Jurski amfiboliti iz miocenskih konglomerata Medvednice

master's thesis

• Title: Jurski amfiboliti iz miocenskih konglomerata Medvednice : diplomski rad
• Title (english): Jurassic amphibolites in the Miocene conglomerates of Medvednica Mt. : master's thesis
• Author: Irena Tarnaj
• Mentor: Vesnica Garašić (mentor)
• Committee member: Vesnica Garašić
• Committee member: Sibila Borojević Šoštarić
• Committee member: Bruno Tomljenović
• Granter: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Mineralogy, Petrology and Mineral Resources); Zagreb
• Defense date and country: 2013-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology; Mineralogy and Petrology

Abstract

Amfiboliti iz miocenskih konglomerata Medvednice mineralne parageneze: hornblenda + plagioklas +
klinopiroksen ± epidot tipične su za amfibolitni facijses nižeg do središnjeg odjeljka srednjeg stupnja
metamorfizma. Prema kemijskim analizama minerala amfiboli odgovaraju hornblendi i tschermakitu,
a u uzorku kataklastičnog amfibolita pargazitu. Klinopiroksen je diopsid. Plagioklas je alteriran u
gline, sericit i albit, osim u kataklastičnom amfibolitu. Na rubovima hornblenda prelazi u aktinolit,
tremolit i epidot te uz pojave albita i sericita ukazuje na postojanje retrogradnog metamorfizma.
Na kataklastičnom amfibolitu koji sadrži primarne plagioklase (oligoklas do andenzin) napravljena je
geotermobarometrija. Dobivene temperature od 540-610 °C i tlakovi od 6-8 kb odgovaraju utvrđenoj
mineralnoj paragenezi amfibolitnog facijesa nižeg do središnjeg odjeljka srednjeg stupnja
metamorfizma.
Klinopiroksen predstavlja reliktni mineral u amfibolitima i ukazuje na magmatsko porijeklo protolita,
što je u skladu s geokemijskim karakteristikama ovih amfibolita, za koje je ranije već utvrđeno da su
im protoliti bili alkalijski i toleiitni bazalti nastali u ocenskom području.
Starost je utvrđena 40Ar-39Ar metodom na uzorku MD101 i odgovara razdoblju srednje jure (176.7 ±1.
8 milijuna godina).
Petrološke i geokemijske karakteristike amfibolita iz miocenskih koglomerata Medvenice upućuju na
zaključak da amfiboliti predstavljaju relikte metamorfne podloge lercolitima u jurskom ofiolitnom
kompleksu Banije.

Abstract (english)

Abstract: Amphibolites in the miocene conglomerates of Medvednice Mt. containing mineral paragenesis
hornblende + plagioclase ± epidote are typical of amphibolite facies of lower to middle part of
medium grade metamorphism. According to chemical analyzes of minerals amphibole corresponds to
hornblende and tschermakite and in the sample of the cataclastic amphibolites it is pargasite.
Clinopyroxene is diopside. Plagioclas is altered in clay minerals, sericite and albite, excluding
cataclastic amphibolites. Actinolite, tremolite and epidote occurring at the rims of hornblende together
with albite and sericite in plagioclase point to retrograde metamorphism.
Geothermobarometric calculations were made in the cataclastic amphibolite which contain primary
plagioclase (oligoclas to andesine). Obtained temperature of 540 to 610 °C and pressure of 6 to 8 kb
correspond to the established mineral paragenesis of the amphibolite facies of lower to middle part of
medium grade metamorphism.
Clinopyroxene is a relict mineral in amphibolites and indicates a magmatic protholite, what is in
accordance with geochemical characteristic of these amphibolites for which earlier have been found
that the protoliths were alkali and toleiite basalts originated in the ocean area.
Age is determinated by 40Ar-39Ar method on the sample MD101 and responds to the middle Jurassic
(176.7 ±1. 8 Ma).
Petrological and geochemical characteristics of amphibolites from Miocene conglomerate of the
Medvednica Mt. indicate that amphibolites are relicts of metamorphic sole of lercolites in Jurassic
ophiolite complex of Bania.

• Keywords: amfiboliti; geotermobarometrija; starost; protoliti; metamorfna podloga
• Keywords (english): amphibolites; geotermobarometry; Middle Jurassic; protolite; metamorphic sole
• Language: croatian
• URN:NBN: urn:nbn:hr:169:303628
• Study programme: Title: Geology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra geologije (magistar/magistra geologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2016-01-22 10:09:57