A compositional approach to the reconstruction of geochemical processes involved in the evolution of Holocene marine flooded coastal karst basins (Mljet Island, Croatia)

Past climate variations recorded in needle-like aragonites correlate with organic carbon burial efficiency as revealed by lake sediments in Croatia

“…To further investigate the role of wet versus dry conditions as potential drivers of Sr/Ca variability, we studied additional chemical elements acquired by XRF scanning, such as Br, Rb, Si, K, Na, Al, Fe, Mn, Zr, Ti and Mo, which were primarily validated by wet-chemical analysis on discrete samples, e.g., through inductively coupled plasma mass spectrometry (ICP-MS). We used all of these elements to model proxies called balances; for paleotemperature, aeolian input and paleoredox conditions via orthonormal log ratio transformation (OLR) 52 , which enabled firm statistical parameters to be established for reliable interpretations of the involved processes 53 . The methodology is fully explained in a previous study 53 and described briefly in the Methods section.…”

“…We used all of these elements to model proxies called balances; for paleotemperature, aeolian input and paleoredox conditions via orthonormal log ratio transformation (OLR) 52 , which enabled firm statistical parameters to be established for reliable interpretations of the involved processes 53 . The methodology is fully explained in a previous study 53 and described briefly in the Methods section. Ultimately, five balances were modeled, each of which is a proxy for a certain process: b3 and b4 are proxies for paleoredox conditions, b5 is a proxy for aeolian activity, and b2 is a proxy for paleoclimate Sr/Ca (rationale for the balance construction is shown in the Supplementary file, text S1, and sign matrix table used for OLR transformation is shown in the Supplementary file, table S1).…”

“…Prior to the statistical analyses, one should represent data that are originally given as elements of a simplex space in log ratio coordinates 15 . Orthonormal log ratio coordinates (olr) were used 52 , 68 to construct geochemical proxies 53 . The orthonormal basis for the olr compositional biplots was constructed using the CoDa pack 69 .…”

The relationship between the geochemical and mineralogical characteristics of Calcocambisol, colluvium and recent marine lake sediment of the narrow seashore intertidal zone: a case study from the Veliko Jezero (Mljet Island, Croatia)

“…The results of the mineralogical analyses of the marine lake sediment of Veliko Jezero showed the presence of amphibole, which may indicate an aeolian source of the material. Indeed, RAZUM et al (2020) found that the recent detrital part of the medium to coarse silt and sand fraction material in Veliko Jezero comes from aeolian sands, which are rich in minerals derived from mafic and ultramafic magmatic rocks. These observations are also in agreement with the origin of Quaternary aeolian sands deposited on the southern sides of the Mljet Island and surrounding islands (BABIĆ et al, 2013;PAVELIĆ et al, 2014;KOVAČIĆ et al, 2018).…”

“…The authors discovered that anthropogenic influences and natural processes of soil leaching and dry/wet precipitation were responsible for the elevated trace metals. RAZUM et al (2020) investigated element concentrations in a sediment core from the Veliko Jezero lake to obtain information about environmental conditions and recent sedimentation processes.…”