* Astronomy

A possible impact crater site is the feature known as St. Magnus Bay in the Shetland Islands.
A massive impact seems to be the cause for the peculiar shape of the bay.
The statistics of impact structures indicate that Britain should have still to be found impact structures up to tens of kilometres in diameter.
It has a diameter of eleven kilometres and is about 165m deep – , which is very deep for the coastal waters in the region. The crater is oval in shape because of the east-west geological compression that the area has suffered.


Position: 60.392920°N -1.609282°

It is suggested that the two craters were formed in late Tertiary times.
The Tertiary covers roughly the time span between the demise of the dinosaurs and beginning of the most recent ice age.
Ice age erosions have removing the rims and smoothed out the bottom of the crater.
In size the submarine St. Magnus Bay crater would rank among the dozen or so largest terrestrial impact features and is thus an important object for further study.

The volcanic rocks of the small island Papa Stour forms the southern rim of St, Magnus Bay...


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An ignimbrite from the Eshaness suite has yielded a Rb-Sr isochron age of 365 ±2 Ma. Geochemically, the lavas of the Melby Basin have been shown to be transitional between calc-alkaline and tholeiitic and have the characteristics of a suite formed by extensive fractional crystallisation.