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The chemical weathering of continental silicate rocks by bicarbonate and rainwater leads to dissolution of silicate rocks and their constituents into rivers and streams. As these silicate rocks chemically weather, CO2 is sequestered in the form of calcium carbonate. This process likely controls CO2 in the atmosphere on long timescales. As these silicate constituents are delivered to coastal deltas, there is an opportunity for secondary clay gels to form which expel CO2 towards the atmosphere while consuming alkalinity and cations from the ocean. This process, reverse weathering, thus works with forward chemical weathering to constrain CO2 in the atmosphere. Reverse weathering has yet to be well constrained in coastal regions, so silicon isotope analysis was performed to use delta silicon-30 as a proxy to track reverse weathering. In the Gulf of Papua New Guinea, analysis shows that all sample delta silicon-30 values fall outside of the range of physical mixing, meaning that reverse weathering has been confirmed in the Gulf of Papua. Future sediment analysis must be conducted to constrain the flux of CO2 that reverse weathering causes, but this work has yet to be completed.