Robert J Newton

University of Leeds · School of Earth and Environment

Warming-induced marine anoxia has been hypothesized as an environmental stressor for the end-Triassic mass extinction (ETME), but links between the spread of marine anoxia and the two phases of extinction are poorly constrained. Here, we report iron speciation and trace metal data from the Bristol Channel Basin and Larne Basin of the NW European ep...

The end-Triassic mass extinction (ETME) was associated with intensified deep-water anoxia in epicontinental seas and mid-depth waters, yet the absolute oxygenation state in the shallow ocean is uncharacterized. Here we report carbonate-associated iodine data from the peritidal Mount Sparagio section (Southern Italy) that documents the ETME (~ 200 M...

Past major biological turnovers are coeval to large injections of CO2 into the atmosphere–ocean system that are often linked to the emplacement of Large Igneous Provinces. The impact of these CO2 pulses on ecosystems is however different at different times, and this difference is contingent on the initial boundary conditions. Here, we show how dela...

The climatic and environmental impact of exclusively volcanic CO2 emissions is assessed during the main effusive phase of the Central Atlantic Magmatic Province (CAMP), which is synchronous with the end-Triassic mass extinction. CAMP volcanism occurred in brief and intense eruptive pulses each producing extensive basaltic lava flows. Here, CAMP vol...

The Early Jurassic is an important interval characterized by several global carbon-isotope (δ13C) perturbations. Although the δ13C records are becoming better documented during this time interval, we have a relatively poor understanding of the associated long-term environmental and climatic changes. In order to decipher these events, we here presen...

The Ediacaran Period was characterised by major carbon isotope perturbations. The most extreme of these, the ∼570 Ma Shuram/DOUNCE (Doushantuo Negative Carbon isotope Excursion) anomaly, coincided with early radiations of benthic macrofauna linked to a temporary expansion in the extent of oxygenated seawater. Here we document an earlier negative ex...

The early Toarcian (~183 Ma) was characterized by a prominent volcanism-induced warming event associated with a massive addition of ¹²C-enriched carbon to the ocean-atmosphere system. This warming likely contributed to marked ocean deoxygenation during this time, giving the event its name: the early Toarcian oceanic anoxic event (T-OAE). Although t...

Exceptional magmatic events coincided with the largest mass extinctions throughout Earth’s history. Extensive degassing from organic-rich sediments intruded by magmas is a possible driver of the catastrophic environmental changes, which triggered the biotic crises. One of Earth’s largest magmatic events is represented by the Central Atlantic Magmat...

Extinction rates in the modern world are currently at their highest in 66 million years and are likely to increase with projections of future climate change. Our knowledge of modern-day extinction risk is largely limited to decadal-centennial terrestrial records, while data from the marine realm is typically applied to high-order (> 1 million year)...

Extinction rates in the modern world are currently at their highest in 66 million years and are likely to increase with projections of future climate change. Our knowledge of modern-day extinction risk is largely limited to decadal-centennial terrestrial records, while data from the marine realm is typically applied to high-order (> 1 million year)...

The Mozambique continental margin experienced large variations in sedimentation rates, primarily due to re-routing of sediment deposition from the Zambezi River during the last glacial-Holocene transition. As changes in sediment accumulation and organic matter deposition impose a strong control on the formation of authigenic minerals in the sedimen...

The Carnian Pluvial Episode (Late Triassic) was a time of global environmental changes and possibly substantial coeval volcanism. The extent of the biological turnover in marine and terrestrial ecosystems is not well understood. Here, we present a meta-analysis of fossil data that suggests a substantial reduction in generic and species richness and...

The role of ocean anoxia as a cause of the end-Triassic marine mass extinction is widely debated. Here, we present carbonate-associated sulfate d34S data from sections spanning the Late Triassic–Early Jurassic transition, which document synchronous large positive excursions on a global scale occurring in ~50 thousand years. Biogeochemical modeling...

Carbon and oxygen isotopes (δ13C and δ18O) in tree rings are widely used to reconstruct palaeoclimate variables such as temperature during the Holocene (12 thousand years ago - present), and are used increasingly in deeper time. However, their use is largely restricted to arboreal trees, which excludes potentially important data from prostrate tree...

Oxygen deprivation and hydrogen sulfide toxicity are considered potent kill mechanisms during the mass extinction just before the Permian–Triassic boundary (~251.9 million years ago). However, the mechanism that drove vast stretches of the ocean to an anoxic state is unclear. Here, we present palaeoredox and phosphorus speciation data for a marine...

Records suggest that the Permo–Triassic mass extinction (PTME) involved one of the most severe terrestrial ecosystem collapses of the Phanerozoic. However, it has proved difficult to constrain the extent of the primary productivity loss on land, hindering our understanding of the effects on global biogeochemistry. We build a new biogeochemical mode...

Large Igneous Province eruptions coincide with many major Phanerozoic mass extinctions, suggesting a cause-effect relationship where volcanic degassing triggers global climatic changes. In order to fully understand this relationship, it is necessary to constrain the quantity and type of degassed magmatic volatiles, and to determine the depth of the...

The Early Toarcian was characterised by the eruption of the Karoo-Ferrar large igneous province (LIP), rapid global warming, significant perturbations in the global carbon cycle, the development of widespread anoxia known as the Early Toarcian Oceanic Anoxic Event (T-OAE) and a biotic crisis in the marine realm known as the Early Toarcian Mass Exti...

The Early Toarcian was characterised by the eruption of the Karoo-Ferrar large igneous province (LIP), rapid global warming, significant perturbations in the global carbon cycle, the development of widespread anoxia known as the Early Toarcian Oceanic Anoxic Event (T-OAE) and a biotic crisis in the marine realm known as the Early Toarcian Mass Exti...

