The Zoophycos group of trace fossils is common in Carboniferous to recent marine strata and sediments, and is a common component of ichnofaunas in the Visean and Namurian stages of England and Wales. A review of new and published records indicates that it is often present in limestones and sandstones of Chadian to Arnsbergian age. Thereafter it is less common, and restricted to clastic rocks. There are no known records within Carboniferous strata above the lowest Westphalian. The form is most common and often abundant in limestones of the Yoredale facies in the upper Visean and lower Namurian stages of northern England, particularly so in northern Northumberland. Where detailed sedimentological data exist, they indicate that the organisms responsible for the Zoophycos group burrowed into unconsolidated carbonate substrate that was deposited under low accumulation rates, often affected by storm wave action and where seawater flow provided a nutrient supply. However, in mixed carbonate–clastic settings, the deep-tier nature of Zoophycos may indicate that the organism lived in overlying shallow-marine, clastic-dominated depositional environments and burrowed down into the carbonate substrate. The same may be true of siliciclastic depositional settings where the presence of Zoophycos in some sandstones may reflect the palaeoenvironment of the overlying, finer-grained transgressive marine (prodelta and distal mouth bar) deposits.Supplementary material: A spreadsheet with details of Carboniferous records of Zoophycos group fossils from England, Wales, the Isle of Man and the North Sea is available at https://doi.org/10.6084/m9.figshare.c.4994636
A critique of palynostratigraphic zonation schemes associated with the Langsettian-Duckmantian Stage boundary shows that, at high levels of stratigraphic resolution, most criteria used as palynological proxies for the position of the boundary are unsuitable. Most importantly, in the Duckmantian stratotype section the highest stratigraphic occurrence of the index species Schulzospora rara is above (rather than below or within) the Vanderbeckei Marine Band, the base of which defines the Duckmantian Stage. A cored section through the boundary in southern North Sea well 44/22-1 displays comparable microfloral distributions. While data are as yet too sparse to provide detailed answers, the findings have implications for understanding how marine flooding events affected Carboniferous microfloral evolution and extinction. Ultimately this influences how microfloral biozone boundaries relate to the regional European Upper Carboniferous stage boundaries, which are largely defined in relation to strata deposited during marine flooding events similar to that associated with the Langsettian-Duckmantian boundary. The miospore genus Sinuspores Artüz is emended, and two new taxa are described: Gondisporites bulboides sp. nov. and Hymenospora murdochensis sp. nov.
Evaporites characterize the Lopingian of Europe but present obstacles for biostratigraphic analysis. Here we present a case study for processing the Lopingian Zechstein Group evaporites of central-western Europe for the recovery of palynomorph assemblages. We demonstrate that full recovery is easily achieved with two main modes of palynomorph preservation observed; palynomorphs are either exceptionally well-preserved and orange-brown in colour, or poorly-preserved, brown-black, opaque and fragmented. The latter are reminiscent of palynomorphs of high thermal maturity. However, we propose that the intact nature of preservation is a result of the rapid growth of near-surface halite crystals, with their darkening a consequence of locally-enhanced heat flux due to the relatively high thermal conductivity of salt. This case study has enabled novel insight into an otherwise undescribed environment, and demonstrates the utility and possibility of extracting palynomorphs from a variety of rock salt types. This method should be applicable to a wide range of ancient evaporite and could also be applied to other Permian evaporite systems, which are used as analogues for extra-terrestrial environments.
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