ABSTRACT Formation of the Central European tektites, known as moldavites, has been associated with a large meteorite impact in southern Germany 14.8 m.y. ago. The geochemical link between moldavites and their source materials, and the processes of their possible chemical differentiation still remain uncertain. Some differences in chemical composition between moldavites and sediments of corresponding age from the surroundings of the Ries crater could be explained by a hypothesis according to which biomass covering the pre-impact area contributed to the source materials. In a comparison of the geochemical compositions of a large representative set of moldavites and suitable Ries sediments, enrichment in elements K, Ca, Mg, and Mn and depletion of Na in moldavites, similar to redistribution of these elements during their transfer from soil to plants, could indicate the unconventional biogenic component in moldavite source materials. Simple mixing calculations of the most suitable Ries sediments and a model biogenic component represented by burned biomass residue are presented. The plausibility of the estimated biomass contribution considering reconstructions of the middle Miocene paleoenvironment in the pre-impact Ries area is discussed. No significant vapor fractionation is required to explain the observed variability of moldavite chemical composition.

ABSTRACT Layered deposits on Mars imaged by the three rovers are generally inferred to have been deposited by liquid water (or wind or volcanism), consistent with interpretations based on orbital imaging. This interpretation implies early Mars was warm and wet, despite long-standing problems with modeling this case. As an alternative hypothesis, rapid sediment deposition during Late Noachian impact bombardment followed by local hydration and alteration of sediment by surficial acid condensates and (at least in Gale Crater) by chemically neutral groundwater can explain all the observed sediment features, such as ubiquitous low-angle cross-bedding, primitive basaltic compositions, persistent acidic salts, abundant amorphous materials, immature clays, high friability with low bulk densities, planar scoured unconformities, and rounded cobbles from rock tumbling. In other words, the ground-observed mineralogy, geochemistry, and sedimentology do not require and even are inconsistent with deposition from liquid water. Unlike the Moon, early Mars is believed to have had an atmosphere and water, perhaps mostly frozen. If so, impacts should have formed turbulent ground-hugging impactoclastic density currents capable of traveling hundreds of kilometers, and even globally. As terrestrial analogs, smaller-scale density currents are widespread around explosive volcanoes and nuclear test sites, whereas terrestrial impact analogs are lacking. Steam condensation on particles causes accretionary lapilli to form, grow to a maximum size, and fall out on layered deposits, and similar spherules have been observed by two of three rovers. Explaining these spherules as normal sedimentary concretions at Meridiani Planum required ignoring some of the observations. Ancient sediments on Mars that superficially resemble terrestrial aqueous deposits could therefore actually have resulted from impact cratering, the dominant geologic process in the early solar system.

ABSTRACT Suborbital analysis (SA) is presented here as the study of ballistics around a spherical planet. SA is the subset of orbital mechanics where the elliptic trajectory intersects Earth’s surface at launch point A and fall point B , known as the A -to- B suborbital problem, both launch and fall points being vector variables. Spreadsheet tools are offered for solution to this problem, based on the preferred simplified two-body model. Although simplistic in top-level description, this problem places essential reliance on reference frame transformations. Launch conditions in the local frame of point A and rotating with Earth require conversion to the nonrotating frame for correct trajectory definition, with the reverse process required for complete solution. This application of dynamics requires diligent accounting to avoid invalid results. Historic examples are provided that lack the requisite treatment, with the appropriate set of solution equations also included. Complementary spreadsheet tools SASolver and Helix solve the A -to- B problem for loft duration from minimum through 26 h. All provided spreadsheet workbook files contain the novel three-dimensional latitude and longitude plotter GlobePlot. A global ejecta pattern data set calculated using SASolver is presented. As visualized through GlobePlot, SASolver and Helix provide solutions to different forms of the A -to- B problem, in an effort to avoid errors similar to the historic misstep examples offered as a supplement. Operating guidelines and limitations of the tools are presented along with diagrams from each step. The goal is to enable mechanically valid interdisciplinary terrestrial ejecta research through novel perspective and quality graphical tools, so others may succeed where 1960s National Aeronautics and Space Administration researchers did not.

ABSTRACT Quantitative insights into the geochemistry and petrology of proximal impactites are fundamental to understand the complex processes that affected target lithologies during and after hypervelocity impact events. Traditional analytical techniques used to obtain major- and trace-element data sets focus predominantly on either destructive whole-rock analysis or laboratory-intensive phase-specific micro-analysis. Here, we present micro–X-ray fluorescence (µXRF) as a state-of-the-art, time-efficient, and nondestructive alternative for major- and trace-element analysis for both small and large samples (up to 20 cm wide) of proximal impactites. We applied µXRF element mapping on 44 samples from the Chicxulub, Popigai, and Ries impact structures, including impact breccias, impact melt rocks, and shocked target lithologies. The µXRF mapping required limited to no sample preparation and rapidly generated high-resolution major- and trace-element maps (~1 h for 8 cm 2 , with a spatial resolution of 25 µm). These chemical distribution maps can be used as qualitative multi-element maps, as semiquantitative single-element heat maps, and as a basis for a novel image analysis workflow quantifying the modal abundance, size, shape, and degree of sorting of segmented components. The standardless fundamental parameters method was used to quantify the µXRF maps, and the results were compared with bulk powder techniques. Concentrations of most major elements (Na 2 O–CaO) were found to be accurate within 10% for thick sections. Overall, we demonstrate that µXRF is more than only a screening tool for heterogeneous impactites, because it rapidly produces bulk and phase-specific geochemical data sets that are suitable for various applications within the earth sciences.