Research articles

Arc-shaped scours, sandwaves and channels on the Hudson Bay seafloor suggest that the catastrophic drainage of lake Agassiz–Ojibway occurred as a subglacial flood beneath the Laurentide Ice Sheet, which covered northern North America.

A large lens-shaped feature bounded by shear zones characterizes the remnant slab beneath the Hindu Kush region. Rather than dripping by viscous flow, the slab is actively stretching and might eventually break off before descending further into the underlying mantle.

Long linear ridges in the Valles Marineris region of Mars most likely represent fault zones that have been cemented by water-deposited minerals. This implies that water in the Martian crust could have traversed long distances via faults and fractures.

Dust input to alpine lakes in the western United States has risen dramatically following westward expansion of human settlements and increased livestock grazing over the past two centuries. The increased dust flux deposits additional nutrients and minerals to the lakes, with important implications for water chemistry, productivity and nutrient cycling.

Over the last twenty years, changes in the shoreline between the Amazon and Orinoco rivers have largely been controlled by the 18.6 year tidal cycle. By 2015 AD, the tidal cycle will account for 90 metres of shoreline retreat in French Guiana and 6 centimetres of sea level rise.

Extensive damage to coastal Louisiana from Hurricane Katrina in 2005 was largely attributed to high rates of relative sea-level rise caused by coastal subsidence. An examination of the underlying Holocene sediments shows that the compaction of peat-rich deposits contributes significantly to Mississippi Delta subsidence rates of up to 5 mm per year.

Eddy activity in the North Atlantic ocean produces fluctuations in ocean-wide volume transport on the order of 20×10⁶ cubic metres per second, on multi-year timescales. Such background noise makes it impossible to detect possible trends in the ocean circulation due to a changing climate without multi-decadal observations in three spatial dimensions.

The Columbia River Basalt Group in the northwestern United States, derived from flood basalt eruptions that occurred 16 million years ago, exhibits variability in geography and trace element geochemistry that has led to a number of proposed magma origins. However, the geochemical variability can be explained by a relatively simple model in which magma is derived from a mantle plume that assimilated continental crust in a centralized magma system.

Viscous relaxation, rather than afterslip, most likely dominated ground deformation after two large earthquakes in Iceland. This suggests that afterslip may play a relatively less important role in immature fault zones as compared with more mature ones such as the San Andreas fault.

Nanoscale evidence suggests that the Tumbiana Formation stromatolites in Australia were influenced by microbial activity. In the stromatolites, clusters of organic globules are closely associated with 2,724-million-year-old aragonite crystals.

The occurrence of lower-hybrid solitary structures in the ionoshere are triggered by lightning-induced whistlers, revealing a new coupling process between the troposphere and the ionosphere.

It may be possible to predict eruptions of the Piton de la Fournaise volcano by continuously monitoring changes at depth using very small fluctuations in the ambient seismic noise. The changes are probably related to inflation caused by movement of magma at depth.

A strong radar reflection in the West Antarctic ice sheet is related to the eruption of the newly identified Hudson Mountains Subglacial Volcano dated to 207 BC. This eruption probably caused short term changes in regional glacial and meltwater flow.

A significant fraction of the anthropogenic nitrogen input into the coastal oceans from fertilizers is transferred back to land by commercial fisheries.

The final geometry of an impact crater can be significantly influenced by the geological and geomorphological structure of the impact site; therefore, it may not on its own provide accurate information regarding the direction and angle of impact.

Observed estimates of ice losses in Antarctica combined with regional modelling of ice accumulation in the interior suggest that East Antarctica is close to a balanced mass budget, but large losses of ice occur in the narrow outlet channels of West Antarctic glaciers and at the northern tip of the Antarctic peninsula.