Bekker dating rise atmospheric oxygen
In the modern ocean, ~80 to 90% of primary productivity gets remineralized in the photic zone (upper, ~200 m; fig.S1), with most of the remainder being oxidized at depth or in marine sediments ().Multiple proxies have been used to reconstruct P levels, including the P content of iron (Fe) oxide–rich sedimentary rocks ().However, these models have not accounted for potential “upstream” throttles that could have kept P concentrations low without any influence of Fe scavenging.Only a very small percentage (≪1%) of net primary productivity (and its associated P) escapes remineralization and is ultimately buried in marine sediments.
In Lübeck, for example, Brick Renaissance is clearly recognisable in buildings equipped with terracotta reliefs by the artist Statius von Düren, who was also active at Schwerin (Schwerin Castle) and Wismar (Fürstenhof).
The presence of rounded pebbles of sideritic iron formation at the base of the Rooihoogte Formation and an extensive and thick ironstone layer consisting of haematitic pisolites and oölites in the upper Timeball Hill Formation indicate that atmospheric oxygen rose significantly, perhaps for the first time, during the deposition of the Rooihoogte and Timeball Hill formations.
These units were deposited between what are probably the second and third of the three Palaeoproterozoic glacial events.
We propose that the size of the marine phosphorus reservoir was instead constrained by muted liberation of phosphorus during the remineralization of biomass.