John Group Research Articles

U–Pb zircon–rutile dating of the Llangynog Inlier, Wales: constraints on an Ediacaran shallow-marine fossil assemblage from East Avalonia

The Llangynog Inlier of south Wales contains an assemblage of Ediacaran macrofossils from a shallow-marine environment, including discoidal morphs of Aspidella and rare examples of Hiemalora , Palaeopascichnus and Yelovichnus . These are taxa found at other sites in the Avalonian microcontinent (e.g. Charnwood Forest and eastern Newfoundland) and in the younger White Sea Ediacaran assemblages. As the Charnwood fossils reflect a deep-water environment, and no macrofossils have been found in the Ediacaran rocks of the Long Mynd, the fossils of the Llangynog Inlier represent a unique glimpse of shallow-marine life in southern Britain (East Avalonia). However, the lack of absolute age constraints has hampered direct comparison with other assemblages. Here, we report in situ zircon and rutile U–Pb dates from a rhyolitic ash-flow layer of the Coed Cochion Volcaniclastic Member, Llangynog Inlier, which constrains the age of the fossiliferous strata. A weighted mean single grain zircon isotope dilution thermal ionization mass spectrometry U–Pb age of 564.09 ± 0.70 Ma is interpreted as the rhyolite's crystallization age. This age is consistent with in situ laser ablation inductively coupled plasma mass spectrometry zircon and rutile U–Pb dating. The Llangynog age temporally correlates these fossils to dated horizons within East Avalonia at the Beacon Hill Formation, Charnwood (565.22 ± 0.89 Ma) and the Stretton Shale Formation, Long Mynd (566.6 ± 2.9 Ma). Correlations to West Avalonia include the time-equivalent Fermeuse Formation, St John's Group, eastern Newfoundland (564.13 ± 0.65 Ma). The data presented here establish the biota of the Llangynog Inlier as a lateral equivalent to the similarly shallow-marine, tidally influenced ecosystem of the upper Fermeuse Formation. Intra-terrane depositional environmental variability also affects what is preserved in Avalonian fossil sites. Further, time-constrained geochemical data reinforce the Llangynog Inlier's classification within the Wrekin Terrane. Supplementary material : U–Pb data, reference material and figures showing sedimentary structures are available at https://doi.org/10.6084/m9.figshare.c.6965642

FRAMBOIDAL PYRITE SHROUD CONFIRMS THE ‘DEATH MASK' MODEL FOR MOLDIC PRESERVATION OF EDIACARAN SOFT-BODIED ORGANISMS

The mechanisms by which soft-bodied organisms were preserved in late Ediacaran deep-marine environments are revealed by petrographic and geochemical investigation of fossil-bearing surfaces from the Conception and St. John's groups (Newfoundland, Canada). Framboidal pyrite veneers are documented on fossil-bearing horizons at multiple localities. The pyrite is interpreted to have formed via microbial processes in the hours to weeks following burial of benthic communities. This finding extends the ‘death mask' model for Ediacaran soft-tissue preservation to deep-marine settings. Remineralization of pyrite to iron oxides and oxyhydroxides is recognized to result from recent oxidation by meteoric fluids in the shallow subsurface. Consideration of other global Ediacaran macrofossil occurrences reveals that pyrite is observed in association with Ediacaran macrofossils preserved in all four previously described styles of moldic preservation (Flinders-, Conception-, Fermeuse- and Nama-type). This suggests that replication of external morphology by framboidal pyrite was a widespread mechanism by which soft-bodied organisms and associated organic surfaces were preserved, in multiple facies and depositional environments, 580–541 million years ago. The extensive global burial of pyrite in medium- to coarse-grained clastics and carbonates is a previously unrecognized yet potentially significant geological sink of iron and sulfur, and may have contributed to rising atmospheric and marine oxygen concentrations across the late Ediacaran interval.

