Imperial College London

Professor Gareth Collins

Faculty of EngineeringDepartment of Earth Science & Engineering

Professor of Planetary Science
 
 
 
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Contact

 

+44 (0)20 7594 1518g.collins Website

 
 
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Location

 

4.83Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

118 results found

Brooker LM, Balme MR, Conway SJ, Hagermann A, Barrett AM, Collins GS, Soare RJet al., 2018, Clastic polygonal networks around Lyot crater, Mars: Possible formation mechanisms from morphometric analysis, Icarus, Vol: 302, Pages: 386-406, ISSN: 0019-1035

© 2017 The Authors Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal forms have been observed on Mars leading to inferences about environmental conditions. We have identified clastic polygonal features located around Lyot crater, Mars (50°N, 30°E). These polygons are unusually large (>100 m diameter) compared to terrestrial clastic polygons, and contain very large clasts, some of which are up to 15 metres in diameter. The polygons are distributed in a wide arc around the eastern side of Lyot crater, at a consistent distance from the crater rim. Using high-resolution imaging data, we digitised these features to extract morphological information. These data are compared to existing terrestrial and Martian polygon data to look for similarities and differences and to inform hypotheses concerning possible formation mechanisms. Our results show the clastic polygons do not have any morphometric features that indicate they are similar to terrestrial sorted, clastic polygons formed by freeze-thaw processes. They are too large, do not show the expected variation in form with slope, and have clasts that do not scale in size with polygon diameter. However, the clastic networks are similar in network morphology to thermal contraction cracks, and there is a potential direct Martian analogue in a sub-type of thermal contraction polygons located in Utopia Planitia. Based upon our observations, we reject the hypothesis that polygons located around Lyot formed as freeze-thaw polygons and instead an alternative mechanism is put forward: they result from the infilling of earlier thermal contraction cracks by wind-blown mat

JOURNAL ARTICLE

Collins GS, Rae ASP, Morgan JV, Gulick Set al., 2018, THE FORMATION OF PEAK RINGS IN LARGE IMPACT CRATERS, 81st Annual Meeting of the Meteoritical-Society, Publisher: WILEY, Pages: 6215-6215, ISSN: 1086-9379

CONFERENCE PAPER

Derrick JG, LaJeunesse JW, Davison TM, Borg JP, Collins GSet al., 2018, Mesoscale simulations of shock compaction of a granular ceramic: effects of mesostructure and mixed-cell strength treatment, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, Vol: 26, ISSN: 0965-0393

JOURNAL ARTICLE

Derrick JG, Rutherford ME, Davison TM, Chapman DJ, Eakins DE, Collins GSet al., 2018, Interrogating heterogeneous compaction of analogue materials at the mesoscale through numerical modeling and experiments, ISSN: 0094-243X

© 2018 Author(s). Meteorites are classified by their relative exposure to three processes: aqueous alteration; thermal metamorphism; and shock processes. They constitute the main evidence available for the conditions in the early solar system. The precursor material to meteorites was bimodal and consisted of large spherical melt droplets (chondrules) surrounded by an extremely fine porous dust (matrix) with a high bulk porosity (> 50%). We present experiments and simulations, developed in tandem, investigating the heterogeneous compaction of matter analogous to these precursor materials. Experiments were performed at the European Synchrotron Radiation Facility (ESRF) where radiographs of the shock compaction and wave propagation were taken in-situ and in real time. Mesoscale simulations were performed using a shock physics code to investigate the heterogeneous response of these mixtures to shock loading. Two simple scenarios were considered in which the compacted material was pure matrix or pure matrix with a single inclusion. Good agreement was found between experiment and model in terms of shock position and relative compaction in the matrix. In addition, spatial variation in post-shock compaction was observed around the single inclusion despite uniform pre-shock porosity in the matrix. This shock-induced anisotropy in compaction could provide a new way of decoding the magnitude and direction by which a meteorite was shocked in the past.

CONFERENCE PAPER

Luther R, Zhu MH, Collins G, W√ľnnemann Ket al., 2018, Effect of target properties and impact velocity on ejection dynamics and ejecta deposition, Meteoritics and Planetary Science, Vol: 53, Pages: 1705-1732, ISSN: 1086-9379

© The Meteoritical Society, 2018. Impact craters are formed by the displacement and ejection of target material. Ejection angles and speeds during the excavation process depend on specific target properties. In order to quantify the influence of the constitutive properties of the target and impact velocity on ejection trajectories, we present the results of a systematic numerical parameter study. We have carried out a suite of numerical simulations of impact scenarios with different coefficients of friction (0.0–1.0), porosities (0–42%), and cohesions (0–150 MPa). Furthermore, simulations with varying pairs of impact velocity (1–20 km s−1) and projectile mass yielding craters of approximately equal volume are examined. We record ejection speed, ejection angle, and the mass of ejected material to determine parameters in scaling relationships, and to calculate the thickness of deposited ejecta by assuming analytical parabolic trajectories under Earth gravity. For the resulting deposits, we parameterize the thickness as a function of radial distance by a power law. We find that strength—that is, the coefficient of friction and target cohesion—has the strongest effect on the distribution of ejecta. In contrast, ejecta thickness as a function of distance is very similar for different target porosities and for varying impact velocities larger than ~6 km s−1. We compare the derived ejecta deposits with observations from natural craters and experiments.

