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Michael H Poelchau - One of the best experts on this subject based on the ideXlab platform.
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stress strain evolution during peak ring formation a case study of the chicxulub impact structure
Journal of Geophysical Research, 2019Co-Authors: Ulrich Riller, Richard A F Grieve, Michael H Poelchau, G S Collins, G R Osinski, A S P Rae, T M Davison, J V Morgan, Iodpicdp Expedition ScientistsAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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Stress‐Strain Evolution During Peak‐Ring Formation: A Case Study of the Chicxulub Impact Structure
Journal of Geophysical Research. Planets, 2019Co-Authors: Auriol Rae, Ulrich Riller, Michael H Poelchau, Gareth Collins, Thomas Davison, Richard Grieve, Gordon Osinski, Joanna Morgan, S. P. S. Gulick, Elise ChenotAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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Rock fluidization during peak-ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Auriol S. P. Rae, Felix M. Schulte, Joanna V. Morgan, Gareth S. Collins, Sean P.s. Gulick, Richard A F Grieve, Michael H Poelchau, H. J. Melosh, Johanna LofiAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.Catastrophic rock weakening upon impact of a meteorite, and hence flow, is shown to be followed by regained rock strength that enabled the formation of the peak ring during Cratering.
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rock fluidization during peak ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Felix M. Schulte, Sean P.s. Gulick, Johanna Lofi, Richard A F Grieve, Michael H Poelchau, G S Collins, Jay H Melosh, J V Morgan, Abdoulaye DiawAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.
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the memin research unit scaling impact Cratering experiments in porous sandstones
Meteoritics & Planetary Science, 2013Co-Authors: Michael H Poelchau, T Kenkmann, Klaus Thoma, Tobias Hoerth, Anja Dufresne, F SchaferAbstract:– The MEMIN research unit (Multidisciplinary Experimental and Modeling Impact research Network) is focused on analyzing experimental impact craters and experimental Cratering processes in geological materials. MEMIN is interested in understanding how porosity and pore space saturation influence the Cratering process. Here, we present results of a series of impact experiments into porous wet and dry sandstone targets. Steel, iron meteorite, and aluminum projectiles ranging in size from 2.5 to 12 mm were accelerated to velocities of 2.5–7.8 km s−1, yielding craters with diameters between 3.9 and 40 cm. Results show that the target’s porosity reduces crater volumes and Cratering efficiency relative to nonporous rocks. Saturation of pore space with water to 50% and 90% increasingly counteracts the effects of porosity, leading to larger but flatter craters. Spallation becomes more dominant in larger-scale experiments and leads to an increase in Cratering efficiency with increasing projectile size for constant impact velocities. The volume of spalled material is estimated using parabolic fits to the crater morphology, yielding approximations of the transient crater volume. For impacts at the same velocity these transient craters show a constant Cratering efficiency that is not affected by projectile size.
Richard A F Grieve - One of the best experts on this subject based on the ideXlab platform.
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stress strain evolution during peak ring formation a case study of the chicxulub impact structure
Journal of Geophysical Research, 2019Co-Authors: Ulrich Riller, Richard A F Grieve, Michael H Poelchau, G S Collins, G R Osinski, A S P Rae, T M Davison, J V Morgan, Iodpicdp Expedition ScientistsAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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Rock fluidization during peak-ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Auriol S. P. Rae, Felix M. Schulte, Joanna V. Morgan, Gareth S. Collins, Sean P.s. Gulick, Richard A F Grieve, Michael H Poelchau, H. J. Melosh, Johanna LofiAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.Catastrophic rock weakening upon impact of a meteorite, and hence flow, is shown to be followed by regained rock strength that enabled the formation of the peak ring during Cratering.
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rock fluidization during peak ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Felix M. Schulte, Sean P.s. Gulick, Johanna Lofi, Richard A F Grieve, Michael H Poelchau, G S Collins, Jay H Melosh, J V Morgan, Abdoulaye DiawAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.
