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The Dinaridic segment of Neotethys was affected by a widespread shortening and related subduction-accretion-obduction processes that commenced in the middle Jurassic. In the Dinarides, the Krivaja-Konjuh Ophiolite Complex (KKOC) stands as the largest ophiolite complex with a well-exposed metamorphic sole which is the key to understanding the dynamics of intraoceanic subduction initiation in this part of Neotethys. In this contribution we present Sm-Nd geochronology on a granulite facies amphibolite from the KKOC, as well as a detailed petrological description. A five-point isochrone age calculated from clinopyroxene, plagioclase, garnet, amphibole and whole rock is 162 ± 14 Ma (MSWD = 6.2), whereas garnet and whole rock yield 160 ± 7 Ma. Ages calculated from all data points except clinopyroxene are 162 ± 5 Ma (MSWD = 1.09). Petrographic investigations suggest that these ages date granulite facies metamorphic conditions (i.e. peak metamorphism of Grt-Cpx amphibolite) rather than post-peak exhumation or obduction processes. Phase textural relationships are in line with previous research, which indicated a peak metamorphism equilibration pressure and temperature of ~1 GPa and ~800 °C, respectively. Granulite facies conditions are elucidated for an igneous precursor, which underwent a multi-stage metamorphism that gave rise to recrystallization of igneous clinopyroxene and plagioclase, epitaxial growth of amphibole, and garnet blastosis. Taking into account the age of gabbronorite from the youngest segment of the KKOC oceanic crust (Taorcian to Bathonian) and ages of radiolarian assemblages from the KKOC mélange (Bajocian to Bathonian), it may be inferred that within ~25 Ma the Dinaridic segment of Neotethys evolved rapidly from active ridge spreading through a stage of intraoceanic subduction and arc magmatism toward sub-ophioliteexhumation and further obduction along the Adria passive margin at the end of the Jurassic era.

The Dinaridic segment of Neotethys was affected by a widespread shortening and related subduction-accretion-obduction processes that commenced in the middle Jurassic. In the Dinarides, the Krivaja-Konjuh Ophiolite Complex (KKOC) stands as the largest ophiolite complex with a well-exposed metamorphic sole which is the key to understanding the dynamics of intraoceanic subduction initiation in this part of Neotethys. In this contribution we present Sm-Nd geochronology on a granulite facies amphibolite from the KKOC, as well as a detailed petrological description. A five-point isochrone age calculated from clinopyroxene, plagioclase, garnet, amphibole and whole rock is 162 ± 14 Ma (MSWD = 6.2), whereas garnet and whole rock yield 160 ± 7 Ma. Ages calculated from all data points except clinopyroxene are 162 ± 5 Ma (MSWD = 1.09). Petrographic investigations suggest that these ages date granulite facies metamorphic conditions (i.e. peak metamorphism of Grt-Cpx amphibolite) rather than post-peak exhumation or obduction processes. Phase textural relationships are in line with previous research, which indicated a peak metamorphism equilibration pressure and temperature of ~1 GPa and ~800 °C, respectively. Granulite facies conditions are elucidated for an igneous precursor, which underwent a multi-stage metamorphism that gave rise to recrystallization of igneous clinopyroxene and plagioclase, epitaxial growth of amphibole, and garnet blastosis. Taking into account the age of gabbronorite from the youngest segment of the KKOC oceanic crust (Taorcian to Bathonian) and ages of radiolarian assemblages from the KKOC mélange (Bajocian to Bathonian), it may be inferred that within ~25 Ma the Dinaridic segment of Neotethys evolved rapidly from active ridge spreading through a stage of intraoceanic subduction and arc magmatism toward sub-ophioliteexhumation and further obduction along the Adria passive margin at the end of the Jurassic era.

