Hydrothermal recycling of sedimentary ammonium into oceanic crust and the Archean ocean at 3.24 Ga

Abstract

The Archean ocean supported a diverse microbial ecosystem, yet studies suggest that seawater was largely depleted in many essential nutrients, including fixed nitrogen. This depletion was in part a consequence of inefficient nutrient recycling under anoxic conditions. Here, we show how hydrothermal fluids acted as a recycling mechanism for ammonium (NH4+) in the Archean ocean. We present elemental and stable isotope data for carbon, nitrogen, and sulfur from shales and hydrothermally altered volcanic rocks from the 3.24 Ga Panorama district in Western Australia. This suite documents the transfer of NH4+ from organic-rich sedimentary rocks into underlying sericitized dacite, similar to what is seen in hydrothermal systems today. On modern Earth, hydrothermal fluids that circulate through sediment packages are enriched in NH4+ to millimolar concentrations because they efficiently recycle organic-bound N. Our data show that a similar hydrothermal recycling process dates back to at least 3.24 Ga, and it may have resulted in localized centers of enhanced biological productivity around hydrothermal vents. Last, our data provide evidence that altered oceanic crust at 3.24 Ga was enriched in nitrogen, and, when subducted, it satisfies the elemental and isotopic source requirements for a low-N, but 15N-enriched, deep mantle nitrogen reservoir as sampled by mantle plumes.

Reconstructing Nitrogen Sources to Earth’s Earliest Biosphere at 3.7 Ga

“…To assess the degree of lab-derived contamination, pure minerals (quartz, plagioclase, orthoclase, biotite, muscovite, kaolinite) and baked silica sand were processed through the same rock crushing and 208290 6.33 2.37 7.95 3.5 45 4.1 2.03 3.21 3.8 0.52 1,290 0.07 0.12 16.4 330 1.4 8.1 2.02 0.234 0.6 47 7.7 18 76 208291 8.86 2.93 20.4 9.4 89 0.1* 4.75 3.58 9.1 1.42 1,290 0.02* 0.46 66.9 470 2.4 11.9 3.08 0.36 0.7 72 9.8 46 94 208292 9.23 1.47 29 9.3 97 0.1* 5.49 3.83 12.1 1.69 1,400 0.02* 0.35 71.5 490 1.7 12.3 3.44 0.387 0.7 78 9.8 54 119 208293 7.83 2.78 22.7 12.6 123 0.1* 4.51 2.34 9.1 1.86 1,720 0.07 1.44 101 440 2.7 12 2.52 0.349 0.7 75 9.5 54 115 208294 5.92 0.83 4.34 21.7 41 80.9 3.83 0.59 1.7 0.76 428 0.46 2.76 101.5 350 1 * = measurements were below detection limit and are reported as 0.5 × the limit of detection. decarbonation protocol and found to accumulate a maximum of 1 ppm N; some specimens lost N compared to a handcrushed aliquot due to the washing step and acid-treatment of the rock powder (Stüeken et al, 2021). Hence contamination in the laboratory is not a major contributor of N to the samples.…”

Nitrogenous Altered Volcanic Glasses as Targets for Mars Sample Return: Examples From Antarctica and Iceland

“…If so, the data presented in this paper for the Antarctic hyaloclastites could reflect transfer of this N by circulating hydrothermal fluids to produce the δ 15 Ν reported in this paper (cf. Stüeken, Boocock, et al., 2021; Stüeken, Gregory, et al., 2021).…”

“…Gunn and Warren (1962) also noted that Ferrar dolerites intruded and lie directly upon Beacon sandstone sediments that include many plant fossils. The initial hydrothermal fluid circulation induced by the primary magmatic phase and underlying intrusions, interacting with these intercalated sedimentary components, could have led to the mobilization of NH 4 + (see the discussion of similar scenarios by Bebout et al (2018), Stüeken, Boocock, et al (2021), andStüeken, Gregory, et al (2021). This NH 4 + could then have been both fixed during formation of secondary zeolites and smectites and exchanged with sorbed cations present in already crystallized secondary phases.…”

Black shales and mesozonal quartz vein‐hosted Au: The Truchas Syncline, Spain and the Harlech Dome, Wales, a comparative study

“…Hydrothermal systems are efficient in recycling NH 4 (Stüeken et al, 2021). The significance of NH 4 in gold mineralisation has been discussed for deposits in the Carlin trend, vein‐type epithermal precious metal deposits, Witwatersrand reefs, a wide range of OGDs, the auriferous orogenic belt of South Island, New Zealand and the contact aureole of intrusion‐related gold systems (Fu et al, 2014; Jia, 2002; Kydd & Levinson, 1986; Meyer & Ridgway, 1991; Pitcairn et al, 2005; Ridgway et al, 1990) with general agreement that nitrogen levels and isotopic values for mica and whole rock samples reflect inheritance from sedimentary kerogen.…”