The Pliensbachian-Toarcian (Early Jurassic) extinction, a global multi-phased event
The Pliensbachian-Toarcian (Early Jurassic) extinction, a global multi-phased event
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DOI：
10.1016/j.palaeo.2013.05.010
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发表时间：
2013-09-15
影响因子：
3
通讯作者：
Groecke, Darren R.
中科院分区：
文献类型：
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作者：
Caruthers, Andrew H.;Smith, Paul L.;Groecke, Darren R.
在早侏罗世的普林斯巴奇期-托阿尔期期间，发生了一次著名的二级海洋灭绝，在种和属水平上都可以观察到。来自整个欧洲和北极部分地区的菊石多样性数据表明，这次灭绝可能是多阶段的，多样性在六个不同的时间间隔内下降。下降的主要阶段开始于普林斯巴阶-托阿尔阶边界，并延伸至下托阿尔阶，达到与特努古斯塔图姆/蛇形带边界相关的水平。迄今为止，只有灭绝的主要阶段被证明具有全球范围并影响多个分类群。这种多阶段的灭绝归因于与火山温室情景相关的区域和全球控制机制，该情景将卡鲁-费拉尔大型火成岩省（LIP）的喷发与全球变暖和大规模灭绝联系起来。我们将北美西部普林斯巴赫期-托阿尔期序列中菊石和有孔虫物种的地层范围与欧洲和部分地区的记录进行了比较。 北极，以测试多个灭绝阶段的地理范围。我们的结果显示了与欧洲所认识到的物种水平下降的六个区间：I) 下普林斯巴阶中部（怀特韦西中部 - 弗雷博迪带中部），2) 上普林斯巴阶中部（上库纳埃 - 下卡洛滕斯带），3) 普林斯巴赫阶/福阿尔阶边界进入下托阿尔阶（上卡洛滕斯 - 中卡洛滕斯带），4) 中部 Toarcian（上Planulata-下Crassicosta带），5）上中-下上Toarcian（中Crassicosta-Hillebrandti带）和6）上Toarcian（下Yakounensis带）。在三个独立的海洋盆地（古太平洋，古北极和特提斯洋）中至少两个分类群中认识到这一多阶段事件，极大地扩展了已知的 这一多阶段事件的地理范围，并主张建立一个覆盖全球的控制机制。关于火山温室情景，我们的研究表明，六个灭绝脉冲中有四个发生在卡鲁岩浆作用的主阶段。早普林斯巴赫世的衰落以前被认为与该事件无关，但它发生在卡鲁岩浆活动开始的误差范围内，而晚托阿尔世的衰落与岩浆作用的后期阶段一致。这些观测结果将这一多阶段灭绝事件的已知持续时间延长至早期普林斯巴奇期，并支持火山温室情景，特别是卡鲁-费拉尔 LIP 的喷发，作为推动普林斯巴奇期-托阿尔奇期多阶段灭绝的重要因素。 (C) 2013 Elsevier B.V. 保留所有权利。
During the Pliensbachian-Toarcian interval of the Early Jurassic, there is a well-known second order marine extinction that is observable at the species and genus levels. Ammonite diversity data from successions throughout Europe and parts of the Arctic suggest that this extinction may have been multi-phased with diversity declining over six separate intervals. The main-phase of decline begins at the Pliensbachian-Toarcian boundary and extends into the Lower Toarcian, to a level that is correlative with the Tenuicostatum/Serpentinum Zone boundary. To date, only the main-phase of extinction has been demonstrated as being global in extent and affecting multiple taxonomic groups. This multi-phased extinction has been attributed to regional and global controlling mechanisms that are associated with the Volcanic Greenhouse Scenario which links the eruption of the Karoo-Ferrar large igneous province (LIP) to global warming and mass extinction.We compare stratigraphic ranges of ammonite and foraminiferal species in Pliensbachian-Toarcian successions of western North America to the record in Europe and parts of the Arctic in order to test the geographic extent of the multiple phases of extinction. Our results show six intervals of species level decline that correlate with those recognized in Europe: I) middle of the Lower Pliensbachian (middle Whiteavesi-middle Freboldi Zones), 2) middle of the Upper Pliensbachian (upper Kunae-lower Carlottense Zone), 3) Pliensbachian/Foarcian boundary into the Lower Toarcian (upper Carlottense-middle Kanense Zones), 4) Middle Toarcian (upper Planulata-lower Crassicosta Zones), 5) upper Middle-lower Upper Toarcian (middle Crassicosta-Hillebrandti Zones) and 6) Upper Toarcian (lower Yakounensis Zone).Recognition of this multi-phased event in three separate ocean basins (paleo Pacific, paleo Arctic, and Tethys Oceans), in at least two taxonomic groups, greatly expands the known geographic extent of this multi-phased event and argues for a controlling mechanism that is global in its reach. In relation to the Volcanic Greenhouse Scenario, our study shows that four of the six pulses of extinction occur within the main-phase of Karoo magmatism. The decline in the Early Pliensbachian, previously thought to be separate from this event, occurs within error range of the onset of Karoo magmatism and the decline in the Late Toarcian coincides with the later stages of magmatism. These observations extend the known duration of this multi-phased extinction event to the Early Pliensbachian and support the Volcanic Greenhouse Scenario, specifically the eruption of the Karoo-Ferrar LIP, as a preeminent factor driving the multi-phased extinction of the Pliensbachian-Toarcian. (C) 2013 Elsevier B.V. All rights reserved.