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The design of a relational database for ichnological data is presented to illustrate and address deficiencies in present-day palaeontological databases. Currently, palaeontology databases apply concepts and terminology derived from the study of body fossils to trace fossil records. We suggest that fundamental differences between body and trace fossils make this practice inappropriate. These differences stem from the fact that trace fossils represent the behaviour of the tracemaker, and not the phylogenetic affinities of an organism. This database, referred to as IchnoDB, has been tested by the authors throughout the design process to ensure that recommended alterations to current palaeontology databases made herein are functional. In describing the design and logic that underpins an ichnology database, it is our desire to see established palaeontological databases incorporate ichnology specific fields into their structure. This would support and encourage future research, involving the use of large ichnological datasets. [ABSTRACT FROM AUTHOR]

The timing of recovery after the end‐Permian mass extinction has been a matter of debate, with some authors favouring a more rapid faunal recovery during the Early Triassic and others considering a more protracted biotic reestablishment spanning until the Middle Triassic. In this work, we investigated the lowermost Middle Triassic (Ladinian) carbonate deposits in the Catalan Basin to evaluate the potential environmental mechanisms and evolutionary constrains involved in the kilometre‐scale predominance of microbialites and the low‐diversity and high‐density Planolites association in a low‐latitude epicontinental setting. The studied sedimentary succession records the development from a low‐gradient, homoclinal microbial‐dominated carbonate ramp evolving towards a slightly inclined swell‐dominated type. Sedimentological analysis suggests that facies heterogeneity was controlled by pulses of syn‐rift tectonic activity, which compromised Peri‐Tethyan basin connectivity, reducing palaeobathymetry gradients. Although the monospecific nature of the studied trace‐fossil association may reflect the delayed recovery after the end‐Permian mass extinction, this is inconsistent with widespread, relatively high‐diversity ichnofaunas in carbonates elsewhere in the region. Since other Ladinian basins were characterized by the recurrence of microbial carbonates, low‐diversity ichnoassemblages and limited skeletal production, we hypothesize that shallow and restricted carbonate ramp settings harboured limited ecological complexity and widespread opportunistic colonization of the sediment when compared to coeval open marine locations. [ABSTRACT FROM AUTHOR]

The end-Permian mass extinction (EPME) profoundly shaped shallow marine ecosystems. Although much has been learned about this event based on the body-fossil record, the global infaunal response to the EPME, as represented by ichnofossils, is much less understood. Here we analyze secular changes in ichnodiversity and ichnodisparity from the late Permian to the Middle Triassic based on a global trace-fossil data set. Results show that, in contrast to the body-fossil record, late Permian global ichnodiversity and ichnodisparity maintained their level until the Griesbachian, followed by a sharp loss in the Dienerian. Notably, the Griesbachian shows an unusual dominance of shallower tiers. The discrepancy between the body- and tracefossil record is interpreted to be the result of the resurgence of widespread microbial matgrounds in the Griesbachian that aided the preservation of surface, semi-infaunal, and shallow-tier ichnofossils. Our study shows that the EPME strongly affected the sediment mixed layer, allowing the preservation of shallower tier trace fossils. The disappearance of the mixed layer in the earliest Triassic may have enhanced pyrite burial in sediments and inhibited its further re-oxidation, therefore impacting sea water sulfate concentrations. [ABSTRACT FROM AUTHOR]

The ichnospecies Nummipera eocenica occurs in thick-bedded, tabular bioclastic massive sandstone of the upper Eocene San Jacinto Formation in the San Jacinto Fold Belt Basin, Colombia. Nummipera eocenica is a vertical to oblique burrow locally displaying a conical shape. The lining structure of the specimens studied consists of uniformly distributed lepidocyclinids and operculinids, with tests typically dipping towards the burrow wall, and well-compacted lining. The burrow infill is identical to the host rock, a bioclastic sandstone with abundant bivalve fragments. The diagnosis of Nummipera is emended to include as components of burrow lining all representatives of the Subclass Rotaliana characterized by being lenticular to discoidal in shape. In the San Jacinto Formation, Nummipera eocenica is present in the transition between deltaic mouth-bar and carbonate platform deposits. [ABSTRACT FROM AUTHOR]

