Richard A F Grieve

• DSc
• Professor (Associate) at Western University

One of the most common types of allochthonous impactite produced in hypervelocity impact events is impact breccia that contains melt particles. In numerous terrestrial hypervelocity impact structures such melt‐bearing breccias have been termed “suevite,” after the type locality at the Ries impact structure, Germany. Despite its widespread occurrenc...

The Offset Dykes of the ~1.85 Ga ~200 km-diameter Sudbury impact structure formed by the injection of impact melt from embayment structures in the Sudbury Igneous Complex (SIC) – the ~3–5 km thick impact melt sheet – into the footwall of the crater. Despite having been recognized over a century ago and being the sites for several world-class ore de...

Over the past few decades, it has become increasingly clear that the impact of interplanetary bodies on other planetary bodies is one of the most ubiquitous and important geological processes in the Solar System. This impact process has played a fundamental role throughout the history of the Earth and other planetary bodies, resulting in both destr...

Core from Hole M0077 from IODP/ICDP Expedition 364 provides unprecedented evidence for the physical processes in effect during the interaction of impact melt with rock-debris-laden seawater, following a large meteorite impact into waters of the Yucatán shelf. Evidence for this interaction is based on petrographic, microstructural and chemical exami...

Observational and logical arguments are presented for the lithology formerly named the Garson Member of the Onaping Formation being the clast‐bearing, fine‐grained, chilled Upper Contact Unit (UCU) of the Sudbury Igneous Complex (SIC) in the Garson region of the Sudbury impact structure. It differs considerably, however, from the UCU in the North R...

The 1.85 Ga Sudbury impact structure is considered a remnant of a peak-ring or multi-ring basin with an estimated original diameter of 150 to 200 km. The Offset Dikes are radial and concentric dikes around the Sudbury Igneous Complex (SIC) and are composed of the so-called inclusion-rich Quartz Diorite (IQD) and inclusion-poor Quartz Diorite (QD),...

The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological eve...

Highly expanded Cretaceous–Paleogene (K-Pg) boundary section from the Chicxulub peak ring, recovered by International Ocean Discovery Program (IODP)–International Continental Scientific Drilling Program (ICDP) Expedition 364, provides an unprecedented window into the immediate aftermath of the impact. Site M0077 includes ∼130 m of impact melt rock...

Porosity and its distribution in impact craters has an important effect on the petrophysical properties of impactites: seismic wave speeds and reflectivity, rock permeability, strength, and density. These properties are important for the identification of potential craters and the understanding of the process and consequences of cratering. The Chic...

Deformation is a ubiquitous process that occurs to rocks during impact cratering; thus, quantifying the deformation of those rocks can provide first‐order constraints on the process of impact cratering. Until now, specific quantification of the conditions of stress and strain within models of impact cratering has not been compared to structural obs...

Bolide impact is a ubiquitous geological process in the Solar System, which produced craters and basins filled with impact melt sheets on the terrestrial planets. However, it remains controversial whether these sheets were able to undergo large-scale igneous differentiation, or not. Here, we report on the discovery of large discrete bodies of melan...

Drill core petrography from the Rochechouart impact structure.

Deformation is a ubiquitous process that occurs to rocks during impact cratering; thus, quantifying the deformation of those rocks can provide first-order constraints on the process of impact cratering. Until now, specific quantification of the conditions of stress and strain within models of impact cratering has not been compared to structural obs...

In this Article, the middle initial of author Kosei E. Yamaguchi (of the IODP–ICDP Expedition 364 Science Party) was missing and his affiliation is to Toho University (not Tohu University). These errors have been corrected online.

Evidence for acoustic fluidization in the peak ring rocks of the Chicxulub impact structure.

Large meteorite impact structures on the terrestrial bodies of the Solar System contain pronounced topographic rings, which emerged from uplifted target (crustal) rocks within minutes of impact. To flow rapidly over large distances, these target rocks must have weakened drastically, but they subsequently regained sufficient strength to build and su...

