Abstract Formation and subsequent burial of authigenic phases have been recognized as a key process removing silicon from the ocean. However, the effect of authigenic phase formation on the isotopic mass balance of silicon in the ocean is not clear. Here, we constrain the apparent silicon isotope (δ30Si) fractionation associated with early diagenesis by measuring δ30Si signatures of pore fluids and authigenic phases in a South Atlantic sediment core. The δ30Si offsets between authigenic phases and pore fluids vary between â2.9 and â0.4â°, supporting a substantial negative δ30Si fractionation during early diagenesis. The variable apparent δ30Si fractionation covaries with the amount of sedimentary lithogenic materials and may be attributable to the associated kinetic effects. Overall, our data show that authigenic phases buried along with their precursor phases preferentially remove isotopically light silicon from the ocean, with implications for the isotopic mass balance of the marine silicon cycle.
Observations from the Little Bunker
Last updated: August 18, 2025 04:13 PM
Atmospheric COâ
425.4 ppm
+18.4
ppm/year
Atmospheric CHâ
1934.91 ppb
+9.11
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year