Permian-Triassic Boundary Event Research Articles

Two types of hyperthermal events in the Mesozoic-Cenozoic: Environmental impacts, biotic effects, and driving mechanisms

A deeper understanding of hyperthermal events in the Earth’s history can provide an important scientific basis for understanding and coping with global warming in the Anthropocene. Two types of hyperthermal events are classified based on the characteristics of the carbon isotope excursion (CIE) of the five representative hyperthermal events in the Mesozoic and Cenozoic. The first type is overall characterized by negative CIEs (NCHE) and represented by the Permian-Triassic boundary event (PTB, ~252 Ma), the early Toarcian oceanic anoxic event (TOAE, ~183 Ma), and the Paleocene-Eocene Thermal Maximum event (PETM, ~56 Ma). The second type is overall characterized by positive CIEs (PCHE) and represented by the early Aptian oceanic anoxic event (OAE1a, ~120 Ma) and the latest Cenomanian oceanic anoxic event (OAE2, ~94 Ma). Hyperthermal events of negative CIEs (NCHE), lead to dramatic changes in temperature, sedimentation, and biodiversity. These events caused frequent occurrence of terrestrial wildfires, extreme droughts, acid rain, destruction of ozone layer, metal poisoning (such as mercury), changes in terrestrial water system, and carbonate platform demise, ocean acidification, ocean anoxia in marine settings, and various degree extinction of terrestrial and marine life, especially in shallow marine. In contrast, hyperthermal events of positive CIEs (PCHE), result in rapid warming of seawater and widespread oceanic anoxia, large-scale burial of organic matter and associated black shale deposition, which exerted more significant impacts on deep-water marine life, but little impacts on shallow sea and terrestrial life. While PCHEs were triggered by volcanism associated with LIPs in deep-sea environment, the released heat and nutrient were buffered by seawater due to their eruption in the deep sea, thus exerted more significant impacts on deep-marine biota than on shallow marine and terrestrial biota. This work enriches the study of hyperthermal events in geological history, not only for the understanding of hyperthermal events themselves, large igneous provinces, marine and terrestrial environment changes, mass extinctions, but also for providing a new method to identify the types of hyperthermal events and the inference of their driving mechanism based on the characteristics of carbon isotopic excursions and geological records.

First report on swimming trace fossils of fish from the Upper Permian and Lower Triassic of the Dolomites (Italy)

In the Upper Permian continental to marginal-marine succession of the Southern Alps (Dolomites, north Italy), the ichnological record consists of diverse vertebrate footprints and non-diverse invertebrate trace fossils, mainly occurring in the “Bletterbach ichnoassociation” of the Val Gardena Sandstone Formation. After the Permian-Triassic Boundary event, vertebrate ichnoassociations are scarce until the Middle Triassic (Anisian), whereas the uppermost Permian–Lower Triassic Werfen Formation preserves a rich invertebrate trace-fossil record. To date, fish body and trace fossils ( Undichna ) are very rare in the pre- and post-extinction deposits of the Dolomites; only Undichna gosiutensis Gibert, 2001 was identified in the “Voltago Conglomerate” (Middle Anisian), whereas some unidentified fossil fish casts were found in the Permian Val Gardena Sandstone and some fish remains in the overlying Werfen Formation. Recently, for the first time, fish trails have been discovered in the Val Gardena Sandstone (Lopingian) and in the Werfen Formation (Campil member, Early Triassic, Smithian). Val Gardena Sandstone yielded Undichna cf. quina Trewin, 2000 and U. bina Anderson, 1976 and these represent the oldest fish trails found in the Southern Alps so far. Conversely, the specimens found in the Werfen Formation can be assigned to Undichna cf. britannica Higgs, 1988. They represent the oldest Mesozoic record of fish trace fossils in northern Italy and one of the few records of Undichna from marine environments. These trace fossils are consistent with the fossil association found in the two formations and reflect fish swimming activity in different environments: in very shallow, calm, brackish distal-floodplain to marginal-marine environments in the Late Permian, in association with abundant and diverse tetrapod tracks, and non-diverse invertebrate trace fossils, and in inter- to subtidal calm, shallow, marine environments in the Early Triassic, together with abundant, but not diverse invertebrate trace fossils.

