The JPL rover Perseverance's investigations of Jezero crater's floor reveal that the ultramafic S & eacute;& iacute;tah formation and the overlying mafic M & aacute;az formation are deformed into a broad, low-amplitude structural dome. Mastcam-Z stereo images processed into digital outcrop models, together with RIMFAX ground-penetrating radar profiles, were used to reconstruct the three-dimensional stratal geometry of both units along a SW-NE transect across a southern domain of the dome called south S & eacute;& iacute;tah. Measurements from 3-D reconstructions show a progression from sub-horizontal layers in the central parts of the dome to dips <20 degrees away from the dome on its flanks, with M & aacute;az and underlying S & eacute;& iacute;tah layers dipping concordantly. RIMFAX profiles and imaging around the dome confirm that limb dips are continuous into the subsurface and form a flat-crested composite quaquaversal fold structure. S & eacute;& iacute;tah rocks in the fold core are up to 17 m higher than adjacent M & aacute;az lava flows, despite stratigraphically underlying them, a relationship attributed to structural uplift. Fold geometry, wavelength (similar to 1 km), and amplitude (similar to 30-50 m), match models of forced folding produced by inflation of shallow igneous intrusions. The most likely cause is the emplacement of a sill or laccolith beneath the crater floor, generating elastic bending of the overlying layers. This intrusion-driven uplift explains S & eacute;& iacute;tah's elevated position, constrains the deformation history of Jezero's crater floor units post-emplacement of the S & eacute;& iacute;tah and M & aacute;az formations, and supports a significant role for shallow magmatic intrusion in shaping intracrustal structures on Mars.
This article presents Prithvi-EO-2.0, a new geospatial foundation model (GFM) that offers significant improvements over its predecessor, Prithvi-EO-1.0. Trained on 4.2 million global time-series samples from NASA's Harmonized Landsat and Sentinel-2 data archive at 30-m resolution, the new model incorporates temporal and location embeddings for enhanced performance across various geospatial tasks. Through extensive benchmarking with GEO-Bench, the model outperforms the previous Prithvi-EO model by 8% across a range of tasks. It also outperforms six other GFMs when benchmarked on remote sensing tasks from different domains and resolutions (i.e., from 0.1 to 15 m). The results demonstrate the versatility of the model in both classical Earth observation (EO) and high-resolution applications. Early involvement of end-users and subject matter experts (SMEs) allowed constant feedback on model and dataset design, enabling customization across diverse SME-led applications in disaster response, land cover and crop mapping, and ecosystem dynamics monitoring. Prithvi-EO-2.0 is available as an open-source model on Hugging Face and IBM TerraTorch, with additional resources on GitHub. The project exemplifies the Trusted Open Science approach embraced by all involved organizations.
The Perseverance rover landed in Jezero crater on Mars, which once contained a lake of liquid water. We report the rock properties encountered by Perseverance during a 10-kilometer traverse extending over 400 meters in elevation, from beneath Jezero's western sedimentary fan to the upper crater rim. These rocks consist of coarse-grained olivine, magnesium and iron carbonates, silica, and phyllosilicates, including some of the oldest materials exposed within Jezero. We infer that these rocks formed by olivine accumulation in an igneous system of layered intrusions, followed by exposure to water and carbon dioxide, which caused extensive carbonation of the silicate minerals. Aqueous alteration was more pronounced at lower elevations. Higher-elevation exposures on the crater rim appear similar to olivine-rich rocks distributed over the wider Nili Fossae region.
Gamma-ray bursts are the most luminous electromagnetic events in the Universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess of a thousand seconds, referred to as ultra-long gamma-ray bursts. Here, we report the discovery of the longest gamma-ray burst ever seen with a similar to 25 000 s gamma-ray duration, GRB 250702B, and characterize this event using data from four instruments in the InterPlanetary Network and the Monitor of All-sky X-ray Image. We find a hard spectrum, subsecond variability, and high total energy, which are only known to arise from ultrarelativistic jets powered by a rapidly spinning stellar-mass central engine. These properties and the extreme duration are together incompatible with all confirmed gamma-ray burst progenitors and nearly all models in the literature. This burst is naturally explained with the helium merger model, where a field binary ends when a black hole falls into a stripped star and proceeds to consume and explode it from within. Under this paradigm, GRB 250702B adds to the growing evidence that helium stars expand and that some ultra-long GRBs have similar evolutionary pathways as collapsars, stellar-mass gravitational wave sources, and potentially rare types of supernovae.
The impactor flux record to Earth has largely been erased by active tectonics, weathering, and continual reworking of the crust. Instead, a record of highly siderophile elements (HSE: Re, Os, Ir, Ru, Rh, Pt, Pd, and Au) in lunar impactites has been used as aproxy for the type of impactor material added to the Earth-Moon system. Quantifying impactor mass and flux with the HSE can potentially be complicated by numerous secondary processes, however, including silicate-metal segregation and multiple impact heritage. In contrast, because oxygen has an invariant geochemical affinity, triple oxygen isotope compositions have the potential to offer a robust long-term record of impactor fluxes in complex mixtures such as regolith. Here, we use high-precision triple oxygen isotopes to deconvolve the influences of meteorite addition and silicate vaporization and identify a ubiquitous impactor contaminant comprised of partially evaporated CM or ureilite-like material representing at least 1 wt% of the lunar regolith. Water delivered to Earth by meteorite material over 4 billion years therefore is only a fraction of an ocean's worth of water but is a significant contributor to the ice reservoir of the lunar cold traps.
