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Your search keyword '"Garbe-Schönberg, Dieter"' showing total 134 results
Start Over Author "Garbe-Schönberg, Dieter" Publisher elsevier b.v.
134 results on '"Garbe-Schönberg, Dieter"'

2. Native sulfur at the seafloor: Composition and origin

Author

Dekov, Vesselin M., Koschinsky, Andrea, Yamanaka, Toshiro, Petersen, Sven, Paul, Sophie A.L., Kleint, Charlotte, Pelleter, Ewan, de Lange, Gert J., Kürzinger, Victoria, Garbe-Schönberg, Dieter, Ilieva, Monika, Fouquet, Yves, and Rouxel, Olivier

Published
2024
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30. A first look at the gallium-aluminium systematics of Early Earth's seawater: Evidence from Neoarchean banded iron formation.

Author

Ernst, David M., Garbe-Schönberg, Dieter, Kraemer, Dennis, and Bau, Michael

Subjects
*MAGNETITE, *BANDED iron formations, *IRON, *RARE earth metals, *SEAWATER, *NEOARCHAEAN
Abstract

Geochemical proxies archived in banded iron formations (BIFs) can provide information on the physico-chemical conditions in the Precambrian atmosphere-hydrosphere system and the element sources to ambient Early Earth's seawater. We here report results of the first investigation of the Ga-Al systematics of BIFs and use adjacent magnetite and metachert bands of the well-studied and very pure 2.7 Ga-old Temagami BIF in Ontario, Canada, in an attempt to test the suitability of the Ga/Al ratio as a geochemical proxy. Due to very low Ga concentrations in BIFs and multiple mass interferences on the stable isotopes 69Ga and 71Ga, we conducted comparative analyses of dissolved samples with sector-field (SF-)ICP-MS and tandem ICP-MS/MS as well as laser-ablation (LA-)SF-ICP-MS on nano-particulate pressed powder tablets (NP tablets). The unexpected results indicate uniform Ga/Al weight ratios between 2.0×10−4 and 7×10−4 for the Temagami BIF, i.e. Ga/Al ratios that are slightly above those of potential clastic detritus but well below those of modern seawater or marine hydrothermal fluids. Consistent results from solution SF- and ICP-MS/MS and a two-component mixing experiment with BIF reference material IF-G and synthetic pure quartz sand corroborate the high analytical quality of these Ga and Al data. The Ga/Al ratios of the metachert bands show the same range of Ga/Al ratios as the magnetite bands and appear to be dominated by small amounts of finely dispersed Fe oxide particles that were deposited together with the chert. The Ga/Al ratios of the magnetite bands either suggest that (in contrast to other trace elements such as the rare earth elements and Y) Ga and Al were fractionated from each other during scavenging from Archean seawater by Fe (oxyhydr)oxides or that ambient Temagami seawater had significantly lower Ga/Al ratios than modern seawater, possibly due to different weathering, riverine, and estuarine processes in the Archean. While these first results demonstrate the potential of Ga-Al systematics as an additional geochemical tool for studies of Early Earth, they also reveal the knowledge gaps that still need to be addressed in future investigations. [ABSTRACT FROM AUTHOR]

Published
2023
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44. First record of stable isotopes (δ13C, δ18O) and element ratios (Mg/Ca, Sr/Ca) of Middle to Late Jurassic belemnites from the Indian Himalayas and their potential for palaeoenvironmental reconstructions.

Author

Alberti, Matthias, Fürsich, Franz T., Pandey, Dhirendra K., Andersen, Nils, Garbe-Schönberg, Dieter, Bhosale, Suraj, Chaskar, Ketan, and Habermann, Jörg M.

Subjects
STABLE isotopes, CATHODOLUMINESCENCE, SCANNING electron microscopy, FOSSILS, OROGENY, GEOCHEMISTRY
Abstract

Middle to Late Jurassic belemnites from the Spiti and Zanskar valleys in the Indian Himalayas were used for stable isotope (δ13C, δ18O) and element (Mg/Ca, Sr/Ca) analyses. Although the Himalayan orogeny deformed and altered a large portion of the collected fossils, cathodoluminescence and scanning electron microscopy in combination with analyses of iron and manganese contents allowed the identification of belemnites believed to still retain their original chemical composition. Results indicate a long-term temperature decrease from the Middle Callovian–Oxfordian to the Tithonian, which is proposed to have been caused by a concomitant drift of eastern Gondwana into higher palaeolatitudes. Reconstructed absolute temperatures depend on the used equation and assumed δ18O value of seawater, but most likely varied between 17.6 °C to 27.6 °C in the Kimmeridgian and Tithonian with average values between 22 °C to 24 °C. This way, temperatures were similar to slightly warmer than today at comparable latitudes. The reconstruction of absolute temperatures for the Middle Callovian–Oxfordian was hindered by a larger number of poorly preserved belemnites representing this time interval. [ABSTRACT FROM AUTHOR]

Published
2021
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50. Zinc distribution and localization in primed maize seeds and its translocation during early seedling development.

Author

Imran, Muhammad, Garbe-Schönberg, Dieter, Neumann, Günter, Boelt, Birte, and Mühling, Karl H.

Subjects
*EFFECT of zinc on plants, *PLANT translocation, *CORN seeds, *SEEDLINGS, *PLANT development, *EFFECT of stress on plants
Abstract

Zinc (Zn) priming is a technique used to increase seed Zn reserves for improving seed quality, crop growth, and enhancing stress tolerance in crop plants. The present study demonstrated the effect of water and Zn priming on the distribution and accumulation of endogenous and primed Zn in maize seeds ( Zea mays L.). Zn concentration in unprimed, water and Zn primed seeds and germinated seedlings were analyzed by ICP-MS (Inductivity Coupled Plasma Mass Spectroscopy). DTZ (Diphenyle Thio-Carbazone) staining method and LA-ICP-MS (Laser Ablation Inductivity Coupled Plasma Mass Spectroscopy) scanning was used for showing Zn distribution and localization in the seeds. Zn priming significantly increased Zn concentration and content in seeds. Results of ICP-MS analysis showed a substantial increase in the testa and endosperm tissues after Zn priming. DTZ staining and LA-ICP-MS scanning of maize seeds revealed an uneven distribution of Zn in water and Zn primed seeds. Laser ablation data of water primed maize seeds demonstrated a significant (p < 0.05) relocation of endogenous Zn from the aleurone layers towards the inner endosperm. Zn priming increased endosperm Zn content 3-fold compared with water primed seeds, while in the testa this increase was 50-fold. Furthermore, Zn priming significantly (p < 0.05) increased the biomass of 10-d old maize seedlings grown in rolls of filter paper. Translocation of primed Zn towards shoots and roots was double than that of endogenous Zn in unprimed and water primed maize seeds. This is the first report of the distribution and accumulation of primed Zn in maize seeds. Further investigations are needed to understand the binding capacity of the different tissues within maize seeds and the retranslocation of primed Zn during early seedling development and plant growth. [ABSTRACT FROM AUTHOR]

Published
2017
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