Origins of microspherules from the Permian–Triassic boundary event layers in South China

Volcanism and impact scenarios are two of the most plausible ways of interpreting the causes of the largest biological mass extinction at the end-Permian. Microspherules have previously been widely reported from tens of different Permian–Triassic boundary (PTB) sections in South China and some other regions. These microspherules have been interpreted as either the product of volcanic eruptions or an impact event. In order to test these scenarios, we collected 60 samples from 12 intensively-studied PTB sections in South China. In addition, four soil samples close to these PTB layers were also collected for comparison. Our investigation indicates that abundant microspherules with mosaic or dot shape crystals on rounded surface are present in the surface samples in the PTB layers at Meishan, Meili, and Shatian sections and most soil background samples in South China. Those microspherules consist of four different types based on their main chemical composition, surface features, and internal structure including iron, magnetite–silicate, glassy, pyrite microspherules and framboids. In contrast, microspherules have not been found in a few sections in remote areas such as the Selong Xishan section in Tibet and the Dalongkou section in Xinjiang, Northwest China, in the deeply-excavated samples at the Shangsi section and the hard tuff layers around the PTB at the Xiaochehe Section in Guiyang. Microspherules decrease in abundance with depth in PTB clay beds. All these microspherules except the pyrite microspherules and framboids are found in both the PTB layers and the nearby soil background samples. The iron microspherules are pure iron oxides such as magnetite, hematite or maghemite and contain low concentrations of nickel and chromium, and lack an Ni–Fe core and general extraterrestrial mineral wüstite. All these external and chemical characteristics suggest that most of iron microspherules previously reported from PTB sections in South China are modern industrial fly ashes. A low ratio of Fe3 +/FeTotal in crystals of magnetite–silicate microspherules and high ZnO contents can identify them as industrial contaminants. The pyrite microspherules and framboidal pyrite found from bed 24e and bed 26 at the Meishan sections are of depositional or/and diagenetic origins, and only the rounded quartz and the fragments containing extremely high SiO2 and TiO2 are possibly of volcanic origin.

The terrestrial Permian–Triassic boundary event bed is a nonevent: COMMENT

We welcome the fact that [Gastaldo et al. (2009)][1] have been continuing research in the Karoo of South Africa; those of us who have worked there know how important new research in this area is if we are to ever understand the causes of the Permian–Triassic mass extinction on land. However, here

The terrestrial Permian–Triassic boundary event is a nonevent: REPLY

We are pleased to reply to [Ward et al. (2012)][1] about the stratigraphic record of the Karoo Basin where the terrestrial ecosystem response to the End-Permian extinction is recorded. The present extinction model envisions a marine and terrestrial response coupling. The Permian–Triassic boundary

Biodiversity evolution through the Permian-Triassic Boundary event: ostracods from the Bükk Mountains, Hungary

One of the most complete Permian-Triassic boundary sections located in the Bukk Mountains (Hungary) was sampled for ostracod study. Seventy−six species are recognized, belonging to twenty genera. Fifteen new species are described and figured: Acratia? jeanvannieri Forel sp. nov., Acratia nagyvisnyoensis Forel sp. nov., Bairdia anisongae Forel sp. nov., Bairdia davehornei Forel sp. nov., Callicythere? balvanyseptentrioensis Forel sp. nov., Cytherellina? magyarorsza− gensis Forel sp. nov., Eumiraculum desmaresae Forel sp. nov., Hollinella fengqinglaii Crasquin sp. nov., Hungarella gerennavarensis Crasquin sp. nov., Langdaia bullabalvanyensis Crasquin sp. nov., Liuzhinia venninae Forel sp. nov., Liuzhinia bankutensis Forel sp. nov., Microcheilinella egerensis Forel sp. nov., Reviya praecurukensis Forel sp. nov., Shemonaella? olempskaella Forel sp. nov. One species is renamed: Bairdia baudini Crasquin nom. nov. Comparison of the Balvany North section with the Meishan section (Zhejiang Province, South China), Global Boundary Stratotype Sec− tion and Point (GSSP) of the Permian-Triassic Boundary (PTB), reveals discrepancies linked to the environmental set− ting and particularly to bathymetry. The stratigraphical distribution of all the species is given and diversity variations are discussed. The Balvany North section exhibits the lowest extinction rate of all PTB sections studied for ostracods analysis associated with a high level of endemism.

