The Rhodope Zone as a primary sediment source of the southern Thrace basin (NE Greece and NW Turkey): evidence from detrital heavy minerals and implications for central‑eastern Mediterranean palaeogeography

Detrital heavy mineral analysis coupled witha regional geological review provide key elements to reevaluatethe distribution of the Rhodope metamorphiczone (SE Europe) in the region and its role in determiningthe evolution of the Thrace basin. We focus on theEocene–Oligocene sedimentary successions exposed inthe southern Thrace basin margin to determine the dispersalpathways of eroded crustal elements, of bothoceanic and continental origins, as well as their differentcontributions through time. Lithological aspects andtectonic data coupled with geochemistry and geochronologyof metamorphic terranes exposed in the area point to a common origin of tectonic units exposed in NW Turkey(Biga Peninsula) with those of NE Greece and SEBulgaria (Rhodope region). The entire region displays(1) common extensional signatures, consisting of comparablegranitoid intrusion ages, and a NE-SW sense ofshear (2) matching zircon age populations between themetapelitic and metamafic rocks of the Circum-RhodopeBelt (NE Greece) and those of the Çamlica–Kemer complexand Çetmi mélange exposed in NW Turkey. Detritalheavy mineral abundances from Eocene–Oligocenesandstones of the southern Thrace basin demonstratethe influence of two main sediment sources mostly ofultramafic/ophiolitic and low- to medium-grade metamorphiclithologies, plus a third, volcanic source limitedto the late Eocene–Oligocene. Detrital Cr-spinel chemistryis used to understand the origin of the ultramaficmaterial and to discriminate the numerous ultramaficsources exposed in the region. Compositional and stratigraphicdata indicate a major influence of the metapeliticsource in the eastern part (Gallipoli Peninsula) during theinitial stages of sedimentation with increasing contributionsfrom metamafic sources through time. On the otherhand, the western and more external part of the southernThrace margin (Gökçeada, Samothraki and Limnos)displays compositional signatures according to a mixedprovenance from the metapelitic and metamafic sourcesof the Circum-Rhodope Belt (Çamlıca–Kemer complexand Çetmi mélange). Tectonic restoration and compositionalsignatures provide constraints on the Palaeogenepalaeogeography of this sector of the central-easternMediterranean region.·