Kunio Kaiho

• Doctor of Science
• Professor at Tohoku University

This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentar...

While it is widely accepted that early animals originated and primarily evolved during the Neoproterozoic to Cambrian period, there remains ongoing debate over how fluctuations in marine-atmospheric oxygen levels influenced their evolution and diversification. To investigate this, we analyzed pristane/phytane ratios—a redoxproxy based on organic ge...

The Early Triassic after the end-Permian mass extinction was a time of repeated environmental degradation, which delayed biotic recovery. Although repeated volcanic activity during the Early Triassic has been cited as the cause, the evidence for this hypothesis needs to be confirmed with convincing proxies. This study presents sedimentary molecular...

The exact drivers for the end-Permian mass extinction (EPME) remain controversial. Here we focus on a ~10,000 yr record from the marine type section at Meishan, China, preceding and covering the onset of the EPME. Analyses of polyaromatic hydrocarbons at sampling intervals representing 1.5–6.3 yr reveal recurrent pulses of wildfires in the terrestr...

An environmental–animal crisis is currently ongoing and is becoming increasingly severe due to human activity. However, the magnitude, timing, and processes related to this crisis are unclear. This paper clarifies the likely magnitude and timing of animal extinctions and changes in the contribution rates of select causes (global warming, pollution,...

A major bio-crisis in the Guadalupian−Lopingian transition (Capitanian−Wuchiapingian, middle−late Permian), possibly driven by the volatile eruption of the Emeishan large igneous province (LIP), was marked by the first-order collapse of global metazoan reefs and decline of fusulinid foraminifera, but with only minor impacts on other marine inverteb...

There have been five major mass extinctions and some minor mass extinctions of animals since early animal diversification 540–520 Myr ago. It is said that a sixth mass extinction is already underway. However, the future extinction magnitude has not been quantitatively estimated. Here, I show that the sixth major mass extinction (defined as > 60% sp...

The composition of past photosynthetic organisms provides information about the paleo-environment based on the habitat characteristics of photosynthetic organisms. Therefore, analysis of chlorophyll-derived materials from photosynthetic organisms in sedimentary rocks is important for understanding paleo-environmental changes. Fossilized chlorophyll...

The end-Permian mass extinction was the most catastrophic event for life in the Phanerozoic eon because it impacted numerous organisms, from micro-sized photosynthetic organisms to large (meter-long) animals and fundamentally altered marine and terrestrial ecosystems. C33 n-alkyl cyclohexane (C33-ACH), an angstrom-size molecular fossil of phytoplan...

Major mass extinctions in the Phanerozoic Eon occurred during abrupt global climate changes accompanied by environmental destruction driven by large volcanic eruptions and projectile impacts. Relationships between land temperature anomalies and terrestrial animal extinctions, as well as the difference in response between marine and terrestrial anim...

Major mass extinctions in the Phanerozoic Eon occurred during abrupt global climate changes accompanied by environmental destruction driven by large volcanic eruptions and projectile impacts. However, relationships between those physical conditions and the magnitude of animal extinctions have not been quantitatively evaluated. My analyses show that...

Emplacement of the Central Atlantic Magmatic Province (CAMP) is thought to have triggered global environmental changes and the end-Triassic mass extinction (ETE). However, the mechanisms linking volcanism and environmental change are unclear. Here we provide new insight into these linkages by measuring the abundance of both sedimentary five- to six...

The late Neoproterozoic (645–535 Ma) represents a key geological period, when a climate shift and revolutionary biological innovations occurred during the Precambrian–Cambrian transition. The Marinoan glaciation impacted the climate and chemical composition of the oceans, restraining the evolution of early life. To elucidate evolutionary processes...

The Permian−Triassic mass extinction was the most severe biotic crisis of the past 540 million years, eliminating 80–90% of species in the ocean and ~ 70% of land-based vertebrate families. Researchers have debated whether terrestrial vegetation collapse occurred before or after the marine extinction, or if they were synchronous. We analyzed the ra...

