Intercontinental correlation of organic carbon and carbonate stable isotope records: evidence of climate and sea-level change during the Turonian (Cretaceous)
Intercontinental correlation of organic carbon and carbonate stable isotope records: evidence of climate and sea-level change during the Turonian (Cretaceous)
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DOI：
10.1002/dep2.6
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发表时间：
2015-12-01
影响因子：
2.4
通讯作者：
Laurin, Jiri
中科院分区：
文献类型：
--
作者：
Jarvis, Ian;Trabucho-Alexandre, Joao;Laurin, Jiri
本文报道了捷克共和国波希米亚白垩纪盆地中部一个扩大的上白垩统（Turonian-Coniacian）半远洋层序的碳（delta C-13（org），delta C-13（carb））和氧（delta O-18（carb））同位素记录。地球物理测井、生物地层学和稳定碳同位素化学地层学提供了高分辨率的地层格架。三角洲C-13（碳水化合物）和三角洲C-13（org）的配置文件进行了比较，并与欧洲，北美和日本公布的同时代的海洋和非海洋同位素记录的时间序列相关。所有以前命名的Turonian碳同位素事件都在不同相、盆地和大陆的多个剖面之间以高分辨率进行了识别和对比。使用碳酸盐和有机质的碳同位素化学地层学的可行性，提高地层分辨率，放置阶段的边界，并为洲际对比证明，但锚定的时间序列，使用生物地层数据是必不可少的。一个早期到中期Turonian热最大值其次是同步事件的阶梯式冷却整个欧洲在中期到晚期Turonian散装碳酸盐和腕足类壳三角洲O-18（碳水化合物）的数据，以及大型底栖动物组合的分布和组成的区域变化证明。在欧洲的晚Turonian冷相是一致的长期海平面下降的时期，与显着的水团重组发生在中晚Turonian最大低位。三角洲C-13（三角洲C-13（carb）-三角洲C-13（org））的下降趋势与两个主要的冷却脉冲相一致，表明pCO（2）下降伴随着冷却，但在波希米亚盆地研究剖面的低碳酸盐沉积物中，由于三角洲C-13（carb）记录的成岩叠加，成对碳同位素作为高分辨率pCO（2）代用品的使用受到了影响。碳同位素化学地层学被证实是检验和完善洲际和海陆对比的有力工具。
Carbon (delta C-13(org), delta C-13(carb)) and oxygen (delta O-18(carb)) isotope records are presented for an expanded Upper Cretaceous (Turonian-Coniacian) hemipelagic succession cored in the central Bohemian Cretaceous Basin, Czech Republic. Geophysical logs, biostratigraphy and stable carbon isotope chemostratigraphy provide a high-resolution stratigraphic framework. The delta C-13(carb) and delta C-13(org) profiles are compared, and the time series correlated with published coeval marine and non-marine isotope records from Europe, North America and Japan. All previously named Turonian carbon isotope events are identified and correlated at high-resolution between multiple sections, in different facies, basins and continents. The viability of using both carbonate and organic matter carbon isotope chemostratigraphy for improved stratigraphic resolution, for placing stage boundaries, and for intercontinental correlation is demonstrated, but anchoring the time series using biostratigraphic data is essential. An Early to Middle Turonian thermal maximum followed by a synchronous episode of stepped cooling throughout Europe during the Middle to Late Turonian is evidenced by bulk carbonate and brachiopod shell delta O-18(carb) data, and regional changes in the distribution and composition of macrofaunal assemblages. The Late Turonian Cool Phase in Europe was coincident with a period of long-term sea-level fall, with significant water-mass reorganization occurring during the mid-Late Turonian maximum lowstand. Falling Delta C-13 (delta C-13(carb) - delta C-13(org)) trends coincident with two major cooling pulses, point to pCO(2) drawdown accompanying cooling, but the use of paired carbon isotopes as a high-resolution pCO(2) proxy is compromised in the low-carbonate sediments of the Bohemian Basin study section by diagenetic overprinting of the delta C-13(carb) record. Carbon isotope chemostratigraphy is confirmed as a powerful tool for testing and refining intercontinental and marine to terrestrial correlations.