Multiple climatic changes around the Permian-Triassic boundary event revealed by an expanded palynological record from mid-Norway

Here, we present the palynological record from two shallow core holes (6611/09-U-01 and -02) from the Trondelag Platform offshore mid-Norway consisting of 750 m of Upper Permian and Lower Triassic sediments. The relatively homogeneous assemblages recovered from the Upper Permian deposits are dominated by gymnosperm pollen, mainly pteridosperms. At the base of the Griesbachian, numerous spore species appear in the record, leading to an increased diversity. The change at this boundary is also marked by the massive reduction of one group of pteridosperm pollen ( Vittatina ). Together with other typical Permian elements (e.g., Lueckisporites virkkiae ), this group is rare but consistently present in the lower part of the Griesbachian, and it gradually disappears in its upper part. The distribution of other groups such as taeniate and non-taeniate bisaccate gymnosperm pollen (pteridosperms and conifers) shows no significant change across the boundary, whereas spores and other gymnosperm pollen increase in diversity and abundance. These changes coincide with the formational change between the Schuchert Dal Formation (Upper Permian) and the Wordie Creek Formation (Griesbachian) equivalents. Late Permian and Griesbachian palynomorph assemblages display different patterns. The former show a homogeneous composition of low diversity, whereas the latter reflect diverse and variably composed floras. The data suggest that the arid phase of the Late Permian was followed by a humid phase at the base of the Griesbachian. In the Griesbachian section, a succession of six distinct palynological assemblages (phase II–VII) can be inferred. Comparable changes have been described from East Greenland. The variations in the palynological record are interpreted to reflect changing ecological conditions (e.g., changing humidity). Comparable variations in the distribution of δ 13 C isotope values reported from various sections from Greenland and China, showing stable values during the Late Permian and highly variable values during the Griesbachian, suggest common causes for the observed fluctuations. Multiphase volcanic activity of the Siberian traps seems to be the most likely candidate to have caused the variations in the δ 13 C isotope as well as in the palynological record. In contrast to the common claim that marine and terrestrial biota both suffered a mass extinction related to the Permian-Triassic boundary event, the studied material from the Norwegian midlatitudinal sites shows no evidence for destruction of plant ecosystems. The presence of diverse microfloras of Griesbachian age supports the idea that the climate in this area allowed most plants to survive the Permian-Triassic boundary event.

Biogeochemical evidence for euxinic oceans and ecological disturbance presaging the end-Permian mass extinction event

The Permian–Triassic Boundary event at 252.2 Ma marks the largest extinction of marine fauna in the Phanerozoic and there is a wide consensus that the extinction coincided with an intense oceanic anoxic event. The stratotype of the Changhsingian Stage, precisely constrained by the PTB Global Stratotype Section and Point (GSSP) and the GSSP for the Wuchiapingian–Changhsingian Boundary, both at Meishan in southern China, is well-documented in respect to geochronology and the pattern of extinction. Here we report secular trends in bulk isotopic parameters and lipid biomarkers in a core spanning 214 m of stratigraphic section across the PTB and through the entire Changhsingian interval. Our analysis of these data, viewed in the context of relative sea level change and strontium isotopes, reveals distinct shifts in paleoenvironmental conditions and profound changes in plankton ecology well before and following the biological extinction event. Specifically, patterns of steroids and triterpenoids indicate a marine plankton community that was heavily dominated by bacteria during the late Wuchiapingian, middle Changhsingian and early Griesbachian stages. Secular trends in aromatic hydrocarbons diagnostic for anoxygenic green sulphur bacteria (Chlorobiaceae) identify periods when euxinic conditions extended into the photic zone during the entire Changhsingian stage. Here also, the δ 15N of organic nitrogen progressively shifted from positive values around + 2 or + 3‰ to − 1‰ coincident with a sharp negative excursion in δ 13C org and slightly postdating the sharp minimum in δ 13C values of inorganic carbon that occurs at the top of Bed 24. These results, together the published chronology indicate that conditions unfavourable for aerobiosis existed in the marine photic zone at Meishan for 1.5 million years prior to the main phase of the biological extinction. The induction of marine euxinic conditions, worldwide, at the end of the Permian was likely a consequence of the aggregation of Pangea and the uplift, weathering and transport of nutrients to the ocean well in advance of the PTB. The protracted and widespread nature of the ensuing oceanic anoxic event suggests a causal association with the mass extinction.

