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Melt migration in basalt columns driven by crystallization-induced pressure gradients
The internal textures of columnar-jointed lava flows and intrusions are poorly understood. Mattssonet al. propose a melt-migration model for Icelandic basalt driven by crystallization and volume decrease inside cooling columns, which explains the macroscopic features observed in columnar-jointed basalts.
- Hannes B. Mattsson
- , Luca Caricchi
- & Ann M. Hirt
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| Open AccessSouth China Sea hydrological changes and Pacific Walker Circulation variations over the last millennium
Tropical Pacific hydrology affects the global climate through the strength of the Pacific Walker Circulation. Yanet al. reconstruct variations in the Pacific Walker Circulation in the South China Sea over the last millennium and find that less precipitation fell during warmer and more rainfall during cool periods.
- Hong Yan
- , Liguang Sun
- & Wenhan Cheng
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| Open AccessMapping the evolving strain field during continental breakup from crustal anisotropy in the Afar Depression
The spatial and temporal scales over which continental breakup occurs by mechanical deformation and magma intrusion remain controversial. Keiret al. quantify anisotropy across the Afar Triple Junction using S-wave splitting from earthquakes to evaluate the strain in a region of continental breakup.
- Derek Keir
- , M. Belachew
- & J.V. Rowland
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Prevailing oxic environments in the Pacific Ocean during the mid-Cretaceous Oceanic Anoxic Event 2
The second oceanic anoxic event occurred 94 million years ago and constituted a very large perturbation of the Earth's carbon cycle. Here, the authors study carbon isotopes and degrees of pyritization and demonstrate that, unlike other oceans, the Pacific remained oxygenated for most of this period.
- Reishi Takashima
- , Hiroshi Nishi
- & Keiichi Hayashi
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| Open AccessMultiple S-isotopic evidence for episodic shoaling of anoxic water during Late Permian mass extinction
A final catastrophe killed 90% of marine species at the end of the Permian period, but significant biodiversity loss preceded this event. In this study, sulphur isotope evidence suggests that incursion of anoxic water into shallow regions may have contributed to biodiversity loss.
- Yanan Shen
- , James Farquhar
- & Boswell A. Wing
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New silica clathrate minerals that are isostructural with natural gas hydrates
Clathrates are minerals with cage-like structural voids that can be filled by guest species; three types are plausible but only one has been observed in nature. Mommaet al. have discovered the remaining two types in Japanese marine sediments, and determined their structural similarity to natural gas hydrates.
- Koichi Momma
- , Takuji Ikeda
- & Yasuhiro Kudoh
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Historical land use change has lowered terrestrial silica mobilization
Continental export of silicon to the coast is linked to ocean carbon sinks, but terrestrial silicon fluxes have not been quantified. Here, human deforestation and cultivation of the landscape are shown to be the most important factors in silicon mobilization in temperate European watersheds.
- Eric Struyf
- , Adriaan Smis
- & Patrick Meire
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| Open AccessDiscovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge
The Arctic Mid-Ocean Ridge spreads extremely slowly and hydrothermal vent fields have not been reported in its vicinity. Pedersenet al. describe a black smoker vent field with large hydrothermal deposits and novel fauna distinct from those found in similar environments in the Atlantic.
- Rolf B. Pedersen
- , Hans Tore Rapp
- & Steffen L. Jorgensen
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Evidence for infragravity wave-tide resonance in deep oceans
Ocean tides and infragravity waves—the Earths 'hum'—have very different periods and wavelengths. Sugioka and colleagues report resonance between these two phenomena using arrays of broadband ocean-bottom seismometers and show that some tidal energy is transferred to the deep oceans through this coupling.
- Hiroko Sugioka
- , Yoshio Fukao
- & Toshihiko Kanazawa
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Crustaceans from bitumen clast in Carboniferous glacial diamictite extend fossil record of copepods
Copepod crustaceans are extremely abundant but fossilize poorly given their fragility; the earliest known fossils are from the Cretaceous period. Selden and colleagues report copepod fossils dating from the Carboniferous in a bitumen clast in Oman, extending their fossil record by 188 million years.
- Paul A. Selden
- , Rony Huys
- & Paul N. Taylor
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A new Argentinean nesting site showing neosauropod dinosaur reproduction in a Cretaceous hydrothermal environment
Dinosaur nesting sites have been found in many different places, but the factors that influenced the choice of location are unclear. Here, a sauropod nesting site is described in a geothermal setting in the Sanagasta Valley, suggesting that the dinosaurs used the warm environment to favour the incubation process.
- Gerald Grellet-Tinner
- & Lucas E. Fiorelli