Ana P. MORENO RODRÍGUEZ, N. Chimento, F. Agnolín, Guillermo Jofré, Adriel R Gentil
Abstract: Pleistocene large carnivores from the Pampean Region have been studied almost always based on bone remains. Here we report the first coprolite of a large carnivore from the Late Pleistocene of the Pampean Region, Argentina. The coprolite was found associated with megafauna bone remains and it shows the typical shape and size of a carnivorous mammal, with a length of 240 mm and a maximum diameter of 39.59 mm. The coprolite contains two bones of the autopodium of an artiodactyl, and numerous dermal ossicles of giant terrestrial sloths. The coprolite's composition, size, and shape allow us to discard ursids, canids, and small felids. Ursid and canid feces contain abundant plant remains, which are absent in the coprolite described here. Feces of extant felids are smaller than the coprolite here as they do not exceed 130 mm in length and 30 mm in diameter. Based on size, shape, and bone inclusions, the discovered coprolite may be attributed to the Machairodontinae saber-toothed felid Smilodon. If correctly identified, this coprolite sheds light on predatory habits of Smilodon.
{"title":"A POSSIBLE SMILODON (MAMMALIA, FELIDAE) COPROLITE FROM THE PLEISTOCENE OF ARGENTINA","authors":"Ana P. MORENO RODRÍGUEZ, N. Chimento, F. Agnolín, Guillermo Jofré, Adriel R Gentil","doi":"10.2110/palo.2021.056","DOIUrl":"https://doi.org/10.2110/palo.2021.056","url":null,"abstract":"Abstract: Pleistocene large carnivores from the Pampean Region have been studied almost always based on bone remains. Here we report the first coprolite of a large carnivore from the Late Pleistocene of the Pampean Region, Argentina. The coprolite was found associated with megafauna bone remains and it shows the typical shape and size of a carnivorous mammal, with a length of 240 mm and a maximum diameter of 39.59 mm. The coprolite contains two bones of the autopodium of an artiodactyl, and numerous dermal ossicles of giant terrestrial sloths. The coprolite's composition, size, and shape allow us to discard ursids, canids, and small felids. Ursid and canid feces contain abundant plant remains, which are absent in the coprolite described here. Feces of extant felids are smaller than the coprolite here as they do not exceed 130 mm in length and 30 mm in diameter. Based on size, shape, and bone inclusions, the discovered coprolite may be attributed to the Machairodontinae saber-toothed felid Smilodon. If correctly identified, this coprolite sheds light on predatory habits of Smilodon.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"402 - 410"},"PeriodicalIF":1.6,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46756411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vincent Caron, FRANÇOIS-XAVIER Joanny, J. Bailleul, Maxime Perot, F. Chanier, G. Mahieux
abstract: Taphonomic analysis is a useful tool to assess the intensity of alteration of skeletal remains and to help characterize depositional conditions as well as completeness and resolution of fossil assemblages. We herein introduce TAPHOGRAPH, an Excel spreadsheet script (a R code is also available), for the production of taphonomic diagrams to characterize the taphonomy of skeletal remains. The graphical representation depicts four taphonomic factors (fragmentation, abrasion, bioerosion, and encrustation) as a cumulative curve that allows visualization and comparison of the degree and variability of taphonomic alteration for different hard part types from one or more samples in a single diagram. The TAPHOGRAPH methodology is highly flexible, and can be used to assess the relative influence of mechanical versus biological (versus chemical) taphonomic alteration. The TAPHOGRAPH approach can guide inferences about hydraulic regimes, residence time at the seafloor, and intensity of different taphonomic processes.
