Philippe ClaeysVrije Universiteit Brussel | VUB · Archaeology, Environmental changes & Geo-Chemistry (AMGC)
Philippe Claeys
PhD University of California at Davis
Head of research group Archaeology, Environmental changes & Geo-Chemistry (AMGC).
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599
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Introduction
Philippe Claeys is a geologist, planetary scientist, geochemist documenting global changes & consequences of asteroid/comet impacts on the evolution of the bio-geosphere. PhD 1993 University of California at Davis, on the discovery of the Chicxulub crater. Postdoc at UCLA, before becoming a researcher at UC Berkeley for several years with Walter Alvarez. In the late nineties, Museum of Natural History in Berlin as chief scientist. Since 2001, he is a professor at the “Vrije Universiteit Brussel”
Additional affiliations
Education
July 1989 - April 1993
August 1987 - June 1989
Publications
Publications (599)
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...
The Cretaceous−Paleogene boundary is marked by a large impact and coeval mass extinction event that occurred 66 m.y. ago. Contemporaneous emplacement of the volcanic Deccan Traps also affected global climate before, during, and after the mass extinction. Many questions remain about the timing and eruption rates of Deccan volcanism, its precise forc...
The processes of planetary accretion and differentiation, whereby an unsorted mass of primitive solar system material evolves into a body composed of a silicate mantle and metallic core, remain poorly understood. Mass‐dependent variations of the isotope ratios of non‐traditional stable isotope systems in meteorites are known to record events in the...
An impact at Chicxulub, Mexico, occurred 66 million years ago, producing a global stratigraphic layer that marks the boundary between the Cretaceous and Paleogene eras. That layer contains elevated concentrations of platinum-group elements, including ruthenium. We measured ruthenium isotopes in samples taken from three Cretaceous-Paleogene boundary...
The Chicxulub asteroid impact event at the Cretaceous-Paleogene (K-Pg) boundary ~66 Myr ago is widely considered responsible for the mass extinction event leading to the demise of the non-avian dinosaurs. Short-term cooling due to massive release of climate-active agents is hypothesized to have been crucial, with S-bearing gases originating from th...
The existence of ice-edge phytoplankton blooms in the Southern Ocean is well described, yet direct observations of the mechanisms of phytoplankton bloom development following seasonal sea-ice melt remain scarce. This study constrains such responses using biological and biogeochemical datasets collected along a coastal-to-offshore transect that bise...
Early to middle Ediacaran organic-rich black shales host several famous fossil biotas and provide key evidence for understanding the coevolution of multicellular organisms and palaeoceanic environment. The water column redox states play critical roles in organic-rich shale deposition. Amongst multiple geochemical redox indexes, iron-speciation chem...
Documenting the seasonal temperature cycle constitutes an essential step toward mitigating risks associated with extreme weather events in a future warmer world. The mid-Piacenzian Warm Period (mPWP), 3.3 to 3.0 million years ago, featured global temperatures approximately 3°C above preindustrial levels. It represents an ideal period for directed p...
Upon passage through Earth's atmosphere, micrometeorites undergo variable degrees of melting and evaporation. Among the various textural and chemical groups recognized among cosmic spherules, that is, melted micrometeorites, a subset of particles may indicate anomalously high degrees of vaporization based on their chemical and isotopic properties....
More than 60% of meteorite finds on Earth originate from Antarctica. Using a data-driven analysis that identifies meteorite-rich sites in Antarctica, we show climate warming causes many extraterrestrial rocks to be lost from the surface by melting into the ice sheet. At present, approximately 5,000 meteorites become inaccessible per year (versus ~1...
The anisotropic textures, including unidirectional solidification textures and graphic intergrowths, characteristic for pegmatites, are interpreted to result from disequilibrium crystallization at high degrees of undercooling. Experimental studies have revealed the existence of thin boundary layers surrounding the rapidly growing crystals. Here, to...
Repeated carbon isotope excursions and widespread organic-rich shale deposition mark the Middle and Upper 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 oceans to the development of anoxia, but their repeated nature sugges...
Stable isotope sclerochemistry of mollusks and otoliths is frequently used for the reconstruction of paleotemperature and seasonality. Constraints on the paleoecology and –environment of these organisms, and how these factors influence intra-and inter-taxon isotope variability and variation, are thus highly valuable. We measured seasonal changes in...
The occurrence of forsteritic olivine in EH enstatite chondrites is indicative of bulk disequilibrium. In MgO‐rich magmatic systems, forsterite can either crystallize as a liquidus phase or be produced during peritectic melting of enstatite. Because diffusion of divalent cations through forsterite is relatively rapid, it records peak melting (i.e.,...
This study presents a methodological advancement in the field of clumped‐isotope (∆47) thermometry, specifically tailored for application to freshwater ostracods. The novel ostracod clumped isotope approach enables quantitative temperature and hydrological reconstruction in lacustrine records. The relationship between ∆47 and the temperature at whi...
Constraining the thermodynamic conditions within an impact structure during and after hypervelocity impacts is extremely challenging due to the transient thermal regimes. This work uses carbonate clumped-isotope thermometry to reconstruct absolute temperatures of impact lithologies within and close to the ∼66 Myr old Chicxulub crater (Yucatán, Méxi...
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 (kilometer scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates ar...
This study shows, for the first time, the absence of a vital effect in the clumped isotope carbonate (Δ47) fossil ostracod signal and confirms the ability of the novel ostracod-Δ47 thermometer to reconstruct past temperatures and hydrological conditions in complex lacustrine systems. Furthermore, the application of Δ47 analyses on the ostracod spec...
We provide a comprehensive overview of a reconnaissance expedition aimed at identifying new possible meteorite stranding zones in the surrounding of the Belgian Princess Elisabeth Antarctica (PEA) station in the Sør Rondane Mountains during the BELARE 2022-2023 field season. The team was composed of four scientists and one field guide. Several area...
Elemental mapping has been commonly used for the screening of geological samples, biological samples, and so on, using micro-X-ray fluorescence spectrometry, scanning electron microscopy in combination with energy-dispersive X-ray spectrometry, or electron probe micro analysis (EPMA). Most of these techniques are valuable for major elements, but th...
Documenting the seasonal temperature cycle constitutes an essential step towards mitigating risks associated with extreme weather events in a future warmer world. The mid-Piacenzian Warm Period (mPWP), 3.3 – 3.0 million years ago, featured global temperatures approximately 3°C above pre-industrial levels. It represents an ideal period for directed...
Since the first systematic meterotie recovery expedition in Antarctica was conducted in 1973 and followed by expeditions until the present, the Antarctic meteorite collection plays a pivotal role for cosmochemichemistry as the recovered fragments constitute by number more than 60% of the population of all meteorites collected to date. Meteorites ac...
The Chicxulub impact is thought to have triggered a global winter at the Cretaceous-Palaeogene (K-Pg) boundary 66 million years ago. Yet the climatic consequences of the various debris injected into the atmosphere following the Chicxulub impact remain unclear, and the exact killing mechanisms of the K-Pg mass extinction remain poorly constrained. H...
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....
Introduction
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 identify volumes of carbonate precipitated by these organisms at precise intervals during the experi...
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...