Big, old and complicated - p665

doi:10.1038/ngeo654

Earth scientists learn to approach scientific questions from a unique perspective — one that Charles Darwin shared.

Full Text - Big, old and complicated | PDF (80 KB) - Big, old and complicated

Fake plastic trees - p665

doi:10.1038/ngeo655

Greenhouse-gas emissions keep rising, despite all efforts at regulation and international agreement. Geoengineering could provide a back-up plan.

Full Text - Fake plastic trees | PDF (80 KB) - Fake plastic trees

Man, myth, geologist - pp666 - 667

Mott T. Greene

doi:10.1038/ngeo646

Charles Darwin became the founder and mythic hero of modern evolutionary biology with the publication of his work On the Origin of Species 150 years ago. The book bears the signature of a geological thinker who had turned to a faster-moving discipline.

Full Text - Man, myth, geologist | PDF (255 KB) - Man, myth, geologist

As Darwin wrote - p668

Alicia Newton reviews Charles Darwin's Notebooks From the Voyage of the Beagle by Gordon Chancellor & John van Wyhe

doi:10.1038/ngeo648

Full Text - As Darwin wrote | PDF (224 KB) - As Darwin wrote

Exhibition: Darwin on the rocks - pp668 - 669

doi:10.1038/ngeo649

Full Text - ExhibitionDarwin on the rocks | PDF (224 KB) - ExhibitionDarwin on the rocks

Our choice from the recent literature - p670

doi:10.1038/ngeo653

Full Text - Our choice from the recent literature | PDF (156 KB) - Our choice from the recent literature

Tectonics: Antarctica sinking - pp671 - 672

Michael Studinger & Peter Barrett

doi:10.1038/ngeo644

Conflicting proxies for the size of early Antarctic ice sheets have been puzzling. A reconstruction of West Antarctica's past elevation suggests that the disagreement stems from an underestimation of Antarctica's surface area above sea level.

Full Text - TectonicsAntarctica sinking | PDF (928 KB) - TectonicsAntarctica sinking

Subject Category: Structural geology, tectonics and geodynamics

Palaeoclimate: Potomac paradise - p672

Alicia Newton

doi:10.1038/ngeo651

Full Text - PalaeoclimatePotomac paradise | PDF (145 KB) - PalaeoclimatePotomac paradise

Palaeomagnetism: In GAD we trust - pp673 - 674

Joseph G. Meert

doi:10.1038/ngeo635

Palaeomagnetists' basic assumption that Earth's magnetic field is a GAD, that is, a geocentric axial dipole, has been challenged by anomalous magnetic data from ancient Canadian basalts. At a closer look, fast continental drift could explain this anomaly.

Full Text - PalaeomagnetismIn GAD we trust | PDF (264 KB) - PalaeomagnetismIn GAD we trust

Subject Category: Geomagnetism, palaeomagnetism and core processes

See also: Letter by Swanson-Hysell et al.

Biogeochemistry: Fire's black legacy - pp674 - 675

Caroline M. Preston

doi:10.1038/ngeo642

Forest fires convert a small portion of burning vegetation into charred solid residues such as charcoal. A survey of Scandinavian forest soils reveals that charcoal has a highly patchy distribution, and a shorter-than-expected lifetime.

Full Text - BiogeochemistryFire's black legacy | PDF (248 KB) - BiogeochemistryFire's black legacy

Subject Category: Biogeochemistry

See also: Letter by Ohlson et al.

Seismology: The roller coaster of fault friction - pp676 - 677

Nadia Lapusta

doi:10.1038/ngeo645

During an earthquake, friction is a key control on the initiation, propagation and termination of fault motion. Laboratory experiments that use variable slip rates suggest that friction evolves in a more complex fashion than generally assumed.

Full Text - SeismologyThe roller coaster of fault friction | PDF (114 KB) - SeismologyThe roller coaster of fault friction

Subject Category: Seismology

See also: Letter by Sone & Shimamoto

Atmospheric science: Putting the wind up ozone - pp677 - 679

David S. Stevenson

doi:10.1038/ngeo634

As the Earth warms, the overturning circulation of the upper atmosphere is projected to speed up. Model simulations suggest that this will increase the flux of ozone from the stratosphere to the troposphere, and alter surface levels of ultraviolet radiation.

