Luis A. Buatois

Luis A. Buatois
University of Saskatchewan | U of S · Department of Geological Sciences

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386
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Introduction

Publications

Publications (386)
Book
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Until very recently, the early Alpine Permian-Triassic tectono-sedimentary phases preserved in the Cantabrian Mountains have suffered from important stratigraphic mismatches and wrong tectonics interpretations. The lack of precise ages and misunderstanding of the stratigraphical units were the main causes behind these problems. In consequence, the...
Article
Contourites are increasingly being recognized in ancient fine-grained depositional environments. However, detailed ichnologic analyses focusing on shallow-water examples of these deposits are scarce. The Upper Jurassic–Lower Cretaceous Vaca Muerta Formation from Argentina constitutes an important unconventional reservoir that displays dm- to m-thic...
Article
Synopsis The invasion of the land was a complex, protracted process, punctuated by mass extinctions, that involved multiple routes from marine environments. We integrate paleobiology, ichnology, sedimentology, and geomorphology to reconstruct Paleozoic terrestrialization. Cambrian landscapes were dominated by laterally mobile rivers with unstable b...
Article
Over the last few years, recognition and characterization of sedimentary processes in fine-grained successions is receiving considerable attention in part due to the increased importance of unconventional reservoirs. Recent sedimentologic analyses of these successions have revealed abundant traction transport structures that suggest bottom current...
Article
Changes in diversity of trace fossils through time provide information about evolutionary innovations in animal‐substrate interactions. Global ichnodiversity changes at ichnogeneric rank are useful to capture major trends, but may be insufficient to reveal minor behavioural innovations. A quantitative analysis of ichnodiversity trajectories at ichn...
Article
Infaunalization has been regarded as representing a response to increased predation pressures and is therefore central to the Mesozoic marine revolution, which gives pre-eminence to the role that enemy-directed evolution has played as a driving force of biotic change. Our ichnologic compilation from 39 Middle Triassic to Late Jurassic shallow-marin...
Article
The Cenomanian Buda Limestone is a distinctive rock formation widely distributed in Texas and its neighboring regions. The extensive character and regional significance of this unit make the Buda Limestone a key stratigraphic datum in the Texas Gulf Coast Basin. Detailed sedimentologic and stratigraphic studies of this formation were mostly focused...
Article
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Spiral burrows perpendicular to the bedding plane are well known in the fossil record and are usually referred to the ichnogenus Gyrolithes. Common in Mesozoic and Cenozoic marginal-marine, brackish-water deposits, the only records of Gyrolithes in Paleozoic rocks are from the Cambrian. In Permian rocks of the Paraná Basin (Rio do Sul and Rio Bonit...
Article
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The Chengjiang Biota is the earliest Phanerozoic soft-bodied fossil assemblage offering the most complete snapshot of Earth's initial diversification, the Cambrian Explosion. Although palaeobiologic aspects of this biota are well understood, the precise sedimentary environment inhabited by this biota remains debated. Herein, we examine a non-weathe...
Article
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The Early Ordovician is a key interval for our understanding of the evolution of life on Earth as it lays at the transition between the Cambrian Explosion and the Ordovician Radiation and because the fossil record of the late Cambrian is scarce. In this study, assembly processes of Early Ordovician trilobite and echinoderm communities from the Cent...
Article
Taphrhelminthopsis was originally introduced for trace fossils with a bilobate lower surface recorded in post-Paleozoic deep-marine deposits but has more recently been reinterpreted convincingly as a preservational variant of Scolicia. However, Taphrhelminthopsis has also been used for Cambrian shallow-marine trace fossils, whose taxonomic affinity...
Conference Paper
Full-text available
Bottom currents induced by thermohaline-, wind-, or tide-driven circulation may occur in shallow waters (50-300 m water depths), such as in outer shelves, upper slopes and shallow sills. The Upper Jurassic-Lower Cretaceous Vaca Muerta Formation in Argentina shows drift deposits located in bottomsets and foresets of a mixed carbonate-siliciclastic,...
