Crustal accretion in and around Iceland

Abstract

Since the advent of the new global tectonics, geological problems and processes are being redefined in terms of plate tectonics. This is particularly so in Iceland, which is traversed by the divergent boundary between the Eurasian and North‐American plates and at the same time is a prominent hotspot. Many of the peculiarities of Icelandic geology and geochemistry appear now to be understandable only in these terms, and as a result, investigations in Iceland should shed light on various processes taking place under water along the more inaccessible oceanic ridges.Each period of human history has its own way of looking at the earth. In the Middle Ages, Mount Hekla, Iceland's most famous volcano, was reputed to be the gateway to Hell. Science oftentimes grows more by replacement than by addition, and the Medieval scheme was superseded by a new one which, surprisingly, at times even appeared to hold more questions than answers: Why is Iceland there at all, in the middle of the Atlantic? It looked like an accident of nature. Wegener [1915] interpreted Iceland to be a relic of continental scum left from the separation of Greenland from Europe, although earlier [Wegener, 1912] he had contemplated something similar to seafloor spreading [Jacoby et al., 198O]. H. Hess (personal communication, 1966), one of the pioneers of the new geology, also felt that Iceland did not fit into the idea of seafloor spreading and Belousov [1970] actually used Iceland as a strong argument against that hypothesis.