The Earth Story

Scorodite A common iron arsenate mineral (ie it is poisonous so treat specimens with care), it is named from the Greek word for garlic, since it emits a scent when heated that brings this bulb to mind. It forms in hydrothermal veins precipitating from hot fluids. Locations include Namibia (including the Tsumeb mine from which this piece hails, see http://on.fb.me/1c2CjkD for a more detailed insight into this Mecca of mineral collectors), Germany, the UK and many others. Colours vary from a variety of greens or blues to brown. This lovely piece measures 8x5x3cm and displays a rare and vibrant blue hue. The matrix is made of the complex polymetallic mineral beudantite. Loz Image credit: Rob Lavinsky/iRocks.com http://www.mindat.org/min-3595.html http://bit.ly/1f9jeyt http://bit.ly/1KiNDTG

Blue Dragon Lava The Craters of the Moon volcanic field in Idaho represents large outpourings of basaltic lava formed between 16000 and 2000 years ago. The full field covers an area the size of the state of Rhode Island; this is a tiny fragment of one of those lava flows, the Blue Dragon lava flow.

Iron If you came upon this rock in some random field (without the pen for scale obviously), would you think there was anything special about it? Looks like just about any other rock, right? A bit of pitting on the surface, a bit reddish, has been exposed to the elements and to water, but seems pretty ordinary.

Dales Gorge Formation These redbeds are found in Western Australia near the northwestern corner of that continent, in the Pilbara region near the iron mining community of Pannawonica. They are all part of the Dales Gorge formation, one of the major sources of iron for mining in Australia and one of the classic Banded Iron Formations associated with the rise of oxygen on the planet.

Painting This photograph captures “Artist’s Palette” in Death Valley National Park in just about the right light to illuminate the features. Artists Palette sits on the edge of the Black Mountains, one of the ranges that surround Death Valley and create its unique microclimate. It can be accessed easily from the main park roads.

Danxia Mountain Range -- Nature's rainbow rocks Even if you’ve never heard of the Danxia Mountain Range in China, you’ve probably seen pictures of it — the Danxia Range looks like a rainbow-colored layer cake stretched across a wide undulating landscape. Named after the Danxia Mountain, the tallest peak in the range, the formation’s corrugated and layered landscape is the result of a complex combination of tectonic upheaval and climatic weathering and erosion. The sheer cliff faces and rounded tops of the Danxia Mountain are distinctively characteristic of long-term weathering and erosion by wind and water. The Chinese characters in the name “Danxia” means “red”, named after the rusty crimson color that constitutes the majority of the sandstone beds in the formation. The mountain range is an extremely popular geopark, and is also a UNESCO heritage site that is home to various temples and statues, as well as a variety of rare orchids that thrives in the region’s lush subtropical climate.

The Golden Snail

In the depths of the Indian Ocean, at a place where scorching-hot toxic water erupts from tall, black chimneys on the ocean floor, you will find an animal straight out of the pages of science fiction: the 'Scaly Footed Gastropod' (Chrysomallon squamiferum). This large snail, 3-4 cm long, gets its name from the 'skirt' of shiny, golden scales that cover the soft parts of its body. These scales are made of the iron sulphide minerals greigite and pyrite, or 'fools gold'. This snail is the only animal we know of that makes shells out of these minerals, and the surprises don't stop there. This snail has developed some of the most advanced armour in the natural world.

Its shell is made up of three, unique layers. At the base is a normal aragonite (calcium carbonate) snail shell, the outside of which is covered by a protein-rich organic layer. The outer surface is coated in a fine layer of pyrite. As well as making the shell outrageously shiny, the combination of these layers makes some of the best armour scientists have ever encountered. It can resist piercing, crushing, fracturing, bending and heating, all traits that help it survive the harsh environment and fierce predators at the hydrothermal vents where it lives. The armour is so good that the US military are studying it to make new forms of body armour.

Just think - how long until you see soldiers with snails on their heads?

Image Credit: http://goo.gl/Hl4Awx (with permission)

Further Reading: - More about these amazing beasts:http://goo.gl/2ZqEtN - The alien world they live in (video):http://goo.gl/pAAbXh - Pyrite in its common form: http://goo.gl/AiqOEw - What is a hydrothermal vent?:http://goo.gl/SHHGmu - Military snails: http://goo.gl/YLKV9N

Blood Falls - Dry Valleys, Antarctica

The Blood Falls are named after the bright, crimson red briny liquid that flows from the tongue of the Taylor Glacier. The liquid is stained crimson from the oxidising iron in the water. The iron is sourced from the weathering of the bedrock and is enhanced by microbial action.

This water flows to the surface only a few times per decade, possibly due to to changes in the weight of the ice above it. The water is hypersaline and extremely cold, but still harbours life- in fact is may contain up to 17 different types of microbes! Samples collects show that the liquid has almost no dissolved oxygen either which suggests that the microbes have evolved to make use of sulphate and ferric ions to respire. As the Dry Valleys are the closest that we can get to Mars without actually going there, Blood Falls provides an excellent analogue for studying the potential for life on Mars.

-MJA

Image credit: Peter Rejcek

Further reading: http://bit.ly/1GFIZxf

Ludicrous hematite shape!

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