scholarly journals Characterization of shocked quartz grains from Chicxulub peak ring granites and shock pressure estimates

2020 ◽  
Vol 55 (10) ◽  
pp. 2206-2223
Author(s):  
Jean‐Guillaume Feignon ◽  
Ludovic FerriÈre ◽  
Hugues Leroux ◽  
Christian Koeberl
Keyword(s):  
Shock Pressure ◽  
Shocked Quartz ◽  
Quartz Grains

Shocked quartz grains from the Målingen structure, Sweden-Evidence for a twin crater of the Lockne impact structure

2014 ◽  
Vol 49 (6) ◽  
pp. 1076-1082 ◽  
Author(s):  
C. Alwmark ◽  
S. Alwmark-Holm ◽  
J. Ormö ◽  
E. Sturkell
Keyword(s):  
Impact Structure ◽  
Shocked Quartz ◽  
Quartz Grains

Application de l'exoscopie des quartz à quelques échantillons prélevés en Manche orientale

1975 ◽  
Vol 279 (1288) ◽  
pp. 279-288 ◽  
Keyword(s):  
Eastern Area ◽  
History Of ◽  
Simultaneous Study ◽  
Binocular Microscope ◽  
Principal Value ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Advanced Development ◽  
Quartz Grains

The morphology and the appearance of quartz grains reveal the history of their movement and sedimentation. Consequently, many researchers have tried to decipher geological ‘memory’ using binocular microscopes and transmission and scanning electron-microscopes. Krinsley and his colleagues, most notably, have consequently been able to define some superficial characteristics of quartz grains from glacial, fluvo-glacial, littoral and aeolian regions. Thanks to the work of Cailleux (1942) and Cailleux & Trichard (1959) on morphoscopy, we now know that a binocular microscope allows us to recognize in most cases a marine or fluvo-glacial sand which has been subjected to wind or water transport. The present author believes that in this work, the principal value of the electron scanning microscope, thanks to the powerful magnifications that it allows, would be to determine the characterization of incipient modification on very slightly modified quartz grains and not those of advanced development visible with low magnification. It is not possible to study separately mechanical and chemical effects; however, the simultaneous study of these, of their causes and of their interactions, in different surroundings has enabled the author to draw up an atlas of the surface aspects presented by quartz grains at various stages of pedological evolution and to characterize fluviatile, inter-tidal, infra-tidal and wind-eroded features of differing intensity, even when these are only slightly marked on the grains. One of the first applications of this method here called exoscopy was undertaken on quartz samples from cores taken in the eastern area of the English Channel by the ‘Terebel’. Exoscopy and endoscopy (G. Deicha and colleagues) permit the reconstruction of a large part of the geological history of detrital quartzes by going back, step by step, to the original formation.

scholarly journals Characterization of amorphous material in shocked quartz by NMR spectroscopy

1994 ◽  
Author(s):  
R. A. Assink ◽  
M. B. Boslough ◽  
R. T. Cygan
Keyword(s):  
Nmr Spectroscopy ◽  
Amorphous Material ◽  
Shocked Quartz

Microscopic planar features in quartz from Scollard Canyon, Alberta, and the Cretaceous–Tertiary boundary event

1988 ◽  
Vol 25 (9) ◽  
pp. 1530-1534 ◽  
Author(s):  
R. A. F. Grieve ◽  
J. Alexopoulos
Keyword(s):  
Continental Margin ◽  
Crystalline Rocks ◽  
Meteorite Impact ◽  
Isotopic Data ◽  
Near Surface ◽  
Deformation Features ◽  
Shocked Quartz ◽  
Quartz Grains ◽  
Geologic Processes ◽  
Basaltic Material

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 features produced by other dynamic geologic processes. Basal planar features, however, are absent here and at other K/T sites. One possible explanation is that quartz at boundary sites is an incomplete sample of shocked quartz from the postulated K/T impact and unshocked detrital quartz. The source of the shocked quartz most likely was close to the point of impact and near surface. This and previous isotopic data suggest the K/T target site contained a relatively thin upper unit of quartz-bearing crystalline rocks overlying basaltic material, corresponding possibly to thinned continent or a continental margin.

scholarly journals Caracterisation Sedimentologique Et Mineralogique Des Formations Tertiares Du Bassin Onshore De La Region D’abidjan, Cote d’Ivoire

2018 ◽  
Vol 14 (18) ◽  
pp. 218
Author(s):  
Jean Claude N’zi ◽  
Mamadou Toure ◽  
N’goran Jean-Paul Yao ◽  
Rachelle Affouet Kouassi ◽  
Zeli Bruno Digbehi ◽  
...  
Keyword(s):  
Aquatic Environment ◽  
Sedimentary Basin ◽  
Point Of View ◽  
Hydrodynamic Conditions ◽  
Calcium Carbonates ◽  
Shallow Marine ◽  
South West ◽  
Quartz Grains

