Vsebnosti niklja in kroma v flišnih kamninah v porečju reke Dragonje

raziskovalna naloga

Zala Žarkovič (Author), Nastja Rogan (Mentor)

Abstract

V raziskovalni nalogi je predstavljena detajlna mineraloška in geokemična analiza flišnih kamnin in prodnikov v porečju reke Dragonje. Flišne kamnine obravnavanega območja predstavljajo zaledje in vir sedimentov Sečoveljskih solin in priobalnih morskih sedimentov, kjer naj bi dokazano prihajalo do povišanih vsebnosti Ni in Cr. Pregled vzorcev z optično mikroskopijo je pokazal prisotnost nepresevnih mineralov, ki bi lahko bili potencialni nosilci težkih kovin. Z rentgensko praškovno difrakcijo (XRD) smo določili mineralno sestavo vzorcev, kjer sta v najvišjih odstotkih prisotna kremen in kalcit, v manjših deležih pa so prisotni tudi dolomit, kaolinit, muskovit, mikroklin, albit, klorit, ilit, pirit in hematit. S pomočjo visoko resolucijske masne spektrometrije (HR-ICP-MS) smo v vzorcih določili vsebnosti glavnih oksidov in slednih prvin/težkih kovin. V vseh vzorcih prevladujeta SiO2 in CaO, katerima sledijo Al2O3, Fe2O3, MgO, K2O, Na2O in TiO2. Pri analizi vsebnosti težkih kovin pa dominirata Ni in Cr, katerih vsebnosti so najvišje pri vzorcih s preperelim delom kamnine, s čimer je povezana izomorfna substitucija Ni in Cr ionov. Rezultati SEM-EDS mikroskopije so pokazali, da so v vzorcu DP9A prisotni Cr-spineli, ki posledično predstavljajo vir Cr in tako potrjujejo domnevo o nepresevnih mineralih, kot potencialnih virih težkih kovin. Ker so bile vsebnosti Ni v dotičnem vzorcu zelo nizke, ga s SEM-EDS analizo nismo zasledili, predvidevamo pa, da se pojavlja v piritu, kjer se izomorfno nadomeščata Fe in Ni ion.

Keywords

nikelj;krom;flišne kamnine;geokemija;Dragonja;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.11 - Undergraduate Thesis
Organization:	UL NTF - Faculty of Natural Sciences and Engineering
Publisher:	[Z. Žarkovič]
UDC:	55
COBISS:	83925507
Views:	261
Downloads:	33
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	nickel and chromium contents in flysch rocks in the Dragonja river basin
Secondary abstract:	The research paper presents detailed mineral and geochemical analysis of flysch rocks and gravel-stones in Dragonja river basin. Flysch rocks of researched area represent the surroundings and source of Sečovlje Salina sediments and coastal marine sediments, that contain high concentrations of Ni (nickel) and Cr (chromium). The optical microscopy has shown presence of opaque minerals which could be the potential carriers of heavy metals. X-ray powder diffraction (XRD) was used to determine mineral composition of the samples, in which quartz and calcite have the highest percentage in comparison to other minerals like dolomite, kaolinite, muscovite, microcline, albite, chlorite, illite, pyrite and hematite that have lower shares. High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) was used to identify major oxides and trace elements/heavy metals of samples. In all the samples SiO2 in CaO strongly dominate and are followed by Al2O3, Fe2O3, MgO, K2O, Na2O in TiO2. The analysis of heavy metals concentrations has shown the highest content of Ni and Cr. The highest ppm numbers of Ni and Cr are in weathered parts of rocks, which can be explained with isomorphic substitution of Ni and Cr ions. The results of SEM-EDS microscopy have shown that the sample DP9A has Cr-spinels which consequently represent the source of Cr and have confirmed the thesis of opaque minerals as potential sources of heavy metals. Because of very low contents of Ni in sample, Ni sources with SEM-EDS analysis couldn´t be identified. We predict that source of Ni is mineral pyrite, in which isomorphic substitution of Fe and Ni ions plays its part.
Secondary keywords:	nickel;chromium;flysch rocks;geochemistry;Dragonja;
Type (COBISS):	Final paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Naravoslovnotehniška fak., Oddelek za geologijo
Pages:	XI, 46 f.
ID:	13545884