Wildfires and deforestation during the Permian–Triassic transition in the southern Junggar Basin, Northwest China

Cai, Yao-feng; Zhang, Hua; Cao, Changqun; Zheng, Qi; Jin, Chuan-Fang; Shen, Shu-zhong

doi:10.1016/j.earscirev.2021.103670

Cited by 20 publications

(13 citation statements)

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“…In the case of rift lakes, the redistribution of sediments by turbidity currents (Zhang and Scholz 2015) results in similar accumulations on laminated bedding. Although systematic information can be obtained from these mesofossil assemblages, such investigations, to date, have centered on bedding whereupon either cuticular remains (e.g., Cai et al 2019) or charcoal occurs (e.g., Cai et al 2021). Second, similar pore-water geochemistries existed in both depositional environments at various points in time, promoting the decay (carbon films) or preservation (individual fragments) of phytoclast assemblages.…”

Section: Discussionmentioning

confidence: 99%

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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Section: Discussionmentioning

confidence: 99%

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 abundance of zircon suggests the possibility of local volcanism around the Permian–Triassic boundary. At this level in the Tianshan, the abundance of Hg suggests local volcanism (Cai et al, 2021). In the distant South China Block, volcanic ash gives a peak age of 253 Ma (Zhou et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Late Permian‐Early Triassic intracontinental tectonic inversion in the Junggar Basin, NW China: New insights from detrital zircon geochronology and seismic reflection data

Tang,

Pan,

Pe‐Piper

et al. 2023

Basin Research

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The Junggar Basin is located on the southwestern margin of the Central Asian Orogenic Belt (CAOB). Whether the Late Permian‐Early Triassic tectonic inversion there recorded the final closure of the North Tianshan Ocean or post‐accretionary intracontinental deformation remains controversial. Linking the structural style and provenance analysis of the western and northern margins of the Junggar Basin can provide a better understanding of this tectonic event and its geodynamic mechanisms. Seismic reflection profiles show that Early Permian syn‐rift half‐grabens were followed by the Middle Permian thermal sag, which is characterized by regional onlap and the migration of the depocentre to the centre of the basin. Together with the published isopach and palaeogeography maps in the western margin of the Junggar Basin, the seismic profiles demonstrate that the reactivation of the Ke‐Bai and Wu‐Xia dextral transpressive fault zones between the West Junggar terrane and the Mahu sag controlled the tilting and deformation of pre‐Permian strata and the distribution of Late Permian‐Early Triassic fan deltas. The reported igneous and sedimentological evidence indicates that the southern margin of the Junggar Basin was a rift basin controlled by transtensional strike‐slip faults in the Early Permian, and also was followed by a Middle Permian thermal sag. Quantitative provenance analysis using detrital zircon geochronology and the DZmix program shows that the West Junggar terrane and Tianshan orogenic belts experienced varied uplift, indicative of a transition from the Middle Permian thermal sag peneplanation to the Late Permian‐Early Triassic tectonic inversion involving reactivation of Early Permian normal faults. This intracontinental deformation event in the Junggar Basin was taken up by block counterclockwise rotation during the final amalgamation of the Pangea, which may be the long‐range effect of the final closure of Paleo‐Asia Ocean in the eastern part of the CAOB.

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“…RaNgE#?!1-26#?! PERMIAN-TRIASSIC WILDFIRES OF EASTERN GONDWANA P A L A I O S and China (Chu et al 2020;Cai et al 2021a) both reveal high inertinite/ charcoal abundances up to several meters above the uppermost Permian coals, representing a substantial duration after the primary phase of ecosystem collapse. Rather than indicating a direct cause of extinctions, high abundances of charcoal in the aftermath of the EPE may partly derive from the combustion of peat biomass that had died from other causes.…”

Section: Wildfires Of the End-permian Ecosystem Collapse: A Cause Amentioning

confidence: 99%

“…Several Siberian Traps-related extinction drivers have been advanced for continental ecological collapse during the EPE, including severe temperature increase (Bernardi et al 2018;, freshwater microbial blooms (Mays et al 2021a), acid rain (Black et al 2014;Sephton et al 2015), heavy metal toxicity (see review by Grasby et al 2020) and ozone depletion leading to enhanced UV-B radiation (Visscher et al 2004;Beerling et al 2007;Black et al 2014;Benca et al 2018). Wildfire, the combustion of land vegetation, has also been advanced as a potential EPE extinction driver on land (Feng et al 2020b;Cai et al 2021b), supported by an increase in fossil charcoal (Shen et al 2011b;Zhang et al 2016;Cai et al 2021aCai et al , 2021b, soot (Shen et al 2011a), and polycyclic aromatic hydrocarbons (PAHs; Grice et al 2007;Nabbefeld et al 2010;Shen et al 2011b;Zhou et al 2021; see review by Baker 2022). However, wildfires were frequent and widespread throughout the late Permian (Lopingian Epoch; 259.51-251.9 Ma), the interval leading up to the EPE, without any accompanying major biodiversity loss or discernible ecosystem disruption.…”

Section: Introductionmentioning

confidence: 99%

End-Permian Burnout: The Role of Permian–triassic Wildfires in Extinction, Carbon Cycling, and Environmental Change in Eastern Gondwana

Mays

McLoughlin

2022

Palaios

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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.

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Wildfires and deforestation during the Permian–Triassic transition in the southern Junggar Basin, Northwest China

Cited by 20 publications

References 92 publications

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

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

Late Permian‐Early Triassic intracontinental tectonic inversion in the Junggar Basin, NW China: New insights from detrital zircon geochronology and seismic reflection data

End-Permian Burnout: The Role of Permian–triassic Wildfires in Extinction, Carbon Cycling, and Environmental Change in Eastern Gondwana

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