The Late Devonian biodiversity crisis, one of the big five Phanerozoic diversity depletions, is composed of a series of extinction events broadly coincident with the invasion of land by plants and vertebrates. These extinctions may have been triggered by volcanism, as sedimentary mercury enrichments are associated with the two main extinctions, the...

Eruption of the Siberian Traps large igneous province (LIP) is thought to have triggered the Permian-Triassic biological crisis, the largest of the Phanerozoic mass extinctions. Mercury concentration enrichments have been widely used as a proxy for volcanic inputs to sediments, especially for ancient LIP eruptions. However, detailed correlations of...

A terrestrial ecosystem collapse event accompanied by extensive soil erosion has been widely recorded in marine sedimentary rocks at the vicinity of the end-Permian mass extinction. However, the precise timing of this event and its impact on the marine extinction have not yet been ascertained. Here we present an organic geochemical study of non-mar...

Biotic extinction during the Guadalupian-Lopingian (G-L) transition is actively debated, with its timing, validity, and causality all questioned. Here, we show, based on detailed sedimentary, paleoecologic, and geochemical analyses of the Penglaitan section in South China, that this intra-Permian biotic crisis began with the demise of a metazoan re...

Sixty-six million years ago, an asteroid approximately 9 km in diameter hit the hydrocarbon- and sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot and sulfate aerosols and causing extreme global cooling...

The Kamura section, located in the Chichibu Belt of Kyushu Island in southern Japan, contains a succession of uppermost Permian to Upper Triassic shallow-marine atoll sediments from the mid-Panthalassic Ocean. In the present study, carbonate microfacies, conodont biostratigraphy, and carbonate carbon isotopes were analyzed, making it possible to co...

The Late Ordovician mass extinction (LOME), one of the five largest Phanerozoic biodiversity depletions, occurred in two pulses associated with the expansion and contraction of ice sheets on Gondwana during the Hirnantian Age. It is widely recognized that environmental disruptions associated with changing glacial conditions contributed to the extin...

Biphytanes, which are derived from glycerol dialkyl glycerol tetraether (GDGT) lipids, are biomarkers for the presence of Archaea in geological samples. They (especially cyclic structures) are rarely reported from sediments or oils that are older than the Triassic period, where their first record may be traced back to the Late Archean. There have b...

The Late Ordovician mass extinction (LOME) was one of the five largest Phanerozoic marine diversity depletions. The extinction event occurred in two pulses, associated with the expansion and contraction of ice sheets on Gondwana during the Hirnantian Stage. It is widely recognized that environmental changes associated with peak glacial conditions d...

The largest mass extinction of biota in the Earth’s history occurred during the Permian–Triassic transition and included two extinctions, one each at the latest Permian (first phase) and earliest Triassic (second phase). High seawater temperature in the surface water accompanied by euxinic deep-intermediate water, intrusion of the euxinic water to...

The mass extinction of life 66 million years ago at the Cretaceous/Paleogene boundary, marked by the extinctions of dinosaurs and shallow marine organisms, is important because it led to the macroevolution of mammals and appearance of humans. The current hypothesis for the extinction is that an asteroid impact in present-day Mexico formed condensed...

Investigations of calcareous nannoplankton assemblages including species richness and abundance data were performed across the K–Pg boundary interval at Agost (SE Spain), between − 100 cm and + 100 cm, below and, respectively, above the boundary, at a considerable high resolution averaging 2 cm. From a total of 98 species of the Upper Maastrichtian...

We investigated the distribution of lipids in Lower Triassic sedimentary rocks (252–247 myr) from South China, including a shallow water microbialite in the uppermost section of the outcrop. Archaeal derived hydrocarbons were the major constituents of the microbialite from the latest Early Triassic. Among these, we detected (i) abundant C40 acyclic...

Kaiho et al. (2013) showed that high values of organic molecule indices of combustion, soil erosion, and euxinia occurred at the Frasnian-Famennian transition at Sinsin, Belgium. Marynowski and Racki (2014) commented on the paper. Their issues mainly address (1) the low resolution of the data, (2) the reliability of the proxies, (3) weathering as a...

