PETROLOŠKE KARAKTERISTIKE KLASTIČNIH TALOŽNIH STIJENA IZ RUDNIKA SVETA BARBARA U RUDAMA KRAJ SAMOBORA

In the scope of this research, the petrographic and geochemical analyses of clastic sedimentary rocks from the St. Barbara, copper and iron ore mine in Rude near Samobor, have been made, aiming to classify and determine the provenance and environment of formation of clastic sedimentary rocks, as well as the influence of hydrothermal fluids on their properties. Eight samples were collected in total from different locations in the mine. Six of those samples have been studied in detail. The results showed structural and geochemical variability and uneven hydrothermal alteration intensity in the samples. Based on petrographic analyses, three rocks are classified as sublithoarenite, quartz arenite and quartz greywacke. Three of the samples are classified as ore breccia, ore sandstone, and ore silt-sandstone due to the pronounced hydrothermal alterations and ore mineralisation. Comprehensively, petrographic and geochemical analyses indicate that the source rocks of the investigated clastic sedimentary rocks were felsic (La/Sc = 0.9-6.2; Th/Sc = 1.3-2.4), most probably sedimentary, possibly resedimented rocks. The extent of source rock weathering was very high (Chemical Index of Alteration CIA = 52.1 - 81.3 %) and the geotectonic position of the sedimentary basin was very likely to be at the passive continental margin.U okviru ovoga istraživanja napravljene su petrografske i geokemijske analize klastičnih taložnih stijena iz rudnika bakra i željeza Sveta Barbara u Rudama kraj Samobora s ciljem da se klasificira i odredi podrijetlo sedimenata, kao i okolina formiranja klastičnih taložnih stijena te utjecaj hidrotermalnih fluida na njihova svojstva. Ukupno je prikupljeno osam uzoraka s različitih lokaliteta unutar rudnika, od čega je šest uzoraka detaljno analizirano. Rezultati su pokazali strukturnu i geokemijsku varijabilnost i nejednak intenzitet hidrotermalne alteracije u uzorcima. Na temelju petrografske analize tri stijene klasificirane su kao sublitoarenit, kvarcni arenit i kvarcna grauvaka. Tri uzorka klasificirana su kao orudnjena breča, orudnjeni pješčenjak i orudnjeni siltozni pješčenjak zbog izrazite hidrotermalne alteracije i rudne mineralizacije. Petrografske i geokemijske analize pokazuju da su ishodišne stijene istraživanih klastičnih sedimenata bile felzične (La/Sc = 0,9 – 6,2; Th/Sc = 1,3 – 2,4), najvjerojatnije taložne, i moguće pretaložene. Stupanj trošenja ishodišnih stijena bio je vrlo visok (kemijski indeks alteracije – CIA = 52,1 – 81,3 %), a geotektonska pozicija sedimentnoga bazena vrlo je vjerojatno bila na pasivnome kontinentalnom rubu

ARCHAEOLOGICAL RESEARCH ON THE LOCALITY OF NOVA COLOR IN SPLIT

Zbog planirane izgradnje poslovno-stambenog kompleksa u Ulici Ljudevita Posavskog u Splitu obavljena su arheološka sondažna istraživanja kojima je utvrđeno da je parcela intenzivno korištena i izgrađivana. Pokretni arheološki nalazi datiraju se od prapovijesti, preko antike i srednjeg vijeka do danas. Pronađeni antički grob svjedoči o postojanju antičke nekropole.A residential-business complex with accompanying garages was planned to be constructed in Split, in Ljudevita Posavskog street. Prior to construction, it was proved necessary to demolish the old Nova Color factory building, and, then, to carry out the archaeological probe-research. The overall number of seven probes, (S1-S7), together with two trenches, (R1-R2) were excavated at the site. The probe 2 identified a late antique grave under tegulae that were arranged in the east-west direction. Tegulae were arranged in the form of the roof consisting of two surfaces. Four tegulae were laid flat on lateral sides and three imbrices were laid over their joints. On the top of the grave, a tegula was vertically laid. Another tegula found on the west portion of the grave, was laid directly onto the legs of the skeleton, whereas all other tegulae were laid onto the surface of the ground in which the skeleton was buried. The stretched palms of the hands were positioned below the pelvis and placed on fragmented tegula. The rest of the skeleton was laid directly onto the ground. It was revealed by the well-preserved bones that the skeleton belonged to a relatively young male. None of the other findings were revealed at the site. This particular grave is said to be a remnant of a large necropolis that surrounded two early-Christian basilicas. Their remnants are preserved in close proximity of a building site where similar graves were once found. The remnants of necropolis at this particular site were destroyed during construction works in the past. The north portion of the probe 2 revealed a preserved construction containing two massive walls and an array of canals between them. These canals currently function as precipitation and fecal sewage system. The construction is situated on the entire surface of the 48 square metre site, in the east-west direction. The construction continues to the east into the yard of a neighbouring building, whereas the walls at its west corner twist: one twists towards the south-west, and another towards north-east to be connected with another fragmented wall that continues all the way towards the outer borders of the site. The north and south surfaces of the wall have been cleaned and the orthophoto procedure has been carried out. Orthophoto revealed stitches along the wall. The lower part of the south wall is made of irregularly shaped stones, that were covered with plaster. Its upper part was, however, made of smaller stones. This specific and different construction of the two walls indicates different phases of their making. Rectangular openings, that descend towards the canals, are visible on both walls. The south wall is 70 centimetres wide and the north one is 80 centimetres wide. The aforementioned construction lost its original function when its adjacent west walls were built: since then it has been used as precipitation and fecal sewage system. A small part of a previously devastated room containing a wood stove and a toilet bowl was also revealed next to the north wall. The research brought yet another fact to light: repeated construction works in the past resulted in the devastation of the entire locality. The locality is double-layered, its cultural layer being devastated to a large extent. A large number of archaeological findings were revealed in the so-called light brown layer and between the light brown and red layer. A considerably smaller number of findings were revealed in the red layer. The disordered findings in the light brown layer are dated to several periods of human history. The most significant findings include fragments of glazed pottery, created in the period between the end of the 14th, the early 15th and 18th century. The significant findings also include the fragments of the antique and late antique pottery. The most predominant types of glazed pottery revealed at the site are the so-called maiolica pottery dating from the period between the 15th and early 18th century, and the fragments of the late antique sgraffito pottery, dating from the 16th and 17th century. The archaic sgraffito pottery from the period between the late 14th and early 15th century was also revealed by the research as well as some fragments of rough and painted pottery from the 15th and 16th century. The majority of revealed pottery includes the fragments of amphora and kitchenware handles, brims, walls and linings. Some fragments of glass containers were also revealed by the research. Certainly, the most prominent among them are the fragments of the so-called krautstrunkt-type glasses, that were revealed in the probes 1 and 3, a well-preserved glass lid and a fragment of a bracelet that was made of glass paste. A large number of preserved and fragmented bronze objects were revealed, such as the fragments of needles, rings, little buckles, and some late antique bronze coins. The research also revealed a significant number of retouched flint tools, such as knives, scrapers and two gunflints

