GGR Biennial Critical Review: Analytical Developments Since 2012     

Michael Wiedenbeck  L. Paul Bédard  Roxana Bugoi  Mary Horan  Kathryn Linge  Silke Merchel  Luiz F. G. Morales  Dany Savard  A. Kate Souders  Paul Sylvester 《Geostandards and Geoanalytical Research》2014,38(4):467-512

Advances in the chemical, crystallographic and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware or to innovative approaches to data acquisition and/or its interpretation. This biennial review addresses key laboratory methods that form much of the foundation for analytical geochemistry; again, this contribution is presented as a compendium of laboratory techniques. We highlight advances that have appeared since January 2012 and that are of particular significance for the chemical and isotopic characterisation of geomaterials. Prominent scientists from the selected analytical fields present publications they judge to be particular noteworthy, providing background information about the method and assessing where further opportunities might be anticipated. In addition to the well‐established technologies such as thermal ionisation mass spectrometry and plasma emission spectroscopy, this publication also presents new or rapidly growing methods such as electron backscattered diffraction analysis and atom probe tomography – a very sensitive method providing atomic scale information.  相似文献   

Decay mechanism of indoor porous opuka stone: a case study from the main altar located in the St. Vitus Cathedral,Prague (Czech Republic)     

Richard Přikryl  Jiřina Přikrylová  Martin Racek  Zuzana Weishauptová  Kateřina Kreislová 《Environmental Earth Sciences》2017,76(7):290

A carving of the indoor main altar of St. Vitus Cathedral in Prague (Czech Republic) is made of the opuka stone—a clayey–calcareous silicite—which now exhibits the development of decay phenomena such as the formation of salt-laden case-hardened subsurface layer (approx. 150 mm thick), with detachment of the case-hardened layer manifested by blistering and/or flaking. Formation of this gypsum-rich layer is linked to the reaction of components (SO₂) from polluted air (both outdoor and indoor) and from the rock itself (calcium ion from calcite). Development of brittle damage in the subsurface layer and underlying stone is interpreted based on the results from previous environmental monitoring in the Cathedral’s interior, which indicated highly fluctuating temperature and humidity, resulting in a hygrothermal stress in the material described by the “double-layer sandwich” model. The sensitivity of the studied stone to the above-mentioned processes is evidenced by its microstructural properties, specifically parameters of the pore spaces which indicate an extremely high susceptibility to damage by the actions of freezing water and/or salt crystallisation.  相似文献