Editorial     

John Leibacher  Takashi Sakurai  Lidia van Driel-Gesztelyi 《Solar physics》2005,229(1):3

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Geodynamic setting of gold deposits in Eastern and Central Trans-Baikal (Chita Region, Russia)   总被引：1，自引：0，他引：1  

Yu. A. Zorin  Lidia D. Zorina  A. M. Spiridonov  I. G. Rutshtein 《Ore Geology Reviews》2001,17(4):1102

It is proposed that there are three types of gold deposits in Eastern and Central Transbaikalia (Trans-Baikal province), namely: (i) high-sulphide intrusion-related deposits with some signs of porphyry deposits, (ii) low-sulphide intrusion-related deposits, and (iii) low-sulphide epithermal Au–Ag deposits. Most of the gold deposits belong to the first two types, and their ages are Middle–Late Jurassic. Deposits of the third type are not numerous, and their age is Early Cretaceous.The majority of the gold mineralization is spatially related to the two branches of the Mongolia–Okhotsk suture, along which Siberia collided, at the Early/Middle Jurassic boundary, with the Mongolia–North China continent and the Onon island-arc terrane located between the two continents. Collision-related thrusting, folding and magmatism lasted until the latest Jurassic, when they gave way to post-collisional rifting that continued until the end of Early Cretaceous.According to their age, relation to magmatism and tectonic framework, the intrusion-related deposits (high- and low-sulphide) were formed in a regional collisional setting. Extensional environments at that time existed only in local areas in the roofs of great magmatic chambers. Low-sulphide epithermal deposits were formed during Early Cretaceous post-collisional rifting.  相似文献   

Václav Bumba (1925 – 2018)     

Pavel Kotrč  Petr Heinzel  Michal Sobotka  Pavel Ambrož  Lidia van Driel-Gesztelyi 《Solar physics》2018,293(3):40

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Partial amorphization of experimentally shocked plagioclase: A spectroscopic study     

Lidia Pittarello  Joerg Fritz  Julia Roszjar  Christoph Lenz  Chutimun Chanmuang N.  Christian Koeberl 《Meteoritics & planetary science》2020,55(3):669-678

Shock amorphization of plagioclase, from partial to complete, has been used to evaluate the degree of shock in meteorites. Important information on the shock amplitude can be derived from the measurement of the refractive index in plagioclase, either from mineral separates or in petrographic thin sections. However, this technique is time‐consuming, and associated sample preparations are considered destructive and are not always possible for precious and rare meteorite samples. In addition, plagioclase amorphization is commonly inhomogeneous at the sample scale and a statistically meaningful number of grains must be considered. Here, we apply several nondestructive spectroscopic techniques, such as Raman spectroscopy, photoluminescence, and cathodoluminescence, to plagioclase experimentally shocked at 28 GPa, and thus in the transition regime between crystalline plagioclase and fully amorphous material. Most of the plagioclase was transformed into diaplectic glass at 28 GPa, yet some grains exhibit heterogeneously distributed crystalline domains. This confirms that intrinsic and extrinsic factors lead to local variations in the intensity of the shock pressure within individual plagioclase crystals of homogeneous composition. The amorphization of plagioclase can qualitatively (and potentially also quantitatively) be investigated by spectroscopic techniques, highlighting such local variations in the shock efficiency.  相似文献   

Shock metamorphism in plagioclase and selective amorphization     

Lidia Pittarello  Luke Daly  Annemarie E. PickersgilL  Ludovic Ferrire  Martin R. Lee 《Meteoritics & planetary science》2020,55(5):1103-1115

Plagioclase feldspar is one of the most common rock‐forming minerals on the surfaces of the Earth and other terrestrial planetary bodies, where it has been exposed to the ubiquitous process of hypervelocity impact. However, the response of plagioclase to shock metamorphism remains poorly understood. In particular, constraining the initiation and progression of shock‐induced amorphization in plagioclase (i.e., conversion to diaplectic glass) would improve our knowledge of how shock progressively deforms plagioclase. In turn, this information would enable plagioclase to be used to evaluate the shock stage of meteorites and terrestrial impactites, whenever they lack traditionally used shock indicator minerals, such as olivine and quartz. Here, we report on an electron backscatter diffraction (EBSD) study of shocked plagioclase grains in a metagranite shatter cone from the central uplift of the Manicouagan impact structure, Canada. Our study suggests that, in plagioclase, shock amorphization is initially localized either within pre‐existing twins or along lamellae, with similar characteristics to planar deformation features (PDFs) but that resemble twins in their periodicity. These lamellae likely represent specific crystallographic planes that undergo preferential structural failure under shock conditions. The orientation of preexisting twin sets that are preferentially amorphized and that of amorphous lamellae is likely favorable with respect to scattering of the local shock wave and corresponds to the “weakest” orientation for a specific shock pressure value. This observation supports a universal formation mechanism for PDFs in silicate minerals.  相似文献   