{"title":"TAPHOGRAPH: A SPREADSHEET METHOD TO GRAPHICALLY CHARACTERIZE THE TAPHONOMY OF SKELETAL PARTICLES","authors":"Vincent Caron, FRANÇOIS-XAVIER Joanny, J. Bailleul, Maxime Perot, F. Chanier, G. Mahieux","doi":"10.2110/palo.2021.009","DOIUrl":"https://doi.org/10.2110/palo.2021.009","url":null,"abstract":"abstract: Taphonomic analysis is a useful tool to assess the intensity of alteration of skeletal remains and to help characterize depositional conditions as well as completeness and resolution of fossil assemblages. We herein introduce TAPHOGRAPH, an Excel spreadsheet script (a R code is also available), for the production of taphonomic diagrams to characterize the taphonomy of skeletal remains. The graphical representation depicts four taphonomic factors (fragmentation, abrasion, bioerosion, and encrustation) as a cumulative curve that allows visualization and comparison of the degree and variability of taphonomic alteration for different hard part types from one or more samples in a single diagram. The TAPHOGRAPH methodology is highly flexible, and can be used to assess the relative influence of mechanical versus biological (versus chemical) taphonomic alteration. The TAPHOGRAPH approach can guide inferences about hydraulic regimes, residence time at the seafloor, and intensity of different taphonomic processes.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"392 - 401"},"PeriodicalIF":1.6,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41373192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract: Palynological study of the Permian–Triassic boundary has typically focused on the pollen grain and spore content to reconstruct vegetation, with fungal remains either left unidentified or set aside for future research. Paleozoic fungal microfossil records in particular are lacking. The Zechstein Group (∼ 258–252 Ma; Lopingian) is a remarkable stratigraphic sequence of stacked carbonates and evaporites. High-resolution palynological analysis of new borehole cores through the Zechstein Group of northeast England has revealed its entire sedimentological history and enabled a new reconstruction of vegetation dynamics in central-western Europe preceding the Permian–Triassic boundary. Assemblages composed of conifers, pteridosperms, pteridophytes, sphenopsids, and cycads/ginkgoes were recovered alongside fungal remains throughout the entire sequence. Four fungal morphologies were observed, the most common being smooth-walled spheroidal inclusions of an endobiotic Chytridiomycota or Hypochytridiomycota affinity. Other evidence of fungi includes epiphytic Callimothallus-type fungi (Family Microthyraceae), the dematiaceous Chaetomium-like mold (Family Chaetomiaceae) found associated with soil, cellulose and plant debris, and possible evidence of chytrid-induced pitting on the surface of plant cuticle. This is the first study to highlight the fungal content of Zechstein palynological preparations and while occurrences are rare, they provide new insight into the composition of the Zechstein forest understory, reinforcing the interpretation that the upper Zechstein environment was humid. This work improves our understanding of the taxonomic and functional diversity of fungal taxa associated with evaporite systems during the Lopingian, and highlights the exceptional preservation potential of halite, combating underestimates of fungal richness in the fossil record.
{"title":"FIRST REPORT OF FUNGAL PALYNOMORPHS FROM THE ZECHSTEIN GROUP (LOPINGIAN): IMPLICATIONS FOR THE STRATIGRAPHIC COMPLETENESS OF THE EARTH'S PALEOZOIC FUNGAL RECORD","authors":"M. Gibson","doi":"10.2110/palo.2021.064","DOIUrl":"https://doi.org/10.2110/palo.2021.064","url":null,"abstract":"Abstract: Palynological study of the Permian–Triassic boundary has typically focused on the pollen grain and spore content to reconstruct vegetation, with fungal remains either left unidentified or set aside for future research. Paleozoic fungal microfossil records in particular are lacking. The Zechstein Group (∼ 258–252 Ma; Lopingian) is a remarkable stratigraphic sequence of stacked carbonates and evaporites. High-resolution palynological analysis of new borehole cores through the Zechstein Group of northeast England has revealed its entire sedimentological history and enabled a new reconstruction of vegetation dynamics in central-western Europe preceding the Permian–Triassic boundary. Assemblages composed of conifers, pteridosperms, pteridophytes, sphenopsids, and cycads/ginkgoes were recovered alongside fungal remains throughout the entire sequence. Four fungal morphologies were observed, the most common being smooth-walled spheroidal inclusions of an endobiotic Chytridiomycota or Hypochytridiomycota affinity. Other evidence of fungi includes epiphytic Callimothallus-type fungi (Family Microthyraceae), the dematiaceous Chaetomium-like mold (Family Chaetomiaceae) found associated with soil, cellulose and plant debris, and possible evidence of chytrid-induced pitting on the surface of plant cuticle. This is the first study to highlight the fungal content of Zechstein palynological preparations and while occurrences are rare, they provide new insight into the composition of the Zechstein forest understory, reinforcing the interpretation that the upper Zechstein environment was humid. This work improves our understanding of the taxonomic and functional diversity of fungal taxa associated with evaporite systems during the Lopingian, and highlights the exceptional preservation potential of halite, combating underestimates of fungal richness in the fossil record.