Geology topics

B. Schmidt

Publications and source records attributed to B. Schmidt.

5 recordsLinked to original sources

USGS2024

Planned geological investigations of the Europa Clipper mission

Geological investigations planned for the Europa Clipper mission will examine the formation, evolution, and expression of geomorphic structures found on the surface. Understanding geologic features, their formation, and any recent activity are key inputs in constraining Europa’s potential for habitability. In addition to providing information about the moon’s habitability, the geologic study of Europa is compelling in and of itself. Here we provide a high-level, cross-instrument, and cross-discipline overview of the geologic investigations planned within the Europa Clipper mission. Europa’s fascinating collection of ice-focused geology provides an unparalleled opportunity to investigate the dynamics of icy shells, ice-ocean exchange processes, and global-scale tectonic and tidal stresses. We present an overview of what is currently known about the geology of Europa, from global to local scales, highlighting outstanding issues and open questions, and detailing how the Europa Clipper mission will address them. We describe the mission’s strategy for searching for and characterizing current activity in the form of possible active plumes, thermal anomalies, evidence for surface changes, and extremely fresh surface exposures. The complementary and synergistic nature of the data sets from the various instruments and their integration will be key to significantly advancing our understanding of Europa’s geology.

Space Science Reviews↗

USGS2020

Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians

Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations, by affecting population growth rate and local colonization-extinction processes. Dispersal can also influence evolutionary processes because it determines rates and patterns of gene flow in spatially structured populations and is closely linked to local adaptation. For these reasons, dispersal has received considerable attention from ecologists and evolutionary biologists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades, researchers have taken an interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography and genetics of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal. In particular, we emphasize the need to (1) quantify dispersal rate and distance rigorously using suitable model systems, (2) investigate the genetic basis and dispersal evolution patterns, and (3) examine dispersal-related eco-evolutionary dynamics. These proposed research avenues tap from the recent advances in quantitative and molecular methods and have the potential to improve our understanding of dispersal in organisms with complex life cycles.

The Quarterly Review of Biology↗

USGS2019

Conservation decisions under pressure: Lessons from an exercise in rapid response to wildlife disease

Novel outbreaks of emerging pathogens require rapid responses to enable successful mitigation. We simulated a 1‐day emergency meeting where experts were engaged to recommend mitigation strategies for a new outbreak of the amphibian fungal pathogen Batrachochytrium salamandrivorans . Despite the inevitable uncertainty, experts suggested and discussed several possible strategies. However, their recommendations were undermined by imperfect initial definitions of the objectives and scope of management. This problem is likely to arise in most real‐world emergency situations. The exercise thus highlighted the importance of clearly defining the context, objectives, and spatial–temporal scale of mitigation decisions. Managers are commonly under pressure to act immediately. However, an iterative process in which experts and managers cooperate to clarify objectives and uncertainties, while collecting more information and devising mitigation strategies, may be slightly more time consuming but ultimately lead to better outcomes.

Conservation Science and Practice↗

USGS2019

The NASA Roadmap to Ocean Worlds

In this article, we summarize the work of the NASA Outer Planets Assessment Group (OPAG) Roadmaps to Ocean Worlds (ROW) group. The aim of this group is to assemble the scientific framework that will guide the exploration of ocean worlds, and to identify and prioritize science objectives for ocean worlds over the next several decades. The overarching goal of an Ocean Worlds exploration program as defined by ROW is to “identify ocean worlds, characterize their oceans, evaluate their habitability, search for life, and ultimately understand any life we find.” The ROW team supports the creation of an exploration program that studies the full spectrum of ocean worlds, that is, not just the exploration of known ocean worlds such as Europa but candidate ocean worlds such as Triton as well. The ROW team finds that the confirmed ocean worlds Enceladus, Titan, and Europa are the highest priority bodies to target in the near term to address ROW goals. Triton is the highest priority candidate ocean world to target in the near term. A major finding of this study is that, to map out a coherent Ocean Worlds Program, significant input is required from studies here on Earth; rigorous Research and Analysis studies are called for to enable some future ocean worlds missions to be thoughtfully planned and undertaken. A second finding is that progress needs to be made in the area of collaborations between Earth ocean scientists and extraterrestrial ocean scientists.

Astrobiology↗

USGS2016

Cratering on Ceres: Implications for its crust and evolution

Thermochemical models have predicted that Ceres, is to some extent, differentiated and should have an icy crust with few or no impact craters. We present observations by the Dawn spacecraft that reveal a heavily cratered surface, a heterogeneous crater distribution, and an apparent absence of large craters. The morphology of some impact craters is consistent with ice in the subsurface, which might have favored relaxation, yet large unrelaxed craters are also present. Numerous craters exhibit polygonal shapes, terraces, flowlike features, slumping, smooth deposits, and bright spots. Crater morphology and simple-to-complex crater transition diameters indicate that the crust of Ceres is neither purely icy nor rocky. By dating a smooth region associated with the Kerwan crater, we determined absolute model ages (AMAs) of 550 million and 720 million years, depending on the applied chronology model.

Science↗