Analyzes carried out on 262 cuttings samples from two boreholes located in the coastal sedimentary basin of Abidjan (south-west of the lagoon fault) were aimed at the paleoenvironmental determination of tertiary-age deposits. Indeed, these sedimentological analyses allowed the characterization of the lithological nature of the formations encountered by AB and BM drilling. They also helped to determine the origin of the sedimented material as well as the hydrodynamic conditions that governed the placement of the various deposits. Moreover, the deposits medium of the studied formations was revealed. The formations consist of an alternation of sands and sandy clays in the AB drilling and essentially glauconous clays for BM drilling. In the clay intervals, there is a weak presence of calcium carbonates on the whole of the two boreholes. The sands analyzed are of different granulometric grades (very coarse, coarse, medium and fine) according to the intervals. This, therefore, shows the different variations in the energy of the current that transported the sediment. From a facies point of view, the granulometric facies is dominant in the study area, indicating the variation in watercourse competence during sedimentation. Mostly sub-angular to sub-rounded quartz grains suggest a relatively distal proving source while their shiny blunted appearance evokes an aquatic environment. The sediments of these wells are therefore sands of fluviatile origin, deposited in a shallow marine environment.

A search for shocked quartz grains and impact ejecta in early Silurian sediments on Gotland, Sweden

1994 ◽  
Vol 131 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Birger Schmitz ◽  
Lennart Jeppsson ◽  
Johan Ekvall
Keyword(s):  
Lateral Spreading ◽  
Asteroid Impact ◽  
The Earth ◽  
Planar Shock ◽  
Impact Ejecta ◽  
Single Grain ◽  
Shocked Quartz ◽  
Impact Events ◽  
Impact Origin ◽  
Quartz Grains

AbstractAll bentonite and bentonite-resembling layers thicker than a few millimetres from a 120m-thick Early Silurian sequence on Gotland, Sweden, were searched for shocked quartz grains of comet or asteroid impact origin. Although more than 200000 quartz grains from 86 bentonite samples were studied, not one single grain with multiple planar shock features was found. The studied sequence represents sedimentation during a period of about 2 million years. Impact frequencies, estimated from the cratering record and astronomical observations, indicate that during a 2-myr- period on average 20 comet or asteroid bodies larger than 0.5 km in diameter strike the Earth. The number of smaller impacting bodies is many times higher. In the light of this high frequency of impacts, the absence of any shocked-quartz-bearing fallout layer in our sequence indicates that lateral spreading of such ejecta is relatively restricted during small- and medium-scale impact events.The results also show that shocked quartz in general is absent or extremely rare in volcanic ash. This strengthens the case for an impact-related origin of shocked quartz grains in the Cretaceous–Tertiary boundary days.

Shocked quartz grains at the Cretaceous-Tertiary boundary

1988 ◽  
Vol 75 (6) ◽  
pp. 307-308 ◽  
Author(s):  
R. Seitz ◽  
B. F. Bohor
Keyword(s):  
Shocked Quartz ◽  
Quartz Grains

Characterization of exogenic fulgurites from an archaeological site in Tiedra, Valladolid, Spain

2019 ◽  
Vol 156 (08) ◽  
pp. 1455-1462
Author(s):  
Pablo Martín-Ramos ◽  
Francisco PSC Gil ◽  
Francisco J Martín-Gil ◽  
Jesús Martín-Gil
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fluorescence Spectroscopy ◽  
Iron Oxides ◽  
Archaeological Site ◽  
X Ray ◽  
Shocked Quartz ◽  
Type V

AbstractStudies on type-V fulgurites are very sparse in the literature. This work reports on the characterization of natural exogenic fulgurites found at the archaeological site of Cerro de la Ermita (Tiedra, Valladolid, Spain), which was firstly a Celtiberian and then a Roman locum sacrum. Data from X-ray powder diffraction, X-ray fluorescence spectroscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy suggest that the fulgurites consist of naquite, piroxenes, iron oxides, shocked quartz and neo-formed cristobalite.

Characterization of magnetite particles in shocked quartz by means of electron- and magnetic force microscopy: Vredefort, South Africa

1999 ◽  
Vol 137 (3) ◽  
pp. 232-245 ◽  
Author(s):  
Marthinus Cloete ◽  
Rodger J. Hart ◽  
Herbert K. Schmid ◽  
Martyn Drury ◽  
Chris M. Demanet ◽  
...  
Keyword(s):  
South Africa ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Force Microscopy ◽  
Magnetite Particles ◽  
Shocked Quartz
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