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"318 - 329"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48167057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract: Wildfire has been implicated as a potential driver of deforestation and continental biodiversity loss during the end-Permian extinction event (EPE; ∼ 252 Ma). However, it cannot be established whether wildfire activity was anomalous during the EPE without valid pre- and post-EPE baselines. Here, we assess the changes in wildfire activity in the high-latitude lowlands of eastern Gondwana by presenting new long-term, quantitative late Permian (Lopingian) to Early Triassic records of dispersed fossil charcoal and inertinite from sediments of the Sydney Basin, eastern Australia. We also document little-transported fossil charcoal occurrences in middle to late Permian (Guadalupian to Lopingian) permineralized peats of the Lambert Graben, East Antarctica, and Sydney and Bowen basins, eastern Australia, indicating that even vegetation of consistently moist high-latitude settings was prone to regular fire events. Our records show that wildfires were consistently prevalent through the Lopingian, but the EPE demonstrates a clear spike in activity. The relatively low charcoal and inertinite baseline for the Early Triassic is likely due in part to the lower vegetation density, which would have limited fire spread. We review the evidence for middle Permian to Lower Triassic charcoal in the geosphere, and the impacts of wildfires on sedimentation processes and the evolution of landscapes. Moreover, we assess the evidence of continental extinction drivers during the EPE within eastern Australia, and critically evaluate the role of wildfires as a cause and consequence of ecosystem collapse. The initial intensification of the fire regime during the EPE likely played a role in the initial loss of wetland carbon sinks, and contributed to increased greenhouse gas emissions and land and freshwater ecosystem changes. However, we conclude that elevated wildfire frequency was a short-lived phenomenon; recurrent wildfire events were unlikely to be the direct cause of the subsequent long-term absence of peat-forming wetland vegetation, and the associated ‘coal gap’ of the Early Triassic.
{"title":"END-PERMIAN BURNOUT: THE ROLE OF PERMIAN–TRIASSIC WILDFIRES IN EXTINCTION, CARBON CYCLING, AND ENVIRONMENTAL CHANGE IN EASTERN GONDWANA","authors":"Christopher B Mays, S. McLoughlin","doi":"10.2110/palo.2021.051","DOIUrl":"https://doi.org/10.2110/palo.2021.051","url":null,"abstract":"Abstract: Wildfire has been implicated as a potential driver of deforestation and continental biodiversity loss during the end-Permian extinction event (EPE; ∼ 252 Ma). However, it cannot be established whether wildfire activity was anomalous during the EPE without valid pre- and post-EPE baselines. Here, we assess the changes in wildfire activity in the high-latitude lowlands of eastern Gondwana by presenting new long-term, quantitative late Permian (Lopingian) to Early Triassic records of dispersed fossil charcoal and inertinite from sediments of the Sydney Basin, eastern Australia. We also document little-transported fossil charcoal occurrences in middle to late Permian (Guadalupian to Lopingian) permineralized peats of the Lambert Graben, East Antarctica, and Sydney and Bowen basins, eastern Australia, indicating that even vegetation of consistently moist high-latitude settings was prone to regular fire events. Our records show that wildfires were consistently prevalent through the Lopingian, but the EPE demonstrates a clear spike in activity. The relatively low charcoal and inertinite baseline for the Early Triassic is likely due in part to the lower vegetation density, which would have limited fire spread. We review the evidence for middle Permian to Lower Triassic charcoal in the geosphere, and the impacts of wildfires on sedimentation processes and the evolution of landscapes. Moreover, we assess the evidence of continental extinction drivers during the EPE within eastern Australia, and critically evaluate the role of wildfires as a cause and consequence of ecosystem collapse. The initial intensification of the fire regime during the EPE likely played a role in the initial loss of wetland carbon sinks, and contributed to increased greenhouse gas emissions and land and freshwater ecosystem changes. However, we conclude that elevated wildfire frequency was a short-lived phenomenon; recurrent wildfire events were unlikely to be the direct cause of the subsequent long-term absence of peat-forming wetland vegetation, and the associated ‘coal gap’ of the Early Triassic.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"292 - 317"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42319946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Davies, J. Gosse, A. Rouillard, N. Rybczynski, Jin Meng, A. Reyes, Jarloo Kiguktak