Ultramafic cumulate rocks represent the rarest allochthonous fragments of the Mesozoic oceanic lithosphere observed today in the Upper Jurassic to Lower Cretaceous mélange of Mt. Kalnik, located in the SW part of the Zagorje‒Mid-Transdanubian Zone (ZMTDZ). Poikilitic heteroadcumulate ultramafic rocks of Mt. Kalnik are represented by amphibole lherzolites/ harzburgite sand plagioclase lherzolites. Both were formed by in-situ processes within a magma chamber following the general crystallization sequence of: Al-chromite → Mg-rich olivine → enstatite ± augite→ Ca-amphibole (pargasite ± edenite ± magnesiohornblende) → Ca-plagioclase (An82.6-87.4). Cumulate minerals are spinel and olivine as well as orthopyroxene and clinopyroxene which areusually enclosed in intercumulate phases such as amphibole and/or plagioclase that render aninterstitial mesostasis. Rocks’ textural characteristics, mineral crystallization order and their phase chemistry are all suggestive of low-pressure sub-solidus crystallization in an open system. The low Ti content in augite and scant HFSE abundances suggest the studied rocks may have formed from a depleted mantle source. In addition to the medium to high degree of partial melting of the source, the parental process that gave rise to the Mt. Kalnik ultramafic cumulates also included a low degree of fractional crystallization. The segregation of oxidized Al-chromite and oikocrysts of pargasite and edenite in an early crystallization stage illustrates the formation of a cumulate sequence from volatile-rich magmas. These magmas usually have a high oxidation potential and are exclusively found in intra-oceanic subduction zones, predominantly in island arcs. The overall whole-rock geochemistry [e.g. (Nb/La)n = 0.25-0.34; (Ti/Gd)n = 0.49-0.89;(Th/Nb)n = 5.29-8.63; (La/Lu)cn = 0.57-0.68] together with a record of Ca-rich plagioclase (up toAn87.4) and low Ti clinopyroxene (≤0.54 wt%) corroborate the supra-subduction tholeiitic nature of the magma sou

Ultramafic cumulate rocks represent the rarest allochthonous fragments of the Mesozoic oceanic lithosphere observed today in the Upper Jurassic to Lower Cretaceous mélange of Mt. Kalnik, located in the SW part of the Zagorje‒Mid-Transdanubian Zone (ZMTDZ). Poikilitic heteroadcumulate ultramafic rocks of Mt. Kalnik are represented by amphibole lherzolites/ harzburgite sand plagioclase lherzolites. Both were formed by in-situ processes within a magma chamber following the general crystallization sequence of: Al-chromite → Mg-rich olivine → enstatite ± augite→ Ca-amphibole (pargasite ± edenite ± magnesiohornblende) → Ca-plagioclase (An82.6-87.4). Cumulate minerals are spinel and olivine as well as orthopyroxene and clinopyroxene which areusually enclosed in intercumulate phases such as amphibole and/or plagioclase that render aninterstitial mesostasis. Rocks’ textural characteristics, mineral crystallization order and their phase chemistry are all suggestive of low-pressure sub-solidus crystallization in an open system. The low Ti content in augite and scant HFSE abundances suggest the studied rocks may have formed from a depleted mantle source. In addition to the medium to high degree of partial melting of the source, the parental process that gave rise to the Mt. Kalnik ultramafic cumulates also included a low degree of fractional crystallization. The segregation of oxidized Al-chromite and oikocrysts of pargasite and edenite in an early crystallization stage illustrates the formation of a cumulate sequence from volatile-rich magmas. These magmas usually have a high oxidation potential and are exclusively found in intra-oceanic subduction zones, predominantly in island arcs. The overall whole-rock geochemistry [e.g. (Nb/La)n = 0.25-0.34; (Ti/Gd)n = 0.49-0.89;(Th/Nb)n = 5.29-8.63; (La/Lu)cn = 0.57-0.68] together with a record of Ca-rich plagioclase (up toAn87.4) and low Ti clinopyroxene (≤0.54 wt%) corroborate the supra-subduction tholeiitic nature of the magma sou