Petrogenesis of peridotites and pyroxenites in the area of Banovina, Croatia : doctoral dissertation

U ovom radu istraženi su peridotiti i pirokseniti na području Banovine. Ove stijene su formirane kao dijelovi nekadašnjeg Zemljinog plašta te predstavljaju baznu jedinicu ofiolita i dokaz su postojanja oceanskog prostora, a izdignuti su u gornje dijelove kore intenzivnim tektonskim pokretima koji su se počeli odvijati za vrijeme jure, prije oko 150 milijuna godina. Peridotiti i pirokseniti Banovine dio su Centralnog dinaridskog ofiolitnog pojasa (CDOB = „Central Dinaridic Ophiolite Belt“) koji se proteže od Banovine prema jugoistoku preko Bosne i Hercegovine u Srbiju. Ovaj pojas ukazuje na nekadašnji oceanski prostor Neotethysa, a rekonstrukcija geodinamskog razvoja takvog prostora unutar šire regionalne slike vrlo je kompleksna. Napravljena su detaljna terenska istraživanja te petrografske i geokemijske analize peridotita i piroksenita. Utvrđeno je da se na prostoru Banovine po strukturnim i kemijskim značajkama razlikuju dvije vrste peridotita koje i geografski pripadaju različitim lokalitetima te se mogu svrstati u dva pojasa, sjeverni i južni. Unutar sjevernog pojasa (S-pojas) prevladavaju serpentinitne breče i serpentinizirani spinelski lercoliti, koji se na terenu prepoznaju po strukturama karakterističnim za ofiolitni melanž. Geokemijske karakteristike peridotita S-pojasa ukazuju na porijeklo iz suboceanskog plašta koji je prolazio kroz procese taljenja na području srednje oceanskih hrptova, zbog čega su klasificirani kao ofiolitni peridotiti. Južni pojas (J-pojas) sadrži spinelske lercolite, dunite i piroksenite koji se izmjenjuju unutar prostorno vrlo ograničenih prostora. Geokemijske karakteristike peridotita J-pojasa ukazuju na subkontinentalno porijeklo te su najvjerojatnije formirane tijekom faze početnog rifta gdje su se kao dijelovi kontinentalnog plašta izdizali u gornje dijelove kore, tijekom čega su prošli kroz vrlo nizak stupanj taljenja. Zbog navedenih značajki peridotiti J-pojasa klasificirani su kao orogeni peridotiti. Pirokseniti koji se nalaze unutar J-pojasa pokazuju drugačije petrografske i geokemijske karakteristike od peridotita. Oni su najvjerojatnije nastali kao zasebna parageneza kristalizacijom iz taljevina zasad nepoznatog porijekla koje su se probijale kroz plašt. Zaključno, ovaj rad je pokazao kako peridotiti i pirokseniti Banovine, a samim time i CDOB-a nose zapis triju različitih faza evolucije oceanskog prostora Neotethysa: a) rane faze početnog rifta i otvaranja oceana (peridotiti i moguće pirokseniti J-pojasa); b) kasnije faze već razvijenog oceanskog prostora (peridotiti S-pojasa) i c) faze zatvaranja oceana koja je evidentna iz struktura tipičnih za ofiolitni melanž, ali i prisutnosti amfibolita koji se nalaze u kontaktu s peridotitima, a koji su nastali kao posljedica obdukcije.In this paper, peridotites and pyroxenites in the Banovina area were investigated. These rocks were formed as parts of the former Earth's mantle and represent the base unit of ophiolites which indicates the existence of the ocean. They were ascended to the upper crust by intense tectonic processes that began about 150 million years ago. The peridotites and pyroxenites of the Banovina are part of the Central Dinaridic Ophiolite Belt (CDOB) that extends from the Banovina to the southeast through Bosnia and Herzegovina to Serbia. This belt indicates the former oceanic space, and the reconstruction of the development of such space within the wider regional picture is very complex. In this paper, detailed field research and petrographic and geochemical analyzes of peridotite and pyroxenite were performed. Field research has shown that ultramafics in the Banovina appear in two geographically different belts, the northern (S-belt) and the southern (J-belt). The S-belt contains mostly serpentinite breccias and serpentinized lherzolites. The J-belt contains larger masses of peridotites which consist predominantly of spinel lherzolites, and subordinate dunites and pyroxenites. Petrographic analyzes showed that