Geobulletin alpha

Map: Thickness Of The Crust 

A ten km contour interval? Well yes, if  you are mapping the thickness of the earth's crust! This map brings out beautifully the distribution of the two distinct types of crust on earth. Crust making up the continents is granitic to andesitic in composition, buoyant and is old. Crust making up the ocean basins is mafic in composition, gravitationally unstable (it is heavier and it subducts)

Journey to the centre of the Earth - on a toilet roll 

Today's new ELI is 'Journey to the centre of the Earth - on a toilet roll; just how thin is the crust we live on?' We seldom stop to consider the true scale of many features of the Earth. This activity aims to enable pupils to visualise the thickness of the crust in relation to the rest of the Earth. It also helps them to appreciate the difference in depth between the oceanic crust and

The Evolution of Living Dinosaurs 

Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage . 2014. Benson, et al. PLoS Biol 12(5): e1001853. An international team estimated the body mass of 426 dinosaur species based on the thickness of their leg bones. The team found that dinosaurs showed rapid rates of body size evolution shortly after their

Estimating sauropod intervertebral cartilage thickness from CT scans 

[This is part 4 in an ongoing series on our recent PLOS ONE paper on sauropod neck cartilage. See also part 1, part 2, and part 3.] Here’s a frequently-reproduced quote from Darwin: About thirty years ago there was much talk that geologists ought only to observe and not theorise; and I well remember some

How thick is the cartilage in necks of extant animals? 

Last time, we looked at how including intervertebral cartilage changes the neutral pose of a neck – or, more specifically, of the sequence of cervical vertebrae. The key finding (which is inexplicably missing from the actual paper, Taylor and Wedel 2013c) is that adding cartilage of thickness x between vertebrae whose zygapophyses are height y above

Evaporites 

If you evaporate a 1000m column of sea water only 1.5m of evaporites are produced. Given this, how would you account for the 2km thickness of Permian Zechstein deposits? In your answer make reference to the sequence of minerals you … Continue reading

Goniatites from the upper Devonian of New York 

On a recent trip up to the Buffalo area I chanced across a recent fall along the Lake Erie cliffs. It was rock from the upper Devonian layers that lie above the Moscow formation. The geology is well documented in this area but when you have a random jumble of rock at the base of a cliff it becomes a little more difficult to figure out. As I was exploring the rock fall I found a number of good examples of Goniatites.Specimen #1 Specimen #2Specimen #3Sadly they are not detailed enough to [...]