Abstract: During the mid-Pliocene (Zanclean, ca. ∼ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–22°C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative strata. Paleoecological information from these strata provides a high-fidelity window onto Pliocene environments, and prominent fossil sites yield unparalleled insights into Cenozoic mammal evolution. Significantly, many of the strata reveal evidence for life-sediment interactions in a warm-climate Arctic, most notably in the form of extensive woody debris and phytoclast deposits. This paper presents original field data that refines the sedimentological context of plant debris accumulations from the anactualistic High Arctic forests, most notably at the ‘Fyles Leaf Beds’ and ‘Beaver Pond’ fossil-bearing sites in the ‘high terrace deposits’ of central Ellesmere Island. The former is a remarkably well-preserved, leaf-rich deposit that is part of a complex of facies associations representing lacustrine, fluvio-deltaic and mire deposition above a paleotopographic unconformity. The latter yields tooth-marked woody debris within a peat layer that also contains a rich assemblage of vertebrate and plant fossils including abundant remains from the extinct beaver-group Dipoides. Here we present sedimentological data that provide circumstantial evidence that the woody debris deposit at Beaver Pond could record dam-building in the genus, by comparing the facies motif with new data from known Holocene beaver dam facies in England. Across the Pliocene of the High Arctic region, woody debris accumulations are shown to represent an array of biosedimentary deposits and landforms including mires, driftcretions, woody bedforms, and possible beaver dams, which help to contextualize mammal fossil sites, provide facies models for high-latitude forests, and reveal interactions between life and sedimentation in a vanished world that may be an analogue to that of the near-future.
{"title":"WOOD JAMS OR BEAVER DAMS? PLIOCENE LIFE, SEDIMENT AND LANDSCAPE INTERACTIONS IN THE CANADIAN HIGH ARCTIC","authors":"N. Davies, J. Gosse, A. Rouillard, N. Rybczynski, Jin Meng, A. Reyes, Jarloo Kiguktak","doi":"10.2110/palo.2021.065","DOIUrl":"https://doi.org/10.2110/palo.2021.065","url":null,"abstract":"Abstract: During the mid-Pliocene (Zanclean, ca. ∼ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–22°C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative strata. Paleoecological information from these strata provides a high-fidelity window onto Pliocene environments, and prominent fossil sites yield unparalleled insights into Cenozoic mammal evolution. Significantly, many of the strata reveal evidence for life-sediment interactions in a warm-climate Arctic, most notably in the form of extensive woody debris and phytoclast deposits. This paper presents original field data that refines the sedimentological context of plant debris accumulations from the anactualistic High Arctic forests, most notably at the ‘Fyles Leaf Beds’ and ‘Beaver Pond’ fossil-bearing sites in the ‘high terrace deposits’ of central Ellesmere Island. The former is a remarkably well-preserved, leaf-rich deposit that is part of a complex of facies associations representing lacustrine, fluvio-deltaic and mire deposition above a paleotopographic unconformity. The latter yields tooth-marked woody debris within a peat layer that also contains a rich assemblage of vertebrate and plant fossils including abundant remains from the extinct beaver-group Dipoides. Here we present sedimentological data that provide circumstantial evidence that the woody debris deposit at Beaver Pond could record dam-building in the genus, by comparing the facies motif with new data from known Holocene beaver dam facies in England. Across the Pliocene of the High Arctic region, woody debris accumulations are shown to represent an array of biosedimentary deposits and landforms including mires, driftcretions, woody bedforms, and possible beaver dams, which help to contextualize mammal fossil sites, provide facies models for high-latitude forests, and reveal interactions between life and sedimentation in a vanished world that may be an analogue to that of the near-future.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"330 - 347"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47328563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Steffen Trümper, Václav Mencl, S. Opluštil, Sandra Niemirowska, Ronny Rößler
Abstract: By colonizing drylands, plants fundamentally changed continental deposition and, thus, intensified the interaction between life and sediments. Fossil large woody debris in epiclastic strata is a key archive of this environmental turnover, although its interpretation remains challenging due to taphonomic biases. We review voluminous fluvial red-bed successions with sizeable silicified trunks that characterize Middle Pennsylvanian–lower Permian strata of east-central Europe. The stratigraphic occurrence, petrography, architecture of the deposits, and the preservation and nature of the fossil wood are discussed in the context of the tectono-climatic and vegetational evolution of the central-Pangean low latitudes. The log-bearing successions are assigned to five distinct, regionally traceable stratigraphic levels between the middle Moscovian and early Asselian. Up to 20 m long, mostly decorticated trunk fragments occur isolated in more or less feldspathic channel deposits, the architectures and dimensions of which point to large-scale river systems with highly variable discharge. Wood anatomy and floodplain adpression-fossils show that the trunks were derived from cordaitaleans, conifers, and arborescent sphenopsids in more diverse, gymnosperm-dominated dryland floras. The fossil record is biased towards successions formed in large-catchment river systems and, thus, does not accurately document the genuine nature of plant-distribution patterns. Rather, the strata show that large woody debris preservation depended on fluvial style and hydrological regime, hence turning the woody deposits into climate archives. The strata elucidate the climate development in equatorial Pangea, paralleling the acme of the Late Paleozoic Ice Age.