Mafic intrusive rocks are subordinately represented fragments of the oceanic crust in the ophiolite mélange exposedat Mts. Kalnik and Ivanščica located in the NW Dinaric-Vardar ophiolite zone. This ophiolite mélange occurs in thenorthern area of the Kalnik Unit and represents the SW surface boundary of the Zagorje-Mid-Transdanubian ShearZone. The mélange, except for mafic intrusive rocks, consists of a chaotic mixture of various extrusive rocks formedin different tectonic settings of the Repno Oceanic Domain (ROD). The ROD was the segment of Neo-Tethys thatconnects the Meliata-Maliak and Dinaric-Vardar oceanic systems. Previous study of mafic extrusive sequences suggestedan 80 Ma period of tectono-magmatic evolution of the ROD from intra-continental rifting during the Anisian,to the formation of proto-arc crust during the Callovian-Oxfordian. The domain exposes ophiolitic rocks in four mélangeareas. Isotropic gabbroic rocks that are abundant in two northern areas (Mts. Kalnik and Ivanščica), can be discriminatedinto three distinct geochemical groups: (A) N-MORB-type gabbro [(Th/Nb)n = 0.99–1.10; (Nb/La)n =0.95–0.99], (B) IAT-type amphibole gabbro with clear supra-subduction characteristics [(Th/Nb)n = 6.04–8.16; (Nb/La)n = 0.32–0.42] and (C) BABB-type amphibole-bearing gabbro [(Th/Nb)n = 2.88–4.02; (Nb/La)n = 0.58–0.69].Representative gabbro samples of each geochemical group were dated by the Ar-Ar and/or the K-Ar dating method.The Early Jurassic N-MORB-type gabbros (geochemical group A), ~185 Ma old, signifies a peculiar stage of Palaeo-Tethyan slab break-off. The Late Jurassic IAT-type gabbros (geochemical group B), ~147 Ma old, is the vestige of anascent intra-oceanic arc, whilst the Early Cretaceous BABB-type gabbros (geochemical group C), ~100 Ma old,provides evidence of magmatism in the back-arc marginal basin. The analyzed gabbroic rocks enable refinement andcompletion of the geodynamic evolution of the ROD, from the opening of an ensialic back-arc basin d

Mafic intrusive rocks are subordinately represented fragments of the oceanic crust in the ophiolite mélange exposedat Mts. Kalnik and Ivanščica located in the NW Dinaric-Vardar ophiolite zone. This ophiolite mélange occurs in thenorthern area of the Kalnik Unit and represents the SW surface boundary of the Zagorje-Mid-Transdanubian ShearZone. The mélange, except for mafic intrusive rocks, consists of a chaotic mixture of various extrusive rocks formedin different tectonic settings of the Repno Oceanic Domain (ROD). The ROD was the segment of Neo-Tethys thatconnects the Meliata-Maliak and Dinaric-Vardar oceanic systems. Previous study of mafic extrusive sequences suggestedan 80 Ma period of tectono-magmatic evolution of the ROD from intra-continental rifting during the Anisian,to the formation of proto-arc crust during the Callovian-Oxfordian. The domain exposes ophiolitic rocks in four mélangeareas. Isotropic gabbroic rocks that are abundant in two northern areas (Mts. Kalnik and Ivanščica), can be discriminatedinto three distinct geochemical groups: (A) N-MORB-type gabbro [(Th/Nb)n = 0.99–1.10; (Nb/La)n =0.95–0.99], (B) IAT-type amphibole gabbro with clear supra-subduction characteristics [(Th/Nb)n = 6.04–8.16; (Nb/La)n = 0.32–0.42] and (C) BABB-type amphibole-bearing gabbro [(Th/Nb)n = 2.88–4.02; (Nb/La)n = 0.58–0.69].Representative gabbro samples of each geochemical group were dated by the Ar-Ar and/or the K-Ar dating method.The Early Jurassic N-MORB-type gabbros (geochemical group A), ~185 Ma old, signifies a peculiar stage of Palaeo-Tethyan slab break-off. The Late Jurassic IAT-type gabbros (geochemical group B), ~147 Ma old, is the vestige of anascent intra-oceanic arc, whilst the Early Cretaceous BABB-type gabbros (geochemical group C), ~100 Ma old,provides evidence of magmatism in the back-arc marginal basin. The analyzed gabbroic rocks enable refinement andcompletion of the geodynamic evolution of the ROD, from the opening of an ensialic back-arc basin d

