Improvement of the thallium isotope redox proxy within suboxic to anoxic sediments

Compiled data on trace metal concentrations in sediments and porewaters, Fe speciation in sediments, and sedimentary authigenic and lithogenic thallium isotopes across various marginal settings from the California, Mexico, and Peru margins. These cover various bottom water oxygen contents and local geochemical indicators of redox to better constrain thallium isotopes in low oxygen systems. Data indicate perrenially anoxic sites preserve accurate seawater thallium compositions, while sites deemed suboxic (manganous to ferruginous based on porewater concentrations) have an offset isotopic value. Oxic sections record the most isotopically positive values due to presence of Mn oxides.