Conference Paper
Full-text available
The Chapel Island Formation (CIF) at the Burin Peninsula, Newfoundland, Canada, is a 1000+ m-thick siliciclastic succession that hosts the Cambrian GSSP (ca. 541 Ma) 2.4 m above the base of its member 2 (M2) at Fortune Head. In this section, the first appearance of Treptichnus pedum, the index fossil for the base of the Cambrian, but also of other...
Conference Paper
Full-text available
The Chapel Island Formation (CIF) of Newfoundland, Canada, is a 1000+ m-thick siliciclastic succession that hosts the Cambrian GSSP (ca. 541 Ma) 2.4 m above the base of its member 2 (M2) in Fortune Head. Although the first appearance of Treptichnus pedum was considered as the marker of the base of the Cambrian, other burrows typical of the Fortunia...
Article
This study documents the distribution of matgrounds in a wide variety of environments recorded in the Ordovician Lashkerak and Ghelli Formations in the Alborz Mountains of northern Iran in order to evaluate controls on their distribution along the marine depositional profile. Detailed facies analysis allowed differentiating three groups of facies a...
Article
The ichnogenera Syringomorpha and Daedalus are here interpreted as products of infaunal biofilm harvesters. This study investigated: (1) Syringomorpha nilssoni and Syringomorpha isp. from the Cambrian Series 2‐Miaolingian Campanario Formation, northwest Argentina; and (2) Daedalus halli from the Floian Grès et Schistes de la Cluse de l'Orb Formatio...
Article
La Formación Mojotoro (Ordovícico Inferior a Medio, Salta, noroeste de Argentina) comprende potentes paquetes de cuarcitas intercaladas con facies heterolíticas, registrando sedimentaci6n en un ambiente litoral a marino somero dominado por mareas. Los ambientes sedimentarios incluyen complejos de ondas de arena submareales, zonas de interbarra, már...
Article
Understanding the functioning of extinct ecosystems is a complicated knot of ecological, evolutionary, and preservational strands that must be untangled. For instance, anatomical and behavioral differences can profoundly alter fossilization pathways. This is particularly true in exceptionally preserved soft-bodied biotas that record the earliest ph...
Article
The Cenomanian Buda Limestone is a widespread coccolith-rich carbonate unit deposited on the Comanche Shelf of the Texas Gulf Coast Basin. This formation is a key stratigraphic marker, and its hydrocarbon resources have been exploited since the 1920s. Despite its stratigraphic and economic importance, the depositional environments, and controls on...
Article
Although the middle Miocene Oficina Formation of the Orinoco Oil Belt represents most of Venezuela's hydrocarbon resource, a comprehensive and detailed sedimentary facies model for the whole belt has never been put forward. Based on the analysis of cores and well logs, nine sedimentary facies (FA-I), forming five facies assemblages (FA1-5), have be...
Article
Full-text available
Benthic animals profoundly influence the cycling and storage of carbon and other elements in marine systems, particularly in coastal sediments. Recent climate change has altered the distribution and abundance of many seafloor taxa and modified the vertical exchange of materials between ocean and sediment layers. Here, we examine how climate change...
Article
Full-text available
The exceptionally preserved fossils entombed in the deposits of sediment-gravity flows in the Cambrian Burgess Shale of British Columbia have been fundamental for understanding the origin of major animal groups during the Cambrian explosion. More recently, they have been used to investigate the evolution of community structure; however, this assume...
Article
We report the results of a multidisciplinary study of the early Permian (Artinskian–Kungurian) Sotres Formation of northern Spain integrating sedimentology, palaeosols, mineralogy, stable isotopes, palynology, ichnology and tectonics. This continental unit was deposited in the near-equatorial Peri-Tethyan Cantabrian Basin. Having developed in the m...
