age of the
Middle Jurassic, showing the position of the Rockall Bank (RHB), and the Rockall Trough to the immediate southeast The nature of the crust beneath the Rockall Trough has long been a matter of debate. Originally thought to be
oceanic crust, it is now generally considered to be highly stretched
continental crust. However, some groups of researchers continue to favour either oceanic or transitional style crust, particularly at the southern end of the basin. The Rockall Basin forms part of a chain of highly extended
Mesozoic rift basins between the
Charlie–Gibbs and
Senja fracture zones. It includes: the
Faroe-Shetland Basin, the
Møre Basin, and the
Vøring Basin. There are indications that the Rockall Basin developed within an earlier rift system, which is likely to be of
Triassic to Middle
Jurassic in age, by analogy with the nearby
Slyne-Erris Basins. The age of the main rift phase in the Rockall Basin is strongly debated, with Late Jurassic, Early-, Mid- and Late
Cretaceous all being suggested. During the
Jurassic period, the Rockall Trough formed a
seaway between the emergent Rockall-Hatton landmass (equivalent to the modern submerged Rockall Bank) and the emergent Hebrides Platform (comprising the modern
Outer Hebrides). One of the features of the Rockall Trough is the
Anton Dohrn Seamount. It lies beneath the surface, rising from the surrounding
seabed. The plateau formed approximately 55 million years ago, a
continental fragment formed between Greenland and Europe when the ancient continent of
Laurasia was split apart by
plate tectonics. The
Rockall islet is the highest point of the plateau, rising above sea level. It is made of a type of
peralkaline granite.
Economic geology To date, there has been comparatively little drilling to explore for oil and gas within the Rockall Basin and only two discoveries have been made: Benbecula in the northern UK Rockall (
Shell originally
Enterprise Oil) and Dooish in the northern Irish Rockall (Shell originally
Enterprise Energy Ireland). The discoveries show that, at least locally, there is a working
petroleum system. Rights to exploit these resources are disputed between the United Kingdom, the
Republic of Ireland,
Iceland and the
Faroe Islands (a possession of
Denmark). This topic is addressed in
Rockall Bank dispute. ==Ecology==