The heavily faulted Martian terrains of Ceraunius Fossae and Tractus Fossae, south of the Alba Mons volcano, have previously only been considered as parts of larger tectonic studies of Alba Mons, and the complexity of the faulting remains consequently unclear. As these terrains are in midst of the large Tharsis’ volcanoes, the study of their surface deformation has the potential to help unravel the volcano-tectonic deformation history associated with the growth of Tharsis, as well as decipher details of the responsible magma-tectonic processes. In this study, we distinguish between faults and collapse structures based on image and topographic evidence of pit-crater chains. We mapped ~12,000 faults, which we grouped into 3 distinct fault groups based on orientation, morphology, and relative ages. These show a temporal evolution in the mapped fault orientations from NE to NS to NW, with associated perpendicular stress orientations. Collapse features were also mapped and categorized into 4 different groups: pit-crater chains, catenae, u-shaped troughs and chasma. Examining the 4 collapse structures reveals that they are likely 4 different steps in the erosional evolution of pit-crater chains. Together this revealed a structural history heavily influenced by both local (radial to Alba Mons, Pavonis Mons and Ascraeus Mons) and regional (Tharsis radial) lateral diking, and vertical diking from a proposed Ceraunius Fossae centred magma source. This, along with an updated crater size-frequency distribution analysis of the unit ages, reveals a highly active tectonic and magmatic environment south of Alba Mons, in the Late Amazonian.

Numerous graben features transect the Tempe Terra plateau in the northeastern Tharsis Rise, making it one of the most heavily structured regions of Tharsis. The origin of the complex fault geometries, generated over three distinct stages of tectonic activity, is still poorly understood. This work distinguishes between locally-sourced and regionally-sourced structures within Tempe Terra, to isolate regional deformation patterns related to the general development of the Tharsis Rise from the effects of local mechanisms. Comparison of structural observations to predicted deformation patterns from different sources of graben formation in the Martian crust demonstrates the important role of magmatic activity at a variety of scales in driving tectonism in Tempe Terra. Noachian (Stage 1) faulting was the result of local magmatic underplating and associated heating and uplift, which formed part of an incipient stage of widespread Tharsis volcanism that predated development of the main Tharsis Rise. Early Hesperian (Stage 2) faults reflect the interaction of regional stresses from growth of the Tharsis Rise with magmatic activity highly localised along the Tharsis Montes Axial Trend – a linear volcanotectonic trendline including the alignment of the Tharsis Montes volcanoes. Early–Late Hesperian (Stage 3) faulting resulted from a series of dyke swarms from a Tharsis-centred plume, which propagated in a regional stress field generated by growth of the Tharsis Rise. As only Stage 2 NNE faults and Stage 3 ENE faults are linked to regional, Tharsis-related stresses, other observed Tempe Terra fault trends can be excluded when evaluating models of Tharsis’s tectonic evolution.

The Jovian moon Io features hundreds of paterae, broad depressions often filled with lava. The largest such example, Loki Patera, features a large, polygonal, and fractured island in its center. This island may reflect the fragmentation of the upper Ionian lithosphere by a shallow magma body, facilitated by a great number of shallow extensional structures. We propose a model for the Ionian lithosphere in which the upper portion is heavily deformed by joints, normal faults, and graben resulting from combined tidal, subsidence, and thermal stresses, and a lower portion rife with major thrust faults formed by horizontal compression of deeper crustal levels from the continued burial of surface units. Some of those thrusts may be reactivated normal faults. An extensionally fractured upper lithosphere accounts for the Loki Patera island, for observations of more than 175 paterae with straight edges, for the fact that almost 95% of Io’s surface is covered with volcanic flow and plains units, and for widespread instances of mass wasting within Io’s gigantic mountain blocks. Additional, high-resolution image and topographic data are required to test this hypothesized model for the moon’s lithosphere.