{"title":"LARGE WOODY DEBRIS ACCUMULATIONS IN THE LATE PENNSYLVANIAN TROPICS—EVOLUTIONARY SIGNAL OR TECTONO-CLIMATIC ARCHIVE?","authors":"Steffen Trümper, Václav Mencl, S. Opluštil, Sandra Niemirowska, Ronny Rößler","doi":"10.2110/palo.2022.003","DOIUrl":"https://doi.org/10.2110/palo.2022.003","url":null,"abstract":"Abstract: By colonizing drylands, plants fundamentally changed continental deposition and, thus, intensified the interaction between life and sediments. Fossil large woody debris in epiclastic strata is a key archive of this environmental turnover, although its interpretation remains challenging due to taphonomic biases. We review voluminous fluvial red-bed successions with sizeable silicified trunks that characterize Middle Pennsylvanian–lower Permian strata of east-central Europe. The stratigraphic occurrence, petrography, architecture of the deposits, and the preservation and nature of the fossil wood are discussed in the context of the tectono-climatic and vegetational evolution of the central-Pangean low latitudes. The log-bearing successions are assigned to five distinct, regionally traceable stratigraphic levels between the middle Moscovian and early Asselian. Up to 20 m long, mostly decorticated trunk fragments occur isolated in more or less feldspathic channel deposits, the architectures and dimensions of which point to large-scale river systems with highly variable discharge. Wood anatomy and floodplain adpression-fossils show that the trunks were derived from cordaitaleans, conifers, and arborescent sphenopsids in more diverse, gymnosperm-dominated dryland floras. The fossil record is biased towards successions formed in large-catchment river systems and, thus, does not accurately document the genuine nature of plant-distribution patterns. Rather, the strata show that large woody debris preservation depended on fluvial style and hydrological regime, hence turning the woody deposits into climate archives. The strata elucidate the climate development in equatorial Pangea, paralleling the acme of the Late Paleozoic Ice Age.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"251 - 291"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46971865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Davies, W. McMahon, Anthony P. Shillito, Ben J. Slater
Amongst all the disciplines in Earth Sciences, paleontology and sedimentary geology share a particularly striking and complicated frontier. On the one hand, some of the topics that they encompass are apparently separated by huge gulfs in methods and expertise: multiple degrees of separation need to be counted to get from, say, molecular phylogeny to sediment diagenesis, or paleophysiology to sequence stratigraphy. Yet there are arguably further areas where the boundary between the subjects is far more porous, consisting of sub-disciplines that refuse to be pigeon-holed and instead demand consensus between paleontologists and sedimentary geologists. This hazy border zone is the natural territory of PALAIOS, the remit of which is to emphasize ‘‘ the impact of life on Earth’s history as recorded in the paleontological and sedimentological records ’’ , and which has previously published seminal advances in topics such as ichnology, taphonomy, and carbonate sedimentology. Recognizing this, this first of two thematic sets in the journal, which seek to explore how the sedimentary rock record has chronicled ancient life and sediment interactions, might seem unnecessary. Yet what makes these collected papers distinct is that they defy classification within any particular sub-discipline: rather these are either ‘paleontological’ papers that pay additional attention to sedimentological context or ‘sedimentological’ papers that emphasize the importance of life in sedimentary environments. In each instance they demonstrate the potential to understand much more
{"title":"DEEP TIME BIOGEOMORPHOLOGY: THE CO-EVOLUTION OF LIFE AND SEDIMENTS","authors":"N. Davies, W. McMahon, Anthony P. Shillito, Ben J. Slater","doi":"10.2110/palo.2022.029","DOIUrl":"https://doi.org/10.2110/palo.2022.029","url":null,"abstract":"Amongst all the disciplines in Earth Sciences, paleontology and sedimentary geology share a particularly striking and complicated frontier. On the one hand, some of the topics that they encompass are apparently separated by huge gulfs in methods and expertise: multiple degrees of separation need to be counted to get from, say, molecular phylogeny to sediment diagenesis, or paleophysiology to sequence stratigraphy. Yet there are arguably further areas where the boundary between the subjects is far more porous, consisting of sub-disciplines that refuse to be pigeon-holed and instead demand consensus between paleontologists and sedimentary geologists. This hazy border zone is the natural territory of PALAIOS, the remit of which is