IODP-Expedition 364 Chicxulub Peak Ring Drilling

First results from the Rochechouart impact crater drilling campaign.

Igneous rocks are the primary building blocks of planetary crusts. Most igneous rocks originate via decompression melting and/or wet melting of protolith lithologies within planetary interiors and their classification and compositional, petrographic, and textural characteristics, are well-studied. As our exploration of the Solar System continues, s...

The Offset Dykes are impact melt-bearing dykes related to the 1.85 Ga Sudbury impact structure. Currently, the dykes extend radially outward from—or occur concentrically around—the Sudbury Igneous Complex, which is the remnant of a differentiated impact melt sheet and the source of the dykes. The recently identified three Pele Offset Dykes intrude...

The current record of large-scale impact on Earth consists of close to 200 impact structures and some 30 impact events recorded in the stratigraphic record, only some of which are related to known structures. It is a preservation sample of a much larger production population, with the impact rate on Earth being higher than that of the moon. This is...

We use numerical modeling to investigate the combined effects of impact velocity and acoustic fluidization on lunar craters in the simple-to-complex transition regime. To investigate the full scope of the problem, we employed the two widely adopted Block-Model of acoustic fluidization scaling assumptions (scaling block size by impactor size and sca...

We use numerical modeling to investigate the combined effects of impact velocity and acoustic fluidization on lunar craters in the simple-to-complex transition regime. To investigate the full scope of the problem, we employed the two widely adopted Block-Model of acoustic fluidization scaling assumptions (scaling block size by impactor size and sca...

Large impact structures have complex morphologies, with zones of structural uplift that can be expressed topographically as central peaks and/or peak rings internal to the crater rim. The formation of these structures requires transient strength reduction in the target material and one of the proposed mechanisms to explain this behavior is acoustic...

The term “suevite” has been applied to various impact melt-bearing breccias found in different stratigraphic settings within terrestrial impact craters. Suevite was coined initially for impact glass-bearing breccias from the Ries impact structure, Germany, which is the type locality. Various working hypotheses have been proposed to account for the...

A new lithology identified in drill core from the Haughton impact structure shows textural evidence indicative of rapid cooling of a carbonate-silicate melt.

The 1.85 Ga Sudbury impact structure is one of the largest impact structures on Earth. Igneous bodies—the so-called “Basal Onaping Intrusion”—occur at the contact between the Sudbury Igneous Complex (SIC) and the overlying Onaping Formation and occupy ~50% of this contact zone. The Basal Onaping Intrusion is presently considered part of the Onaping...

For 50 years, the two Clearwater Lake impact structures in Québec have been considered as a typical crater doublet formed by the impact of a binary asteroid. New 40Ar/39Ar dating of melt rocks from the ≥36 km West Clearwater Lake (WCL) impact structure yielded two Early Permian plateau ages with a weighted mean age of 286.2 ± 2.2 (2.6) Ma (2σ; MSWD...

Here, we revisit the impactites of the West Clearwater Lake impact structure following a 2014 expedition; the first field study of this structure for 40 years.

Impacts were a major geologic process in early planetary evolution and served to physically characterize the early upper crusts and surfaces of planetary bodies. The impact flux of very large bodies was still sufficiently high, as late as ∼4.0 billion years ago, to produce impact basins with diameters measured in hundreds to thousands of kilometers...

Five large complex terrestrial impact structures were examined to determine the utility ofRADARSAT-l data to analyze these landforms. All impact structures studied were readily apparent in the RADARSAT-I data. In particular, the impact structures superimposed their own distinctive fracture patterns on the regional pattern, which results in the prod...

Textural similarities between surficial impact melt-bearing breccias from the Popigai and Ries impact structures reveal similar formation processes.

