A latest Cretaceous to earliest Paleogene dinoflagellate cyst zonation of Antarctica, and implications for phytoprovincialism in the high southern latitudes

The thickest uppermost Cretaceous to lowermost Paleogene (Maastrichtian to Danian) sedimentary succession in the world is exposed on southern Seymour Island (65° South) in the James Ross Basin, Antarctic Peninsula. This fossiliferous shallow marine sequence, which spans the Cretaceous–Paleogene boundary, has allowed a high-resolution analysis of well-preserved marine palynomorphs. Previous correlation of Cretaceous–Paleogene marine palynomorph assemblages in the south polar region relied on dinoflagellate cyst biozonations from New Zealand and southern Australia. The age model of the southern Seymour Island succession is refined and placed within the stratigraphical context of the mid to high southern palaeolatitudes. Quantitative palynological analysis of a new 1102 m continuous stratigraphical section comprising the uppermost Snow Hill Island Formation and the López de Bertodano Formation (Marambio Group) across southern Seymour Island was undertaken. We propose the first formal late Maastrichtian to early Danian dinoflagellate cyst zonation scheme for the Antarctic based on this exceptional succession. Two new late Maastrichtian zones, including three subzones, and one new early Danian zone are defined. The oldest beds correlate well with the late Maastrichtian of New Zealand. In a wider context, a new South Polar Province based on Maastrichtian to Danian dinoflagellate cysts is proposed, which excludes most southern South American marine palynofloras. This interpretation is supported by models of ocean currents around Antarctica and implies an unrestricted oceanic connection across Antarctica between southern South America and the Tasman Sea

Resolving the Middle Jurassic dinoflagellate radiation: The palynology of the Bajocian of Swabia, southwest Germany

Dinoflagellates underwent a major radiation during the Bajocian (Middle Jurassic, ~ 170-168 Ma). The group originated in the Middle Triassic and dinoflagellate cysts were relatively low in diversity until the Bajocian, when over 100 species appeared. The Gonyaulacaceae expanded during this interval to become the dominant family of cyst-forming dinoflagellates, and has remained the principal dinoflagellate family throughout the Mesozoic and Cenozoic. However, Bajocian dinoflagellate cysts have received relatively little study. In order to unravel the pattern of the Bajocian dinoflagellate radiation, we have generated a high resolution, quantitative, palynological record through an expanded Middle Jurassic succession in Swabia, southwest Germany. Previous research has indicated a rapid, stepwise order of first appearances through the Bajocian. By contrast, we clearly demonstrate that there was a more gradual, continuous increase in diversity from the Late Aalenian to the Early Bathonian, although the number of first appearances was highest during the latest Early Bajocian to Late Bajocian. Major experimentation in excystment mode in the gonyaulacaceans occurred during the Late Aalenian and Early Bajocian, when multi-plate precingular, single-plate precingular and epicystal archaeopyle types first appeared. Through the integration of our data with published information from northwest Europe, we demonstrate that the appearance of dinoflagellate cyst taxa through the Late Aalenian�Early Bathonian appears to have been controlled by a major second-order transgression. Although the cause of this radiation is yet to be constrained, given the contemporaneous diversifications of other plankton groups, as well as ammonites, bivalves and fishes, it is likely that it formed part of the wider Mesozoic Marine Revolution. There is a prominent acme of Dissiliodinium giganteum in the Lower Bajocian which is a useful stratigraphical marker. Acanthaulax crispa is confirmed as a key index species for the Bajocian. One new species, Korystocysta aldridgeii sp. nov., is described

SurF: an innovative framework in biosecurity and animal health surveillance evaluation

Surveillance for biosecurity hazards is being conducted by the New Zealand Competent Authority, the Ministry for Primary Industries (MPI) to support New Zealand's biosecurity system. Surveillance evaluation should be an integral part of the surveillance life cycle, as it provides a means to identify and correct problems and to sustain and enhance the existing strengths of a surveillance system. The surveillance evaluation Framework (SurF) presented here was developed to provide a generic framework within which the MPI biosecurity surveillance portfolio, and all of its components, can be consistently assessed. SurF is an innovative, cross‐sectoral effort that aims to provide a common umbrella for surveillance evaluation in the animal, plant, environment and aquatic sectors. It supports the conduct of the following four distinct components of an evaluation project: (i) motivation for the evaluation, (ii) scope of the evaluation, (iii) evaluation design and implementation and (iv) reporting and communication of evaluation outputs. Case studies, prepared by MPI subject matter experts, are included in the framework to guide users in their assessment. Three case studies were used in the development of SurF in order to assure practical utility and to confirm usability of SurF across all included sectors. It is anticipated that the structured approach and information provided by SurF will not only be of benefit to MPI but also to other New Zealand stakeholders. Although SurF was developed for internal use by MPI, it could be applied to any surveillance system in New Zealand or elsewhere

