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Showing posts from October, 2013

Insects that walked with dinosaurs: exceptional preservation in Cretaceous amber

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I've been looking again at some amazingly well-preserved insects trapped in Cretaceous amber.

Amber is in some ways the best preserving medium of fossil plants and animals known. The fossils are preserved in three dimensions, with great surface detail, and allow snapshots of interactions between animals or between animals and the flows of resin that engulfed them. No other style of exceptional fossil preservation can compare.

The oldest ambers with included animal fossils date back to the Triassic, but the best known early occurrences are Cretaceous in age, from Lebanon, France, Burma/Myanmar and New Jersey (USA). The New Jersey material comes from the Raritan Formation (Turonian, ca 90 Ma), excavated (from lignite occurring 6 to 10 feet below the surface) at a locality near Sayreville, New Jersey, USA. The amber is thought to have been produced by a forest of Cupressaceae in a warm temperate or sub-tropical environment (Grimaldi et al. 2000).

The amber represents aged, hardened r…

Jan and Cora Gordon: Behind the Film

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A large hard back book printed in 1935 just arrived. Its title is “The Big Book for Girls”, but what interested me was the seven-page article by Jan and Cora Gordon called “Behind the Film”



They start with a small story about how widely appreciated the cinema already was: “The film has even penetrated to the Arctic Circle, where on one occasion a righteous Eskimo dashed from the audience and stabbed the villain while the surrounding white men remained callously in their seats.”

They go on to describe the process of film-making and the “self-hypnotism” of the actors, informed by their visit to Hollywood seven or so years earlier. The full story of that journey was published in 1930 as “Star-Dust in Hollywood” and began with Jan Gordon recuperating in a Los Angeles house. When I visited Los Angeles in April 2012 I found that many of their observations still resonate today, eighty five years later.

In "Chaplin: The Mirror of Opinion", David Robinson writes that Jan and Cora Go…

Viking Art

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As it has turned out I have quite a strong association with Viking culture and Viking art.
I grew up in Yorkshire, surrounded by Norse place names (including the main streets of my home town) and it was fun to find familiar words during the years we later lived in Norway. There was also Jorvik at York (visited many times over the years, without and with kids); the battleground of Stamford Bridge (site of the last great Viking battle in 1066, following the burning of Scarborough in September of that year); and the Gauber High Pasture "Viking Site" at Ribblehead (excavated by Alan King). Numerous Viking artefacts have been discovered by detectorists in the Northern counties.
In subsequent years (1987, 1995) there were visits to Lindisfarne, site of the early Viking attack against England in 793 (I remember abandoned cars on the tidal causeway!) and beautiful peaceful Iona, which was raided by Vikings in 802. We saw a tower built to defend against such attacks in Ireland at Monis…

Calcite twinning: the four classes

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Calcite (Calcium carbonate) is a very common mineral, but fascinating in the vast variety of crystal forms it assumes, including some beautiful symmetries produced by the phenomenon of crystal twinning.

The crystals are trigonal, meaning that there is a single axis of three-fold rotational symmetry (the c-axis) as well as three equal axes perpendicular to the c-axis. They occur in a myriad of forms, from squat rhombohedra to flat-ended prisms to elongate pointy scalenohedra. Some crystals display very large numbers of faces.

Here is an example of an untwinned calcite crystal, 67 mm tall from the Rotherhope Fell Mine, Alston Moor, Cumbria, England (collected in 1922).



The complex shapes produced by twinning have long been admired and here is a page from a famous mineralogy textbook by Edward Dana (6th Edition of "The System of Mineralogy" 1904). The first edition of this work was produced by James Dwight Dana in 1837.


Then, as now, four distinct classes of calcite twin were …