Jorge Acosta, “Extended, High-Temperature Cooling of Lava Tube Interiors: Analog for Venus”
Mentor: Lindsay McHenry, Geosciences
Poster # 75

This project is analyzing lava samples from lava tubes at Craters of the Moon National Monument using X-ray diffraction (XRD) to determine their mineralogical composition. The analyzed material (sample) is finely ground and its bulk mineralogical composition is determined. The data collected will contrast the surface with the interior. When exposed to high temperatures in an oxidizing environment over periods of weeks to months in a laboratory experiment, the mineral olivine (common in basalt) develops a thin veneer of hematite, which can mask its spectral signature. Venus is difficult to study remotely (thick atmosphere) and the extreme temperatures at the surface (~475°C) and atmospheric pressures (~90 bars) makes the surface uninhabitable and difficult to study using landers or rovers (Fegley et al., 1995). However, olivine has been detected on Venus remotely, since it has absorptions in one of few spectral “windows” of Venus’ atmosphere that allow light to pass. Therefore, the objective is to determine if Lava tube interiors are an adequate analog for Venus. If there is a trend in specular hematite coating on interior surfaces of lava tubes, then it indicates that it is a good match for experimental results under Venus temperature conditions (Filiberto et al., 2020). If the surface layer is hematite-bearing and lacks olivine, but the interior contains olivine, then we might be able to study high-T weathering processes on Earth, in this environment. If it is more silicic (olivine free) the compositions of the surface could indicate that early Venus was cooler, wetter, and potentially more habitable (e.g. Basilevsky et al., 2012). Questions rise such as: could Venus have had a more hospitable environment early on? Perhaps could it have had liquid water, or even oceans (e.g. Driscoll and Bercovici, 2013), on its surface? If so, what went wrong?