Paleoenvironmental analysis of Ediacaran strata in the Catalina Dome, Bonavista Peninsula, Newfoundland

Ediacaran strata in the Conception and St. John's groups that are exposed in the Catalina Dome, eastern Newfoundland, comprise a succession that is thinner but otherwise broadly similar to that known from the well-studied outcrops near Mistaken Point in southern Avalon Peninsula and Spaniard's Bay in northern Avalon. In all of these areas, strata consist of turbidites deposited in deep-water basin-plain and slope environments, but important differences help to constrain interpretations of basin history and Ediacaran paleobiology of eastern Newfoundland. A turbidite paleocurrent shift from easterly to southerly is consistent with the existing two-phase tectonic model for basin evolution previously proposed for the Avalon Peninsula. In the Catalina Dome, however, this shift occurred stratigraphically higher than at Mistaken Point but lower than at Spaniards Bay in the Avalon Peninsula. Probable seismoturbidites are common in the lower part of the Catalina succession, suggesting particularly active tectonism. Except in the very lowest 20 m of the succession (Drook and lowermost Mistaken Point formations) in which ash is absent, volcanic ash beds are both more common and more volumetrically significant throughout the succession than farther to the south and east, which suggests that deposition occurred closer to the volcanic arc. Volcanic ash beds persist higher stratigraphically, occurring within the Fermeuse Formation, which here contains diverse rangeomorph fossils in contrast with the low-diversity assemblage of Ediacaran discs prevalent in the Fermeuse Formation of the Avalon Peninsula. This distribution strongly reaffirms the importance of taphonomy in controlling the composition of deep-water Ediacaran assemblages.

Obituary: Dr John MG Davis PhD, DSc, FRCPath

Obituary: Dr John MG Davis PhD, DSc, FRCPath

Chapter 42 The deep-marine glaciogenic Gaskiers Formation, Newfoundland, Canada

Abstract In eastern Canada, the Neoproterozoic Gaskiers Formation (Fm.) consists of a thick diamictite–turbidite succession (250–300 m thick) that occurs within the deep-marine predominantly volcaniclastic turbidite units of the Conception Group (4–5 km thick). These rocks are well exposed on the coast of the Avalon Peninsula in eastern Newfoundland. The thick succession is considered by some to represent the final Neoproterozoic glacial event, known as the Gaskiers Glaciation c. 582–585 Ma. The Gaskiers Fm. appears to have accumulated in a volcanically-influenced arc-related basin within the confines of the Proterozoic peri-Gondwanan Avalon terrane, before rifting away from the Gondwanan margin in the early Palaeozoic, but it is not clear whether it was adjacent to the West African Craton or the Amazon Craton. It has also been argued that Avalon had already rifted from Gondwana by the late Proterozoic. Glacially striated clasts, dropstones, and chatter-marked garnets identify a glaciated source area, and clasts and matrix are of volcanic origin; pyroclastic flows and volcanic bombs are also present. As a result, there is a growing consensus that the Gaskiers Fm. records local glaciation of a high relief volcanic topography, owing its origin to the episodic downslope reworking of volcanic and glacial debris into a deep, rapidly subsiding basin. The volcanic nature of these deposits implies that local volcanic activity was coeval with deposition. A minimum age of the Gaskiers Fm. is constrained by a diverse assemblage of Ediacaran-type fossils in the upper Conception Group dated at c. 565±3 Ma and in the lower St. John's Group, which overlies the Conception Group. A maximum age for the Gaskiers is provided by a U–Pb date of 606 +3.7/–2.9) Ma in the Harbour Main volcanic rocks underlying the Gaskiers Fm. A thin limestone bed has also been identified at two localities in Conception Bay directly overlying the diamictite yielding strongly negative δ 13 C values.

