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Facies variability of mudstones is likely greater than generally perceived, with important implications for their behaviour in major civil engineering, energy and waste disposal applications. Here, we explore this variability for the UK Oxford Clay, a widely studied Middle/Upper Jurassic mudstone. Evidence from wire-line logs, geochemistry, sequence stratigraphy and biofacies analyses are combined to reveal heterogeneity within the Peterborough Member (Lower Oxford Clay) and to explore the extent to which it blanketed basin features or responded dynamically to them. Thickness modelling suggests that the Mid North Sea High, formed by Mid Jurassic thermal doming, likely influenced sediment pathways, favouring thick sediment accumulation in the Wessex Basin, thinner successions across the East Midlands Shelf, and sediment starvation in the Weald Basin. Biofacies patterns, determined using a novel combination of detrended correspondence and cluster analysis, vary significantly and suggest a complex patchwork of environments related to local basin setting. The Type Section of the Peterborough Member seems to represent only a narrow range of conditions that influenced its deposition, and cautions against developing basin-scale models based on a few well exposed and heavily researched outcrop successions.

Correct interpretation of soft-bodied fossils relies on a thorough understanding of their taphonomy. While the focus has often been on the primary roles of decay and early diagenesis, the impacts of deeper burial and metamorphism on fossil preservation are less well understood. We document a sequence of late-stage mineral replacements in panarthropod fossils from the Sirius Passet Lagerstätte (North Greenland), an important early Cambrian Burgess Shale–type (BST) biota. Muscle and gut diverticula were initially stabilized by early diagenetic apatite, prior to being pervasively replaced by quartz and then subordinate chlorite, muscovite, and chloritoid during very low- to low-grade metamorphism. Each new mineral replicates the soft tissues with different precision and occurs in particular anatomical regions, imposing strong biases on the biological information retained. Muscovite and chloritoid largely obliterate the tissues’ original detail, suggesting that aluminum-rich protoliths may have least potential for conserving mineralized soft tissues in metamorphism. Overall, the fossils exhibit a marked shift toward mineralogical equilibration with the matrix, obscuring primary taphonomic modes. Sequential replacement of the phosphatized soft tissues released phosphorus to form new accessory monazite (and apatite and xenotime), whose presence in other BST biotas might signal the prior, more widespread, occurrence of this primary mode of preservation. Our results provide critical context for interpreting the Sirius Passet biota and for identifying late-stage overprints in other biotas.

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Farrell, U. C., Samawi, R., Anjanappa, S., Klykov, R., Adeboye, O. O., Agic, H., Ahm, A.-S. C., Boag, T. H., Bowyer, F., Brocks, J. J., Brunoir, T. N., Canfield, D. E., Chen, X., Cheng, M., Clarkson, M. O., Cole, D. B., Cordie, D. R., Crockford, P. W., Cui, H., Dahl, T. W., Mouro, L. D., Dewing, K., Dornbos, S. Q., Drabon, N., Dumoulin, J. A., Emmings, J. F., Endriga, C. R., Fraser, T. A., Gaines, R. R., Gaschnig, R. M., Gibson, T. M., Gilleaudeau, G. J., Gill, B. C., Goldberg, K., Guilbaud, R., Halverson, G. P., Hammarlund, E. U., Hantsoo, K. G., Henderson, M. A., Hodgskiss, M. S. W., Horner, Tristan J., Husson, J. M., Johnson, B., Kabanov, P., Brenhin K. C., Kimmig, J., Kipp, M. A., Knoll, A. H., Kreitsmann, T., Kunzmann, M., Kurzweil, F., LeRoy, M. A., Li, C., Lipp, A. G., Loydell, D. K., Lu, X., Macdonald, F. A., Magnall, J. M., Mänd, K., Mehra, A., Melchin, M. J., Miller, A. J., Mills, N. T., Mwinde, C. N., O'Connell, B., Och, L. M., Ossa Ossa, F., Pagès, A., Paiste, K., Partin, C. A., Peters, S. E., Petrov, P., Playter, T. L., Plaza-Torres, S., Porter, Susannah M., Poulton, S. W., Pruss, S. B., Richoz, S., Ritzer, S. R., Rooney, A. D., Sahoo, S. K., Schoepfer, S. D., Sclafani, J. A., Shen, Y., Shorttle, O., Slotznick, S. P., Smith, E. F., Spinks, S., Stockey, R. G., Strauss, J. V., Stüeken, E. E., Tecklenburg, S., Thomson, D., Tosca, N. J., Uhlein, G. J., Vizcaíno, M. N., Wang, H., White, T., Wilby, P. R., Woltz, C. R., Wood, R. A., Xiang, L., Yurchenko, I. A., Zhang, T., Planavsky, N. J., Lau, K. V., Johnston, D. T., Sperling, E. A., The Sedimentary Geochemistry and Paleoenvironments Project. Geobiology. 00, (2021): 1– 12,https://doi.org/10.1111/gbi.12462., Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable for several thousand samples, but not practical or scalable for larger, more complex datasets. As results have accumulated, researchers have increasingly gravitated toward larger compilations and statistical tools. New data frameworks have become necessary to handle larger sample sets and encourage more sophisticated or even standardized statistical analyses. In this paper, we describe the Sedimentary Geochemistry and Paleoenvironments Project (SGP; Figure 1), which is an open, community-oriented, database-driven research consortium. The goals of SGP are to (1) create a relational database tailored to the needs of the deep-time (millions to billions of years) sedimentary geochemical research community, including assembling and curating published and associated unpublished data; (2) create a website where data can be retrieved in a flexible way; and (3) build a collaborative consortium where researchers are incentivized to contribute data by giving them priority access and the opportunity to work on exciting questions in group papers. Finally, and more idealistically, the goal was to establish a culture of modern data management and data analysis in sedimentary geochemistry. Relative to many other fields, the main emphasis in our field has been on instrument measurement of sedimentary geochemical data rather than data analysis (compared with fields like ecology, for instance, where the post-experiment ANOVA (analysis of variance) is customary). Thus, the longer-term goal was to build a collaborative environment where geobiologists and geologists can work and learn together to, We thank the donors of The American Chemical Society Petroleum Research Fund for partial support of SGP website development (61017-ND2). EAS is funded by National Science Foundation grant (NSF) EAR-1922966. BGS authors (JE, PW) publish with permission of the Executive Director of the British Geological Survey, UKRI.