Palaeoenvironment, palaeoclimate and age of the Brassington Formation (Miocene) of Derbyshire, UK

he Brassington Formation is the most extensive Miocene sedimentary succession onshore in the UK. Because of its unique position at the margin of NW Europe, the pollen from this lithostratigraphical unit provides evidence on the development of vegetation affected by North Atlantic currents and hypothesized atmospheric circulation changes during the Middle to Late Miocene climate cooling. Palynostratigraphy suggests that the uppermost Kenslow Member of the Brassington Formation is not coeval. Previously, all occurrences of the Kenslow Member were assumed to be contemporary. The oldest pollen assemblage is from the more southern Bees Nest Pit, which represents a subtropical conifer-dominated forest of late Serravallian age (c. 12 Ma). A younger assemblage was observed from the more northern Kenslow Top Pit; this indicates that a subtropical mixed forest was present during the early Tortonian (11.6–9 Ma). The shift from a conifer-dominated to a mixed forest was related to precipitation. Although the total precipitation did not change between the two assemblages, the younger assemblage had more uniform rainfall throughout the year. The diachronous nature of the Kenslow Member means that the depositional model of the Brassington Formation needs revising, and this will have implications for Neogene to recent uplift of the southern Pennines. Supplementary material: All valid formally defined palynomorph taxa below the generic level that are mentioned in this paper, with full author citations, are available at http://www.geolsoc.org.uk/SUP18889

Late Triassic dinoflagellate cysts from the Northern Carnarvon Basin, Western Australia

The Late Triassic radiation of cyst-forming dinoflagellates in the Southern Hemisphere is investigated in the Northern Carnarvon Basin, Western Australia. This major depocentre, situated on the southern margin of the Tethys Ocean, accumulated extensive deltaic and shallow marine successions at this time, that frequently host early dinoflagellate cyst assemblages. Numerous petroleum exploration wells in the basin have penetrated the fluvially dominated Mungaroo Formation and shallow marine Brigadier Formation, of Anisian–Norian and Rhaetian ages, respectively. Consequently, huge numbers of cuttings and sidewall core samples from these northwest prograding deltaic systems are available for study. Many of the dinoflagellate cysts from the Mungaroo and Brigadier formations have not been taxonomically formalised, including many forms that are used in open nomenclature within the oil and gas industry. This study formally documents these occasionally abundant and diverse dinoflagellate cyst assemblages with the aim of providing a consistent taxonomic framework for future work on the Upper Triassic successions of the Northern Carnarvon Basin. This will aid the recognition of individual flooding events via their characteristic palynomorph signatures and help to build on significant recent advances in regional sequence stratigraphy. One new genus, 14 new dinoflagellate cyst species and one new subspecies are described from the most diverse Late Triassic dinoflagellate assemblage yet published. A further nine genera and 15 dinoflagellate species are also recorded from the Carnian–Rhaetian R. wigginsii, W. listeri, H. balmei, R. rhaetica and D. priscum dinoflagellate zones. The documented assemblages are not only significant biostratigraphically, but it is also postulated that high diversity Triassic dinoflagellate cyst associations were paleoclimatically controlled, and were likely confined to the temperate and cool temperate paleolatitudes