Flood basalt volcanism represented by the Kalkarindji Province(Australia) is temporally associated with a trilobite mass extinction at the Cambrian Series 2 – Series 3 boundary, providing one of the oldest potential links between volcanism and biotic crisis in the Phanerozoic. However, the relative timing of flood basalt volcanism (Kalkarindji Prov...

The shell material of marine benthic bivalves provides a sensitive archive of water chemistry immediately above the sediment–water interface, which in turn is affected by sedimentary geochemistry and redox reactions. Sulfate has a major controlling effect on sedimentary carbon cycling, particularly the processes of methane production and oxidation,...

The apparent lag between the first permanent rise of atmospheric oxygen to appreciable levels and oxygenation of the deep ocean has focused efforts in deciphering the evolution of seawater chemistry across the Proterozoic Eon (2.5–0.542 Ga). It is generally accepted that from ∼1.85 Ga oxic shallow marine waters were widespread while the deep ocean...

Eutrophication is a globally significant challenge facing freshwater ecosystems and is closely associated with anthropogenic enrichment of phosphorus (P) in the aquatic environment. Phosphorus inputs to rivers are usually dominated by diffuse sources related to farming activities and point sources such as waste water treatment works (WwTW). The lim...

Shell-bound organic matter (SBOM) is present in the shells of biomineralizing organisms and can act as an isotopic proxy for nutrition. Stable isotope analysis of SBOM generally requires its isolation from the mineral component of the shell, and this study shows that various shell removal techniques (cation exchange resin, ethylenediaminetetraaceti...

One of the most expanded records to contain the final fortunes of ammonoid cephalopods is within the López de Bertodano Formation of Seymour Island, James Ross Basin, Antarctica. Located at ~65º South now, and during the Cretaceous, this sequence is the highest southern latitude onshore outcrop containing the Cretaceous–Paleogene (K–Pg) transition....

It is generally accepted that wide stretches of the world's oceans turned anoxic during the Permian-Triassic transition. Although it is often invoked that these anoxic regions experienced an extreme redox state signified by free hydrogen sulfide in the water column (euxinia), recent studies employing iron speciation suggest that some regions were a...

The Cretaceous–Paleogene (K–Pg) mass extinction event 66 million years ago led to large changes to the global carbon cycle, primarily via a decrease in primary or export productivity of the oceans. However, the effects of this event and longer-term environmental changes during the Late Cretaceous on the global sulfur cycle are not well understood....

We test whether chemosymbiotic bivalves with sulphide-oxidizing bacteria record their nutritional strategy in the sulphur isotope composition of the carbonate-associated sulphate (CAS) in their shells, as a possible indicator of thiotrophic chemosymbiosis in the fossil record. The hypothesis rests on the possible incorporation of 34S-depleted sulph...

A negative shift in the calcium isotopic composition of marine carbonate rocks spanning the end-Permian extinction horizon in South China has been used to argue for an ocean acidification event coincident with mass extinction. This interpretation has proven controversial, both because the excursion has not been demonstrated across multiple, widely...

Fossil-bearing deposits in the Transantarctic Mountains, Antarctica indicate that, despite the cold nature of the continent’s climate, a tundra ecosystem grew during periods of ice sheet retreat in the mid to late Neogene (17–2.5 Ma), 480 km from the South Pole. To date, palaeotemperature reconstruction has been based only on biological ranges, the...

The measurement of isotope ratios in sedimentary rocks deposited over geological time can 6 provide key insights to past environmental change over important intervals in the past. However, it is 7 important to be aware that secondary alteration can overprint the original isotopic records. We demonstrate 8 this principle using high-resolution carbon...

The measurement of isotope ratios in sedimentary rocks deposited over geological time can provide key insights to past environmental change over important intervals in the past. However, it is important to be aware that secondary alteration can overprint the original isotopic records. We demonstrate this principle using high-resolution carbon, sulf...

Various studies report substantial increases in intrinsic water-use efficiency (W i ), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in W...

Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic c...

The recognition of a long-term negative carbon isotope trend straddling the Permian-Triassic boundary beds is widely accepted 1,2. Equally important is the notion that superimposed second-order scatter marks this geochemical record, hindering high-resolution intra-and inter-basinal correlation attempts 1,2. A more in-depth understanding of the natu...

Bulk-carbonate carbon isotope measurements are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorg...

Bulk-carbonate stable carbon isotope records are used to proxy the ancient biogeochemical carbon cycle as well as aid in determining the age of sedimentary deposits. However, the multicomponent nature and the component-specific diagenetic potential of bulk-rock pose limits on the applicability of this proxy in recording ancient seawater chemistry a...

The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2-Series 3 boundary. Like many other crises, it coincided with a negative carbon isotope excursion but the associated palaeoenvironmental changes remain unclear. To investigate the causal mechanism for this event, we report facies changes, pyrite framboid petrograph...

Seymour Island, in the James Ross Basin, Antarctica, contains a continuous succession of latest Cretaceous sediments deposited in a shallow marine environment at high latitude, making it an ideal place to study environmental changes prior to the K–Pg mass extinction. We measured major and trace elements and conducted petrographic analysis of two se...

The Cambrian Series 2- 3 boundary marks the first mass extinction of the Phanerozoic and, like many other extinction intervals, coincides with a negative inorganic carbon isotope excursion (ROECE) and the eruption of a large igneous province (Kalkarindji LIP). In the western Great Basin (USA) the extinction of the olenellid trilobites lies within a...