Molecular timescales estimate that early animal lineages diverged tens of millions of years before their earliest unequivocal fossil evidence. The Ediacaran macrobiota (~574 to 538 million years ago) are largely eschewed from this debate, primarily due to their extreme phylogenetic uncertainty, but remain germane. We characterize the development of Charnia masoni and establish the affinity of rangeomorphs, among the oldest and most enigmatic components of the Ediacaran macrobiota. We provide the first direct evidence for the internal interconnected nature of rangeomorphs and show that Charnia was constructed of repeated branches that derived successively from pre-existing branches. We find homology and rationalize morphogenesis between disparate rangeomorph taxa, before producing a phylogenetic analysis, resolving Charnia as a stem-eumetazoan and expanding the anatomical disparity of that group to include a long-extinct bodyplan. These data bring competing records of early animal evolution into closer agreement, reformulating our understanding of the evolutionary emergence of animal bodyplans.

The relative influence of niche vs. neutral processes in ecosystem dynamics is an on‐going debate, but the extent to which they structured the earliest animal communities is unknown. Some of the oldest known metazoan‐dominated paleocommunities occur in Ediacaran age (~ 565 million years old) strata in Newfoundland, Canada and Charnwood Forest, UK. These comprise large and diverse populations of sessile organisms that are amenable to spatial point process analyses, enabling inference of the most likely underlying niche or neutral processes governing community structure. We mapped seven Ediacaran paleocommunities using LiDAR, photogrammetry and a laser line probe. We found that neutral processes dominate these paleocommunities, with niche processes exerting limited influence, in contrast with the niche‐dominated dynamics of modern marine ecosystems. The dominance of neutral processes suggests that early metazoan diversification may not have been driven by systematic adaptations to the local environment, but instead may have resulted from stochastic demographic differences.

The Ediacaran macrofossil Charnia masoni Ford is perhaps the most iconic member of the Rangeomorpha: a group of seemingly sessile, frondose organisms that dominates late Ediacaran benthic, deep‐marine fossil assemblages. Despite C. masoni exhibiting broad palaeogeographical and stratigraphical ranges, there have been few morphological studies that consider the variation observed among populations of specimens derived from multiple global localities. We present an analysis of C. masoni that evaluates specimens from the UK, Canada and Russia, representing the largest morphological study of this taxon to date. We describe substantial morphological variation within C. masoni and present a new morphological model for this species that has significant implications both for interpretation of rangeomorph architecture, and potentially for existing taxonomic schemes. Previous reconstructions of Charnia include assumptions regarding the presence of structures seen in other rangeomorphs (e.g. an internal stalk) and of homogeneity in higher order branch morphology; observations that are not borne out by our investigations. We describe variation in the morphology of third and fourth order branches, as well as variation in gross structure near the base of the frond. The diagnosis of Charnia masoni is emended to take account of these new features. These findings highlight the need for large‐scale analyses of rangeomorph morphology in order to better understand the biology of this long‐enigmatic group.