spinel lherzolites and pyroxenites from Jbelt are significantly richer in clinopyroxene than spinel lherzolites from S-belt. In addition, petrographic analyzes showed large differences in the rock textures of the S- and J-belts. Within the S-belt, protogranular to porphyroblastic structures predominate, while within the J-belt, equigranular to porphyroclastic structures predominate. Pyroxenite structures show distinctly porphyroclastic structures. Chemical analyzes have shown that Jband spinel lherzolites have a higher content of Al2O3, CaO, Na2O, REE, and other trace elements than S-belt spinel lherzolites. J-belt pyroxenites have extremely high amounts of these elements, while J-belt dunites have a lower content of same elements, but higher amount of MgO. oxides of the main elements and a very low content of REE and trace elements. Analyzes of the major elements in all minerals show a higher Mg-number in spinel lherzolites from the S-belt. Clinopyroxenes and orthopyroxenes of all J-belt ultramafics generally have a higher content of Al2O3, Na2O, REE, and trace elements. The Cr2O3 content is higher in clinopyroxenes and orthopyroxenes from the S-belt and dunites from the J-belt than in spinel lherzolites from the J-belt. Both pyroxenes show zonal structure. In clinopyroxene, the content of SiO2, CaO, and TiO2 increases in the rim direction, and Al2O3, FeO, and Na2O increase in the core direction. In orthopyroxene, the content of SiO2, MgO, and FeO increases from the core to the rim, and the content of Al2O3 and CaO in the same direction decreases. Analyzes of the oxides of the main elements in spinel showed that S-belt spinel lherzolites have a significantly higher Cr2O3 content, while spinels from spinel lherzolites and pyroxenites from the J-belt have a significantly higher Al2O3 content. Part of the spinels of S-belt spinel lherzolites shows a pronounced zonation with Cr2O3 enrichment towards the rims, which is a consequence of the secondary alteration and formation of garnet along the edges of the spinel. Isotopic analyzes gave significantly higher εNd and 87Sr/86Sr values in S-belt spinel lherzolite compared to those in J-belt pyroxenite. The geochemical characteristics of S-belt peridotites indicate their origin from a suboceanic mantle, more than 70 km deep, which underwent melting processes (up to 15% partial melting) in the area of mid-ocean ridges and are classified as ophiolitic peridotites. The southern belt (J-belt) contains spinel lherzolites, dunites, and pyroxenites that alternate within very limited space. The geochemical characteristics of the J-belt peridotites indicate a subcontinental origin and were most likely formed during the initial rifting phase where they ascended as parts of the continental mantle to the upper crust, during which they went through a very small degree of melting (up to 5% partial melting). Peridotites from the J-belt are classified as orogenic peridotites. Pyroxenites, which are located within the J-belt, show different petrographic and geochemical characteristics and were most likely formed as a separate paragenesis by crystallization from melts of unknown but possibly already depleted source. Dunites show different geochemical characteristics and may have been formed by different geological multiple processes. The diverse lithology of ultramafics (spinel lherzolites, dunites, and pyroxenites) in the limited space of the J-belt indicates the very heterogeneous nature of the subcontinental mantle. In conclusion, this paper showed how the peridotites and pyroxenites of the Banovina, and thus the CDOBs, record three different phases of ocean evolution, the early phase of the initial rift and opening of the ocean (J-belt peridotites and pyroxenites), later phase of the already developed ocean (S-belt peridotites), and also the phase of ocean closure which is evident from the structures of melánge, but also from the presence of amphibolite contact formed as a result of obduction

Petrogenesis of peridotites and pyroxenites in the area of Banovina, Croatia : doctoral dissertation