Article
The Upper Cretaceous M2 and U Sandstone members of the Napo Formation are prolific hydrocarbon producers in the Oriente Basin of eastern Ecuador. To understand the depositional origin of these reservoirs, an integrated sedimentologic, sequence-stratigraphic, and ichnologic study, using 490 ft (∼149 m) of conventional core from six wells of oil fiel...
Chapter
Modern Lake Magadi and Nasikie Engida in the inner southern Kenya Rift exemplify the extreme conditions in some continental rift settings, with abundant inflow from hot springs and magmatic CO2, producing high-carbonate-bicarbonate, high-sodium waters with little calcium in a semi-arid closed lake basin. Hypersalinity, hyperalkalinity, and hydrothe...
Article
The Capitanian (late middle Permian) and end‐Permian mass extinctions were particularly severe from a palaeoecological perspective. Previous studies of their expressions on land underscored their impacts on plants and vertebrates, but the effects on the continental invertebrate infauna remain poorly understood. A multiproxy analysis from the Iberia...
Article
Considering the evolution of aeolian to marine transitions for the geological record, either catastrophic or gradual transgressive scenarios showing high or low rates of coastal migration have been proposed. A critical evaluation of modern analogues suggests that a catastrophic transgression shares many characteristics with Holocene transgressions,...
Article
Trilobites, key components of early Palaeozoic communities, are considered to have been invariably fully marine. Through the integration of ichnological, palaeobiological, and sedimentological datasets within a sequence-stratigraphical framework, we challenge this assumption. Here, we report uncontroversial trace and body fossil evidence of their p...
Article
The Miocene Pirabas Formation is of strategic importance for the hydrocarbon industry since it represents the onshore portion of larger offshore basins of Northern Brazil, including the Fóz de Amazonas, the Pará-Maranhão, Barreirinhas, Ceará, and the Potiguar basins of the equatorial margin of South America. The Pirabas Formation from the Aricuru o...
Article
Full-text available
The Aptian evaporitic transitional sequence (sag phase) of the Brazilian marginal basins records the first connection between the Central and South Atlantic oceans in the equatorial area. During this phase, lacustrine carbonate reservoirs and giant salt deposits developed in the southern basins of Santos and Campos, forming world‐class petroleum re...
Article
Widespread oceanic anoxia has been implicated as a killing mechanism during the end-Permian mass extinction (EPME). A high-resolution investigation of pyrite framboids and bioturbation structures in the Shangsi section of South China has revealed repeated and frequent fluctuations of coupled anoxic/euxinic to dysoxic/oxic episodes in the latest Per...
Article
Full-text available
The Ediacaran–Cambrian transition marks one of the most important geobiological revolutions in Earth History, including multiple waves of evolutionary radiation and successive episodes of apparent mass extinction. Among the proposed drivers of these events (in particular the extinction of the latest Neoproterozoic ‘Ediacara biota’) is the emergence...
Article
Luancaia igen. Nov. and its two new ichnospecies, L. candasensis and L. elongata, from the Middle Devonian Naranco Formation of Asturias, northern Spain, record infaunal moulting most likely related to a defensive strategy. The new ichnogenus has an elongate to oblong outline, and displays a distinctly trilobate appearance that includes an axial lo...
Article
The trace-fossil record provides a wealth of information to track the rise and early evolution of animals. It comprises the activity of both hard- and soft-bodied organisms, is continuous through the Ediacaran (635–539 Ma)– Cambrian (539–485 Ma) transition, yields insights into animal behaviour and their role as ecosystem engineers, and allows for...
Article
The Oligocene Lower Freshwater Molasse of Switzerland is host to spectacular outcrops of fluvial deposits. In distal areas of the Swiss Molasse Basin, deposits of a north-eastward draining meandering system are exposed. Combined sedimentologic and ichnologic observations in the Chli Sunnhalde and Roggwil quarries allow an improved understanding of...