to emphasize ‘‘ the impact of life on Earth’s history as recorded in the paleontological and sedimentological records ’’ , and which has previously published seminal advances in topics such as ichnology, taphonomy, and carbonate sedimentology. Recognizing this, this first of two thematic sets in the journal, which seek to explore how the sedimentary rock record has chronicled ancient life and sediment interactions, might seem unnecessary. Yet what makes these collected papers distinct is that they defy classification within any particular sub-discipline: rather these are either ‘paleontological’ papers that pay additional attention to sedimentological context or ‘sedimentological’ papers that emphasize the importance of life in sedimentary environments. In each instance they demonstrate the potential to understand much more","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"219 - 223"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43230831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. McMahon, H. Pierik, Anthony P. Shillito, F. Salese, Bart Van Der Kwaak, D. Parsons, M. Kleinhans
Abstract: The sedimentary-stratigraphic record is regularly considered only in the context of regional climate, tectonic configuration, and sea-level. In this study we provide examples of how biotically influenced autogenic processes may come to be overprinted on these extrinsic, allogenic controls. A sedimentological analysis is given for the Mississippian (Visean) siliciclastic strata which crop out in counties Donegal and Mayo in NW Ireland. Eleven sedimentary facies record deposition of dominantly clastic and humic organic sediments which accumulated in alluvial, fluvial, estuarine, and fully marine environments. The preserved architecture of the sedimentary deposits is shown to be dependent on local autogenic dynamics, processes that were in turn modified or entirely controlled by biota (“biosphere signatures”). Sedimentological criteria, specifically the type and distribution of preserved biosphere signatures, suggests deposition occurred in a dominantly wet, humid environment in keeping with Laurussia's proposed equatorial position but potentially at odds with previous suggestions of seasonal aridity. The humid climate and resultant perennially active water conduits facilitated the widespread preservation of inclined heterolithic stratification (IHS). Allogenic and autogenic processes are ultimately linked, with external factors such as sea-level, tectonics, and climate all impacting the spatial distribution, abundance and prevailing forms of biota. The flooding of the Laurussian continent is accompanied by a shift from plant-induced to animal-induced biosphere signatures basinwards of the estuary funnel. In this way, the interplay between allogenic and autogenic processes is recorded at sedimentary outcrop through the capacity of extrinsic forcings to influence the rates and locations of intrinsic life-sediment interactions.
{"title":"SUPERIMPOSED ALLOGENIC AND BIOLOGICAL CONTROLS ON SILICICLASTIC ARCHITECTURE: AN EARLY MISSISSIPPIAN (VISEAN) EXAMPLE FROM TROPICAL LAURUSSIA","authors":"W. McMahon, H. Pierik, Anthony P. Shillito, F. Salese, Bart Van Der Kwaak, D. Parsons, M. Kleinhans","doi":"10.2110/palo.2021.033","DOIUrl":"https://doi.org/10.2110/palo.2021.033","url":null,"abstract":"Abstract: The sedimentary-stratigraphic record is regularly considered only in the context of regional climate, tectonic configuration, and sea-level. In this study we provide examples of how biotically influenced autogenic processes may come to be overprinted on these extrinsic, allogenic controls. A sedimentological analysis is given for the Mississippian (Visean) siliciclastic strata which crop out in counties Donegal and Mayo in NW Ireland. Eleven sedimentary facies record deposition of dominantly clastic and humic organic sediments which accumulated in alluvial, fluvial, estuarine, and fully marine environments. The preserved architecture of the sedimentary deposits is shown to be dependent on local autogenic dynamics, processes that were in turn modified or entirely controlled by biota (“biosphere signatures”). Sedimentological criteria, specifically the type and distribution of preserved biosphere signatures, suggests deposition occurred in a dominantly wet, humid environment in keeping with Laurussia's proposed equatorial position but potentially at odds with previous suggestions of seasonal aridity. The humid climate and resultant perennially active water conduits facilitated the widespread preservation of inclined heterolithic stratification (IHS). Allogenic and autogenic processes are ultimately linked, with external factors such as sea-level, tectonics, and climate all impacting the spatial distribution, abundance and prevailing forms of biota. The flooding of the Laurussian continent is accompanied by a shift from plant-induced to animal-induced biosphere signatures basinwards of the estuary funnel. In this way, the interplay between allogenic and autogenic processes is recorded at sedimentary outcrop through the capacity of extrinsic forcings to influence the rates and locations of intrinsic life-sediment interactions.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"224 - 250"},"PeriodicalIF":1.6,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49201423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Paz, M. Mángano, L. Buatois, P. Desjardins, Raúl Notta, Federico Tomassini, N. Carmona
