Bone histology of acipenseriform fishes reveals seasonality during the final years of the Mesozoic.

Abstract The Cretaceous-Paleogene (KPg) mass extinction ~66 million years ago (Ma) was triggered by the Chicxulub impact on the present-day Yucatán Peninsula. This event caused the extinction of circa 76% of species, including all non-avian dinosaurs, and represents one of the most selective extinctions to date. The timing of the impact and its aftermath have mainly been studied on millennial timescales, leaving the season of the impact unconstrained. Here, we demonstrate that the impact that caused the KPg mass extinction took place during boreal spring. Osteohistology and stable isotope records of exceptionally preserved dermal and perichondrial bones in acipenseriform fishes from the Tanis impact-induced seiche deposits reveal annual cyclicity across the final years of the Cretaceous. These fishes ultimately perished in boreal spring. Annual life cycles, involving seasonal timing and duration of reproduction, feeding, hibernation, and aestivation, vary strongly across latest Cretaceous biotic diversity. We conclude that the timing of the Chicxulub impact in boreal spring significantly influenced selective biotic survival across the KPg boundary.

Download Full-text

Deposition and age of Chicxulub impact spherules on Gorgonilla Island, Colombia

Geological Society of America Bulletin ◽

10.1130/b35287.1 ◽

2019 ◽

Vol 132 (1-2) ◽

pp. 215-232

Author(s):

Paula Mateo ◽

Gerta Keller ◽

Thierry Adatte ◽

André M. Bitchong ◽

Jorge E. Spangenberg ◽

...

Keyword(s):

Mass Extinction ◽

Tectonic Activity ◽

Sea Level Fluctuations ◽

Variable Extent ◽

Stratigraphic Position ◽

Radiolarian Biostratigraphy ◽

Absolute Age ◽

Chicxulub Impact ◽

The Impact ◽

Primary Impact

AbstractThe end-Cretaceous mass extinction (66 Ma) has long been associated with the Chicxulub impact on the Yucatan Peninsula. However, consensus on the age of this impact has remained controversial because of differing interpretations on the stratigraphic position of Chicxulub impact spherules relative to the mass extinction horizon. One side argues that the impact occurred precisely at the Cretaceous-Paleogene boundary, thus coinciding with the mass extinction; the other side argues that the impact predated the Cretaceous-Paleogene boundary, based on the discovery of primary impact spherules deposits in NE Mexico and Texas near the base of planktic foraminiferal zone CF1, dated at 170 k.y. before the Cretaceous-Paleogene boundary. A recent study of the most pristine Chicxulub impact spherules discovered on Gorgonilla Island, Colombia, suggested that they represent a primary impact deposit with an absolute age indistinguishable from the Cretaceous-Paleogene boundary. Here, we report on the Gorgonilla section with the main objective of evaluating the nature of deposition and age of the spherule-rich layer relative to the Cretaceous-Paleogene boundary.The Gorgonilla section consists of light gray-yellow calcareous siliceous mudstones (pelagic deposits) alternating with dark olive-brown litharenites (turbidites). A 3-cm-thick dark olive-green spherule-rich layer overlies an erosional surface separating Maastrichtian and Danian sediments. This layer consists of a clast-supported, normally graded litharenite, with abundant Chicxulub impact glass spherules, lithics (mostly volcanic), and Maastrichtian as well as Danian microfossils, which transitions to a calcareous mudstone as particle size decreases. Mineralogical analysis shows that this layer is dominated by phyllosilicates, similar to the litharenites (turbidites) that characterize the section. Based on these results, the spherule-rich layer is interpreted as a reworked early Danian deposit associated with turbiditic currents. A major hiatus (>250 k.y.) spanning the Cretaceous-Paleogene boundary and the earliest Danian is recorded at the base of the spherule-rich layer, based on planktic foraminiferal and radiolarian biostratigraphy and carbon stable isotopes. Erosion across the Cretaceous-Paleogene boundary has been recorded worldwide and is generally attributed to rapid climate changes, enhanced bottom-water circulation during global cooling, sea-level fluctuations, and/or intensified tectonic activity. Chicxulub impact spherules are commonly reworked and redeposited into younger sediments overlying a Cretaceous-Paleogene boundary hiatus of variable extent in the Caribbean, Central America, and North Atlantic, while primary deposits are rare and only known from NE Mexico and Texas. Because of their reworked nature, Gorgonilla spherules provide no stratigraphic evidence from which the timing of the impact can be inferred.

