Sponge silicon isotope analyses from Triassic–Jurassic boundary samples (Levanto and Malpaso, Perú) and individual spicule analyses on modern sponges (analyzed via SIMS)

This dataset includes silicon isotope ratios measured on sponge spicules (δ30Si) from two sections spanning the Triassic–Jurassic boundary (Levanto and Malpaso, Perú). These data are reported in Yager et al., AJS to constrain dissolved silica in the ocean and provide some of the first quantitative constraints on the global silicon cycle during the Mid-Mesozoic.

Methods
Lithified sedimentary rock samples from Levanto and Malpaso, Perú were collected from outcrops and cut into thin sections. Each thin section was examined for the presence of siliceous sponge spicules. Samples with >5% sponge spicule material were cut for one-inch round thin sections for secondary ion mass spectrometry (SIMS) analyses (n = 4 from Levanto and n = 2 from Malpaso). We also mounted and measured modern spicules for SIMS analyses and report those here (n = 4), since typically the sponge silicon isotope proxy is measured using an ICP-MS.