The Tonian-Cryogenian transition in Northeastern Svalbard
The Tonian-Cryogenian transition in Northeastern Svalbard
复制标题
DOI：
10.1016/j.precamres.2017.12.010
复制
发表时间：
2017-12
影响因子：
3.8
通讯作者：
G. Halverson;M. Kunzmann;J. Strauss;A. Maloof
中科院分区：
文献类型：
--
作者：
G. Halverson;M. Kunzmann;J. Strauss;A. Maloof
斯瓦尔巴群岛东北部新元古代地层序列在记录新元古代生命、海水化学和古环境的演化方面具有独特的重要性。这一贡献的重点是地层和地球化学记录从晚托尼到开始Cryogenian冰川在Hecla Hoek系列，通知辩论的新元古代时间尺度的细分，下降到第一个雪球冰期的原因，和新元古代氧化的克里思。该层段以Akademikerbreen群最上部的Kinnvika段和Polabreen群最下部的Elbobreen组的Russøya段为代表。这些单元记录了东斯瓦尔巴特盆地长期稳定的Akademikerbreen碳酸盐台地的消亡。上Russøya成员保存了一个深负碳同位素异常，已被链接到低温冷却的开始机械。这种异常以前与苏格兰所谓的艾莱负碳同位素异常有关。在这里，我们提出了一个修订的相关性，在斯瓦尔巴群岛的最新Tonian部分与相等的年龄，但更好的日期在北方劳伦蒂亚层序地层学和碳，锶同位素化学地层学。这些相关性提供了一种手段，用于校准的Tonian-Cryogenian过渡间隔在斯瓦尔巴群岛，并建议，上Russøya负碳同位素异常显着早于Cryogenian冰川的开始，约。在上覆的冰成彼得罗夫布林段底部的不整合面下，有2000万年的缺失记录。这一异常可能是两个类似规模的晚托尼负碳同位素异常的老。
The Neoproterozoic stratigraphic succession in northeastern Svalbard is uniquely important in documenting the evolution of Neoproterozoic life, seawater chemistry, and paleoenvironments. This contribution focuses on the stratigraphic and geochemical records spanning from the late Tonian to the onset of Cryogenian glaciation in the Hecla Hoek Series, with the purpose of informing debates on the subdivision of the Neoproterozoic time scale, the cause of the descent into the first snowball ice age, and the tempo of Neoproterozoic oxygenation. This interval is represented by the Kinnvika Member of the uppermost Akademikerbreen Group and the Russøya Member of the Elbobreen Formation, lowermost Polarisbreen Group. These units record the demise of the long-lived, stable Akademikerbreen carbonate platform in the East Svalbard basin. The upper Russøya Member preserves a deep negative carbon isotope anomaly that has been linked mechanistically to the onset of Cryogenian cooling. This anomaly was previously correlated with the so-called Islay negative carbon isotope anomaly in Scotland. Here we propose a revised correlation of the latest Tonian section in Svalbard with equivalent-aged but better dated successions in northern Laurentia using sequence stratigraphy and carbon and strontium isotope chemostratigraphy. These correlations provide a means for calibrating the Tonian-Cryogenian transition interval in Svalbard and suggest that the upper Russøya negative carbon isotope anomaly significantly predates the onset of Cryogenian glaciation, with ca. 20 million years of missing record beneath the disconformity at the base of the overlying glaciogenic Petrovbreen Member. This anomaly may be the older of two late Tonian negative carbon isotope anomalies of similar magnitude.