Martian meteorites are the only direct samples from Mars, thus far. Currently, there are a total of 262 individual samples originating from at least 11 ejection events. Geochemical analyses, through techniques that are also used on terrestrial rocks, provide fundamental insights into the bulk composition, differentiation and evolution, mantle heterogeneity, and role of secondary processes, such as aqueous alteration and shock, on Mars. Martian meteorites display a wide range in mineralogy and chemistry, but are predominantly basaltic in composition. Over the past six years, the number of martian meteorites recovered has almost doubled allowing for studies that evaluate these meteorites as suites of igneous rocks. However, the martian meteorites represent a biased sampling of the surface of Mars with unknown ejection locations. The geology of Mars cannot be unraveled solely by analyzing these meteorites. Rocks analyzed by rovers on the surface of Mars are of distinct composition to the meteorites, highlighting the importance of Mars missions, especially sample return. The Mars 2020 Perseverance rover will collect and cache --- for eventual return to Earth --- over 30 diverse surface samples from Jezero crater. These returned samples will allow for Earth-based state-of-the-art analyses on diverse martian rocks with known field context. The complementary study of returned samples and meteorites will help constrain the evolution of the martian interior and surface. Here, we review recent findings and advances in the study of martian meteorites and examine how returned samples would complement and enhance our knowledge of Mars.

Combining geologic mapping and stratigraphic reconstruction of lava flows at Sapas, Maat and Ozza Montes, three potentially young volcanic structures of Atla Regio on Venus, with analysis of the spectral signature (radar emissivity anomalies) characterizing each mapped flow, Brossier et al. (2021) conclude that some of the lava flows at Maat Mons may be geologically recent (~25 Ma). The lava flows of Sapas and Ozza Montes are more consistent with weathered lava flows forming chlorapatite and some perovskite oxides. We discuss the reasons why, besides the importance of the results they obtained, the methodology they used can be very valuable for future investigations with higher resolution datasets. The importance of combining geologic interpretation with spectral analysis in the reconstruction of the volcanic history of Venus Considering its size, gravity and the presence of an atmosphere, Venus is typically considered as the twin sister of the Earth, but despite the apparent similarities with our planet, Venus is notably different because it is characterized by its extreme surface environment. With 90 bars and 475 °C, its surface is a very inhospitable place for life as we know it. Venus does not show evidence for a present plate tectonics-like activity, having a major part of its surface volcanic deposits younger than 300 Ma. It has been hypothesized that Venus underwent a catastrophic event of global resurfacing about 300 Ma ago, which may have almost entirely rejuvenated its surface (Schaber, 1992; Nimmo and McKenzie, 1998; Romeo and Turcotte, 2010; Strom et al., 1994; Turcotte et al., 1999). Some other studies instead favor a more equilibrium resurfacing model of the surface (Phillips et al, 1992; Phillips and Hansen, 1994; Bjonnes et al., 2012; O’Rourke and Korenaga, 2015). It is also possible that the past volcanic history of Venus somehow reflected an intermediate situation between these two end-member scenarios. Related to this topic, there has been a subject of debate whether or not the volcanism on Venus is currently evolving toward an equilibrium stage, with occurrences of smaller and more frequent localized eruptions. In this regard, it is vital to identify areas with current or recent volcanism, to measure the actual rate and volume of the most recent volcanic eruptions. The geologic interpretation and analysis of spectral signatures (both in radar and infrared wavelengths) can help us constraining the age of surface volcanic deposits on Venus. In geology, the so called “cross-cutting interrelationships” can constrain the relative age of two lava flows as it has been applied to young, possibly very recent lava flows and tectonic features on