Geological Testing of Global Warming Models on Venus

在地球上，人们越来越认识到，被称为大火成岩省（LIP）的巨大火山事件（高达数百万平方公里）是快速气候变化的主要驱动力，有时会导致大规模的灭绝（其中高达90%的生命被消灭）。 在金星上，一个主要的LIP式火山活动脉冲发生在大约7亿年前，释放了大量的二氧化碳。这导致了极端的温室效应，目前的地表温度为450摄氏度（是你烤箱的两倍），大气层的密度是地球的90倍，由96%的二氧化碳组成。因此，金星表面没有液态水，因此没有明显的水侵蚀。然而，最近有人提出，在这一超暖事件之前，金星的条件更像地球，甚至包括海洋和河流的存在，以及生命的潜力。 我建议，这个戏剧性的气候变化模型金星可以通过地质测绘（使用麦哲伦航天器雷达数据）的两种类型的单位进行评估：旧的单位称为tesserae，可以代表像加拿大地盾的岩石，和年轻的广泛的玄武岩熔岩流（类似于夏威夷），覆盖90%的金星。宇宙魔方可能是在全球变暖之前安放的，当时金星上可能有水侵蚀。我们的假设也是，金星上最早的玄武岩熔岩流也是在较冷（类似地球）的条件下侵位的，而后来的玄武岩流则是在更热的当前条件下侵位的。 我们的团队最近在镶嵌物中发现了水侵蚀的证据，与模型一致。这一发现表明，镶嵌物的地质历史可能比以前认为的要长得多，甚至可能可以追溯到40亿年前，就像地球上最早的岩石一样。我建议开展一项运动，系统地绘制镶嵌体（其侵蚀历史，线性结构和叠加的熔岩池），以帮助解开其漫长的地质历史。我还提出了一个系统的详细映射的最古老的火山平原，以确定过渡的气候从地球一样的不适合居住，通过确定单位表现出侵蚀被削减的单位表现出没有侵蚀。 我的研究将为金星上这种失控的温室气候变化提供地质限制，这将为地球上现代全球变暖的风险提供见解。我的研究将允许比较金星和地球的火山历史。考虑到金星早期类似地球的历史，一个明显的问题是为什么金星走了一条与地球不同的道路。一个可能的答案是，金星经历了多次火山活动，使温度超过了临界点。如果是这样的话，也许金星为地球的未来提供了一个视角。 本研究将培养三名硕士和两名博士生。

Geological Testing of Global Warming Models on Venus On Earth, there is growing recognition that huge volcanic events (up to millions of km3) known as Large Igneous Provinces (LIPs) are major drivers of rapid climate change sometimes leading to mass extinctions (where up to 90% of life was obliterated). On Venus, a major pulse of LIP-style volcanism occurred ~700 million years ago and released a massive volume of carbon dioxide CO2. This caused extreme greenhouse warming to a current surface temperature of 450oC (twice as hot as your oven), and an atmosphere 90 times as dense as that of the Earth and composed of composed of 96% CO2. As a consequence, there is no liquid water on the surface of Venus and therefore no significant water erosion. However, it has recently been proposed that prior to this hyper-warming event Venus had conditions that were more Earth-like, even including the presence of oceans and rivers, and the potential for life. I propose that this dramatic climate change model for Venus can be evaluated through geological mapping (using Magellan spacecraft radar data) of two types of units: older units called tesserae which could represent rocks like those of the Canadian shield, and younger widespread basaltic lava flows (similar to Hawaii) that cover 90% of Venus. Tesserae would have been emplaced prior to global warming at a time when there could have been water erosion on Venus. Our hypothesis is also that the earliest basaltic lava flows on Venus were also emplaced during cooler (Earth-like) conditions, while the later basaltic flows would have been emplaced under the much hotter current conditions. Our team has recently discovered evidence for water erosion in tesserae, consistent with the modelling. This discovery indicates that tesserae could have a much longer geological history than previously believed, maybe even extending back 4 billion years, like the earliest rocks on Earth. I propose a campaign of systematic mapping of tesserae (of their erosional history, linear structures and superimposed lava ponds) to help unravel their protracted geological history. I also propose a systematic detailed mapping of the oldest volcanic plains in order to identify the transition in climate from Earth-like to inhospitable, by identifying units exhibiting erosion being cut by units exhibiting no erosion. My research will provide geological constraints on this runaway greenhouse climate change on Venus that will provide insights into the risks of modern global warming on Earth. My research will allow comparison of the volcanic history of Venus with that of Earth. Given an early Earth-like history for Venus, the obvious question is why Venus took a different path than Earth. One possible answer is that Venus experienced multiple pulse of volcanism that increased temperature beyond a tipping point. If so perhaps Venus offers a perspective into Earth's future. This research will train three MSc and two PhD students.