PLAGIOGRANITI IZ OFIOLITNIH KOMPLEKSA ZONE DINARIDA I VARDARA

Geochemical dana of plagiogranites associated with ophiolite conplexes of Central Dinaride Ophiolite Belt (CDOB) and Vardar Zone Ophiolite Belt (VZOB) are presented. Plagiogranites occur as dikes or small intrusive bodies in the upper part of the gabbrodolerite or diabase section in the ophiolite sequence. On the basis of normative An-Ab-Or diagram most of studied plagiogranites are classified as trondhjemites. They are typically low in K2O, Rb and MgO and contain low to moderate Al2O3, but light SiO2 and Na2O. Their ocean ridge granite normalized patterns of trace elements displaying low contents of HFS and high contents of LIL elements are very similar to those of the volcanic arc granites. But assuming that in trace element pattern elevated K2O and Rb contents are result of alteration, the studied plagiogranites have also strong similarity with typical Troodos supra-subduction ocean ridge granite. The using of Peacock indeks reveals that they are characterized by calcic character what is typical for supra-subduction ocean ridge granite. The studied plagiogranites are probably formed in extensional conditions above a subduction zone and in terms of their origin the most probably related to crystal-liquid differentiation process.Prikazani su geokemijski podaci plagiogranita koji se nalaze u ofiolitnim kompleksima Centralne ofiolitne zone Dinarida (CDOB) i Vardarske ofiolitne zone (VZOB). Plagiograniti se pojavljuju kao dajkovi ili mala intruzivna tijela u gornjem dijelu gabro-doleritne ili dijabazne jedinice ofiolitne sekvence. Na temelju normativnog An-Ab-Or dijagrama većina proučavanih plagiogranita je klasificirana kao trondhjemiti. Oni tipično imaju niske sadržaje K2O, FeO i MgO, niski do srednji sadržaj Al2O3, ali visoke sadržaje SiO2 i Na2O. Usporedba elemenata u tragovima u plagiogranitima s onima tipičnim za granite oceanskog grebena pokazuje da plagiograniti imaju viši sadržaj elemenata velikog radijusa (LIL elementi), a niži sadržaj elemenata malog radijusa i visokog naboja (HFS elementi). Slično ponašanje elemenata u tragovima pokazuju i graniti vulkanskog luka uspoređeni s onima u granitima oceanskog grebena. Međutim, ako se pretpostavi da je povišeni sadržaj K2O i Rb u proučavanim plagiogranitima rezultat alteracije, tada oni imaju također veliku sličnost s Trodos granitom koji je tipični predstavnik granita suptra-subdukcijskih oceanskih grebena. Upotreba Peacock indeksa polazuje da su plagiograniti karakterizirani kalcijskim karakterom što je tipično za granite supra-subdukcijskih oceanskih grebena. Proučavani plagiograniti su vjerovatno formirani u ekstenzijskim uvjetima iznad subdukcijske zone, a njihov postanak je najvjerovatnije vezan za procese kristalno-likvidne diferencijacije

METARHYOLITES OF VRANICA MOUNTAIN IN PALEOZOIC OF CENTRAL BOSNIA

Metarioliti Vranice planine su stijene naglašene porfirne strukture u kojima se kao fenokristali nalaze kvarc, K-feldspat i vrlo rijetki albit. Osnova je mikrokristalna, karakterizirana sitnolistićastim fengitom, biotitom i područjima u kojima granofirski prorastaju kvarc i feldspati. Akcesorni minerali su ilmenit, rutil, apatit, cirkon i klorit. Metarioliti su peraluminijske stijene (PI=1,5-4,1), naglašenog kalcijskog karaktera (K2O/Na2O=1,3-13,8). Inkompatibilni elementi su vrlo obogaćeni u odnosu na prosjećni sustav hondrita, što ukazuje na krustalno porijeklo magmi metariolita. Iako se fengiti najčešće nalaze u stijenama visokog tlaka, fengiti metariolita Vranice planine najvjerojatnije pripadaju rjeđoj grupi fengita koji se nalaze u stijenama niskih do srednjih tlakova.Metharyolites of Vranica mountain are roks of emphasized porphyritic texture containing phenocrysts of quartz, K.feldspar and very rarely albite. The groundmass is microcrystallinic, characterized by finegrained phengite, biotite and area consisting of granophyric intergrowths of quartz and feldspar. Accessory minerals are ilmenite, rutila, apatite, zircon and chlorite. Metarhyolites are peraulminous rocks (PI=1.-4.1) having dominantly potassium character (K2O/Na2O=1,3-13,8). Incompatible elements are enriched relative to the normalizing chondrite composition, pointing to the crustal origin of metarhyolite magma. Although phengites typically occur in high pressure rocks, it seems that phengites of metarhyolites of Vranica mountain belong to the seldom group of phengites occurring in the low to medium pressure rocks