Ediacaran biota on Bonavista Peninsula, Newfoundland, Canada

Newly found fossils in the Conception and St. John's groups of the Bonavista Peninsula considerably extend the known geographic distribution of the Ediacaran fossils in Newfoundland. They occur in deepwater sediments and are preserved as epireliefs, forming census populations underneath volcanic ash layers throughout a more than 1 km thick turbiditic sequence. the exposed fossiliferous units comprise the Mistaken Point, Trepassey, Fermeuse, and Renews Head formations. the remains are tectonically deformed, with long axes of elliptical discs aligned parallel to cleavage strike; shortening of originally circular bedding surface features is on the order of 30-50% (averaging ~35%).The assemblage includesAspidella, Blackbrookia, Bradgatia, Charnia, Charniodiscus, Fractofusus, Hiemalora, andIvesheadia.These occur throughout the succession, withAspidellabeing the most common genus, followed byCharniaandCharniodiscus.Four new taxa are described, with candelabra-like fossils with aHiemalora-like base referred toPrimocandelabrum hiemaloranumn. gen. and sp., bush-like fossils toParviscopa bonavistensisn. gen. and sp., ladder-like fossils toHadryniscala avalonican. gen. and sp., and string-like fossils with basal disc toHadrynichorde catalinensisn. gen. and sp. the remains also include dubiofossils. The stratigraphic ranges of some taxa on the Bonavista Peninsula are longer than previously reported from the Avalon Peninsula, withFractofususspindles present in the Trepassey Formation,Bradgatia, Charnia, Charniodiscus, andIvesheadiareaching as high as the Fermeuse Formation, andAspidellaextending into the middle of the Renews Head Formation. the spindles in the Trepassey Formation are comparable to those found mainly in the stratigraphically older Briscal Formation on the Avalon Peninsula.

Paleoenvironmental and basin analysis of the late Neoproterozoic (Ediacaran) upper Conception and St. John's groups, west Conception Bay, Newfoundland

The Conception and St. John's groups consist of deep-marine, fine-grained siliciclastic–volcaniclastic rocks with abundant impressions of Ediacaran body fossils. Based on previous tectonic reconstructions, these strata are interpreted to have accumulated during the transition from a fore arc (phase 1, ca. 630–560 Ma) to a strike-slip pull-apart basin (phase 2, ca. 560–540 Ma). The Drook and Mistaken Point formations accumulated during phase 1 and are characterized by tabular, thick- to medium-bedded turbidites (east-southeast paleoflow directions), contourites (southwest paleoflow directions), and volcanic ash beds. The high proportion of each bed consisting of TE (Bouma turbidite division) mudstone, and the lack of correlation between bed thickness and basal grain size, suggest ponding of the turbidity currents. The differences in paleoflow directions and texture between Conception Bay and equivalent units at Mistaken Point imply that the two areas may have been geographically isolated from each other; phase 1 deposition in the study area is inferred to have taken place in the basin-plain portion of a transversely supplied, partially confined sub-basin. This "west Conception sub-basin" is bounded to the east by outcrops of the older Harbour Main Group that we speculate may have been a topographic high separating the sub-basin from the main fore-arc basin located to the present-day east. The Trepassey and Fermeuse formations represent phase 2 and are characterized by tabular thin-bedded turbidites, slump deposits, and volumetrically minor amounts of volcanic ash that accumulated on a southwesterly prograding slope. The regional consistency of lithologies and paleoflow directions throughout the Avalon Peninsula suggest that basin differentiation was minimal at this time.

State Sponsorship and Community Environmental Groups: The Atlantic Coastal Action Program in Newfoundland