U ovom radu istraženi su peridotiti i pirokseniti na području Banovine. Ove stijene su formirane kao dijelovi nekadašnjeg Zemljinog plašta te predstavljaju baznu jedinicu ofiolita i dokaz su postojanja oceanskog prostora, a izdignuti su u gornje dijelove kore intenzivnim tektonskim pokretima koji su se počeli odvijati za vrijeme jure, prije oko 150 milijuna godina. Peridotiti i pirokseniti Banovine dio su Centralnog dinaridskog ofiolitnog pojasa (CDOB = „Central Dinaridic Ophiolite Belt“) koji se proteže od Banovine prema jugoistoku preko Bosne i Hercegovine u Srbiju. Ovaj pojas ukazuje na nekadašnji oceanski prostor Neotethysa, a rekonstrukcija geodinamskog razvoja takvog prostora unutar šire regionalne slike vrlo je kompleksna. Napravljena su detaljna terenska istraživanja te petrografske i geokemijske analize peridotita i piroksenita. Utvrđeno je da se na prostoru Banovine po strukturnim i kemijskim značajkama razlikuju dvije vrste peridotita koje i geografski pripadaju različitim lokalitetima te se mogu svrstati u dva pojasa, sjeverni i južni. Unutar sjevernog pojasa (S-pojas) prevladavaju serpentinitne breče i serpentinizirani spinelski lercoliti, koji se na terenu prepoznaju po strukturama karakterističnim za ofiolitni melanž. Geokemijske karakteristike peridotita S-pojasa ukazuju na porijeklo iz suboceanskog plašta koji je prolazio kroz procese taljenja na području srednje oceanskih hrptova, zbog čega su klasificirani kao ofiolitni peridotiti. Južni pojas (J-pojas) sadrži spinelske lercolite, dunite i piroksenite koji se izmjenjuju unutar prostorno vrlo ograničenih prostora. Geokemijske karakteristike peridotita J-pojasa ukazuju na subkontinentalno porijeklo te su najvjerojatnije formirane tijekom faze početnog rifta gdje su se kao dijelovi kontinentalnog plašta izdizali u gornje dijelove kore, tijekom čega su prošli kroz vrlo nizak stupanj taljenja. Zbog navedenih značajki peridotiti J-pojasa klasificirani su kao orogeni peridotiti. Pirokseniti koji se nalaze unutar J-pojasa pokazuju drugačije petrografske i geokemijske karakteristike od peridotita. Oni su najvjerojatnije nastali kao zasebna parageneza kristalizacijom iz taljevina zasad nepoznatog porijekla koje su se probijale kroz plašt. Zaključno, ovaj rad je pokazao kako peridotiti i pirokseniti Banovine, a samim time i CDOB-a nose zapis triju različitih faza evolucije oceanskog prostora Neotethysa: a) rane faze početnog rifta i otvaranja oceana (peridotiti i moguće pirokseniti J-pojasa); b) kasnije faze već razvijenog oceanskog prostora (peridotiti S-pojasa) i c) faze zatvaranja oceana koja je evidentna iz struktura tipičnih za ofiolitni melanž, ali i prisutnosti amfibolita koji se nalaze u kontaktu s peridotitima, a koji su nastali kao posljedica obdukcije.In this paper, peridotites and pyroxenites in the Banovina area were investigated. These rocks were formed as parts of the former Earth's mantle and represent the base unit of ophiolites which indicates the existence of the ocean. They were ascended to the upper crust by intense tectonic processes that began about 150 million years ago. The peridotites and pyroxenites of the Banovina are part of the Central Dinaridic Ophiolite Belt (CDOB) that extends from the Banovina to the southeast through Bosnia and Herzegovina to Serbia. This belt indicates the former oceanic space, and the reconstruction of the development of such space within the wider regional picture is very complex. In this paper, detailed field research and petrographic and geochemical analyzes of peridotite and pyroxenite were performed. Field research has shown that ultramafics in the Banovina appear in two geographically different belts, the northern (S-belt) and the southern (J-belt). The S-belt contains mostly serpentinite breccias and serpentinized lherzolites. The J-belt contains larger masses of peridotites which consist predominantly of spinel lherzolites, and subordinate dunites and pyroxenites. Petrographic analyzes showed that spinel lherzolites and pyroxenites from Jbelt are significantly richer in clinopyroxene than spinel lherzolites from S-belt. In addition, petrographic analyzes showed large differences in the rock textures of the S- and J-belts. Within the S-belt, protogranular to porphyroblastic structures predominate, while within the J-belt, equigranular to porphyroclastic structures predominate. Pyroxenite structures show distinctly porphyroclastic structures. Chemical analyzes have shown that Jband spinel lherzolites have a higher content of Al2O3, CaO, Na2O, REE, and other trace elements than S-belt spinel lherzolites. J-belt pyroxenites have extremely high amounts of these elements, while J-belt dunites have a lower content of same elements, but higher amount of MgO. oxides of the main elements and a very low content of REE and trace elements. Analyzes of the major elements in all minerals show a higher Mg-number in spinel lherzolites from the S-belt. Clinopyroxenes and orthopyroxenes of all J-belt ultramafics generally have a higher content of Al2O3, Na2O, REE, and trace elements. The Cr2O3 content is higher in clinopyroxenes and orthopyroxenes from the S-belt and dunites from the J-belt than in spinel lherzolites from the J-belt. Both pyroxenes show zonal structure. In clinopyroxene, the content of SiO2, CaO, and TiO2 increases in the rim direction, and Al2O3, FeO, and Na2O increase in the core direction. In orthopyroxene, the content of SiO2, MgO, and FeO increases from the core to the rim, and the content of Al2O3 and CaO in the same direction decreases. Analyzes of the oxides of the main elements in spinel showed that S-belt spinel lherzolites have a significantly higher Cr2O3 content, while spinels from spinel lherzolites and pyroxenites from the J-belt have a significantly higher Al2O3 content. Part of the spinels of S-belt spinel lherzolites shows a pronounced zonation with Cr2O3 enrichment towards the rims, which is a consequence of the secondary alteration and formation of garnet along the edges of the spinel. Isotopic analyzes gave significantly higher εNd and 87Sr/86Sr values in S-belt spinel lherzolite compared to those in J-belt pyroxenite. The geochemical characteristics of S-belt peridotites indicate their origin from a suboceanic mantle, more than 70 km deep, which underwent melting processes (up to 15% partial melting) in the area of mid-ocean ridges and are classified as ophiolitic peridotites. The southern belt (J-belt) contains spinel lherzolites, dunites, and pyroxenites that alternate within very limited space. The geochemical characteristics of the J-belt peridotites indicate a subcontinental origin and were most likely formed during the initial rifting phase where they ascended as parts of the continental mantle to the upper crust, during which they went through a very small degree of melting (up to 5% partial melting). Peridotites from the J-belt are classified as orogenic peridotites. Pyroxenites, which are located within the J-belt, show different petrographic and geochemical characteristics and were most likely formed as a separate paragenesis by crystallization from melts of unknown but possibly already depleted source. Dunites show different geochemical characteristics and may have been formed by different geological multiple processes. The diverse lithology of ultramafics (spinel lherzolites, dunites, and pyroxenites) in the limited space of the J-belt indicates the very heterogeneous nature of the subcontinental mantle. In conclusion, this paper showed how the peridotites and pyroxenites of the Banovina, and thus the CDOBs, record three different phases of ocean evolution, the early phase of the initial rift and opening of the ocean (J-belt peridotites and pyroxenites), later phase of the already developed ocean (S-belt peridotites), and also the phase of ocean closure which is evident from the structures of melánge, but also from the presence of amphibolite contact formed as a result of obduction

