Ar-40 to Ar-39 dating of pseudotachylites from the Witwatersrand basin, South Africa, with implications for the formation of the Vredefort Dome

The formation of the Vredefort Dome, a structure in excess of 100 km in diameter and located in the approximate center of the Witwatersrand basin, is still the subject of lively geological controversy. It is widely accepted that its formation seems to have taken place in a single sudden event, herein referred to as the Vredefort event, accompanied by the release of gigantic amounts of energy. It is debated, however, whether this central event was an internal one, i.e., a cryptoexplosion triggered by volcanic or tectonic processes, or the impact of an extraterrestrial body. The results of this debate are presented

Preliminary site report for the 2005 ICDP-USGS deep corehole in the Chesapeake Bay impact crater

First report for the ICDP-USGS 1.7-km-deep corehole drilled into the central part of the Chesapeake Bay impact crater during 2005

Discerning primary versus diagenetic signals in carbonate carbon and oxygen isotope records: An example from the Permian-Triassic boundary of Iran

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordSedimentary successions across the Permian-Triassic boundary (PTB) are marked by a prominent negative carbon isotope excursion. This excursion, found in both fossil (e.g., brachiopod) and bulk carbonate at many sites around the world, is generally considered to be related to a global carbon cycle perturbation. Oxygen isotopes also show a negative excursion across the PTB, but because δ18O is more prone to diagenetic overprint (especially in bulk carbonate), these data are often not used in palaeoenvironmental analyses. In the present study, bulk-rock and brachiopod δ13C and δ18O, as well as conodont δ18O, were analyzed in PTB successions at Kuh-e-Ali Bashi and Zal (NW Iran) in order to evaluate diagenetic overprints on primary marine isotopic signals. The results show that the use of paired C-O isotopes and Mn-Sr concentrations is not sufficient to identify diagenetic alteration in bulk materials, because δ13C-δ18O covariation can be due to environmental factors rather than diagenesis, and Sr/Ca and Mn/Ca ratios can vary as a function of bulk-rock lithology. Comparison of δ13C profiles shows that all bulk carbonate is altered to some degree, although the general bulk-rock trend mimics that of the brachiopod data with a systematic offset of -1.2(±0.4)‰. This suggests that the first-order δ13C trend in bulk carbonate is generally robust but that the significance of small-scale carbon isotope fluctuations is uncertain, especially when such fluctuations are linked to lithologic variation. The PTB interval, which is marked by a low-carbonate 'Boundary Clay' in the study sections, may be especially prone to diagenetic alteration, e.g., via late-stage dolomitization. Comparison of oxygen-isotope profiles for bulk rock and well-preserved fossils (both brachiopods and conodonts) shows that the former are offset by -2.1(±0.4)‰. Diagenetic modeling suggests that these offsets were the product mainly of early diagenesis at burial temperatures of ~50-80°C and water/rock ratios of <10. Authigenic carbonates precipitated during early diagenesis represent a potentially major sink for isotopically light carbon at a global scale that has received relatively little attention to date.TJA thanks the Sedimentary Geology and Paleobiology program of the U.S. National Science Foundation (NSF EAR-1053449), the NASA Exobiology program (NNX13AJ1IG), and the China University of Geosciences—Wuhan (SKL-GPMR program GPMR201301, and SKL-BGEG programBGL21407) for their support. This study was funded by Deutsche Forschungsgemeinschaft (DFG; projects KO1829/12-1, KO1829/12-2 and KO2011/8-1)

Scanning electron microscopy, cathodoluminescence, and Raman spectroscopy of experimentally shock metamorphosed quartzite

We studied unshocked and experimentally (at 12, 25, and 28 GPa, with 25, 100, 450, and 750°C pre-shock temperatures) shock-metamorphosed Hospital Hill quartzite from South Africa using cathodoluminescence (CL) images and spectroscopy and Raman spectroscopy to document systematic pressure or temperature-related effects that could be used in shock barometry. In general, CL images of all samples show CL-bright luminescent patchy areas and bands in otherwise non-luminescent quartz, as well as CL-dark irregular fractures. Fluid inclusions appear dominant in CL images of the 25 GPa sample shocked at 750°C and of the 28 GPa sample shocked at 450°C. Only the optical image of our 28 GPa sample shocked at 25°C exhibits distinct planar deformation features (PDFs). Cathodoluminescence spectra of unshocked and experimentally shocked samples show broad bands in the near-ultraviolet range and the visible light range at all shock stages, indicating the presence of defect centers on, e.g., SiO4 groups. No systematic change in the appearance of the CL images was obvious, but the CL spectra do show changes between the shock stages. The Raman spectra are characteristic for quartz in the unshocked and 12 GPa samples. In the 25 and 28 GPa samples, broad bands indicate the presence of glassy SiO2, while high-pressure polymorphs are not detected. Apparently,some of the CL and Raman spectral properties can be used in shock barometry

