GeoLog

Geochemistry, Mineralogy, Petrology & Volcanology

Imaggeo on Mondays: Marble outcrops

This week’s Imaggeo on Mondays image was taken by Prof. Konstantinos Kourtidis, in Alykes, along the southern coast of Thassos island, where he photographed the beautifully white marbles that outcrop along the coastline. The Greek Island of Thassos is located in northeastern Greece, close to the coast of Thrace in the Aegean Sea, although geographically it belongs to the Macedonia region. There is ...[Read More]

The known unknowns – the outstanding 49 questions in Earth Sciences (Part II)

Here is the second instalment in our series covering the biggest unknowns in the Geosciences. Last week we explored what it is about the Earth’s origin that still remains unclear and this week we probe the Earth’s deep interior. Unlike in Jules Verne’s Journey to the Centre of the Earth, there are no volcanic tubes we can climb down which will allow us to discover the inner workings of our Planet. ...[Read More]

Imaggeo on Mondays: Spectacular splatter – the marvels of a mud volcano

Mud volcanoes, unlike many others, do not extrude lava. Instead, they release glutinous bubbling brown slurry of mineral-rich water and sediment. They range in size from several kilometres across, to less than a metre – the little ones are known as mud pots, reflecting their diminutive nature. The world’s largest, though, is Lusi: a mud volcano in East Java that released an astonishing 180,000 cub ...[Read More]

Geosciences Column: The Toba eruption probably did have a global effect after all

Almost everyone has heard of the Toba super-eruption, which took place on the island of Sumatra roughly 74,000 years ago, but the only evidence of tephra or tuff (volcanic fragments) from the eruption is in Asia, with nothing definite further afield. It has sometimes been thought that this huge eruption may have led to a volcanic winter, a period of at least several years of low temperatures follo ...[Read More]