Uplands, lowlands, and climate: Taphonomic megabiases and the apparent rise of a xeromorphic, drought-tolerant flora during the Pennsylvanian-Permian transition

DiMichele, William A.; Bashforth, Arden R.; Falcon-Lang, Howard J.; Lucas, Spencer G.

doi:10.1016/j.palaeo.2020.109965

Cited by 42 publications

(11 citation statements)

References 205 publications

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“…It is important to note that the terrestrial fossil record primarily derives from lowland settings, especially lacustrine and riparian environments, where much sediment accumulates. This preservation bias is especially the case for the plant record, which is dominated by plants from wetlands, owing to the good preservation conditions in such settings 105 . Much less is known about plants from drier and upland habitats, which rarely fossilize, although evidence of upland vegetation loss during the PTME has been inferred from changing sedimentary facies in the Karoo basin and Russia 106 .…”

Section: Spore Tetradsmentioning

confidence: 99%

Environmental crises at the Permian–Triassic mass extinction

Corso

Song

Callegaro

et al. 2022

Nat Rev Earth Environ

104

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Many mass extinction events punctuated the history of life and changed evolutionary trajectories 1 . Most past biological crises are coeval with the emplacement of Large Igneous Provinces (LIPs) 2 , which trigger widespread environmental perturbations. The Permian-Triassic mass extinction (PTME; 252 million years ago (Ma)) was the most severe biological crisis of the Phanerozoic (FIg. 1). It almost completely eliminated Palaeozoic fauna and flora, setting the stage for the evolution of modern ecosystems. Across the Permian-Triassic boundary (PTB), 81-94% of marine species went extinct 3-5 . On land, 89% of tetrapod genera and 49% of tetrapod families disappeared 6 . Recovery began in the Early Triassic 7-9 , but became notable only in the Middle Triassic, 5 million years later [10][11][12] .Data from the fossil, sedimentary, and geochemical record of the PTME suggest that there were major environmental changes in marine and terrestrial settings [13][14][15] . The global crisis is coeval with the emplacement of the Siberian Traps Large Igneous Province (STLIP) [16][17][18] , that saw a relatively rapid (<1 Ma) eruption of 2-7 million km 3 of basalt [19][20][21][22] , together with volcanic emissions of CO 2 , SO 2 , halogens and metals that were capable of causing the global climate and environmental catastrophe.Knowledge of the detailed timing of events has improved remarkably in the 2010s, thanks to advances in high-precision radioisotope dating, and highresolution biostratigraphy and chemostratigraphy (especially C-isotope and Hg stratigraphy). Analysis of high-temporal-resolution PTB events allowed identification of distinct phases of STLIP eruptions 18,23 and separate pulses of extinction among marine animals 4,24,25 . Particularly interesting developments include the increasing evidence that the terrestrial crisis was very likely to have been underway several tens to hundreds of thousands of years before the marine extinction [26][27][28] , clearly indicating that the PTME was not a single, instantaneous catastrophic event. Although these findings expand our knowledge of STLIP volcanism, Mass extinctionglobal biological events of greatly elevated extinction rates. Large Igneous Province(LIPs). Rapidly emplaced (<1-5 Ma) volcanic provinces with areal extents >0.1 million km 2 and volumes >0.1 million km 3 . Radioisotope datingTechnique to determine the absolute age of rocks using radioactive decay.

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Section: Spore Tetradsmentioning

confidence: 99%

Environmental crises at the Permian–Triassic mass extinction

Corso

Song

Callegaro

et al. 2022

Nat Rev Earth Environ

104

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“…2017; DiMichele et al . 2020) the late Palaeozoic tectono‐climatic trends shaped and interacted with shifting proportions and the evolution of the major plant and animal groups (e.g. Kerp 1996; Balseiro 2016; Luthardt et al .…”

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confidence: 99%

Decoding the drivers of deep‐time wetland biodiversity: insights from an early Permian tropical lake ecosystem