Article
Full-text available
The Cambrian explosion (CE) and the great Ordovician biodiversification event (GOBE) are the two most important radiations in Paleozoic oceans. We quantify the role of bioturbation and bioerosion in ecospace utilization and ecosystem engineering using information from 1367 stratigraphic units. An increase in all diversity metrics is demonstrated fo...
Article
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 foss...
Article
The Campanian Belly River Group (BRG) is a nonmarine clastic cycle in the Western Canada Sedimentary Basin. In southern and central Alberta, the BRG has been subdivided in ascending order into the Foremost, Oldman, and Dinosaur Park formations based on distinctive lithologic, petrographic, and geometric characteristics. Regional surface and subsurf...
Article
Full-text available
The western Gondwana margin underwent a complex geodynamic history during the early Paleozoic, and major uncertainties remain as to the role of tectonism in sedimentary dynamics. This study focuses on the lower part Santa Rosita Formation and the coeval Guayoc Chico Group (Cordillera Oriental; Northwest Argentina), ranging from the late Cambrian (F...
Article
Full-text available
Despite the absence of metazoans, structures resembling animal traces are common in a soda lake from the western Brazil Pantanal wetland. Pantanal soda lakes are ecologically extreme environments that preclude complex life, allowing extremophiles to flourish. Direct observation indicates that these structures are pseudotraces, representing groove m...
Article
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 Per...
Article
The upper Valanginian – lower Aptian Centenario Formation is a significant producer of oil and gas in the Neuquén Basin, western Argentina. This formation is located exclusively in the subsurface of the eastern and northeastern Neuquén Basin, and is 450–1000 m thick. The Centenario Formation laterally interfingers with the Agrio Formation. Previous...
Article
Full-text available
Magadiite, a rare hydrous sodium-silicate mineral [NaSi7O13(OH)3·4(H2O)], was discovered about 50 years ago in sediments around Lake Magadi, a hypersaline alkaline lake fed by hot springs in the semi-arid southern Kenya Rift Valley. Today this harsh lacustrine environment excludes most organisms except microbial extremophiles, a few invertebrates (...
Article
Full-text available
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) carbon...
Article
Scolicia is one of the most conspicuous trace fossils in lower shoreface deposits of the Miocene Chenque Formation of Patagonia, Argentina. This ichnotaxon consists of horizontal, sinuous or meandering trace fossils with a laminated backfill and two parallel strings located at the base. Abundant body fossils attributed to Brisaster iheringi occur i...
Article
Full-text available
Trace fossils represent the primary source of information on the evolution of animal behaviour through deep time, and provide exceptional insights into complex life strategies that would be otherwise impossible to infer from the study of body parts alone. Here, we describe unusual trace fossils found in marginal-marine, storm- and river-flood depos...
Article
The Ediacaran–Cambrian transition was a time of marked biological and sedimentary changes, representing a significant evolutionary breakthrough in Earth’s history. Numerous explanations have been posited for these dramatic changes. One view emphasizes an extensive period of widespread continental denudation during the Neoproterozoic followed by ext...
Chapter
Seilacherian or archetypal ichnofacies are conceptual constructs based on the identification of key features shared by different ichnocoenoses of a wide range of ages and formed under a similar set of environmental conditions. Historically, the ichnofacies concept has been central in the transformation of ichnology from a marginal field to a discip...
Chapter
The term “Cambrian explosion” refers to an event in the history of the biosphere when the vast majority of metazoan phyla that populate the Earth today first appeared in the fossil record. Historically, there have been two opposing ways of assessing the Cambrian explosion. One line of thought highlights the merits of the fossil record as a reliable...
Article
Trace fossils represent records of the activity of both epifaunal and infaunal animals, providing significant information for a deeper understanding of Earth’s past environments and ecosystems. Increasingly, more and more ichno-metrics (quantitative ichnological indicators) have been proposed and applied to critical geological intervals as a method...
