Philippe Claeys

Vrije Universiteit Brussel | VUB · Archaeology, Environmental changes & Geo-Chemistry (AMGC)

Drilling into Chicxulub's formation The Chicxulub impact crater, known for its link to the demise of the dinosaurs, also provides an opportunity to study rocks from a large impact structure. Large impact craters have “peak rings” that define a complex crater morphology. Morgan et al. looked at rocks from a drilling expedition through the peak rings...

The Cretaceous-Paleogene boundary ~65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy acro...

The passage of a comet shower ~35 million years ago is generally advocated to explain the coincidence during Earth's late Eocene of an unusually high flux of interplanetary dust particles and the formation of the two largest craters in the Cenozoic, Popigai and the Chesapeake Bay. However, new platinum-group element analyses indicate that Popigai w...

Observations on shocked quartz in Cretaceous-Tertiary (K-T) boundary sediments compellingly tied to Chicxulub crater raise three problems. First, in North America shocked quartz occurs above the main K-T ejecta layer. Second, shocked quartz is more abundant west than east of Chicxulub. Third, shocked quartz reached distances requiring initial veloc...

40Ar/39Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded well-behaved incremental heating spectra with a mean plateau age of 64.98 ± 0.05 million years ago (Ma). The glassy melt rock of andesitic composi...

In this study we show, for the first time, the absence of a vital effect in the clumped isotope carbonate (Δ47) fossil ostracod signal, as well as the ability of the novel ostracod-Δ47 thermometer to reconstruct past hydrological conditions in complex lacustrine systems. Furthermore, through the application of Δ47 analyses on the ostracod species C...

This study presents the ostracod clumped-isotope (∆47) thermometer, a new tool that provides quantitative temperature and hydrological reconstruction from lacustrine systems, which are among the best archives to reconstruct continental paleotemperature variations. The relationship between ∆47 and the temperature at which ostracod shell crystallized...

Repeated carbon isotope excursions and widespread organic-rich shale deposition mark the Middle and Late Devonian series. Various explanations such as extensive volcanism and land plant evolution have been given for these perturbations and the general sensitivity of the Devonian to oceanic anoxia, but their repeated nature suggests that astronomica...

New stalagmites from Qadisha Cave (Lebanon) located at 1720 m above sea level provide a high-resolution and well-dated record for north- ern Mount Lebanon. The stalagmites grew discontinuously from 9.2 to 5.7 and at 3.5 ka, and they show a tendency to move from a more negative oxygen isotope signal at ∼9.1 ka to a more positive signal at ∼5.8 ka. S...

A series of publications purport to provide evidence that the Earth was subjected to an extraterrestrial event or events at ~12.9 ka creating an environmental cataclysm and the onset of the Younger Dryas stadial. The varied and sometime conflicting speculations in those publications have become known collectively as the “Younger Dryas Impact Hypoth...

The chemical effects of terrestrial alteration, with a particular focus on lithophile trace elements, were studied for a set of H chondrites displaying various degrees of weathering from fresh falls to altered finds collected from hot deserts. According to their trace element distributions, a considerable fraction of rare earth elements (REEs), Th,...

Bivalves record seasonal environmental changes in their shells, making them excellent climate archives. However, not every bivalve can be used for this end. The shells have to grow fast enough so that micrometre- to millimetre-sampling can resolve sub-annual changes. Here, we investigate whether the bivalve Angulus benedeni benedeni is suitable as...

The Valanginian Weissert Event (ca. 134.5 Ma) has long been linked to emplacement of the Paraná-Etendeka large igneous province (LIP). Although several Mesozoic crises were triggered by volcanic CO2 emissions and global warming, causing oceanic oxygen depletion, the Weissert Event featured climate cooling and limited marine anoxia. Here, the impact...

We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric ¹⁰ Be, εNd, ⁸⁷ Sr/ ⁸⁶ Sr) and organic material (C/N, δ ¹³ C), we characterize the source material, succession of previous glaciations and deglaciations and the paleoe...

Angrite meteorites are thought to represent ancient basaltic igneous rocks that formed inward of Jupiter’s orbit on the basis of their isotopic parameters such as ε⁵⁰Ti, ε⁵⁴Cr and Δ¹⁷O in addition to Fe/Mn ratios of pyroxene. New bulk oxygen isotope measurements of nine angrites, and of olivine ‘xenocrysts’ and groundmass fractions from three quenc...

The Antarctic ice sheet’s future contribution to sea level rise is difficult to predict, mostly because of the uncertainty and variability of the surface mass balance (SMB). Ice cores are used to locally (km scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates are high....

The barrow cemetery at Heath Wood, Derbyshire, is the only known Viking cremation cemetery in the British Isles. It dates to the late ninth century and is associated with the over-wintering of the Viking Great Army at nearby Repton in AD 873-4. Only the cremated remains of three humans and of a few animals are still available for research. Using st...

Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to its southerly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strength and latitudinal position changed during the Holocene, leading thus to different responses of the vegetation to past climate changes...

