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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Isotopic evidence bearing on Late Triassic extinction events, Queen Charlotte Islands, British Columbia, and implications for the duration and cause of the Triassic/Jurassic mass extinction
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Isotopic evidence bearing on Late Triassic extinction events, Queen Charlotte Islands, British Columbia, and implications for the duration and cause of the Triassic/Jurassic mass extinction

机译：有关不列颠哥伦比亚夏洛特皇后群岛三叠纪晚期灭绝事件的同位素证据，及其对三叠纪/侏罗纪大规模灭绝的持续时间和成因的影响

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摘要

Stable isotope analyses of Late Triassic to earliest Jurassic strata from Kennecott Point in the Queen Charlotte Islands, British Columbia, Canada shows the presence of two distinct and different organic carbon isotope anomalies at the Norian/Rhaetian and Rhaetian/Hettangian (=Triassic/Jurassic) stage boundaries. At the older of these boundaries, which is marked by the disappearance of the bivalve Monotis, the isotope record shows a series of short-lived positive excursions toward heavier values. Strata approaching this boundary show evidence of increasing anoxia. At the higher boundary, marked by the disappearance of the last remaining Triassic ammonites and over 50 species of radiolarians, the isotopic pattern consists of a series of short duration negative anomalies. The two events, separated by the duration of the Rhaetian age, comprise the end-Triassic mass extinction. While there is no definitive evidence as to cause, the isotopic record does not appear similar to that of the impact-caused Cretaceous/Tertiary boundary extinction.
机译：从加拿大不列颠哥伦比亚省夏洛特皇后群岛肯纳科特点的晚三叠世到最早的侏罗纪地层的稳定同位素分析表明，在诺里安/拉脱天和拉赫蒂安/黑塘阶（=三叠纪/侏罗纪）存在两个截然不同的有机碳同位素异常阶段边界。在这些边界中的较旧处（以双壳类Monotis的消失为标志），同位素记录显示了一系列对较重值的短暂正向偏移。接近该边界的地层显示出缺氧增加的证据。在较高的边界处，同位素模式由一系列短时间的负异常组成，其特征是最后剩下的三叠纪铵盐和超过50种放射虫消失。由Rhaetian时期的持续时间分隔的两个事件包括三叠纪末期生物灭绝。尽管没有确定的原因证据，但同位素记录似乎与因碰撞造成的白垩纪/第三纪界灭绝的记录相似。

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