Petrogenesis of peridotites and pyroxenites in the area of Banovina, Croatia : doctoral dissertation

U ovom radu istraženi su peridotiti i pirokseniti na području Banovine. Ove stijene su formirane kao dijelovi nekadašnjeg Zemljinog plašta te predstavljaju baznu jedinicu ofiolita i dokaz su postojanja oceanskog prostora, a izdignuti su u gornje dijelove kore intenzivnim tektonskim pokretima koji su se počeli odvijati za vrijeme jure, prije oko 150 milijuna godina. Peridotiti i pirokseniti Banovine dio su Centralnog dinaridskog ofiolitnog pojasa (CDOB = „Central Dinaridic Ophiolite Belt“) koji se proteže od Banovine prema jugoistoku preko Bosne i Hercegovine u Srbiju. Ovaj pojas ukazuje na nekadašnji oceanski prostor Neotethysa, a rekonstrukcija geodinamskog razvoja takvog prostora unutar šire regionalne slike vrlo je kompleksna. Napravljena su detaljna terenska istraživanja te petrografske i geokemijske analize peridotita i piroksenita. Utvrđeno je da se na prostoru Banovine po strukturnim i kemijskim značajkama razlikuju dvije vrste peridotita koje i geografski pripadaju različitim lokalitetima te se mogu svrstati u dva pojasa, sjeverni i južni. Unutar sjevernog pojasa (S-pojas) prevladavaju serpentinitne breče i serpentinizirani spinelski lercoliti, koji se na terenu prepoznaju po strukturama karakterističnim za ofiolitni melanž. Geokemijske karakteristike peridotita S-pojasa ukazuju na porijeklo iz suboceanskog plašta koji je prolazio kroz procese taljenja na području srednje oceanskih hrptova, zbog čega su klasificirani kao ofiolitni peridotiti. Južni pojas (J-pojas) sadrži spinelske lercolite, dunite i piroksenite koji se izmjenjuju unutar prostorno vrlo ograničenih prostora. Geokemijske karakteristike peridotita J-pojasa ukazuju na subkontinentalno porijeklo te su najvjerojatnije formirane tijekom faze početnog rifta gdje su se kao dijelovi kontinentalnog plašta izdizali u gornje dijelove kore, tijekom čega su prošli kroz vrlo nizak stupanj taljenja. Zbog navedenih značajki peridotiti J-pojasa klasificirani su kao orogeni peridotiti. Pirokseniti koji se nalaze unutar J-pojasa pokazuju drugačije petrografske i geokemijske karakteristike od peridotita. Oni su najvjerojatnije nastali kao zasebna parageneza kristalizacijom iz taljevina zasad nepoznatog porijekla koje su se probijale kroz plašt. Zaključno, ovaj rad je pokazao kako peridotiti i pirokseniti Banovine, a samim time i CDOB-a nose zapis triju različitih faza evolucije oceanskog prostora Neotethysa: a) rane faze početnog rifta i otvaranja oceana (peridotiti i moguće pirokseniti J-pojasa); b) kasnije faze već razvijenog oceanskog prostora (peridotiti S-pojasa) i c) faze zatvaranja oceana koja je evidentna iz struktura tipičnih za ofiolitni melanž, ali i prisutnosti amfibolita koji se nalaze u kontaktu s peridotitima, a koji su nastali kao posljedica obdukcije.In this paper, peridotites and pyroxenites in the Banovina area were investigated. These rocks were formed as parts of the former Earth's mantle and represent the base unit of ophiolites which indicates the existence of the ocean. They were ascended to the upper crust by intense tectonic processes that began about 150 million years ago. The peridotites and pyroxenites of the Banovina are part of the Central Dinaridic Ophiolite Belt (CDOB) that extends from the Banovina to the southeast through Bosnia and Herzegovina to Serbia. This belt indicates the former oceanic space, and the reconstruction of the development of such space within the wider regional picture is very complex. In this paper, detailed field research and petrographic and geochemical analyzes of peridotite and pyroxenite were performed. Field research has shown that ultramafics in the Banovina appear in two geographically different belts, the northern (S-belt) and the southern (J-belt). The S-belt contains mostly serpentinite breccias and serpentinized lherzolites. The J-belt contains larger masses of peridotites which consist predominantly of spinel lherzolites, and subordinate dunites and pyroxenites. Petrographic analyzes showed that spinel lherzolites