Fast elemental mapping using laser ablation-inductively coupled plasma-time of flight-mass spectrometry (LA-ICP-TOF-MS) was applied to a set of chondritic meteorite samples, more specifically H chondrites. LA-ICP-TOF-MS enables element distribution maps for both major and trace elements to be obtained at mm order spatial resolution (5 × 5 mm square...

Growth experiments present a powerful tool for determining the effect of environmental parameters on growth and carbonate composition in biogenic calcifiers. For successful proxy calibration and biomineralization studies, it is vital to exactly identify volumes of carbonate precipitated at precise intervals during the experiment. Here, we investiga...

During the early medieval period (5th–9th century CE), the North Sea coastal societies were involved in long distance maritime trade relations, which resulted in a pronounced mobility of individuals throughout the North Sea area. This work presents the first isotope data from human remains on diet and mobility from early medieval Belgian coastal po...

Rudist shells are important archives for palaeoenvironmental reconstructions in the greenhouse world of the Cretaceous. Radiolitids, a family of rudists became very abundant dwellers of the shallow marine carbonate platforms during the Cretaceous. Still, due to the complex structure of their low-Mg calcite outer shell layer, radiolitids are often d...

Impact events that create complex craters excavate mid- to lower-crustal rocks, offering a unique perspective on the interior composition and internal dynamics of planetary bodies. On the Yucatán Peninsula, Mexico, the surface geology mainly consists of ~3 km thick sedimentary rocks, with a lack of exposure of crystalline basement in many areas. Co...

Obtaining temperature data from the mid-Piacenzian warm period (ca. 3 Ma, Pliocene epoch) is a key factor in outlining the impact of projected anthropogenic climate change. The mid-Piacenzian warm period was a high-CO2 world with a paleogeography similar to modern times. The time interval has been used to validate and improve climate model retrodic...

The end-Triassic extinction event (~ 201.5 Ma) is one of the five major mass extinction events in Earth's history, however, considerable discussion continues on the exact causes and timing of the event. This is because, whilst certain geochemical data on T-J sections appears to be largely comparable globally, with for example a significant (up to 6...

The Pliensbachian-Toarcian boundary event has a marked impact among nektonic, benthic, and planktonic communities seen by extinction of some taxa, changes in their diversity and in their species richness. This event resulted in belemnite body-size reduction in assemblages and dominant species at the Toarcian GSSP, but it remains unclear to what deg...

The Chicxulub impact triggered a global impact winter at the Cretaceous-Paleogene (K-Pg) boundary 66 million years ago. Yet, the exact killing mechanisms of the K-Pg mass extinction including the wipe-out of non-avian dinosaurs, remain poorly constrained. Here, we present paleoclimate simulations based on new sedimentological constraints from an ex...

To fully assess the resilience and recovery of life in response to the Cretaceous–Paleogene (K-Pg) boundary mass extinction ~ 66 million years ago, it is paramount to understand biodiversity prior to the Chicxulub impact event. The peak ring of the Chicxulub impact structure offshore the Yucatán Peninsula (México) was recently drilled and extracted...

The future contributions of the Antarctic Ice Sheet to sea level rise will depend on the evolution of its surface mass balance (SMB), which could amplify/dampen mass losses increasingly observed at the ice sheet's edge. In situ constraints of SMB over annual-to-decadal timescales consist mostly of firn/ice cores that have a surface footprint $\sim$...

We investigated the lithophile element budgets of both unequilibrated and equilibrated H chondrites using various in-situ techniques such as μXRF, EPMA, LA-ICP-TOF-MS, etc., addressing the effects of thermal metamorphism on their distributions.

The mid-Maastrichtian carbon isotope event (MME), dated at~69 Ma, reflects a perturbation of the global carbon cycle that, in part, correlates with the enigmatic global extinction of 'true' (i.e., non-tegulated) inoceramid bivalves. The mechanisms of this extinction event are still debated. While both the inoceramid extirpation and MME have been re...

The Pliocene sedimentary record provides a window into Earth's climate dynamics under warmer-than-present boundary conditions. However, the Pliocene cannot be considered a stable warm climate that constitutes a solid baseline for middle-of-the-road future climate projections. The increasing availability of time-continuous sedimentary archives (e.g....

La collection des iguanodons de Bernissart (Belgique) constitue l'un des plus grands ensembles de restes de dinosaures connus à ce jour dans le monde, et l'une des plus importantes découvertes de l'histoire de la paléontologie. La trentaine de spécimens d'Iguanodon extraite du gisement de 1878 à 1881 a permis des avancées considérables concernant l...

To expand traditional cyclostratigraphic numerical methods beyond their common technical limitations and apply them to truly deep-time archives, we need to reflect on the development of new approaches to sedimentary archives that are not traditionally targeted for cyclostratigraphic analysis but that frequently occur in the impoverished deep-time r...