Introduction When the Canadian federal government announced in November 2002 that it would assume part of the cost involved in building a primary sewage treatment plant in St. Johns, Newfoundland and Labrador, thereby halting the flow of untreated waste into that city's harbor, no one was happier than the members and supporters of the St. John's Harbour ACAP (SJH). ACAP is the acronym for Atlantic Coastal Action Program, an initiative of Environment Canada that provides project funding for community environmental organizations active in coastal ecosystem issues. Newfoundland (1) has two ACAPs. Besides the St. John's group, there is one in Corner Brook, the Humber Arm ACAP (HA). Although the Corner Brook organization also sought sewage treatment for its region, it has made very little headway on the issue. In this study, we examine the two local environmental groups, focussing on two distinct questions. The first asks why one group had greater success than the other. Answering this question necessarily requires looking at the structures of the two organizations, their specific objectives, and the political context in which they operated. Our second question is somewhat less obvious. Both ACAPs can be considered to be environmental groups, because both receive funding from the Canadian government. We want to know how having federal sponsorship affects their relationships with not just Ottawa but with the provincial and local authorities as well. In particular, we ask how having a link to the federal government influenced the capacity of the two to deal with wastewater issues, if it did at all. To answer these questions, the paper proceeds through a series of steps. First, it looks at the question of state sponsorship of interest groups. It then lays out the two cases that make up the study, searching for difference in structure, objectives, or relations with the governments involved that can explain why they achieved different results. The article's conclusion summarizes the findings, suggests an explanation for the results, and comments on the impact of governmental sponsorship on the two and their work. State-sponsored Groups The development of environmental in Canada is a relatively recent phenomenon. Unlike other Anglo-American countries, there were virtually no conservation or environmental prior to the 1960s. Nevertheless, in a short period of time, about two thousand environmental were established involving an estimated one to two million Canadians (Wilson, 2002; Doern and Conway, 1994). Pluralist theory views the flourishing of interest as a natural product of liberal democratic societies. Other theories focussing more on the development of new social movement have provided explanations in terms of the rise of a new middle class, the nature of late capitalism, and the development of post-materialist attitudes. Despite different theoretical perspectives, are generally seen as autonomous organizations originating in civil society. Although some researchers have noted the significance of state funding for many environmental groups, insufficient attention has been paid to the role of the state in encouraging and supporting environmental groups. In their classification of interest groups, Whittington and Van Loon (1996) make a useful distinction between groups that have been primarily responsible for their own creation and maintenance (autonomous groups) and groups that have been either created or encouraged by government itself (state-sponsored groups). As with all classification systems, there is a degree of arbitrariness in determining what is and is not a state-sponsored group; the degree of state-sponsorship may vary from those that are essentially agencies of the state to those that obtain some minimal level of support from the state. As well, the concept of state sponsorship may be considered multidimensional, including such aspects as whether government was responsible for founding or encouraging the founding of the group, the degree of financial dependence upon government, and the degree of autonomy of the group in terms of setting objectives, selecting strategies to achieve their objectives, and the choice of key personnel. …

Appreciation of John Beynon

Many, many years ago, when I started to work in the field of mass spectrometry in Milan Polytechnic, I met John Beynon, not personally but through his book “Mass Spectrometry and its Applications in Organic Chemistry” (Elsevier, 1960), which represented for me the Bible to solve all the problems I was faced with in the mass spectrometric field. The continued interaction with that book, and the study of the scientific research published by John's group, was highly stimulating for me, but also somehow depressing, giving me the idea that I could never reach the level of knowledge and complete scientific view on mass spectrometry as John and his group had. So you can imagine my consideration of John: I felt him at so high a level that any personal and ‘familiar’ rapport with him seemed to me impossible. I moved to Padova and, in the organization of a meeting in the snowy winter of 1981, I invited John to participate. He accepted. Of course, for the above reasons, I behaved very formally (not an easy job for my character!) and John did the same. It was then a nice surprise when, after leaving John at the front door of his hotel, a snow ball reached my head: I looked around, thinking that some boy had taken me as an (easy!) target, and only after a few seconds did I realise that John was the attacker! Well, this was the end of any formal behaviour and the beginning of a wonderful friendship. I cannot forget the pleasant hours spent with John in Italy, Wales, England and Hungary with a drink in our hands and relaxed discussions on rugby, art, music and (why not?) mass spectrometry. Even with the passing of the years, my consideration of John's work did not change; when he came to visit our group, my colleagues, co-workers and I felt like hobbits during a visit from Gandalf! I am not able to find (especially in my poor English) the right words to express my feelings, so let me cite a few sentences from “The Prophet” by G. K. Gibran. Your friend is your needs answered. He is your field which you sow with love and reap with thanksgiving And he is your board and your fireside. For you come to him with your hunger, and you seek him for peace. Seek him always with hours to live. For it is his to fill you need, but not your emptiness. And in the sweetness of the friendship let there be laughter, and sharing of pleasures. For in the dew of little things the heart finds its morning and is refreshed. My best personal greetings to John!

