Response of calcareous nannoplankton to the Paleocene–Eocene Thermal Maximum in the Paratethys Seaway (Tarim Basin, West China)
Response of calcareous nannoplankton to the Paleocene–Eocene Thermal Maximum in the Paratethys Seaway (Tarim Basin, West China)
复制标题
DOI：
10.1016/j.gloplacha.2022.103918
复制
发表时间：
2022-08
影响因子：
3.9
通讯作者：
Yasu Wang;Ying Cui;Hong Su;Jingxin Jiang;Yang Wang;Zhilin Yang;Xiumian Hu;Shijun Jiang
中科院分区：
文献类型：
--
作者：
Yasu Wang;Ying Cui;Hong Su;Jingxin Jiang;Yang Wang;Zhilin Yang;Xiumian Hu;Shijun Jiang
古新世-始新世最高温度(PETM)是一种发生在5600万年前的快速全球变暖，被广泛认为是人类排放二氧化碳导致的持续变暖的古老类比。中国西北部塔里木盆地保存完整、连续的古近纪浅海地层保存完好，是研究帕拉提斯海道古环境变化的理想场所。迄今为止，塔里木盆地PETM段还没有进行高分辨率的钙质超微化石生物地层学研究。库子贡苏地区祁木根组露头样品中含有丰富、保存较好的钙质超微化石，建立了高分辨率生物地层格架。共观察到钙质超微化石33属73种，其中优势种为绿球藻属(Coccolios Pelagicus)、变种(Toweius)、金龟子属(Pontosphaera Exilis)和微石藻(Micrantholius Flos)。这5种钙质超微化石数据有助于识别NP6至NP10带。整个剖面中常见的浅水类群(微体石属)表明，库子贡苏剖面的沉积环境是从中到外的浅海环境。本文报道了“游动类群”(Coccolisus Bownii，Discoaster araneus，D.acutus，Rhomboasterspp.)的地层分布。与δ13C和δ180Carb的负漂移范围一致，表明这些“漂移类群”是识别Paratthys海道中是否存在PETm的微古生物学标志。在PETM期间，超微化石的保存恶化和丰度极低，以及接近于零的wt%CaCO3值表明，海洋酸化发生在Paratthys Seaway的浅水区。此外，作为一种高生产力指标的新基亚兹鱼种群数量显著增加，表明表层海洋生产力有所增加。更高的初级生产力可能是由加强的大陆风化作用引发的，通过河流径流提供更多的养分。
The Paleocene-Eocene Thermal Maximum (PETM) was a rapid global warming occurred 56 million years ago and has been widely viewed as an ancient analogue to the ongoing warming driven by anthropogenic CO2emissions. The complete and continuous Paleogene shallow marine strata well preserved and outcropped in the Tarim Basin, northwestern China are ideal to study the paleoenvironmental change of the Paratethys Seaway during the PETM. To date, no high-resolution calcareous nannofossil biostratigraphy has been performed for the PETM interval in the Tarim Basin. Outcrop samples taken from the Qimugen Formation in the Kuzigongsu section contain abundant, moderately well preserved calcareous nannofossils, allowing for the establishment of a high-resolution biostratigraphic framework. Overall, 73 species of calcareous nannofossils from 33 genera were observed, with the dominant species includingCoccolithus pelagicus, variousToweiusspecies,Pontosphaera exilis, andMicrantholithus flos.The five calcareous nannofossil datums allow for the recognization of nannofossil Zone NP6 through Zone NP10. The common occurrence of shallow-water taxa (Micrantholithus) throughout the section suggests a middle to outer neritic setting as the depositional environment of the Kuzigongsu section. The stratigraphic distribution of “excursion taxa” (Coccolithus bownii, Discoaster araneus,D. acutus, Rhomboasterspp.) is consistent with the range of negative excursions in δ13Ccarband δ18Ocarb, indicating that these “excursion taxa” are micropaleontological markers for identifying the presence of the PETM in the Paratethys Seaway. During the PETM, the deteriorated preservation and extremely low abundance of nannofossils and near-zero wt% CaCO3values suggest that ocean acidification occurred in the shallow water of the Paratethys Seaway. In addition, a significant increase in the speciesNeochiastozygus junctus, which is a high productivity indicator suggests increased surface ocean productivity. Higher primary productivity may be triggered by enhanced continental weathering delivering increased nutrient through river runoff.