At 0.4km2 (40 ha) and up to 75m deep Pitch Lake is the largest natural surface deposit of asphalt in the world. Located at La Brea, southwest Trinidad, Pitch Lake is mined for asphalt by Lake Asphalt of Trinidad and Tobago as well as attracting around 20,000 tourists to the site each year.

Pitch Lake is believed by geologists to sit at the intersection of two faults linked with regional subduction under the Caribbean Plate. Oil from a deep deposit is forced upwards along the faults to the surface; lighter oil molecules evaporate leaving behind the thicker, heavier molecules such as bitumen.

Interestingly this place isn’t void of life, researchers have identified an active extremophile microbiological ecosystem, which grow on the available asphaltenes as a sole carbon energy source.

-Matt J

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The Gachala emerald

Most large gem quality crystals end up being cut into faceted gems for jewellery, so it is rare for such a beauty as this to be rescued for the delectation of the public. One of the treasures of the Smithsonian was spared the usual fate for such wonders of nature, and donated to the museum by the jeweller Harry Winston (who also donated the Hope diamond).

Originally mined in Colombia in 1967, it is named after the mining area whence it came. Unlike the more traditional mining areas such as Muzo or Chivor, Gachala was not exploited by the traditional peoples of the area before the conquest, but was only discovered in the mid 1950’s. The crystal is reputed to be one of the finest on display in the world. The colour is a lovely deep summer grass green, and it weighs in at a whopping 172 grams (858 carats) for a size of 5x5cm. Emeralds from this area some 100km east of Bogota are often a lighter green, but they tend to contain smaller ‘gardens’ of inclusions within. 


Image credit: Andrew Bossi

Is the world finally embracing renewable energy?

We hear an awful lot of bad news regarding climate change and governments’ latent reaction to this ongoing global issue. However, one expert, Professor Catherine Mitchell from the University of Exeter, now reckons that there has been a global shift in attitude, policy, flexibility, efficiency, investment and efforts towards renewable energy sources such as wind, ocean, and solar, while there has been a decline in fossil fuel investment. In fact, she argues that renewable energy investment has, for the first time, outstripped investment in “dirty fuels”. This is due to a number of reasons, mainly evidence informed policy on the importance of adaption and mitigation to climate change on regional, national and global levels. It is also becoming clearer that renewable energy system costs are lowering as social preference increases, all while improving energy security and greatly helping to meet carbon reduction targets. While Professor Mitchell is careful to stress that climate change is an ongoing, complex issue with firm action required behind policy, there seems to be cause for optimism. As the momentum for favouring renewable energy systems over older, conventional systems becomes the norm, is there hope that the world is finally acting on a problem recognised decades ago?