Rangeomorphs dominate the Ediacaran Avalonian macrofossil assemblages of Charnwood Forest, UK (�562 Ma). However, their unfamiliar fractal architecture makes distinguishing phylogenetically reliable characters from intraspecific features difficult. Fortunately, spatial analysis of large in-situ populations offers an independent means of assessing their taxonomy. Populations of a single biological species are likely to exhibit similar spatial distributions due to their shared responses to the biological and ecological processes acting upon them. As such, spatial analyses can be used to interrogate which are the most taxonomically deductive characters in similar species. We used random labelling analyses to investigate the presence or absence of characters of Primocandelabrum boyntoni, P. aethelfalaedia, and P. aelfwynnia on the Bed ‘B’. The resultant spatial distributions were compared to observed characters using goodness-of-fit tests to determine which characters were associated with unique populations, and which were found across multiple populations. We found that P. boyntoni and P. aelfwynnia had statistically indistinguishable character distributions, suggesting that they represent a single biological species, and that they exhibited significantly different distributions to P. aethelfalaedia, suggesting that there are two (rather than three) species of Primocandelabrum present on the B surface. Furthermore, we found that the distribution of concealed versus unconcealed 1st order branches across all specimens exhibited significantly different density-dependant behaviour, with unconcealed branching occurring in areas of higher density populations and concealed branching occurring in the lower density areas of Primocandelabrum.We speculate that unconcealed branches may have been a response to the reduced availability of resources in higher density areas, implying rangeomorphs were capable of ecophenotypic responses.

The oceans of the early Cambrian (~541 to 509 million years ago) were the setting for a marked diversification of animal life. However, sea temperatures — a key component of the early Cambrian marine environment — remain unconstrained, in part because of a substantial time gap in the stable oxygen isotope ( d 18 O) record before the evolution of euconodonts. We show that previously overlooked sources of fossil biogenic phosphate have the potential to fill this gap. Pristine phosphatic microfossils from the Comley Limestones, UK, yield a robust d 18 O signature, suggesting sea surface temperatures of 20° to 25°C at high southern paleolatitudes (~65°S to 70°S) between ~514 and 509 million years ago. These sea temperatures are consistent with the distribution of coeval evaporite and calcrete deposits, peak continental weathering rates, and also our climate model simulations for this interval. Our results support an early Cambrian greenhouse climate comparable to those of the late Meso- zoic and early Cenozoic, offering a framework for exploring the interplay between biotic and environmental controls on Cambrian animal diversification.

Rangeomorphs from the Ediacaran of Avalonia are among the oldest known complex macrofossils and our understanding of their ecology, ontogeny and phylogenetic relationships relies on accurate and consistent classification. There are a number of disparate classification schemes for this group, which dominantly rely on a combination of their branching characters and shape metrics. Using multivariate statistical analyses and the diverse stemmed, multifoliate rangeomorphs in Charnwood Forest (UK), we assess the taxonomic usefulness of the suite of characters currently in use. These techniques allow us to successfully discriminate taxonomic groupings without a priori assumptions or weighting of characters and to document a hitherto unrecognized level of variation within single taxonomic groups. Variation within the currently defined genus Primocandelabrum is too great to be realistically assigned to different species and may instead reflect primary character diversity, ontogenetic changes in character state or ecophenotypic variability. Its recognition cautions against generic-level diagnoses based on single differences in character state and will be crucial in understanding the mode of growth of these enigmatic organisms. Supplementary material: Data tables, definition of the characters used in the analyses, and detailed descriptions and breakdowns of methods and results are available at https://doi.org/10.6084/m9.figshare.c.3726937

