A Carboniferous apex for the late Paleozoic icehouse
A Carboniferous apex for the late Paleozoic icehouse
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晚古生代冰室的石炭纪顶点
DOI：
10.1144/sp535-2022-256
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Iannuzzi, R.
中科院分区：
文献类型：
--
作者：
Griffis, N.;Mundil, R.;Montañez, I.;Le Heron, D.;Dietrich, P.;Iannuzzi, R.
冰室气候系统发生在地球历史的一个简短的部分，构成c。25%的古生代记录。晚古生代冰期（LPIA）是中生代最极端和持续时间最长的冰期，其特征是剧烈的大陆规模冰期，其间间隔着小于10 6年的冰极小期或无冰期。冈瓦纳南部巴拉那和卡拉哈里盆地的晚古生代冰川形成记录形成了这一冰川作用的最大，保存最完好和校准良好的记录之一。在石炭纪，巴拉那盆地和卡拉哈里盆地的东部和南部边缘的特点是冰下条件，大陆和高地冰川的证据。在最新的石炭纪，这些盆地从冰下水库过渡到无冰或“冰远端”的条件证明了广泛的沉积海洋沉积物并列冰下底形。高精度的U-Pb锆石化学磨蚀热电离质谱地质年代学的限制，从火山灰沉积在冰消的海洋黑色页岩的卡拉哈里盆地和河流和煤炭的继承，覆盖在巴拉那盆地的海洋沉积，表明在这些地区的冰下的证据被限制在石炭纪。在这些地区的冰的损失是一致的晚石炭世峰值二氧化碳分压和广泛的海洋缺氧在晚石炭世。渗透退缩的冰川盆地设置，尽管早二叠世pCO 2的最低点，突出了短期扰动的影响，长期的CO 2记录，并建议冰阈值已越过在最新的石炭纪。LPIA中温室气体的决定性驱动因素，例如丰富和持续的火山活动或海洋施肥驱动的生物泵增加，在此期间尚未解决。最后，高纬度LPIA记录的石炭纪顶点与低纬度热带地区的观测结果不一致，其中提出了早二叠世的峰值。
Icehouse climate systems occur across an abbreviated portion of Earth history, constituting c. 25% of the Phanerozoic record. The Late Paleozoic Ice Age (LPIA) was the most extreme and longest lasting glaciation of the Phanerozoic and is characterized by periods of acute continental-scale glaciation, separated by periods of ice minima or ice-free conditions on the order of< 10 6 years. The late Paleozoic glaciogenic record of the Paraná and Kalahari basins of southern Gondwana form one of the largest, best-preserved and well-calibrated records of this glaciation. In the Carboniferous, the eastern and southern margins of the Paraná Basin and the Kalahari Basin were characterized by subglacial conditions, with evidence for continental and upland glaciers. In the latest Carboniferous, these basins transitioned from subglacial reservoirs to ice-free or ‘ice distal ‘conditions evidenced by the widespread deposition of marine deposits juxtaposed on subglacial bedforms. High-precision U–Pb zircon chemical abrasion thermal ionization mass spectrometry geochronological constraints from volcanic ash deposits in the deglacial marine black shales of the Kalahari Basin and from fluvial and coal successions, which overlie marine deposits in the Paraná Basin, indicate subglacial evidence in these regions is constrained to the Carboniferous. The loss of ice in these regions is congruent with a late Carboniferous peak in pCO 2 and widespread marine anoxia in the late Carboniferous. The permeant retreat of glaciers in basinal settings, despite an early Permian pCO 2 nadir, highlights the influence of short-term perturbations on the longer-term CO 2 record and suggests an ice threshold had been crossed in the latest Carboniferous. A definitive driver for greenhouse gases in the LPIA, such as abundant and sustained volcanic activity or an increased biological pump driven by ocean fertilization, is unresolved for this period. Lastly, the proposed Carboniferous apex for the high-latitude LPIA record is incongruent with observations from the low-latitude tropics where an early Permian peak is proposed.