Uzorci djelomično ili potpuno izmijenjenih bazaltnih ekstruzivnih stijena iz ofiolitnog melanža Medvednice analizirani su primjenom optičke mikroskopije i rendgenske difrakcije u prahu. Kemijski sastav minerala u različitim paragenezama određen je pomoću elektronske mikrosonde, a strukture analiziranih mikrodomena su dokumentirane slikama unatrag raspršenih elektrona. Glavni alteracijski procesi uključuju albitizaciju, kloritizaciju, epidotizaciju, prehnitizaciju, pumpellyitizaciju, zeolitizaciju i titanitizaciju. Sporedni procesi su limonitizacija, kalcitizacija, zoisitizacija, sideritizacija, hematitizacija, manganizacija, piritizacija i silicifikacija koji nisu detaljno razmatrani. Albitizacija plagioklasa je dominantni alteracijski proces čije je postupno napredovanje jasno vidljivo na slikama unatrag raspršenih elektrona. Komponente izlužene alteracijom plagioklasa i klinopiroksena, moguće i uz komponente izlužene iz sekundarnih minerala prve generacije, omogućuju stvaranje klorita, epidota, pumpellyita i kalcita. U izvorno vitričnim uzorcima dio klorita i pumpellyita je nastao devitrifikacijom vulkanskog stakla. Alteracijom plagioklasa također nastaju i prehnit i laumontit. Obilato zastupljene nakupine leukoksena u svim uzorcima stijena predstavljaju guste agregate nanokristalnog titanita. Titan za stvaranje leukoksena potječe iz ilmenita odnosno titanom bogatog magnetita. Parageneze s epidotom bilježe komparativno najviši stupanj hidrotermalne alteracije koji odgovara srednjem odjeljku facijesa zelenih škriljavaca., The samples of partly or completely altered basaltic extrusive rocks from Mt. Medvednica ophiolite mélange were analysed by the optical microscopy and by X-ray powder diffraction (XRD). The chemical composition of minerals from different paragenetic assembleges were determinated by electron probe microanalysis (EPMA) and the measured microdomains were documented by back-scattered electrons (BSE) imagery. The most widespread alteration processes that affected analysed rocks are albitization, chloritization, epidotization, prehnitization, pumpellyitization, zeolitization and titanitization. Subordinate processes that include formation of limonite, calcite, zoisite, siderite, hematite, Mn-oxydes, pyrite and SiO2-phases were not constrained in this paper. Albitization is fairly dominant alteration process in all rock and its progradation throughout a plagioclase grain is clearly documented by BSE microphotographs and microprobe chemical analysis. Prehnite and laumontite are sporadic alteration products of plagioclases. The chemical components released during the alterations of plagioclases and/or clinopyroxenes along with components from circulating and percolating heated see water and fluids enable formation of chlorites, epidote and pumpellyite. Chlorites and pumpellyite formed also by devitrification of volcanic glass in vitric rim of pillow lavas. Small patches of leucoxene, that is abundant in all samples, represent dense aggregates of titanite nanocrystals replacing ilmenite and/or Ti-magnetite. Epidote-bearing paragenesis in the analyzed rocks record comparatively the highest alterations grade that correspond to the middle grade of greenschist facies metamorphism typical of upper sequence of a see floor crust.

The petrographic composition and transport direction of medium and coarse-grained clastic material of Dilj gora Mt. which is located in the south Pannonian basin, show that this area experienced several changes in provenance of arriving detritus through the Neogene. Detritus for the oldest Lower Miocene (Ravan unit) was transported generally from the south and most probably derived from clastic and carbonate sediments and metamorphic rocks of the Internal Dinarides. Detritus of the Lower Miocene–Middle Miocene (Tuk unit) was originated by weathering of acid magmatic and metamorphic rocks with significant input of materials from local sources, primarily from the Internal Dinarides and from Požeška gora and Dilj gora Mts. During the entire Middle Miocene (Zdenci, Dubovik and Glogovica units) and through the older part of the Late Miocene (Croatica and Pavlovci unit) the deposition of siliciclastic gravel and sandy detritus was less significant. Only the Middle Miocene deposits (Kasonja unit) contain clastic detritus derived from granitoids, metamorphic and sedimentary rocks of the hinterland. The source area of this detritus was most probably in the Slavonian Mts. (Papuk, Psunj, Požeška gora Mt.) or the mountains of northern Bosnia (Motajica Mt.). At the time of late Upper Miocene (Andraševec and Nova Gradiška units) detritus derived from different metamorphic and older sedimentary rocks. The structural and mineralogical maturity of these sediments and their transport directions indicates an Alpine-Carpathian provenance of material. Most of the detritus of the Pliocene sediments (Cernik unit) also belong to an Alpine-Carpathian provenance, however a small part of it is of local origin and came from uplifted and mainly sedimentary rocks.Determinated various textural characteristics and diverse modal compositions and provenance of Neogene clastic material of Dilj gora Mt. can be attributed to differing source rock compositions and locations of source areas, b