Abstract: 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-thick, laminated, rippled and bioturbated, crinoidal mudstone and fine to coarse mudstone deposited by wind- and thermohaline-driven contour currents. Four ichnofabrics were recognized in three facies associations. The Palaeophycus heberti ichnofabric is dominant in facies association 1, forming highly bioturbated intervals. The Palaeophycus heberti, Nereites isp., and Phycosiphon incertum ichnofabrics are present in facies association 2, displaying highly, moderately and sparsely bioturbated intervals, respectively. This association is locally characterized by m-thick successions comprising an upward decrease and then increase in bioturbation index, which may have a similar origin to bigradational sequences. The Equilibrichnia-Fugichnia ichnofabric mostly occurs in facies association 3 and less commonly in 2, forming distinctive bioturbated intervals within sparsely bioturbated successions. Benthic activity was controlled by food distribution, oxygenation, hydrodynamic energy, and water turbidity. Food was delivered to the surface or in suspension by currents, promoting deposit- or suspension-feeding strategies in the infauna, respectively. Oxygen levels increased during contour current activity yet remained relatively low (upper dysoxic). Hydrodynamic energy controlled bioturbation intensity, resulting in lower degrees of bioturbation during higher energy events. Suspension-feeding strategies suggest that water turbidity was relatively low during current transport. The herein example increases our understanding of environmental controls of shallow-water contour currents, supporting the fact that high bioturbation levels are typical of contourite deposits and providing an example of muddy contourites showing high preservation of sedimentary structures due to oxygen deficiency in bottom waters.
{"title":"ICHNOLOGY OF MUDDY SHALLOW-WATER CONTOURITES FROM THE UPPER JURASSIC–LOWER CRETACEOUS VACA MUERTA FORMATION, ARGENTINA: IMPLICATIONS FOR TRACE-FOSSIL MODELS","authors":"M. Paz, M. Mángano, L. Buatois, P. Desjardins, Raúl Notta, Federico Tomassini, N. Carmona","doi":"10.2110/palo.2020.028","DOIUrl":"https://doi.org/10.2110/palo.2020.028","url":null,"abstract":"Abstract: 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-thick, laminated, rippled and bioturbated, crinoidal mudstone and fine to coarse mudstone deposited by wind- and thermohaline-driven contour currents. Four ichnofabrics were recognized in three facies associations. The Palaeophycus heberti ichnofabric is dominant in facies association 1, forming highly bioturbated intervals. The Palaeophycus heberti, Nereites isp., and Phycosiphon incertum ichnofabrics are present in facies association 2, displaying highly, moderately and sparsely bioturbated intervals, respectively. This association is locally characterized by m-thick successions comprising an upward decrease and then increase in bioturbation index, which may have a similar origin to bigradational sequences. The Equilibrichnia-Fugichnia ichnofabric mostly occurs in facies association 3 and less commonly in 2, forming distinctive bioturbated intervals within sparsely bioturbated successions. Benthic activity was controlled by food distribution, oxygenation, hydrodynamic energy, and water turbidity. Food was delivered to the surface or in suspension by currents, promoting deposit- or suspension-feeding strategies in the infauna, respectively. Oxygen levels increased during contour current activity yet remained relatively low (upper dysoxic). Hydrodynamic energy controlled bioturbation intensity, resulting in lower degrees of bioturbation during higher energy events. Suspension-feeding strategies suggest that water turbidity was relatively low during current transport. The herein example increases our understanding of environmental controls of shallow-water contour currents, supporting the fact that high bioturbation levels are typical of contourite deposits and providing an example of muddy contourites showing high preservation of sedimentary structures due to oxygen deficiency in bottom waters.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"201 - 218"},"PeriodicalIF":1.6,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49356463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Lowe, A. Diefendorf, K. Schlanser, J. Super, C. K. West, D. Greenwood
