Sediment fill and fault activity in the Mesta Basin (SW Bulgaria)

The NNW-SSE-oriented Mesta Basin (SW Bulgaria) is located between the Pirin and Rhodope massifs. The basin contains a thick Palaeogene-age succession comprising mainly siliciclastics and volcaniclastics deposited in a continental setting. Associated volcanic rocks were sourced from a series of volcanoes in the southern part of the basin. Analysis of the dip configurations within a series of stratigraphic sections across the basin reveals that there is a progressive decrease in the stratigraphic gradient from the older through to the younger stratigraphic levels, and that this probably resulted from the complex interaction of (1) the amount of sediment input in relation to the emergence of the volcanic system, and (2) the degree of rotation due to the possible listric detachment fault (i.e. Mesta Detachment).