An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification
An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification
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DOI：
10.1130/b31216.1
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发表时间：
2015-09-01
影响因子：
4.9
通讯作者：
Blomeier, Dierk P. G.
中科院分区：
文献类型：
--
作者：
Bond, David P. G.;Wignall, Paul B.;Blomeier, Dierk P. G.
有争议的卡皮塔尼亚（中二叠世，262 Ma）灭绝事件仅在赤道纬度已知，因此其全球范围尚未得到很好的解决。我们证明了北纬地区（斯匹次卑尔根）在二叠纪中晚期发生了两次严重的腕足动物灭绝，其间相隔一个恢复阶段。斯匹次卑尔根地层（属于Kapp Starostin组）的新时代定年，使用锶同位素和d(13)C趋势，并与格陵兰岛更准确的剖面进行比较，表明第一次危机发生在Capitanian。这一年龄分配表明，这次中二叠世大灭绝发生在高纬度地区。氧化还原指标（黄铁矿树状体和痕量金属）表明，北方森林危机与氧气消耗的加剧同时发生，暗示在灭绝情景中存在缺氧。北纬地带碳酸盐的广泛和几乎全部消失也表明了酸化在危机中的作用。在恢复期间，新的腕足类和双壳类动物与幸存者一起出现，软体动物的优势增加，导致了一个让人想起中生代早期组合的组合。随后的二叠纪末期大灭绝终止了二叠纪晚期的辐射。
The controversial Capitanian (Middle Permian, 262 Ma) extinction event is only known from equatorial latitudes, and consequently its global extent is poorly resolved. We demonstrate that there were two, severe extinctions amongst brachiopods in northern Boreal latitudes (Spitsbergen) in the Middle to Late Permian, separated by a recovery phase. New age dating of the Spitsbergen strata (belonging to the Kapp Starostin Formation), using strontium isotopes and d(13)C trends and comparison with better-dated sections in Greenland, suggests that the first crisis occurred in the Capitanian. This age assignment indicates that this Middle Permian extinction is manifested at higher latitudes. Redox proxies (pyrite framboids and trace metals) show that the Boreal crisis coincided with an intensification of oxygen depletion, implicating anoxia in the extinction scenario. The widespread and near-total loss of carbonates across the Boreal Realm also suggests a role for acidification in the crisis. The recovery interval saw the appearance of new brachiopod and bivalve taxa alongside survivors, and an increased mollusk dominance, resulting in an assemblage reminiscent of younger Mesozoic assemblages. The subsequent end-Permian mass extinction terminated this Late Permian radiation.