREECE - ORIGIN OF THE NORTH AEGEAN BASIN

Authors
Citation
Da. Dinter, LATE CENOZOIC EXTENSION OF THE ALPINE COLLISIONAL OROGEN, NORTHEASTERN GREECE - ORIGIN OF THE NORTH AEGEAN BASIN, Geological Society of America bulletin, 110(9), 1998, pp. 1208-1226
Citations number
100
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary
ISSN journal
0016-7606
Volume
110
Issue
9
Year of publication
1998
Pages
1208 - 1226
Database
ISI
SICI code
0016-7606(1998)110:9<1208:LCEOTA>2.0.ZU;2-Z
Abstract
The Rhodope metamorphic core complex, exposed beneath the Strymon Vall ey detachment in northeastern Greece, comprises a platform carbonate s equence >5000 m thick intruded by Tertiary calc-alkaline plutons. The final thickening of the north Aegean Alpine collisional orogen in Pale ogene time and its Neogene-Quaternary extensional dismemberment in the backarc of the Hellenic subduction zone produced structures within an d above the Rhodope core complex that are related here to four success ive deformations. In early-middle Eocene time (D1), the Falakron marbl e series was subducted northeastward beneath the Serbo-Macedonian-West Thracian gneiss complex, a heterogeneous ophiolite-bearing high-grade metamorphic terrane that was accreted to southeastern Europe in Creta ceous time, The orogen began to extend on a northeast-southwest axis i n earliest Miocene time, evidenced in the Rhodope core complex by the emplacement of the Symvolon granodiorite ca. 21 Ma within a northwest- trending midcrustal coaxial rupture of the Falakron slab (D2). The Str ymon Valley detachment system succeeded the D2 Symvolon rupture and re lated structures, facilitating unroofing of the core complex and a tra nsition from ductile to brittle deformation ca. 16-3.5 Ma (D3), The Se rbo-Macedonian gneiss complex, the island of Thasos, and a supradetach ment basin were translated relatively southwestward as much as 80 lan in the D3 hanging wall. Balanced reconstructions of D2 and D3 displace ments predicate two new hypotheses concerning the Cenozoic tectonic ev olution of northeastern Greece. First, the southwest-vergent Thasos de tachment and northeast-vergent low-angle normal faults in the Olympos region may both have rooted in the coaxial Symvolon rupture zone to fo rm a bivergent early Miocene extensional system. Second, the Olympos a nd Falakron carbonate platforms may be correlative remnants of the sub ducted eastern margin of the Apulian microcontinent, implying that the ''Vardar zone,'' the putative Alpine suture, is a rootless ophiolite belt, and that segments of the Alpine suture are actually exposed over a zone as wide as 200 km, including the Rhodope province. Cumulative D2 and D3 stretching of greater than or equal to 100% created the nort h Aegean basin. The North Anatolian fault, which accommodates the west ward escape of Anatolia from the Pontide suture, propagated into the n orth Aegean region in late Pliocene time. Its offshore continuation, t he North Aegean Trough, transfers dextral strike-slip displacement int o extension to the north, principally expressed in northern Greece by the Thermaikos, Strymon, and Drama half grabens (D4).