[1] Poulton S W, Canfield D E. Ferruginous conditions: A dominant feature of the ocean through Earth's history J]. Elements, 2011, 7(2): 107-112.
[2] Gomez-Saez G V, Dittmar T, Holtappels M, et al. Sulfurization of dissolved organic matter in the anoxic water column of the Black Sea[J]. Science Advances, 2021, 7(25): eabf6199.
[3] Wang C Y, Dong Z T, Fu X H, et al. Origin and paleoenvironment of organic matter in the Wufeng–Longmaxi shales in the northeastern Sichuan Basin[J]. Energy Exploration & Exploitation, 2021, 39(1): 134-155.
[4] 何龙,王云鹏,陈多福. 四川盆地晚奥陶世有机碳、氮同位素异常及其古环境意义[J]. 地球化学,2021,50（6）：623-634.

He Long, Wang Yunpeng, Chen Duofu. Organic carbon and nitrogen isotopic anomalies during Late Ordovician in Sichuan Basin, and their implications for the paleoenvironment[J]. Geochemistry, 2021, 50(6): 623-634.
[5] Kump L R, Arthur M A. Interpreting carbon-isotope excursions: Carbonates and organic matter[J]. Chemical Geology, 1999, 161(1/2/3): 181-198.
[6] Brenchley P J, Carden G A, Hints L, et al. High-resolution stable isotope stratigraphy of Upper Ordovician sequences: Constraints on the timing of bioevents and environmental changes associated with mass extinction and glaciation[J]. GSA Bulletin, 2003, 115(1): 89-104.
[7] Jones D S, Fike D A. Dynamic sulfur and carbon cycling through the end-Ordovician extinction revealed by paired sulfate-pyrite δ34S[J]. Earth and Planetary Science Letters, 2013, 363: 144-155.
[8] Zhang T G, Shen Y N, Zhan R B, et al. Large perturbations of the carbon and sulfur cycle associated with the Late Ordovician mass extinction in South China[J]. Geology, 2009, 37(4): 299-302.
[9] Hammarlund E U, Dahl T W, Harper D A T, et al. A sulfidic driver for the end-Ordovician mass extinction[J]. Earth and Planetary Science Letters, 2012, 331-332: 128-139.
[10] Chen X, Rong J Y, Li Y, et al. Facies patterns and geography of the Yangtze region, South China, through the Ordovician and Silurian transition[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 2004, 204(3/4): 353-372.
[11] 陈旭, 戎嘉余, 樊隽轩, 等. 奥陶—志留系界线地层生物带的全球对比[J]. 古生物学报, 2000, 39（1）: 100-114.

Chen Xu, Rong Jiayu, Fan Junxuan, et al. A global correlation of biozones across the Ordovician-Silurian boundary[J]. Acta Palaeontologica Sinica, 2000, 39(1): 100-114.
[12] Canfield D E, Raiswell R, Westrich J T, et al. The use of chromium reduction in the analysis of reduced inorganic sulfur in sediments and shales[J]. Chemical Geology, 1986, 54(1/2): 149-155.
[13] Kurtz A C, Kump L R, Arthur M A, et al. Early Cenozoic decoupling of the global carbon and sulfur cycles[J]. Paleoceanography, 2003, 18(4): 1090.
[14] Gill B C, Lyons T W, Young S A, et al. Geochemical evidence for widespread euxinia in the later Cambrian ocean[J]. Nature, 2011, 469(7328): 80-83.
[15] Cooper R A, Sadler P M, Contributors, et al. Chapter 20–the Ordovician period[M]//Gradstein F M, Ogg J G, Schmitz M D, et al. The geologic time scale. Amsterdam: Elsevier, 2012: 489-523.
[16] Yan D T, Chen D Z, Wang Q C, et al. Geochemical changes across the Ordovician-Silurian transition on the Yangtze Platform, South China[J]. Science in China Series D: Earth Sciences, 2009, 52(1): 38-54.
[17] Liu Y, Li C, Algeo T J, et al. Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 463: 180-191.
[18] Kozik N P, Gill B C, Owens J D, et al. Geochemical records reveal protracted and differential marine redox change associated with Late Ordovician climate and mass extinctions[J]. AGU Advances, 2022, 3(1): e2021AV000563.
[19] Dong Z T, Wang Z T, Zhang W L, et al. Dynamic sulfur and carbon cycles related to microbial sulfate reduction and volcanic activity during the Hirnantian glaciation in the Upper Yangtze Basin, South China[J]. Frontiers in Earth Science, 2022, 10: 971031.
[20] Dong Z T, Wang Z T, Zhang W L, et al. Distribution characteristics and genesis of marine anoxic conditions in the southwest of the Upper Yangtze Basin during the Late Ordovician-Early Silurian, South China[J]. Frontiers in Earth Science, 2022, 10: 934488.