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Investigating the Middle Triassic volcanic and volcaniclastic rocks in the External Dinarides (Croatia and Bosnia and Herzegovina) an undeveloped rift system has been determined. This rift system was formed as a back-arc extension in the north-western edge of Palaeotethys Ocean (Stampfli & Borel, 2002 ; Schmidt et al., 2008). Geochemical data (whole rock REE and trace element composition and EMP analysis on pyroxene and feldspar crystals and crystaloclasts of different volcanic and volcaniclastic facies) indicates calc-alkaline magma composition, characteristic for subduction zones and contamination by the crustal material. Therefore we interpret the development of Middle Triassic rift in the Dinarides as a back-arc rift area that was strongly influenced by the subduction of the Palaeotethys toward north that stared in Early Permian and lasted throughout the whole Triassic. The geotectonic history of this part of Tethys is described as follows: In the Upper Permian and Early Triassic the Dinarides were located in the western Palaeotethys. According to the palinspastic reconstructions (Haas et al., 1995 ; Scotese, 2002 ; Stampfli & Borel, 2002 ; Schmidt et al., 2008 ; Stampfli et al., 2013) this Palaeotethyan area represented a shallow bay resembling a vast epicontinental sea, in the Dinarides, interpreted as a broad epeiric ramp (Aljinović et al., 2015). In the southern part of this ocean rifting started in the Permian between the Cimmerian block and the southwest coast of Pangea. This rift system (Neotethys) advanced to the north and finally formed the Tethyan Ocean in the Jurassic. From afore mentioned palaeogeographic reconstructions it is notable that the subduction of Pelaeotethys persisted throughout the Triassic. This subduction process could have influenced the magma formation in the Middle Triassic. The former subduction, which caused the formation of Pangea could have also left the imprint on the Middle Triassic magma composition (Crisci et al., 1984). Palinspastic reconstructions place the area of the External Dinarides, and surrounding areas in the vicinity of earlier Gondwana and Laurasia suture line, the similar direction of the newly formed Tethyan rift. This caused the subduction of the Gondwana crustal material, and its partial melting that had great influence on the Middle Triassic magma in the western Tethys. Except the primary rifting direction there were additional extensional/rift systems in the continental part of Pangea. There were three recorded back-arc rift zones in the Middle Triassic: Meliata and Meliac Oceans, and the rift system directed across the Dinaridic and Alpine area. The area of the External Dinarides was bordered by the opening of the Tethyan Ocean from the southwest and opening of the Meliata and Meliac Oceans in the north. The External Dinaridic aborted rifting direction did not evolve because of these two compressive movements that forced its closure.

Srednje trijaski taložni okoliši Vanjskih Dinarida izrazito su diferencirani. Nakon stabilnog i mirnog donjeg trijasa, na području Vanjskih Dinarida tijekom anizika dolazi do intenzivne ekstenzijske tektonike, povezane s otvaranjem Tetiskog oceana. Za razliku od širokog, rasprostranjenog plitkog marinskog područja epikontinentalne rampe u donjem trijasu (Aljinović et al., u tisku), blokovska tektonika uzrokovala je spuštanje ili izdizanje pojedinih blokova, pri čemu su pojedini blokovi bili potpuno izdignuti i obilježeni kopnenom fazom u aniziku, dok je na području spuštenih blokova taloženje kontinuirano (Hrvatović, 2006). U dijelu diferenciranog prostora (Slovenski jarak i Unutrašnji Dinaridi) tijekom anizika nastaje dubokomorsko korito obilježeno kontinuiranim taloženjem tijekom čitavog trijasa. Tektonska aktivnost u srednjem trijasu praćena je i vulkanskom aktivnošću, o čemu svjedoče vulkanoklastične naslage srednjeg trijasa Vanjskih Dinarida i okolnih područja (Obenholzner, 1991, Marjanac, 2000, Belak, 2000). Vulkanoklastiti Vanjskih Dinarida iskazuju različita petrografska i genetska obilježja a time je i njihova korelacija izrazito složena. Za dosada istražene sljedove i tipove vulkanoklastita nije poznato jesu li su istovremeni ili stratigrafski različiti. Jedini podatak radiometrijskog datiranja srednje trijaskog vulkanizma u vanjskim Dinaridima do sada učinjen je na ignimbritima u okolici Brušana te je