Most geological collections we hear about in the news are the prettiest, oldest, youngest, largest, smallest, rarest, most expensive or have some exciting story related to them that ties them to the evolution of our planet. Dinosaurs, human remains and meteorites are particularly popular. Over the last year we’ve embarked on a major curatorial project rehousing something that is the opposite – an unglamorous collection of bags of crushed rock.
CoG3 project member and University of Manchester PhD student Sulaiman Mulroy reports back on a recent fieldwork trip to Cameroon in West Africa.
In June 2016 I travelled to Cameroon to collect samples from the Nkamouna laterite, one of a number of lateritic ore deposits formed on top of lenticular serpentinite rocks, which cover around 240km2 in the East of Cameroon.
In total the region hosts seven lateritic ore bodies, covering ~1250km2, though only two have been subjected to rigorous exploration: Nkamouna has proven and probable reserves of 54Mt at grades of 0.25% Co and 1.7% Ni, and further north, at Mada, 150Mt of inferred resources of similar grade are believed to be hosted in the laterite.
by Chris Hughes, Earth Sciences, Natural History Museum
Every year in early May the Museum participates in the Fossil Festival at Lyme Regis, on the Jurassic Coast in Dorset. It’s an event involving thousands of members of the public with an interest in the ancient marine fossils found in the rocks along the coast near Lyme. Museum scientists occupy a large marquee on the sea front and engage in a whole range of outreach activities. The idea is to enable everybody to meet scientists, to talk about real fossils and enjoy exploring the geology and natural history of this area.
We headed down to Lyme Regis on the Tuesday before the Fossil Festival commenced. This allowed us a day to carry out some fieldwork in this world famous fossil locality before we led an outreach event at the Thomas Hardye School, in Dorset. On our field visit we had a look at some of the great fossil sites that are found all around Lyme. We decided to head out west toward the famous ammonite pavement at Monmouth beach. This was my first time in Lyme Regis and I was very excited because I had been told that these rocks were some of the best in the world for these fossils.
Some meteorites, called CI chondrites, contain quite a lot of water; more than 15% of their total weight. Scientists have suggested that impacts by meteorites like these could have delivered water to the early Earth. The water in CI chondrites is locked up in minerals produced by aqueous alteration processes on the meteorite’s parent asteroid, billions of years ago. It has been very hard to study these minerals due to their small size, but new work carried out by the Meteorite Group at the Natural History Museum has been able to quantify the abundance of these minerals.
The minerals produced by aqueous alteration (including phyllosilicates, carbonates, sulphides and oxides) are typically less than one micron in size (the width of a human hair is around 100 microns!). They are very important, despite their small size, because they are major carriers of water in meteorites. We need to know how much of a meteorite is made of these minerals in order to fully understand fundamental things such as the physical and chemical conditions of aqueous alteration, and what the original starting mineralogy of asteroids was like.