The Meishan section, South China is the Global Stratotype Section and Point (GSSP) for the Permian-Triassic boundary (PTB), and also is well known for the best record demonstrating the Permian-Triassic mass extinction (PTME) all over the world. This section has also been studied using multidisciplinary approaches to reveal the possible causes for t...

The greatest mass extinction on Earth occurred 252 million years ago during the latest Permian. Complete biotic recovery, characterized by a return to pre-extinction diversity levels, took an extraordinarily long time (ca. 5 x 106 yr), probably because harsh conditions developed repeatedly during the Early Triassic. Here, we show the recurrence of...

To improve international stratigraphic correlation of the Lower Guadalupian–Lower Lopingian (Permian), we examined the stratigraphies of conodonts and organic carbon isotopes from pelagic chert sequences in the Gujo-hachiman section, Gifu, southwest Japan. Age-diagnostic conodonts, such as Jinogondolella nankingensis and Jinogondolella shannoni wer...

Oceanic Anoxic Event 2 (OAE 2) during the Cenomanian-Turonian (C/T) transition caused stepwise marine extinctions. Using organic compounds, stable carbon and oxygen isotopes, and foraminifera from three depth-transect sections in northern Spain, this study revealed repeated anoxic/euxinic events coinciding with warming and stepwise extinctions of p...

On Cat Ba Island in northeastern Vietnam, the Devonian to Carboniferous (D–C) transition consists mainly of ramp carbonates intercalated with black shale beds (Beds 1 to 176) in the Pho Han Formation and is one of the few records of the D–C transition of the eastern Paleotethys. The three main facies of the sequence are Facies 1 (alternations of wh...

The Late Devonian mass extinction occurred in a stepwise manner and culminated close to the Frasnian–Famennian (F–F) boundary (372 million years ago). Organic-molecular indices from marine sedimentary rocks at the Sinsin section, Belgium, indicate that the sequence of combustion of land vegetation, soil erosion, and anoxia–euxinia occurred close to...

The Cenomanian–Turonian boundary interval of the Arobes section, northern Spain, represents the maximum depth of a relatively shallow succession. The investigated section extends within the Rotalipora cushmani and Whiteinella archaeocretacea planktonic foraminiferal zones, and from UC3 up to UC8 nannofloral zones, respectively. The Oceanic Anoxic E...

Isotopic studies combined with geochemical, lithological, mineralogical and palaeontological investigations have been widely used in reconstructing Cretaceous marine and continental environments. Furthermore stable and radiogenic isotope trends play an important role in the interpretation of the causes and consequences of biotic turnovers at strati...

Mesozoic accretionary complexes in Japan and New Zealand contain Panthalassic low latitude and southern mid-latitude deep-water sedimentary rock respectively. These sedimentary rocks record environmental changes in the pelagic Panthalassic Ocean during the transition associated with the severe Permian–Triassic mass extinction. This study presents s...

Land–plant productivity was greatly reduced after the end-Permian mass extinction, causing a pronounced “coal gap” worldwide during the Early Triassic. Newly obtained organic geochemistry data from the Chaohu area, south China, indicated an abrupt and profound terrestrial vegetation change over the middle part of the Early Triassic Smithian–Spathia...

Ether lipids such as non-isoprenoid mono and dialkyl glycerol ethers (MAGEs and DAGEs) and archaeol have been found in carbonate rocks and mud rocks deposited during the Early and Middle Triassic (250–240 Ma). The oldest previous discovery of ether lipids is from Cretaceous black shale deposited during the Albian (112 Ma). Paleoenvironmental recons...

The impact of an extraterrestrial body 65.5 Ma caused the so-called Cretaceous/Paleogene (K/Pg) event that resulted in a mass extinction and rapid changes in the surface environment on Earth. Here we report changes in land vegetation and oceanic redox across the K/Pg boundary at Caravaca, southeastern Spain, using biomarkers. The results reveal tha...

Detailed fluorescent microscopic observations and organic geochemical analyses for insoluble sedimentary organic matter (kerogens) are conducted on the end-Permian to earliest Triassic sediments in the Meishan section A of South China. The main objectives of the present study are to reconstruct variations of marine and terrestrial environments, and...

Changes in redox conditions during the Changhsingian to Griesbachian spanning the end-Permian mass extinction were recently reported based on analyses of organic molecules. We provide more precise organic-molecular data, that detail redox conditions spanning the end-Permian mass extinction at different palaeowater depths in the neritic Palaeotethys...

Detailed geochemical analyses (δ13Ccarb, δ13Corg, δ34Ssulfide, and abundance of sulfide, carbonate and organic carbon) were performed on samples from the Wangjiawan (Riverside) section, close to the GSSP (Global Stratotype Section and Point) for the Hirnantian stage of the Ordovician. New data show two increases in carbonate content coincident with...

[Huang et al. (2011)][1] have produced a valuable astro-chronological framework across the Permian-Triassic boundary in China and Austria. However, in doing so they define a mass extinction interval (MEI) and prolonged extinction lasting in all cases ∼700 k.y. The MEI in their study ranges from

This paper describes fourteen brachiopod species in eleven genera from the Late Permian Wuchiapingian Coal Series (Lungtan Formation) of South China. Of these, the shell bed fauna from the basal Lungtan Formation is interpreted to rep− resent the onset of the recovery of shelly faunas in the aftermath of the Guadalupian/Lopingian (G/L) mass extinct...

Oceanic anoxic event 2 (OAE2), which occurred during the Cenomanian-Turonian (C-T) transition and lasted 1 m.y., is characterized by a positive global carbon isotopic excursion and stepwise extinctions in marine biota. To examine temporal variations in the dissolved oxygen content of the water column, shallow-marine C-T sediments from northern Spai...

Guadalupian–Lopingian sedimentary rocks are widely distributed in accretionary complexes in Japan, but the Guadalupian–Lopingian boundary (G–LB) is not well documented from these pelagic sediments. To identify the G–LB and to better correlate an extinction event that occurred around the Guadalupian–Lopingian boundary, we examined the conodont biost...

The end-Permian mass extinction is associated with a global perturbation in the carbon isotopic composition of carbonates and organic matter, but such changes are not well documented from pelagic deep-sea sediments. One of the most continuous pelagic deep-sea Permian/Triassic boundary (PTB) sections, the Am-2 section, is exposed in the accretionary...

A 2–4% negative shift of d 13 C has been reported from many Permian/Triassic (P/Tr) boundary sections around the world. Our carbon isotopic measurements of bulk carbonate and organic matter from the Meishan section, South China show that a –3% shift of d 13 C spanned *30 ka over the end-Permian mass extinction. Carbon isotopic excursions (d 13 C ca...

Fossil data show that the recovery of life after the end-Permian mass extinction occurred in the Anisian (early Middle Triassic). The process by which oceanic environments recovered from anoxia after the end-Permian event is uncertain. To determine the timing of known recovery stages, the nature of oceanic redox conditions and the health of cyanoba...

The paper reports results of experiments to estimate the mortality of ocean bottom dwellers, ostracoda, against underwater shock wave exposures. This study is motivated to verify the possible survival of ocean bottom dwellers, foraminifera, from the devastating underwater shock waves induced mass extinction of marine creatures which took place at g...

Impact tests were held to clarify the relationship between the composition of ejecta and these of the projectile and the target plate under different impact kinetic energy and impact velocity. Two sets of impact experiments were held, one using high carbon chromium bearing steel (SUJ-2) projectile and Al2017-T4 plate (Fe/Al impact), and the other u...

The greatest mass extinction occurred at the end of the Permian. Most records of the mass extinction are not from pelagic sediments, but from shallow-marine and terrestrial sediments. Although several pelagic sections that span the end-Permian mass extinction have been found, these sections contain few index fossils and are often discontinuous beca...