Download Full-text

Deccan Volcanism or the Chicxulub Impact: The Chicken or Egg Question

10.5194/egusphere-egu2020-22414 ◽

2020 ◽

Author(s):

Gerta Keller

Keyword(s):

Mass Extinction ◽

Impact Crater ◽

Global Climate ◽

Mass Extinctions ◽

Deccan Volcanism ◽

Asteroid Impact ◽

Global Climate Warming ◽

Chicxulub Impact Crater ◽

Chicxulub Impact ◽

The Impact

The Cretaceous&#8211;Paleogene boundary (KTB or KPB) mass extinction is primarily known for the demise of the dinosaurs, the Chicxulub impact, and the rancorous forty-year-old controversy over the cause of this mass extinction. For the first 30 years, the controversy primarily revolved around the age of the impact claimed as precisely KTB based on the assumption that it caused the mass extinction. The iridium (Ir) anomaly at the KTB was claimed proof of the asteroid impact, but no Ir was ever associated with impact evidence and recent findings reveal no extraterrestrial component in PGEs or the KTB Ir anomaly. Impact melt rock glass spherules are also claimed as indisputable evidence of the KTB age impact, but such spherule layers are commonly reworked from the primary (oldest) layer in late Maastrichtian, KTB and Danian sediments; thus only the oldest impact spherule layer documented near the base of zone CF1 ~200 ky below the KTB can approximate the impact&#8217;s age. Similarly, the impact breccia in the Chicxulub impact crater predates the KTB. The best age derived from Ar/Ar dating of impact glass spherules is within 200 ky of the KTB and thus no evidence for the KTB age. All evidence strongly suggests the Chicxulub impact most likely predates the mass extinction ~ 200 ky and played no role in it. Deccan volcanism (LIP) was dismissed as potential cause or even contributor to the KTB mass extinction despite the fact that all other mass extinctions are associated with Large Igneous Province (LIP) volcanism but none with an asteroid impact. During the last decade, Deccan volcanism gained credence based on a succession of discoveries: 1) the mass extinction in between the longest Deccan lava flows across India; 2) high-precision dating of the entire sequence of Deccan volcanism based on UPb zircon dating; 3) recognition of four distinct eruption pulses all related to global climate warming with the largest pulse beginning 20 ky prior to and ending at the KTB; 4) Identifying the climate link to Deccan volcanism based on age dating and mercury from Deccan eruptions in marine sediments; and 5) Identifying the KTB mass extinction directly related to the major Deccan eruption pulse, hyperthermal warming and ocean acidification all linked to global mercury fallout from Deccan eruptions in marine sediments. Despite this remarkable culmination of evidence, the controversy continues with impact proponents arguing that Deccan volcanism didn&#8217;t exist at the KTB &#8211; the impact was the sole cause.

Download Full-text

The Boltysh impact structure: An early Danian impact event during recovery from the K-Pg mass extinction

Science Advances ◽

10.1126/sciadv.abe6530 ◽

2021 ◽

Vol 7 (25) ◽

pp. eabe6530

Author(s):

Annemarie E. Pickersgill ◽

Darren F. Mark ◽

Martin R. Lee ◽

Simon P. Kelley ◽

David W. Jolley

Keyword(s):

Mass Extinction ◽

Crater Lake ◽

Temporal Association ◽

Earth System ◽

Impact Event ◽

The Earth ◽

Relationship Of ◽

Chicxulub Impact ◽

The Impact ◽

Impact Events

Both the Chicxulub and Boltysh impact events are associated with the K-Pg boundary. While Chicxulub is firmly linked to the end-Cretaceous mass extinction, the temporal relationship of the ~24-km-diameter Boltysh impact to these events is uncertain, although it is thought to have occurred 2 to 5 ka before the mass extinction. Here, we conduct the first direct geochronological comparison of Boltysh to the K-Pg boundary. Our 40Ar/39Ar age of 65.39 ± 0.14/0.16 Ma shows that the impact occurred ~0.65 Ma after the mass extinction. At that time, the climate was recovering from the effects of the Chicxulub impact and Deccan trap flood volcanism. This age shows that Boltysh has a close temporal association with the Lower C29n hyperthermal recorded by global sediment archives and in the Boltysh crater lake sediments. The temporal coincidence raises the possibility that even a small impact event could disrupt recovery of the Earth system from catastrophic events.

Download Full-text

Globally distributed iridium layer preserved within the Chicxulub impact structure

Science Advances ◽

10.1126/sciadv.abe3647 ◽

2021 ◽

Vol 7 (9) ◽

pp. eabe3647

Author(s):

Steven Goderis ◽

Honami Sato ◽

Ludovic Ferrière ◽

Birger Schmitz ◽

David Burney ◽

...