Facies changes and diagenetic processes across the Permian–Triassic boundary event horizon, Great Bank of Guizhou, South China: a controversy of erosion and dissolution

AbstractThe Permian–Triassic boundary interval in shallow shelf seas of South China shows Upper Permian limestones overlain by lowermost Triassic microbialites. Global sea‐level rose across the Permian–Triassic boundary, but an irregular top‐Permian erosion surface across a 10 km north–south transect of the Great Bank of Guizhou contains evidence of sea‐level fluctuation. The surface represents the ‘event horizon’ of mass extinction, below the biostratigraphic Permian–Triassic boundary defined by first appearance datum of conodont Hindeodus parvus. An Upper Permian foraminiferal grainstone beneath this surface contains geopetal sediments, etched grains, and pendent and meniscus cements interpreted here as vadose. However, these latter diagenetic processes occurred before the event horizon and were followed by erosion of the final Permian surface. This erosion cuts previous fabrics but lacks evidence of weathering or bioerosion. A few centimetres below is an earlier grainstone that was also eroded but lacks proof of sub‐aerial processes. Samples therefore reveal one, or possibly two, small‐scale relative sea‐level changes before the Triassic transgression in this area, and these may relate to local tectonics. The final Permian surface is subject to at least four interpretations: (i) sub‐aerial physical erosion and dissolution by carbon dioxide‐enriched fresh water or carbon dioxide‐enriched mixed water, prior to Triassic transgression; (ii) sub‐aerial physical erosion overprinted by dissolution related to carbon dioxide‐enriched sea water in the Early Triassic transgression; (iii) submarine dissolution affected by acidified sea water due to rapid increase in volcanically‐derived carbon dioxide and oxidized methane released from marine clathrates; (iv) submarine dissolution due to acid anoxic waters rising across the continental shelf, unrelated to atmospheric carbon dioxide or oxidized methane. Field and petrographic evidence suggests that (i) is the simplest option; and it is possible that (ii) and (iii) occurred, but none are proved. Option (iv) is unlikely given the evidence and modelling of supersaturation of upwelled waters with respect to bicarbonate.

The terrestrial Permian-Triassic boundary event bed is a nonevent

Research Article| March 01, 2009 The terrestrial Permian-Triassic boundary event bed is a nonevent Robert A. Gastaldo; Robert A. Gastaldo 11Department of Geology, Colby College, Waterville, Maine 04901, USA Search for other works by this author on: GSW Google Scholar Johann Neveling; Johann Neveling 22Council for Geosciences, Private Bag x112, Silverton, Pretoria 0001, South Africa Search for other works by this author on: GSW Google Scholar C. Kittinger Clark; C. Kittinger Clark 11Department of Geology, Colby College, Waterville, Maine 04901, USA Search for other works by this author on: GSW Google Scholar Sophia S. Newbury Sophia S. Newbury 11Department of Geology, Colby College, Waterville, Maine 04901, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Robert A. Gastaldo 11Department of Geology, Colby College, Waterville, Maine 04901, USA Johann Neveling 22Council for Geosciences, Private Bag x112, Silverton, Pretoria 0001, South Africa C. Kittinger Clark 11Department of Geology, Colby College, Waterville, Maine 04901, USA Sophia S. Newbury 11Department of Geology, Colby College, Waterville, Maine 04901, USA Publisher: Geological Society of America Received: 13 Jun 2008 Revision Received: 15 Oct 2008 Accepted: 16 Oct 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2009 Geological Society of America Geology (2009) 37 (3): 199–202. https://doi.org/10.1130/G25255A.1 Article history Received: 13 Jun 2008 Revision Received: 15 Oct 2008 Accepted: 16 Oct 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Robert A. Gastaldo, Johann Neveling, C. Kittinger Clark, Sophia S. Newbury; The terrestrial Permian-Triassic boundary event bed is a nonevent. Geology 2009;; 37 (3): 199–202. doi: https://doi.org/10.1130/G25255A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A unique isochronous interval in the Karoo Basin, South Africa, previously has been interpreted to postdate vertebrate extinction at the Permian-Triassic boundary in the Bethulie area, Lootsberg Pass, and elsewhere. It is demonstrated that the laminated beds, or laminites, in the Bethulie region are stratigraphically indistinct. The heterolithic interval exposed on the Heldenmoed farm is ~8 m below the Bethel farm section, <1 km away. At Lootsberg Pass, the laminated interval is below the Permian-Triassic boundary as defined by vertebrate biostratigraphy, rather than overlying it. Hence, this interval, critical to models of end-Permian mass extinction, is neither isochronous across the basin nor unique. Rather, the lithofacies represents avulsion channel-fill deposits within aggradational landscapes. South African models for the response of terrestrial ecosystems to the perturbation in the marine realm require critical reevaluation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Permian-Triassic boundary event and eruption of the Siberian flood basalts: An inter-laboratory U–Pb dating study

