Paleoekološka interpretacija miocenskih foraminiferskih zajednica lokaliteta Orešje, Medvednica

master's thesis

• Title (english): Paleoecological interpretation of the Miocene foraminiferal assemblages from Orešje locality, Medvednica Mt
• Author: Danijel Kvakan
• Mentor: Đurđica Pezelj (mentor)
• Committee member: Vlasta Ćosović (predsjednik povjerenstva)
• Committee member: Marijan Kovačić (član povjerenstva)
• Committee member: Đurđica Pezelj (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geology); Zagreb
• Defense date and country: 2022-02-23, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology; Geology and Paleontology

Abstract

Uzorci lapora su prikupljeni na sjeveroistočnom dijelu Medvednice, u kamenolomu Donje Orešje. Uzorci su obrađeni metodom šlemanja, a zatim je mikrofosilni materijal analiziran pod mikroskopom. Utvrđena je raznolika zajednica foraminifera, te je određeno ukupno 27 rodova i 38 vrsta bentičkih foraminifera.
Dubina taložnog okoliša je određena na osnovu odnosa planktonskih i bentičkih foraminifera koji upućuje na oscilacije u dubini od srednjeg do unutrašnjeg šelfa. Na temelju bentičkih foraminifera određena je starost naslaga i napravljena paleoekološka rekonstrukcija okoliša. Identifikacija usko provodnih vrsta bentičkih foraminifera Bulimina insignis i Pappina neudorfensis, ukazala je da je starost naslaga srednji miocen - gornji baden. U svim analiziranim uzorcima dominiraju foraminifere s perforatnom stijenkom i infaunalni oblici bentičkih foraminifera. Izračunati indeksi bioraznolikosti upućuju da raznolikost zajednice pada duž profila, dok istovremeno raste dominacija, ali do uzorka 5/9, gdje je situacija obrnuta. Također, duž profila oscilira i količina kisika na morskom dnu i uvjeti se mijenjanju od visoko oksičnih, preko nisko oksičnih, do srednje oksičnih.

Abstract (english)

Marl samples were collected in the northeastern part of Medvednica Mt., in the Donje Orešje quarry. The samples were processed by the method of wet sieving and then the microfossil material was analyzed under a microscope. A diverse assemblages of foraminifera has been identified, and a total of 27 genera and 38 species of benthic foraminifera have been identified. The depth of the paleoenvironment was determined on the basis of the ratio of planktonic and benthic foraminifera, which indicates oscillations in the depth from the middle to the inner shelf. Based on benthic foraminifera, the age of the deposits was determined and paleoecological reconstruction of the environment was made. Identification of indeks species of benthic foraminifera Bulimina insignis and Pappina neudorfensis, indicated that the age of the deposits is the Middle Miocene - Upper Badenian. Foraminifera with perforated wall and infaunal forms of benthic foraminifera dominate in all analyzed samples. The calculated biodiversity indices indicate that assemblages diversity decreasing along the profile, while dominance increasing at the same time, but up to the 5/9 sample, where the situation is reversed. Also, the oxygen content on the sea floor oscillates along the profile and the conditions change from high oxic, through low oxic, to moderately oxic.

• Keywords: bentičke foraminifere; baden; paleookoliš; Medvednica
• Keywords (english): Benthic foraminifera; Badenian; Paleoenvironment; Medvednica Mt.
• Language: croatian
• URN:NBN: urn:nbn:hr:217:269052
• Study programme: Title: Graduate university study of 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: Open access
• Created on: 2022-07-06 10:19:59