JOURNAL ARTICLE

Collins GS, 2017, Moon formation: Punch combo or knock-out blow?, Nature Geoscience, Vol: 10, Pages: 72-73, ISSN: 1752-0894

JOURNAL ARTICLE

Collins GS, Lynch E, McAdam R, Davison TMet al., 2017, A numerical assessment of simple airblast models of impact airbursts, METEORITICS & PLANETARY SCIENCE, Vol: 52, Pages: 1542-1560, ISSN: 1086-9379

JOURNAL ARTICLE

Davison TM, Derrick JG, Collins GS, Bland PA, Rutherford ME, Chapman DJ, Eakins DEet al., 2017, Impact-induced compaction of primitive solar system solids: The need for mesoscale modelling and experiments, 14TH HYPERVELOCITY IMPACT SYMPOSIUM (HVIS 2017), Vol: 204, Pages: 405-412, ISSN: 1877-7058

JOURNAL ARTICLE

Forman LV, Bland PA, Timms NE, Daly L, Benedix GK, Trimby PW, Collins GS, Davison TMet al., 2017, Defining the mechanism for compaction of the CV chondrite parent body, GEOLOGY, Vol: 45, Pages: 559-562, ISSN: 0091-7613

JOURNAL ARTICLE

Holm-Alwmark S, Rae ASP, Ferriere L, Alwmark C, Collins GSet al., 2017, Combining shock barometry with numerical modeling: Insights into complex crater formation-The example of the Siljan impact structure (Sweden), METEORITICS & PLANETARY SCIENCE, Vol: 52, Pages: 2521-2549, ISSN: 1086-9379

JOURNAL ARTICLE

Jourdan F, Timms NE, Eroglu E, Mayers C, Frew A, Bland PA, Collins GS, Davison TM, Abe M, Yada Tet al., 2017, Collisional history of asteroid Itokawa, GEOLOGY, Vol: 45, Pages: 819-822, ISSN: 0091-7613

JOURNAL ARTICLE

Kring DA, Claeys P, Gulick SPS, Morgan JV, Collins GSet al., 2017, Chicxulub and the Exploration of Large Peak-Ring Impact Craters through Scientific Drilling, GSA Today, Vol: 27, Pages: 4-8, ISSN: 1052-5173

The Chicxulub crater is the only well-preserved peak-ring crater on Earth and linked, famously, to the K-T or K-Pg mass extinction event. For the first time, geologists have drilled into the peak ring of that crater in the International Ocean Discovery Program and International Continental Scientific Drilling Program (IODP-ICDP) Expedition 364. The Chicxulub impact event, the environmental calamity it produced, and the paleobiological consequences are among the most captivating topics being discussed in the geologic community. Here we focus attention on the geological processes that shaped the ~200-km-wide impact crater responsible for that discussion and the expedition’s first year results.

JOURNAL ARTICLE

Melosh HJ, Bland PA, Collins GS, Johnson BCet al., 2017, A SPECULATIVE "FIEFDOM" MODEL FOR CHONDRITE ORIGINS., 80th Annual Meeting of the Meteoritical-Society, Publisher: WILEY, Pages: A232-A232, ISSN: 1086-9379

CONFERENCE PAPER

Muxworthy AR, Bland PA, Davison TM, Moore J, Collins GS, Ciesla FJet al., 2017, Evidence for an impact-induced magnetic fabric in Allende, and exogenous alternatives to the core dynamo theory for Allende magnetization, METEORITICS & PLANETARY SCIENCE, Vol: 52, Pages: 2132-2146, ISSN: 1086-9379

JOURNAL ARTICLE

Rae ASP, Collins GS, Grieve RAF, Osinski GR, Morgan JVet al., 2017, Complex crater formation: Insights from combining observations of shock pressure distribution with numerical models at the West Clearwater Lake impact structure, METEORITICS & PLANETARY SCIENCE, Vol: 52, Pages: 1330-1350, ISSN: 1086-9379

JOURNAL ARTICLE

Rutherford ME, Chapman DJ, Derrick JG, Patten JRW, Bland PA, Rack A, Collins GS, Eakins DEet al., 2017, Probing the early stages of shock-induced chondritic meteorite formation at the mesoscale, SCIENTIFIC REPORTS, Vol: 7, ISSN: 2045-2322

JOURNAL ARTICLE

Smith R, 2017, Numerical modelling of tsunami generated by deformable submarine slides