The Permian-Triassic boundary event and eruption of the Siberian flood basalts: An inter-laboratory U–Pb dating study

Stable carbon isotope stratigraphy across the Permian–Triassic boundary in shallow marine carbonate platforms, Nanpanjiang Basin, south China

A distinct negative δ 13C excursion is documented in two Permian–Triassic sections (Heping and Taiping) in shallow marine carbonate platform deposits in the Nanpanjiang Basin, south China. These sections span from the Changhsingian to the Dienerian and are characterized by a distinct marine boundary facies change from massive, skeletal lime packstone in the Changhsingian to distinctive calcimicrobial framestone in the Griesbachian Hindeodus parvus Zone. The δ 13C org and δ 13C carb excursions occur directly after the onset of the calcimicrobial framestone (herein termed the ‘Permian–Triassic boundary event’) and before the first occurrence of H. parvus. The isotope shifts are associated with a sharp drop in species abundance and diversity and coincide with a decrease in total organic carbon (TOC) content. The shift towards depleted values in δ 13C org and δ 13C carb at the Permian–Triassic boundary event, together with low TOC contents, persists throughout the Griesbachian H. parvus Zone. These data document a corresponding negative shift of δ 13C org and δ 13C carb, values and low TOC contents with the onset of growth of calcified microbial framestones (a postextinction ‘disaster facies’) immediately below the base of the Griesbachian H. parvus Zone. Based on paleontological evidence, the first occurrence of the ‘disaster facies’ follows the extinction event, which implies that the 13C-depleted values above this facies postdate the event. This suggests that two separate events had to account for the initiation of the extinction and the δ 13C excursion. However, the consequences that led to the negative isotopic shift might be linked to the intriguing recovery lag of Early Triassic ecosystems. Based on data from PTB sections worldwide of a greater δ 13C offset in high compared with low latitudes, we propose that methane eruptions from thermal destabilization of high-latitude clathrate deposits may have led to the negative δ 13C shift and may have caused long-term adverse ecological conditions.

The Permian-Triassic boundary event: a geochemical study of three Chinese sections

Trace elements were determined in two well-documented Chinese Permian-Triassic (P/Tr) boundary sections (Meishan and Shangsi) and in a new section (Liangfenya). Iridium concentrations range from 3 to 87 pg/g, at or below levels in common sedimentary rocks. The results contrast with previous reports of high Ir concentration in the Meishan and Shangsi sections and offer no support to suggestions of a major meteoroid impact at the end of the Permian. A notable feature in each of these widely separated P/Tr sections (500–1500 km) is the existence of 2–5 light-colored clay layers at and near the boundary. These clay layers are strongly enriched in Cs, Zr, Hf, Ta, and Th and depleted in Cr, Co, and Ir, indicating that they are altered ash, apparently from the same massive silicic volcanic eruptions. We estimate the magnitude of these eruptions to be a few thousand km 3 of magma, a volume comparable to the great Toba eruption.