The Paleocene-Eocene thermal maximum (PETM) in shallow-marine successions of the Adriatic carbonate platform (SW Slovenia)
The Paleocene-Eocene thermal maximum (PETM) in shallow-marine successions of the Adriatic carbonate platform (SW Slovenia)
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DOI：
10.1130/b30553.1
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发表时间：
2012-07
影响因子：
4.9
通讯作者：
J. Zamagni;M. Mutti;P. Ballato;A. Košir
中科院分区：
文献类型：
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作者：
J. Zamagni;M. Mutti;P. Ballato;A. Košir
古新世-始新世热峰是新生代最迅速和最极端的变暖事件之一。亚得里亚海碳酸盐台地的浅水地层剖面为了解古新世-始新世热极大期的性质及其对浅水生态系统的影响提供了难得的机会。我们使用碳和氧同位素地层学，结合详细的大型底栖有孔虫生物地层学，建立一个高分辨率的古气候记录的古新世始新世热最大。在古新世-始新世热峰期，块状岩石、基质和有孔虫的δ 13 C曲线出现显著的负偏移，分别为δ 13 C曲线的0.1 ‰-3‰、0.4 ‰和0.6 ‰。与开阔海记录相比，我们的浅海碳酸盐岩的δ 13 C记录强烈亏损，这可能是有机质氧化的结果，表明风化、径流和有机质通量的增强。伊勒底大型底栖有孔虫营业额详细记录的基础上高分辨率的相关性与碳同位素的偏移。营业额被描述为一个两步的过程，与第一步（早期Ilerdian）的特点是一个快速多样化的小alveolinids和nummulitids与弱成人二型性，可能是适应波动的古新世-始新世热最大营养水平，和第二步（中期Ilerdian）的特点是进一步具体的多样化，增加壳的大小，以及发达的成人二型性。在长期的生物过程控制的进化方案，我们认为，高海水温度可能刺激了早期的伊勒迪亚快速特定的多样化。总之，这些数据有助于阐明全球变暖的影响和浅水生态系统中的相关反馈，并通过推理，可以作为未来变化的评估模拟。
The Paleocene-Eocene thermal maximum represents one of the most rapid and extreme warming events in the Cenozoic. Shallow-water stratigraphic sections from the Adriatic carbonate platform offer a rare opportunity to learn about the nature of Paleocene-Eocene thermal maximum and the effects on shallow-water ecosystems. We use carbon and oxygen isotope stratigraphy, in conjunction with detailed larger benthic foraminiferal biostratigraphy, to establish a high-resolution paleoclimatic record for the Paleocene-Eocene thermal maximum. A prominent negative excursion in δ 13 C curves of bulk-rock (∼1‰–3‰), matrix (∼4‰), and foraminifera (∼6‰) is interpreted as the carbon isotope excursion during the Paleocene-Eocene thermal maximum. The strongly 13 C-depleted δ 13 C record of our shallow-marine carbonates compared to open-marine records could result from organic matter oxidation, suggesting intensified weathering, runoff, and organic matter flux. The Ilerdian larger benthic foraminiferal turnover is documented in detail based on high-resolution correlation with the carbon isotopic excursion. The turnover is described as a two-step process, with the first step (early Ilerdian) marked by a rapid diversification of small alveolinids and nummulitids with weak adult dimorphism, possibly as adaptations to fluctuating Paleocene-Eocene thermal maximum nutrient levels, and a second step (middle Ilerdian) characterized by a further specific diversification, increase of shell size, and well-developed adult dimorphism. Within an evolutionary scheme controlled by long-term biological processes, we argue that high seawater temperatures could have stimulated the early Ilerdian rapid specific diversification. Together, these data help elucidate the effects of global warming and associated feedbacks in shallow-water ecosystems, and by inference, could serve as an assessment analog for future changes.