Laboratory analogues of black smoker hydrothermal vent mineral facies relevant to planetary science

Hydrothermal systems form when mineral rich vent fluid is released through cracks in the ocean crust, causing a precipitation reaction. These systems are currently, or were previously, present on a variety of planetary bodies in this Solar System, including Earth, Mars and possibly Europa and Enceladus. Hydrothermal systems support diverse ecosystems and provide insight into the origins of life. They contain a number of gradients (e.g., temperature, pH, mineralogy), making the environment a complex system to untangle. Deep ocean hydrothermal vents are difficult to access, requiring ocean cruises, and limited monitoring opportunities. For these reasons, laboratory analogue studies can provide accessible ways to test the primary controls on hydrothermal vent formation, in systems where variables can be better controlled. Past and future planetary missions, like Cassini and Europa Clipper, contain instrument suites capable of detecting organic materials and other environmental data to better determine the ability of a planetary environment to contain life. Due to the importance of hydrothermal environments for future space-flight missions, it is important to consider geochemical conditions in how reactions would proceed, particularly regarding hydrothermal chimney growth. This project explores the growth of laboratory analogues of hydrothermal chimneys, focusing on the mineralogical gradient from interior to exterior and how chemical composition affects the morphology of the chimney. In these experiments, chimneys with different elemental compositions (namely, sulfide rich and sulfide poor iron chimneys) were grown via an injection method to explore how chimneys grow in an environment devoid of life. A primary challenge in these studies is maintaining anoxic conditions; in this paper we explore how these challenges might manifest during experimental set up and analysis. Keywords: anoxic experiments, hydrothermal systems, iron sulfide, ocean worlds