Beschreibung: This data set includes δ¹³C and F¹⁴C of bulk OC in two nearshore sediment cores collected by the piston corer from coastal South China Sea. These data could help us to constrain the anthropogenic perturbations of different terrestrial OC export to the coastal ocean.

Beschreibung: This data set includes F¹⁴C of Fatty acids in two nearshore sediment cores collected by the piston corer from coastal South China Sea. These data could help us to constrain the anthropogenic perturbations of different terrestrial OC export to the coastal ocean.

Beschreibung: This data set includes nuclide activities, grain size, content, δ¹³C and F¹⁴C of bulk OC and Fatty acids in two nearshore sediment cores collected by the piston corer from coastal South China Sea. These data could help us to constrain the anthropogenic perturbations of different terrestrial OC export to the coastal ocean.

Beschreibung: In November 2016, the first Mini-Carbon-Dating-System (MICADAS) manufactured by Ionplus AG was delivered and installed at the Alfred-Wegener-Institute (AWI), Germany. The new facility includes a graphitization unit (AGE3) connected with an elementar analyser (EA), a carbonate handling system (CHS), and a gas inlet system (GIS). The main goal for the facility at AWI will be the precise and independent dating of carbonaceous materials in marine sediments, sea-ice, and water to address various processes of the global carbon cycling. A particular focus will be on sediments from the high latitude oceans, in which radiocarbon-based age models are often difficult to obtain due to the scarcity of carbonate microfossils. One advantage of the MICADAS is the potential to analyse samples, which contain only a small amount of carbon as CO2 gas. For example, it will be possible to determine 14C ages of samples of foraminifera from carbonate-lean sediments, allowing for paleoclimate reconstructions in key locations for Earth’s climate system such as the Southern ocean. Likewise, compound-specific 14C analyses receive growing attention in carbon cycle studies and require handling of small samples of typically 〈100µg carbon. The wide range of applications encompassing gas analyses of foraminifera and compound-specific analysis as well as analyses of graphite targets requires establishing routine protocols of various methods of sample preparation, as well as thorough assessment of the respective carbon blanks. We report on our standard procedures for samples of organic matter from sediments or water including carbonate removal, combustion and graphitization using the AGE3 coupled to the EA, as well as on the methodology applied for carbonate samples using the CHS system and the GIS. We have investigated different sample preparation protocols and present the initial results using materials of known age. Additionally, we present the first results of our assessment of process blanks.

Beschreibung: The radiocarbon analysis laboratory at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) is equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System). The laboratory provides routine 14C analyses on bulk organic matter, plant fragments, dissolved and particulate organic matter, individual molecular lipids, and carbonate (micro-) fossils with the aim to foster international research efforts in vulnerable high latitudes. The AWI MICADAS allows AMS 14C analysis on graphite targets as well as on CO2 samples via gas injection into the hybrid ion source. The laboratory thus provides reliable datasets even if only small amounts of sample material are available, a problem often encountered in polar research. Here we describe the standard operation procedures and sample preparation methods employed, and demonstrate the instrument performance and data quality based on repeat analysis of international reference materials.

Beschreibung: In November 2016, the first Mini-Carbon-Dating-System (MICADAS) manufactured by Ionplus AG was delivered and installed at the Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research (AWI), Germany. After one year of establishing the instrument and preparation methods, we started routine operation for scientific purposes in January 2018. The new facility includes a graphitization unit (AGE3) connected to an elemental analyser (EA) or a carbonate handling system (CHS), and a gas inlet system (GIS). The facility at AWI focuses on analysing carbonaceous materials from samples of marine sediments, sea-ice, and water to investigate various aspects of the global carbon cycle. A particular emphasis will be on sediments from high-latitude oceans, in which radiocarbon-based age models are often difficult to obtain due to the scarcity of carbonate microfossils (e.g., foraminifera). One advantage of the MICADAS is the potential to analyse samples as CO2 gas, which allows radiocarbon measurements on samples containing as little as 10 µgC. For example, it is possible to determine 14C ages of foraminifera from carbonate-lean sediments allowing paleoclimate reconstructions in key locations for the Earth’s climate system, such as the Southern Ocean. Likewise, compound-specific 14C analyses receive growing attention in carbon cycle studies and require handling of small samples of typically 〈100 µgC. The wide range of applications including gas analyses (e.g., foraminifera and isolated compounds), and graphite targets require establishing routine protocols for various methods including sample preparation and precise blank assessment. We report on our standard procedures for dating organic matter from sediments or water including carbonate removal, combustion and graphitization using the AGE3 coupled to the EA, as well as on the methodology applied for carbonate samples using the CHS system and the GIS. We have investigated different sample preparation protocols and present the results using international standard reference materials (e.g., IAEA-C2 F14C = 0.4132 + 0.0052 (n= 14); Ref = 0.4114 + 0.0003). Additionally, we present the first results of process blanks for sediments (Eocene Messel shale F14C= 0.0007; equivalent to an conventional 14C age of 〉 52000yr (n=29)), as well as Eemian foraminifera (F14C = 0.005; equivalent to an conventional 14C age of 〉42700yr (n=98)). We are also presenting results of samples processed and analysed as graphite and directly as gas showing a good reproducibility irrespective of the method used.

Beschreibung: In November 2016, the first MICADAS manufactured by Ionplus AG was delivered and installed at the Alfred-Wegener-Institute (AWI), Germany. After one year of establishing the instrument and preparation methods, we started routine operation for scientific purposes in January 2018. In the talk, we will present varying reasons for technically related downtimes of the MICADAS_15 and solutions to reduce them. We will also present an outlook of wishes for future applications.