Keyword(s):

Mass Extinction ◽

Depositional Environment ◽

Hypervelocity Impact ◽

Impact Structure ◽

Impact Event ◽

Post Impact ◽

Temporal Horizon ◽

Chicxulub Impact ◽

The Impact ◽

Globally Distributed

The Cretaceous-Paleogene (K-Pg) mass extinction is marked globally by elevated concentrations of iridium, emplaced by a hypervelocity impact event 66 million years ago. Here, we report new data from four independent laboratories that reveal a positive iridium anomaly within the peak-ring sequence of the Chicxulub impact structure, in drill core recovered by IODP-ICDP Expedition 364. The highest concentration of ultrafine meteoritic matter occurs in the post-impact sediments that cover the crater peak ring, just below the lowermost Danian pelagic limestone. Within years to decades after the impact event, this part of the Chicxulub impact basin returned to a relatively low-energy depositional environment, recording in unprecedented detail the recovery of life during the succeeding millennia. The iridium layer provides a key temporal horizon precisely linking Chicxulub to K-Pg boundary sections worldwide.

Download Full-text

Severe perturbations of the marine biosphere following the Chicxulub impact

10.5194/egusphere-egu2020-8025 ◽

2020 ◽

Author(s):

Georg Feulner ◽

Julia Brugger ◽

Matthias Hofmann ◽

Stefan Petri

Keyword(s):

Nutrient Availability ◽

Primary Productivity ◽

Mass Extinction ◽

Net Primary Productivity ◽

Ocean Model ◽

Sulfate Aerosols ◽

Surface Cooling ◽

Chicxulub Impact ◽

The Impact ◽

Marine Biosphere

Among the "big five" mass-extinction events during the Phanerozoic, the end-Cretaceous extinction 66 million years ago is particularly well known because it marks the demise of the non-avian dinosaurs. Evidence for the Chicxulub impact as the primary cause of this mass extinction has been accumulating over the past four decades, but there are still many open questions regarding the detailed course of events.Building on our earlier modelling results demonstrating strong global cooling due to sulfate aerosols formed in the wake of the Chicxulub impact (Brugger, Feulner & Petri 2017, Geophys. Res. Lett., 44:419-427), we here explore the response of the ocean in more detail. Specifically, we added a marine biogeochemistry module to a coupled atmosphere-ocean model to investigate the effects of the impact on ocean geochemistry and primary productivity.We find that the formation of stratospheric sulfate aerosols leads to a marked decrease in annual global mean surface air temperatures by at least 26&#176;C in the coldest year after the impact, returning to pre-impact temperatures after about one century. The strong surface cooling induces vigorous ocean mixing that leads to changes in oxygen distributions and nutrient availability. Due to the darkness, marine net primary productivity essentially shuts down in the first years after the impact. Once the light returns, however, we find a significant increase in primary productivity caused by a surge in nutrient availability, both due to upwelling in the ocean and delivery by the impactor. These strong perturbations of the marine biosphere further support the notion that the impact played a decisive role in the end-Cretaceous mass extinction.

Download Full-text

Paroxysmal Deccan Eruptions linked to End-Cretaceous Mass Extinction

10.5194/egusphere-egu21-10700 ◽

2021 ◽

Author(s):

Thierry Adatte ◽

Gerta Keller ◽

Jorge E. Spangenberg ◽

Paula Mateo ◽

Jahnavi Punekar ◽

...

Keyword(s):

Mass Extinction ◽

Environmental Changes ◽

Global Climate ◽

Volcanic Eruptions ◽

Mass Extinctions ◽

Deccan Volcanism ◽

Time Resolved ◽

Global Climate Changes ◽

Chicxulub Impact ◽

The Impact

The Chicxulub impact in Mexico and Deccan volcanism in India are both linked to the end-Cretaceous mass extinction but the relative timing of the impact, volcanic eruptions, and environmental changes remain controversial, precluding a full assessment of their respective roles. Mercury anomalies within the stratigraphic record have recently been proposed as atmospheric fallout of continental large igneous provinces (LIPs), and these anomalies are associated with all five major mass extinctions in Earth&#8217;s history. If this proxy is robust, it could provide a record of volcanism directly correlated to mass extinctions and in the case of the End-extinction, the Chicxulub impact. To test this hypothesis, we analyzed mercury in the late Maastrichtian from the base of C29r to the Cretaceous-Paleogene boundary (KPB) n the astronomically tuned Elles section in Tunisia, and correlate this chemostratigraphic record with recent high-precision U-Pb geochronology of Deccan volcanism. Our results support that Hg is a robust indicator of LIP volcanism, and directly links Deccan volcanism to rapid global climate changes, ocean acidification and increasing environmental stress during the last 320-340 kyr of the Maastrichtian. Furthermore, our time-resolved Hg record and U-Pb resolved eruption volumes reveal paroxysmal volcanic eruptions (~30% by volume) during the final 35 kyr leading up to the KPB mass extinction.