Abstract: The early Eocene Okanagan Highland fossil sites of Washington (USA) and British Columbia (Canada) contain exquisitely preserved plant and insect fossils that showcase a critical time and place in the evolution of the Northern Hemisphere temperate deciduous biome. A comprehensive understanding of the dynamics of fossil deposition and preservation at these sites is not fully resolved but is critical for reliable reconstructions of these ancient forests. To expand on previous interpretations (e.g., deep, stratified, anoxic lake bottoms) and address uncertainties about the environment of deposition (e.g., distance to shore, influence of diatoms), we analyzed sediment samples from three Okanagan Highland fossil sites—McAbee, Falkland, and Driftwood Canyon—for organic biomarkers, their stable carbon isotopic compositions, and glycerol dialkyl glycerol tetraethers (GDGTs; at McAbee only). Terpenoids suggest relative trends in gymnosperm abundance between sites that agree with prior macrofossil evidence, though absolute values may overestimate local gymnosperm abundance. A combination of biomarker evidence indicates a predominantly autochthonous aquatic source (e.g., diatoms) for organic matter in shale and mudstone samples, even contributing to long chain n-alkanes and likely to branched GDGTs, which are often assumed to be terrestrially sourced. In combination with biomarker evidence for anoxia and stratification, fossiliferous shales are interpreted to have been deposited offshore in deep and mesotrophic lakes that were thermally stratified with an anoxic hypolimnion, away from in-flowing tributaries, while a coal horizon at Driftwood Canyon was deposited in a shallower, eutrophic, anoxic wetland. Anoxic conditions likely minimized some degradation-based biases and promoted high quality fossil preservation. Deposition of sediment and fossil remains offshore and away from inflowing tributaries suggest fossil plants were locally sourced but highlights the need for careful consideration of transport-induced biases.
{"title":"DYNAMICS OF DEPOSITION AND FOSSIL PRESERVATION AT THE EARLY EOCENE OKANAGAN HIGHLANDS OF BRITISH COLUMBIA, CANADA: INSIGHTS FROM ORGANIC GEOCHEMISTRY","authors":"A. Lowe, A. Diefendorf, K. Schlanser, J. Super, C. K. West, D. Greenwood","doi":"10.2110/palo.2021.007","DOIUrl":"https://doi.org/10.2110/palo.2021.007","url":null,"abstract":"Abstract: The early Eocene Okanagan Highland fossil sites of Washington (USA) and British Columbia (Canada) contain exquisitely preserved plant and insect fossils that showcase a critical time and place in the evolution of the Northern Hemisphere temperate deciduous biome. A comprehensive understanding of the dynamics of fossil deposition and preservation at these sites is not fully resolved but is critical for reliable reconstructions of these ancient forests. To expand on previous interpretations (e.g., deep, stratified, anoxic lake bottoms) and address uncertainties about the environment of deposition (e.g., distance to shore, influence of diatoms), we analyzed sediment samples from three Okanagan Highland fossil sites—McAbee, Falkland, and Driftwood Canyon—for organic biomarkers, their stable carbon isotopic compositions, and glycerol dialkyl glycerol tetraethers (GDGTs; at McAbee only). Terpenoids suggest relative trends in gymnosperm abundance between sites that agree with prior macrofossil evidence, though absolute values may overestimate local gymnosperm abundance. A combination of biomarker evidence indicates a predominantly autochthonous aquatic source (e.g., diatoms) for organic matter in shale and mudstone samples, even contributing to long chain n-alkanes and likely to branched GDGTs, which are often assumed to be terrestrially sourced. In combination with biomarker evidence for anoxia and stratification, fossiliferous shales are interpreted to have been deposited offshore in deep and mesotrophic lakes that were thermally stratified with an anoxic hypolimnion, away from in-flowing tributaries, while a coal horizon at Driftwood Canyon was deposited in a shallower, eutrophic, anoxic wetland. Anoxic conditions likely minimized some degradation-based biases and promoted high quality fossil preservation. Deposition of sediment and fossil remains offshore and away from inflowing tributaries suggest fossil plants were locally sourced but highlights the need for careful consideration of transport-induced biases.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"185 - 200"},"PeriodicalIF":1.6,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48461354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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