The Mars rover Opportunity has explored Victoria crater, an approximately 750-meter eroded impact crater formed in sulfate-rich sedimentary rocks. Impact-related stratigraphy is preserved in the crater walls, and meteoritic debris is present near the crater rim. The size of hematite-rich concretions decreases up-section, documenting variation in the intensity of groundwater processes. Layering in the crater walls preserves evidence of ancient wind-blown dunes. Compositional variations with depth mimic those approximately 6 kilometers to the north and demonstrate that water-induced alteration at Meridiani Planum was regional in scope.
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http://dx.doi.org/10.1126/science.1170355 | DOI Listing |
Syst Biol
September 2024
School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia.
Crater lake fishes are common evolutionary model systems, with recent studies suggesting a key role for gene flow in promoting rapid adaptation and speciation. However, the study of these young lakes can be complicated by human-mediated extinctions. Museum genomics approaches integrating genetic data from recently extinct species are, therefore, critical to understanding the complex evolutionary histories of these fragile systems.
View Article and Find Full Text PDFProc Math Phys Eng Sci
September 2021
School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand.
Surtseyan eruptions are an important class of mostly basaltic volcanic eruptions first identified in the 1960s, where erupting magma at an air-water interface interacts with large quantities of slurry, a mixture of previously ejected tephra that re-enters the crater together with water. During a Surtseyan eruption, hot magma bombs are ejected that initially contain pockets of slurry. Despite the formation of steam and anticipated subsequent high pressures inside these bombs, many survive to land without exploding.
View Article and Find Full Text PDFScience
February 2020
Lowell Observatory, Flagstaff, AZ 86001, USA.
The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers.
View Article and Find Full Text PDFSteroids
January 2019
School of Chemical & Physical Sciences, Victoria University of Wellington, Wellington, New Zealand; Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand. Electronic address:
NMR-directed investigation of the two sponge association between Stelletta crater and Desmacella dendyi has resulted in the isolation of two new members of the rare 4-methylidene class of sterols. Craterol A (1) and B (2) represent the first examples of natural products reported from the species S. crater.
View Article and Find Full Text PDFProc Biol Sci
August 2018
Department of Aquatic Ecology, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
Adaptive radiation research typically relies on the study of evolution in retrospective, leaving the predictive value of the concept hard to evaluate. Several radiations, including the cichlid fishes in the East African Great Lakes, have been studied extensively, yet no study has investigated the onset of the intraspecific processes of niche expansion and differentiation shortly after colonization of an adaptive zone by cichlids. Haplochromine cichlids of one of the two lineages that seeded the Lake Victoria radiation recently arrived in Lake Chala, a lake perfectly suited for within-lake cichlid speciation.
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