The oldest bit of the Earth

Many of you will have heard me discuss in class that when I was a student (which isn't that long ago!) I learnt that the oldest rock in the crust was 3,800 Ma from Greenland; this had changed to 4.200 Ma from dating a rock in northern Canada.  We now have to revise that number again as a Zircon crystal from Western Australia has been dated (by the Uranium-Lead method) to be 4,400 Ma.  We still have meteorites that are older, but we are finding fragments of the earliest crust which may give us an indication of the processes that formed our planet.

The Paradox of Plenty

It is a hidden secret of our increasing desire for and use of electronic gadgets that many of the minerals essential to their manufacture are both the product of, and the finance for, war.  

Mineral resources are distributed by geological accident rather than geopolitical convenience.  This can create the potential for enormous geological wealth in places that do not have the political and financial stability for their exploitation to benefit the communities in which they are located the 'Resource Curse'.  You may be familiar with the concept of 'Blood Diamonds' from the film, but less well known is how gold, tin, tungsten and coltan can also be produced in situations of conflict and terrorism.

Apple produce an annual report to detail the source of the mineral resources that go into their iPhones, iPads and Macs showing how many of their suppliers meet international standards of human rights and environmental protection.  It makes for interesting reading and it does how the importance of geological exploration to locate the resources we need in a wider variety of places.  Do you think about where the minerals in your gadgets started out as rocks in the ground?

The end of the rainbow?

The luck of the Irish may have struck!  Geologists working for the Geological Survey of Ireland and the Geological Survey of Northern Ireland have identified a gold deposit that may be worth £11,000,000,000.  The potential is huge, but so are the costs.  Should the Irish develop this resource and help to pay their debts?

A Green land?

Greenland is a strange place.  It has a population a little bit bigger than the population of Barry in an area over 100 times greater than that of Wales.  It is still linked to Denmark, relying on a large financial subsidy from the Danish government to pay for essential services which is being reduced as Greenland gradually becomes more independent.  This does mean that the Greenlanders will need an alternative source of income to replace the £378,345,000 that the Danes give each year (£6,712 for every Greenlander).

The only way that such a small population with such an inhospitable climate is going to make that amount of money is to exploit its natural resources.  This creates a huge dilemma for the people who live there.  Geologists from an Australian mining company, Tanbreez, have found a potentially huge deposit of rare earth minerals but the people who live around the site are conflicted.  The money and the jobs that the mine will bring will resolve many of the economic and social problems that remote communites suffer, however new social and environmental problems will be caused.

Do you think it's possible to balance the positive and negative impacts of this development?  The geology of Greenland means that there are plenty of geological resources in the rocks, this could be the first step in a long period of economic growth or the start of the destruction of communities.  

There is an alternative view of these resources here.

A new source of energy

The American Geophysical Union conference continues to throw up exciting developments in geological research including the possibility of extracting hydrogen from olivine.  By speeding up the natural geochemical process of serpentinisation hydrogen can be liberated from olivine crystals giving a potential source of carbon-free energy.

All you need is a pressure cooker (to give a pressure 2,000 times that of the atmosphere and a few hundred degrees of heat) made with some diamonds and some ruby to speed up the reaction and you can make your own hydrogen.

This could make Iceland rich again.  Can you work out why?

Penetration twin

A penetration twin is a type of twinned crystal.  This is where crystals are joined either as contact twins, where the crystals share one surface, or as a penetration twin,where the crystals grow across each other (as in the crystal shown above).

Twinning is a feature of several minerals and can be a characteristic feature of different types of feldspar (see below).  The crystal above is a mineral that you should know; can you identify it?

An expensive piece of rock

A rare pink diamond has sold for £52,000,000 which, it has to be said, is quite a lot of money for soething that started out its existence as organic material on the sea bed.  A trip down a subduction zone and back again via a volcano turned some carbon into an object that is worth the price of 2 new schools or would pay over 1,600 teachers for a year.

Looking at the specimen close up shows that it is flawless and vivid pink in colour.  Perhaps that explain why someone would pay £4,362,416.11 per gramme, over 170,000 times more than gold.

Money grows on trees

Well almost....

Research on Eucalyptus trees in Australia has shown that the trees' leaves can contain a very small trace amount of gold if there is gold in the rocks below.  This isn't enough to extract useful quantities of the metal from the tree; far more usefully it can indicate the presence of gold in the rocks which may be worth investigating.  This gives geologists another tool with which to find resources, particularly ones lile gold that are found in such low concentrations.

It has been known for a long time that particular plants can indicate the geology under the surface, but this is the first time that these elements have been able to be located in the living tissue of the plants.

Thanks to Rosie for spotting this story.

Diamonds are forever?

As some of you know, I really don't like diamonds.  There are several reasons for this that I would be happy to share with anyone that asks me; but it seems that I am not alone in this.  The price of rubies and sapphires has increased more quickly than the price of diamonds over the last few years  indicating a rise in the demand for these precious gemstones.

Ruby and Sapphire are both varieties of a mineral largely made up of aluminium oxide called Corundum.  The different colours are caused by different trace elements of Chromium (which gives ruby its red colour) and Iron, Titanium, Magnesium or Copper (which give Sapphires their colour varieties).

Perhaps this change in demand is caused by fashion or by increasing numbers of women choosing their own jewellery (men tend to go for the "safe" option of diamond if they are choosing).  Regardless of the reason, the increasing price will lead to more geological exploration to discover new sources of these minerals.

BBC News story

In case you are wondering, my favourite decorative mineral has to be one that has a relatively low price (though it is useful as an ore of copper) but is beautiful with its botryoidal, banded shade of green. Can you find out what it is?