The structurally complex region of Tempe Terra, located in the northeast of the Tharsis Rise on Mars, preserves deformation related to the growth of Tharsis and lies along the trendline formed by the Tharsis Montes volcanoes. We characterise the spatiotemporal tectonic evolution of Tempe Terra based on comprehensive structural mapping. From this mapping, we identified 16 cross-cutting fault sets and placed these in relative time order, based on a hybrid approach using cross-cutting relationships and buffered crater counting. We are thus able to provide a broad framework for understanding the timing of development for the Tharsis Rise and Tharsis Montes axial trend. Our work shows that Tempe Terra has experienced three distinct stages of tectonic activity from the Middle Noachian to the Late Hesperian. Stage 1 involved E--W extension followed by localised NE--SW extension, which produced local zones of N and NW faulting through the centre and west of Tempe Terra in the Noachian. Stage 2 produced intense NE-oriented faulting concentrated along the Tharsis Montes axial trend in the Early Hesperian as a result of a discrete period of NW--SE extension and local volcanism. Stage 3 involved NW--SE extension coinciding with Tharsis volcanic activity, which generated a regional fabric of ENE-trending graben distributed across Tempe Terra from the Early to Late Hesperian. We observe an overall peak in tectonic activity in the Early Hesperian and find that Tharsis-related extensional deformation in the form of NE-oriented radial faulting did not start in Tempe Terra until this time.

Venus is the planet in the Solar System most similar to Earth in terms of size and (probably) bulk composition. Until the mid-20th century, scientists thought that Venus was a verdant world—inspiring science-fictional stories of heroes battling megafauna in sprawling jungles. At the start of the Space Age, people learned that Venus actually has a hellish surface, baked by the greenhouse effect under a thick, CO2-rich atmosphere. In popular culture, Venus was demoted from a jungly playground to (at best) a metaphor for the redemptive potential of extreme adversity. However, whether Venus was much different in the past than it is today remains unknown. In this review, we show how now-popular models for the evolution of Venus mirror how the scientific understanding of modern Venus has changed over time. Billions of years ago, Venus could have had a clement surface with water oceans. Venus perhaps then underwent at least one dramatic transition in atmospheric, surface, and interior conditions before present day. This review kicks off a topical collection about all aspects of Venus’s evolution and how understanding Venus can teach us about other planets, including exoplanets. Here we provide the general background and motivation required to delve into the other manuscripts in this collection. Finally, we discuss how our ignorance about the evolution of Venus motivated the prioritization of new spacecraft missions that will essentially rediscover Earth’s nearest planetary neighbor—beginning a new age of Venus exploration.

Pit craters are enigmatic, quasi-circular depressions observed on rocky (e.g., Earth and Mars) and icy (e.g., Enceladus) planetary bodies, and numerous asteroids. These depressions are not related to meteorite impacts. Instead pit craters are thought to be generated by overburden collapse into a subsurface cavity (e.g., created by dilatational faulting), or volumetrically depleted zone (e.g., an evacuated magma reservoir or conduit). The surface size and distribution of pit craters should thus provide an important record of otherwise inaccessible subsurface processes. Because we cannot access the subsurface structure of pit craters observed on planetary surfaces, we rely on physical and numerical models to infer the subsurface processes linked to their formation. Here, we use 3D seismic reflection data to quantify the palaeosurface and subsurface geometry of pit craters. These data enable us to identify whether pit craters connect to and their formation thus related to underlying structures. We map 59, Late Jurassic pit craters deeply buried within a sedimentary basin, offshore NW Australia. We demonstrate that some pit craters extend down and appear physically connected to igneous dykes, whereas others connect to dyke-induced and tectonic faults, seemingly where faults are steeply dipping and dilatational. There are no apparent relationships between pit crater geometries (e.g., palaeosurface expression or vertical extent) and the different magmatic and fault-related mechanisms we infer drove their formation. Reflection seismology is a powerful tool for understanding how pit craters form and whether their surface expression can be used to reconstruct subsurface structures and processes on other planetary bodies.