Record of Albian to early Cenomanian environmental perturbation in the eastern sub-equatorial Pacific
Record of Albian to early Cenomanian environmental perturbation in the eastern sub-equatorial Pacific
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DOI：
10.1016/j.palaeo.2015.01.025
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
J. Navarro-Ramirez;S. Bodin;U. Heimhofer;A. Immenhauser
中科院分区：
文献类型：
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作者：
J. Navarro-Ramirez;S. Bodin;U. Heimhofer;A. Immenhauser
本文记录并讨论了来自秘鲁东太平洋赤道下的一条新的阿尔今-早塞诺曼世碳同位素（δ 13carband δ13Corg）曲线。给出了OAE1b组、OAE1c和OAE1d表达的化学地层证据。这个数据集是相关的，因为以前的工作强烈偏向于北美（西部内陆盆地）、欧洲（特提斯）和太平洋地区的研究地点。将秘鲁获得的碳同位素地层学与中太平洋和西太平洋、西大西洋和北特提斯和西特提斯的已发表剖面进行比较，发现总体上很一致，支持这里描述的同位素模式的全球性质。秘鲁的δ13C记录受到生物地层证据和保存完好的牡蛎壳的87sr /86Sr同位素地层的约束。此外，我们还记录了秘鲁西台地的异种动物经验-浅海混合碳酸盐-硅屑斜坡的发育及其相应的沉积相组合。该数据集用于阐明气候变化、营养供应和平台淹没之间复杂的相互作用，得出以下结论：(i)上阿普梯-下阿普梯主要沉积从硅质沉积为主转变为碳酸盐沉积，与基连水平的影响相一致；（ii）下阿普梯早期台地淹没与帕基耶尔水平的影响相一致；（iii）中阿普梯下部浅海碳酸盐生产的消亡与Leenhardt水平相一致，随后是中阿普梯中部浓缩沉积，在OAE1c开始之前，δ 13cbp值显著为负；上阿尔伯尼亚—下塞诺曼尼亚时期碳酸盐斜坡重新生成。这里显示的数据为未来记录秘鲁白垩纪中期的工作及其对东南次赤道太平洋古海洋学的影响奠定了基础。
The present paper documents and discusses a new Albian–early Cenomanian carbon isotope (δ13Ccarband δ13Corg) curve from the subequatorial Eastern Pacific in Peru. Chemostratigraphic evidences for the expression of the OAE1b set and for OAE1c and OAE1d are presented. This dataset is relevant inasmuch as previous work is strongly biased towards study sites in North America (Western Interior Basin), in Europe (Tethys) and the Pacific realm. A comparison of the carbon isotope stratigraphy obtained in Peru with published sections from the Central and Western Pacific, the Western Atlantic and Northern and Western Tethys reveals an overall good agreement supporting the global nature of the isotope patterns described here. The δ13C from Peru record is constrained by biostratigraphic evidence and87Sr/86Sr isotope stratigraphy using well-preserved oyster shells. Furthermore, we document the development of a heterozoan epeiric–neritic mixed carbonate–siliciclastic ramp in the Western Platform of Peru and its corresponding sedimentary facies associations. This dataset was used to elucidate the complex interplay of climatic changes, nutrient supply, and platform drowning, leading to the following conclusions: (i) an upper Aptian–lower Albian major change from siliciclastic-dominated to carbonate sedimentation coincided with the impact of the Kilian Level, (ii) a lower Albian incipient platform drowning linked to the impact of the Paquier Level, (iii) A lower middle Albian major demise of neritic carbonate production that coincides with the Leenhardt Level, followed by middle Albian condensed sedimentation that reports prominent negative values in δ13Ccarbprior to the onset of OAE1c and (iv) finally, renewed carbonate ramp production during the upper Albian–lower Cenomanian. The data shown here represent the foundation for future work documenting the mid-Cretaceous of Peru and its implications for the palaeoceanography of the SE subequatorial Pacific.