Jože Čar

Miocene‐Pliocene tectonic evolution of the Slovenian Periadriatic fault: Implications for Alpine‐Carpathian extrusion models

The Periadriatic Line (PAL) is a remarkable, several hundred kilometer long fault system of the Alpine orogen. Its dextral character was documented by several authors using diverse criteria, but detailed kinematics and timing of movements had not been investigated along its whole length. Structural and paleomagnetic measurements, mapping, and stratigraphic and sedimentological studies have helped to unravel the Miocene-Pliocene evolution of the Slovenian segment of the PAL. Brittle deformation was characterized by NW-SE to N-S compression and perpendicular tension. Deformation has resulted in dextral strike-slip faulting, folding, and tilting of beds. The first transpressional event corresponds to the first phase of lateral extrusion of the East Alpine-Western Carpathian-Northern Pannonian block in the early Miocene (24–17.5 Ma). After a short period of transtension during the Karpatian (17.5–16.5 Ma), dextral transpression reoccurred during the middle Miocene to Pliocene and lasted up to the Quaternary. Middle Miocene dextral slip can be connected to the second phase of extrusion. The highly deformed rocks within the dextral shear zones show variable clockwise, sometimes counterclockwise, rotations. The mechanism of rotation seems to be complex, ranging from regional rotation to local folding due to pure or simple shear (domino-type rotation).

Upper Ladinian to Lower Carnian sedimentary evolution in the Idrija-Cerkno Region, Western Sovenia

SummaryAn Upper Ladinian to Lower Carnian succession in the Idrija-Cerkno region (W Slovenia) is described and correlated with similar successions in the Dolomites. Structurally, the area belongs to the Rodne unit (Trnovo nappe, NW Dinarides). The succession was reconstructed from three stratigraphically superimposed sections.The Orehovska Grapa section is characterised by finegrained turbidites composed of sandy mudstones with intercalations of lenses and beds of trachy-andesite tuff and resedimented tuffs. Beds of hemipelagic light grey wackestone are rarely interstratified. These rocks are correlative with the Upper Ladinian Wengen Group.The Police1 section is composed of black shaly marls and mudstones, hemipelagic wackestone, tuffaceous sand-stones, and in the upper part, of calciturbidites overlain by black laminated shales. The section is correlated with the lower part of the San Cassiano Formation.The Police 2 section consists mainly of wavy bedded peloidal and bioclastic limestone, alternating with thin interbeds of shaly mudstones and marls. The limestone and mudstones are interpreted as tempestites and gradually pass into bedded and massive dolomite of Early Carnian age. This succession is similar to the transition from the San Cassiano Formation to the Cassian Dolomite.The studied succession represents a shallowing upward basinal sequence capped by carbonate platform deposits. Palaeogeographically it is a Late Ladinian transition from the carbonate platform in the south to the typical basinal area in the north.

Carnian reefal blocks in the Slovenian Basin, eastern Southern Alps

The Carnian Amphiclina beds of the eastern Southern Alps mostly consist of shale and sandstone deposited in the deep-marine Slovenian Basin, which was located near the western margin of the Meliata Ocean. In the vicinity of Cerkno (Slovenia), blocks of massive or crudely bedded limestone crop out within a succession of clastic rocks that are several hundred meters thick. Sponge-microbialite boundstone and coral pillarstone are the predominant facies within these blocks. Oncoid floatstone-rudstone and moderately sorted peloid packstone form crudely layered parts of the blocks, whereas intraclast-cortoid packstone and poorly sorted peloid packstone occur locally in cross-stratified thin beds, truncated at block margins. Detailed mapping further shows that limestone blocks form units at discrete stratigraphic levels within shale and that these units are variable in thickness. Whereas the largest blocks mostly lie concordant to the bedding, smaller blocks are poorly sorted and randomly oriented. All of this evidence suggests that the limestone blocks are olistoliths, derived from an outer platform margin and/or uppermost slope.