Editorial Appreciation     

John Leibacher  Takashi Sakurai  Lidia van Driel-Gesztelyi 《Solar physics》2010,262(1):1-2

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Melting and cataclastic features in shatter cones in basalt from the Vista Alegre impact structure,Brazil          下载免费PDF全文

Lidia Pittarello  Fabrizio Nestola  Cecilia Viti  Alvaro Penteado Crósta  Christian Koeberl 《Meteoritics & planetary science》2015,50(7):1228-1243

Shatter cones are one of the most widely recognized pieces of evidence for meteorite impact events on Earth, but the process responsible for their formation is still debated. Evidence of melting on shatter cone surfaces has been rarely reported in the literature from terrestrial impact craters but has been recently observed in impact experiments. Although several models for shatter cones formation have been proposed, so far, no one can explain all the observed features. Shatter cones' from the Vista Alegre impact structure, Brazil, formed in fine‐grained basalt of the Jurassic‐Cretaceous Serra Geral Formation (Paraná large igneous province). A continuous quenched melt film, consisting of a crystalline phase, mica, and amorphous material, decorates the striated surface. Ultracataclasites, containing subrounded pyroxene clasts in an ultrafine‐grained matrix, occur subparallel to the striated surface. Several techniques were applied to characterize the crystalline phase in the melt, including Raman spectroscopy and transmission electron microscopy. Results are not consistent with any known mineral, but they do suggest a possible rare or new type of clinopyroxene. This peculiar evidence of melting and cataclasis in relation with shatter cone surfaces is interpreted as the result of tensile fracturing at the tip of a fast propagating shock‐induced rupture, which led to the formation of shatter cones at the tail of the shock front, likely during the early stage of the impact events.  相似文献   

Preface: Probing the Sun Inside and Out     

Louise Harra  Deborah Baker  Rachel Howe  John Leibacher  Lidia van Driel-Gesztelyi 《Solar physics》2015,290(11):3091-3094

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An integrated approach to environmental quality assessment in a coastal setting in Campania (Southern Italy)   总被引：1，自引：1，他引：0  

Rosa Verde  Marco Vigliotti  Lidia Prevedello  Mario Sprovieri  Daniela Ruberti 《Environmental Earth Sciences》2013,70(1):407-424

The coastal region of Southern Italy’s Caserta province, known as the Litorale Domitio (Domitia coast) has been subjected to increasing pressure from unsustainably fast economic and urban growth in the last century, that resulted in a induced serious land degradation. To obtain a comprehensive picture of the ecological status of the Domitia coastal zone (Campania, Southern Italy), a holistic methodology has been applied. Sedimentological, geochemical, and biological analyses of the surface sediments and water samples were performed along the submerged beach. The data were integrated using a geographical information system, together with information on past and present land use and human activities along the coast and in inland regions. Heavy metal concentrations in sediments plus As and Se (Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Zn) and their enrichment factors, which are important for identifying polluted areas in countries like Italy (where environmental legislation has not yet established intervention limits), indicate excesses Cd, Cr, Pb, and V of probable anthropogenic origin. A microbiological contamination of marine waters has been detected by the Regional Environmental Protection Agency of Campania. The Bacteriological Quality Index map shows that bathing areas must be classified as “contaminated” and “highly contaminated”. High levels of chemical and biological contamination are particularly common in both bathing seawater and sediments along the coastal zone south of the Volturno River, where the existing wastewater treatment plant is not properly working, to date. Factory farming, which is widespread in the area, is likely to be an additional important source of contamination. In accordance with these conclusions, analyses of the benthic diatom community revealed dominance of eutrophic species.  相似文献   

Editorial Appreciation     

John Leibacher  Takashi Sakurai  Lidia van Driel-Gesztelyi 《Solar physics》2014,289(5):1455-1456

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