The Sistiana Fault and the Sistiana Bending Zone (SW Slovenia)

The Sistiana Fault is an alleged disjunctive deformation of Microadria in the sea bottom of the Gulf of Trieste. Onshore, it is visible only in the Sistiana Bay, but towards the northeast it soon pinches-out, in structural-geometric terms it diminishes soon after the crossing of the thrust boundary of the Dinarides, or the Istrian-Friuli Underthrustig Zone, respectively. Further to the northeast, only the bending zone is developed in the External Dinarides, which stretches all the way from the Sistiana Bay to the Idrija-Žiri area. We named it the Sistiana Bending Zone. Its direction can be determined based on geological maps and is around 60°, so we conclude that the Sistiana Fault should extend approximately in this direction. In the bending zone, the Trieste-Komen Anticlinorium, the Vipava Synclinorium, the Trnovo Nappe opposite to the Hrušica Nappe and the Raša and Idrija Faults are laterally bent. The size of the bend is the largest in the Sistiana Bay, and in the east-northeast direction it decreases linearly. The general geological circumstances suggest that the Sistiana Fault has not been recently active.

Phytosociological analysis of noble hardwood forests (Ostryo-Tilienion platyphylli) in the Karst and its neighbouring regions (SW Slovenia)

In SW Slovenia, at Gora under Železna Vrata and Petnik gorge near Branik – both on the northern edge of the Karst, in the collapse doline Orleška Draga at Sežana and under Brkinski Rob at the contact of the Karst and Brkini Hills, we conducted a phytosociological analysis of the stands whose tree layer is dominated by Tilia platyphyllos, T. cordata, Acer pseudoplatanus, Ulmus glabra, in places also Carpinus betulus and Ostrya carpinifolia, and classified them into three associations, Corydalido ochroleucae-Aceretum pseudoplatani, Paeonio officinalis-Tilietum platyphylli and Fraxino orni-Aceretum pseudoplatani. The latter was described as a new. Also new is a secondary large-leaved lime association Lamio orvalae-Tilietum platyphylli on the sites of montane beech forests (Lamio orvalae-Fagetum) in the Čepovan valley, at the contact of the Dinaric and sub-Mediterranean phytogeographical regions of Slovenia.

Localities and sites of the neglected umbellifer Physospermum verticillatum (Apiaceae) on Mt. Slavnik in southwestern Slovenia / Nahajališča in rastišča prezrte kobulnice Physospermum verticillatum (Apiaceae) na Slavniku v jugozahodni Sloveniji

On the shady (northern) slopes of Mt. Slavnik (Slavnik mountains, Čičarija, SW Slovenia) we identified Physospermum verticillatum (Apiaceae), a species whose northernmost known sites in its entire distribution area had until then been in the Croatian part of Čičarija near the border with Slovenia (Žbevnica near Dane). It occurs mainly in beech stands from the association Seslerio autumnalis-Fagetum, frequently in smaller gaps, on forest edges and road banks, where it occurs in fringe communities (Calamintho grandiflorae-Physospermetum verticillatinom. prov.), at elevations spanning 800 m to 1000 m. The plants are vital, most of them develop flowers and fruit. Although it is justified to assume that it may occur elsewhere in the Slovenian part of Čičarija, we propose it be classified in the Red List as rare. Key words: flora, Physospermum verticillatum, vegetation, Seslerio autumnalis-Fagetum, Čičarija, Istria, Slovenia Izvleček Na osojnih (severnih) pobočjih Slavnika (Slavniško hribovje, Čičarija, jugozahodna Slovenija) smo našli vrsto Physospermum verticillatum(Apiaceae), ki je do zdaj imela najbolj severna znana nahajališča v svojem celotnem arealu v hrvaškem delu Čičarije blizu meje s Slovenijo (Žbevnica pri Danah). Raste predvsem v bukovih sestojih iz asociacije Seslerio autumnalis-Fagetum, pogosto v manjših vrzelih, tudi na gozdnem robu in cestni brežini, tam v robnih združbah (Calamintho grandiflorae-Physospermetum verticillatinom. prov.), na nadmorski višini od 800 m do 1000 m. Rastline so vitalne, večinoma cvetijo in plodijo. Kljub temu in upravičeni domnevi, da v slovenskem delu Čičarije lahko raste tudi drugod, jo predlagamo kot redko za uvrstitev na rdeči seznam. Ključne besede: flora, Physospermum verticillatum, vegetacija, Seslerio autumnalis-Fagetum, Čičarija, Istra, Slovenija

Stratigraphic constraints on the Jurassic carbonate platform succession of Trnovski Gozd, SW Slovenia: Strontium isotope dating of brachiopods and belemnites

