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首页> 外文期刊>Planetary and space science >From the LIPS of a serial killer: Endogenic retardation of biological evolution on unstable stagnant-lid planets
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From the LIPS of a serial killer: Endogenic retardation of biological evolution on unstable stagnant-lid planets

机译：从连续杀手的嘴唇：内源性延迟在不稳定的停滞盖行星上的生物学演变

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摘要

Geological data imply plate tectonics was not active on the Archaean Earth pre-2.5 Ga. Key arguments include: the absence from the Archaean rock record of ophiolites and high-pressure metamorphic rocks; the rarity of Archaean andesites and lahars; the absence of arc-like, source-metasomatic, trace element signatures in Archaean calcalkaline magmatic suites; and fundamental differences in overall structural style and constituent lithologies. Conversely, unstable stagnant-lid models better account for many features of Archaean geology. Thermomechanical models imply many unstable stagnant-lid planets would experience mobile-lid phases linked to periodic mantle overturns of 30-100 million years duration, separated by stable-lid phases lasting 100-300 My. Mantle overturn upwelling zones would be characterized by high magma fluxes that may have generated continental nuclei, and would have reworked and resurfaced tracts of pre-existing oceanic and continental lithosphere. Overturns would also have generated large-scale lateral mantle flow patterns that would have pushed against the sub-continental lithospheric mantle keels underlying continents, and so induced continental drift and orogenesis, allowing mobile-lid behaviour despite the absence of plate-boundary forces such as slab pull. Major resurfacing of Earth's surface during overturns would have heated the hydrosphere and atmosphere, with many negative impacts on biota. The high magmatic fluxes associated with mantle overturn events are likely to have induced periodic mass extinctions that may have retarded biological evolution on Earth. Evolutionary progress towards more complex metazoan organisms may only have been possible after the more efficient plate tectonic cooling system helped create a stabler, more temperate planet; although causal relationships remain uncertain. Did the start of a plate tectonic, mobile-lid cooling system on Earth gradually end (or moderate) mantle overturn behaviour? Or was the world-girdling plate tectonic system only allowed to begin because 'other factors' gradually acted to suppress mantle overturns during the Proterozoic? These 'other factors' include: secular decay of radioactive isotopes, scavenging of radioactive elements into continents, and shrinkage of the fertile lower mantle reservoir that fed early overturns. When overturn behaviour ended on Earth is also uncertain. The 2.1-1.9 Ga magmatic and tectonic pulse on Earth is plausibly interpreted as an Archaean-style mantle overturn, but more research is needed to determine whether the Large Igneous Provinces (LIPs) of the Meso- and Neo-Proterozoic are as well. It is predicted that Earth-sized exoplanets with surface water and chondritic mantle compositions will spend at least the first 2 Ga of their evolution as unstable stagnant-lid planets, with periodic overturns preventing evolution of complex metazoan organisms. Many such planets could remain trapped in this cooling mode, with only rare cases transitioning into the more efficient plate tectonic cooling mode. If correct, this greatly decreases the probability that complex metazoans are present elsewhere in the universe.
机译：地质数据意味着板构造没有在拱门地球前2.5 GA上活跃。关键论点包括：缺席眼镜岩和高压变质岩石;考古安地士和拉哈尔的罕见性;缺乏弧形，源代索源性，痕量元素签名在拱形考角型岩浆套件中;整体结构风格和组成岩性的基本差异。相反，不稳定的Stagnant-LID模型更好地占考古地质的许多特征。热机械模型意味着许多不稳定的停滞盖行星将经历与周期性地幔的移动盖阶段有关30-100万年的持续时间，通过稳定的阶段持续100-300我的持续时间。 Mantle翻转上升区的特征在于可能产生大陆核的高岩浆势态，并将重新制作和重新覆盖预先存在的海洋和大陆岩石圈。翻转还将产生大规模的横向地幔流动模式，这些流动模式将推动副大陆型岩石罩底座龙骨，因此诱导的欧洲漂移和oryOnesis，尽管诸如诸如的板边界力，但仍允许移动盖行为板坯拉。地球表面在翻转期间的主要重新铺设将加热水层和大气，对Biota有很多负面影响。与地幔翻转事件相关的高岩浆助熔剂可能诱导可能在地球上具有迟钝的生物进化的周期性群状灭绝。在更有效的板块构造冷却系统有助于创建稳定器，更温和的星球之后，才能实现更复杂的甲卓生体的进化进展。虽然因果关系仍然不确定。板块构造的开始，地球上的移动盖冷却系统逐渐结束（或中等）覆盖行为吗？或者是世界上围绕的板块构造系统，只允许开始因为“其他因素”逐渐被抑制在正常古代的地幔上倾覆？这些'其他因素'包括：放射性同位素的世俗衰减，放射性元素的清除进入大洲，肥沃的较低的地幔水库的收缩，喂养早期被推翻。当倾覆在地球上结束的行为也不确定时。 2.1-1.9 Ga Magmatic和地球上的构造脉冲是可享受的宗教般的地幔被倾覆的解释，但需要更多的研究来确定中间和新生交的大型火成省（嘴唇）也是如此。预测，具有地表水和软骨型搭腔组合物的地形外延凸片将至少将第一个2 GA的演变为不稳定的停滞盖行星，并且周期性翻转覆盖复杂的甲基生物的演变。许多这样的行星可以保持在这种冷却模式中，只有罕见的情况过渡到更有效的板构造冷却模式。如果是正确的，这大大降低了复杂的美唑诺斯在宇宙中其他地方存在的概率。

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