External controls on sedimentary sequences: a field and analogue modelling-based study

The Carboniferous Central Pennine Basin provides an ideal testing ground to examine the effects of tectonic activity, climate variation, sea-level changes and evolving bathymetric conditions upon continental to marine strata. During deposition of the glacio-eustatically controlled Millstone Grit Group the bathymetry of the area changed, tectonic activity has been invoked to explain basin-margin unconformities and high frequency climate variations have been interpreted as a driver of small-scale cyclicity. Tectonic activity does not appear to have affected the stratigraphic character of the Millstone Grit Group significantly. The inference of a major tectonic unconformity on the northern margin of the Central Pennine Basin is re-interpreted through recognition of an incised valley. The influence of active tectonics is minor but tectonic lineaments provide loci for syn-depositional structural activity. Facies analysis of Gilbert-type deltas within incised valley fills indicates a highly variable flow regime. Contrastingly, Gilbert-type deltas during sea-level fall are formed under constant, low flow conditions. This difference is tentatively linked to variable monsoonal discharge. Bathymetric differences combined with sea-level variations strongly influence stratigraphic development. Shelf height is inferred as a control on valley incision based on analogue modelling, detailed field investigation of the oldest part, and literature review of the entire Millstone Grit Group. The deepest incised valleys occur where fluvial systems incised into the highest shelf margins. Analogue modelling indicates that deep incised valleys are associated with increased sediment supply to the slope relative to incised valleys formed on lower shelf margins during the same magnitude sea-level falls (in agreement with field data). Additionally, lateral variations in shelf-margin height appear to have steered the positions of fluvial systems, increasing the likelihood of valley incision in specific locations. Integrating basin depth and basin-margin morphology in sequence stratigraphic models as a controlling factor on the behaviour and position of fluvial systems might thus improve insight into the position and size of incised valley systems and associated turbidite lowstand fans

Aromatic structure degradation of single layer graphene on an amorphous silicon substrate in the presence of water, hydrogen and Extreme Ultraviolet light

In this paper we study the reaction of water and graphene under Extreme Ultraviolet (EUV) irradiation and in the presence of hydrogen. In this work, single layer graphene (SLG) on amorphous Si as an underlying substrate was dosed with water (0.75 ML) and exposed to EUV (λ = 13.5 nm, 92 eV) with partial pressures of H2 in the background. The results show that the aromatic structure of graphene, when exposed to EUV and H2, breaks down into aryl ketones and enols of 1,3 di-ketone. Infrared (IR) spectroscopy shows that SLG oxidizes, with increasing H2 pressure leading to the grain boundary edges of graphene forming ketones and carboxylic acids. In situ and post exposure analyses also reveal that EUV exposure reduces the sp2 content of the graphene layer, with the sp3 content increasing, resulting in a more defective graphene layer

Wavelength separation from extreme ultraviolet mirrors using phaseshift reflection

A generic design and fabrication scheme of Mo/Si multilayer-grating phaseshift reflector systems is reported. Close to optimized extreme ultraviolet (EUV, λ=13.5  nm ) reflectance values up to 64% are demonstrated, while the diffractive properties can be exploited in spectral filtering applications. The results can contribute to a wavelength-unspecific solution for the suppression of λ>100  nm out-of-band radiation in EUV lithography