Full Text - Atmospheric sciencePutting the wind up ozone | PDF (224 KB) - Atmospheric sciencePutting the wind up ozone

Subject Category: Atmospheric science

See also: Letter by Hegglin & Shepherd

Paul G. Silver: Earth deformation, writ large - p679

Sean C. Solomon

doi:10.1038/ngeo650

Full Text - Paul G. SilverEarth deformation, writ large | PDF (149 KB) - Paul G. SilverEarth deformation, writ large

Sinking deltas due to human activities - pp681 - 686

James P. M. Syvitski, Albert J. Kettner, Irina Overeem, Eric W. H. Hutton, Mark T. Hannon, G. Robert Brakenridge, John Day, Charles Vörösmarty, Yoshiki Saito, Liviu Giosan & Robert J. Nicholls

doi:10.1038/ngeo629

Many of the world's deltas are densely populated and intensively farmed. An assessment of recent publications indicates that the majority of these deltas have been subject to intense flooding over the past decade, and that this threat will grow as global sea-level rises and as the deltas subside.

Abstract - | Full Text - Sinking deltas due to human activities | PDF (971 KB) - Sinking deltas due to human activities | Supplementary information

Subject Category: Geomorphology

Large climate-induced changes in ultraviolet index and stratosphere-to-troposphere ozone flux - pp687 - 691

Michaela I. Hegglin & Theodore G. Shepherd

doi:10.1038/ngeo604

Now that stratospheric ozone depletion has been controlled by the Montreal Protocol, interest has turned to the effects of climate change on the ozone layer. An atmospheric chemistry model suggests that climate change will increase the stratosphere-to-troposphere ozone flux by 23% globally between 1965 and 2095, altering the amount of ultraviolet radiation reaching Earth's surface.

First Paragraph - | Full Text - Large climate-induced changes in ultraviolet index and stratosphere-to-troposphere ozone flux | PDF (823 KB) - Large climate-induced changes in ultraviolet index and stratosphere-to-troposphere ozone flux | Supplementary information

Subject Category: Atmospheric science

See also: News and Views by Stevenson

The charcoal carbon pool in boreal forest soils - pp692 - 695

Mikael Ohlson, Barbro Dahlberg, Tonje Økland, Kendrick J. Brown & Rune Halvorsen

doi:10.1038/ngeo617

Forest fires release significant amounts of carbon dioxide into the atmosphere, but also convert a fraction of the burning vegetation to charred black carbon. Examination of 845 soil samples in Scandinavian forests shows that the charcoal content of boreal soils is highly variable, and more susceptible to degradation than has been thought.

First Paragraph - | Full Text - The charcoal carbon pool in boreal forest soils | PDF (687 KB) - The charcoal carbon pool in boreal forest soils | Supplementary information

Subject Category: Biogeochemistry

See also: News and Views by Preston

A microbial source of phosphonates in oligotrophic marine systems - pp696 - 699

Sonya T. Dyhrman, Claudia R. Benitez-Nelson, Elizabeth D. Orchard, Sheean T. Haley & Perry J. Pellechia

doi:10.1038/ngeo639

Phosphonates, compounds with a carbon–phosphorus bond, are a key component of the marine-dissolved organic phosphorus pool. Nuclear magnetic resonance spectroscopy measurements suggest that the cyanobacteria Trichodesmium is a significant source of phosphonates in nutrient-poor regions of the ocean.

First Paragraph - | Full Text - A microbial source of phosphonates in oligotrophic marine systems | PDF (2,084 KB) - A microbial source of phosphonates in oligotrophic marine systems | Supplementary information

Subject Categories: Biogeochemistry | Oceanography

Virtual seismometers in the subsurface of the Earth from seismic interferometry - pp700 - 704

Andrew Curtis, Heather Nicolson, David Halliday, Jeannot Trampert & Brian Baptie

doi:10.1038/ngeo615

Earthquakes often occur in areas that lack an array of seismometers, resulting in a scarcity of local measurements from some regions of great geological interest. In such regions, some earthquakes themselves may be turned into virtual seismometers that are capable of measuring strain caused by passing waves from other earthquakes.

