Project Details
Projekt
Calcium isotope fractionation during transport and recrystallisation processes in marine deep sea sediments
Applicant
Professor Dr. Harald Strauß, since 6/2018
Subject Area
Palaeontology
Term
from 2014 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 261171302
Biogenic marine calcium carbonate shells are important archives for changes in the System Earth through Earth history, as their element and isotopic composition is used for many paleo-environmental proxies. The reliability of those proxies depends not only on primary factors but also on the preservation, which in turn depends on processes like partial dissolution and recrystallization.Sediments retrieved during IODP Expeditions 320/321 provide well preserved high resolution archives throughout the Cenozoic; they are hence the basis for important paleoclimate reconstructions. Nevertheless, despite the overall good preservation, porewater analyses revealed indications for carbonate recrystallization. A tool for the investigation of diagenetic processes in marine sediments, including recrystallization, is the isotopic composition of calcium (Ca). One of the main aims of this study is to use Ca isotopes to determine recrystallization rates of the carbonate sediments drilled during IODP Exp. 320/321 to evaluate the preservation of the proxy archives. At several drill locations, the Ca isotope composition of the porewater and corresponding sediment shows characteristic profiles. First results obtained in the project indicate that besides recrystallisation, diffusion of Ca in the porewater plays an important role and has to be considered when modelling recrystallization rates. Isotope fractionation during diffusive Ca transport is a process that has not been fully characterised yet. During the ongoing project we will conduct experiments to quantify mass dependent isotope fractionation during diffusion through sediments. The results will be incorporated in the determination of recrystallization rates and will help to avoid systematic errors during modelling. The final goal of the project is to contribute to a better understanding of processes in porewaters of marine sediments.
DFG Programme
Infrastructure Priority Programmes
Co-Investigator
Privatdozent Dr. Nikolaus Gussone
Ehemalige Antragstellerin
Dr. Barbara Teichert, until 6/2018