The lower Paleozoic marine siliciclastic succession of the Central Andean Basin, northwestern Argentina, provides a valuable record of the onset of the Great Ordovician Biodiversification Event in western Gondwana. A new ichnospecies of rosette trace fossil, Gyrophyllites cristinae, is documented from lower and upper Tremadocian (Tr1 and Tr2) deposits of this basin. It is characterized by five to six non-overlapping petaloid lobes and can be easily differentiated from the other four formally defined ichnospecies. Gyrophyllites cristinae occurs at the top of hummocky cross-stratified sandstone regularly interbedded with mudstone. These deposits are interpreted as reflecting the alternation of high-energy storm events and low-energy fair-weather conditions immediately below the fair-weather wave base, representing deposition in offshore transition environments. Gyrophyllites has been traditionally interpreted as the product of worms of uncertain taxonomic affinity that mined the sediment in search for food (fodinichnia). The occurrence of Gyrophyllites cristinae in these Ordovician deposits records post-storm colonization. Storms may have increased oxygenation and supplied fresh organic detritus that were exploited by worm-like, surface detritus- or shallow deposit-feeders exploring the uppermost silt-rich fine-grained sediments. [ABSTRACT FROM AUTHOR]

Abstract The upper Campanian Dinosaur Park Formation (DPF) is a south- and eastward-thinning fluvial to marginal-marine clastic wedge in the Western Canadian Sedimentary Basin. The DPF is overlain by the Bearpaw Formation (BF), a fully marine clastic succession representing the final major transgression of this epicontinental sea across western North America. In southwestern Saskatchewan, the DPF is comprised of marginal-marine coal, carbonaceous shale, and heterolithic siltstone and sandstone grading vertically into marine sandstone and shale of the BF. Historically these deposits have been interpreted as the record of fluvial delta systems along a paleocoastline. This study revisits this interpretation using integration of ichnologic, sedimentologic, and sequence stratigraphic concepts. Detailed facies analysis indicates the upper DPF does not record sedimentation in a delta system, but rather was deposited in a low-relief coastal plain with a wave-dominated, tidally influenced, fluvially modified shoreline. Marginal-marine facies, interpreted as lagoons, tidal flats and estuaries, are bioturbated, showing a typical brackish-water trace-fossil assemblage, including Asterosoma isp., Chondrites isp., Cylindrichnus concentricus , Teichichnus rectus , and Skolithos isp. Fine-grained sandstone was deposited in an estuarine mouth-bar and barrier-island complex that protected the coast from wave reworking. As the seaway transgressed across the coast, fully marine wave-dominated parasequences replaced those of the coastal plain. Typical trace fossils include Asterosoma isp., Chondrites isp., Diplocraterion isp., Nereites missouriensis , Phycosiphon incertum, Planolites isp., Rhizocorallium isp., and Zoophycos isp., reflecting open, fully marine conditions. This study provides new insights into the evolution of depositional environments in the Late Cretaceous of southwestern Saskatchewan, and provides a framework for further geological and paleontological studies ongoing in the region. Highlights • Characterization of the Dinosaur Park – Bearpaw Formation transgression in southwestern Saskatchewan. • Identification of the controlling depositional processes during transgression. • Discussion of the paleoenvironmental evolution of the region under study. • Highlighting the significance of ichnologic data in interpreting processes and environments. • Characterization of anoxia/euxinia in the Western Interior Seaway as indicated by trace fossil associations. [ABSTRACT FROM AUTHOR]

Evidence for macroscopic life in the Paleoproterozoic Era comes from 1.8 billion-year-old (Ga) compression fossils [Han TM, Runnegar B (1992) Science 257:232-235; Knoll et al. (2006) Philos Trans R Soc Lond B 361:1023-1038], Stirling biota [Bengtson S et al. (2007) Paleobiology 33:351-381], and large colonial organisms exhibiting signs of coordinated growth from the 2.1-Ga Francevillian series, Gabon. Here we report on pyritized string-shaped structures from the Francevillian Basin. Combined microscopic, microtomographic, geochemical, and sedimentologic analyses provide evidence for biogenicity, and syngenicity and suggest that the structures underwent fossilization during early diagenesis close to the sediment-water interface. The string-shaped structures are up to 6 mm across and extend up to 170 mm through the strata. Morphological and 3D tomographic reconstructions suggest that the producer may have been a multicellular or syncytial organism able to migrate laterally and vertically to reach food resources. A possible modern analog is the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds at times of starvation. This unique ecologic window established in an oxygenated, shallow-marine environment represents an exceptional record of the biosphere following the crucial changes that occurred in the atmosphere and ocean in the aftermath of the great oxidation event (GOE). [ABSTRACT FROM AUTHOR]

