Dear MSA Members, Apologies for the delay; Happy New Year to all... Below are Editors' picks of notable articles, and the full Table of Contents, for this month’s issue of the American Mineralogist: Journal of Earth and Planetary Materials . You may view the American Mineralogist Noted Papers at http://www.minsocam.org/MSA/Ammin/AM_Notable_Articles.html , or click on the page numbers below. If you are not already logged into GeoScience World, then from the American Mineralogist menu on http://www.minsocam.org/ , go to " Online Access to MSA Publications " - look for and select the "portal page" link, to access GeoScience World. Once at the portal page, enter your user name (e-mail address), and your password (membership number). Sincerely, Keith Putirka Ian Swainson Editors Selections, December 2016 Invited Centennial Articles Predicting Trace Element Partitioning Behavior On page 2577 of this issue, Sun -ichiro Karato provides a review of the physical basis for contrasts in partition coefficients. This review attempts to explain a suite of experimental observations, which include the now-familiar Onuma diagrams, so well developed by Blundy and Wood and others, which show how partition coefficients vary with an element’s size and charge, but the physical reasons for the dependence of element partitioning on the size of element have been unclear particularly for noble gas elements. Karato developed new models of element partitioning using the models of point defects in minerals and the hard sphere model of silicate melts. Karato’s model provides a physical explanation, for example, as to why some phases partition noble gases in proportion to their ionic radii (bridgemanite), while other silicate phases (Ol, Cpx) do not. Karato finds that his models may help better describe and predict partitioning behavior. But Karato also concludes that no physical model can yet satisfactorily predict P-T dependencies of trace element partitioning, and hence that there is still no substitute for a thermodynamic description of partitioning behavior. Mineralogists at the Forefront of Human Health On page 2594 of this issue, Jill Pasteris demonstrates why the demarcation between biogenic, synthetic, and inorganic phases is not a simple one, and may erect unfruitful barriers at least in some sub-disciplines of medicine, mineralogy, and materials science. Here, Pasteris examines apatitic “biomaterials”, which are defined as the synthetic forms of hydroxylapatite (usually nanocrystalline, in some cases inter-bonded with organic molecules) that are used to replace natural bone and tooth materials. Her review illustrates the various ways in which biomaterials are structured and synthesized, with some fascinating insights into how subtle variations in synthesis conditions can tailor the required properties of a mineral to a given biologic function and determine how successfully such materials will operate when implanted in a human system. The take-home message of this review is that mineralogists have much to offer to such research, and argues that “biomaterials” should be pursued as a major sub-discipline of mineralogical research. As editors, we happily await the continued publication of papers in this field. Articles Immobilizing Radionuclides With Apatite On page 2611 of this issue, Rigali et al. review the various ways in which apatite can be used to isolate a wide range of radionuclides from the near-surface environment. These means of radionuclide neutralization include the familiar modes of surface adsorption and partitioning of species into apatite structures. Rigali et al. also review what may be less familiar mechanisms, such as dissolution/(re-)precipitation reactions that are now being used to remediate contaminated groundwater or act as semi-permeable membranes. For example, some recent studies have shown that apatite can dissolve in the presence of U-bearing fluids to re-precipitate as U-phosphate or U-carbonate, and that the addition of hydroxyapatite to contaminated soils may reduce U concentrations in pore waters to levels deemed safe for drinking. A Depth Continuum of Water Release During Subduction On page 2645 of this issue Gemmi et al. employ cutting edge analytical techniques to determine the structures of two important candidates for carriers of water into the deep mantle: the “11.5 angstrom” phase, Mg 6 Al(OH) 7 (SiO 4 ) 2 , and the HySo phase, Mg 3 Al(OH) 3 (Si 2 O 7 ). These phases can form by the breakdown of chlinochlore and so may carry water to depths beyond clinochlore and chlorite breakdown. These phases lack the H-bonded, infinite tetrahedral sheets structure of precursor silicates. The authors find structures with reduced Si-O-Si interconnections and much higher density. Thus, these high-density phases, which can contain between 8-13 wt% H 2 O, are expected to be stable to much greater depths. Evidence for Mantle Global Warming? On page 2768 of this issue, Ganne et al. present an analysis of global magmatic temperatures from published data that span the temporal range of 600 Ma to present. Their most dramatic finding is that magmatic temperatures, as measured from whole rock and mineral compositions, record a maximum that falls between 325-125 Ma; these ages are the bookends of the lifespan of Pangea. This time period also coincides with a peak in mantle potential temperature. The authors suggest that these findings support numerical models (e.g., Coltice et al. 2009; Van Avendonk et al. 2016) whereby supercontinent formation results in both thermal insulation, and a disruption of mantle convection, such that increased temperatures temporarily influence supercontinent volcanism. Coltice et al. predict that supercontinent-induced heating