We have detected a family of benzohopanes cyclised at C-20 and two families of diaromatic 8(14)-secohopanoids, in carbonates from the Late Permian Meishan (China) and Bulla (Italy) sections. Furthermore, we have identified a C 33 8(14)-secohopanoid possessing a fluorene moiety. The relative distribution of 8(14)-secohopanoids with a fluorene moiety...

The mass extinction at the K/P (Cretaceous–Paleogene) boundary was caused by an extraterrestrial impact and the following abrupt climate/environment change. In this study, numerical simulations of asteroid/comet impact on the oceanic crust of the earth are carried out by using the hydrocode AUTODYN-2D (ANSYS, Inc.). The objective of this work is to...

Palaeontological data from the Permian-Triassic Bulla section, northern Italy, demonstrate a rapid extinction at this site. This occurs after a negative carbonate carbon-isotope (δ13Ccarb) shift, consistent with two other northern Italian sites (Val Badia and Tesero). However, conclusion goes against recent reporting that the extinction occurs befo...

In order to elucidate early Aptian marine paleotemperature evolution across the period of enhanced organic carbon (Corg)-burial [Oceanic Anoxic Event (OAE) 1a], stable isotope analyses were performed on pelagic limestones at Deep Sea Drilling Project Site 463, central Pacific Ocean. The δ18O data exhibit a distinct anomaly by ~ − 2‰ spanning the OA...

The effects of sulfate aerosols produced as a result of an asteroid impact on the ultra-violet (UV) radiation are investigated by radiative transfer calculations. After an impact, a reduction in the solar incident radiation and ozone depletion are expected to occur, each of which, in turn, are counteract their on effects on the UV radiation. We est...

Detailed (cm-scale) %S, %TOC (total organic carbon), δ34Ssulfide, and pyrite morphological analysis of the Permian–Triassic boundary beds at the Bulla section, northern Italy, suggests that marine waters at this site saw the influx of two dysoxic–euxinic intervals that mark the end-Permian extinction event. This suggests reduced oxygen conditions,...

Correlation of carbonate-associated sulfate (CAS) δ34S-analysed Permian-Triassic (P-Tr) sections via conodont biostratigraphy and sequence stratigraphy shows distinct phases in the oceanic δ34Ssulfate evolution during the period ∼1 million years (m.y.) either side of the P-Tr boundary. A δ34Ssulfate rise in the Changhsingian, prior to the end-Permi...

Paleontological, sedimentary and geochemical data obtained from the Lower Triassic strata of the Meishan section, South China, suggest that onset of biotic recovery coincided with amelioration of paleoceanographic conditions and an increase in ocean productivity. The Griesbachian Meishanorhynchia association from Meishan indicates biotic recovery b...

Although it is well known that the Paleocene/Eocene thermal maximum (PETM) coincided with a major benthic foraminiferal extinction event, the detailed pattern of the faunal turnover has not yet been clarified. Our high-resolution benthic foraminiferal and carbon isotope analyses at the low latitude Pacific Ocean Shatsky Rise have revealed the follo...

In order to evaluate the possible influence of oceanic crust production on climatic changes during the past 100Myr variations in total oceanic crust for this period including production at mid-ocean ridges, oceanic plateaus, and back-arc basins were calculated using the most recent and accurate time-scales. The rates presented here differ from thos...

Although it is well known that the Paleocene/Eocene thermal maximum (PETM) coincided with a major benthic foraminiferal extinction event, the detailed pattern of the faunal turnover has not yet been clarified. Our high-resolution benthic foraminiferal and carbon isotope analyses at the low latitude Pacific Ocean Shatsky Rise have revealed the follo...

In this study, numerical simulations of asteroid/comet impact on the earth were carried out by using the hydrocode AUTODYN-2D (Century Dynamics Inc.). The ejected mass into the atmosphere originated from different sources was recorded at different altitudes as a function of time. It is claimed that the mass extinction at the Permian–Triassic (P/T)...