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Cratering history and lunar chronology
Reviews in Mineralogy & Geochemistry, 2006Co-Authors: D Stoffler, B A Ivanov, G Ryder, Natalia Artemieva, Mark J Cintala, Richard A F GrieveAbstract:The Moon is exceptional and important because it is the only planetary body besides the Earth for which we have both a detailed stratigraphic history and datable rock samples that can be related to specific geomorphologic units (Fig. 5.1⇓). The Moon has preserved much of its magmatic and impact record of at least the last 4 billion years. While its endogenic history is of great interest for the fundamentals of planetary interiors and surfaces, the Moon has become a calibration plate for the Cratering record of the Earth-Moon system, and by extrapolation, of the entire inner solar system if one assumes a heliocentric origin for impactor populations. These populations range from asteroids through long and short period comets to interplanetary dust, and cover a size range from hundreds of kilometers to micrometers. Figure 5.1. Telescopic view of the nearside of the Earth’s Moon with landing sites of the Apollo and Luna missions. This chapter reviews the presently available data sets in support of this paradigmatic assumption, as follows: (1) the phenomenology of lunar impact craters, (2) the terrestrial record of the impact Cratering process and the interpretation of terrestrial impactites as far as this “ground truth” is relevant for the interpretation of lunar impact craters and datable lunar impact breccias and melt rocks, (3) the theory and numerical simulation of the Cratering process and the characteristics of the Earth-Moon crossing population of impactors (asteroids and comets), (4) the principles of relative age dating of lunar surface units and the general lunar stratigraphy, (5) the stratigraphic significance and ages of lunar samples (impactites and basalts) and, based on this data set, the absolute ages of lunar surface units, (6) the Cratering rate of the Moon as a function of time, and (7) the time calibration of this Cratering rate based on the …
Ulrich Riller - One of the best experts on this subject based on the ideXlab platform.
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stress strain evolution during peak ring formation a case study of the chicxulub impact structure
Journal of Geophysical Research, 2019Co-Authors: Ulrich Riller, Richard A F Grieve, Michael H Poelchau, G S Collins, G R Osinski, A S P Rae, T M Davison, J V Morgan, Iodpicdp Expedition ScientistsAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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Stress‐Strain Evolution During Peak‐Ring Formation: A Case Study of the Chicxulub Impact Structure
Journal of Geophysical Research. Planets, 2019Co-Authors: Auriol Rae, Ulrich Riller, Michael H Poelchau, Gareth Collins, Thomas Davison, Richard Grieve, Gordon Osinski, Joanna Morgan, S. P. S. Gulick, Elise ChenotAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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Rock fluidization during peak-ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Auriol S. P. Rae, Felix M. Schulte, Joanna V. Morgan, Gareth S. Collins, Sean P.s. Gulick, Richard A F Grieve, Michael H Poelchau, H. J. Melosh, Johanna LofiAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.Catastrophic rock weakening upon impact of a meteorite, and hence flow, is shown to be followed by regained rock strength that enabled the formation of the peak ring during Cratering.
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rock fluidization during peak ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Felix M. Schulte, Sean P.s. Gulick, Johanna Lofi, Richard A F Grieve, Michael H Poelchau, G S Collins, Jay H Melosh, J V Morgan, Abdoulaye DiawAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.
G S Collins - One of the best experts on this subject based on the ideXlab platform.
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stress strain evolution during peak ring formation a case study of the chicxulub impact structure
Journal of Geophysical Research, 2019Co-Authors: Ulrich Riller, Richard A F Grieve, Michael H Poelchau, G S Collins, G R Osinski, A S P Rae, T M Davison, J V Morgan, Iodpicdp Expedition ScientistsAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.
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rock fluidization during peak ring formation of large impact structures
Nature, 2018Co-Authors: Ulrich Riller, Felix M. Schulte, Sean P.s. Gulick, Johanna Lofi, Richard A F Grieve, Michael H Poelchau, G S Collins, Jay H Melosh, J V Morgan, Abdoulaye DiawAbstract: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 sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during Cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during Cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial Cratering, followed by increasingly localized faulting.
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the impact Cratering process
Elements, 2012Co-Authors: G S Collins, Jay H Melosh, G R OsinskiAbstract:Impact Cratering is an important and unique geologic process. The high speeds, forces and temperatures involved are quite unlike conventional endogenic processes, and the environmental consequences can be catastrophic. Kilometre-scale craters are excavated and collapse in minutes, in some cases distributing debris around the globe and exhuming deeply buried strata. In the process, rocks are deformed, broken, heated and transformed in unique ways. Elevated temperatures in the crust may persist for millennia, and important chemical reactions are promoted by the extreme environment of the impact plume. Released gases may cause long-term perturbations to the climate, and impact-related phosphorus reduction may have played a role in the origin of life on Earth.
A S P Rae - One of the best experts on this subject based on the ideXlab platform.
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stress strain evolution during peak ring formation a case study of the chicxulub impact structure
Journal of Geophysical Research, 2019Co-Authors: Ulrich Riller, Richard A F Grieve, Michael H Poelchau, G S Collins, G R Osinski, A S P Rae, T M Davison, J V Morgan, Iodpicdp Expedition ScientistsAbstract: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 observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak‐ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of Cratering; and (3) the orientation and magnitude of principal stresses during each stage of Cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions.