engleski

Kinematics of thrust belt development in the external Dinarides, Croatia

Many compressional orogenic systems include foreland fold-and-thrust belts, but the relationship between foreland thrust belt kinematics and hinterland crustal thickening, and their dependence on numerous additional factors such as variable accretionary flux, fault friction, surface processes, crustal flow, and pre-existing structure remains controversial. The Dinaric orogen may provide an important opportunity to isolate the relative importance of some of these factors. The external Dinarides are composed primarily of carbonate strata. Their insensitivity to climatic variability may potentially mitigate this important source of uncertainty relative to many other fold and thrust belts. As a first step toward understanding the kinematics of the external Dinarides, we measured present-day crustal velocity along a N13°E profile across the southern Adria microplate and external Dinarides collision zone. We used these data to develop an elastic dislocation model representing contemporary fold and thrust belt kinematics and decollement geometry. At the latitude of the Dalmatian Islands, the model fault plane reaches the surface some 80~km seaward of mapped SW-verging thrusts of Eocene and perhaps Neogene age along the coastal areas, consistent with SW-migrating deformation in an active fold and thrust belt. South of the Dalmatian Islands, however, the modern deformation front appears to be located within about 1~km of the older mapped faults. The largest known earthquakes in the system (~M7) are associated with this southern stationary-width part of the system. Possible explanations for along-strike variability in thrust belt kinematics include along-strike changes in decollement friction, clastic sediment availability and drainage network connectivity, accretionary flux associated with variable Adria carbonate platform thickness, retroarc exhumation, and subaerial distribution of pro-wedge carbonates.

southern Adria microplate; Dinarides; Croatia; elastic dislocation model

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