Geokemijske i tektonomagmatske karakteristike jastučastih bazalta iz ofiolitnih melanža Dinarida

master's thesis

• Title: Geokemijske i tektonomagmatske karakteristike jastučastih bazalta iz ofiolitnih melanža Dinarida : diplomski rad
• Title (english): Geochemical and tectonomagmatic characteristics of pillow basalts from Dinaridic ophiolitic melanges : Graduate engineer of geology thesis
• Author: Sanja Simat
• Mentor: Boško Lugović (mentor)
• Committee member: Boško Lugović
• Committee member: Vesnica Garašić
• 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: 2010-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology; Mineralogy and Petrology

Abstract

Petrološke i geokemijske karakteristike blokova jastučastih bazalta alteriranih u spilite koji su
blisko asocirani s pelagičkim sedimentnim stijenama u ofiolitnim melanžima Zagorjesrednjotransdanubijske
zone, Dinaridske ofiolitne zone i Vardarske zone ukazuju na njihov sukcesivni nastanak u različitim geotektonkim okolišima. Na temelju sadržaja imobilnih elemenata u tragovima razlučene su četiri skupine bazalta: (1) alkalijski bazalti ploče jako obogaćeni LIL elementima, te LRE i HFS elementima u odnosu na HRE elemente, (2) bazalti E-MORB tipa obogaćeni LRE elementima, (3) bazalti N-MORB tipa osiromašeni LRE
elementima u odnosu na HRE elemente i (4) bazalti IAT tipa obogaćeni LRE elementima, ali s izrazito negativnom anomalijom HFS elemenata. Alkalijski bazalti vezani su za fazu intrakontinentalnog riftinga koja prethodi začetku formiranja oceanske kore. Bazalti E-MORB tipa predstavljaju prvu oceansku koru nastalu na hrptu u začetnoj fazi širenja oceana u gornjem trijasu. Bazalti N-MORB tipa tvore koru nastalu na srednjooceanskom hrptu iz već osiromašenog plašta i predstavljaju stijene zrelog oceana. Bazalti IAT tipa su stijene nastale u početnom stadiju intraoceanske subdukcije u protolučnom ekstenzijskom okolišu obducirane
ploče. Biostratigrafska analiza relativne starosti radiolarita u statigrafskoj sukcesiji s bazaltima IAT tipa ukazuje na njihove erupcije tijekom gornjeg bajocija do donjeg kalovija. Na taj način ovim radom može se pratiti razvoj oceanskog područja u Dinaridima od intrakontinenentalnog riftinga, vjerojatno krajem ladinika, do intraoceanske subdukcije tijekom srednje jure.

Abstract (english)

Abstract:
Petrological and geochemical characteristics of highly altered pillow basalts closely associated with pelagic sedimentary rocks in the blocks incorporated in the ophiolitic melanges of Zagorje–Mid-Transdanubian zone, Dinaridic ophiolite zone and Vardar zone indicate that they must have been succesively generated at various geotectonic settings. Based on the abundance of elements which are immobile during alterations the basaltic rock suite splits into four geochemical groups: (1) within plate alkali basalts with significant enrichments in LILE and HFSE over HREE, (2) E-MORB-type basalts enriched in LREE, (3) N-MORB-type basalts depleted in LREE compared with HREE and (4) IAT-type basalts with LREE
enrichment and significant HFSE depletion. Alkali basalts reflect mantle plume related
intracontinental rifing volcanism which close precedes formation of the oldest spreading ridge
crust in the proto-ocean. The remnants of this crust is represented by the E-MORB-type
volcanics which are associated in stratigraphic succesion with Upper Triassic radiolarian
cherts. N-MORB-type basalts derived from a depleted mantle and represent pure oceanic crust
of a well established ocean. IAT-type basalts developed during initiation of the intraoceanic
subduction in a proto-arc extensional setting. Biostratigraphic analysis of radiolarian
asemblage of cherts in stratigraphic succesion with IAT-type basalts revealed Upper Baiotian
to Lower Callovian ages. The results of this work provide monitoring of geodynamic
evolution of Dinaric ocean segment from thestage of intracontinental rifting, most likely of
Ladinian age, till intraoceanic subduction during Middle Jurassic.

• Keywords: jastučasti bazalti; radiolariti; ofiolitni melanž; geotektonski okoliš; Dinaridi
• Keywords (english): pillow basalts; radiolarites; ophiolite melanges; geotectonic settings; Dinarides
• Language: croatian
• URN:NBN: urn:nbn:hr:169:258762
• Study programme: Title: Geology; specializations in: Geology of mineral resources and geophysical explorations; Course: Geology of mineral resources and geophysical explorations; 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: 2015-12-09 11:21:02