Ore search heeds Atlantic lava

Press, Volume CXV, Issue 33804, 29 March 1975, Page 11

Ore search heeds Atlantic lava

Within the deep valley that bisects the Atlantic Ocean evidence has been found of lava eruptions of the type that is now widely believed have been responsible for many of the world’s ore deposits. writes Walter Sullivan in the “New York Times.’’ The finding lends added weight to this concept of

ore genesis. Geologists hope that such an understanding of the process will lead to a more educated and effective search for raw materials now in dwindling supply. The discovery was made during an intensive study of the Atlantic floor between Cape Hatteras in North America and Cap Blanc in north-west Africa. From the theory of sea-floor spreading that has gained wide acceptance in recent years it is believed that Cap

Blanc and Cape Hatteras once adjoined one another. The Trans-atlantic Geotraverse study is focusing on the ' path along which, according to that theory, those two regions pulled apart. The process responsible for these motions, it is believed, cracks open the mid-Atlantic forming a rift valley down its centreline where lava eruptions constantly produce new sea floor. From a variety of clues it is suspected that this pro-

cess is also responsible for many of the world’s ore deposits. Water circulating through the material that rises to fill the centra! rifts leaches out of it a variety of metallic, compounds that are carried into cracks of the rock and solidify into veins of ore. When such deposits are lifted from the sea, either as islands or where sea-floor spreading thrusts them up against a continent, they become accessible to exploitation.

The ore deposit that gave copper its name is thought to have been formed along a mid-ocean ridge, a remnant of which has been thrust up from the Mediterranean Sea as the island of Cyprus. At one time or another almost all the ancient civilisations of that region derived their copper from Cyprus. The Romans did so and named the metal “cuprium” from the name of that island — a word that in English has been corrupted to “copper."