Abstract The Middle Jurassic Lajas Formation of the Neuquén Basin (Argentina) records mainly deltaic sedimentation. However, the precise role of the depositional mechanisms involved is still controversial. Well core YPF Nq. Laj-8 records the overall vertical transition from delta-front mouth bars to delta plain. Discrete mouth-bar successions typically comprise a lower unbioturbated sandstone unit that passes upwards into a more intensely bioturbated sandstone unit. Phytodetrital material is abundant through the mouth-bar succession forming distinct layers in the lower units and becoming part of the lining of the burrow walls of Ophiomorpha irregulaire and Gyrolithes isp. in the upper units, representing two successive developmental stages of deltaic sandy mouth bars. Layers rich in phytodetritus exhibiting the same characteristics have been traditionally interpreted in outcrop as mudstone drapes generated by tidal action during slack-water periods. However, more recent research suggests that these layers can be best regarded as produced by river-fed flows, which is consistent with a river-dominated delta model. Highlights • Documentation of phytodetritus in distinct layers or on crustacean burrow walls • Interpretation of building stages of delta front mouth bars • Discussion of implications on dominant processes in deltaic systems [ABSTRACT FROM AUTHOR]

The continuous rise in hydrocarbon demand, the production decline in conventional oilfields, and the remarkable improvement in extraction methods have allowed the hydrocarbon industry and subsequently, geoscientists, to turn to studies on both unconventional and mature fields with untapped potential. In such reservoirs, the application of advanced drilling, completion, and production techniques must be preceded by the identification of permeable stratigraphic intervals that favour commercial exploitation. Accordingly, bioturbated deposits can play a key role in providing permeable pathways for enhanced production. Herein, we analyse the effects of bioturbation on the porosity and permeability of the Buda Formation, a highly bioturbated, tight (low-porosity matrix) Upper Cretaceous chalk reservoir from the Texas Gulf Coast Basin, which has been commercially exploited because of the occurrence of natural fractures. Our results show that (in addition to the natural fractures) burrows (and borings) substantially increased the porosity and permeability of this formation, thus, potentially contributing to enhanced hydrocarbon (or groundwater) storage and production. These biogenic structures might also have favoured the development of natural fractures and stylolites in the Buda Formation. However, further studies are required to prove this hypothesis. [ABSTRACT FROM AUTHOR]

Oxygen concentration in the ocean is vital for sustaining marine ecosystems. While the potential impacts of deoxygenation on modern oceans are hard to predict, lessons can be learned from better characterizing past geological intervals formed under a greenhouse climate. The greenhouse Cretaceous containing several oceanic anoxic events characterized by widespread oxygen‐deficient water is ideal in this regard. The Austin Chalk Group in south Texas (USA) shows organic‐rich intervals that can be linked to oxygen depletion in the ocean, but the exact bottom water oxygenation conditions have not been estimated. This study aims to reconstruct both sediment interstitial and bottom water oxygenation history during Austin Chalk Group deposition by integrating detailed ichnological, sedimentological and geochemical (X‐ray fluorescence and X‐ray diffraction) analyses, thereby providing a consistent model that may be applicable across a range of marine shelf settings. The 141.12 m Gise #1 core contains a continuous record of the Austin Chalk Group, providing an opportunity for unravelling oxygenation and deoxygenation events. Whereas the anaerobic–exaerobic deposits are essentially nonbioturbated, four oxygen‐related ichnocoenoses are defined, further refining the transition of aerobic to dysaerobic conditions in the sediment interstitial water. Omission surfaces and glauconitic grains, products of current‐induced scouring and condensation, suggest sporadic high‐energy events in the Austin Chalk Group ramp that drove elevated terrestrial inputs. Geochemical data further help to identify anoxic bottom water conditions within the anaerobic facies. Additionally, the lowermost part of the Austin Chalk Group illustrates redox cycles, whereas dilution events characterized by elevated terrestrial input are identified throughout the rest of the Austin Chalk Group. The evolution of oxygenation levels in sediment interstitial water and bottom water disputes the existence of a long‐lasting oxygen‐deficient sea in south Texas. The refined depositional model may be applicable to coeval shelfal settings. Moreover, the results provide insights into variable, evolving palaeoclimatic and palaeoceanographic conditions of the greenhouse Late Cretaceous. [ABSTRACT FROM AUTHOR]