Geology of Bulgaria
The geology of Bulgaria consists of two major structural features. The Rhodope Massif in southern Bulgaria is made up of Archean, Proterozoic and Cambrian rocks and is a sub-province of the Thracian-Anatolian polymetallic province. It has dropped down, faulted basins filled with Cenozoic sediments and volcanic rocks. The Moesian Platform to the north extends into Romania and has Paleozoic rocks covered by rocks from the Mesozoic, typically buried by thick Danube River valley Quaternary sediments. In places, the Moesian Platform has small oil and gas fields. Bulgaria is a country in southeastern Europe. It is bordered by Romania to the north, Serbia and North Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east. Geologic History & Stratigraphy Precambrian (before 538.8 million years ago) Archean rocks outcrop in the south and west of Bulgaria as part of an ultrametamorphosed polymetamorphic complex including low-grade migmatite, gneissoid granite, and anatexite. Marble, amphibolite and gneiss from the Proterozoic are found in the Rhodope Massif. During the Precambrian, the Variscan Thracian Suture was part of the Balkan-Carpathian ophiolite segment. This feature left behind a highly stratified obducted ophiolite island arc assemblage with tectonized peridotite, dunite, lherzolite, wehrlite