GeoLog

Regular Features

Imaggeo on Mondays: Stirring up a sandstorm

These are the outwash plains for the Icelandic volcano, Katla: An outwash plain (or sandur) is a broad, shallowly sloping region ahead of a glacial front. They are made up of material that has been deposited by glacial meltwater, released either by geothermal heating or a subglacial eruption. The extensive volcanism and abundance of ice-capped volcanoes in southern Iceland means that the outwash p ...[Read More]

Imaggeo on Mondays: Metamorphosis

This fold is part of the metamorphic core of the Pyrenees. The shear zone is almost vertical, producing a small parasitic fold (a smaller fold within a larger one), which looks almost as if it continues into the sky. The metamorphic sediments are about 500 million years old and have been deformed several times, most recently during the alpine orogeny. The alpine orogeny was period of extensive mou ...[Read More]

Imaggeo on Mondays: A fractured relationship – when lava meets ice

The Kuril Island Chain is formed by four active volcanoes: Golovnin, Mendeleev, Tyatya and Smirnov. Stolbchaty Cape, where the Okhotsk Sea meets the coast of Kunashir Island, is not far from Mendeleev Volcano – responsible for the many hot springs in the area. These are fed by seawater and heated as the water comes into contact with magma and hot rocks within the mantle. The picture shows an outcr ...[Read More]

Sussing out sea level rise

Ocean thermal expansion, that is, the increase in water volume due to temperature alone, is relatively well understood – as is the retreat of both mountain glaciers and ice caps. While most models simulate these effectively, there is little understanding of how both the Greenland and Antarctic ice sheets will respond to climate change. This is because the full extent of ice-ocean interactions is n ...[Read More]