Blar i forfatter "Lumiste, Kaarel"

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    • Authigenesis of biomorphic apatite particles from Benguela upwelling zone sediments off Namibia: The role of organic matter in sedimentary apatite nucleation and growth 

      Mänd, Kaarel; Kirsimäe, Kalle; Lepland, Aivo; Crosby, Chris H.; Bailey, Jake V.; Konhauser, Kurt O.; Wirth, Richard; Schreiber, Anja; Lumiste, Kaarel (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-30)
      Sedimentary phosphorites comprise a major phosphorus (P) ore, yet their formation remains poorly understood. Extant polyphosphate‐metabolizing bacterial communities are known to act as bacterial phosphate‐pumps, leading to episodically high dissolved phosphate concentrations in pore waters of organic‐rich sediment. These conditions can promote the precipitation of amorphous precursor phases that are ...

    • Constraining the conditions of phosphogenesis: Stable isotope and trace element systematics of Recent Namibian phosphatic sediments 

      Lumiste, Kaarel; Mänd, Kaarel; Bailey, Jake; Stüeken, Eva E.; Paiste, Kärt; Lang, Liisa; Sepp, Holar; Lepland, Aivo; Kirsimäe, Kalle (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-31)
      Modern phosphogenesis occurs on continental margins influenced by upwelling and high primary productivity. The formation of phosphatic sediments is coupled to global climate fluctuations, biological cycling of phosphorus and local redox conditions. Although the processes involved in phosphogenesis are well described, high-resolution data on the redox and stable isotope systematics in Recent in-situ ...

    • Heterogeneous REE + Y distribution in Early Paleozoic shelly phosphorites: Implications for enrichment mechanisms 

      Lumiste, Kaarel; Lang, Liisa; Paiste, Päärn; Lepland, Aivo; Kirsimäe, Kalle (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-27)
      Sedimentary phosphorites are important carriers of Rare Earth Elements and Yttrium (REE + Y). Primary biogenic and sedimentary apatite contain very low amounts of REE + Y and enrichment of these elements occurs during diagenesis. Although the influence of post-depositional processes on REE + Y concentrations in sedimentary phosphorites is well established, the processes controlling the degree of ...

    • Iron Isotopes Reveal a Benthic Iron Shuttle in the Palaeoproterozoic Zaonega Formation: Basinal Restriction, Euxinia, and the Effect on Global Palaeoredox Proxies 

      Mänd, Kaarel; Lalonde, Stefan V.; Paiste, Kärt; Thoby, Marie; Lumiste, Kaarel; Robbins, Leslie J.; Kreitsmann, Timmu; Romashkin, Alexander E.; Kirsimäe, Kalle; Lepland, Aivo; Konhauser, Kurt O. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-31)
      The Zaonega Formation in northwest Russia (~2.0 billion years old) is amongst the most complete successions that record the middle of the Palaeoproterozoic era. As such, geochemical data from the formation have played a central role in framing the debate over redox dynamics in the aftermath of the Great Oxidation Event (GOE). However, uncertainty over local redox conditions and the degree of ...

    • REE+Y uptake and diagenesis in Recent sedimentary apatites 

      Lumiste, Kaarel; Mänd, Kaarel; Bailey, Juke; Paiste, Päärn; Lang, Liisa; Lepland, Aivo; Kirsimäe, Kalle (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-30)
      Rare Earth Elements and Yttrium (REE+Y) distribution in authigenic phases are frequently used as proxies for reconstructing past seawater conditions. Sedimentary apatite precipitates near the sediment-water interface and is therefore capable of recording the REE+Y composition of the overlying water column. While the overprinting of primary REE+Y signal during late stage diagenesis is a widely known ...