MEĐUSOBNI ODNOSI MINERALA I NJIHOVA KEMIJA U NEKIM BAZIČNIM MAGMATSKIM STIJENAMA OFIOLITNOG KOMPLEKSA BANIJE, HRVATSKA

Mineral relationships and their chemistry were studied in some basic magmatic rocks of Banija ophiolite complex. On the basis of mineral and structural characteristics three kind of rocks are distinguished: metadiabase I (being characterized by secondary amphibole), metadiabase II (being characterized by secondary albite) and spilite. Detailed chemistry of all mineral phases, specially of zoned clinopyroxenes and zoned amphiboles is given. The black opaque phases consist of different Fe-Ti-Mn oxides (ilmenite, Mn-ilmenite, magnetite, Ti-magnetite, ferropseudobrookite) being often at the rims replaced by Al- and Fe-rich titanite. All rocks are hydrothermally metamorphosed whereby amphibole replaced partly or completely clinopyroxene and plagioclase was altered in albite, prehnite, pumpellyite and/or sericite. Secondary chlorite occurs too. The whole rock chemistry of each studied rock corresponds to tholeiitic basalts.Međusobni odnosi minerala i njihova kemija proučavani su u nekim bazičnim magmatskim stijenama ofiolitnog kompleksa Banije. Na temelju mineralnih i stukturnih karakteristika razlikuju se tri vrste stijena: metadijabazi I (karakterizirani sekundarnim amfibolom), metadijabazi II (karakterizirani sekundarnim albitom) i spilit. Dana je detaljna kemija svih mineralnih faza, osobito zoniranih klinopiroksena i zoniranih amfibola. Crne opâke faze sastoje se od različitih Fe-Ti-Mn oksida (ilmenit, Mn-ilmenit, magnetit, Ti-magnetit, Fe-pseudobrukit) koje su često na rubovima potisnute Al- i Fe-bogatim titanitom. Sve su stijene hidrotermalno metamorfozirane pri čemu je amfibol djelomično ili potpuno potisnuo klinopiroksen, a plagioklas je izmijenjen u albit, prehnit, pumpeliit i/ili sericit. Pojavljuje se također i sekundarni klorit. Ukupna kemijska analiza svake proučavane stijene odgovara toleitskom bazaltu

Assessing recovery from acidification of European surface waters in the year 2010: evaluation of projections made with the MAGIC model in 1995

In 1999 we used the MAGIC (Model of Acidification of Groundwater In Catchments) model to project acidification of acid-sensitive European surface waters in the year 2010, given implementation of the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (LRTAP). A total of 202 sites in 10 regions in Europe were studied. These forecasts can now be compared with measurements for the year 2010, to give a “ground truth” evaluation of the model. The prerequisite for this test is that the actual sulfur and nitrogen deposition decreased from 1995 to 2010 by the same amount as that used to drive the model forecasts; this was largely the case for sulfur, but less so for nitrogen, and the simulated surface water [NO3–] reflected this difference. For most of the sites, predicted surface water recovery from acidification for the year 2010 is very close to the actual recovery observed from measured data, as recovery is predominantly driven by reductions in sulfur deposition. Overall these results show that MAGIC successfully predicts future water chemistry given known changes in acid deposition

Addressing climate change with behavioral science:A global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions' effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior-several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people's initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors.</p

Addressing climate change with behavioral science: a global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions’ effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior—several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people’s initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors