Volume 8 Issue 6, June 2015

Nature Geoscience introduces 3,000-word Methods sections that are integrated with the online paper.

Natural landscapes are shaped by frequent moderate-sized events, except for the rare catastrophe. Human modifications to the Earth's surface are, compared with natural processes, increasingly catastrophic.

Global surface warming has slowed since the start of the twenty-first century, while Pacific heat uptake was enhanced. Analyses of ocean heat content suggest that the warm water was transferred to the Indian Ocean, through the Indonesian straits.

It is intuitive, but evidence that high levels of precipitation increase erosion rates has been elusive. The ages of exposed porphyry copper deposits reveal that rocks emplaced at depth travel to the surface faster where precipitation rates are high.

Fjords account for less than 0.1% of the surface of Earth's oceans. A global assessment finds that organic carbon is buried in fjords five times faster than other marine systems, accounting for 11% of global marine organic carbon burial.

The Indian Plate moved north unusually quickly during the late Cretaceous. Numerical simulations suggest that this rapid migration was caused by the pull of two coupled, narrowing subduction zones.

An ancient carbon release resulted in widespread dissolution of carbonates at the sea floor. Numerical simulations suggest that the pattern of dissolution can be explained by a top-down invasion of corrosive bottom waters from the North Atlantic.

The Earth's long-term silica cycle is intimately linked to weathering rates and biogenic uptake. Changes in weathering rates and the retention of silica on land have altered silica availability in the oceans for hundreds of millions of years.

The atmospheric layer that lies above Earth's weather systems can exert a strong downward influence. A review of this influence on storm tracks and surface weather suggests that the dynamical links between the layers hold across timescales.

Nutrient limitation of plant growth can reduce net plant productivity. Model projections indicate that productivity declines when nitrogen and phosphorus limitations are considered, turning terrestrial ecosystems into a net source of CO₂ by 2100.

The slow surface warming since 1998 has been linked to high ocean heat uptake. An analysis of observations and ocean model simulations suggests that the increase in Pacific heat uptake has been compensated by heat transport to the Indian Ocean.

Fjords have been hypothesized to be hotspots of organic carbon burial. A global compilation of organic carbon data and sedimentation rates shows that fjords sequester twice as much carbon as other ocean regions.

Organic matter’s molecular structure has been thought to influence its decomposition. Analyses of dissolved organic carbon in Swedish lakes found that aliphatic and N-containing compounds persisted, while oxidized aromatic compounds were lost.

The Palaeocene–Eocene Thermal Maximum was associated with warming and seafloor carbonate dissolution. Numerical simulations suggest that the spread of deep corrosive water from the North Atlantic can explain the observed dissolution patterns.

Porphyry copper deposits are emplaced at a fixed crustal depth in convergent tectonic settings. The age and distribution of deposits exposed at the surface suggest that mountain exhumation is influenced by precipitation rates.

Deeper ocean waters were anoxic during the Neoproterozoic. Geochemical data suggest a transition from sulphidic to iron-rich mid-depth waters about one billion years ago, coincident with increased iron influx from the supercontinent Rodinia.

Some subduction zones experience earthquake supercycles. Numerical simulations show that successive megathrust earthquakes may load neighbouring parts of the fault, causing it to eventually fail in a giant earthquake that completes a supercycle.

Prior to collision with Eurasia, the Indian Plate rapidly accelerated northwards. Numerical simulations show that the combined pull of two slabs in two parallel, north-dipping subduction systems could have caused this pulse of rapid movement.

Tectonic plate and lower-mantle motions are often considered independent. Plate tectonic reconstructions reveal long-lived interactions between mantle plumes and mid-ocean ridges that imply feedback between plate boundaries and the deep mantle.

Faults weaken during earthquakes. Laboratory simulations of earthquake rupture show that the nanometric-scale fault gouge created during slip is inherently weak and flows by grain-boundary sliding, providing a mechanism to weaken faults.