Seaweed-based Packaging Solutions

Introduction The use of single-use packaging materials has increased dramatically in recent decades in parallel with increasing trends in convenience and fast-food. Most of these packaging materials are made of non-biodegradable, petroleum-based polymers that have degradative impacts on the environment and contribute to the global plastic pollution crisis. Finding alternative packaging materials is an important step towards building a bio-based circular economy. Sustainable land-based macroalgae cultivation can provide a solution, as it eliminates land-use pressure on coastal areas, doesn’t interfere with recreational activities or agriculture, reduces seasonal limitations, allows for complete control over product quality, and ensures consistent quality and traceability. Here, we present the success story of land-based macroalgae production for sustainable packaging solutions in the food industry via the Mak-Pak and Mak-Pak Scale-Up projects. Materials and Methods An initial screening of local macroalgae species was conducted based on detailed knowledge of growth rates, seasonality, geographic range, edibility, iodine content, biochemical properties, bioactivity, robustness and ease of cultivation. Different combinations of selected macroalgae were tested to develop a biodegradable, edible packaging prototype that was rated by consumer tests. In a follow-up project, we are focusing on eliminating the biggest bottleneck: scaling-up biomass production. We have partnered with a local, innovative farmer to sustainably scale-up and optimize biomass production for our sustainable, biodegradable macroalgae-based packaging material for the food industry. Results Several species of suitable macroalgae were selected based on the screening protocol and a method for using different combinations of selected species is described in a patent application for the packaging prototype. The packaging prototype was positively reviewed in consumer tests, where the consumers were pleasantly surprised by the neutral taste and smell. We could also show that certain components of the macroalgae that are important for packaging functionality (e.g. antioxidant activity) could be optimized during land-based production in artificial seawater. Currently we are in the early stages of scaling-up production and selecting strains to optimize growth rates and robustness, where we can complete the life cycle of one selected species from single cells to mature gametophytes within 6 weeks. With controlled induction of reproduction, we can continually provide material for transplantation to large-scale systems. Discussion The Mak-Pak and Mak-Pak Scale-Up projects have been featured in numerous news articles, exhibitions, and podcasts throughout Germany, Europe and even New Zealand. Our experience has shown that there is a lot of public interest in macroalgae-based packaging solutions. Consumers have become aware of the plastic pollution crisis and are open to alternatives to plastic packaging. Consequently, we have recently seen rapid changes in packaging trends in the cosmetic and food industries. Here we show that it is possible to produce a biodegradable, edible packaging from macroalgae biomass for the food-industry. Not only is this a success story for sustainable aquaculture, but also for macroalgae cultivation in general. This project has increased public awareness of macroalgae and contributed to a dialogue about the diversity of products and services that macroalgae can provide as we strive towards a sustainable, circular economy. However, optimization of the raw material production as well as the packaging itself is still underway. Furthermore, limitations in the food-industry require that our raw material meets high quality standards. In other industries where the quality of the raw material is not a limiting factor, there is enormous potential for macroalgae-based packaging solutions

Structural evolution of the 40 km wide Araguainha impact structure, central Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The 40 kill wide Araguainha structure in central Brazil is a shallowly eroded impact crater that presents unique insights into the final stages of complex crater formation. The dominant Structural features preserved at Araguainha relate directly to the centripetal movement of the target rocks during the collapse of the transient cavity. Slumping of the transient cavity walls resulted in inward-verging inclined folds and a km-scale anticline in the outer ring of the structure. The Folding stage was followed by radial and concentric faulting, With down-ward displacement of kilometer-scale blocks around the crater rim. The central uplift records evidence for kin-scale upward movement of crystalline basement rocks from the transient cavity floor, and lateral moment of sedimentary target rocks detached Front the cavity walls. Much of the structural grain in the central uplift relates to structural stacking of km-scale thrust sheets of sedimentary strata onto the core of crystalline basement rocks. Outward-plunging radial folds indicate tangential oblate shortening of the strata during the imbrication Of the thrust sheets. Each individual sheet records all early stage of folding and thickening due to non-coaxial strains, shortly before sheet imbrication. We attribute this folding and thickening phase to the kilometer-scale inward movement of the target strata from the transient cavity walls to the central uplift. The Outer parts of the central uplift record additional outward movement of the target rocks, possibly related to the collapse of the central uplift. An inner ring structure at 10-12 km from the crater center marks the extent of the deformation related to the outward movement of the target rocks.434701716Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Barringer Family FundClaude Leon Foundation of South AfricaFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [05/51530-3

Metastatic pleomorphic sarcoma to left atrium

Although several thousand patients are diagnosed with sarcoma annually in the United States, metastases to the heart are very uncommon. In this case report, an overall low frequency cancer presents masquerading with common cardiac symptomology. This case illustrates the importance for detailed diagnostic cardiac evaluations and heightened suspicion by physicians to consider metastatic disease to the heart in cancer patients with cardiovascular complications. Also discussed is a review of surgical and chemotherapeutic options for this problem