metodom K/Ar na feldspatima dobijen podatak od 243±1, 7 Ma što upućuje na anizičku starost no s mogućnošću odstupanja u rasponu od 1, 7 Ma a time i moguću donjo anizičku starost. U svrhu petrografskog i biostratigrafskog diferenciranja srednjetrijaskih vulkanoklastičnih naslaga Dinarida, na trima lokacijama u Vanjskim Dinaridima detaljno su snimljeni sljedovi naslaga, prikupljeni su uzorci za geokemijsku i biostratigrafsku odredbu (konodonti i amoniti). Navedene lokacije od sjevera prema jugu su Donje Pazarište, u okolici Gospića ; Bosansko Grahovo, u Bosni i Hercegovini, u blizini graničnog prijelaza Strmica ; i Zelovo, u okolici Sinja. Profil Donje Pazarište sastoji se od: sedimentacije flišolikog izgleda, izmjene šejlova, odnosno tufitičnih madstona i vulkanogenih grauvaka. Slojevi madstona s više karbonatne komponente često sadrže fosile tankoljušturastih školjkaša i radiolarija. U središnjem dijelu slijeda pronađen je primjerak amonita Flexoptychites sp. koji sugerira gornjo anizičku starost. Prema vrhu slijeda udio vulkanoklastičnog materijala se povećava, a pojavljuju se i slojevi nodularnih vapnenaca s vulkanoklastičnim materijalom. Slijede metarski slojevi kristaloklastičnih tufova i ignimbrita, koji prelaze u izrazito staljeni vitroklastične tufove. Na vrhu profila pojavljuju se pločasti slojevi vapnenaca u izmjeni s blijedozelenim tufovima. Vapnenci su pekstonskog do grejnstonskog tipa, s čestim nodulama rožnjaka. Profil Bosansko Grahovo sastoji se uglavnom od autoklastičnih vulkanskih stijena (Aljinović et al, 2010). Početak slijeda sadrži peperite - vapnence nodularna izgleda u kojima je vidljiva tekstura tečenja vulkanoklastičnoga materijala kroz nelitificirani vapnenački talog. Ovakav tip stijena, ukazuje na miješanje vulkanskog ili magmatskog materijala s vodom zasićenim, vlažnim sedimentom. Vapnenci su uglavnom biomikritnog tipa s tankoljušturastim školjkašima i radiolarijama. Vapnenački dio peperita poslužio je za konodontne analize. U uzorcima su određene dvije konodontne zone gornjeg anizika. (constricta zona - srednji ilirij i trammeri zona gornji ilirij). Na vrhu peperitnog facijesa nalazi se 1, 3 m debeli sloj staljenog ignimbrita veličine krupnog pijeska u kojem klasti plovučca i feldspata jasno ukazuju na imbrikaciju. Nakon toga, autoklastični facijes se nastavlja zelenim in situ hijaloklastitima s jasnom jig saw fit strukturom. Ovakve odlike svjedoče da su se bazaltni izljevi magme odvijali u dubljem morskom okolišu. Prema vrhu ovog facijesa jig saw fit struktura postaje poremećena rotacijom i pomicanjem klasta s primarnog položaja. Na kraju slijeda, u vulkanoklastičnom facijesu nalazi se sve više vapnenačkih klasta i klasta crvenih rožnjaka. Profil Zelovo sniman je na lokaciji poznatoj kao Mijića staje. Na ovom lokalitetu slijed je predstavljen izmjenom blijedozelenih do svijetlih rastresitih tufova i kompaktnih zelenih, često paralelno i koso laminiranih, kristaloklastičnih tufova. Između horizonata tufova nalaze se slojevi tamnih vapnenaca u kojima su uočene radiolarije, školjkaši, ali i ostaci fosilnih kopnenih biljaka, Equsitites. U slojevima vapnenaca vidljive su i strukture slampiranja. Na ovom lokalitetu konodontne su analize prema Jelaska et al., (2003) ukazale također na starost gornjeg anizika. Neposredno ispod i iznad pojave horizonata tufova zabilježena je hungaricus zona, a prema tzv. “otarničkim brečama“, kojima započinje anizik na ovom dijelu Vanjskih Dinarida, zabilježene su još trammeri zona i constricta zona (Jelaska et al., 2003). Unatoč bitno različitoj petrogenezi srednjetrijaskih vulkanoklastičnih naslaga tri istražena lokaliteta, biostratigrafski podaci dobiveni analizom konodonata i amonita ukazuju na starost gornjeg anizika na sva tri lokaliteta. Vulkanoklastični događaji slične starosti zabilježeni su i u okolnim područjima pr. Unutrašnji Dinaridi (Hrvatović, 2006), planina Bükk u Mađarskoj (Vellendits, 2004), Južnim Alpama (Celarc et al., 2013, Crisci et al., 1984). Imajući u vidu i dobiveni rezultat apsolutne starosti, vrijeme taloženja sva tri istražena slijeda moglo bi odgovarati početku constircta zone (prema Ogg et al., 2008). To bi značilo da su vulkanoklastični facijes Donjeg Pazarišta na temelju amonita, brušanski ignimbritni facijes određen radiometrijskim datiranjem, i autoklastični facijes Bosanskog Grahova stratigrafski jako bliski, moguće istovremeni. Vulkanoklastični materijal profila Zelovo je nešto mlađi i odgovara konodontnoj hungaricus zoni, odnosno donjem ladiničkom katu fasaniju jer su u vapnencima u podini tufa na profilu Zelovo definirane starije constiricta i trammeri zone konodonata, što potvrđeno i amonitima (Balini et al, 2006).