Download Full-text

Differential human impact on the survival of genetically distinct avian lineages

Bird Conservation International ◽

10.1017/s0959270900002264 ◽

1999 ◽

Vol 9 (2) ◽

pp. 147-154 ◽

Cited By ~ 12

Author(s):

Austin L. Hughes

Keyword(s):

Human Impact ◽

Physical Environment ◽

Mass Extinction ◽

The Earth ◽

Biotic Diversity ◽

Extinction Event ◽

Mass Extinction Event ◽

Extinction Events ◽

The Impact ◽

Mass Extinction Events

SummaryAt the present time the earth is facing an anthropogenic (human-caused) mass extinction event that may eventually rival previous mass extinction events caused by drastic changes i n the physical environment; however, the impact of this event on the earth's biotic diversity remains difficult to predict. Patterns of extinction and endangerment in birds, one of the best known taxonomically among major groups of organisms, showed that the distribution of human impact has been non-uniform relative to phylogenetic relationships. Fifteen major avian lineages differed over 35-fold with respect to the frequency of historical extinction and over threefold with respect to frequency of current threat; and overall rates of both extinction and threat were significantly higher in non-passerine orders than in passerines. Moreover, among both passerines and non-passerines, the rate of historic extinction has been significantly higher for species in monotypic genera than for other species; and in passerines, the rate of current threat is significantly higher for species in monotypic genera than for other species. Thus, the anthropogenic extinction and threat to avian species has specifically targeted species that are phylogenetically and thus, presumably genetically, unique.

Download Full-text

Seasonal calibration of the end-cretaceous Chicxulub impact event

Scientific Reports ◽

10.1038/s41598-021-03232-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Robert A. DePalma ◽

Anton A. Oleinik ◽

Loren P. Gurche ◽

David A. Burnham ◽

Jeremy J. Klingler ◽

...

Keyword(s):

Mass Extinction ◽

Insect Behavior ◽

Global Scale ◽

Impact Event ◽

Growth Band ◽

Isotopic Analyses ◽

Timing Data ◽

Post Impact ◽

Chicxulub Impact ◽

The Impact

AbstractThe end-Cretaceous Chicxulub impact triggered Earth’s last mass-extinction, extinguishing ~ 75% of species diversity and facilitating a global ecological shift to mammal-dominated biomes. Temporal details of the impact event on a fine scale (hour-to-day), important to understanding the early trajectory of mass-extinction, have largely eluded previous studies. This study employs histological and histo-isotopic analyses of fossil fish that were coeval with a unique impact-triggered mass-death assemblage from the Cretaceous-Paleogene (KPg) boundary in North Dakota (USA). Patterns of growth history, including periodicity of ẟ18O and ẟ13C and growth band morphology, plus corroborating data from fish ontogeny and seasonal insect behavior, reveal that the impact occurred during boreal Spring/Summer, shortly after the spawning season for fish and most continental taxa. The severity and taxonomic symmetry of response to global natural hazards are influenced by the season during which they occur, suggesting that post-impact perturbations could have exerted a selective force that was exacerbated by seasonal timing. Data from this study can also provide vital hindsight into patterns of extant biotic response to global-scale hazards that are relevant to both current and future biomes.

Download Full-text

Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

Sustainability ◽

10.3390/su13105726 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5726

Author(s):

Aleksandra Wewer ◽

Pinar Bilge ◽

Franz Dietrich

Keyword(s):

Life Cycle ◽

Lithium Ion Batteries ◽

Electric Vehicles ◽

Energy Demand ◽

Lithium Ion ◽

Life Cycles ◽

Future Research ◽

Research Areas ◽

Study Results ◽

The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

Download Full-text

Effect of Barley Sowing Density on the Integrated Weed Management of Lolium rigidum (Annual Ryegrass) in Mediterranean Dryland: A Modeling Approach

Agronomy ◽

10.3390/agronomy11081565 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1565

Author(s):

María Belén D’Amico ◽

Guillermo R. Chantre ◽

Guillermo L. Calandrini ◽

José L. González-Andújar

Keyword(s):

Weed Management ◽

Life Cycles ◽

Integrated Weed Management ◽

Future Research ◽

Seed Removal ◽

Weed Infestation ◽

High Control ◽

Weed Dynamics ◽

The Impact

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.

Download Full-text