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Jérôme Gattacceca Roger H. Hewins Jean‐Pierre Lorand Pierre Rochette France Lagroix Cécile Cournède Minoru Uehara Sylvain Pont Violaine Sautter Rosa. B. Scorzelli Chrystel Hombourger Pablo Munayco Brigitte Zanda Hasnaa Chennaoui Ludovic Ferrière 《Meteoritics & planetary science》2013,48(10):1919-1936
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The fourth Arab Impact Cratering and Astrogeology Conference (AICAC IV), April 9–12, 2017, Algiers (Algeria) 
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下载免费PDF全文 D. Belhaï H. Chennaoui‐Aoudjehane D. Baratoux L. Ferrière A. Lamali R. Sahoui P. Lambert A. Ayadi 《Meteoritics & planetary science》2017,52(9):2067-2071
We present a report about the fourth Arab Impact Cratering and Astrogeology Conference (AICAC IV) that took place in Algiers at the USTHB (Université des Sciences et Technologie Houari Boumedienne, Algiers, Algeria) in the presence of the presidents of the USTHB and Boumerdès Universities, the Director of CRAAG (Centre de Recherche en Astronomie, Astrophysique et Géophysique), and the General Director of the National Administration for Scientific Research (NASR/DGRSDT). This series of conferences aims to promote research interest for impact cratering in the Arab world and beyond, including for instance in African countries. In spite of persistently restraining travel measures to Algeria, the fourth edition held in Algiers was marked by continuous international participation, with participants from seven different countries. This conference focused on presentations of scientific results in the research fields related to planetology, meteorites, and impact craters. In particular, the Algerian impact structures were under the spotlights during both oral and poster sessions. During this conference, the presence of freshly graduated Ph.D. students and new Ph.D. projects related to impact cratering or meteoritic science was a positive sign for the consolidation of research groups in this domain in the Arab world and Africa. Therefore, international cooperation or external support and funding are still needed to ensure the development of this scientific discipline in this part of the world. 相似文献
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Hasnaa CHENNAOUI AOUDJEHANE Albert JAMBON Bruno REYNARD Philippe BLANC 《Meteoritics & planetary science》2005,40(7):967-979
Abstract— Silica in shergottites is a minor phase of great significance. Determining its structural state as either silica glass, quartz, cristobalite, tridymite, coesite, stishovite, or post‐stishovite could provide informations about their shock history. The purpose of this work is to assess the shock intensity in shergottites using two spectroscopic methods. On a conventional polished section, a scanning electron microscope (SEM) enables us to study the cathodoluminescence (CL) of silica at variable magnification. The results were crosschecked by systematic Raman spectroscopy of the selected areas. CL spectra differ substantially from one another and enable separating stishovite, high and low pressure silica glass, quartz, and cristobalite. We studied a set of five shergottites: Northwest Africa (NWA) 480, NWA 856, Zagami, Shergotty, and Los Angeles. Stishovite is common in Shergotty, Zagami, NWA 856, and NWA 480 and absent in the studied section of Los Angeles. High‐pressure glass is very common, particularly in close association with stishovite. According to the textural relationship, it may be a product of the retromorphosis (amorphization during decompression) of stishovite. Large stishovite areas result from the transformation of preexisting low‐pressure silica crystals, while needles result from the high‐pressure transformation of pyroxene to glass (melt) and silica. In the latter case, they are found in melt pockets and represent a small fraction of areas of overall pyroxene composition. Needles exhibit square sections of about 1 μm. Silica spots identical to those described previously as post‐stishovite are found in Shergotty, Zagami, NWA 480, and NWA 856. At present, the spectroscopic distinction of post‐stishovite from stishovite is difficult. Post‐stishovite is destroyed under the Raman beam, and CL spectra are possible mixtures of several phases (e.g., glass and post‐stishovite). It is concluded that the shock intensity is highly heterogeneous, and the pressure probably exceeded 60 GPa in all shergottites studied here. 相似文献
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A. Basu Sarbadhikari E. V. S. S. K. Babu T. Vijaya Kumar H. Chennaoui Aoudjehane 《Meteoritics & planetary science》2016,51(9):1588-1610
Tissint, a new unaltered piece of Martian volcanic materials, is the most silica‐poor and Mg‐Fe‐rich igneous rock among the “depleted” olivine‐phyric shergottites. Fe‐Mg zoning of olivine suggests equilibrium growth (<0.1 °C h?1) in the range of Fo80–56 and olivine overgrowth (Fo55–18) through a process of rapid disequilibrium (~1.0–5.0 °C h?1). The spatially extended (up to 600 μm) flat‐top Fe‐Mg profiles of olivine indicates that the early‐stage cooling rate of Tissint was slower than the other shergottites. The chemically metastable outer rim of olivine (55) consists of oscillatory phosphorus zoning at the impact‐induced melt domains and grew rapidly compared to the early to intermediate‐stage crystallization of the Tissint bulk. High‐Ca pyroxene to low‐Ca pyroxene and high‐Ca pyroxene to plagioclase ratios of Tissint are more comparable to the enriched basaltic and enriched olivine‐phyric shergottites. Dominance of augite over plagioclase induced augite to control the Ca‐buffer in the residual melt suppressing the plagioclase crystallization, which also caused a profound effect on the Al‐content in the late‐crystallized pyroxenes. Mineral chemical stability, phase‐assemblage saturation, and pressure–temperature path of evolution indicates that the parent magma entered the solidus and left the liquidus field at a depth of 40–80 km in the upper mantle. Petrogenesis of Tissint appears to be similar to LAR 06319, an enriched olivine‐phyric shergottite, during the early to intermediate stage of crystallization. A severe shock‐induced deformation resulted in remelting (10–15 vol%), recrystallization (most Fe‐rich phases), and exhumation of Tissint in a time scale of 1–8 yr. Tissint possesses some distinct characteristics, e.g., impact‐induced melting and deformation, forming phosphorus‐rich recrystallization rims of olivine, and shock‐induced melt domains without relative enrichment of LREEs compared to the bulk; and shared characteristics, e.g., modal composition and magmatic evolution with the enriched basaltic shergottites, evidently reflecting unique mantle source in comparison to the clan of the depleted members. 相似文献
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Harold C. Connolly Jr. Caroline Smith Gretchen Benedix Luigi Folco Kevin Righter Jutta Zipfel Akira Yamaguchi Hasnaa Chennaoui Aoudjehane 《Meteoritics & planetary science》2008,43(3):571-632
Abstract— In this edition of the Meteoritical Bulletin, 1443 approved meteorite names with their relevant data are reported, one from a specific location within Africa, 211 from Northwest Africa, 5 from KOREAMET, 598 from the Chinese Antarctic Expedition, 23 from the Americas, 151 from Asia, three from Australia, two from Europe, two from NOVA, and 447 from ANSMET that were not reported in the Meteoritical Bulletin no. 87. Also reported are 4 falls from the Americas. Some highlights of approved meteorites are 10 lunar (including NWA 5000, an 11.528 kg sample), 3 Martian, 4 irons (one from Indonesia), 2 ureilites, 5 mesosiderites, 1 pallasite, 6 brachinites, 3 CV3s, 4 CO3s, 8 CMs, 12 CK3s, and many more. Finally, the Committee on Nomenclature of the Meteoritical Society announces two new names series in North America. 相似文献