should be <100 °C; Ganne et al. identify some key targets for high precision thermometry, as a test of the Coltice et al. model. Predicting Mining Accidents, Building Collapse, Etc. On page 2751 of this issue Jiang et al. provide an update of prior work that indicated that acoustic emissions presage mine collapse. In this new work, the authors present experimental results that confirm that acoustic emissions increase just prior to the collapse of cavities in sandstone and coal. The energy released by such acoustic emissions can be described by a power law, with slightly different exponents for different materials, but the exponents also change with time. A key result then is that collapse of a mine shaft, or bridge or building, may be presaged by both acoustic emissions and their energies. Another fascinating result is that cavity collapse yields a power law with an exponent greater than that associated with crack propagation, the latter being associated with micro-faults and earthquakes. A New Hygrometer and Shallow Magma Accelerations at Etna On page 2774 of this issue, in a Letter, Perinelli et al. re-calibrate their clinopyroxene-based hygrometer. The original, and new model, are applicable to trachyte or hawaiiite-type basalts. But while magmatically restrictive, the model predicts water contents without precise knowledge of liquid composition, relying on pyroxene components and the P-T conditions of crystallization. They find that at Mt Etna, magmas begin to dehydrate mostly at a <400 MPa and lose most of their water at pressure of <100 MPa. This result corroborates inferences form melt inclusions, and it indicates that eruption triggering, and magma transport acceleration due to dehydration, are mostly relatively shallow processes, at least in the Etnean plumbing system. American Mineralogist Volume 101; Number 12; all were live online Dec 1, 2016 2577 Physical basis of trace element partitioning: A review. Shun-ichiro Karato 2594 A mineralogical view of apatitic biomaterials. Jill Dill Pasteris 2611 Radionuclide removal by apatite. Mark J. Rigali, Patrick V. Brady, and Robert C. Moore 2620 Hydrothermal mineral replacement reactions for an apatite-monazite assemblage in alkali-rich fluids at 300-600 °C and 100 MPa. Wladyslaw B. Betkowski, Daniel E. Harlov, and John F. Rakovan 2638 Raman spectroscopy of siderite at high pressure: Evidence for a sharp spin transition. Jan Müller, Sergio Speziale, Ilias Efthimiopoulos, Sandro Jahn, Monika Koch-Müller 2645 Electron diffraction determination of 11.5 Å and HySo structures: Candidate water carriers to the Upper Mantle Mauro Gemmi, Marco Merlini, Lukas Palatinus, Patrizia Fumagalli, and Michael Hanfland 2655 Influence of grain size, water and deformation on dolomite reaction rim formation. Vanessa Helpa, Erik Rybacki, Luiz Morales, and Georg Dresen 2666 Dissolution-reprecipitation and self-assembly of serpentine nanoparticles preceding chrysotile formation: Insights into the structure of proto-serpentine. Romain Lafay, Alejandro Fernandez-Martinez, German Montes-Hernandez, Anne-Line Auzende, and Agnieszka Poulain 2677 Submicrometer-scale spatial heterogeneity in silicate glasses using aberration-corrected scanning transmission electron microscopy. Katherine D. Burgess, Rhonda M. Stroud, M. Darby Dyar, and Molly C. McCanta 2689 Growth of hydrothermal baddeleyite and zircon in different stages of skarnization. Wen Zhao, Mei-Fu Zhou, and Wei Terry Chen 2701 Structural incorporation of W 6+ into hematite and goethite: A combined study of natural and synthetic iron oxides developed from precursor ferrihydrite and the preservation of ancient fluid compositions in hematite. Stefan Kreissl, Ralph Bolanz, Jörg Göttlicher, Ralph Steininger, Mihail Tarassov, and Gregor Markl 2716 Morphological and chemical evolution of corundum (ruby and sapphire): crystal ontogeny reconstructed by EMPA, LA-ICP-MS, and Cr 3+ Raman mapping. Elena S. Sorokina, Wolfgang Hofmeister, Tobias Häger, Regina Mertz-Kraus, Stefan Buhre, and John Saul 2723 High-pressure compressibility and vibrational properties of (Ca,Mn)CO 3 . Jin Liu, Razvan Caracas, Dawei Fan, Ema Bobocioiu, Dongzhou Zhang, and Wendy Mao 2731 Transformation of pyrite to pyrrhotite in the presence of Au-Ag alloys at 500 ºC. Galina Aleksandrovna Palyanova, Konstantin Kokh, and Yuri V. Seryotkin 2738 An alternative method of calculating cleavage energy: The effect of ion clusters in micas. Maria Franca Brigatti, Chiara Elmi, Stephen J. Guggenheim, Daniele Malferrrari, and Marco Poppi 2747 The role of Fe content on the Fe-Mg exchange reaction in augite. Matteo Alvaro, Mara Murri, Lorenzo Scandolo, Anna Fioretti, Fabrizio Nestola, and Maria Chiara Domeneghetti 2751 Collapsing minerals: Crackling noise of sandstone and coal, and the predictability of mining accidents. Xiang Jiang , Deyi Jiang , Jie Chen , Ekhard K.H. Salje 2759 Magnetite exsolution in ilmenite from the Fe-Ti oxide gabbro in the Xinjie intrusion (SW China) and sources of unusually strong remnant magnetization. Wei Tan, Hongping He, Christina Yan Wang, Huang Dong, Xiaoliang Liang, and Jianxi Zhu 2768 Statistical petrology reveals a link between supercontinents cycle and mantle global climate. Jérôme Ganne, Xiaojun Feng , Patrice Rey , Vincent De Andrade 2774 An improved clinopyroxene-based hygrometer for Etnean magmas and implications for eruption triggering mechanisms. Cristina Perinelli, Silvio Mollo, Silvio Mollo, Mario Gaeta, Serena Pia De Cristofaro, Danilo M. Palladino, Pietro Armienti, Piergiorgio Scarlato, and Keith D. Putirka 2778 New Mineral Names Keith Putirka Dept. Earth & Env. Sciences California State University, Fresno 2576 E. San Ramon Ave. M/S ST24 93740 559-278-4524 kputirka@csufresno.edu