DOI: 10.5061/dryad.dfn2z35bq
title: Sponge silicon isotope analyses from Triassic–Jurassic boundary samples (Levanto and Malpaso, Perú) and individual spicule analyses on modern sponges (analyzed via SIMS)

description: 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.
description: 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
 &gt;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.
description: # Sponge silicon isotope analyses from Triassic–Jurassic boundary samples
 (Levanto and Malpaso, Perú) and individual spicule analyses on modern
 sponges (analyzed via SIMS)
 [https://doi.org/10.5061/dryad.dfn2z35bq](https://doi.org/10.5061/dryad.dfn2z35bq) ## Description of the data and file structure **Supplementary information.** This includes information about heat treating modern spicules and supplementary tables 1–3.  **Supplementary data tables 4–6.** 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 quantitative constraints on the global silicon cycle during the Mid-Mesozoic. In tables 4–6, each SIMS spot analysis is reported in ‰ relative to NBS28 and Caltech Rose Quartz with the spot's analytical uncertainty reported as its standard deviation (± 1 sigma (‰)). Analyses with &gt; 0.25‰ SD were removed and are not reported.  * **Supplementary Table 4.** Levanto sponge spicule silicon isotope data. Column 'Sample' refers to the sample name, which corresponds to the same samples as those used in Yager et al., 2017. The column 'Age (Ma)' refers to the sample age. The column 'Spicule #' refers to the spicule measured within an individual sample. * **Supplementary Table 5.** Malpaso sponge spicule silicon isotope data. * **Supplementary Table 6.** Modern sponge spicule silicon isotope data from sponges referred to in Table 1 of the supplementary material.  Yager, J. A., West, A. J., Trower, E. J., Fischer, W. W., Ritterbush, K., Rosas, S., Bottjer, D. J., Celestian, A. J., Berelson, W. M., & Corsetti, F. A. (n.d.). Evidence for Low Dissolved Silica in mid-Mesozoic Oceans. American Journal of Science, 324, 18. [https://doi.org/10.2475/001c.122691](https://doi.org/10.2475/001c.122691) Yager, J. A., West, A. J., Corsetti, F. A., Berelson, W. M., Rollins, N. E., Rosas, S., & Bottjer, D. J. (2017). Duration of and decoupling between carbon isotope excursions during the end-Triassic mass extinction and Central Atlantic Magmatic Province emplacement. *Earth and Planetary Science Letters*, *473*, 227–236. [https://doi.org/10.1016/j.epsl.2017.05.031](https://doi.org/10.1016/j.epsl.2017.05.031)