Impact melting in sedimentary target rocks: An assessment

Osinski, G. R.; Spray, John G.; Grieve, R. A. F.

doi:10.1130/2008.2437(01)

Cited by 45 publications

(177 citation statements)

References 54 publications

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“…However, more recent work suggests that impact melting is more common in sedimentary targets than has, hitherto, been believed and that impact melt rocks are produced ( Fig. 1.10f; Osinski et al, 2008b). These observations are generally consistent with numerical modelling studies (Wünnemann et al, 2008), which also suggests that the volume of melt produced by impacts into dry porous sedimentary rocks should be greater than that produced by impacts in a crystalline target.…”

Section: Recognition Of Impact Craterssupporting

confidence: 78%

Impact Cratering: Processes and Products

2012

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Section: Recognition Of Impact Craterssupporting

confidence: 78%

Impact Cratering: Processes and Products

2012

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“…This is a difficult and unsolved problem and one that has gotten relatively little attention thus far [42]. However, Boehm lamellae in the quartz grains signify a high-stress regime, indicating a probable metamorphic origin, while PDFs indicates shock metamorphism via impact.…”

Section: Discussionmentioning

confidence: 99%

“…One of the unusual shock effects is shock lithification and production of instant rock, whereby unconsolidated quartz sands are compacted into coherent sandstone like lithologies [42]. We urge that further field work must be carried out in the study area and the surrounding areas to expose the site of the source impact crater, which might lie undiscovered somewhere in Sinai.…”

Section: Discussionmentioning

confidence: 99%

Microspherules-Bearing White Sandstone: Implication of Cosmic Impact Event near Jurassic-Cretaceous Boundary in West Central Sinai, Egypt

Badawy¹,

Zayed²,

Shahien³

2016

GEP

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The presence of glass microspherules enclosing relict grains, shattered quartz and silicon carbide in white sandstone beds near the Jurassic-Cretaceous boundary in west central Sinai indicates a cosmic impact event. Characterization of the impact microspherules and proposing a reasonable scenario for their origin are the aims of this work. Field observations, optical, binocular, scanning electron and high-resolution transmitted electron microscopy investigations and chemical analyses were carried out. The study revealed that glass microspherules have high Al2O3 and FeO contents and low CaO and MgO contents. The high content of Al2O3 indicates that the source of microtektite-like microspherules is attributed to the melting of a clay-rich sandstone and carbonaceous matter, while the high content of FeO indicates admixing with projectile matter. The reaction between silica and carbon was carried out under conditions of high temperature (T > 1000˚C) and carbon (C/Si > 1) which resulted in the production of silicon carbide with microdiamond intergrowth. Consequently, this intergrowth is in accordance with the impact origin via rapid condensation and growth within a vapor phase. In spite of the fact that no source crater has been recognized to date in the study area, the authors propose at least a single cosmic impact event scenario for the recorded glass microspherules in west central Sinai. The impact excavated the Paleozoic siliciclastic sedimentary rocks and then the glass microspherules showered the area of study. The deposition of microtektite-like glass particles within the white sandstone beds of the Malha Formation took place in the fluvial plain terrestrial environment. This setting precluded severe post-depositional reworking, yielding preservation of the glass particles in a primary layer. Eventually, lateral migration of the braided channels led to the reworking of the microspherules layer and the spatial dispersal of the shattered quartz. H. S. Badawy et al.54

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“…More generally, the role of melting and devolatilization has been discussed and debated by Osinski et al (2008), Hörz et al (2015), and Bell (2016). Howard (2011) invoked volatiles in the shallow crust to enhance the dispersal of impact melts as tektites.…”

Section: Related Resourcesmentioning

confidence: 99%