Submarine slides can generate tsunami waves that cause significant damage and loss of life. Numerical modelling of submarine slide generated waves is complex and computationally challenging, but is useful to understand the nature of the waves that are generated, and identify the important factors in determining wave characteristics which in turn are used in risk assessments. In this work, the open-source, finite-element, unstructured mesh fluid dynamics framework Fluidity is used to simulate submarine slide tsunami using a number of different numerical approaches. First, three alternative approaches for simulating submarine slide acceleration, deformation and wave generation with full coupling between the slide and water in two dimensions are compared. Each approach is verified against benchmarks from experimental and other numerical studies, at different scales, for deformable submarine slides. There is good agreement to both laboratory results and other numerical models, both with a fixed mesh and a dynamically adaptive mesh, tracking important features of the slide geometry as the simulation progresses. Second, Fluidity is also used in a single-layer Bousinesq approximation in conjunction with a prescribed velocity boundary condition to model the propagation of slide tsunami in two and three dimensions. A new, efficient approach for submarine slide tsunami that accounts for slide dynamics and deformation is developed by imposing slide dynamics, derived from multi-material simulations. Two submarine slides are simulated in the Atlantic Ocean, and these generate waves up to 10 m high at the coast of the British Isles. Results indicate the largest waves are generated in the direction of slide motion. The lowest waves are generated perpendicular to the slide motion. The slide velocity and acceleration are the most important factors in determining wave height. Slides that deform generate higher waves than rigid slides, although this effect is of secondary importance f

THESIS DISSERTATION

Watters WA, Hundal CB, Radford A, Collins GS, Tornabene LLet al., 2017, Dependence of secondary crater characteristics on downrange distance: High-resolution morphometry and simulations, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 122, Pages: 1773-1800, ISSN: 2169-9097

JOURNAL ARTICLE

Baker DMH, Head JW, Collins GS, Potter RWKet al., 2016, The formation of peak-ring basins: Working hypotheses and path forward in using observations to constrain models of impact-basin formation, ICARUS, Vol: 273, Pages: 146-163, ISSN: 0019-1035

JOURNAL ARTICLE

Davison M, Collins GS, Bland PA, 2016, MESOSCALE MODELLING OF IMPACT COMPACTION OF PRIMITIVE SOLAR SYSTEM SOLIDS, 79th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A221-A221, ISSN: 1086-9379

CONFERENCE PAPER

Davison TM, Collins GS, Bland PA, 2016, MESOSCALE MODELING OF IMPACT COMPACTION OF PRIMITIVE SOLAR SYSTEM SOLIDS, ASTROPHYSICAL JOURNAL, Vol: 821, ISSN: 0004-637X

JOURNAL ARTICLE

Davison TM, Collins GS, Bland PA, Derrick JG, Ciesla FJet al., 2016, MESOSCALE MODELLING OF THE COMPACTION OF WATER-RICH ASTEROIDS BY LOW-VELOCITY IMPACTS, 79th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A222-A222, ISSN: 1086-9379

CONFERENCE PAPER

Derrick JG, Rutherford ME, Davison TM, Eakins DE, Collins GSet al., 2016, INTERROGATING HETEROGENEOUS COMPACTION OF METEORITIC MATERIAL AT THE MESOSCALE USING ANALOG EXPERIMENTS AND NUMERICAL MODELS, 79th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A228-A228, ISSN: 1086-9379

CONFERENCE PAPER

Forman LV, Bland PA, Timms NE, Collins GS, Davison TM, Ciesla FJ, Benedix GK, Daly L, Trimby PW, Yang L, Ringer SPet al., 2016, Hidden secrets of deformation: Impact-induced compaction within a CV chondrite, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 452, Pages: 133-145, ISSN: 0012-821X

JOURNAL ARTICLE

Johnson BC, Blair DM, Collins GS, Melosh HJ, Freed AM, Taylor GJ, Head JW, Wieczorek MA, Andrews-Hanna JC, Nimmo F, Keane JT, Miljkovic K, Soderblom JM, Zuber MTet al., 2016, Formation of the Orientale lunar multiring basin, SCIENCE, Vol: 354, Pages: 441-444, ISSN: 0036-8075

JOURNAL ARTICLE

Johnson BC, Collins GS, Minton DA, Bowling TJ, Simonson BM, Zuber MTet al., 2016, Spherule layers, crater scaling laws, and the population of ancient terrestrial impactors, ICARUS, Vol: 271, Pages: 350-359, ISSN: 0019-1035

JOURNAL ARTICLE

Kring DA, Kramer GY, Collins GS, Potter RWK, Chandnani Met al., 2016, Peak-ring structure and kinematics from a multi-disciplinary study of the Schrodinger impact basin, NATURE COMMUNICATIONS, Vol: 7, ISSN: 2041-1723

JOURNAL ARTICLE

Lyons RJ, Ciesla FJ, Bowling TJ, Davison TM, Collins GSet al., 2016, THE EFFECT OF EARLY IMPACTS ON IRON METEORITE COOLING RATES, 79th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A433-A433, ISSN: 1086-9379

CONFERENCE PAPER

Miljkovic K, Collins GS, Wieczorek MA, Johnson BC, Soderblom JM, Neumann GA, Zuber MTet al., 2016, Subsurface morphology and scaling of lunar impact basins, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 121, Pages: 1695-1712, ISSN: 2169-9097

JOURNAL ARTICLE

Monteux J, Collins GS, Tobie G, Choblet Get al., 2016, Consequences of large impacts on Enceladus' core shape, ICARUS, Vol: 264, Pages: 300-310, ISSN: 0019-1035

JOURNAL ARTICLE

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