A hypothesis of light sulfur injection to the ocean-atmosphere system at the end of the Permian was presented by Kaiho et al. [Kaiho, K., Kajiwara, Y.,Nakano, T., Miura, Y., Kawahata, H., Tazaki, K., Ueshima, M., Chen, Z.Q., Shi, G.R., 2001. End-Permian catastrophe by a bolide impact: evidence of a gigantic release of sulfur from the mantle. Geolog...

The Permian/Triassic (P/Tr) boundary beds of the Meishan section, South China, have been re-studied in detail based on complete samples across the P/Tr transition. Under the microscope, the end-Permian mass extinction horizon is calibrated to a 12-mm stratal interval, the top being 19 mm below the top of Bed 24e of the Changhsing Formation. This ab...

Paleocene–Eocene warming and changes in oceanic hydrography should have significantly impacted the ecology of marine microorganisms, both at the surface and on the seafloor. We analyzed several key characteristics of foraminifera from two Shatsky Rise (ODP Leg 198) cores spanning the P/E boundary including the maximum test diameters of the largest...

Eight brachiopod species in seven genera are described from the Permian–Triassic boundary beds of South China and northern Italy. The brachiopods from northern Italy are described for the first time and include two new species: Orbicoeliadolomitensis Chen and Spirigerella? teseroi Chen. The Permian affinity of these brachiopods and their stratigrap...

Brachiopod faunas in Lower Triassic deposits from Spitzbergen, Primorye of Russia, Japan, Mangyslak of Kazakhstan, Alpine Europe, the Caucasus, the Middle East, the Himalaya, South China, New Zealand, and western USA are taxonomically and stratigraphically reviewed. They comprise survivors of the end-Permian extinction and taxa originating in the E...

The mass extinction at the Cretaceous–Tertiary (K/T) boundary ca. 65 million years ago caused a major change in the nature and abundance of global life in Earth history. We present the first vertical high-resolution records of molecular distributions of n-fatty acids across the K/T boundary at Caravaca (Spain). The results reveal that the first bas...

Detailed qualitative and quantitative studies of the calcareous nannofloral assemblages were carried out on 65 cm across the K/T boundary interval of the Caravaca section. Preservation of nannofloral assemblages is moderate to good. Reworking was identified in the lowermost Danian, but did not essentially influence the rest of the section studied....

Global reviews reveal that 102 brachiopod species (including 40 indeterminate species) belonging to 43 genera within 27 families survived the end-Permian mass extinction in South China, the Himalayan regions (southern Tibet, Nepal, Salt Range and Kashmir), southern Alps (Italy), Arctic Canada, western USA and Western Australia. Of these, the surviv...

Palaeozoic life was severely affected in a pair of mass extinction events at the beginning (earliest Lopingian, 260 million years ago) and the end (251 million years ago) of the Late Permian. However, the biological and geochemical record of the earliest Lopingian crisis remains poorly constrained. We present analyses of strata in South China showi...

A new genus of ophiuroid, Huangzhishania, is created based on new material from the Permian/Triassic boundary beds at the Huangzhishan section, South China. The age of the new genus is constrained as earliest Griesbachian by means of faunal correlation of the associated bivalves and stratigraphical correlation with the Mixed Fauna Beds of the neigh...

A three-fold expansion of the Antarctic ice sheet at 13.60, 12.82, and 11.60 Ma has been inferred from δ18O maxima analyzed in planktonic and benthic foraminiferal tests, although accompanying changes in sea surface temperature have not been detailed. We present estimated changes in middle Miocene surface-water temperatures based on analysis of δ18...

A new genus, Meishanorhynchia, is proposed based on new material from the Lower Triassic of the Meishan section, South China. It is of a late Griesbachian age based on both associated biozones (ammonoids and bivalves) and radiometric dates of the intercalated volcanic ash beds. Comparison with both Palaeozoic and Mesozoic–Cenozoic-related genera su...

A three-fold expansion of the Antarctic ice sheet at 13.60, 12.82, and 11.60 Ma has been inferred from delta18O maxima analyzed in planktonic and benthic foraminiferal tests, although accompanying changes in sea surface temperature have not been detailed. We present estimated changes in middle Miocene surface-water temperatures based on analysis of...