<p>Jurassic successions of the northern part of the Friuli (a.k.a. Dinaric or Adriatic) Carbonate Platform (hereinafter FAD) are best exposed along the Trnovski Gozd Plateau in SW Slovenia. A major stratigraphic unit, known as the Trnovo (Ternowaner) oolite has been considered as a classical, textbook example of a highly productive carbonate platform system exporting oolite sediments to the adjacent deep water depositional settings, producing massive bodies of resedimented oolite, such as the Vajont Limestone of the Belluno Basin. Whereas the stratigraphy of the basinal units in the eastern southern Alps and NW Dinarides is well constrained, coeval shallow marine depositional sequences of FAD Carbonate Platform lack a reliable chronostratigraphic framework.</p><p>We performed Sr isotope analysis of brachiopod shells and belemnite rostra from two stratigraphic levels at the base and above the Trnovo oolite unit (TOU). Suitability of the fossil material was controlled by selecting skeletal parts without fractures and lacking evidence of alteration due to diagenesis and weathering. The ultrastructure of specimens was inspected in resin-embedded polished thin sections under a petrographic microscope, supported by cathodoluminescence and SEM examination, including EDS semi-quantitative elemental analysis of skeletal parts in thin sections and slabs. For chemical analysis, powdered samples were drilled from thin section wafers and analysed for <sup>87</sup>Sr/<sup>86</sup>Sr (stratigraphy), d<sup>13</sup>C, d<sup>18</sup>O, Ca, Mg, Sr, Fe, Mn and Rb (diagenetic alteration control).</p><p>The elemental quantification was performed at Jožef Stefan Institute on an Agilent 8800 Triple-Quad Mass Spectrometer and Sr isotopic analysis on a Nu plasma II Multi-Collector MS. Additional <sup>87</sup>Sr/<sup>86</sup>Sr measurements were performed at UCM Madrid on a IsotopX TIMS. The numerical values were calculated from published Sr curves.</p><p>Brachiopod species from a lumachelle directly overlying a condensed interval in the base of TOU have been considered indicative for the early Toarcian. However, <sup>87</sup>Sr/<sup>86</sup>Sr values obtained from rynchonellid brachipod shells ranged from 0.707109 to 0.707122, corresponding to numerical ages of either 184.7 ± 0.4 Ma (late Pliensbachian) or 181.8 ± 0.5 Ma (early Toarcian). Belemnites from the Limestone with chert, an informal unit overlying TOU, yielded <sup>87</sup>Sr/<sup>86</sup>Sr values from 0.706838 to 0.706862, that fit two intervals of the Sr isotope curve, i.e., 162.5 ± 1.9 Ma (latest Callovian-early Oxfordian) and 159.4 ± 1.7 Ma (middle to late Oxfordian), respectively. In both cases, the duality in results is caused by their proximity to the Sr curve minima.</p><p>These ages open several important questions about the geometry and depositional history of the northern FAD platform system. Despite of a limited accuracy of our results, the age range for TOU clearly spans (at least) late Toarcian and almost whole middle Jurassic, while the age of the supposedly time-equivalent basinal unit, the Vajont Limestone, falls into the late Bajocian-Bathonian interval. Furthermore, our sedimentological re-examination of the classical TOU localities has not shown characteristics of in-situ oolite production environments but, on contrary, evidence of deeper marine deposition marked by beds of carbonate mudstone, including most typical rosso-ammonitico-type facies, associated with (resedimented) oolite and crinoidal facies, similar to parts of the succession of the Vajont Limestone.</p>

Flowstones from the Račiška Pečina Cave (SW Slovenia) Record 3.2-Ma-Long History

Establishing a chronology of events is a critical step in reconstructing the palaeoclimate and it is important for all types of environmental records, including speleothems. Here, we analysed a unique series of flowstones deposited between 3.2 Ma (marine isotope stage (MIS) Km3) and 0.08 Ma (MIS 5). The studied flowstones are located in a classic karstic environment, the Račiška Pečina Cave in south-western Slovenia. Further, a detailed chronology of events was constructed based on oxygen isotope stratigraphy (OIS), combined with magnetostratigraphy and U-series dating. Two curves were selected as reference records where the LR04 record was used as the global curve and a Mediterranean record was used as the regional curve. The Račiška Pečina profile was divided into two segments separated by a principal disconformity. The lower segment correlated better with the regional Mediterranean curve, while the upper segment was with the global LR04 curve. These findings suggest that the main factors controlling environmental conditions in the cave area changed between 3.2 and 0.8 million years ago.

Pomen varovanja vročih točk geodiverzitete za ohranitev biotske pestrosti na območju Nature 2000 v dolini reke Dragonje

Namen prispevka je na varovanem območju Natura 2000 ovrednotiti geodiverziteto in podati smernice za vključitev v obstoječi sistem naravovarstva. Kot območje preučevanja je bilo izbrano porečje Dragonje. Na podlagi kartografskega gradiva in terenskega dela smo izdelali morfografski zemljevid območja, s pomočjo literature pa prilagodili metodo izračuna indeksa geodiverzitete v geografskih informacijskih sistemih. Končni rezultat je zemljevid indeksa geodiverzitete, na podlagi katerega smo določili vroče točke geodiverzitete. // The importance of protection of geodiversity hotspots for the conservation of biodiversity in the Natura 2000 area in the Dragonja river valleyThe purpose of the article is to evaluate geodiversity in Natura 2000 protected area and to provide guidelines for inclusion in the existing nature protection system. The Dragonja River basin (SW Slovenia) was selected as a study area. Based on cartographic material and field work we made a morphographic map of the area, and based on the literature we adjusted the method of calculating the geodiversity index in geographic information systems. The final result is a map of the geodiversity index, on the basis of which geodiversity hotspots were determined.