The Croatian coastal region is a part of Maritime Dinaric Alps which and coincides with the Adriatic Carbonate Platform (AdCP). The some of the coastal karst depressions developed into larger lakes, although not numerous (

The Neogene to Quaternary Lake Pannon sedimentary successions of the SW part of the Pannonian Basin are characterized by three 2nd order megacycles divided by major regional unconformities. In here described sediments are related to the transtensional post-rift thermal basin subsidence and belong to the second megacycle between the Base Pannonian to the Base Pliocene unconformity For the interpretation of the genesis and evolu-tion of the wider depositional area around the recent gas field Legrad in the NW Croatia inter- disciplinary approach were used. Information on lithology, ichnology, sedimentary structures and structural elements were obtained from complete macroscopic examination of cores. Petrophysical and calcimetry measurements, detailed petrographical (and microporosity) and palynological analyses were done. Geochemical evaluations were considered. All available well data were correlated and calibrated with well log and seismic data. Paleorelief features (like channel position and their direction) are visible on coherency time-slices.Investigated deposits and related cores are presented by alteration of sandstone, siltstone and marls. Sandstones, generally lithic arenites, are very well cemented with intergranular porosity. They are moderately sorted, with grains in the range from very fine to medium sand size. Sandstones are sporadically rich in organic matter. Siltstone is also well cemented. Marls occasionally contain smaller amount of siliciclastic component and pyrite occurrences. Open and reduced microfractures are sometimes visible. Sandstones are largely homogenous and thick to several meters. Horizontal and cross- lamination are detected only in uppermost part of the studied sedimentary succession (Lower Pontian deposits). Soft sediment deformation structures like load casts, ball-and-pillow and flame structures are relatively frequent. Rip- up marl clasts are sporadically observed suggesting channel sedimentation. Subvertical bioturbation is common. Terrigenous organic matter (phytoclast debris) are ubiquitous. Palynological macerals of the cored sedi-ments in the lower part of the investigated interval are rich in organic contents. Most of the palynofacies (70–80 %) is amorphous matter. Liptinite kerogene, generally made of weakly diverse dinocyst assemblage, some pollen grains (mostly bisaccate) and a few green algae remnants (Botryococcus brauni), completed the organic residue (10–20 %). Lignohumine clasts are scarce. Macerates are biodegraded. Pyrite inclusions in palynomorphs are frequent. Index fossils Spiniferites bentorii and S. bentorii oblongus specify the Upper Pannonian age. By the biostratigraphical classification of the organic walled microphytoplankton, samples belong to Spiniferites bentorii main zone, to the Spiniferites bentorii oblongus subzone. Younger sediments, although somewhat different, are also rich in organic matter. Lignohumine clasts of variable sorts and size make 30–60 %, while amorphous matter makes 30–40 % of total organic matter content. Liptinite component, composed of dinocysts, some freshwater alga (Pediastrum simplex, Spirogyra sp.), various polled grains (chiefly bisaccate) and a few spores, make 10–20 % of palynofacies. The Lower Pontian age is confirmed by Spiniferites balcanica, S. bentorii coniunctus and S. validus. According to the dinocyst palynozonation, samples belong to Spiniferites balcanica main zone, to the Spiniferites bentorii coniunctus subzone. Sediments originate in lacustrine environment as channel (and interchannel) deposits and subaquatic fans caused by gravity flow mechanisms (mostly turbidites). The Late Pannonian sedimentation took place in slightly deeper environment of decreased salinity, moderately distant to shore and terrigenous influx. The Early Pontian sediments were created in also somewhat distal and deeper freshwater environment but in the zone of the significant terrigenous influence.

