Extinction of the mammoth and the Clathrate Gun

Joanne Ballard and André Bijkerk (USA) In this article, we will argue that the extinction of megafauna on the mammoth steppes of the Northern Hemisphere may ultimately have been caused by the release of massive quantities of methane in the North Atlantic Ocean at the Amazon Fan near the Brazilian coast and also from the Ormen Lange gas field off the coast of Norway. We will suggest that these events caused significant changes in the flow of water at the surface of the ocean that, in turn, led to very rapid changes in the levels of rainfall. Scientists have already … Read More

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Giant’s Causeway (Part 1): An introduction

Dr Trevor Watts (UK) This is the first of two articles on the volcanicity of the Giant’s Causeway and the surrounding area. The Causeway itself is an area of basalt columns, about 100m or so across, jutting into the Irish Sea. A remnant of a vast ancient lava flow, it is located in a coastal strip that is lavishly scattered with other superb volcanic features. The whole area is both beautiful and fascinating, and neither spoilt in any way, nor over-crowded out of season. We (my wife Chris and I) went there because I had a few days’ work in … Read More

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Warming medieval climate supports a revolution in agriculture

Steven Wade Veatch and Cheryl Bibeau (USA) In the light of our current worries about climate change and global warming, this is the first a series of articles for Deposits that covers significant climate changes that have occurred in the geological past and times when the earth’s climate was hugely different from what we know today. However, this first one covers a slightly more recent event – the Medieval Warm period. The twenty-first century has had some of the hottest temperatures on record, but there was another period that was just as warm or warmer. The Medieval Warm Period (approximately … Read More

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Geology of East Greenland

James Cresswell (UK) Eighty percent of Greenland is covered by ice and, in places, this is up to 3.4km thick. So, Greenland might not immediately spring to mind as a place to go to observe rocks. However, it is a huge country and the ice-free area, at 410,000km2, is nearly twice the size of the UK. This is generally sparsely vegetated, leaving the rocks beautifully exposed and the geology incredibly easy to see. The area of East Greenland around Scoresby Sund, Kong Oscar and Kejser Franz Joseph Fjords is the largest ice-free area in Greenland. It also has incredible geodiversity, … Read More

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