Thermal Evolution and Magmatic History of Venus

金星被称为地球的孪生兄弟，因为它们的质量和半径相似，但金星上的表面条件与地球上的有很大不同。炎热和稠密的大气层不允许液态水保持稳定，然而，过去的情况可能有所不同。金星和地球在其热化学史上的什么时候开始分离仍然存在争议，但人们普遍认为，岩浆活动在很大程度上塑造了金星的表面和内部，并且可能至今仍在进行。热异常的观测结果被认为是金星上加尼基峡谷地区最近火山活动的证据。金星快车上的VEM光谱仪记录的熔岩流数据表明，在几个缺乏表面风化的地方存在年轻的熔岩流。二氧化硫（一种在岩浆喷发时产生的火山气体）的变化已经在先锋金星和后来的金星快车的测量中被记录下来，并提供了一条额外的证据，证明金星上的岩浆过程仍然活跃。反过来，金星上可能正在进行的岩浆过程是了解金星内部的最直接窗口。它们提供了行星内部组成和动力学与地表地质之间的联系。在这个项目中，我们将进行熔化实验，建议金星组成和熔融参数化，将包括在地球动力学模型。后者将被用来模拟金星的热化学历史，并提供关于当今火山和构造活动水平的预测，以及金星内部和表面的化学非均匀性程度。我们这个项目的主要目标是调查成分对金星内部部分熔融的影响，并了解在存在挥发物（如S，CO2和Cl）的情况下，在金星表面添加和不添加水的化学不均匀性的地壳循环的后果。特别是，我们将调查的作用，水的形成tesserae是金星上最古老的地区，其组成已被建议类似于地球上的大陆地壳。我们的耦合实验数值模拟方法将提供一个显着的贡献，以提高我们的理解金星的岩浆历史。此外，这种方法可用于预测最近选定的欧空局的EnVision和NASA的VERITAS任务即将进行的测量。

Venus is referred to as the Earth’s twin because of their similar mass and radius, but the present-day surface conditions on Venus are significantly different than on Earth. The hot and dense atmosphere does not allow for liquid water to be stable, however, the situation might have been different in the past. At what point in their thermochemical history Venus and Earth started to diverge is still debated, but it is well accepted that magmatic activity has considerably shaped Venus’ surface and interior through time and may be still ongoing today. Observations of thermal anomalies have been proposed to suggest recent volcanic activity in the Ganiki Chasma region on Venus. Emissivity data recorded by the VEM spectrometer on board Venus Express suggest the presence of young lava flows at several locations that were found to lack surface weathering. Variations in SO2, a volcanic gas produced during magmatic eruptions, have been recorded in measurements of Pioneer Venus and later Venus Express, and provides an additional line of evidence that magmatic processes could still be active on Venus. In turn, magmatic processes that may be ongoing on Venus are the most direct window into the planet’s interior. They provide a link between the planet’s interior composition and dynamics and the surface geology. In this project we will perform melting experiments on proposed Venus compositions and derive melting parametrizations that will be included in a geodynamical model. The latter will be used to model the thermochemical history of Venus and to provide predictions about the present-day level of volcanic and tectonic activity, as well as the degree of chemical heterogeneitiy in the interior and at the surface of Venus. Our main objectives for this project are to investigate the effects of composition on partial melting in the interior of Venus and to understand what are the consequences of crustal recycling in the presence of volatiles such as S, CO2 and Cl with and without the addition of water for chemical heterogeneities at the surface of Venus. In particular, we will investigate the role of water for the formation of tesserae which are the oldest regions on Venus, whose composition has been suggested to resemble that of the continental crust on Earth.Our coupled experiments-numerical modeling approach will provide a significant contribution to improve our understanding of the magmatic history of Venus. Furthermore, such an approach can be used to make predictions for upcoming measurements for the recently selected ESA’s EnVision and NASA’s VERITAS missions.