Paleoenvironmental analysis of the late Neoproterozoic Mistaken Point and Trepassey formations, southeastern Newfoundland

The Mistaken Point and Trepassey formations (Conception and St. John's groups, respectively) comprise a terminal Neoproterozoic, deep-marine succession of fine-grained turbidites and volcanogenic deposits that are part of the Avalonian Terrane. Debris-flow beds, slumped units, the low dispersion of turbidity-current paleoflow directions, and the absence of wave-generated structures together indicate that the sediment was deposited on a deep-water, southeast- facing slope. Channels were not present in the study area. The upward increase in the abundance of slump structures suggests that these units represent toe-of-slope and mid-slope environments, respectively. These units prograded over basin-floor deposits of the Drook and Briscal formations, which have (axial) paleocurrent directions that are orthogonal to the inferred downslope flow that characterized the overlying deposits. Within the Mistaken Point and Trepassey formations, a diverse assemblage of soft-bodied, non-phototrophic Ediacaran organisms is preserved beneath volcanic ash layers on more than one hundred surfaces. Individual fossiliferous surfaces can be correlated up to several kilometres. The felling orientations of frondose fossils indicate that contour currents, as well as up- and downslope currents of tidal and (or) wind-forced origin, influenced the sea floor in the intervals between event beds when the organisms lived. The contour currents may have been responsible for sustaining the organisms in this deep-water setting. The current-produced inclination of the frondose organisms at the time of ash deposition allowed their preservation by preventing the accumulation of ash beneath them.

A brief history of the origin of minimum alveolar concentration (MAC).

Minimum alveolar anesthetic concentration: A standard of anesthetic potency. By Eger EI II, Saidman LJ, Brandstater B. Anesthesiology 1965; 26:756–63.The minimum alveolar concentration of anesthetic (MAC) necessary to prevent movement in response to a painful stimulus was relatively constant in dogs

The first named Ediacaran body fossil, Aspidella Terranovica

Aspidella terranovica Billings, 1872 was first described from the late Neoproterozoic Fermeuse Formation (St. John's Group) on the Avalon Peninsula of eastern Newfoundland, approximately 1km stratigraphically above the famous Ediacaran biota at Mistaken Point, and several kilometres below the base of the Cambrian. Aspidella has been reinterpreted perhaps more than any other Precambrian taxon, and has variously been regarded as a fossil mollusc or ‘medusoid’, a gas escape structure, a concretion, or a mechanical suction mark. Our studies indicate that Aspidella includes a wide variety of preservational morphs varying from negative hyporeliefs with a raised rim and ridges radiating from a slit (Aspidella‐type preservation), to flat discs with a central boss and sharp outer ring (Spriggia preservation), to positive hyporeliefs with concentric ornamentation (Ediacaria preservation). Specimens occur in a continuum of sizes, with preservational styles dependent on the size of the specimen and the grain size of the host lithology; the elongation of specimens is tectonic. Aspidella is confirmed as a body fossil from observations of complex radial and concentric ornamentation, mutually deformed borders in clusters of specimens, and occurrence on the same bedding planes as certain distinctive Ediacaran taxa. Aspidella is indistinguishable from, and has priority over, several of the most common genera of late Neoproterozoic discoidal body fossils worldwide. Similar fossils from Australia are interpreted as holdfasts of frond‐like organisms. The density of specimens in the Aspidella beds suggests levels of benthic biomass in the Neoproterozoic that could rival those of modern marine communities. The serial growth forms, PalaeopascichnusIntrites, Neonereites renariusYelovichnus, associated with Aspidella, are interpreted as body fossils of unknown affinities rather than trace fossils. A new, trilobed, Ediacaran body fossil, Triforillonia costellae gen. et sp. nov., is described from the Aspidella beds of the Fermeuse Formation.