A semi-automated digital image analysis method is developed for the comparative textural study of impact melt-bearing breccias. This method uses the freeware software ImageJ developed by the National Institute of Health (NIH). Digital image analysis is performed on scans of hand samples (10–15 cm across), based on macroscopic interpretations of the...

Systematic mapping of the extent of Sudbury breccia in the North Range Footwall in collaboration with Wallbridge Mining Company Ltd. Preliminary results from small-scale mapping in summer 2012.

New insight into the nature and origin of the Garson Member of the Onaping Formation within the Sudbury impact structure in central Ontario, Canada.

In this study we investigated petrology and geochemistry of the Onaping Intrusion to further evaluate its origin and its relationship to the SIC.

A set of impact melt-bearing breccias from Popigai impact structure was analyzed using optical microscopy, scanning electron microscopy, electron microprobe and digital image analysis. Here, we present their petrographic and textural characterization.

The Offset Dykes at Sudbury are host to some of the largest Ni-Cu-PGE deposits in the world. This research focuses on understanding better their origin, the timing of emplacement, and how the different phases relate to one another.

The Sudbury Onaping Formation and the Ries suevite Ries have been postulated to form as the result of melt-fuel-coolant-interaction (MFCI), i.e., by the explosive interaction between impact melt and water. Both interpretations canot be correct.

Investigations of PDFs within the Onaping Intrusion suggest pressures of 20 to 25 GPa and preheated (630°C) or ambient temperatures during their formation.

The results of this study provide evidence that the Onaping Intrusion from the Sudbury impact structure is an impact melt and might be the roof rock of the SIC.

Macroscopic study of the diverse physical character of impact breccias. Intra- and inter-crater variability and its meaning in terms of geological processes.

[1] Geophysical data indicate that the 65.5 million years ago Chicxulub impact structure is a multi-ring basin, with three sets of semicontinuous, arcuate ring faults and a topographic peak ring (PR). Slump blocks define a terrace zone, which steps down from the inner rim into the annular trough. Fault blocks underlie the PR, which exhibits variabl...

A Mission Control Architecture is presented for a Robotic Lunar Sample Return Mission which builds upon the experience of the landed missions of the NASA Mars Exploration Program. This architecture consists of four separate processes working in parallel at Mission Control and achieving buy-in for plans sequentially instead of simultaneously from al...

Introduction Overview of craters Comparisons and implications Comparisons with lunar and Martian impact craters Concluding remarks References

Introduction Progenetic deposits Syngenetic deposits Epigenetic deposits Hydrocarbon accumulations Concluding remarks References

The 3.8 km in diameter Steinheim impact crater counts among the best-preserved complex impact structures with a central uplift on Earth. It lies within a sequence of flat-lying Triassic to Upper Jurassic sediments of the Swabian Alb plateau (SW Germany). Previous studies revealed the existence of silicate and carbonate melt lithologies within rocks...

On Horseshoe Island in Mistastin Lake there exist dikes of impact melt bearing breccia containing melt clasts. The composition of these clasts varies from the melt sheet indicating that there is a missing component contributing to the melt clasts.

Why Study Impact Craters?" is the title of a fundamental contribution by one of the pioneers of impact crater research, Eugene M. Shoemaker, in a landmark book in this field: Impact and Explosion Cratering (Roddy et al. 1977). In his far-reaching vision, Shoemaker wrote: "I submit that impact of solid bodies is the most fundamental of all processes...

Impact cratering is one of the most fundamental processes responsible for shaping the surfaces of solid planetary bodies. Even on Earth, where the impact record is sparse, it is now apparent that impact events also have played an important role throughout Earth's history, shaping the geological landscape, affecting the evolution of life and produci...

Impact cratering is one of the most fundamental processes responsible for shaping the surfaces of solid planetary bodies. One of the principal characteristics of impact events is the formation and emplacement of ejecta deposits, an understanding of which is critical for planetary exploration. Current models of ejecta emplacement, however, do not ac...

