Hg Isotopes and Enhanced Hg Concentration in the Meishan and Guryul Ravine Successions: Proxies for Volcanism Across the Permian-Triassic Boundary
نویسندگان
چکیده
High-resolution organic carbon isotope ( ? 13 C), Hg concentration and isotopes curves are presented for the Permian-Triassic boundary (PTB) sections at Guryul Ravine (India) Meishan D (China). The total (TOC)-normalized concentrations reveal more intense environmental changes Latest Permian Mass Extinction (LPME) earliest Triassic (ETME) horizons coinciding with major C shifts. To highlight palaeoredox conditions we used redox-sensitive elements Rare Earth Element distribution. At Meishan, three Hg/TOC spikes (I, II, III) observed. Spike I remains after normalization by aluminum (Al), but disappears when normalized sulfur (TS). III, base of Bed 26, corresponds excursions in Hg/TS Hg/Al curves, indicating a change paleoredox from anoxic/euxinic framboidal pyrite-bearing sediments (Bed 26) to oxygenated 27). Ravine, four were observed: clear spike 46, II pyrite-rich 49, III PTB, IV LPME horizon. Some these disappear TS or Al is applied. (oxic conditions), only curve (anoxic/euxinic), (oxic). In both sections, deposition was organic-matter bound, role sulfides being minor locally restricted horizons. Positive mass-independent fractionation (MIF) odd (odd-MIF) observed pre-LPME samples, negative values LPME–PTB interval, positive above ETME Most Hg-isotope patterns probably controlled bathymetry atmospheric Hg-bearing deposits. source can be attributed Siberian Traps Large Igneous Province (STLIP). LPME-PTB complex STLIP sills (Stage 2) intruded coal-bearing sediments. 202 Hg, mercury odd-MIF ? 201 patterns, 199 Hg–Hg plot compatible volcanic deposition. Our study shows strength ratios as paleoenvironmental proxy tool stratigraphic correlation.
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ژورنال
عنوان ژورنال: Frontiers in Earth Science
سال: 2021
ISSN: ['2296-6463']
DOI: https://doi.org/10.3389/feart.2021.651224