and pyroxenites from Jbelt are significantly richer in clinopyroxene than spinel lherzolites from S-belt. In addition, petrographic analyzes showed large differences in the rock textures of the S- and J-belts. Within the S-belt, protogranular to porphyroblastic structures predominate, while within the J-belt, equigranular to porphyroclastic structures predominate. Pyroxenite structures show distinctly porphyroclastic structures. Chemical analyzes have shown that Jband spinel lherzolites have a higher content of Al2O3, CaO, Na2O, REE, and other trace elements than S-belt spinel lherzolites. J-belt pyroxenites have extremely high amounts of these elements, while J-belt dunites have a lower content of same elements, but higher amount of MgO. oxides of the main elements and a very low content of REE and trace elements. Analyzes of the major elements in all minerals show a higher Mg-number in spinel lherzolites from the S-belt. Clinopyroxenes and orthopyroxenes of all J-belt ultramafics generally have a higher content of Al2O3, Na2O, REE, and trace elements. The Cr2O3 content is higher in clinopyroxenes and orthopyroxenes from the S-belt and dunites from the J-belt than in spinel lherzolites from the J-belt. Both pyroxenes show zonal structure. In clinopyroxene, the content of SiO2, CaO, and TiO2 increases in the rim direction, and Al2O3, FeO, and Na2O increase in the core direction. In orthopyroxene, the content of SiO2, MgO, and FeO increases from the core to the rim, and the content of Al2O3 and CaO in the same direction decreases. Analyzes of the oxides of the main elements in spinel showed that S-belt spinel lherzolites have a significantly higher Cr2O3 content, while spinels from spinel lherzolites and pyroxenites from the J-belt have a significantly higher Al2O3 content. Part of the spinels of S-belt spinel lherzolites shows a pronounced zonation with Cr2O3 enrichment towards the rims, which is a consequence of the secondary alteration and formation of garnet along the edges of the spinel. Isotopic analyzes gave significantly higher εNd and 87Sr/86Sr values in S-belt spinel lherzolite compared to those in J-belt pyroxenite. The geochemical characteristics of S-belt peridotites indicate their origin from a suboceanic mantle, more than 70 km deep, which underwent melting processes (up to 15% partial melting) in the area of mid-ocean ridges and are classified as ophiolitic peridotites. The southern belt (J-belt) contains spinel lherzolites, dunites, and pyroxenites that alternate within very limited space. The geochemical characteristics of the J-belt peridotites indicate a subcontinental origin and were most likely formed during the initial rifting phase where they ascended as parts of the continental mantle to the upper crust, during which they went through a very small degree of melting (up to 5% partial melting). Peridotites from the J-belt are classified as orogenic peridotites. Pyroxenites, which are located within the J-belt, show different petrographic and geochemical characteristics and were most likely formed as a separate paragenesis by crystallization from melts of unknown but possibly already depleted source. Dunites show different geochemical characteristics and may have been formed by different geological multiple processes. The diverse lithology of ultramafics (spinel lherzolites, dunites, and pyroxenites) in the limited space of the J-belt indicates the very heterogeneous nature of the subcontinental mantle. In conclusion, this paper showed how the peridotites and pyroxenites of the Banovina, and thus the CDOBs, record three different phases of ocean evolution, the early phase of the initial rift and opening of the ocean (J-belt peridotites and pyroxenites), later phase of the already developed ocean (S-belt peridotites), and also the phase of ocean closure which is evident from the structures of melánge, but also from the presence of amphibolite contact formed as a result of obduction

Petrografske, mineraloške i kemijske karakteristike boksita iz ležišta u Posušju, Bosna i Hercegovina – AGEMERA projekt istraživanja