et al. 2023

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Wetlands are important to continental evolution, providing both arenas and refugia for emerging and declining biotas. This significance and the high preservation potential make the resulting fossiliferous deposits essential for our understanding of past and future biodiversity. We reconstruct the trophic structure and age of the early Permian Manebach Lake ecosystem, Germany, a thriving wetland at a time when the tropical biosphere faced profound upheaval in the peaking Late Palaeozoic Icehouse. Nine excavations, high‐resolution spatiotemporal documentation of fossils and strata, and U–Pb radioisotopic dating of tuffs allow us to distinguish autogenic and allogenic factors shaping the limnic biocoenosis. The Manebach Lake was an exorheic, oxygen‐stratified, perennial water body on the 101–102 km2 scale, integrated into the catchment draining much of the European Variscides. Lake formation paralleled an Asselian regional wet climatic interval and benefited from rising base level due to post‐Variscan half‐graben tectonics. Stromatolite‐forming cyanobacteria, bivalves, several crustaceans, amblypterids and xenacanthid sharks formed a differentiated biocoenosis in the lake. Fossil stomach remains and teeth prove the rare presence of acanthodians, branchiosaurs and large amphibians. The results indicate woody‐debris‐bearing lake littorals devoid of semi‐aquatic and aquatic plants as places suitable for stromatolites to grow, underpin the model of declining freshwater‐shark diversity in most Permian Variscan basins, demonstrate fish/amphibian ratios in limnic assemblages to measure lake perenniality and reveal taphonomic biases in lake taphocoenoses. Our outcomes call for more knowledge about the diversity, ecology and fossilization pathways of past limnic biotas, particularly microorganisms and actinopterygian fishes, to reconstruct deep‐time continental ecosystems.

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“…Hence, fossil-plant assemblages in fully continental successions, such as the Bogda Mountains, represent small and very limited “windows” into vegetation at any specific point in time during which these Permian–Triassic landscapes existed (Gastaldo et al 2005). This contrasts with coastal megafloral records, particularly in the Mississippian (e.g., Gastaldo et al 2009), Pennsylvanian (e.g., Montañez et al 2016), and early Permian (e.g., DiMichele et al 2020), from which long-term biodiversity and ecological trends in stability, turnover, extirpation, and extinction can be discerned with greater confidence. But, the question remains about the actual potential to encounter megafloral assemblages in this stratigraphic record.…”

Section: Discussionmentioning

confidence: 66%

The Taphonomic Character, Occurrence, and Persistence of Upper Permian–lower Triassic Plant Assemblages in the Mid-Paleolatitudes, Bogda Mountains, Western China

Gastaldo

Wan

Yang

2023

Palaios

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The Bogda Mountains, Xianjiang Uygur Autonomous Region, western China, expose an uppermost Permian–Lower Triassic succession of fully continental strata deposited across three graben (half graben) structures in the mid-paleolatitudes of Pangea. A cyclostratigraphy scheme developed for the succession is subdivided into three low-order cycles (Wutonggou, Jiucaiyuan, Shaofanggou). Low-order cycles are partitioned into 1838 high-order cycles based on repetitive environmental changes, and their plant taphonomic character is assessed in > 4700 m of high-resolution, measured sections distributed across ∼ 100 km. Four taphonomic assemblages are represented by: permineralized wood (both autochthonous and allochthonous), megafloral adpressions (?parautochthonous and allochthonous) identifiable to systematic affinity, unidentifiable (allochthonous) phytoclasts concentrated or disseminated on bedding, and (autochthonous) rooting structures of various configurations (carbon films to rhizoconcretions). Their temporal and spatial occurrences vary across the study area and are dependent on the array of depositional environments exposed in any particular locality. Similar to paleobotanical results in other fully continental basins, megafloral elements are rarely encountered. Both wood (erect permineralized stumps and prostrate logs) and adpressions are found in < 2% of meandering river and limnic cycles, where sediment accumulated under semi-arid to humid conditions. The absence of such assemblages in river-and-lake deposits is more likely related to physical or geographical factors than it is to an absence of organic-matter contribution. With such a low frequency, no predictable pattern or trend to their occurrence can be determined. This is also true for any horizon in which rooting structures are preserved, although paleosols occur in all or parts of high-order cycles developed under arid to humid conditions. Physical rooting structures are encountered in only 23% of these and are not preserved equally across space and time. Allochthonous phytoclasts are the most common taphonomic assemblage, preserved in association with micaceous minerals on bedding in fine-grained lithofacies. The consistency of phytoclast assemblages throughout the succession is empirical evidence for the presence of riparian vegetation during a time when models propose the catastrophic demise of land plants, and does not support an interpretation of vegetational demise followed by long-term recovery across the crisis interval in this basin. These mesofossil and microfossil (palynological) assemblages offer the best opportunity to understand the effects of the crisis on the base of terrestrial ecosystems.

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Uplands, lowlands, and climate: Taphonomic megabiases and the apparent rise of a xeromorphic, drought-tolerant flora during the Pennsylvanian-Permian transition

Cited by 42 publications

References 205 publications

Environmental crises at the Permian–Triassic mass extinction

Environmental crises at the Permian–Triassic mass extinction

Decoding the drivers of deep‐time wetland biodiversity: insights from an early Permian tropical lake ecosystem

The Taphonomic Character, Occurrence, and Persistence of Upper Permian–lower Triassic Plant Assemblages in the Mid-Paleolatitudes, Bogda Mountains, Western China

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