Naslov
Biometric changes in planktonic foraminifera Pseudohastigerina micra from the upper Eocene sediments of the island of Hvar

Autori
Pejnović, Igor ; Ćosović, Vlasta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
7th Faculty of Science PhD Student Symposium Book of Abstracts / Pavlek, Katarina - Zagreb : Prirodoslovno-matematički fakultet Sveučilišta u Zagrebu, 2023, 57-57

ISBN
978-953-6076-01-7

Skup
The seventh Faculty of Science PhD Student Symposium

Mjesto i datum
Zagreb, Hrvatska, 21.04.2023. - 22.04.2023

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
planktonic foraminifera ; biometrics ; Eocene ; flysch ; Hvar

Sažetak
Nine samples were collected from a 50 m thick sediment succession at Zaraće cove, island of Hvar. Planktonic foraminifera tests were extracted from the samples and in six samples foraminifera were abundant to allow further paleoecologic studies. The samples fall within the E15, Globigerinatheka index, planktonic biozone of [1], which corresponds to upper Eocene (Priabonian) age. During this age average sea temperature was on a steady decline. The hypothesis of this study was to track changes in foraminiferal tests sizes to detect changes in temperature, knowing that tests are getting smaller and smaller as temperature decreases [2]. For this Pseudohastigerina micra (Cole 1927) was selected for the study. The species was abundant throughout most of the Zaraće section and, up to date, the only biometric study was done solely for phylogenetic purposes [3]. Around 50 specimens (tests) of P. micra were randomly picked from the 63-250 μm size fraction of each of the five samples (those samples that contained sufficient number of individuals). Each test was observed under a stereoscopic microscope and photographed in side and aperture views. Using ImagePro 4 software following test parameters were measured: maximum diameter of the test, height of the final chamber, width of the final chamber and aperture shape. In the older part of Zaraće section, P. micra shows a steady decrease in maximum test diameter, width and height of the final chamber, with lowest values measured in the sample taken just below the 22nd meter of the section. This coincides with a decrease in planktonic foraminifera diversity and may point towards increasing environmental stress. Towards the younger part of the section (above the 22nd meter), and up until foraminifera become rare or absent, P. micra tests have features similar to those found in the oldest part of the section.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA