TY  - JOUR
A1  - Le Friant, A.
A1  - Ishizuka, O.
A1  - Boudon, G.
A1  - Palmer, M. R.
A1  - Talling, P. J.
A1  - Villemant, B.
A1  - Adachi, T.
A1  - Aljahdali, M.
A1  - Breitkreuz, C.
A1  - Brunet, M.
A1  - Caron, B.
A1  - Coussens, M.
A1  - Deplus, C.
A1  - Endo, D.
A1  - Feuillet, N.
A1  - Fraas, A. J.
A1  - Fujinawa, A.
A1  - Hart, M. B.
A1  - Hatfield, R. G.
A1  - Hornbach, M.
A1  - Jutzeler, M.
A1  - Kataoka, K. S.
A1  - Komorowski, J. -C.
A1  - Lebas, E.
A1  - Lafuerza, S.
A1  - Maeno, F.
A1  - Manga, M.
A1  - Martinez-Colon, M.
A1  - McCanta, M.
A1  - Morgan, S.
A1  - Saito, T.
A1  - Slagle, A.
A1  - Sparks, S.
A1  - Stinton, A.
A1  - Stroncik, Nicole
A1  - Subramanyam, K. S. V.
A1  - Tamura, Yui
A1  - Trofimovs, J.
A1  - Voight, B.
A1  - Wall-Palmer, D.
A1  - Wang, F.
A1  - Watt, S. F. L.
T1  - Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODP Expedition 340
JF  - Geochemistry, geophysics, geosystems
N2  - IODP Expedition 340 successfully drilled a series of sites offshore Montserrat, Martinique and Dominica in the Lesser Antilles from March to April 2012. These are among the few drill sites gathered around volcanic islands, and the first scientific drilling of large and likely tsunamigenic volcanic island-arc landslide deposits. These cores provide evidence and tests of previous hypotheses for the composition and origin of those deposits. Sites U1394, U1399, and U1400 that penetrated landslide deposits recovered exclusively seafloor sediment, comprising mainly turbidites and hemipelagic deposits, and lacked debris avalanche deposits. This supports the concepts that i/ volcanic debris avalanches tend to stop at the slope break, and ii/ widespread and voluminous failures of preexisting low-gradient seafloor sediment can be triggered by initial emplacement of material from the volcano. Offshore Martinique (U1399 and 1400), the landslide deposits comprised blocks of parallel strata that were tilted or microfaulted, sometimes separated by intervals of homogenized sediment (intense shearing), while Site U1394 offshore Montserrat penetrated a flat-lying block of intact strata. The most likely mechanism for generating these large-scale seafloor sediment failures appears to be propagation of a decollement from proximal areas loaded and incised by a volcanic debris avalanche. These results have implications for the magnitude of tsunami generation. Under some conditions, volcanic island landslide deposits composed of mainly seafloor sediment will tend to form smaller magnitude tsunamis than equivalent volumes of subaerial block-rich mass flows rapidly entering water. Expedition 340 also successfully drilled sites to access the undisturbed record of eruption fallout layers intercalated with marine sediment which provide an outstanding high-resolution data set to analyze eruption and landslides cycles, improve understanding of magmatic evolution as well as offshore sedimentation processes.
KW  - landslide
KW  - volcanic island
KW  - debris avalanche
KW  - seafloor sediment failure
KW  - tsunami
KW  - IODP
Y1  - 2015
U6  - https://doi.org/10.1002/2014GC005652
SN  - 1525-2027
VL  - 16
IS  - 2
SP  - 420
EP  - 442
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Houlahan, Jeff E.
A1  - Currie, David J.
A1  - Cottenie, Karl
A1  - Cumming, Graeme S.
A1  - Ernest, S. K. Morgan
A1  - Findlay, C. Scott
A1  - Fuhlendorf, Samuel D.
A1  - Gaedke, Ursula
A1  - Legendre, Pierre
A1  - Magnuson, John J.
A1  - McArdle, Brian H.
A1  - Muldavin, Esteban H.
A1  - Noble, David
A1  - Russell, Robert
A1  - Stevens, Richard D.
A1  - Willis, Trevor J.
A1  - Woiwod, Ian P.
A1  - Wondzell, Steve M.
T1  - Compensatory dynamics are rare in natural ecological communities
N2  - In population ecology, there has been a fundamental controversy about the relative importance of competition- driven (density-dependent) population regulation vs. abiotic influences such as temperature and precipitation. The same issue arises at the community level; are population sizes driven primarily by changes in the abundances of cooccurring competitors (i.e., compensatory dynamics), or do most species have a common response to environmental factors? Competitive interactions have had a central place in ecological theory, dating back to Gleason, Volterra, Hutchison and MacArthur, and, more recently, Hubbell's influential unified neutral theory of biodiversity and biogeography. If competitive interactions are important in driving year-to-year fluctuations in abundance, then changes in the abundance of one species should generally be accompanied by compensatory changes in the abundances of others. Thus, one necessary consequence of strong compensatory forces is that, on average, species within communities will covary negatively. Here we use measures of community covariance to assess the prevalence of negative covariance in 41 natural communities comprising different taxa at a range of spatial scales. We found that species in natural communities tended to covary positively rather than negatively, the opposite of what would be expected if compensatory dynamics were important. These findings suggest that abiotic factors such as temperature and precipitation are more important than competitive interactions in driving year-to-year fluctuations in species abundance within communities.
Y1  - 2007
UR  - http://www.pnas.org/
U6  - https://doi.org/10.1073/pnas.0603798104
SN  - 0027-8424
ER  - 
TY  - JOUR
A1  - Starkenburg, Else
A1  - Martin, Nicolas
A1  - Youakim, Kris
A1  - Aguado, David S.
A1  - Allende Prieto, Carlos
A1  - Arentsen, Anke
A1  - Bernard, Edouard J.
A1  - Bonifacio, Piercarlo
A1  - Caffau, Elisabetta
A1  - Carlberg, Raymond G.
A1  - Cote, Patrick
A1  - Fouesneau, Morgan
A1  - Francois, Patrick
A1  - Franke, Oliver
A1  - Gonzalez Hernandez, Jonay I.
A1  - Gwyn, Stephen D. J.
A1  - Hill, Vanessa
A1  - Ibata, Rodrigo A.
A1  - Jablonka, Pascale
A1  - Longeard, Nicolas
A1  - McConnachie, Alan W.
A1  - Navarro, Julio F.
A1  - Sanchez-Janssen, Ruben
A1  - Tolstoy, Eline
A1  - Venn, Kim A.
T1  - The Pristine survey - I. Mining the Galaxy for the most metal-poor stars
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present the Pristine survey, a new narrow-band photometric survey focused on the metallicity-sensitive Ca H&K lines and conducted in the Northern hemisphere with the wide-field imager MegaCam on the Canada-France-Hawaii Telescope. This paper reviews our overall survey strategy and discusses the data processing and metallicity calibration. Additionally we review the application of these data to the main aims of the survey, which are to gather a large sample of the most metal-poor stars in the Galaxy, to further characterize the faintest Milky Way satellites, and to map the (metal-poor) substructure in the Galactic halo. The current Pristine footprint comprises over 1000 deg(2) in the Galactic halo ranging from b similar to 30 degrees to similar to 78 degrees and covers many known stellar substructures. We demonstrate that, for Sloan Digital Sky Survey (SDSS) stellar objects, we can calibrate the photometry at the 0.02-mag level. The comparison with existing spectroscopic metallicities from SDSS/Sloan Extension for Galactic Understanding and Exploration (SEGUE) and Large Sky Area Multi-Object Fiber Spectroscopic Telescope shows that, when combined with SDSS broad-band g and i photometry, we can use the CaHK photometry to infer photometric metallicities with an accuracy of similar to 0.2 dex from [Fe/H] = -0.5 down to the extremely metal-poor regime ([Fe/H] < -3.0). After the removal of various contaminants, we can efficiently select metal-poor stars and build a very complete sample with high purity. The success rate of uncovering [Fe/H](SEGUE) < -3.0 stars among [Fe/H](Pristine) < -3.0 selected stars is 24 per cent, and 85 per cent of the remaining candidates are still very metal poor ([Fe/H]<-2.0). We further demonstrate that Pristine is well suited to identify the very rare and pristine Galactic stars with [Fe/H] < -4.0, which can teach us valuable lessons about the early Universe.
KW  - stars: abundances
KW  - Galaxy: abundances
KW  - Galaxy: evolution
KW  - Galaxy: formation
KW  - Galaxy: halo
KW  - galaxies: dwarf
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx1068
SN  - 0035-8711
SN  - 1365-2966
VL  - 471
SP  - 2587
EP  - 2604
PB  - Oxford Univ. Press
CY  - Oxford
ER  -