Although they are rare, fossilized gills are well known in Mesozoic coleoid cephalopods. In the Late Jurassic Solnhofen (South Germany) and Late Cretaceous Hâkel and Hâdjoula (Lebanon) plattenkalks, the feather-like gill remains are usually preserved as a yellowish staining. Small coleoids from Hâkel—tentatively determined as octopods—attracted our attention because these stains occur throughout the entire mantle sac in an unusual symmetrical pattern. Actualistic comparisons point to a compound of diverse vascular structures that most likely reflect central parts of the venous blood system (afferent branchial vessels, branchial hearts, vena pallialis, blood sinus) as well as the nephridial sacs. The nephridial sacs are clearly separated, which confirms the octopod nature of the fossils. A reticulated staining pattern in the rear of the mantle, which may reflect the gonad capillary system, suggests the presence of mature small-sized octopods. Based on its colour, its amorphous habit, and energy-dispersive X-ray spectroscopy (EDX) elemental analyses, the major components of the coelomic cavities have been replicated by an iron-rich phase (presumably goethite; copper was not detected). The goethite does not replace the tissues; rather, it traces their gross form as a well-defined “stain”. It is assumed the goethite is secondary after pyrite, which precipitated as a consequence of the oxygen-binding capacity of the copper-bearing haemocyanin and its ability to locally regulate redox potentials immediately postmortem.

U-Pb (zircon) ages for key stratigraphic volcanic horizons within the ∼3200-m-thick Ediacaran-age Charnian Supergroup provide an improved age model for the included Avalonian assemblage macrofossils and, hence, temporal constraints essential for intercomparisons of the Charnian fossils with other Ediacaran fossil assemblages globally. The Ives Head Formation (Blackbrook Group), the oldest exposed part of the volcaniclastic Charnian Supergroup of the late Neoproterozoic Avalonian volcanic arc system of southern Britain, contains a bedding plane with an impoverished assemblage of ivesheadiomorphs that is constrained to between ca. 611 Ma and 569.1 ± 0.9 Ma (total uncertainty). Higher-diversity biotas, including the holotypes of Charnia, Charniodiscus, and Bradgatia, occupy the upper part of the volcaniclastic succession (Maplewell Group) and are dated at 561.9 ± 0.9 Ma (total uncertainty) and younger by zircons interpreted as coeval with eruption and deposition of the Park Breccia, Bradgate Formation. An ashy volcanic-pebble conglomerate in the Hanging Rocks Formation at the very top of the supergroup yielded two U-Pb zircon populations: an older detrital one at ca. 604 Ma, and a younger population at ca. 557 Ma, which is interpreted as the approximate depositional age. The temporal association of the fossiliferous Charnian Supergroup with comparable fossiliferous deep-water successions in Newfoundland, and the probable temporal overlap of the youngest Charnwood macrofossils with those from different paleoenvironmental settings, such as the Ediacaran White Sea macrofossils, indicate a primary role for ecological sensitivity in determining the composition of these late Neoproterozoic communities.

Melanins are biological pigments found throughout the animal kingdom that have many diverse functions. Pump–probe imaging can differentiate the two kinds of melanins found in human skin, eumelanin and pheomelanin, the distributions of which are relevant to the diagnosis of melanoma. The long-term stability of the melanin pump–probe signal is central to using this technology to analyze melanin distributions in archived tissue samples to improve diagnostic procedures. This report shows that most of the pump–probe signal from eumelanin derived from a Jurassic cephalopod is essentially identical to that of eumelanin extracted from its modern counterpart, Sepia officinalis. However, additional classes of eumelanin signals found in the fossil reveal that the pump–probe signature is sensitive to iron content, which could be a valuable tool for pathologists who cannot otherwise know the microscopic distributions of iron in melanins.

Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions, including display, evasion, photoprotection, detoxification, and metal scavenging. To date, evidence of melanin in fossil organisms has relied entirely on indirect morphological and chemical analyses. Here, we apply direct chemical techniques to categorically demonstrate the preservation of eumelanin in two > 160 Ma Jurassic cephalopod ink sacs and to confirm its chemical similarity to the ink of the modern cephalopod, Sepia officinalis. Identification and characterization of degradation-resistant melanin may provide insights into its diverse roles in ancient organisms.

Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions, including display, evasion, photoprotection, detoxification, and metal scavenging. To date, evidence of melanin in fossil organisms has relied entirely on indirect morphological and chemical analyses. Here, we apply direct chemical techniques to categorically demonstrate the preservation of eumelanin in two > 160 Ma Jurassic cephalopod ink sacs and to confirm its chemical similarity to the ink of the modern cephalopod, Sepia officinalis. Identification and characterization of degradation-resistant melanin may provide insights into its diverse roles in ancient organisms., NASA Astrobiology Institute (Grant)