Nature Geoscience contents: November 2013 Volume 6 Number 11 pp891-986

TABLE OF CONTENTS November 2013 Volume 6, Issue 11 Editorial Commentaries In the press Research Highlights News and Views Perspective Progress Article Review Letters Articles Subscribe   Facebook   RSS   Recommend to library   Twitter   Editorial Top Expanding boundaries of exploration   p891 doi:10.1038/ngeo2006 Mineral exploration is pushing new frontiers. Given a poor track record on land, mining practises should be honed on home soil before venturing into the oceans. Commentaries Top Road map to mineral supply   pp892 - 894 Richard Herrington doi:10.1038/ngeo1947 Access to metals and minerals is restricted mostly by geopolitical constraints, and not by a shortage of mineable deposits. In the face of rising demand, a full inventory of these commodities — in the Earth's crust as well as in recyclable waste — is urgently required. Metals for a low-carbon society   pp894 - 896 Olivier Vidal, Bruno Goffe & Nicholas Arndt doi:10.1038/ngeo1993 Renewable energy requires infrastructures built with metals whose extraction requires more and more energy. More mining is unavoidable, but increased recycling, substitution and careful design of new high-tech devices will help meet the growing demand. The phosphorus trilemma   pp897 - 898 Michael Obersteiner, Josep Penuelas, Philippe Ciais, Marijn van der Velde & Ivan A. Janssens doi:10.1038/ngeo1990 Mineable phosphorus reserves are confined to a handful of countries. Reductions in wastage could free up this resource for low-income, food-deficient countries. In the press Top Tilting at Europa   p899 Emily Lakdawalla doi:10.1038/ngeo1998 Research Highlights Top Volcanology: Shaky caldera | Palaeoecology: Nutrients in the wind | Chemical oceanography: Physical flux | Planetary science: Cloudy Mars News and Views Top Atmospheric science: Rainfall's oceanic underpinnings   pp901 - 902 John Fasullo doi:10.1038/ngeo1997 Understanding the processes that govern the complex spatial structure of rainfall is crucial. Idealized numerical simulations reveal the strong influence that ocean heat transport exerts on this structure. See also: Letter by Frierson et al. Volcanology: Magma giant   pp902 - 903 Gabriele Uenzelmann-Neben doi:10.1038/ngeo1958 Episodes of excessive magmatism have repeatedly formed large volcanic provinces on Earth. Seismic data from the Shatsky Rise in the northwestern Pacific Ocean reveal that such oceanic plateaux can be built from individual, giant volcanoes. See also: Article by Sager et al. Palaeoclimate: Biodiversity-dominated feedback   pp903 - 904 Stefan C. Dekker doi:10.1038/ngeo1989 About 5,500 years ago, there was a shift from savannah to desert vegetation in the Sahara. Conceptual modelling suggests that the transition was controlled by a climate–vegetation feedback that was also influenced by plant diversity. See also: Letter by Claussen et al. Geoscience JOBS of the week Faculty Recruitment for a Multidisciplinary Initiative in Coastal and Marine Research Florida State University Materials Simulation of Amorphous Materials Paul Voyles and Dane Morgan Chair, Department of Geological Sciences University of Delaware More Science jobs from Perspective Top Continental-root control on the genesis of magmatic ore deposits   pp905 - 910 W. L. Griffin, G. C. Begg & Suzanne Y. O'Reilly doi:10.1038/ngeo1954 Some giant ore deposits are formed from magma, but the precise controls on their formation are unclear. A Perspective article analyses the distribution of some diamond, platinum-group element and gold deposits worldwide, and suggests that the structure and composition of sub-continental lithospheric mantle could play a role in ore genesis. Progress Article Top Giant ore deposits formed by optimal alignments and combinations of geological processes   pp911 - 916 Jeremy P. Richards doi:10.1038/ngeo1920 Giant ore deposits are priority targets for mining companies. A review of the characteristics of several giant porphyry and epithermal deposits worldwide suggests that they formed from ordinary processes that were fortuitously operating at maximum efficiency. Review Top Triggers for the formation of porphyry ore deposits in magmatic arcs   pp917 - 925 Jamie J. Wilkinson doi:10.1038/ngeo1940 Porphyry ore deposits supply much of the copper, molybdenum, gold and silver used by humans. A review of the main processes that trigger porphyry ore formation suggests that sulphide saturation of the magmas that supply the metals could be the overriding mechanism that helps control the temporal and spatial distribution of the ore deposits. Letters Top Experimental evidence for a phase transition in magnesium oxide at exoplanet pressures   pp926 - 929 F. Coppari, R. F. Smith, J. H. Eggert, J. Wang, J. R. Rygg et al. doi:10.1038/ngeo1948 Little is known about the structure of possible mantle materials of extra-solar super-Earths with interior pressures of up to 1,000 GPa. Dynamic X-ray diffraction measurements of ramp-compressed magnesium oxide, an important component of Earth's mantle, show a solid–solid state transition at about 600 GPa, with a high-pressure structure that is stable up to 900 GPa. Transport-driven formation of a polar ozone layer on Mars   pp930 - 933 Franck Montmessin & Franck Lefèvre doi:10.1038/ngeo1957 Spectral observations from the Mars Express spacecraft have revealed an ozone layer that forms at night in south polar Mars. Data analysis and climate models suggest that poleward transport of oxygen and seasonal changes in hydrogen radicals explain the ozone layer's presence in the southern hemisphere, and its absence in the north. Link between Antarctic ozone depletion and summer warming over southern Africa   pp934 - 939 Desmond Manatsa, Yushi Morioka, Swadhin K. Behera, Toshi Yamagata & Caxton H. Matarira doi:10.1038/ngeo1968 The recent rise in surface air temperatures over southern Africa is thought to largely result from the increase in atmospheric greenhouse gas concentrations. An analysis of climate data from the past four decades suggests that the warming may be linked to changes in Southern Hemisphere circulation induced by Antarctic ozone loss. Contribution of ocean overturning circulation to tropical rainfall peak in the Northern Hemisphere   pp940 - 944 Dargan M. W. Frierson, Yen-Ting Hwang, Neven S. Fučkar, Richard Seager, Sarah M. Kang et al. doi:10.1038/ngeo1987 In the tropics, substantially more rain falls just north of the Equator. An analysis of satellite observations, reanalysis data and model simulations suggests that the meridional ocean overturning circulation contributes significantly to the tropical rainfall peak north of the Equator. See also: News and Views by Fasullo Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet   pp945 - 948 Anne M. Le Brocq, Neil Ross, Jennifer A. Griggs, Robert G. Bingham, Hugh F. J. Corr et al. doi:10.1038/ngeo1977 Subglacial meltwater channels beneath the Antarctic Ice Sheet have been reported, but the nature and distribution of these meltwater pathways are unclear. Remote sensing observations reveal persistent channelized features beneath the Filchner–Ronne Ice Shelf in West Antarctica, suggesting widespread channelized flow driven by melting. A weak El Niño/Southern Oscillation with delayed seasonal growth around 4,300 years ago   pp949 - 953 H. V. McGregor, M. J. Fischer, M. K. Gagan, D. Fink, S. J. Phipps et al. doi:10.1038/ngeo1936 Palaeoclimate records indicate lower El Niño/Southern Oscillation (ENSO) variance during the middle Holocene compared with today, but the mechanisms leading to this muted variability are not clear. A 175-year oxygen isotope record from a Porites coral microatoll in the NINO3.4 region records persistently reduced ENSO variance about 4,300 years ago, and season-specific analyses of the record suggest that insolation played an important role in this change. Simulated climate–vegetation interaction in semi-arid regions affected by plant diversity   pp954 - 958 M. Claussen, S. Bathiany, V. Brovkin & T. Kleinen doi:10.1038/ngeo1962 The end of the African Humid Period about 6,000 years ago was associated with vegetation change and decreased precipitation. Conceptual modelling suggests that the nature of the feedback between climate and vegetation is dependent on vegetation type and diversity. See also: News and Views by Dekker Meridional shifts of the Atlantic intertropical convergence zone since the Last Glacial Maximum   pp959 - 962 Jennifer A. Arbuszewski, Peter B. deMenocal, Caroline Cléroux, Louisa Bradtmiller & Alan Mix doi:10.1038/ngeo1961 The position of the intertropical convergence zone is thought to be linked to changes in the Earth's climate state. Analyses of marine sediment show that over the past 25,000 years, the intertropical convergence zone over the Atlantic Ocean migrated in response to climate changes. Hidden hotspot track beneath the eastern United States   pp963 - 966 Risheng Chu, Wei Leng, Don V. Helmberger & Michael Gurnis doi:10.1038/ngeo1949 The surface expressions of mantle plumes—known as hotspot tracks—are rarely observed on continents because the lithosphere is so thick. Analysis of seismic data from the eastern United States, combined with geodynamical modelling, reveals a linear, east–west-trending seismic anomaly that may represent a hidden hotspot track extending from Missouri to Virginia. Ephemeral isopycnicity of cratonic mantle keels   pp967 - 970 David W. Eaton & H. K. Claire Perry doi:10.1038/ngeo1950 The long-term stability of the continents has been attributed to a trade-off between thermal and compositional effects. Numerical simulations of the evolution of continents over 3 billion years, however, show that this state is ephemeral, and continents that are neutrally buoyant today were more (or less) buoyant in the geologic past. Formation of an interconnected network of iron melt at Earth's lower mantle conditions   pp971 - 975 Crystal Y. Shi, Li Zhang, Wenge Yang, Yijin Liu, Junyue Wang et al. doi:10.1038/ngeo1956 The differentiation of the Earth into mantle and core implies that there is a mechanism to separate iron from silicates. Three-dimensional imaging of samples experimentally subjected to high pressures reveals that liquid iron forms interconnected melt networks at lower mantle conditions, suggesting pathways through which iron can percolate towards the core. Articles Top An immense shield volcano within the Shatsky Rise oceanic plateau, northwest Pacific Ocean   pp976 - 981 William W. Sager, Jinchang Zhang, Jun Korenaga, Takashi Sano, Anthony A. P. Koppers et al. doi:10.1038/ngeo1934 The structure of oceanic plateaux is unclear, as they are remote and submerged beneath the seas. Seismic images of the Tamu Massif, part of the Shatsky Rise oceanic plateau in the northwestern Pacific Ocean, show that it is a single immense volcano, potentially the largest on Earth. See also: News and Views by Uenzelmann-Neben Helium in Earth's early core   pp982 - 986 M. A. Bouhifd, Andrew P. Jephcoat, Veronika S. Heber & Simon P. Kelley doi:10.1038/ngeo1959 Some mantle plumes are enriched in 3He, but the source of this primordial isotope is unclear. The partitioning behaviour of helium between silicate and iron melts—as determined by experiments—suggests that sufficient helium may have been incorporated into the core when the Earth differentiated to explain the anomalous leakage at the Earth's surface. Top Natureevents is a fully searchable, multi-disciplinary database designed to maximise exposure for events organisers. The contents of the Natureevents Directory are now live. The digital version is available here. Find the latest scientific conferences, courses, meetings and symposia on natureevents.com. For event advertising opportunities across the Nature Publishing Group portfolio please contact natureevents@nature.com More Nature Events

You have been sent this Table of Contents Alert because you have opted in to receive it. You can change or discontinue your e-mail alerts at any time, by modifying your preferences on your nature.com account at: www.nature.com/myaccount (You will need to log in to be recognised as a nature.com registrant) For further technical assistance, please contact our registration department For print subscription enquiries, please contact our subscription department For other enquiries, please contact our customer feedback department Nature Publishing Group | 75 Varick Street, 9th Floor | New York | NY 10013-1917 | USA Nature Publishing Group's worldwide offices: London - Paris - Munich - New Delhi - Tokyo - Melbourne San Diego - San Francisco - Washington - New York - Boston Macmillan Publishers Limited is a company incorporated in England and Wales under company number 785998 and whose registered office is located at Brunel Road, Houndmills, Basingstoke, Hampshire RG21 6XS. © 2013 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.