Lake sedimentary record was used to reconstruct paleoenvironmental changes during Late Pleistocene and Holocene along the Croatian karst region on the Eastern Adriatic. Lake sediments were studied using multidisciplinary approach, combining sedimentological, mineralogical and geochemical analysis with paleontological proxies like pollen, ostracods or diatoms and dated using radiocarbon absolute dating. The most of the lakes cover the end of Pleistocene and beginning of the Holocene and show the evolution of the lakes and environmental changes during the last 12.000 years. Paleolimnological research was conducted on lake sediments on the eastern Adriatic coast (Lake Vrana on the Island Cres, Bokanjačko blato, Lake Vrana near Biograd and Lake Baćina- Crniševo) and they enabled reconstruction paleoenvironmental conditions from the late Pleistocene until present. Due to the proximity of the sea and permeable karst, the lake levels are influenced significantly by the sea level rise during the Holocene. Lakes represent typical karst lakes dominated by carbonate sedimentation, with periodic siliciclastic input. In every lake, three periods can be distinguished, the beginning of the Holocene with increased erosion and higher concentrations of siliciclastic material, middle Holocene with formation of deeper lakes and carbonate sedimentation, and Late Holocene characterised by erosion of siliciclastic material as a result of deforestation and human impact. Deposition of the siliciclastic material in Lake Vrana near Biograd lasted until 9.1 ka BP, when carbonate lake sedimentation started and the lake was formed. At the end of the period from 9.6 to 9.1 ka BP the dark organic rich sediment was deposited. The marine influence on the Lake Vrana sediments is evident after 6.1 ka BP. The present lake water conditions (alternating seasonal changes in the salinity, freshwater- brackish) were established at 3.8 ka BP. Deposition of homogenous carbonate mud (lake marl) started at 3 ka BP. In Lake Baćina deposition of the siliciclastic material was very intense from 11.7 to 10 ka BP, and then gradually decline until 7.5 ka BP. Dominant carbonate deposition lasted from 7.5 until 4.5 ka BP, when intensive changes in the sediments began, observed by the high sand fraction until 2.5 ka BP, and in between the alternate intervals were developed with calcite and quartz and those in which only calcite is present. In Bokanjačko blato the deposition of siliciclastic material lasted from 10.3 to 6.1 ka BP and then gradually decreases until 5.2 ka BP, when carbonate deposition began. In Lake Vrana on the Island Cres, the beginning of the Holocene is characterized by the deposition of the siliciclastic material, but which continues to the middle Holocene, until 4.5 ka BP when the carbonates appear. During the Holocene contrasting climate pattern has been identified in the central Mediterranean. Paleoenvironmental reconstructions of investigated lakes on the Eastern Adriatic coast correlate well with the lakes situated north of around 40°N of latitude, which are characterised by a wetter early Holocene, followed by relatively drier conditions during the middle Holocene and gradually increased moisture in the Late Holocene. South of 40°N of latitude there is opposite trend, very dry conditions in the first half of the Holocene and wettest period during the Mid Holocene followed by a progressive aridification, evident in lakes Preola and Pergusa on Sicily.

Analizirana je fosilna zajednica ostrakoda i palinomorfa iz sedimenata ispod i iznad sloja vulkanskog pepela na lokalitetu Sjeničak čija je starost određena na 16 Ma. Zajednica ostrakoda sugerira taloženje u relativno slonom vodenom tijelu, a zajednica palinomorfa subtropske klimatske uvijete.