Fig. 3: Fe speciation-TOC-δ34Spyr systematics.
From: Sedimentary pyrite sulfur isotopes track the local dynamics of the Peruvian oxygen minimum zone
a Cross plot of the ratio of pyrite Fe to highly reactive Fe (Fepyr/FeHR) against highly reactive Fe to total Fe (FeHR/FeT) in sediment−water interface (0–1 cmbsf; stars), core-top28,44 (<50 cmbsf; triangles) and buried28,44 (>50 cmbsf; circles) samples. Horizontal and vertical lines indicate the proposed boundaries for distinguishing euxinic from ferruginous and oxic water columns43,69, where solid lines are at Fepyr/FeHR and FeHR/FeT recommended on the basis of modern environments, and dashed lines are suggested boundaries for ancient sediments. b δ34Spyr vs. TOC for core-top51 and buried (this study) samples. Dotted lines represent the trendlines observed between Intra-OMZ core-top and SWI δ34Spyr values and TOC (orange) and down-core δ34Spyr values and TOC (green). Samples located within the upper SMTZ are outlined in dotted black. Filled symbols represent cores located within the OMZ, whereas open symbols represent cores outside the OMZ.