Peak rings are a feature of large impact craters on the terrestrial planets and are generally believed to be formed from deeply buried rocks that are uplifted during crater formation. The precise lithology and kinematics of peak ring formation, however, remains unclear. Previous work has revealed a suite of bright inward dipping reflectors beneath...

In support of future sample return missions, our team has successfully completed the first of three deployments in a lunar analogue mission to the South Pole Aitken Basin.

This study investigates the characteristics of impact melt-bearing breccias and impact melt rocks which occur as intrusive bodies in the central uplift of the Mistastin Lake impact structure.

Preliminary quantitative digital image analysis of `suevites' with minimal manual intervention. Parameters including modal abundances of `suevite' components were measured after particles of interest were segmented and analyzed using ImageJ software.

Shock metamorphic effects in samples from the Slate Islands, Lake Superior (48°40' N, 87°00' W) suggest that the islands are part of a meteorite impact structure. The islands form the central uplift of a complex crater and are ringed by a submerged trough and annular ridge with a diameter of 30 km. Precambrian bedrock units are locally brecciated a...

Quartz grains separated from the Cretaceous–Tertiary (K/T) boundary clay at Scollard Canyon, Alberta, have prominent, microscopic planar features. These occur in 15–30% of the grains from the lower 1.5 cm of the boundary clay. They commonly correspond to the ω and π orientations found at known meteorite impact sites and differ from deformation feat...

The sedimentary and volcanic formations of the Aillik series in the Makkovik Bay area of the Labrador coast are about 25 000 ft (~7620 m) in thickness. They have been folded into a series of northerly-trending folds and are intruded by gabbro, diorite, syenite, and abundant granite. Potassium–argon age determinations range from 1730 to 1830 million...

Coronas of orthopyroxene, amphibole and spinel, and occasional garnet occur between olivine and plagioclase in olivine gabbros and troctolites of the Hadlington gabbroic complex. Microprobe analyses show that changes in olivine composition are mirrored in the composition of the corona minerals. Textural evidence indicates that corona formation was...

A Mission Operations Design will be described for an analogue robotic sample return mission on the far side of the Moon in the South Pole-Aitken Basin. The analogous site will be within the Sudbury Impact Structure. This scenario will use a rover acting alone supported by a single relay spacecraft. The structure established and tested will offer le...

We compared the target types and the morphologies and morphometries of various features within fresh complex craters on Mars to assess target dependence. The wide scatter in depth-diameter data from Martian craters is more pronounced than for lunar or Mercurian craters. This was previously assumed to be predominantly due to significant degrees of d...

Chicxulub is the only known impact structure on Earth with a fully preserved peak ring, and it forms an important natural laboratory for the study of large impact structures and understanding of large-scale cratering on Earth and other planets. Seismic data collected in 1996 and 2005 reveal detailed images of the uppermost crater in the central bas...

Large-volume pseudotachylite bodies in impact structures are dike like and consist of angular and rounded wall-rock fragments enveloped by a microcrystalline and sporadically glassy matrix that crystallized from a melt. Knowledge of the formation of pseudotachylite bodies is important for understanding mechanics of complex crater formation. Most cu...

The Letters by Archibald et al. , Keller et al. , and Courtillot and Fluteau question our conclusion that the Cretaceous-Paleogene mass extinction was caused by the asteroid impact at Chicxulub. All three Letters stress that Deccan flood basalt volcanism played a major role in the extinction. Keller

Abstract– The 1.4–1.6 km thick Onaping Formation consists of a complex series of breccias and “melt bodies” lying above the Sudbury Igneous Complex (SIC) at the Sudbury impact structure. Based on the presence of shocked lithic clasts and various “glassy” phases, the Onaping has been described as a “suevitic” breccia, with an origin, at least in par...

“Suevites” are a poorly understood product of meteorite impacts. Here, we present new data on "suevites" from the Popigai structure. These impactites do not conform to the original definition of suevite (cf. "suevites" at the Ries and Rochechouart structures).

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...