A novel approach, designated as the particle-mediated, nano-scale, aggregation route, to the formation and growth of spherical and colloid-sized anhydrous carbonate mineral particles and hierarchically organized biomineral carbonate structures is discussed. This model is inconsistent with the conventional crystallization mechanism, which is primarily based on diffusion growth. It is determined by the initial formation of nanosized, crystalline particles, (singlets), and their subsequent aggregation into submicrometre and micron-sized carbonate particle assemblies. This concept is much more common in Nature than has previously been assumed. The number of new examples of its significance in the formation of inorganic and biogenic carbonate mineral solids has significantly increased in recent years. A few illustrations are presented to show the appearance of nanostructured and hierarchically organized carbonate particles formed through the nano-scale aggregation route in natural systems, together with those obtained from laboratory model experiments.

The petrographic composition and transport direction of medium and coarse-grained clastic material of Dilj gora Mt. which is located in the south Pannonian basin, show that this area experienced several changes in provenance of arriving detritus through the Neogene. Detritus for the oldest Lower Miocene (Ravan unit) was transported generally from the south and most probably derived from clastic and carbonate sediments and metamorphic rocks of the Internal Dinarides. Detritus of the Lower Miocene–Middle Miocene (Tuk unit) was originated by weathering of acid magmatic and metamorphic rocks with significant input of materials from local sources, primarily from the Internal Dinarides and from Požeška gora and Dilj gora Mts. During the entire Middle Miocene (Zdenci, Dubovik and Glogovica units) and through the older part of the Late Miocene (Croatica and Pavlovci unit) the deposition of siliciclastic gravel and sandy detritus was less significant. Only the Middle Miocene deposits (Kasonja unit) contain clastic detritus derived from granitoids, metamorphic and sedimentary rocks of the hinterland. The source area of this detritus was most probably in the Slavonian Mts. (Papuk, Psunj, Požeška gora Mt.) or the mountains of northern Bosnia (Motajica Mt.). At the time of late Upper Miocene (Andraševec and Nova Gradiška units) detritus derived from different metamorphic and older sedimentary rocks. The structural and mineralogical maturity of these sediments and their transport directions indicates an Alpine-Carpathian provenance of material. Most of the detritus of the Pliocene sediments (Cernik unit) also belong to an Alpine-Carpathian provenance, however a small part of it is of local origin and came from uplifted and mainly sedimentary rocks.Determinated various textural characteristics and diverse modal compositions and provenance of Neogene clastic material of Dilj gora Mt. can be attributed to differing source rock compositions and locations of source areas, b

A novel approach, designated as the particle-mediated, nano-scale, aggregation route, to the formation and growth of spherical and colloid-sized anhydrous carbonate mineral particles and hierarchically organized biomineral carbonate structures is discussed. This model is inconsistent with the conventional crystallization mechanism, which is primarily based on diffusion growth. It is determined by the initial formation of nanosized, crystalline particles, (singlets), and their subsequent aggregation into submicrometre and micron-sized carbonate particle assemblies. This concept is much more common in Nature than has previously been assumed. The number of new examples of its significance in the formation of inorganic and biogenic carbonate mineral solids has significantly increased in recent years. A few illustrations are presented to show the appearance of nanostructured and hierarchically organized carbonate particles formed through the nano-scale aggregation route in natural systems, together with those obtained from laboratory model experiments.