Neogene–Quaternary structures in the border zone between Alps, Dinarides and Pannonian Basin (Hrvatsko zagorje and Karlovac Basins, Croatia)

Abstract

Analysis of Neogene±Quaternary structures from seismic lines, surface measurements and geological-mapping is presented from the border zone between the Alps, Dinarides and Pannonian Basin. First, Early Miocene extension was possibly characterised by ENE directed extension. It was partly synchronous with NW±SE shortening. Second, Middle Miocene extension was possibly characterised by NW±SE to WNW±ESE directed extension. Again, this event was followed by a new generation of thrusts related to end-Sarmatian shortening. The last, Late Miocene E±W to WNW±ESE directed extension was followed by a final shortening that created major, map-scale folds, basement pop-ups and inverted former basins. Geometry, onlap and thickness patterns of the youngest syn-tectonic basin fill indicate that this last, N±S to NW±SE directed shortening started in Late Pontian and continued up to the present time. When taking into account the wider surrounding area, it seems that the structures related to this latest shortening are arranged in often perpendicular directions, centred at the eastern end of the Periadriatic lineament. To explain this fan-like pattern of synchronous shortenings a kinematic model is proposed combining counter-clockwise rotation with north-or northwestward shift of the Dinaridic block with respect to the more stable Alpine buttress.

Identification of tectonically active areas using DEM: a quantitative morphometric analysis of Mt. Medvednica, NW Croatia

“…Nev er the less, the re sults that point to partly tec toni cally induced re ju ve na tion of streams in this area are in good agreement with the struc tural lo ca tion of the south west ern seg ment of the NMBF which is in ter preted as tec toni cally ac tive by fold ing and fault ing of basal Plio cene-Qua ter nary strata along it, and by a neg a tive grav ity anom aly po si tioned in the front of the south west ern ter mi na tion of the moun tain (Kuk et al, 2000;Tomljenoviae and Csontos, 2001;Verbiè, 2005).…”

“…The fi nal stage in the for ma tion of these folds, which com menced dur ing the lat est Mio cene (ca. 6 Ma) un der a N-S to NW-SE di rected short en ing, is well-doc umented by out crop struc tural anal y ses and seis mic re flec tion data (e.g., Fodor et al, 1998;Gosar, 1998;Prelogoviae et al, 1998;Vrabec, 1999;Tomljenoviae and Csontos, 2001). In ad dition to fold ing, the short en ing was ac com mo dated by per va sive brit tle de for ma tion and the for ma tion of E-W-strik ing re verse faults.…”

“…Medvednica (Verbiè, 2005), and by fold ing and pre sum ably fault ing of the basal Plio cene-Qua ter nary strata along the North ern Medvednica Bound ary Fault, as ob served in seis mic sec tions (NMBF in Fig. 2; Tomljenoviae and Csontos, 2001). Based on these stud ies, this area is con sid ered to be tec toni cally ac tive, with low up lift rates of ca.…”

“…Medvednica and the hilly ter rain to the north of it, which ex tends into Slovenia (Zagorje Re gion), is strongly con trolled by the pres ence of Late Mio cene-Qua ter nary folds and pop-up struc tures (e.g., Takšiae, 1965;Šimuniae et al, 1983;Tomljenoviae and Csontos, 2001). These struc tures mark the east ward pro lon ga tion of the Sava folds re gion of Slovenia (Sikošek, 1971;Placer, 1999), a zone of ac tive E-W to NE-SW-trending ranges (anticlines) and valleys (syn clines; Fig.…”

“…Medvednica drain age bas ins that we then com pared to sepa rate those rep re sent ing tec toni cally ac tive vs. in ac tive sub-areas. These new data were then com pared with the re sults from pre vi ous geomorphologic, neotectonic and seismotectonic stud ies of this area (Heaeimoviae, 1984(Heaeimoviae, , 2000Prelogoviae et al, 1998;Tomljenoviae and Csontos, 2001;Tomljenoviae et al, 2008;Herak et al, 2009). …”