Time to act - p483

doi:10.1038/ngeo275

Twice in the month of May 2008 did natural catastrophe strike Asia. Public attention in the wake of destruction offers a chance for better protection in China, Myanmar and elsewhere.

Full Text - Time to act | PDF (190 KB) - Time to act

International trade and climate - p484

Glen P. Peters & Christopher L. Weber

doi:10.1038/ngeo271

Full Text - International trade and climate | PDF (89 KB) - International trade and climate

Topography reveals seismic hazard - pp485 - 487

Eric Kirby, Kelin Whipple & Nathan Harkins

doi:10.1038/ngeo265

The devastating earthquake in the Chinese province of Sichuan struck an area that was not expected to suffer seismic activity of such magnitude. Yet topographic analyses of the region indicate active deformation, suggesting a way of refining maps of earthquake risk elsewhere.

Full Text - Topography reveals seismic hazard | PDF (394 KB) - Topography reveals seismic hazard

Myanmar's deadly daffodil - pp488 - 490

Peter J. Webster

doi:10.1038/ngeo257

Tropical cyclone Nargis wrought havoc in southern Myanmar, with an estimated death toll well above 100,000. Potential future disasters could be alleviated with currently available forecasting skill and effective disaster mitigation plans.

Full Text - Myanmar's deadly daffodil | PDF (576 KB) - Myanmar's deadly daffodil

A coast in decline - p491

Sea Change: Britain's Coastal Catastrophe by Richard Girling

doi:10.1038/ngeo253

Full Text - A coast in decline | PDF (105 KB) - A coast in decline

Forests on Greenland, Titan's atmosphere and more - p492

doi:10.1038/ngeo276

Full Text - Forests on Greenland, Titan's atmosphere and more | PDF (174 KB) - Forests on Greenland, Titan's atmosphere and more

Geomorphology: Avalanches and moraines - pp493 - 494

David J. A. Evans

doi:10.1038/ngeo255

The Waiho Loop moraine in New Zealand's southern Alps had long been viewed as a southern icon of a recent glacier response to cooling climate, possibly the Younger Dryas cold event. But a closer look has implicated a landslide in this particular glacial advance.

Full Text - GeomorphologyAvalanches and moraines | PDF (287 KB) - GeomorphologyAvalanches and moraines

Subject Category: Geomorphology

Environmental science: Arsenic meets dense populations - pp494 - 496

Alexander van Geen

doi:10.1038/ngeo268

In the South Asian lowlands, high population density coincides with dangerous levels of arsenic in groundwater. Maps based on surface geology can help identify regions at risk of arsenic contamination.

Full Text - Environmental scienceArsenic meets dense populations | PDF (613 KB) - Environmental scienceArsenic meets dense populations

Subject Categories: Biogeochemistry | Geomorphology

Climate science: Take the long view - p496

Heike Langenberg

doi:10.1038/ngeo272

Full Text - Climate scienceTake the long view | PDF (161 KB) - Climate scienceTake the long view

Palaeoceanography: Seeing changes in a changing sea - pp497 - 498

Justin B. Ries

doi:10.1038/ngeo273

The ratio of magnesium to calcium in sea water is thought to have influenced the skeletal mineralogy of certain marine calcifiers throughout the Phanerozoic eon. A fresh look at old data suggests that mass extinctions may have also played a role.

Full Text - PalaeoceanographySeeing changes in a changing sea | PDF (277 KB) - PalaeoceanographySeeing changes in a changing sea

Subject Category: Palaeoclimate and palaeoceanography

Volcanology: Molten carbonate eruptions - p498

Ninad Bondre

doi:10.1038/ngeo274

Full Text - VolcanologyMolten carbonate eruptions | PDF (182 KB) - VolcanologyMolten carbonate eruptions

Tectonics: The biggest break-up - pp499 - 500

Christophe Pascal

doi:10.1038/ngeo270

Almost immediately after all the Earth's continents were amalgamated into the supercontinent Pangaea, rifting began to tear it apart. Subduction of the oceanic region of the Pangaean plate beneath its own continental margin may have been the trigger.

Full Text - TectonicsThe biggest break-up | PDF (155 KB) - TectonicsThe biggest break-up

Subject Category: Structural geology, tectonics and geodynamics

Volcanoes: Making calderas from mud - pp500 - 501

Achim J. Kopf

doi:10.1038/ngeo256

Mud volcanoes often exhibit calderas, which are large circular depressions at their summit. Detailed mapping around the Caspian Sea suggests that caldera-forming mud volcanoes are dynamically similar to magmatic volcanoes.

Full Text - VolcanoesMaking calderas from mud | PDF (250 KB) - VolcanoesMaking calderas from mud

Subject Category: Volcanology, mineralogy and petrology

Rejuvenation and erosion of the cratonic lithosphere - pp503 - 510

Stephen F. Foley

doi:10.1038/ngeo261

Cratons are ancient continental nuclei that have resisted significant fragmentation for almost two billion years. Yet, many cratons also experience phases of instability in the form of erosion and rejuvenation of their thick lithospheric mantle keels. Melting governed by redox processes as well as small-scale convection play a key role in triggering such instability.

First Paragraph - Rejuvenation and erosion of the cratonic lithosphere | Full Text - Rejuvenation and erosion of the cratonic lithosphere | PDF (293 KB) - Rejuvenation and erosion of the cratonic lithosphere

Subject Categories: Structural geology, tectonics and geodynamics | Volcanology, mineralogy and petrology

Increase in hourly precipitation extremes beyond expectations from temperature changes - pp511 - 514

Geert Lenderink & Erik van Meijgaard

doi:10.1038/ngeo262

Changes in precipitation extremes under greenhouse warming are commonly assumed to be constrained by the Clausius–Clapeyron relationship, implying an increase in extreme precipitation of 7% per degree of climate warming. An analysis of 99 years of observations along with simulations with a regional climate model show that short-duration precipitation extremes can instead increase in severity twice as fast, by 14% per degree of warming.

First Paragraph - Increase in hourly precipitation extremes beyond expectations from temperature changes | Full Text - Increase in hourly precipitation extremes beyond expectations from temperature changes | PDF (539 KB) - Increase in hourly precipitation extremes beyond expectations from temperature changes | Supplementary information

Subject Categories: Atmospheric science | Climate science | Hydrology, hydrogeology and limnology

See also: Correspondence by Haerter & Berg | Correspondence by Lenderink & van Meijgaard

Monsoons as eddy-mediated regime transitions of the tropical overturning circulation - pp515 - 519

Simona Bordoni & Tapio Schneider

doi:10.1038/ngeo248

Monsoons are often viewed as planetary-scale sea-breeze circulations, caused by contrasts in the thermal properties between oceans and land surfaces. Numerical simulations suggest that instead feedbacks between large-scale extratropical eddies and the tropical atmospheric overturning circulation are essential for the development of monsoons.

First Paragraph - Monsoons as eddy-mediated regime transitions of the tropical overturning circulation | Full Text - Monsoons as eddy-mediated regime transitions of the tropical overturning circulation | PDF (453 KB) - Monsoons as eddy-mediated regime transitions of the tropical overturning circulation

Subject Category: Atmospheric science

An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period - pp520 - 523

Achim Brauer, Gerald H. Haug, Peter Dulski, Daniel M. Sigman & Jörg F. W. Negendank

doi:10.1038/ngeo263

The Younger Dryas cold reversal during the last glacial termination is one of the most abrupt climate change events observed in the Northern Hemisphere. Analyses of varved lake sediments from western Germany suggest that storminess in the North Atlantic region increased within a single year at this time, providing a mechanistic link between a decrease in the meridional overturning circulation and western European cooling.

First Paragraph - An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period | Full Text - An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period | PDF (1,023 KB) - An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period | Supplementary information

Evidence for a landslide origin of New Zealand's Waiho Loop moraine - pp524 - 526

D. Santamaria Tovar, J. Shulmeister & T. R. Davies

doi:10.1038/ngeo249

The Waiho Loop Moraine has been interpreted as evidence for Younger Dryas cooling in southern New Zealand, but recent dating and climatological studies have questioned this idea. A detailed analysis of the sedimentology of the moraine suggests it was formed after a large landslide onto the Franz Josef glacier triggered a glacial surge, independent of climate forcing.

First Paragraph - Evidence for a landslide origin of New Zealand/'s Waiho Loop moraine | Full Text - Evidence for a landslide origin of New Zealand's Waiho Loop moraine | PDF (1,496 KB) - Evidence for a landslide origin of New Zealand's Waiho Loop moraine | Supplementary information

Subject Category: Palaeoclimate and palaeoceanography

See also: related Backstory | News and Views by Evans

Phanerozoic trends in skeletal mineralogy driven by mass extinctions - pp527 - 530

Wolfgang Kiessling, Martin Aberhan & Loïc Villier

doi:10.1038/ngeo251

Changes in ocean chemistry that favoured the precipitation of aragonite or calcite are thought to have influenced the skeletal mineralogy of marine calcifyers. An investigation of the original skeletal mineralogy of large numbers of marine taxa suggests that the selective recovery of marine organisms from mass extinctions has a much greater influence on the overall percentage of aragonitic organisms than the Mg/Ca ratio of the oceans.

First Paragraph - Phanerozoic trends in skeletal mineralogy driven by mass extinctions | Full Text - Phanerozoic trends in skeletal mineralogy driven by mass extinctions | PDF (271 KB) - Phanerozoic trends in skeletal mineralogy driven by mass extinctions | Supplementary information

Subject Categories: Biogeochemistry | Palaeontology

See also: News and Views by Ries

Collapse at the eastern Eiger flank in the Swiss Alps - pp531 - 535

Thierry Oppikofer, Michel Jaboyedoff & Hans-Rudolf Keusen

doi:10.1038/ngeo258

On 13 June 2006, parts of the eastern flank of the Eiger peak in the Swiss Alps collapsed, leading to a major rock fall. The unstable spur on this flank is made up of several blocks that move relative to one another. Instability was initiated by a block at the rear that acted as a wedge and triggered motion of the other blocks.

First Paragraph - Collapse at the eastern Eiger flank in the Swiss Alps | Full Text - Collapse at the eastern Eiger flank in the Swiss Alps | PDF (2,042 KB) - Collapse at the eastern Eiger flank in the Swiss Alps | Supplementary information

Subject Categories: Geomorphology | Structural geology, tectonics and geodynamics

See also: related Backstory

Predicting groundwater arsenic contamination in Southeast Asia from surface parameters - pp536 - 542

Lenny Winkel, Michael Berg, Manouchehr Amini, Stephan J. Hug & C. Annette Johnson

doi:10.1038/ngeo254

Arsenic contamination of groundwater resources threatens the health of millions of people worldwide, particularly in the densely populated river deltas of Southeast Asia. Maps of areas at risk of groundwater arsenic concentrations have been produced by combining geological and surface-soil parameters in a logistic regression model. They show that Holocene deltaic and organic-rich surface sediments are key indicators for arsenic risk areas and indicate elevated risks in Sumatra and Myanmar where no groundwater studies exist.

Abstract - Predicting groundwater arsenic contamination in Southeast Asia from surface parameters | Full Text - Predicting groundwater arsenic contamination in Southeast Asia from surface parameters | PDF (1,164 KB) - Predicting groundwater arsenic contamination in Southeast Asia from surface parameters | Supplementary information

See also: related Backstory | News and Views by van Geen

Mechanisms for retention of bioavailable nitrogen in volcanic rainforest soils - pp543 - 548

Dries Huygens, Pascal Boeckx, Pamela Templer, Leandro Paulino, Oswald Van Cleemput, Carlos Oyarzún, Christoph Müller & Roberto Godoy

doi:10.1038/ngeo252

Pristine temperate rainforests are known to produce large amounts of bioavailable nitrogen, with only minimal loss. Tracing ¹⁵N in volcanic soils of a temperate evergreen rainforest in southern Chile helps to further unravel the retention mechanisms for bioavailable nitrogen in these ecosystems.

Abstract - Mechanisms for retention of bioavailable nitrogen in volcanic rainforest soils | Full Text - Mechanisms for retention of bioavailable nitrogen in volcanic rainforest soils | PDF (285 KB) - Mechanisms for retention of bioavailable nitrogen in volcanic rainforest soils | Supplementary information

Subject Categories: Biogeochemistry | Ecology

Self-subduction of the Pangaean global plate - pp549 - 553

Gabriel Gutiérrez-Alonso, Javier Fernández-Suárez, Arlo B. Weil, J. Brendan Murphy, R. Damian Nance, Fernando Corfú & Stephen T. Johnston

doi:10.1038/ngeo250

The Earth's continents amalgamated into the supercontinent Pangaea 320 million years ago. After the supercontinent formed, structural deformation continued, which eventually resulted in the subduction of the ocean margin of Pangaea beneath the continental edge at the other end of the same plate.

Abstract - Self-subduction of the Pangaean global plate | Full Text - Self-subduction of the Pangaean global plate | PDF (340 KB) - Self-subduction of the Pangaean global plate

Subject Category: Structural geology, tectonics and geodynamics

See also: News and Views by Pascal

Formation of supercontinents linked to increases in atmospheric oxygen - pp554 - 558

Ian H. Campbell & Charlotte M. Allen

doi:10.1038/ngeo259

Atmospheric oxygen levels on Earth rose in at least six distinct steps and an examination of the timing of the steps suggests that they coincided with the formation of supercontinents and supermountains. This leads to the hypothesis that increased erosion of these supermountains released large amounts of nutrients to the oceans, stimulating productivity and the release of oxygen to the atmosphere. The subsequent burial of organic carbon along with the mountain sediments would have sustained the increased oxygen levels.

Abstract - Formation of supercontinents linked to increases in atmospheric oxygen | Full Text - Formation of supercontinents linked to increases in atmospheric oxygen | PDF (242 KB) - Formation of supercontinents linked to increases in atmospheric oxygen | Supplementary information

Subject Categories: Atmospheric science | Biogeochemistry

The moraine event - p562

doi:10.1038/ngeo267

Dan Santamaria Tovar, along with advisor Jamie Shulmeister and colleagues, hiked, kayaked and mountain-biked their way through dense New Zealand rainforest in search of the origins of the Waiho Loop moraine.

Full Text - The moraine event | PDF (191 KB) - The moraine event

All hands to the pump - pE12

doi:10.1038/ngeo266

Lenny Winkel and colleagues found that strong arm muscles can be required to test South Sumatran groundwater samples for arsenic content.

Full Text - All hands to the pump | PDF (233 KB) - All hands to the pump

Tracking Alpine rockfalls - pE13

doi:10.1038/ngeo269

Balancing their instruments on precarious cliff faces and braving intense media and public attention, Thierry Oppikofer and colleagues monitored the evolution of a rockslide along the eastern flank of the Eiger peak in the Swiss Alps.

Full Text - Tracking Alpine rockfalls | PDF (242 KB) - Tracking Alpine rockfalls