Widespread marine anoxia triggered by the runoff and recycling of nutrients was a key phenomenon associated with the Frasnian–Famennian (FF) mass extinction. However, the relative importance of global‐scale processes versus local influences on site‐specific environmental change remains poorly understood. Here, nitrogen‐isotope (δ¹⁵N) trends are com...

Meteorites are invaluable tools to study the formation and the evolution of the solar system. However, by their fragile nature, and notably the presence of FeNi alloys, they can degrade very fast at the surface of the Earth. This underlines the importance of return sample missions with the aim to bring back pristine samples, but also urges us to in...

Meteorites are prone to errestrial weathering not only after their fall on the Earth’s surface but also during storage in museum collections. To study the susceptibility of this material to weathering, weathering experiments were carried out on polished sections of the H5 chondrite Asuka 10177. The experiments consisted of four 100‐days cycles duri...

This work presents isotopic data for the non-traditional isotope systems Fe, Cu, and Zn on a set of Chicxulub impactites and target lithologies with the aim of better documenting the dynamic processes taking place during hypervelocity impact events, as well as those affecting impact structures during the post-impact phase. The focus lies on materia...

The youngest time interval of the Cretaceous Period is known as the Maastrichtian, in reference to the shallow-marine strata outcropping in the area surrounding the city of Maastricht, in the Netherlands- Belgium border region. While the type-Maastrichtian strata have yielded a wealth of paleontological data, comparatively little geochemical work h...

Achondritic micrometeorites represent one of the rarest (ca. 0.5–2.1%) particle types among Antarctic micrometeorite collections. Here, we present major, trace element and oxygen isotope compositions on five vitreous, achondritic cosmic spherules (341–526 µm in size) recovered from the Widerøefjellet sedimentary trap in the Sør Rondane Mountains (S...

Catch Pim's talk on Wednesday 09/03/2022 at 3:35 pm CT !

The Cretaceous-Paleogene (K-Pg) boundary event, triggered by the Chicxulub asteroid impact in Mexico ∼66 Myr ago, is recognized as one of the major environmental crises in Earth's history. Its effects on the evolution of tropical vegetation were drastic, giving rise to the closed-canopy tropical rainforest. Despite of its importance, the actual K-P...

Micrometeorites experience varying degrees of evaporation and mixing with atmospheric oxygen during atmospheric entry. Evaporation due to gas drag heating alters the physicochemical properties of fully melted cosmic spherules (CSs), including the size, chemical and isotopic compositions and is thus expressed in its chemical and isotopic signatures....

Constraining the degree of preservation of a meteoritic signature within an impact structure provides vital insights in the complex pathways and processes that occur during and after an impact cratering event, providing information on the fate of the projectile. The IODP-ICDP Expedition 364 drilling recovered a ∼829 m continuous core (M0077A) of im...

Meteorites provide a unique view into the origin and evolution of the Solar System. Antarctica is the most productive region for recovering meteorites, where these extraterrestrial rocks concentrate at meteorite stranding zones. To date, meteorite-bearing blue ice areas are mostly identified by serendipity and through costly reconnaissance missions...

To expand traditional cyclostratigraphic numerical methods beyond their common technical limitations and apply them to truly deep-time archives we need to reflect on the development of new approaches to sedimentary archives that traditionally are not targeted for cyclostratigraphic analysis, but that frequently occur in the impoverished deep-time r...

Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to its southerly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strength and latitudinal position changed during the Holocene, leading thus to different responses of the vegetation to past climate changes...

Studies of funerary practices provide information about many aspects of death in past societies. However, only limited archaeological evidence documents the circumstances under which cremations occurred and the person(s) who were performing the funerary rituals. Lying at the border between Atlantic and Continental cultural traditions, the Scheldt a...

The Pliocene sedimentary record provides a window into Earth’s climate dynamics under warmer-than-present boundary conditions. However, the Pliocene cannot be considered a stable warm climate that constitutes a solid baseline for middle-road future climate projections. Indeed, the increasing availability of time-continuous sedimentary archives (e.g...

Rare earth elements (REEs) are universally used for understanding planetary processes such as silicate differentiation and are often considered to be relatively immobile. Despite this overall immobility, previous studies on the weathering effects on REEs have demonstrated that terrestrial weathering including Antarctic alteration can modify origina...

Cremation is a complex mortuary practice, involving a number of activities of the living towards the dead before, during, and after the destruction of the bodily soft tissues by fire. The limiting information concerning these behavioral patterns obtained from the pyre remains and/or cremation deposits prevents the reconstruction of the handling of...

This newsletter reports the classification of 821 meteorites collected from ice fields near the Yamato and Belgica Mountains by JARE-15, 20, 39, and 41 (Yamato 74, 79, 98, and 00, Belgica 98 meteorites) and from the Balchen and/or Nansen Ice Fields by JARE-29, 31, 51 and JARE-54/BELARE 2012-2013 (Asuka 87, 88, 90, 09, and 12 meteorites). JARE-51 an...

The Chicxulub impact caused a crash in productivity in the world's oceans which contributed to the extinction of ∼75% of marine species. In the immediate aftermath of the extinction, export produ