PALEOECOLOGICAL ANALYSIS OF BENTHIC RECOVERY AFTER THE LATE PERMIAN MASS EXTINCTION EVENT IN EASTERN LOMBARDY, ITALY
PALEOECOLOGICAL ANALYSIS OF BENTHIC RECOVERY AFTER THE LATE PERMIAN MASS EXTINCTION EVENT IN EASTERN LOMBARDY, ITALY
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DOI：
10.2110/palo.2017.079
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发表时间：
2018-03
期刊：
影响因子：
1.6
通讯作者：
W. Foster;S. Danise;G. Price;R. Twitchett
中科院分区：
文献类型：
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作者：
W. Foster;S. Danise;G. Price;R. Twitchett
摘要晚二叠世生物大灭绝是中生代最严重的生物危机，伴随着相关的环境变化，包括在浅水陆棚环境中缺氧和缺氧条件的扩张。据推测，波浪曝气促进了氧气输送到海底，在最浅的海洋环境中提供了一个“可居住区”，使底栖无脊椎动物在早三叠世期间得以生存和快速恢复。我们通过研究意大利下三叠统塞尔维诺组的岩石和化石记录来验证这一假设。我们还提供了第一条δ13Ccarb同位素曲线，并提供了新的地层学上重要化石的产出数据（即，参见Tirolites Pastanus），以改善Servino组的地层格架。塞尔维诺组的低多样性化石组合与其他西部古特提斯地区的化石组合相似。相分析表明，底栖无脊椎动物仅限于波浪曝气设置，支持拟议的“可居住区”的假设。然而，没有证据表明在斯帕斯期之前的“可居住区”迅速恢复，这可能表明额外的环境压力。在较低的Spathian Myophoria层成员，增加分类和功能丰富性，出现狭盐，直立类群，显着的营业额，并增加底栖生物组合的组成异质性表明显着的底栖生物恢复，这是由于减少环境压力。在晚期Spathian“上段”之前，生物扰动作用不发育，仅限于少数薄层位，但在“上段”中，生物扰动作用的强度和生物扰动岩石的比例增加。这种变化可归因于气候变冷和环境压力的相关减少。这上部Spathian恢复脉冲现在可以追溯到整个西部古特提斯，在近岸和深海（低于波底）设置。
Abstract The late Permian mass extinction was the most severe biotic crisis of the Phanerozoic, with associated environmental changes that included the expansion of hypoxic and anoxic conditions in shallow shelf settings. It has been hypothesized that wave aeration promoted oxygen transport to the seafloor providing a ‘habitable zone' in the shallowest marine environments that allowed the survival and rapid recovery of benthic invertebrates during the Early Triassic. We test this hypothesis by studying the rock and fossil records of the Lower Triassic Servino Formation, Italy. We also provide the first δ13Ccarb isotope curve, and present new occurrence data of stratigraphically important fossils (i.e., cf. Tirolites cassianus), to improve the stratigraphic framework of the Servino Formation. The low-diversity fossil assemblages of the Servino Formation have similar compositions to other western Paleotethyan localities. Facies analysis demonstrates that benthic invertebrates were restricted to wave-aerated settings, supporting the proposed ‘habitable zone' hypothesis. However, there is no evidence for rapid recovery in the ‘habitable zone' prior to the Spathian, which may indicate additional environmental stresses. In the lower Spathian Myophoria Beds Member, an increase in taxonomic and functional richness, the appearance of stenohaline, erect taxa, significant turnover, and increased heterogeneity in the composition of benthic assemblages indicate significant benthic recovery, which is attributed to reduced environmental stress. Prior to the late Spathian “Upper Member”, bioturbation is poorly developed and restricted to only a few thin horizons, but in the “Upper Member” the intensity of bioturbation and proportion of bioturbated rock increase. This change can be attributed to climatic cooling and a related decrease in environmental stress. This upper Spathian recovery pulse can now be traced across the western Paleotethys, in both nearshore and deep offshore (below wave base) settings.