First Paragraph - | Full Text - Virtual seismometers in the subsurface of the Earth from seismic interferometry | PDF (8,363 KB) - Virtual seismometers in the subsurface of the Earth from seismic interferometry | Supplementary information

Subject Category: Seismology

Frictional resistance of faults during accelerating and decelerating earthquake slip - pp705 - 708

Hiroki Sone & Toshihiko Shimamoto

doi:10.1038/ngeo637

The dynamic friction along faults controls earthquake ruptures in the crust, but many previous studies have quantified this value only for constant slip rates. Experiments accounting for the more realistic condition of changing slip rates suggest that faults undergo a sequence of strengthening, weakening and healing during acceleration and deceleration of slip.

First Paragraph - | Full Text - Frictional resistance of faults during accelerating and decelerating earthquake slip | PDF (2,424 KB) - Frictional resistance of faults during accelerating and decelerating earthquake slip | Supplementary information

Subject Categories: Seismology | Structural geology, tectonics and geodynamics

See also: News and Views by Lapusta

Rock pulverization at high strain rate near the San Andreas fault - pp709 - 712

Mai-Linh Doan & Gérard Gary

doi:10.1038/ngeo640

Rocks near the San Andreas fault are pervasively crushed at distances of up to 400 m from its core. Laboratory experiments and calculations suggest that the rocks were pulverized at high strain rates (>150 s^-1) associated with a supershear rupture—a rupture propagating at a velocity equal to greater than that of seismic shear waves.

First Paragraph - | Full Text - Rock pulverization at high strain rate near the San Andreas fault | PDF (1,118 KB) - Rock pulverization at high strain rate near the San Andreas fault | Supplementary information

Subject Categories: Seismology | Structural geology, tectonics and geodynamics

No asymmetry in geomagnetic reversals recorded by 1.1-billion-year-old Keweenawan basalts - pp713 - 717

Nicholas L. Swanson-Hysell, Adam C. Maloof, Benjamin P. Weiss & David A. D. Evans

doi:10.1038/ngeo622

1.1-billion-year-old volcanic rocks in North America are thought to record asymmetric geomagnetic reversals, indicating non-axial dipolar behaviour of the magnetic field. High-resolution data from Ontario suggest that the reversals were instead symmetric, and that the apparent reversal asymmetry is an aliasing effect of the low resolution of earlier samples combined with the rapid motion of North America.

First Paragraph - | Full Text - No asymmetry in geomagnetic reversals recorded by 1.1-billion-year-old Keweenawan basalts | PDF (3,218 KB) - No asymmetry in geomagnetic reversals recorded by 1.1-billion-year-old Keweenawan basalts | Supplementary information

Subject Category: Geomagnetism, palaeomagnetism and core processes

See also: News and Views by Meert

Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake - pp718 - 724

Zheng-Kang Shen, Jianbao Sun, Peizhen Zhang, Yongge Wan, Min Wang, Roland Bürgmann, Yuehua Zeng, Weijun Gan, Hua Liao & Qingliang Wang

doi:10.1038/ngeo636

The devastating Wenchuan earthquake in 2008 struck along a fault zone that showed low rates of deformation. Analysis of GPS and InSAR data suggests that, as structural barriers failed during a single earthquake, the rupture cascaded across multiple fault segments, which may explain the high magnitude of the event.

Abstract - | Full Text - Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake | PDF (3,284 KB) - Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake | Supplementary information

Subject Categories: Seismology | Structural geology, tectonics and geodynamics

See also: related Backstory

The cycling and redox state of nitrogen in the Archaean ocean - pp725 - 729

Linda V. Godfrey & Paul G. Falkowski

doi:10.1038/ngeo633

The initial production of oxygen in early Earth's oceans altered the redox chemistry and cycling of nitrogen. A record of nitrogen isotopes from preserved organic matter indicates nitrogen cycling in the presence of free oxygen 2.67 billion years ago, about 200 million years before the first geochemical evidence for atmospheric free oxygen.

Abstract - | Full Text - The cycling and redox state of nitrogen in the Archaean ocean | PDF (878 KB) - The cycling and redox state of nitrogen in the Archaean ocean | Supplementary information

Subject Categories: Biogeochemistry | Palaeoclimate and palaeoceanography

The influence of climate on the tectonic evolution of mountain belts - p730

Kelin X. Whipple

doi:10.1038/ngeo638

Full Text - The influence of climate on the tectonic evolution of mountain belts | PDF (76 KB) - The influence of climate on the tectonic evolution of mountain belts

Revealing ruptures - p732

doi:10.1038/ngeo641

Abstract - | Full Text - Revealing ruptures | PDF (266 KB) - Revealing ruptures

See also: Article by Shen et al.