Isotopic signals from Callovian–Kimmeridgian (Middle–Upper Jurassic) belemnites and bulk organic carbon, Staffin Bay, Isle of Skye, Scotland
Isotopic signals from Callovian–Kimmeridgian (Middle–Upper Jurassic) belemnites and bulk organic carbon, Staffin Bay, Isle of Skye, Scotland
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DOI：
10.1144/0016-76492008-067
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发表时间：
2009-06
影响因子：
2.7
通讯作者：
Elizabeth V. Nunn;G. Price;M. Hart;K. Page;M. Leng
中科院分区：
文献类型：
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作者：
Elizabeth V. Nunn;G. Price;M. Hart;K. Page;M. Leng
摘要本文提供的稳定同位素资料是对以往中-晚侏罗世同位素研究的延伸和拓展。从苏格兰斯凯岛斯塔芬湾和斯塔芬页岩地层采集的钙辉石样品的氧同位素值与卡洛纪-基默里吉纪6.7-20.6°C的古温度一致。碳同位素数据是第一批中等分辨率的陆地δ13Corg（主要是化石木屑）和海洋δ13Ccarb（钙辉石）之间关系的研究之一，这些数据来自地质同期记录。斯塔芬湾资料显示了广泛的早至中牛津世正碳同位素偏移。偏移最大值出现在cordatum带（英国北方鹦鹉螺带），尽管高值持续存在于tenuiserratum带。海洋和陆地记录之间的对应关系表明了海洋-大气系统的强烈耦合，并表明总可交换碳库在这一时期受到了影响。在已发表的特提斯记录中发现的通常归因于甲烷释放的中牛津负碳同位素偏移在斯塔芬湾数据中没有记录，这可能表明特提斯偏移并不代表全球碳储量的波动，应该重新评估甲烷假设的真实性。补充资料：同位素和地球化学数据可在http://www.geolsoc.org.uk/SUP18339上获得。
Abstract: The stable isotope data presented here significantly extend and expand upon previous isotopic investigations of the Middle to Late Jurassic interval. The belemnite samples collected from the Staffin Bay and Staffin Shale formations from the Isle of Skye, Scotland, yielded oxygen isotope values consistent with Callovian–Kimmeridgian palaeotemperatures of 6.7–20.6 °C. The carbon isotope data comprise one of the first moderately high-resolution investigations of the relationship between terrestrial δ13Corg (predominantly fossil wood debris) and marine δ13Ccarb (belemnites) as derived from a geologically coeval record. The Staffin Bay data reveal a broad Early to Mid-Oxfordian positive carbon isotope excursion. The excursion maximum occurs in the cordatum Zone (British Boreal ammonite zonation), although high values persist into the tenuiserratum Zone. The correspondence between the marine and terrestrial records indicates a strong coupling of the ocean–atmosphere system and suggests that the total exchangeable carbon reservoir would have been affected at this time. The Mid-Oxfordian negative carbon isotope excursions identified in published Tethyan records and commonly attributed to methane release are not recorded in the Staffin Bay data, which may suggest that the Tethyan excursions do not represent fluctuations in the global carbon reservoir and that the fidelity of the methane hypothesis should be re-evaluated. Supplementary material: Isotopic and geochemical data are available at http://www.geolsoc.org.uk/SUP18339.