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The early Permian represents a crucial period of climate change in Gondwana. This climate signature is captured in the palynological record that represents the floral assemblage of the region. Palynofacies analysis of the No. 2 Coal Seam of the Highveld Coalfield provides a high-resolution picture of this climatic shift, as well as detailing the vegetation patterns and local environments. Core samples taken from two localities were studied with respect to the characteristics of the plant debris and the palynomorph assemblages to differentiate between regional and local signatures. At both of the sampling localities, the No. 2 Coal Seam is split into a Lower Coal Seam and an Upper Coal Seam by a siltstone and a sandstone intraseam parting, respectively. The uneven palaeotopography and distal depositional environment of the Highveld Coalfield distinguish it from the northern Witbank Coalfield as a river-dominated delta plain, with differences in the palaeoenvironment at each locality. Results from the Lower Coal Seam indicate a fern-dominated lowland and conifer-dominated upland. This gives way to a Glossopteris-dominated lowland and a diverse gymnospermous assemblage in the upland of the Upper Coal Seam. This change in floral composition is also observed in the adjacent Witbank Coalfield and is likely caused by climate amelioration related to the movement of Gondwana away from the South Pole.

This paper presents a new approach to the spent nuclear fuel (SNF) problem, which is uniquely enabled by a liquid fuel form, specifically as in the case of molten salt reactor (MSR) systems. Managing the SNF problem is critical for public acceptance of nuclear power as a climate change solution. An MSR can be refueled while operating by adding more fresh fuel salt, which grows the in-core fuel salt volume. This growth will eventually double the size of the original fuel salt, allowing to start another core with this excess fuel so long as the daughter reactor is of the same design and there is sufficient excess fuel. This study explores how such a "sourdough" strategy would work in MSRs and provides an initial calculation methodology to find the correct refueling rates to match the desired growth curve of power generation. Higher uranium enrichment levels of the refuel salt result in lower refueling rates and thus a longer doubling time. As a result, the refuel salt uranium enrichment can be tailored to match a postulated clean power generation capacity expansion. This approach allows postponing the spent nuclear fuel disposal issue using the sourdough method. Along with the MSR fuel's unique properties, it suggests a new path towards managing nuclear waste until long-term solutions become economically viable. [ABSTRACT FROM AUTHOR]

The Aramac Coal Measures in the Galilee Basin represent the early transition from a cold to a cool-temperate climate at the terminus of the Late Palaeozoic Ice Age (LPIA). The aim of this study is to examine the record of deglaciation and the establishment of the peat-forming Glossopteris-flora. Two boreholes, Longreach 1-1B and Muttaburra 1. were sampled to compare palynological and carbon isotope records alongside coal petrology. Palynological samples yield high abundances of striate bisaccate pollen derived from glossopterids, along with spores represent fem, horsetail and lycopsid undergrowth. Aquatic palynomorphs are rare but are indicative of freshwater conditions with no marine influence. These results reflect the quick establishment of Glossopteris-Qora following the glaciation. Coals from both sections show a degree of variability can be observed in the coals between each borehole. Coal seams in both holes show relatively low maturity for Australian Permian coals (vitrinite reflectance between 0.5% and 0.6%). Muttaburra 1 features fewer and thinner coal seams than Longreach 1 - IB. Coals from Longreach 1-1B tend to have a higher abundance of minerals and variable vitrinite/inertinite rations. Coals in Muttaburra 1 feature higher inertinite proportions. The liptinite component is made up mainly of sporinite and cutinite, but exsudatinite is also present filling pore space in the fusinites. The thin seams in the lower part of the Aramac Coal Measures feature higher proportions of liptinite, which tends to decrease upsection. With regards to intraseam variability, increases in inertinite can be observed in some seams in Longreach 1-1B, but not observed in Muttaburra 1. Organic carbon isotope values are within the expected range for C3 terrestrial plants. These values show an apparent cyclicity which may be related to climatic changes and humidity changes affected by the Pl and P2 glaciations. The timing of the deposition of the Aramac Coal Measures coincides with the P2 glaciation. Peat-formation either occurred distally from the position of the ice sheets or during brief interglacial phases. The high inertinite proportions indicate fire and/or fungal degradation of within the mire. Sedimentological evidence suggests permafrost was present during the formation of at least some proportion of the coal seams. [ABSTRACT FROM AUTHOR]