Article
Full-text available
The distribution of trace-making organisms in coastal settings is largely controlled by changes in physicochemical parameters, which in turn are a response to different climatic and oceanographic conditions. The trace fossil Macaronichnus and its modern producers are typical of high-energy, siliciclastic foreshore sands in intermediate- to high-lat...
Conference Paper
Full-text available
The Cambrian GSSP (ca. 540 Ma) is marked by the appearance of complex trace fossil from the Treptichnus pedum Ichnofossil Assemblage Zone in the Chapel Island Formation (CIF) at Fortune Head, Newfoundland in Canada (Brasier et al., 1994). The CIF is a 1000+ m-thick, mostly continuous siliciclastic succession that ranges from the late Ediacaran to C...
Article
Full-text available
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 distribute...
Article
Tide-influenced deposits of the Pennsylvanian Rock Lake Shale Member, Stanton Formation, Missouri and Kansas (U.S.A.), contain well-preserved evidence of the burrowing activities of protobranch bivalves, including locomotion (Protovirgularia) and locomotion-resting (Protovirgularia-Lockeia) trace fossils. Protovirgularia shows three distinct morpho...
Article
Modern burrowing organisms feed on microbial organic matter in matgrounds near hot springs on the margins of Lake Bogoria, a saline alkaline lake in the Kenya Rift Valley. The burrowers produce a low‐diversity trace assemblage similar to those produced by undermat miners during the Ediacaran–Cambrian transition. Despite obvious differences in body...
Article
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 Americ...
Article
The Upper Jurassic-Lower Cretaceous Vaca Muerta Formation at the Picún Leufú area constitutes bottomset and foreset marine deposits comprising open bay, siliciclastic basin and mixed carbonate-siliciclastic shelf facies. Detailed sedimentological, ichnological and sequence stratigraphic analysis of six stratigraphic sections allows establishing two...
Conference Paper
Full-text available
The mixed layer of modern oceans is a zone of fully homogenized sediment resulting from bioturbation (Berger et al., 1979; Teal et al., 2008). The mixed layer is host to complex biogeochemical cycles that directly impact ecosystem functioning, affecting ocean productivity and marine biodiversity. However, the timing of appearance of a mixed zone at...
Article
The Lower Cretaceous (Valanginian) Mulichinco Formation of the Neuquén Basin in western Argentina is host to important hydrocarbon reservoirs, encompassing a wide variety of sedimentary facies, including thick eolian deposits in its lower interval in proximal positions. Ten ichnofabrics are characterized based on the analysis of cores from the El M...
Article
Full-text available
The transition between the seemingly disparate Ediacaran and Cambrian faunas is both enigmatic and body-fossil poor. The Chapel Island Formation on the Burin Peninsula, Newfoundland, Canada, contains a rich diversity of ichnofossils, providing new insight into the nature of the Ediacaran-Cambrian transition and early Fortunian ecosystems. Five ichn...
Article
The fluvio-tidal transition zone (FTZ) is sedimentologically and ichnologically complex, encompassing variable sedimentary facies. Published research on the FTZ implies a wide range of physical and chemical conditions as well as resultant sedimentary structures. Variable definitions and terms have been applied to this transition zone for decades. T...
Article
Full-text available
Rocks of Ediacaran age (~635–541 Ma) contain the oldest fossils of large, complex organisms and their behaviors. These fossils document developmental and ecological innovations, and suggest that extinctions helped to shape the trajectory of early animal evolution. Conventional methods divide Ediacaran macrofossil localities into taxonomically disti...
Article
Full-text available
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 coordinat...
Article
Feeding trace fossils, produced by either deposit or detritus feeders and showing radial to rosetted morphology, are all included in the same architectural category. These radial to rosette ichnofossils are widely recorded worldwide throughout the Phanerozoic and have attracted the attention of numerous ichnologists for decades. Construction of a d...
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