The 156–138 Ma Chidliak kimberlites on the Eastern Hall peninsula (EHP) of Baffin Island entrained mantle xenoliths interpreted to have been a part of the Archean North Atlantic Craton (NAC) ...lithospheric mantle. We studied 19 Chidliak eclogite xenoliths that comprise 10 bimineralic, 5 rutile-bearing, 3 orthopyroxene-bearing and 1 kyanite-bearing eclogites. We report major and trace element compositions of the minerals, calculated bulk compositions, pressures and temperatures of the rock formation and model melt extraction from viable protoliths. The eclogite samples are classified into three groups of HREE-enriched, LREE-depleted and metasomatized based on their reconstructed whole-rock REE patterns. PT parameters of the eclogites were calculated by projecting garnet–clinopyroxene temperatures onto the local
P
–
T
arrays for 65 Chidliak peridotite xenoliths. All Chidliak eclogites are equilibrated in the diamond
P
–
T
field and cluster in two groups, low-temperature (
n
= 5, 840–990 °C at 4.1–5.0 GPa) and high-temperature (
n
= 11,
T
> 1320 °C at
P
> 7.0 GPa). The reconstructed Mg-rich major element bulk compositions and trace elements patterns are similar to Archean basalts from the North Atlantic and Superior cratons and the oceanic gabbros. The LREE-depleted Chidliak eclogites could be residues after 15–55% partial melting of Archean basalt at the eclogite facies of metamorphism that led to extraction of a tonalite–trondhjemite–granodiorite melt from the EHP. The HREE-depleted eclogites may have experienced a lower degree (<10%) of partial melting. Two eclogites may have formed after the gabbro protolith based on the presence of kyanite, high Sr content of garnet and positive Eu anomalies in garnet and bulk eclogite compositions. The metasomatism is reflected in higher Ce/Yb, Sr/Y, TiO
2
or MgO of the eclogites. The average contents of MgO, FeO and CaO in NAC eclogites are statistically distinct from those in Slave craton eclogites with a probability of >95%. The former are more magnesian, less ferrous and calcic, contain more magnesian and less calcic garnets, and lower proportions of group C eclogites. The contrast may relate to the stronger NAC metasomatism by silicate–carbonate melt observed in Chidliak peridotitic mantle, or to the different formation ages of the eclogites beneath the two cratons.
The phenomena of thermal waters in the north-eastern periphery of the Zenica-Sarajevo Basin are caused by the geological structure, structural-tectonic and hydrogeological characteristics of the ...terrain. The genesis has not been fully addressed before. This paper presents the study of the genesis of thermal waters based on the geological structure, structural-tectonic and hydrogeological characteristics of the terrain, and the physiochemical and isotopic composition of water. The results provide a new contribution to the structure of this part of the Zenica-Sarajevo Basin and create a more realistic foundation for the future research of thermal water in this area.
In Bosnia and Herzegovina, Tertiary volcanic rocks occur within two geotectonically different areas: (1) in northeastern Bosnia, the wider area of Srebrenica and, (2) to a lesser extent in central ...Bosnia, the wider areas of Maglaj, Teslić and Nemila (Kolići). The major and trace element variations in the rocks surrounding Maglaj indicate their high-K calc-alkaline character, and are consistent with fractionation of the observed phenocryst assemblages (plagioclase, sanidine, biotite and hornblende). The scatter in some graphs cannot be explained by simple crystal fractionation from a common parent magma. More likely, such variations are affected by variable contribution and assimilation of continental crust within the magmas generated in the mantle. The presence of reverse zoned plagioclase phenocrysts, as well as a resorbed rim enclosing the coexisting quartz phenocrysts, can be interpreted by mixing of magmas with different temperatures and compositions.
All analyzed rocks show enrichment of the LILEs over the HFSEs and have significant negative Ta-Nb, P and Ti anomalies, and positive U and Pb anomalies, which are characteristic of subduction-related volcanic rocks generated in (post) collisional zones. Chondrite-normalized REE patterns exibit enrichment on the LREEs over the HREEs with (La/Yb)cn ranging from 21.4 to 21.9. All analyzed rocks have small negative Eu anomalies (Eu/Eu* =0.86-0.89) which suggests that plagioclase fractionation played a minor role in the genesis of the dacites. Ratios of some diagnostic elements versus SiO2 diagrams are best explained as a result of assimilation of varying degree in the continental crust during magma ascent and continuing fractional crystallization. High values of LILE/HFSE ratios in K/Ti (6.6 to 11.9), K/Zr (124-169), K/Nb (1598-2692) and Ba/Nb (44-65) and negative anomalies of Ti and Nb in the volcanic rocks surrounding Maglaj can be explained as the result of complex processes in the magmatic system originally derived from a mantle wedge.
The full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
...Graduate
Pojave termalnih voda na sjeveroistočnome obodu Zeničko-sarajevskoga bazena prouzročene su geološkom građom te strukturno-tektonskim i hidrogeološkim svojstvima terena. Pitanje njihove geneze u ...prošlosti nije u potpunosti riješeno. U ovome radu izučena je geneza termalnih voda na temelju geološke građe, strukturno-tektonskih i hidrogeoloških karakteristika terena te fizičko-kemijskoga i izotopskoga sastava voda. Dobiveni rezultati novi su prilog razmatranju strukturne građe ovoga dijela Zeničko-sarajevskoga bazena, ali i stvaranju primjerenijih postavki za buduća istraživanja ležišta termalnih voda u tomu prostoru.
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