caa a22 4500 467889996 CHVBK 20180406152746.0 cr unu---uuuuu 170328e20060901xx s 000 0 eng 10.1007/s00710-006-0151-7 doi (NATIONALLICENCE)springer-10.1007/s00710-006-0151-7 Smith D. C. Laboratoire de Tectonique, CNRS/UMR7072, Université Paris VI, Paris, France aut The SHAND quaternary system for evaluating the supersilicic or subsilicic crystal-chemistry of eclogite minerals, and potential new UHPM pyroxene and garnet end-members [Elektronische Daten] [D. C. Smith] Summary: The stoichiometry of pyroxenes {viiiX2+ viY2+ ivZ4+ 2 O6} and garnets {xiiX2+ 3 viY3+ 2 ivZ4+ 3 O12} is re-evaluated by a theoretical crystal-chemical approach that takes into account natural phenomena that do not fit with conventional anhydrous stoichiometric mineralogy: the existence in eclogites of microinclusions of other minerals that may have been exsolved from previous supersilicic or subsilicic UHPM pyroxene or garnet. Different definitions of supersilicic and subsilicic are discussed and the one based on the ability to exsolve SiO2 and leave behind a stoichiometric pyroxene or garnet is recommended for general adoption. The SHAND system (S = Si et al.; H = H; A = Al et al.; N = Na et al.; D = divalents) for projecting multivariate chemical space involving 23 cations and 104 selected natural or potential mineral species on to two essential diagrams (SAND and SHND) is described in full for the first time. Numerous possible chemical exchanges are considered and justified with respect to known mineral phenomena such as cation vacancies, octahedral silicon or protonation. Several new potential end-members are presented, in particular "supersilipyx”, "supersiligar” and "subsiligar”. It is suggested that small quantities of these end-members can be incorporated into UHPM solid-solutions and lead to various exsolution phenomena during eclogite exhumation. Springer-Verlag, 2006 Mineralogy and Petrology Springer-Verlag 88/1-2(2006-09-01), 87-122 0930-0708 88:1-2<87 2006 88 710 https://doi.org/10.1007/s00710-006-0151-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-006-0151-7 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Smith D. C. Laboratoire de Tectonique, CNRS/UMR7072, Université Paris VI, Paris, France aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer-Verlag 88/1-2(2006-09-01), 87-122 0930-0708 88:1-2<87 2006 88 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer