Shining white ammonites: remarkably preserved ammonites from the Posidonia Shales of Southern Germany

Stephen Lautenschlager (Germany) The Lower Jurassic Posidonia Shale Formation of Southern Germany belongs to one of the most famous fossil lagerstätten in the world. Its sediments – finely laminated marly claystones – were deposited in a shallow, inland (epicontinental) sea, the Tethys Ocean, under tropical conditions. The dark grey colour … Read More

Krakatau – Part 2

Dr G Trevor Watts In the fisrt part of this article (Kratatau – Part 1), I started to describe the geology of this famous volcano and also my visit to it. I now continue and you find me on fresh scoria and sulphurous steaming rock, standing on the rim of … Read More

Cerro Negro

Dr G Trevor Watts (UK) Cerro Negro (The Black Hill) is a stark, lively little volcano. Little known outside Nicaragua, it is easily accessible from the city of Léon and well worth the effort of the hike of about a thousand feet up. Location Cerro Negro is about 30km east-north-east … Read More

Amber deposits of the Dominican Republic’s northern cordillera

George Burden (Canada) The rickety taxi bumped and rattled its way southward, into the scenic peaks of the Dominican Republic’s northern cordillera. Frequent washouts from seasonal torrential rains make the going tricky and, at times, even a little perilous. However, we finally arrived at a small community, the site of … Read More

Book review: A Geological Field Guide to the Himalaya in India, Nepal, Bhutan and Tibet, by Dr Daniel Clark-Lowes

This book has something of an aspirational, rather than practical, feel to it. However, there is no doubt – in my mind anyway – that it is the best book on the geology of the Himalaya I have read. It is written with a nice light touch, with some humour. And it covers far more than just geology – where appropriate, it includes history, especially about the exploration of the subcontinent, and Asian culture.

Mineral focus: rutile

Rutile is a metallic-grey to earthy-red, brown, violet or black mineral, largely composed of titanium dioxide (TiO2). It is the most naturally occurring form of this particle and has among the highest refractive indices of any known mineral. It also has a hardness rating of 5.5 to 6.5. Apart from … Read More

Book review: Alderney and La Hague: an Excursion Guide, by Dave Went

I never realised just how diverse the rocks of this – the smallest of the Channel Islands – is. They are clearly well exposed and easily seen along the coast (and the cliffs are wonderful to look at). The guide also points out that the island’s rocks provide the best opportunity to see intrusive, igneous suites of the Cadomian orogeny (a tectonic event or series of events in the late Neoproterozoic, about 650 to 550 million years ago),and the lower Cambrian fluvial strata associated with post-Cadomian sedimentation. And I know from personal experience that each of the walks will be a delight, as the island is phenomenally beautiful.

Book review: The Lewisian: Britain’s oldest rocks, by Graham Park

Recently, I have finished the Great Silurian Controversy, a magnificent book about the nineteenth century arguments over the age of the lower Palaeozoic greywackes/sediments of Devon, and the creation of the concept of the Devonian. And reading The Lewisian: Britain’s oldest rocks by Graham Park, perhaps it occurs to me that this should perhaps be called, The Great Lewisian Controversy. It shares the same historical and scientific intentions, and the same grand sweep of scientific history from the early twentieth century, namely, the exploration over decades of the geology of the Lewisian of northwest Scotland.

Mineral Focus: Kaolinite

Kaolinite is a clay mineral, first described in 1867 for its occurrence in the Jari River basin, Brazil. It is very common and is extensively mined in the UK, France, Brazil, Australia, India, Korea, USA and China. The mineral is mined under the name of Kaolin, but is more commonly … Read More

Book review: Geopedia: A Brief Compendium of Geologic curiosities, by Marcia Bjornerud (with illustrations by Haley Hagerman)

This is a charming little book, which describes itself as an “admittedly idiosyncratic compendium of [geological] words and phrases chosen because they are portals into larger stories”. It succeeds brilliantly at its professed goal, combining a great deal of information, education, and a gentle sense of fun, brought out very nicely by some attractive and humorous illustrations.