The exploitation of bauxite in the wider area of Posušje in Bosnia and Herzegovina has been known since the first half of the 20th century, and to date more than 1100 deposits or occurrences of various sizes and structures have been discovered. Bauxite deposits of Posušje represent typical karst bauxites, formed during the emersion phase between Upper Cretaceous rudist limestones in the footwall and various carbonate and clastic rocks of Paleocene/ Eocene and Oligocene ages in the hanging wall. The most intensive mineralogical and geochemical bauxite research in these areas was carried out during the 70s and 80s. Afterwards, despite numerous newly discovered deposits, no petrographic, mineralogical and geochemical analysis on the bauxites has been published. The present study is focused on recently discovered bauxite deposits in Posušje and their petrographic and mineralogical description. The bauxites show ooidic to pelitomorphic, but in places also clastic textures. Micro-ooids and spheroids are mostly smaller than 0.1 mm, and in places fragments of the former ooid can be found. In some bauxites, pebbles of resedimented bauxite prevail, mostly larger than 2 mm but sometimes larger than 1 cm, which define their conglomerate texture. Gibbsite and boehmite are the main Al-bearing minerals of the bauxites, and diaspore has not been observed. The ratio of gibbsite to boehmite varies between deposits, and in some deposits boehmite is the only aluminium phase present. Where present, the gibbsite is developed into relatively large hypidiomorphic crystals larger than 0.25 mm, with clearly defined polysynthetic lamellae. Hematite is the dominant Fe-phase in all deposits. Although rarely, goethite-rich bauxites can be found in the form of isolated layers, with just traces or no hematite. Zircon, apatite and calcite are minor and accessory minerals, and X-ray analysis indicated significant amounts of anatase and rutile. Kaolinite was detected in only one sample. Chemical analyses indicate a negative correlation of Al and Fe content. The Al2O3 content ranges from 53.4 to 63.9 wt.%, and Fe2O3 from 22.5 to 35.2 wt.%. The SiO2 and TiO2 content varies from 1.6 to 5.6 wt.% and 3.5 to 4.6 wt.%, respectively. The chemical composition of the analysed samples defines them as ferrous bauxites. A change in the chemical composition was observed in relation to the footwall distance. The relatively high content of Zn (up to 627 ppm) gradually decreases towards host carbonates of the footwall, and a similar trend is observed in the Fe, Cr and Zr content, while Al, P, Ca and Ti, on the other hand, increase closer to the footwall. Mineralogical, petrological and chemical studies of the recently opened bauxite mines in Posušje revels heterogenic properties and indicate a complex genesis of the deposits, with possibly diverse source material

Petrografske, mineraloške i kemijske karakteristike boksita iz ležišta u Posušju, Bosna i Hercegovina – AGEMERA projekt istraživanja

The exploitation of bauxite in the wider area of Posušje in Bosnia and Herzegovina has been known since the first half of the 20th century, and to date more than 1100 deposits or occurrences of various sizes and structures have been discovered. Bauxite deposits of Posušje represent typical karst bauxites, formed during the emersion phase between Upper Cretaceous rudist limestones in the footwall and various carbonate and clastic rocks of Paleocene/ Eocene and Oligocene ages in the hanging wall. The most intensive mineralogical and geochemical bauxite research in these areas was carried out during the 70s and 80s. Afterwards, despite numerous newly discovered deposits, no petrographic, mineralogical and geochemical analysis on the bauxites has been published. The present study is focused on recently discovered bauxite deposits in Posušje and their petrographic and mineralogical description. The bauxites show ooidic to pelitomorphic, but in places also clastic textures. Micro-ooids and spheroids are mostly smaller than 0.1 mm, and in places fragments of the former ooid can be found. In some bauxites, pebbles of resedimented bauxite prevail, mostly larger than 2 mm but sometimes larger than 1 cm, which define their conglomerate texture. Gibbsite and boehmite are the main Al-bearing minerals of the bauxites, and diaspore has not been observed. The ratio of gibbsite to boehmite varies between deposits, and in some deposits boehmite is the only aluminium phase present. Where present, the gibbsite is developed into relatively large hypidiomorphic crystals larger than 0.25 mm, with clearly defined polysynthetic lamellae. Hematite is the dominant Fe-phase in all deposits. Although rarely, goethite-rich bauxites can be found in the form of isolated layers, with just traces or no hematite. Zircon, apatite and calcite are minor and accessory minerals, and X-ray analysis indicated significant amounts of anatase and rutile. Kaolinite was detected in only one sample. Chemical analyses indicate a negative correlation of Al and Fe content. The Al2O3 content ranges from 53.4 to 63.9 wt.%, and Fe2O3 from 22.5 to 35.2 wt.%. The SiO2 and TiO2 content varies from 1.6 to 5.6 wt.% and 3.5 to 4.6 wt.%, respectively. The chemical composition of the analysed samples defines them as ferrous bauxites. A change in the chemical composition was observed in relation to the footwall distance. The relatively high content of Zn (up to 627 ppm) gradually decreases towards host carbonates of the footwall, and a similar trend is observed in the Fe, Cr and Zr content, while Al, P, Ca and Ti, on the other hand, increase closer to the footwall. Mineralogical, petrological and chemical studies of the recently opened bauxite mines in Posušje revels heterogenic properties and indicate a complex genesis of the deposits, with possibly diverse source material

First occurrence of dumortierite in Croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted pegmatite