Citing the taxonomic literature: what a difference a year makes

We all know that the world of scientific publishing has changed profoundly since the onset of the digital revolution. One relatively new development is the rapid publication of scientific papers online, frequently before they are copyedited and typeset, and sometimes even before being peer reviewed (Sheldon 2018). Climate of the Past is one such journal that posts manuscripts online before they have been refereed. The purpose of doing this is to allow online discussion of a manuscript while it is under review in the conventional sense. Manuscripts may thus benefit from any useful feedback from readers as well as from the formal reviews. The above developments mean that scientific articles may appear online long before being assigned to a particular volume/issue and with final page numbers. Such assignments commonly occur in the following year when the complete volumes or issues of a journal appear in print and/ or digitally. Before the digital revolution, authors had to wait perhaps 12 months or more between acceptance and final publication. Today, just a week or two may elapse before the typescript of an accepted manuscript is available online. In most respects this revolution is good, especially now that many authors aim for metricised output targets. However, such early publication of a paper may cause complications regarding its referencing, but in most cases this does not really matter so long as the reference in a bibliography leads to the retrieval of the correct publication. For example, the paper cited below as Pound and Riding (2015) was initially issued online in 2015, prior to assignment to a volume of the Journal of the Geological Society published in 2016. Before 2016 it would have also been cited as Pound and Riding (2015) but that situation would not have lasted for long and would have affected very few, if any, citations. Electronic publication of a paper prior to assignment of the volume number and final pagination can be confusing, but in most cases problems are limited to referencing. However, it has critical implications for papers with biological systematics, especially those with new nomenclatural proposals (new taxa, combinations, substitute names, etc. – so-called nomenclatural novelties). Until recently, codes of nomenclature in botany and zoology required nomenclatural novelties to be published in paper format in publicly distributed articles. However, the most recent codes permit the publication of nomenclatural novelties in a hybrid (online and paper) journal or even in a purely electronic periodical (but not in an online database or catalogue)

The role of the exit in the initial screening of investment opportunities: The case of business angel syndicate gatekeepers

The exit process has been largely ignored in business angel research.. The practitioner community identifies the difficulty in achieving exits as the most pressing problem for investors. This has been attributed to the failure of investors to adopt an exit-centric approach to investing. The validity of this claim is examined via a study of the investment approach of 21 ‘gatekeepers’ (managers) of angel groups in Scotland and Northern Ireland. Most gatekeepers say that they do consider the exit when they invest. However, this is contradicted by a verbal protocol analysis which indicates that the exit is not a significant consideration in their initial screening process. The small number of exits achieved by the groups is consistent with the general lack of an exit-centric approach to investing. Only three groups exhibit evidence of a strong exit-centric approach to investing. The lack of exits may have a negative impact on the level of future angel investment activity

Modelling and peeling extended sources with shapelets: a Fornax A case study

To make a power spectrum (PS) detection of the 21 cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to 'shapelets', an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular-resolution of the data is changed. We find that when increasing the angular-resolution of the data, the MS CLEAN model worsens at large angular-scales. When testing on real MWA data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed.Comment: 17 pages, 11 Figures, accepted for publication in Publications of the Astronomical Society of Australia (18/05/2020). "For the SHAMFI code, see: https://github.com/JLBLine/SHAMFI" . "For the SHAMFI documentation, see: https://shamfi.readthedocs.io/" . "For the WODEN code and documentation see: https://github.com/JLBLine/WODEN

Palynological, geochemical, and mineralogical characteristics of the Early Jurassic Liasidium Event in the Cleveland Basin, Yorkshire, UK

A previously proposed hyperthermal episode in the Early Jurassic (mid-Sinemurian) is investigated from the shallow marine succession at Robin Hood’s Bay, Cleveland Basin, Yorkshire, UK. Palynological study confirms that the stratigraphical extent of the distinctive dinoflagellate cyst Liasidium variabile corresponds very closely to the oxynotum Zone. The range of Liasidium variabile also corresponds to an overall negative excursion in carbon-isotopes measured in bulk organic matter, which here exhibits a double spike in the middle oxynotum Zone. Additionally, Liasidium variabile abundances track overall transgressive-regressive facies trends with peak abundance of dinoflagellate cysts corresponding to deepest water facies and maximum flooding. Lithological cycles (parasequences), defined by visual description and hand-held X-ray fluorescence analysis of powdered samples, match previously suggested short eccentricity cycles, and allow a total duration for the event of at least one million years to be suggested. Changes in clay mineralogy throughout the section determined by whole rock X-ray diffraction and scanning electron microscopy are shown to be largely related to authigenic processes, and neither support nor refute the proposition of coeval palaeoclimate changes. The combined characteristics of the Liasidium Event described from Robin Hood’s Bay are similar to, but much less extreme than, the Early Jurassic Toarcian Oceanic Anoxic Event albeit, at this locality, there is no evidence for the development of significant bottom water deoxygenation

Gridded and direct Epoch of Reionisation bispectrum estimates using the Murchison Widefield Array

We apply two methods to estimate the 21~cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly-spaced triangles of antenna tiles, as well as an estimate based on data gridded to the $uv$-plane. The direct and gridded bispectrum estimators are applied to 21 hours of high-band (167--197~MHz; $z$=6.2--7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 hours, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21~cm bispectrum may be accessible in less time than the 21~cm power spectrum for some wave modes, with detections in hundreds of hours.Comment: 19 pages, 10 figures, accepted for publication in PAS