GeologyRocks Fieldtrip

Hi All,

Katie and I are off to the Pentland Hills this weekend (Saturday, the 11th of October). We're off fossil hunting for Silurian critters such as trilobites, bivalves, etc. See here for more details: http://www.pentlandhills.ukfossils.co.uk/

If anyone would like to come along, please do so! There's a pub on the right-hand side as you head south on the A702 from Edinburgh and a car park just after it on the left:

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Modern dissication cracks
  • Location: Cambourne, Cambridgeshire
  • Date Taken (dd-mm-yy): 25/07/2008

Modern dessication cracks on the bed of a dried up lake. The lens cap is 52mm in diameter. The cracks were a good few centimetres deep.

Glacial Valley
  • Location: Holyrood Park, Edinburgh, UK
  • Date Taken (dd-mm-yy): 05-10-2008

Classic U-shaped valley in Holyrood Park, Edinburg. The valley occurs between the hard sill of Salisbury Crags and the volcanic remnants of Arthur's Seat. The softer cementstone group were scoured out.

Amphibole

A common rock forming (igneous or metamorphic) group of minerals with complex chemical compositions, but mostly ferro-magnesian silicates. They are composed of double chain SiO4 tetrahedra. Amphiboles show two cleavage planes at around 120 degrees to each other.

Lustre

The way in which a mineral shines in light and described using terms such as vitreous, adamantine, etc. However, there are no rigid boundaries between the different terms.

Zeolite

A group of hydrous alumino silicates, which are characterized by their easy and reversible loss of water. There are 48 known naturally occurring zeolites. They are used in a variety of industries, including cat litter.

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Pseudomorph

A mineral with the outward form/shape of another species of mineral that it has replaced. There are three types of replacement: infiltration pseudomorph, paramorph, and encrustation pseudomorph.

See http://www.gc.maricopa.edu/earthsci/imagearchive/pseudomorphs.htm for examples and pictures.

Dinosaurs and the Cretaceous Terrestrial Revolution

The belief that dinosaurs underwent explosive species diversification just before they were wiped out is an illusion. A new study, published today, showed that the main evolutionary changes took place early in the dinosaur's history. The authors constructed a "supertree", which shows how species of dinosaurs evolved and carried out analysis on this to show when the major speciation events occurred.

The paper is published in Royal Proc. Soc. and the abstract and some more links are below:

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Goethite
  • Location: Cloghleagh mine, Kilbride, Co. Wicklow, Ireland
  • Date Taken (dd-mm-yy): 22 July 2008

Mammillated Goethite. Specimen is 6cm x 4.5cm.

Are you a member of the Geological Society and if so what level?

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