In this article, dumortierite from Croatia is described for the first time. Dumortierite formed in a pegmatite dyke cutting through Cretaceous two-mica leucogranite of the magmatic-metamorphic complex of Mt. Moslavačka Gora. The pegmatite dyke shows a magmatic mineral association of coarse-grained quartz, orthoclase, microcline and albite, less abundant muscovite, biotite, pinkish andalusite and blue-coloured prismatic dumortierite I crystals. Subsequent alteration by titanium-rich hydrothermal fluids led to partial replacement of dumortierite I and andalusite by secondary fibrous to acicular purple dumortierite II enriched in Mg and Ti. During temperature decrease perthite developed in feldspars and at a still later stage, sericite partially replaced not only feldspars but also andalusite and both types of dumortierite along grain boundaries and cracks. Final alteration at very low temperatures caused formation of clay minerals at the expense of feldspars. According to mineral chemical analyses, the feldspars are represented by albite and K-feldspar with a low albite component. Biotite corresponds to annite and its subhedral shape and chemical composition point to magmatic crystallisation from a peraluminous melt derived from a crustal source. Coarse muscovite flakes contain 1.31-1.48 wt.% FeO and 0.56-0.70 wt.% TiO2. Their Na/(Na+K) ratios (0.08–0.09) prove a magmatic origin, whereas lower ratios in sericite (0.04–0.06) indicate formation during retrogression. Magmatic muscovite is in textural equilibrium with andalusite, also implying an igneous origin for the latter, which belongs to the S3 textural type of andalusite in felsic igneous rocks. Electron microprobe analyses clearly show a strong positive correlation between Si tetrahedral deficiency (3-Si) and the sum of Al+Ti, (R2= 0.85) in both types of dumortierite, implying Al replacement by Ti. However, Al replacement by Ti is not restricted to Al in the octahedral position, as generally accepted, but most probably also in the tetrahedral position. Distinct pleochroic colours in dumortierite are usually explained by the [Fe/(Fe+Ti)]x100 factor, but according to this study, elevated Mg contents stabilize red to violet coloured dumortierite at higher [Fe/(Fe+Ti)] x100 factors than those previously suggested. Dumortierite-bearing pegmatite and host two-mica leucogranite show strong chemical similarities in their major, minor and trace element contents. Both rock types have a strong peraluminous character (ASI = 1.6 in pegmatite vs 1.8 in leucogranite), low CaO/Na2O ratios (0.11 vs 0.14), high Rb/Ba (74.5 vs 16.4) and Rb/Sr ratios (78.4 vs 43.3) as well as relatively high Al2O3/TiO2 ratios (261 vs 210). For the leucogranitic melt these characteristics indicate derivation from a pelitic source and low melting rates at relatively low temperatures. With respect to the field relationships and the chemical similarities, formation of the pegmatitic melt by fractional crystallisation during solidification of the two-mica leucogranite is inferred. Based on the mineralogical composition, the dumortierite-bearing pegmatite from Mt. Moslavačka Gora may be a member of the abyssal pegmatite class and the AB-BBe subclass. However, its formation by fractional crystallisation from a granitic melt argues against this interpretation, as all other dumortierite-bearing granitic pegmatites occur in high-grade metamorphic host rocks and are thought to be products of anatectic melting of country rocks. Therefore, the investigated pegmatite is quite unique and not fully comparable with any previously described dumortierite-bearing pegmatite worldwide

Elevated lipoprotein (a) – an independent risk factor for cardiovascular disease – recommendations for measuring and treatment

Smjernice međunarodnih stručnih društava ukazuju da je povišena koncentracija lipoproteina(a) [Lp(a)] u krvi dugoročni neovisni čimbenik rizika za razvitak aterosklerotske kardiovaskularne bolesti (ASKVB), kao i za kalcifikacijsku stenozu aortnih zalistaka. Cilj je ovog članka koji je rezultat konsenzusa nacionalnih stručnjaka iz tog područja predstaviti najnovije spoznaje o dijagnostici i sadašnjim mogućnostima liječenja bolesnika s povišenom koncentracijom Lp(a) u krvi koje su u ovom trenutku skromne, ali i naznačiti buduće mogućnosti liječenja koje su na pomolu. Zaključak koji se može postaviti na temelju dosadašnjih spoznaja upućuje da postoji neposredna korist za bolesnike u mjerenju koncentracije Lp(a), čak i ako potpuno učinkovito farmakološko liječenje još nije dostupno. Mjerenje Lp(a) olakšava bržu i pouzdaniju identifikaciju bolesnika s visokim kardiovaskularnim rizikom i bolje upravljanje tim rizikom, odnosno upućuje na potrebu intenzivnijeg smanjivanja i liječenja ostalih čimbenika rizika za ASKVB ako je Lp(a) značajnije povećan. Izražavanje koncentracije Lp(a) preporučuje se u nmol/L izmjerene metodama kalibriranim kalibratorima čija je koncentracija izražena u nmol/L.The guidelines of international professional societies indicate that elevated concentration of lipoprotein(a) [Lp(a)] in the blood is a long-term independent risk factor for the development of atherosclerotic cardiovascular disease (ASCVD), as well as for calcification stenosis of the aortic valves. The aim of this document which was produced as a consensus document of the authors who are national experts in the field is to present the latest knowledge about diagnostics and current treatment options for patients with elevated Lp(a) concentrations in the blood, which are modest at the moment, but also to indicate future treatment options that are on the horizon. The conclusion that can be made on the basis of current knowledge indicates that there is an immediate benefit for patients in measuring the concentration of Lp(a), even if fully effective pharmacological treatment is not yet available. Measurement of Lp(a) facilitates faster and more reliable identification of patients with high cardiovascular risk and better management of that risk, i.e. it indicates the need for more intensive reduction and treatment of other risk factors for ASCVD if Lp(a) is significantly increased. It is recommended to express the concentration of Lp(a) in nmol/L measured by methods calibrated with calibrators whose concentration is expressed in nmol/L