Late Guadalupian to Lopingian (Permian) carbon and strontium isotopic chemostratigraphy in the Abadeh section, central Iran
Late Guadalupian to Lopingian (Permian) carbon and strontium isotopic chemostratigraphy in the Abadeh section, central Iran
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伊朗中部阿巴代剖面晚瓜达卢普世至洛平世（二叠纪）碳和锶同位素化学地层学
DOI：
10.1016/j.gr.2012.10.012
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发表时间：
2013-07
影响因子：
6.1
通讯作者：
Chen, Xiao-zheng
中科院分区：
文献类型：
--
作者：
Liu, Xin-chun;Wang, Wei;Shen, Shu-zhong;Gorgij, Mohammad Nabi;Ye, Fa-cheng;Zhang, Yi-chun;Furuyama, Seishiro;Kano, Akihiro;Chen, Xiao-zheng
阿巴代剖面位于伊朗中部汉巴斯特河谷，暴露良好，长期以来一直是研究最广泛的剖面之一，因为其从下二叠统到下三叠统连续存在以碳酸盐为主的地层。然而，生物地层学以及与其他地区等效序列的相关性仍然存在争议。本文测量了基于散装碳酸盐样品的碳同位素偏移（δ13Ccarb）和锶同位素比（87Sr/86Sr），作为化学地层代理来估计阿巴德剖面洛平纪的三个不同年代地层边界，包括二叠纪-三叠纪事件（PTEB）、瓜达卢普阶-洛平阶（GLB）和乌家平阶-长兴阶边界（WCB）。这三个边界对于理解这个关键区间周围的海洋生物进化非常重要。根据 δ13C 偏移、87Sr/86Sr 的上升趋势和 0.7073 附近的值以及微生物岩层的产状，建议二叠纪-三叠纪事件边界（=梅山剖面的 25 层）位于主微生物岩层底部以下 -0.5m。根据轻微 δ13Ccarb 负耗损的位置，加上 87Sr/86Sr 的值在 0.7069 至 0.7070 之间及其上升趋势的起点，建议 GLB 位于 -46.5m，该值高于古生代 87Sr/86Sr 比值的最低值 0.7068。使用锶同位素比的局部加权回归散点图平滑器 (LOWESS) 对整个 Lopingian 剖面厚度与其高分辨率沉积年龄（预测年龄）之间的关系进行插值。根据负δ13C偏移和87Sr/86Sr比值0.7072，估计WCB位于6单元和7单元之间的岩性边界之上1m，远低于以前牙形刺生物地层学定义的边界，但与其他指示化石相似。该边界被投影为约。 87Sr/86Sr年龄投影模型中的254.6Ma与华南锆石U/Pb测年年龄接近。
The Abadeh section, well-exposed in the Hambast Valley in central Iran, has long been one of the most extensively studied sections because of its continuous carbonate-dominated strata from Lower Permian to Lower Triassic. However, biostratigraphy and correlation with the equivalent sequences in other regions remain controversial. In this paper both carbon isotope excursion (δ13Ccarb) and strontium isotope ratio (87Sr/86Sr) based on bulk carbonate samples have been measured to serve as chemostratigraphical proxies to estimate the three different chronostratigraphical boundaries in the Lopingian at the Abadeh section, including the Permian–Triassic Event (PTEB), the Guadalupian–Lopingian (GLB), and the Wuchiapingian–Changhsingian boundaries (WCB). These three boundaries are important for understanding the marine biological evolution around this critical interval. Based on the δ13C excursions, the rising trend of87Sr/86Sr and the value around 0.7073, and the occurrence of microbialite beds, the Permian–Triassic event boundary (=Bed 25 at the Meishan section) is suggested at −0.5m below the base of the main microbialite bed. The GLB is suggested at −46.5m based on the position of the minor δ13Ccarbnegative depletion, coupled with the values between 0.7069 and 0.7070 of87Sr/86Sr and its beginning point of the rising trend, which is above the lowest value 0.7068 of87Sr/86Sr ratio in the Paleozoic. The relationship between section thickness and their high-resolution depositional age (projecting age) is interpolated for the whole Lopingian using locally weighted regression scatter plot smoother (LOWESS) of strontium isotopic ratio. Based on the negative δ13C excursion and the value 0.7072 of87Sr/86Sr ratio, the WCB is estimated at 1m above the lithologic boundary between Unit 6 and Unit 7, much lower than the boundary defined by previous conodont biostratigraphy, but similar to other index fossils. This boundary is projected as ca. 254.6Ma in87Sr/86Sr-age projecting model and is close to zircon U/Pb dating age from South China.
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DOI：
10.2110/palo.2011.p11-058r
发表时间：
2012-02
期刊：
--
影响因子：
--
作者：
P. Wignall;D. Bond;J. Haas;Wei Wang;Haishui Jiang;X. Lai;D. Altıner;Stéphanie Védrine;Kinga Hips;N. Zajzon;Yadong Sun;R. Newton
通讯作者：
P. Wignall;D. Bond;J. Haas;Wei Wang;Haishui Jiang;X. Lai;D. Altıner;Stéphanie Védrine;Kinga Hips;N. Zajzon;Yadong Sun;R. Newton
影响因子：
3.9
作者：
A. Widerlund;P. Andersson
通讯作者：
A. Widerlund;P. Andersson
影响因子：
5.3
作者：
He, B;Xu, YG;Wang, Y
通讯作者：
Wang, Y
影响因子：
5.8
作者：
R. Twitchett;L. Krystyn;A. Baud;J. Wheeley;S. Richoz
通讯作者：
R. Twitchett;L. Krystyn;A. Baud;J. Wheeley;S. Richoz
影响因子：
56.9
作者：
D. Erwin
通讯作者：
D. Erwin